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Forged Pistons for the 2ZZ-GE

14K views 31 replies 11 participants last post by  Celicasaur 
#1 ·
Without going into details that may be found in another tearful thread of mine, I might need new pistons... a leakdown test is forthcoming, but for now, I just want to get my facts straight.

Surprisingly, I found few threads with good detailed information on forged pistons, but here is what I've gathered thus far -- please confirm or correct as needed:

1. My options are either (a) Wiseco or (b) Mahle -- any others out there?

2. If I go with Mahle, I can have them dropped right in, no sleeves needed.

3. With Wiseco, I need sleeves.

4. Compression ratios -- Mahle is at 9.0, wiseco can be set custom? Recommended compression for my 12+ psi boost application?

5. Issues -- some Mahle pistons were mismatched causing problems? Anyone know more details? Wiseco pistons will cause piston slap and damage the cyl walls if not sleeved -- correct?

6. No other special parts needed.

Any other important details I've missed, things to consider? Important threads I've stupidly failed to find? Anything?

Thanks!

Jordan
 
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#2 · (Edited)
2. yes Mahel pistons are direct drop, and have special coating for stock sleeves.
3. yes you will need darton sleeve kit to go with the Wiseco.
4. i dont know much bout turbo i am all N/A. but 9.0 sounds good with 12+ psi. specially if the pistons are forged.
5. yes the intake side was hitting the intake valves, so they came out with a new version of the piston.
6. with mahel no, they supply everything. dont know about wesico i dont have those pistons
 
#5 ·
but jlitman i think 10 compression would be best for an sc tho or higher then 9 at least.

jlitman said:
Without going into details that may be found in another tearful thread of mine, I might need new pistons... a leakdown test is forthcoming, but for now, I just want to get my facts straight.

Surprisingly, I found few threads with good detailed information on forged pistons, but here is what I've gathered thus far -- please confirm or correct as needed:

1. My options are either (a) Wiseco or (b) Mahle -- any others out there?

2. If I go with Mahle, I can have them dropped right in, no sleeves needed.

3. With Wiseco, I need sleeves.

4. Compression ratios -- Mahle is at 9.0, wiseco can be set custom? Recommended compression for my 12+ psi boost application?

5. Issues -- some Mahle pistons were mismatched causing problems? Anyone know more details? Wiseco pistons will cause piston slap and damage the cyl walls if not sleeved -- correct?

6. No other special parts needed.

Any other important details I've missed, things to consider? Important threads I've stupidly failed to find? Anything?

Thanks!

Jordan
 
#9 ·
Celicahzn said:
but jlitman i think 10 compression would be best for an sc tho or higher then 9 at least.
I'd prefer something like 10:1 too; 9 just seems pretty low for my application.

With the above in mind, I plugged in the changes using some seemingly reliable online calculators and the end result is a loss of 4-6% of my power if I need to replace the pistons. That's fine if I can now ramp up the boost safely to 14+... but can I?


Smaay said:
im looking at a set of Mahle pistons right now that i just got from MWR. they are the new ones with the right dish sizes
Good to know! Was a bit worried about all that.

Just wondering, but is there some special thing MWR does to justify their price hike over buying directly from Mahle? Any idea as to whether it's possible to get pistons from Mahle with a custom set CR?
 
#10 ·
jlitman said:
Celicahzn said:
but jlitman i think 10 compression would be best for an sc tho or higher then 9 at least.
I'd prefer something like 10:1 too; 9 just seems pretty low for my application.

With the above in mind, I plugged in the changes using some seemingly reliable online calculators and the end result is a loss of 4-6% of my power if I need to replace the pistons. That's fine if I can now ramp up the boost safely to 14+... but can I?
yes you could do over 14psi, but i would still recommend getting darton sleeve kit, the sleeves can handle even more boost, and you will have peace of mind knowing nothing will probably go wrong at 14+ psi.

jlitman said:
Good to know! Was a bit worried about all that.

