2zz-ge technical article... learn something

[GTS LAID]

again in pursuit for info about our engines I came across this... the original tech. article when the 2zz engine designers presented at an SAE conference.

most likely it'll be over the heads of 95% of the people on this board... its for that 5%.

http://www.radphys.com/2zz_ge_article.pdf

enjoy ... it cost me $10...

[t2000gts]

this directly deals with all the issues in that aftermarket cam thread...and explains it brilliantly in an easy to understand format.

so far, i have only one question. will the amount of friction from the slipper follower on the 2ZZ over 6000rpm result in any long term wear effects compared to the roller followers on the K20A and other honda motors after their lift engage point? do the hondas even use rollers that high up?

EDIT: also explains maybe why everyone's 2ZZ's lift on the dynoes kicks in at 6200 and not 6000...there's indeed a 'kickback' effect with the lock pin.

[GTS LAID]

i dont know if they use rollers that high .. but lets assume they do...

for toyota engineers to go from the "new hip thing to do.." which was rollers at the time (and still is) they must've had a reason... now we need to find out what that reason is...

crane, crower, anyone out there care to tackle that challenge??

[2000GTSDRAGON]

Thanks man
2000GTSDRAGON

[t2000gts]

after further reading the part about the lock pin that engages lift...what was "acceptable" wear? what's that mean for real world use for us? does this mean after repeated 6000+ revving, after like 100k miles, the pin will just wear out and no more lift until it's replaced?

[autxr]

I don't care about the pin, that can be replaced (probably a very cheap part with high labor effort).

The sustained 1G cornering without sucing air from the oil sump is what concerns me. They basically tell you right there, over 1 G and you better make some provitoins for keeping oil pressure up. I *know* I can pull over 1 G sustained on autocross and road courses.

Scott

[gts24]

thanks laid for posting this information.

[GTS LAID]

scott is that b/c the oil is pretty much slumped on one side of the oil pan??

[GTS LAID]

Some questions / concerns / Problems:

1. the lift pin... this thing is really written proof that repeated cycling from low-high will eventually lead to disengagement of lift cause the pin will keep kicking back out... and replacing 4 pins in the middle of the engine aint cheap.

2. The oil problem that scott brought up... are they mentioning that the 2zz doesnt suck air till 1.0G of force b/c they want to impress us or warn us... what do other engines handle??

is this grounds for considering a dry sump system if the car is to be subjected to high G forces for long periods of time?

3. on page 5 they talk about manifold to exhaust pipe aperature value.. and say that an aperature of 0 will result in 0 power loss... what the hell are they talking about.. i'm pretty sure they're not talking about the diameter of the pipes... so what are they talking about.. and how can we make the thing 0 if we dont care about manufacturability or emissions.

[gts24]

Originally posted by GTS LAID
Some questions / concerns / Problems:

1. the lift pin... this thing is really written proof that repeated cycling from low-high will eventually lead to disengagement of lift cause the pin will keep kicking back out... and replacing 4 pins in the middle of the engine aint cheap.


This is definitely cause for concern..... I would like to know if this type of thing has had to be done for anyone yet. Cuz I hit lift ALOT during the day......

[GTS LAID]

well we've gotten threads in the past where people go "AHHH MY LIFT IS NOT WORKING"

thats the first concern...

also i'm reading another article that i got about the actual engine.. and i gotta tell you guys.. I'm very impressed... the 2zz motor is a VERY strong engine... I'll post the article tomm. morning...

damn all these articles are costing me an arm and a leg ($10 a piece.. and i've gotten 6 so far)

[gts24]

Originally posted by GTS LAID

damn all these articles are costing me an arm and a leg ($10 a piece.. and i've gotten 6 so far)

believe me your work is well appreciated and does NOT go unnoticed.

[SlowPoke]

Yes your work is definately noticed, we really appreciate you shellig out some bucks to educate us all, thank you!!

[GTS LAID]

thanks guys.. i appreciate the ... umm... appreciation.. lol...

[celicauk]

Nice one GTS, interesting reading for me :)

[Raymund]

How could have I missed this!! GTS laid, the link is not working anymore. Is there anyplace where I can read up on the article?

Originally posted by autxr
I don't care about the pin, that can be replaced (probably a very cheap part with high labor effort).

The sustained 1G cornering without sucing air from the oil sump is what concerns me. They basically tell you right there, over 1 G and you better make some provitoins for keeping oil pressure up. I *know* I can pull over 1 G sustained on autocross and road courses.

Scott

hmmm.. I dont know if I should be amazed or troubled!? In that case it would be a wise and cheap investment to buy a pressure gauge. Autometer sells their 2" electrical gauges for only $40

[GTS LAID]

i dont know what to tell you raymund.. it seems to work fine over here... try again.. if it still doesnt work then i can email it to you without a problem...

