BigDogJonx

iTrader: (7)

Well pushed it from 5psi to 10psi today. Also wired the SAFC2 for the dyno tune tommorow. But something wierd is now happening. Everytime I floor it and see the boost go to 10psi, the car acts like it is stalling, it just and going. Tried it again, same thing. If I keep the gas steady and dont push it past 5psi then it acts like it used to where it just takes off like normal.

I have a 10:1 disc in there now, so dont think im running into any issues of not getting enough fuel. I got a walbro 255lph in the tank so cant be the fuel pump.

Anyone got any ideas?

BTW the SAFC2 is all zero right now except the standard settings of 39% and 40% low high points. 4 in 4out. Hot Wire. 6cly Arrow pointing up.

Dixit

Confused

iTrader: (4)

injectors are maxed out.

BigDogJonx

iTrader: (7)

Ahh shiet, dont tell me that. 10psi and maxed out? I know Kev is running a larger turbo at 10psi and dont think he has had any issues.

If they are maxed out, this is going to suck.

Dixit

Y2KevSE

iTrader: (13)

10 (psi) X 10 (to 1 disc) + [34 (base pressure) / 2] = 117.5 psi

I have 0 problems going to 10 psi. The 5th gen injectors are larger... either 249cc or 259cc, so I don't believe you've maxed out yet. It might be possible that you are flooding the engine with too much fuel though. With SC 10 psi on 8:1 disc, I was running lower than 10:1 A/F after 5K... so I can't imagine what you would be doing with the 10:1 disc.

BigDogJonx

iTrader: (7)

See I met with Matt (mardigrasmax) earlier and asked him if maybe my disc would be too large. He said should be no issue since the FMU is boost relative. I told him about "what if my 10:1 is too much and my SAFC2 cant lean it out enough?" He said not to worry cause it is boost relative. But I do kinda understand what you are saying about the disc being too big and maybe flooding the engine.

Problem is that I dont have an 8:1 disc, I gave all that away with my s/c and didnt think Hal was going to use the same Vortech FMU. I shouldve got a Cartech where I could just turn the screw and not deal with this crap of discs.

Man only time will tell at the dyno tune tommorow. I might have to drop it to 8psi and then tune at there.

Dixit

Y2KevSE

iTrader: (13)

That sucks.

I believe you will still be running rich with it on 8 psi unless somehow you made an enormous amount of power to use up the fuel..... otherwise, the engine will flood.

Put it on the dyno and see what you come up with tomorrow. Good luck and I hope you put down some nice numbers!

BigDogJonx

iTrader: (7)

Well I dont think the shop is going to have a 8:1 disc cause he doesnt use Vortech FMUs, I dont remember what he uses. I wish I wouldve kept the extra 8:1 disc.

Dixit

Chunger

iTrader: (1)

I think Brett meant they may have "locked up" due to the extreme fuel pressure... Your turbos spool up to full boost way before redline.

turbo97SE

iTrader: (3)

I think Kev is probably right. I have a 12:1 FMU disc which is BAD for mid range but helps on the top end to prevent leaness!!! When I hit boost the car bogged a lot without tuning and black smoke poured out when that happened, so watch the tail pipe or have someone watch it for you. I had to back the fuel waaaaaaaaaaaaay down with my SAFC. On the dyno I made 20-30 HP from just backing that off in that rev range. I am still a little rich but much better than I was. I haven't put my Cartech on yet but I would recommend it cos it is so adjustable!

If you played with the dec-air stuff, reset it for now since it will hesitate at lower throttle if you set it up wrong. Doubt it is this cos you said it happens when you floor it.

I doubt that your injectors are maxed out, you'd be lean and pinging then.

Good Luck!

Nigel

hlh0501

iTrader: (1)

I hiiighly doubt it is injector's, I have run 12:1 disc @ 13psi before... i know, verry scary fuel pres, but nonetheless. This also makes me think you aren't "flooding" it completely, because even as rich as it may have been w/ 12:1 @ 13psi, it still ran beautifully.

First thing I would do, pull the harness from the safc, completely disabling it. Then see.

MAXIN

iTrader: (5)

ok, u guys just lost me....

1)Arent the FMU's rising rate, where as boost increases fuel psi increases? So why would a 12:1 be too much if its boost dependent?

2)What makes the cartech set at 12:1 different (besides the adjusting screw) compared to a vortech FMU at 12:1? Can the rate(speed) at which fuel psi rises be adjusted as well?


sorry 4 gettin a lil OT dixit

Y2KevSE

iTrader: (13)

Check out my FP calculation up at the top. 117 psi is WAY too much... I ran 105 psi with the 3.125 pulley which put out 284 (untuned). The FP dropped below 10:1... I'd imagine Dixit putting about the same hp with the car untuned, so think about how much extra fuel he's NOT burning up.

FP calculation for 12:1 (at 13 psi) is... 173.1 psi = problems.



12:1 vs. 12:1... doesn't make a difference. The reason why you want the Cartech is because it is adjustable (no need to swap discs, just turn the flow rate ****).

MAXIN

iTrader: (5)

gotcha kev, thanx for clearing that up.....

John at J&S

If the fuel pressure gets too high, the injectors can't open. I think that's what's hppening.

Jeff92se

iTrader: (82)

Either get on a dyno w/ the wideband or maybe have an exhaust temp guage hooked up to monitor the temps.

BigDogJonx

iTrader: (7)

We did do this Saturday. We noticed we were running lean like 14.5:1 on the dyno at just 7psi on a 10:1 disc and tried to lower it but I think we are running into some type of fuel problem or injector maxxing out.

Dixit

Y2KevSE

iTrader: (13)

http://forums.maxima.org/showthread.php?threadid=197450

Jeff92se

iTrader: (82)

Can you guys get one of those OBDII readers that uses a Palm? If it has injector duty, you might be able to see if the injectors are going over 80% duty cycle.

Are your exhaust temps going sky-high? If so, I would say you are going way lean. If they are low and you are getting a big bog, then I would say you are rich.

I think someone said if your dyno is really choppy, it's a sign that the injectors are maxed out and is pulsing erraticly(past their efficency rating)