New dyno and Injectors question

[The__J__Factor]

Ok so after last weeks dyno attempt went badly, kept blowing off pipes and the bov wouldnt open.
I went and replace most of the silcon joins to higher quality ones and went and replaced all my ****ty worm clamps with t-bolt clamps. That fixed that problem.
Went and bought a bosch bypass valve to replace the turbo smart bov. Problem solved.
Went to an exhaust shop and changed the flex pipe that came with the PPE header which had shrunk a good deal. Sounded much better and ended up helping alot on the dyno.

So after all that, we went from last weeks reading of 250whp at 8000rpm, no power tuning coz the piping wouldnt hold.

Today we did about 8runs all up, not much tuning at all coz we maxed the 530cc injectors out at 7900rpm.
Ended up making 281whp at 7900rpm (this is the where the rev limiter is set to make sure we dont kill the injectors) this is about 70hp more then the original dyno reading i got a long long time ago when i only made 7psi so we are heading in the right direction and im pretty happy.

This dyno is supposed to be notorious for reading real low, but heres the print out. As you can see we didnt do much tuning evident in the bumps ect in the power curve. Looks like we will make great power once i get new injectors and up the rev limit and finish tuning.
http://img.photobucket.com/albums/v508/The__J__Factor/281hp-Dyno.jpg

270hp run
http://img.photobucket.com/albums/v508/The__J__Factor/th_270hp.jpg (http://smg.photobucket.com/albums/v508/The__J__Factor/?action=view&current=270hp.flv)

281hp run
http://img.photobucket.com/albums/v508/The__J__Factor/th_281hp.jpg (http://smg.photobucket.com/albums/v508/The__J__Factor/?action=view&current=281hp.flv)

So question is, will going from 530cc upto 630cc injectors be enough to handle the extra say 40whp? 40whp is just an optimistic guess, i want to make sure the new injectors will be more then enough for what i make. 300whp looks pretty certain.
I also have a walbro 255 fuel pump.

[lVlemphizStylez]

I run 630's on my car and it's well beyond 300 whp, near 400 whp. So the injectors are good for it. 530's might run out of steam, maybe not. someone else might have to answer that. I used 550cc's for mid 300's at the wheels

[grumpy]

I've got 630's and a 255 Walbro pump that was shimmed. I ran out of fuel before it was shimmed. I topped out at 8500 with 300RWHP or so after it was shimmed and have 78% duty on the injectors after it was shimmed. Before it was shimmed it was high 90%'s, 98%or so IIRC. I didn't dyno it without the shims. Didn't make sense when I was out of injector. A return system would work also.

[lVlemphizStylez]

what 630's did you have?? what psi are they rated at?? mine support up to 450 whp rated at 636cc at 3 bar

[jlitman]

You should be fine with the 630's.

Is that second line torque?

[The__J__Factor]

The bottom line is Boost.

Im beginning to think 630cc wont be enough. Does any one know how much more hp 630cc would support over 530cc?

[jlitman]

You can get a reasonable estimate here

http://www.rceng.com/technical.aspx

Don't forget to deduct boost pressure from your fuel pressure... the former fights the latter.

You'll probably easily break 300 whp revving to 8.5K :D

So, how much torque did you put down on that last pull? :wiggle:

[Jesse IL]

I run 630's on my car and it's well beyond 300 whp, near 400 whp. So the injectors are good for it. 530's might run out of steam, maybe not. someone else might have to answer that. I used 550cc's for mid 300's at the wheels
Old Hondas have return fuel systems and you're probably using a 1:1 or rising rate regulator.

[lVlemphizStylez]

yea I had an aeromotive on the integra and one now on the neon and the neon has a homemeade return system on it.

I guess he still on the returnless system, it would be more cost effective to put together a return line than buy a new set of injectors. I did the one with the neon for about 230 with the regulator (it's just a bunch of 6 AN fittings etc pretty universal sh!t). As long as he has a fuel rail with a schrader valve on it to plug into after the rail, or he could skip that and put the FPR in before it

[yankee_gts]

The bottom line is Boost.

