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Vortech still running lean, need to get Adj FMU on a budget need ideas :)
hi again everyone, First off I wanted to say thanks to everyone before who helped me with my Vortech and Vafc-2 problem last week. Once again I headed out to get my SC tuned and what do ya know its running SUPER lean, right after 6k RPM my af its like 15.01. Church was able to help me tune the Vafc to about 14.33 which is still too lean. The limited tuning he was able to do gained some hp and tq at the top end but i lost some in the bottom and mid range.
My problem is i'm looking for an aftermarket adj. raising rate fuel regulator to replace my stock vortech FMU that isn't that expensive. The Vortech SFMU costs $306 and a bit much for me right now. I found a B.E.G.I. regulator but they cost around $260 and i hadn't found any S2k's that have tried it and used it to see how well they work.
I know my last alternative is to get the 12:1 recalibration kit and try to retune it with that. but i was hoping on finding an adj. one that isn't going to cost much over $200.
Any ideas on what other brands i'm overlooking or should be looking into? Thanks again ;D
Sounds like you have done your homework on FMU's. The only other company that I know of that makes one is Jackson Racing, But I don't know what rate there unit is. You may be able to pick one up used, as lots of Jackson owners remove them and add big injectors/hondata.
I don't know if a different rising rate FMU is going to help you. The 10:1 FMU Vortech provides with the kit is allready at 125psi @7.5psi of boost. Even with a different rate FMU, the limiting factor on how much fuel is entering the engine is the injectors. (which were never meant for fuel pressure that high) The problem with high fuel pressure, is that as pressure increases, volume decreases. The injectors are also not able to effectively close, but are "blown" open by the high fuel pressure.
It looks to me the best answer (most $) would be to add AEM EMS, But the EMS is not a perfect system. You are lucky that you can use Church, who has been the best AEM EMS tuner for the S. Other options include the E-manage. (also not perfect)
What did UL reccomend for you to do?
With the AF that lean, I wouldn't go exploring past 4000rpm any time soon.
he suggested that i get either a new disc for the vortech fmu, which he says 12:1 should do since it adds about 20% more fuel. or an adj regulator. Which is better since he can tune it more precisely. i figured an adj would be the better option but seeing how expensive they run. i wasn't sure if there were other brands i could consider. I had considered the Emanage and AEM originally but due to the high costs on those components right now i can't really afford to go that route.
yep i know i need to bring my a/f down. he said i would want it to be around 13.1. he said just about every Vortech he's tuned has come up lean. I had figured Vortech to fix the problem with so many previous systems sold that were showing to be really lean and that i would be lucky to actually run fairly normal but no luck.
but before i went and ordered the 12:1 recalibration kit, i wanted to see if there any other option that won't cost that much.
If your problem is not enough fuel and your injector duty cycle is not too high I would suggest an E-manage (predictable huh?).
For about $400 (cheaper used) you should get the E-manage and injector harness which will let you drive the injectors a bit longer in the higher revs. It can also replace your MAP limiter and do some ignition control but it's not necessary.
The AEM EMS is a better option but at 3 times the price a bit hard to justify.
H9K, Your math is a bit off. The stock fuel pressure with the FMU installed is about 50psi, at idle. Fuel pressure without the FMU is lower, around 40psi. The FMU adds a restriction and increases pressure. With a 10:1 FMU, fuel pressure is 125psi@7.5psi of boost. 50+10x7.5=125psi.
12:1 FMU =140psi@7.5psi of boost.
13:1 FMU =147.5psi@ 7.5psi of boost.
thanks everyone for your input , because i've already invested in the vafc, and can't afford to go emanage or aem,i'm going to try the SFMU, to increase the basic static fuel pressure, lower the raising pressure from 125psi @7.5lbs of boost to around 100psi. it sounded like that's what the SFMU can do for me hopefully. another user on here is selling his with the fittings. it's so complicated but i'm learning as i go. and have a much better understanding of the fuel settings on FI cars. What do you guys think? would it be ok for now?
if you go with the SFMU, I'd get it dyno'd with the wideband while setting it. It may work, but I don't think anyone here has tried. Post back if you get the AF in a safe range. I'd be interested.
Look at your A/F graph; it's all over the place. All you can do with an FPR is raise or lower the whole line (by changing static pressure) or change the angle of the line (by changing the ratio). Nothing you can do with an FPR will smooth it.
To do this properly you're going to have to spend some dollars on tuning regardless of the method.
06-07-2004, 01:44 PM
Vortech still running lean, need to get Adj FMU on a budget need ideas :)
sorry got distracted with work
, because i've already invested in the vafc, and can't afford to go emanage or aem,i'm going to try the SFMU, to increase the basic static fuel pressure, lower the raising pressure from 125psi @7.5lbs of boost to around 100psi. it sounded like that's what the SFMU can do for me hopefully. another user on here is selling his with the fittings. it's so complicated but i'm learning as i go. and have a much better understanding of the fuel settings on FI cars. What do you guys think? would it be ok for now?