[Kit99bar]

Who Said that our header was so good that the aftermarket couldnt make better than them?

Just look at figure 15 and the discusion right before it

it clearly states "was set to the present level as a compromise between power....."

if someone made it with an aperture = 0 it would gain us power

can someone check and see if I read this right

[GTS LAID]

yes thats what i was asking about b4...

since we dont give a sh1t about emissions / manufacturability since we'd be paying for these...

maybe thats what TRD did... reduced the aperature to 0 and dealt with the manufacturing and emissions issues ... would justify the 800 dollar cost..

btw on a side note the tundra headers are 800 dollars.

[Kit99bar]

what is the aperature? a space betwen the exhaust manifold and pipe?

I dn't get it entirely

it looks if we make the aperature size = 0, it will double power in that area

[GTS LAID]

well normally aperature is the area of an opening... like the aperature of a camera... but it doesnt make sense in this case...

maybe one of the mech. guys can help us out with this tom. morning.

[Kit99bar]

someone explain figure 15!!!! :)

[gts_hypertek]

what program do u use to open the file?

[gts24]

Originally posted by gts_hypertek
what program do u use to open the file?

Adobe Acrobat reader ,,, here's a link to download the NEWEST version.

http://download.com.com/redir?pid=8338119&merid=50607&mfgid=50607&ltype=dl_dlnow&lop=link&edId=3&siteId=4&oId=3000-2378-8338119&ontId=2378&destUrl=%2F3001-2378-8338119.html

I took you through all the bs,, you should be able to click that link and be redirected to the download

[autxr]

My '73 Celica will register ZERO oil pressure in a sustaind right hand turn at about 0.8 G's.

Dry sumps are nice, but expensive, and hard to deal with. The solution is an Accusump (oil accumulator). It just pisses in the oil when your pressure drops.

Yes, the pressure drop would be from all the oil being pressed to one side of the oil pan.

Scott

[gts24]

Originally posted by autxr
My '73 Celica will register ZERO oil pressure in a sustaind right hand turn at about 0.8 G's.

Dry sumps are nice, but expensive, and hard to deal with. The solution is an Accusump (oil accumulator). It just pisses in the oil when your pressure drops.

Yes, the pressure drop would be from all the oil being pressed to one side of the oil pan.

Scott

It would definitely be interesting to have a decent oil guage to check things out when at a road course / autoX......

[icyjaws]

yea thats a realy intresting paper i know chui gave that paper a a bunch like it to me and a couple other poeple like a yr+ ago. He got them for free of ofcourse cause he works for ford or atleast did.

[Griffin]

Theres also a nice SAE paper on the block construction.

Yes its a stout motor - all Toyota high performance engines are generally rediculously overbuilt - you wann see stout? check out the bottom end on a 1UZ-FE 4.0 Lexus V8 - were talkin a friggin *6* Bolt main.... and the chevy guys cream their jeans over a 4 bolt...


To answer the oil questions here is some relevant information:

When TRD and Toyota Motorsports prepped the Long Beach Grand Prix Pro-Celebrity cars this year they all got Accu-sumps (basically a giant oil accumulator if you will) installed to correct the problems with burning the number 2 and number 3 main bearings they had last year. They worked flawlessly. They were actually T-ed in at the oil filter mounting adapter too. So yeah - oil pressure is an issue - but Dry sump isn't necessarily necessary, the extra quart of oil in teh accu-sump did the job perfectly. If your racing its a VERY good idea - I mean - its insurance anyways - this car lives an breathes oil - it runs the VVTi actuators and the variable lift system as well as performing all of its standard lubricational functions.

I'm gonna look into the exhauist aperture issue - I don't remember reading that bit - and I'll let y'all know what I figure out.

Griffin

[Griffin]

Ohh okies - the exhaust thing is easy.

The way the exhaust for the Celica is built you have the manidold pipe which extends past the flange. You then have the female portion on the downpipe that envelops this pipe BUT it seals against the FLANGE GASKET, not the pipe - this results in some amount of clearance between the atual pipes themselves. - If you've ever tuned exhaust before you know that anythign that disrupts the flow creates power loss - the reason for this is it breates backpressure that the engine has to expend horsepower to overcome (in other words it has to use piston force to push the exhaust out which equates to wasted energy). The gap between the 2 inside pipes themselves is the aperture they refer to and that is illustrated in figure 15. If you look at it you can see teh flangeswhere the reverse C shaped portion of the front pipe envelops the exhaust manifold outlet.

So anyways if you took a pipe of the EXACT same diameter and butted it up to the outlet pipe on teh exhaust manifold and created what would be for all intents and purposes one unbroken pipe you would consequently have zero or minimal power loss. This is not practical from a mass manufacturing standpoint because the cost of creating pipes to to that exact a spec and the care and effort needed to assemble them would hardly be worth the effort in terms of cost vs power gains.

