Tuning Issue

Well as many of you know im now boosted. i was running 12 psi with afrs in the low 12s tuned with an SAFC. Last night i put in my manual boost controller and set it to 15 psi and it was fine that drive. i drove it last night on the highway and went to pass a slow car in 5th gear and floored it to see how long it took to get 15 psi and while watching this i watch my gauge hit 15 hear the gate open and then watch the afrs go from 12-14.5 in a split second so i let out instantly, i was tuned at +35 across at 3600 and up so i went to +45 and nothing changed same thing. went to +50 which is the max on an SAFC and still nothing. I should not be out of injector at all and if i were i would expect to fuel cut so its either the ECO wont let any more fuel be added or doesnt know what to do with this much air. any insight would be great as if i cant fix this soon im gonna have to take my bare DOHC head and throw it together and swap to DOHC with a 95 eprom ecu which i dont want to do right now as its my daily and i have school starting next week.

thanks in advance for any help

Double check your open loop maps. Make sure it targets your afr to tps %/load. Did you resec the bov back to the intake after maf? Check your knock count also.

Safc is garbage... Swap the roms, or switch to the evo 8ecu. A few 2g guys have been doing this aleeady

-Roman

I'm going 2g EPROM with the dohc but 7g guys don't have the luxury of flash able roms and shit. I'm throwing 850s in there tomorrow to see if I can get the right numbers in boost if I can I will get 680s and retune. I know SAFC is trash but I wasnt investing much money into tuning this way as I was planing on link and the built motor.

SAFC is a good tool for beginner setup. I still rock mine and I like it. The SAFC wont handle anything more than 550cc or 50% above stock injectors, thats why you can add or take fuel to 50. Id assume you calibrated the TPS setting for closed throttle and wide open throttle in SAFC. Also, what are the LOW Throttle and High Throttle switch points?

Other than that I can think of not enough fuel coming from the pump or low fuel pressure at the FPR.

Also keep in mind that its not the psi that matters that much, but the cfm's that the turbo can push. 450cc can handle 15 psi on 14b or 16g, but i cant say much about 20g. Never dealt with one. If you can log with EvoScan and see your injector duty cycle while its leaning.

Turn the boost down to 12psi and see if it does that.

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Originally Posted by mko

SAFC is a good tool for beginner setup. I still rock mine and I like it. The SAFC wont handle anything more than 550cc or 50% above stock injectors, thats why you can add or take fuel to 50. Id assume you calibrated the TPS setting for closed throttle and wide open throttle in SAFC. Also, what are the LOW Throttle and High Throttle switch points?

Other than that I can think of not enough fuel coming from the pump or low fuel pressure at the FPR.

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Wally 255, aero regulator evo 560s right now, i have room to tune out at idle and cruising for 650s or 680s. throttle points are 10 and 25. i think im out of fuel cuz if i add 35 on the safc it yields the same results as +45. gonna put in some 850s we just took out of the 1g and see it i can get the boost AFRs right. If i can then i know its injector size if not its the ECU and time to go DOHC in the very near future

850cc is unnecessary, your current setup should handle 15psi on any turbo.

Just to make sure that the fuel pressure is at 48psi with the vac line pinched, right.

The throttle switch point are wrong.

To determine Low throttle point - cruise in 3rd or 4th, slowly accelerate and watch the boost gauge and SAFC's TPS %value. You're looking when the needle reaches the zero mark on the gauge and the look back at the SAFC and see what is the TPS value in % (not in volts). I forget what mine was right now.

For High throttle point add 30-35% more on top of the determined low point.

that wouldnt make it go to 15 afrs at 15 psi tho correct? i know 850s are unnecessary but its the only larger set i have as this is the smallest turbo setup.

i will mess with the throttle point but i have it set that way as anything over 25% spools this thing and the AFR are fine, no bogging or leaning out.

it wont. i know you're trying to keep things rich so it doesnt blow the engine up, but you're dumping the high throttle settings at 25% throttle where that should happen above 50%. You are gonna have terrible gas mileage.

Throttle points were 25 and 50. I put the boost back to 12 psi and it's better. One thing I noticed is that when I first hit full boost my afrs go to low 13s then by 4800 back to low 12s and by 5500 is settles to 11.1 which is where I wanna be. +50 across the board after 4000

Tune the SAFC with a 2BAR MAP instead of the TPS, you will have better control of the fueling.

honestly it could be the SAFC. I had horrible results with my SAFC-2 when i was boosted on a 94 ECU. i could go from -50% to +50% at any rpm and it wouldn't make any difference. it led me to getting frustrated and going back to stock for the time being until i could make a better plan.

i feel like the SAFC is hit and miss with our ECUs. some people have great results; others, like myself, could never get a reading off the wideband that was acceptable let alone preferable.

It seems I can adjust cruise fully, wot until full boost then after 4800 the afrs settle nicely. I guess it could the the safc itself but it seems more like the ecu. My ecu is Cali spec and may be messing with me.

The system tricks the computer how much air is coming in. You better off with a different computer. I would do what roman said. Get a 3g computer with a evo rom. Or a full blown evo ecu.
Any adjustment made to the maf is critical.

Is not about the system. You need be a really good tuner to get everything balance like you want it. Injectors latency, timing, open loop, and other tables maps need to be adjust it right in order to get things running specially with older roms like the H8

I know how to tune. I had evoscan and ecu flash for years and have tuned many cars with link. The safc is a decent tool and I know how it works just a funky issue where from 3600 to 4800 the afrs are a little high. I'm going 2g EPROM and link when I finish the new motor until then this is what I have.

It's just about 1200 rpms under WOT that won't tune correctly and was mainly looking for people with a similar issue and I did. Thank you for the post peano.

Im not saying you dont know how to tune. Im just saying it needs more tuning work.