Im beginning to think 630cc wont be enough. Does any one know how much more hp 630cc would support over 530cc?

I have a set of 750cc RC let me know if you are interested (PM)

btw congrats ;)

[GTsRasta]

x2 on 630cc injectors and a return system for the deadhead fuel supply.

Might make tuning easier too. That sounds like a winner to me. Maybe you can fab up a fuel return system on your own, and see if that'll be enough for your sub 350 whp needs. Not sure if that will make the injectors approach 80% duty cycle though. Might gatta check that calculator jlitman posted. Check out what bt216 runs for 550 whp:


Engine Management Modifications: 750cc RC injectors, MWR fuel pump 255lph, Smaay return fuel system, Apexi power full computer, Datalogit, Apexi AVC-R, AEM wideband, STI maf


Numbers like this make me exited for a certain buddy of mine getting a custom rotrex setup here in NY put into his car. Unfortunately, it'll be tuned on the AEM F/IC piggyback ECU for OBD-II compliance, and the fact that standalones are limited for his car, which still won't be that bad due to the unit's superior 02 sensor interception and MAP tuning.

[Smaay]

yep a return system will solve alot of your issues

[lVlemphizStylez]

I'm making a write up on how to do a homemade one for the celica...it'll be under 300 dollars SHIPPED with an aeromotive regulator. I'm shooting for 230 or below. I'll make a thread with the parts and pics once I take apart my gf's gas tank and see how and where the pump is housed

[Jesse IL]

I guess he still on the returnless system, it would be more cost effective to put together a return line than buy a new set of injectors.
Actually, converting to a return system is far more expensive. It really depends on what your goals are. You need to choose injectors wisely is what it comes down to and keep in mind how much boost you're running, as the more boost you run, the less flow you're going to get out of the injectors.

In this example, if he were only trying to make 250 whp, he would be fine with what he has. A set of 630's or 750's will move up his power capabilities, depending on boost of course. It gets to the point where you simply aren't going to make any more power, that's when you invest in the return system.

A return system (provided its a 1:1) will make tuning easier because you'll get a more linear response to boost (without the return system it is non-linear) but most people aren't willing to drop the money to buy one of Smaay's systems just to make their tuning easier, especially considering most people don't do their own tuning.
Not sure if that will make the injectors approach 80% duty cycle though.
It is a TOTAL MYTH that you can't reliably run injectors above 80% duty cycle. In fact, most evidence shows that in street applications, injectors are perfectly reliable to well over 90% duty cycle. That myth is based on race engines that spin to extremely high rpm's, like motorcycles and F1 engine. It is all based around the speed with which the injectors can open and close. At extremely high engine speeds, the total time for one engine revolution gets extremely short and the actual pintle speed in the injector becmes relevant. Since the off-time is so short, injectors, especially large ones, won't even close before the next spray cycle begins. That means that above certain duty cycles, the injectors actually stick open. This situation is not relevant to street engines turning 8500 rpm.

The reality is that you want to run the smallest injectors possible for your power goals. The reason why is that smaller injectors are less massive and take less time to open and close. This makes these injectors much more accurate, especially at very low duty cycles.

[Smaay]

the reason i made my return system the way it is was to make it a drop in plug and play. of course it can be done much cheaper by using your original parts.

the FPR is about 180
walboro's run about 125
still need some braided hoses and fittings that run about another 100
and my kit also included my rail

things to think about

[lVlemphizStylez]

Oh I'm not trying to sell this DIY return line smaay...Just hopefully it'll be an alternative, it won't use all SS lines either, I was going to use some 6 AN Push lock fittings and substitute some fuel hose that can be bought for like 25 bucks for 15 feet instead of SS line that's like 70 bucks for 12 feet(I used it on my car and it's oil, temp and obviously gas resistant, rated at max psi of like 125 and has been holding like a champ ). Plans are to retain the stock rail, block off the factory FPR from trying to regulate the fuel and tap into the top of the fuel canister and run the return line. Won't be 100% plug and play but anyone that can use a drill and a unibit shouldn't have a problem. I bought all my stuff from Summit racing and it comes with a 1 year warranty on all parts used to make my return line, can't beat that for 230 to my door

[Jesse IL]

I'd say 95% of the people here are mediocre DIYers at best. For those people, Smaay's system is the way to go. Smaay's system is also extremely robust, which you want when you're talking about fire hazards.