Does that explain this adequately I hope?

[ace3]

Originally posted by Griffin
they all got Accu-sumps (basically a giant oil accumulator if you will) installed to correct the problems with burning the number 2 and number 3 main bearings they had last year. They worked flawlessly. They were actually T-ed in at the oil filter mounting adapter too.

Can you explain this any better? I've been road racing my GTS for a little while now, and have been worried about losing oil pickup. I hadn't heard that the Celebrity Celica's were using the Accusump system.

Any ideas how they mounted it? Can you explain at all on the "t-fitting at the oil filter mount"??

Thanks for your time...

[GTS LAID]

Originally posted by Griffin
Ohh okies - the exhaust thing is easy.

The way the exhaust for the Celica is built you have the manidold pipe which extends past the flange. You then have the female portion on the downpipe that envelops this pipe BUT it seals against the FLANGE GASKET, not the pipe - this results in some amount of clearance between the atual pipes themselves. - If you've ever tuned exhaust before you know that anythign that disrupts the flow creates power loss - the reason for this is it breates backpressure that the engine has to expend horsepower to overcome (in other words it has to use piston force to push the exhaust out which equates to wasted energy). The gap between the 2 inside pipes themselves is the aperture they refer to and that is illustrated in figure 15. If you look at it you can see teh flangeswhere the reverse C shaped portion of the front pipe envelops the exhaust manifold outlet.

So anyways if you took a pipe of the EXACT same diameter and butted it up to the outlet pipe on teh exhaust manifold and created what would be for all intents and purposes one unbroken pipe you would consequently have zero or minimal power loss. This is not practical from a mass manufacturing standpoint because the cost of creating pipes to to that exact a spec and the care and effort needed to assemble them would hardly be worth the effort in terms of cost vs power gains.

Does that explain this adequately I hope?

yes yes yes.. this all makes sense now... i follow...

so all we'd have to do if find an equal diameter piping and weld it shut... not really a major problem...

theres an article in SCC a couple of months back on back pressure and some myths about what people thought... I'm gonna scan it and put it up.

As for the engine block design article... its a great one and really goes in depth into the type of material they used for their MMC composite... its might be of special interest to cam and piston manufacturers...

heres that article:

http://www.radphys.com/MMC_engine_info.pdf

[t2000gts]

Originally posted by autxr
My '73 Celica will register ZERO oil pressure in a sustaind right hand turn at about 0.8 G's.

Dry sumps are nice, but expensive, and hard to deal with. The solution is an Accusump (oil accumulator). It just pisses in the oil when your pressure drops.

Yes, the pressure drop would be from all the oil being pressed to one side of the oil pan.

Scott

yep, TRD told me a while ago their guys use accusumps for the GTS.

they were experimenting also with putting a supra oil pump rotor in there, but it didn't work out.

i think 1.0g is impressive. how many cars are going to hit that? except the hotchkis guys better be careful.

so would this affect anybody other than hotchkis on a road course or autox? how do you hit 1.0g in anything if the car can't even hold over .90-.95g with the wheel locked to one side and accelerating.

[t2000gts]

Originally posted by GTS LAID


yes yes yes.. this all makes sense now... i follow...

so all we'd have to do if find an equal diameter piping and weld it shut... not really a major problem...

theres an article in SCC a couple of months back on back pressure and some myths about what people thought... I'm gonna scan it and put it up.

As for the engine block design article... its a great one and really goes in depth into the type of material they used for their MMC composite... its might be of special interest to cam and piston manufacturers...

heres that article:

http://www.radphys.com/MMC_engine_info.pdf

if i was gonna get new pistons, i would want forged titanium :)

[Griffin]

Originally posted by ace3


Can you explain this any better? I've been road racing my GTS for a little while now, and have been worried about losing oil pickup. I hadn't heard that the Celebrity Celica's were using the Accusump system.

Any ideas how they mounted it? Can you explain at all on the "t-fitting at the oil filter mount"??

Thanks for your time...

An Accusump is basically just a really big (over 1 quart capacity) accumulator - on one side of teh piston you have compressed air and on the other side you have oil. How it works is that under normal operation oil pressure keeps the accumulator full of oil. UNder extreme handling conditions if the pump sucks some air and cavitates, the system pressure drops and the air pressure on the back side of teh accusump accumulator's piston pushes this "reserve" oil into the system. This extra oil is generally enough to get you through the cavitation event in the oil pump and the extra quart of oil introduced into the system is also enough to get the pickup submerged again.

