Mad-MAX_SE

iTrader: (2)

I really didn't want to post a new thread, but since this is still a fairly rare thing to do I'm having a hard time getting the answers I need.

I currently am running a 10psi (3.25) pulley on a V2 setup on my 3.5 with a walbro 255, DE-k injectors, FPR/FMU and I have a couple issues.

First: The car is starting to run lean about 4500-5000rpm. I first thought that I might be maxing out either the injectors or the MAF. Based on the output from the VAFC, the "pressure" reading seemed to stop in that area (hence my thought the MAF was maxed out). I just installed my Z32 MAF, haven't had a chance to take the car out due to family stuff today.

Second: I was reading over several threads to see whether or not my injectors can support the 10psi or not. I know it isn't ideal, and the pressures are getting up to the 75psi range, but from what I can tell they should support 10psi at that fuel pressure. I was wondering if maxing out the MAF would cause the lean condition or if it was truly a combination of undersized injectors and maxed out MAF.

This last part might be a "duh" question, but I'll go ahead and ask anyways. By changing my VAFC settings to go from the Z32 MAF to A32 MAF, will that help with a maxed out MAF? I mean, if it's using a voltage interpolation between the two, am I actually gaining the ability to meter more air to the motor?

streetzlegend

iTrader: (8)

You already gained the ability to gain more air by putting the z32, so no need to go with a32 settings. (unless i didnt understand your question)

It is possible that you were running lean because of maxed out maf, once the maf no longer reading higher voltage, then anything above that max airflow is not going to be taken into account by the ECU, therefore no additional fuel would be provided. However, even if a maf is maxed out, you can still add corrections ontop of it, now you have a z32 so thats good. As far as injectors, I really dont know, but just dont try to test your luck with small injectors, id get bigger asap.

JAMAICANLOVRBOY

iTrader: (3)

i have six toyota 370cc injectors (i went 440cc), they are side feed not sure if they would work for you, but you never know

aic96max

iTrader: (12)

this site helps at times

http://www.witchhunter.com/injectorcalc1.php4

looks like 290 ccs will be at 100% duty cycle at about 275 flywheel hp, so if your not maxing them out, then you arent making the power. excessive psi will help run that number up a little. another way to help add fuel is meth injection. id also recommend injectors asap

MaximaSpd85

iTrader: (14)

^whats that mean? the injectors max out at 275 flywheel hp? almost all modded 5.5 gens make way more than that on stock 3.5 injectors so i dont see that. or maybe i understand that wrong...

aic96max

iTrader: (12)

check the link, injector size is calculated diff for na, sc, turbo.. diff *

* Brake Specific Fuel Consumption: is the amount of fuel consumed (in lbs. per hour) for each horsepower made. This should be .45 to .50 for naturally aspirated engines, .55 to .60 for supercharged engines, and .60 to .65 for turbocharged engines.

as used on this calculator for an na car @ 100% duty 290s can in theory be maxed out arouund 350 flywheel, and usually its recommended to run 80% duty max

"way more" ???

Mad-MAX_SE

iTrader: (2)

Yeah, but that is based off static fuel pressure of 3.0 bar, when you're running a FMU and raising the pressure to roughly 75psi, things change...

If you use the CC rating at a given pressure (295cc@43.5psi) then put it into the lower formula on the page at the peak fuel pressure it will give you a more accurate idea of what CC's the injectors are flowing at that point...

You had the right idea aic996max, you just forgot about the other part of the equation.

My fuel setup can basically handle 360chp, and at 10psi I'm either very close or surpassing that mark... edit: I should be well beyond that (was thinking wheel HP) or i will be disappointed...

aic96max

iTrader: (12)

this is a well known fact, i have seen people run crazy psi, via fmu, i guess log with the new maf and take it from there. have you gone through dynos and seen where others runs these out?

MaximaSpd85

iTrader: (14)

dang it, i overlooked that asterisk for the n/a guys lol. my bad

way more? idk, i figured theres a lot of modded guys at 250 whp or more, thats a bit more than 275 flywheel hp. fine, not way more, but more for sure.

aic96max

iTrader: (12)

youre right, forgot to that part. looks like it says 370 @ 75 psi and 100% duty cycle. thats flywheel hp. not sure about sc, but i know a tc 3.5 makes that kinda power @ 5 psi so you may be there, let us know how the logs look, bc based off what streetz has mention iirc thats about when the stock maf gives out also.

aic96max

iTrader: (12)

yea i heard one dude running 290 whp so yeah they def have more in there for na

Mad-MAX_SE

iTrader: (2)

I guess the ideal injector size would be in the 440-500cc range. 440's are readily available, however, the next size up I have been able to find is roughly 600cc's. I honestly think that might be overkill. I know that in the past, using 510's with a Z32 MAF basically got rid of the need for a FPR cause of how close it is to double everything stock on the 3.0's. 600's would allow me to lower my FP to like 30psi and lower my rise rate to about 2:1 versus the 5-6:1 I have it set to now. 440's are still more than adequate, just requiring a slightly higher gain and a little bit higher base FP. My concern is what kind of HP is the car putting out. Meximax's car put out 440+whp @13psi on his setup. I would venture to say that I should put out somewhere in the 350-370whp range @10psi (if not slightly more) which correlates to approx 450ish chp. The 600's would really only need a FPR to maintain that (assuming it can handle a 1:1 rise rate with boost). A FMU would help in allowing the base fuel pressure to be lowered and still build enough pressure (roughly 55psi for ~475chp @ 80% DC, 65psi for 70% DC) for the top end.