Just wondering, but is there some special thing MWR does to justify their price hike over buying directly from Mahle? Any idea as to whether it's possible to get pistons from Mahle with a custom set CR?
you will probably have to contact mahel and see if they can make you a custom set. but ones again since the pistons will be custom your probably going to end up spending the same amount of money, MWR has to make money of there products.
 
#12 · (Edited)
Is the Greddy SC even efficient at 14+ psi? In theory you should be able to run more boost and probably a little more ignition timing with the lower compression. I would say with a set of Mahale pistons and stock sleeves the motor should be safe to about 500 hp (an estimate judging by what MWR's turbo GT-S does), which leaves Greddy owners quite a bit of headroom. Just replacing the pistons should gain you a lot of security because the stock piston ring lands are WEAK. I see that as the main reason for upgrading the Mahale pistons. The ONLY 2 reasons I would Darton sleeve a block is if the block has OEM sleeve damage, or if you are going for BIG power. Save some money and stick with stock rods as they are very stout units, and stock sleevesif you dont have any OEM sleeve damage.
 
#13 · (Edited)
youngxlos said:
oh and by the way MWR doesn't really hike the price, i remember trying to check to see if i could find the mahel pistons for cheaper, but everywhere i found some they where just about the same price.
Yes they do. Check out these prices from Mahle http://www.importperformanceparts.net/imports/mahlepowpak-toyota.html

According to this thread they also significantly mark up the valves and springs... http://www.newcelica.org/forums/showthread.php?t=188039

Don't get me wrong, I'm not a cheapskate -- I certainly don't mind paying extra if it is because of some special treatment/coating they do to the parts, but just paying extra to help their profits is a little more charitable than I feel I need to be, especially for something generally costly like an engine build...

DYI01 said:
Is the Greddy SC even efficient at 14+ psi? In theory you should be able to run more boost and probably a little more ignition timing with the lower compression. I would say with a set of Mahale pistons and stock sleeves the motor should be safe to about 500 hp (an estimate judging by what MWR's turbo GT-S does), which leaves Greddy owners quite a bit of headroom. Just replacing the pistons should gain you a lot of security because the stock piston ring lands are WEAK. I see that as the main reason for upgrading the Mahale pistons. The ONLY 2 reasons I would Darton sleeve a block is if the block has OEM sleeve damage, or if you are going for BIG power. Save some money and stick with stock rods as they are very stout units, and stock sleevesif you dont have any OEM sleeve damage.
Cool -- good to hear this! Yep, based on Ronin over at Moremonkey who is running a 2.85" pulley, spinning the blower dangerously close to 16K at high engine revs, he is making almost 14 psi after the psi drop from his intercooler.

Miles Terry (milesplume) had (and soon I will have) a 2.9" pulley that he claims made over 16 psi, and takes the blower to over 15K revs at 8.5K engine RPM. According to my pulley calculator for the MP62, both are getting close to maxing out the blower, but they will work. I can't imagine going any smaller than 2.85", tho'.
 
#14 ·
MWR generally has 2ZZ stuff in stock - that, to me, is worth it. I don't like dealing with "companies" that carry no inventory and simply order what you order from them once you order it.
 
#15 ·
well i brought this up in a thread and boosted just said that i would need better pistons becuase of the rings and he said that i shouldn't change the compression its just the weak stock pistons that's all. I am proably gonna go 10.5 or 11 compresion on the blitz sc at 12 psi with N20 see how that does.

jlitman said:
I'd prefer something like 10:1 too; 9 just seems pretty low for my application.

With the above in mind, I plugged in the changes using some seemingly reliable online calculators and the end result is a loss of 4-6% of my power if I need to replace the pistons. That's fine if I can now ramp up the boost safely to 14+... but can I?



Good to know! Was a bit worried about all that.

Just wondering, but is there some special thing MWR does to justify their price hike over buying directly from Mahle? Any idea as to whether it's possible to get pistons from Mahle with a custom set CR?
 