As for how its plumbed in I'm afraid I may have made it sound easy and its not - they had to machine and adapter plate for installation between the Oil Filter Bracket and the Block - basically it is simple a take-off that allows them to plumb the accusump into teh pressure line before the oil even enters the filter. I am not privy to teh exact details of the design but if you contact TRD they could probably get you some drawings or maybe even custom fab one for enough $$$ Hope this answers your question...

Griffin

[Griffin]

Originally posted by t2000gts


yep, TRD told me a while ago their guys use accusumps for the GTS.

they were experimenting also with putting a supra oil pump rotor in there, but it didn't work out.

i think 1.0g is impressive. how many cars are going to hit that? except the hotchkis guys better be careful.

so would this affect anybody other than hotchkis on a road course or autox? how do you hit 1.0g in anything if the car can't even hold over .90-.95g with the wheel locked to one side and accelerating.

I don't think it affects anyone except extreme duty drivers (IE auto cross or circuit racing)... probably not a bad idea if your seriously drag racing either though.

Griffin

[ace3]

Originally posted by Griffin
they had to machine and adapter plate for installation between the Oil Filter Bracket and the Block - basically it is simple a take-off that allows them to plumb the accusump into teh pressure line before the oil even enters the filter.

that's exactly what i figured they did.... well, i do have access to a CNC machine... ;)

what about an aftermarket oil pan (baffled/windage tray)? anyone know of anything?

[Kit99bar]

thansk for the info griffine

Glad to see you aboard newcelica.org

[GTS LAID]

ya dude you have a lot of good info... welcome aboard...

[autxr]

so would this affect anybody other than hotchkis on a road course or autox? how do you hit 1.0g in anything if the car can't even hold over .90-.95g with the wheel locked to one side and accelerating.

You must not get to the autocross section very often. ConeKiller was just posting his GEEZ info from the last big autocross. He peaked at 1.3 G's, and sustained over 1 G isn't that uncommon. There is a stretch in one sweeper where he hits that 1.3 G peak and averages right at 1G.

That is with STOCK springs, and some nice Koni shocks, and a stock sway bars.

I could pull the Hotchkis numbers with any of several suspension parts out there, the most important thing is a good set of tires and a good alignment.

Scott

[t2000gts]

Originally posted by autxr


You must not get to the autocross section very often. ConeKiller was just posting his GEEZ info from the last big autocross. He peaked at 1.3 G's, and sustained over 1 G isn't that uncommon. There is a stretch in one sweeper where he hits that 1.3 G peak and averages right at 1G.

That is with STOCK springs, and some nice Koni shocks, and a stock sway bars.

I could pull the Hotchkis numbers with any of several suspension parts out there, the most important thing is a good set of tires and a good alignment.

Scott

ah, is it because there's an entry and exit for a corner and you're already moving when you enter, and for a skidpad test, you start from a stop until the car just loses traction?

[autxr]

It is easier to pull high G's in a larger radius turn (all the skid pad numbers are on a 200 ft? circle), mostly, we can abuse the 1G mark by using better tires. If the coeeficient of friction is higher, then the lateral G's will be higher.

I could go to the dealership, get a brand new Celica with NO mods, put Hooiser autocross tires on it and easily pull over 1G on a skid pad.

Scott

[t2000gts]

is the 2ZZ only an all-aluminum block or the 1ZZ too?

[autxr]

The 1ZZ is aluminum, but uses steel cylinder sleeves.

Scott

[Raymund]

okay, I was able to down load the article. Very intresting stuff, if only this type of info was available in the cars brochure.

I'm VERY worried now. I have most certainly driven the car past 1G specially on long sweepers with sustained 4 wheel drifts. I'm sure my 2 and 3 mains bearings are severly worn if thats the case with last years Celebrity cars. How about the valve train, Griffin? Were their any issues with cam& rocker wear also due to oil scavenging?

My bud with a SOHC vtec motor encountered severly worn rockers on piston1 due to high G loads on right turns on the track.

http://www.imagestation.com/picture/sraid10/pee6c57b2e0c54771ba870fa793b9ebab/fe05cc77.jpg
note* the right rocker is sourced from a used engine in replacement and that rocker had on more miles.

My advice if your going to autox or track lap, to fill up on engine oil all the way up to the full mark on the dipstick.

[ap1f20c]

Both the K-series (RSX) and the F-series (S2000) use roller followers exclusively (to 9200 rpm in the case of the F20C). The lift/degree measurement the authors provide is useful, but you can compensate for that with cam lobe design. A slipper offers more lift for a given design because the actual contact point between cam and follower moves along the follower axis perpendicular to the axis of rotation. Combined with the proper curvature on the slipper pad, you can actually create some interesting lift profiles through the interaction. I think it also simplifies the cam profile design a bit vs. a roller setup.