[lVlemphizStylez]

well like I said im not trying to advertise it or make money off it. I'm going to do the write up for those 5% that just look in their wallet and know they can't right now. As far as fire hazards, I don't have any leaks on mine, used teflon thread sealant on everything besides the fittings at the regulator (they have a rubber O ring on the ones I choose to use there). And on a rising rate my lines have seen about 70 psi and they are still fine

[Illusive]

Time for a return fuel system. your injectors are big enough to support your powergoals.

[jlitman]

It is a TOTAL MYTH that you can't reliably run injectors above 80% duty cycle. In fact, most evidence shows that in street applications, injectors are perfectly reliable to well over 90% duty cycle. That myth is based on race engines that spin to extremely high rpm's, like motorcycles and F1 engine. It is all based around the speed with which the injectors can open and close. At extremely high engine speeds, the total time for one engine revolution gets extremely short and the actual pintle speed in the injector becmes relevant. Since the off-time is so short, injectors, especially large ones, won't even close before the next spray cycle begins. That means that above certain duty cycles, the injectors actually stick open. This situation is not relevant to street engines turning 8500 rpm.

The reality is that you want to run the smallest injectors possible for your power goals. The reason why is that smaller injectors are less massive and take less time to open and close. This makes these injectors much more accurate, especially at very low duty cycles.
Absolutely correct. Many OEM's run them up over 90%. At 100%, there may be problems, because you want some off time is to keep the injectors from overheating. In any case, a road car isn't going to see high duty cycles for extended periods of time...

I punched in a few numbers on that injector calculator, and he should easily be able to put down 300 whp (assuming 15% drivetrain losses) with 630's and stay well under 90%.

Another reason for using the smallest injectors you can run is that the pulsewidths for a stable idle will get very low as bigger injectors are used, and the car will be more likely to stumble unless you set the idle very high to help compensate.

[GTsRasta]

The reality is that you want to run the smallest injectors possible for your power goals. The reason why is that smaller injectors are less massive and take less time to open and close. This makes these injectors much more accurate, especially at very low duty cycles.

I agree with this philosophy as well. A more calmer idle sounds better to me too.

[lVlemphizStylez]

or....with a proper return setup you can dial the base pressure out of the bigger injectors and get them to idle fine (to an extent, go too low on base pressure and you'll have some atomization issues, injectors start dripping rather than spraying)

[The__J__Factor]

Well ive probably got a bit of time to think about everything and see how much each option will cost. New injectors or return system.
I do like the idea of fabbing a return fuel system, if i buy a rail off smayy the rest i could have made here pretty easily.
The only thing i dont get with the return system is whether or not the return fuel line connects to anything inside the fuel tank or if its just tapped into the top and flows into the fuel tank.

Jlitman i have no idea what torque it makes :S I dont think we even checked, also how do dyno runs get saved? is it like a .achieve file where it stores all info about the run, ie HP, torque, Boost, Air/Fuel. Or does it only save whats displayed?

Thanks for the help everyone, 300whp looks very easy - the power is building up fast uptop and with extra tuning i want to hit around 310.

Anyway im pretty happy right now, so off to enjoy the car!

[lVlemphizStylez]

you can run the return into the canister where the fuel pump sits or you can just dump it back into the tank...either works but the other makes sure the pump canister never goes dry (may or may not be an issue on the celica, but was one on my car, I would get infrequent lean hiccups during cruising when the load on the pump wasn't high)

[The__J__Factor]

Just bought a smayy return fuel kit off a forum member for a very nice price :)
Hopefully thats all i need at this point.

Probably wont be going back to the dyno for another month or 2, uni holidays are over and ill have no more money for it.