#16 ·
I've been trying to dig up info from people w/ real world experience w/ the mahle pistons in the stock bores and from what i've gathered, MWR has the only car currently running them in stock bores. I really want to put these in and throw 18-20psi at the motor, but i want to make sure they are going to fit my bores before i tare the motor down to put them in. Are they gaurenteed to fit properly yet?
 
#18 ·
How about getting a cheap set of stock pistons in good condition and getting them treated with all sorts of magical powers like teflon coating on the skirts and maybe cryo'ing them (if that can even be done-I don't know, just tossing an idea in the mix)

I remember some guy on the F/I forum saying that he has an arrangement like that on his gt-s and running like 75 or 100 of nitrous...
 
#19 ·
Celicasaur said:
How about getting a cheap set of stock pistons in good condition and getting them treated with all sorts of magical powers like teflon coating on the skirts and maybe cryo'ing them (if that can even be done-I don't know, just tossing an idea in the mix)

I remember some guy on the F/I forum saying that he has an arrangement like that on his gt-s and running like 75 or 100 of nitrous...
Hmmm. I dunno if that would be less expensive / as reliable as getting the aftermarket ones. Also, the design of the ringlands themselves is different (beefier) on the Mahle and Wiseco pistons.
 
#21 ·
jlitman said:
Hmmm. I dunno if that would be less expensive / as reliable as getting the aftermarket ones. Also, the design of the ringlands themselves is different (beefier) on the Mahle and Wiseco pistons.
true that, jiltman. just a shame that the damn compression choices are either one extreme or the other. why oh why would they not make a stock c/r foged piston set for those who just want a stronger engine, but without having to sacrifice potential either way :(

mind you, would you say that stock pistons would be fine on a 75 shot on top of around 200-ish whp? (presuming i hit that figure)
 
#22 · (Edited)
Celicasaur said:
jlitman said:
Hmmm. I dunno if that would be less expensive / as reliable as getting the aftermarket ones. Also, the design of the ringlands themselves is different (beefier) on the Mahle and Wiseco pistons.
true that, jiltman. just a shame that the damn compression choices are either one extreme or the other. why oh why would they not make a stock c/r foged piston set for those who just want a stronger engine, but without having to sacrifice potential either way :(

mind you, would you say that stock pistons would be fine on a 75 shot on top of around 200-ish whp? (presuming i hit that figure)
Ehhh... I'm not the best person to ask. I've always been leery of N2O...

What size injectors and any engine management? I'm guesing you'll need to run much richer to cool things off with a 75 shot on top. You'd need to have a tuned map ready to load up that will pull timing and enrichen the fuel when you plan on spraying (greddy has a remote switch for that, I think). Also, what plugs are you using?
 
#23 ·
i may upgrade injectors if the n/a set up goes way better than expected with the power hike, but i might just manage on stock tbh (unless the duty cycle tells me otherwise)

i'd first get the car tuned n/a on pfc and then have timing slightly pulled for gas use...maybe even just use a seperate mini fuel cell with some insane 105 octane gas just for nitrous abuse. hopefully though, our 98 octane gas at the pumps may well suffice.

I keep hearing that 75shot is an acceptable 'limit' for nitrous on 2zz's, but this 75 on top of a lot of other n/a mods makes me a teeny bit queazy. maybe i should just stick with 50 if i stay stock, or go up to mahle's....
 
#24 ·
I would say a 75 shot is the safe limit on a stock bottom end with pump gas. You could probably bump it up to a 100 shot with 100+ octane, and a retarded timing map. Always monitor your knock index. You would be running a wet kit so upgrading injectors isn't necessary. Although I would reccomend upgrading to a 255lph fuel pump so your fuel pressures dont drop too much.
 
#26 ·
Celicasaur said:
Sound advice DYI' ;)

I think I finally know what set up I'm going to stick with. (after many months of thinking), looks like this is the way forward for me.

Now...time to find some nice rods... :p
Stock 2ZZ rods are really beefy -- I don't think they'll be a problem. The wink link always seems to be the pistons, which then can also destroy the bores -- as I've learned first hand :wtc:
 
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