In terms of wear, I've seen 100k mile VTEC motors with no problems on the slipper followers. Get the wrong cam design, or improper adjustment (or one of the biggies is a lost motion assembly, or LMA, that can't handle your cam lift) and you will wipe out the pads and probably the cam. But OEM, or with proper aftermarket parts, the slippers should last the life of the engine. Thus, I can't see Toyota not ensuring they'd have good reliability there either.

However, friction is a concern with slippers. Toyota's graph showed that the friction difference is less at high rpm, but since they didn't actually define the axes on the graph, its hard to say what that really means. Friction does not decrease with rpm, so I'm guessing the "friction" axis was friction losses as a percentage of hp (or friction as a percentage of total friction). Thus, the slipper approach still has a significant friction penalty, even at high rpms. Honda went to rollers because the rpms are getting higher and higher and in order to maintain durability and emissions with good power, you really need them. I do believe F1 guys are still using a follower design (as opposed to direct acting cams like motorcycles use), but I don't know if they use rollers or slippers. They're limited on their cam timing by piston location, so slippers might not be necessary (but they could be lighter - enough speculation :-).

From the cam design perspective though, the one thing that jumped out at me was that the authors seemed to imply that the cam lobes were heat treated/surface prepped after being placed on the camshaft proper. This would imply then that both sets of lobes are given the same surface hardness. Thus, the supposed plight of aftermarket manufacturers shouldn't be such a big issue. Keep pushing them guys, someone will make you cams. :-)

AP1F20C

Originally posted by t2000gts
this directly deals with all the issues in that aftermarket cam thread...and explains it brilliantly in an easy to understand format.

so far, i have only one question. will the amount of friction from the slipper follower on the 2ZZ over 6000rpm result in any long term wear effects compared to the roller followers on the K20A and other honda motors after their lift engage point? do the hondas even use rollers that high up?

[Griffin]

No - they didn't MENTION any wear issues on the valvetrain, but then again most of those cars done have more than 100 or 200 miles at the absolute max, and when they crater the engines they tend to just toss em and get a new one. But with the design of the rockers I doubt you have much to worry about - the roller for the low lift isn't likely to wear and the slipper for the high lift cam is made from basically the same alloy that Toyota has been using on their valve adjustment shims for a LONG time now. Also - since they have an oil bathing system on the 2ZZ valve cover the valvetrain tends to stay very well lubricated compared to most motors.

If your worried about your bearings there are 2 pretty simple things you can do -

1 - Drain your oil through a clean white paper towel - after look in the towel and see if you see and flakes of bronze or grey metal.

If you see metal that looks like bearing material then

2 - drop your oil pan and plastigauge your rods - easy enough to do and if you catch them before things get too bad the chances of scoring the crank journals is fairly slim. - The bearings are designed to sacrifice themselves for the sake of the engine if necessary and they are relatively easy to check. Biggest pain is getting the pan down since they are held on with FIPG (Toyotas Fix In Place Gasket - basically a type of silicone RTV thats a PAIN in the butt to get off. Its also very good stuff though - better than anything I've seen from the aftermarket. If the rods look worn the mains probably will be too.

all that having been said - if your engine isn't making any knocking noises then your probably OK... One problem with those TRD cars is they take a fresh motor with very little break in and give it to someone who has no earthly idea how to drive.... thats big time hard on a car. A little slop & polish in your engine from a more normalized break in can do wonders for durability.

Griffin

[Griffin]

Originally posted by ap1f20c


From the cam design perspective though, the one thing that jumped out at me was that the authors seemed to imply that the cam lobes were heat treated/surface prepped after being placed on the camshaft proper. This would imply then that both sets of lobes are given the same surface hardness. Thus, the supposed plight of aftermarket manufacturers shouldn't be such a big issue. Keep pushing them guys, someone will make you cams. :-)

AP1F20C



Nods - I kind of thought this was a weird thing for them to say because if you check out the high and low lift lobes the surface finishing between the 2 is in reality VERY different. The low lift has a much more highly polished surface than the high lift cam, even when new. I had always assumed that this was simply because you desire different characteristics in a cam that runs on a roller and one that runs a slipper. But this doesn't seem totally consistent with what the SAE paper says.

Out of curiosity has anyone ever tried disabling the OCV for the VVTi and then jumping 12 volts to the VVTLi OCV to see what happens? I bet you could make monster power if you could manage to keep it running...

Griffin

[t2000gts]

Out of curiosity has anyone ever tried disabling the OCV for the VVTi and then jumping 12 volts to the VVTLi OCV to see what happens? I bet you could make monster power if you could manage to keep it running...

really...why?

i thought the paper had a graph of the 2ZZ with VVT-i and lift, and without VVT-i, but still with lift. the VVT-i only helped torque gains (not as much over 6000, but very noticeable under).