Guess, going by that logic, not only are my injectors maxed out, but i need ones twice the size to even be safely on track...

Mad-MAX_SE

iTrader: (2)

This project is getting really freaking expensive at the end...

nismomaxct

iTrader: (24)

Welcome to the world of boost. Everything ends up costing much more than expected. I might have a set of 440cc's for sale. I will know more tomorrow.

t6378tp

iTrader: (69)

If your lookinh to make over 400hp then just get some 600cc injectors and ditch the fmu

t6378tp

iTrader: (69)

Forgot to add sc setups require more fuel than tc setups at the same power level due to the extra hp needed to spin the sc

Mad-MAX_SE

iTrader: (2)

let me know
I'm hoping to make about 350-375hp. Based on the calculator, I'll still need a FMU to keep the duty cycle down on the injectors (and being that my FMU is built into my FPR, that it isn't an issue).

t6378tp

iTrader: (69)

You won't have duty cycle issues with 440 or 600's with a 1-1 rate

Forcing smaller injectors to spray more fuel by increasing the fuel psi is not the ideal way to make power

Mad-MAX_SE

iTrader: (2)

Yeah, i know. I'm thinking 440's will probably be adequate. Meximax was using 440's and pulled over 400whp. He had some leaning out in the upper RPM's at ~65psi of FP, but I'm not pushing 13psi like he was/is and don't mind running ~70ish psi of FP.

Hoping Nismomaxct will get back with me about his injectors. If not, I'm going to go with some new Deatchwerks 440's, since the price is pretty reasonable and it's a company I know has great products.

Only part that kinda sucks is I'm going to have to hold off on an EU for now. I can afford one or the other before I go to the dyno on December 11th, just not both... Hoping I can talk NCSU_Max into letting me borrow his EU till after Christmas (and buying the boost and AF option wires...) till I can get my own.

mastercater7

iTrader: (2)

Welcome to the S/C 3.5 world, it is definitely not a cheap setup to maintain. I would recommend going with the Deatschwerks 600's, that's what I am running. I also have an AFPR instead of an FMU, I have never used an FMU but I will say that when tuning the AFPR is a great piece to have. I keep my fuel pressure at 43.5 at idle and everything stays in line through the rpms. I am also running the 2.87 pulley. Are you running a 3.0 idler pulley or a 3.5 idler?

Mad-MAX_SE

iTrader: (2)

I'm not currently planning on going above 10psi (3.25 pulley) with this motor just yet (stock head/rod bolts). It's already a handful at 8psi (since I can't really red-line the motor until I get bigger injectors...) so I think 440's should be fine for now. I have an AFPR, it's a rail mounted unit by Synapse that has an integrated FMU. It has a simple adjustment **** that allows for fine tuning from 2:1 - 12:1 rise rates (or disconnect its vacuum source and it's 1:1) and can adjust static FP from 20-100psi.

As far as the idler (I think you mean tensioner...), I'm running a 3.0 tensioner.

Mad-MAX_SE

iTrader: (2)

Update:

I just got in some 530cc injectors, and have a few questions still. I tried setting the MAF to 2in/2out and it won't idle at all, tried changing the output from 4 to 2 after the car was started and as soon as I got on the gas it leaned out like crazy. Tried 4in/4out, same deal. 2in/4out works great but I'm still maxing the theoretical voltage of the A32 MAF so I still have the lean condition in the upper RPM. I figured, according to this post I30tMikeD - 550's, Z32, Stock ECU, I could change the in/out settings from the current 2in/4out to 4in/4out and due to the size of the injectors and be back close to a stock AFR.

Anyone have any ideas?

Mad-MAX_SE

iTrader: (2)

The only logical explanation is that the injectors aren't what I was told they are. I would have predicted a very rich condition on initial start-up using the same FP as before on my DE-K's, but there was no change (as if there wasn't any more fuel flowing from the injectors than before)...

nismomaxct

iTrader: (24)

I sent you a PM.

Mad-MAX_SE

iTrader: (2)

Ended up having to order 600's from Deatschwerks, and they're fantastic. I think the guy I bought the injectors from either got lied to when he purchased them or accidentally sent the wrong ones to me. Either way, they weren't/aren't 530cc.

Going to the dyno tomorrow, we'll see how she does

MIKERNM1990

i hope u'll get over 400 whp or engine build 450 whp?