[Raymund]

Welp.. I think its too late. Whenever a change oil I always use a black clean pan. afterwards, I drain the pan onto a larger container. I always check the pan for debris and theres always a fair amount of bronze and grey metal particles left on the pan. I always thought this was a normal part of wear and tear. How much metal shaving would require a concern for further inspection?

btw. I took extra precaution in braking in the motor and I change oil in a religious basis- every 2K miles sometimes right after a track event

I have 28k on the odometer and the last 4 oil change I can recall seeing the same amount of metal shavings. Are the metal deposits suppose to increase if the bearings are worn?

[GTS LAID]

i'm wondering since these engineers wrote the paper then they must be quite proficient in english... I'm gonna try to get in touch with them.

[GTS LAID]

Raymund can you take pics next time you do an oil change... I'd like to email them to the designer guys and ask them about the bearing wear and the shavings in the engine...

[DaksGT]

Should the 1zz guys be worried about this as well?

[t2000gts]

i see a ton of crap when i change my oil.

i thought the engine was still dirty from the water ingestion deal. but who knows. i don't pull 1 G in any direction often (maybe hard braking? i almost never do that, i never need to, even at high speeds).

runs fine.

if your car runs fine, i guess you're ok. just make sure it doesn't happen again (can a bigger sump work as well or no?)

[Raymund]

Raymund can you take pics next time you do an oil change... I'd like to email them to the designer guys and ask them about the bearing wear and the shavings in the engine...

will do

[ap1f20c]

o.k., I was wrong in this assumption. The document clearly says that they were treated to different finishes - after the lobes were put on the shaft. Thus, it is possible to heat treat/finish the lobes separately. This is still good news, although its not quite as simple as finishing all the lobes the same way.

AP1F20C

Originally posted by ap1f20c


From the cam design perspective though, the one thing that jumped out at me was that the authors seemed to imply that the cam lobes were heat treated/surface prepped after being placed on the camshaft proper. This would imply then that both sets of lobes are given the same surface hardness. Thus, the supposed plight of aftermarket manufacturers shouldn't be such a big issue. Keep pushing them guys, someone will make you cams. :-)

[Griffin]

Originally posted by t2000gts


really...why?

i thought the paper had a graph of the 2ZZ with VVT-i and lift, and without VVT-i, but still with lift. the VVT-i only helped torque gains (not as much over 6000, but very noticeable under).

Because if you disable the VVTi (intake cam timing) actuator it defaults to a fully retarded position. I dont know exactly how tight the clearances are, but the top of the piston IS dished where the valves are and if you left it enabled and tried to jump on the VVTLi (variable lift) when the intake cam was sufficiently advanced (seeing as how it CAN advance to BTDC) you might manage to put a valve into a piston. Remember variable LIFT means the valve actually opens significantly further into the cylinder... I know I would feel like a moron if I chucked a valve through a piston just screwing around with my engine, thats why I havent ever tried it.... but man that cam is just so huge, it would be cool to see what if any power it makes at low/mid RPMs.

But Hey - Im not suggesting anyone try it - I'm just curious if anyone actually has.

Griffin

[Griffin]

Originally posted by Raymund
Welp.. I think its too late. Whenever a change oil I always use a black clean pan. afterwards, I drain the pan onto a larger container. I always check the pan for debris and theres always a fair amount of bronze and grey metal particles left on the pan. I always thought this was a normal part of wear and tear. How much metal shaving would require a concern for further inspection?

btw. I took extra precaution in braking in the motor and I change oil in a religious basis- every 2K miles sometimes right after a track event

I have 28k on the odometer and the last 4 oil change I can recall seeing the same amount of metal shavings. Are the metal deposits suppose to increase if the bearings are worn?

The bronze shavings are probably a not the greatest sign. Everything in this engine is aluminum or iron except the babbit in the bearings. The bronze is an underlayer - the top layer is grey. If you wanna see what I mean head down to your local Toyota dealer buy any engine bearing and slowly file layers off the inside radius. It's pretty cool really :) But even so - if you arent knocking theres no reason to go grey with worry yet. Do as suggested and take a picture of what you get in your next oil change an dlet us take a look at it. SOME wear is normal, especially under hard use, but if your bearing are on teh way out its best to catch it before you get any scoring on the crank.

Griffin

[t2000gts]

Originally posted by Griffin


Because if you disable the VVTi (intake cam timing) actuator it defaults to a fully retarded position. I dont know exactly how tight the clearances are, but the top of the piston IS dished where the valves are and if you left it enabled and tried to jump on the VVTLi (variable lift) when the intake cam was sufficiently advanced (seeing as how it CAN advance to BTDC) you might manage to put a valve into a piston. Remember variable LIFT means the valve actually opens significantly further into the cylinder... I know I would feel like a moron if I chucked a valve through a piston just screwing around with my engine, thats why I havent ever tried it.... but man that cam is just so huge, it would be cool to see what if any power it makes at low/mid RPMs.

But Hey - Im not suggesting anyone try it - I'm just curious if anyone actually has.

Griffin

how would you advance the intake cam timing after disabling VVT-i?

or do you mean with the intake cam timing on retarded position, you'd make more power?

[DaksGT]

Originally posted by Griffin


The bronze shavings are probably a not the greatest sign. Everything in this engine is aluminum or iron except the babbit in the bearings. The bronze is an underlayer - the top layer is grey. If you wanna see what I mean head down to your local Toyota dealer buy any engine bearing and slowly file layers off the inside radius. It's pretty cool really :) But even so - if you arent knocking theres no reason to go grey with worry yet. Do as suggested and take a picture of what you get in your next oil change an dlet us take a look at it. SOME wear is normal, especially under hard use, but if your bearing are on teh way out its best to catch it before you get any scoring on the crank.

Griffin
Jesus now I am all worried.


I never took my car to autox or anything like that, I drive normal (shift at 4k), should I be worried?

[Raymund]

But Hey - Im not suggesting anyone try it - I'm just curious if anyone actually has.

I'm sure it wouldn't hurt to try it during idle. I dont think there will be any substancial amount of power gains below lift but I can only imagine the gains above 6k.

Out of boredom, I swapped out my buddies ecu on his GT with my GTS. As soon as we fired her up, the CEL lit up without even warming up. We knew the ignition/mapping as well as cam phasing settings are different but it still ran. However, the revs were limited to 7200rpms which baffled us!

[Griffin]

Originally posted by t2000gts


how would you advance the intake cam timing after disabling VVT-i?

or do you mean with the intake cam timing on retarded position, you'd make more power?




how would you advance the intake cam timing after disabling VVT-i?

Don't confuse VVTi with VVTLi - the cam advance and lift are controlled independently by 2 differenct OCVs (Oil Control Valves)

What I was saying was I wonder what would happen if the VVTLi high lift cam was enabled at lower RPM.

The reason I said to disable the VVTi actuator (which is what controls the position of the intake cam with regards to crankshaft position) was that if disabled the system is suppsed to default to a basically fully retarded position which should protect the piston from any possible contact with the valves. The system normally retards teh intake cam timing pretty far when it turns the high lift on anyways.

Like I said though - I havent had the balls to do it because I can't see living with the humiliation of puttin a piston through a valve just screwing around....

Griffin

[Griffin]

Originally posted by Raymund


I'm sure it wouldn't hurt to try it during idle. I dont think there will be any substancial amount of power gains below lift but I can only imagine the gains above 6k.



Applying the High lift cam below 6200 is eactly what I'm talking about... the little pins that shoot under the cam followers for the high lift can are applied by hydraulic (oil) pressure from an oil control valve in the head. What I was wondering is what kind of power could be make if you hotwired the OCV to a switch and could manually apply it at like 3K or 4K rpms... Or even right from the get go... - that cam is huge - with a high flow intake and exhaust I betcha it has the potential to build power MUCH faster than the low lift cam. The idle quality would suck though.

Griffin

[GTS LAID]

well for idle quality you can keep it on chill until 3k PRM... any conservative shift will land you there anyway in normal driving and shifting...

by asking this you're suggesting that the only reason toyota even has the switchover points high is b/c of fuel effiency (since it would go out of the window)

[Griffin]

Originally posted by DaksGT

Jesus now I am all worried.


I never took my car to autox or anything like that, I drive normal (shift at 4k), should I be worried?

Nah you have nothing to worry about

This is a condition exclusive to cars being used under extremely high load and high G applications - even driving the piss out of your car on the street will not expose it to these conditions. The issue at hand is the oil slinging off to one side of the pan under a VERY high G turn and allowing the oil pump to suck air - hence starving certain points of the drivetrain. This is almost impossible to do on city streets without getting yourself killed or the roads being totally empty so dont sweat it.

Grififn

[Griffin]

Originally posted by GTS LAID
well for idle quality you can keep it on chill until 3k PRM... any conservative shift will land you there anyway in normal driving and shifting...

by asking this you're suggesting that the only reason toyota even has the switchover points high is b/c of fuel effiency (since it would go out of the window)

Well yeah... I mean they pretty much said as much in that SAE paper... I forget the exact quote but the engineer said the low speed cam gave "flexibility at low speeds" - IE lesser performance, smooth idle, and better gas mileage.

I mean - if you put a hot cam in any car the idle and gas mileage get worse and the performance gets better.... But why re-cam when theres a massive cam already there. I just think it would probably give a way better 0-60 and 1/4 mile time assuming I'm not totally off base. This would also solve the problem in the 2002 cars where they they drop out of high lift between shifts because of the lower fuel cut if it worked. Then again maybe the car would just run like crap.

Griffin

[DaksGT]

Originally posted by Griffin


Nah you have nothing to worry about

This is a condition exclusive to cars being used under extremely high load and high G applications - even driving the piss out of your car on the street will not expose it to these conditions. The issue at hand is the oil slinging off to one side of the pan under a VERY high G turn and allowing the oil pump to suck air - hence starving certain points of the drivetrain. This is almost impossible to do on city streets without getting yourself killed or the roads being totally empty so dont sweat it.

Grififn

Thanx

[t2000gts]

Originally posted by Griffin


Well yeah... I mean they pretty much said as much in that SAE paper... I forget the exact quote but the engineer said the low speed cam gave "flexibility at low speeds" - IE lesser performance, smooth idle, and better gas mileage.

I mean - if you put a hot cam in any car the idle and gas mileage get worse and the performance gets better.... But why re-cam when theres a massive cam already there. I just think it would probably give a way better 0-60 and 1/4 mile time assuming I'm not totally off base. This would also solve the problem in the 2002 cars where they they drop out of high lift between shifts because of the lower fuel cut if it worked. Then again maybe the car would just run like crap.

Griffin

ah i get what you're saying now. i'm a newbie to this so don't mind me :)

is it just natural to retard the intake cam timing when you have a more aggressive cam?

it's sort of like just fooling around with the engine to get the lift lower and also tune it using other engine functions (or not using in this case). pretty ghetto :D

however, some people have lowered the lift engagement point with an Apex'i Power FC, and have noticed no power increases under 6000rpm. i think M SPEC was one of them, maybe you should ask him. i think that might be because VVT-i was still on and the ECU had no idea what to do....maybe disabling VVT-i, and getting the retarded cam timing would let it make power...if you could just rig it to turn VVT-i off at 5500rpm and back on at 6200 and have lift come on at 5500...that'd be cool.

i doubt you'd make power on that profile at 3k-4k though...maybe over 4k...well, more power than the normal 'under 6000' cam lobes...if you had more air and fuel in there. maybe a nitrous wet kit which gives a ****load more oxygen and fuel at the same time without too much headache. have an insane powerband.

[Griffin]

Originally posted by t2000gts


ah i get what you're saying now. i'm a newbie to this so don't mind me :)

is it just natural to retard the intake cam timing when you have a more aggressive cam?

it's sort of like just fooling around with the engine to get the lift lower and also tune it using other engine functions (or not using in this case). pretty ghetto :D

however, some people have lowered the lift engagement point with an Apex'i Power FC, and have noticed no power increases under 6000rpm. i think M SPEC was one of them, maybe you should ask him. i think that might be because VVT-i was still on and the ECU had no idea what to do....maybe disabling VVT-i, and getting the retarded cam timing would let it make power...if you could just rig it to turn VVT-i off at 5500rpm and back on at 6200 and have lift come on at 5500...that'd be cool.

i doubt you'd make power on that profile at 3k-4k though...maybe over 4k...well, more power than the normal 'under 6000' cam lobes...if you had more air and fuel in there. maybe a nitrous wet kit which gives a ****load more oxygen and fuel at the same time without too much headache. have an insane powerband.


is it just natural to retard the intake cam timing when you have a more aggressive cam?

Not necessarily - depaends on the cam itself - Cam tuning is kind of a black art... theres a lot of tweaking involved. The more you advance the timing the more valve overlap you create which is good - it allows the incoming air charge to actually force teh exhaust out of the cylinder - kind of like what hapens with equal length headers when the negative pressure pulse actually scavenges exhaust out of a cylinder to some degree. The idea is basically that the more Exhaust you get out the more usable air you can suck in.

But anyways depending on lift and duration you will make different amounts of power at different RPMs, but you also have to take into account the piston position if you have a lot of lift and an intake cam thats opening significantly before top dead center. Given that toyota is retarding the VVTi pretty far when they apply the high lift it PROBABLY means that the cam performs better with less overlap... but it could also be that they did it for the same reason I'm saying to disable it - to prevent piston contact.

i doubt you'd make power on that profile at 3k-4k though...maybe over 4k...

Nods - if you had it on a switch you could just play with it and see what worked best. You can actully turn it on using the active test section on the Toyota scann tool... hmm... maybe that would be the best way to try this - I'm gonna have to see if I can get y hands on one for a night.

Anyways it might not work out... just seems to me that theres some untapped potential there. Like I said - I may be wrong - but ever since the last time I had the valve cover off and was lookin at how huge the lobes are I can't stop thinkign about messing with it.

Griffin