RB25DET AFR

[DrifterProdigy85]

After fixing my boost leaks and exhaust leaks, ive finally gotten a solid AFR reading. Currently its 11.5 AFR @ 10psi and 12.5 AFR @ 13-14psi. Is 12.5 AFR still safe with the stock ECU?
Modified by DrifterProdigy85 at 8:52 PM 10/1/2007

[rb25drag]

12.5 is lean.

I wouldnt go past 11.5

Have you turned the fuel pressure up at all?

[lilskyline240]

how are you goin lean at 14psi? alot of ppl run 13-14psi on stock ecu and are fine?

[rb25drag]

how are you goin lean at 14psi? alot of ppl run 13-14psi on stock ecu and are fine?

Its not hard to go lean, My motor is fully built and im lean at 10PSI stock ECU, and fuel pressure is bumped to 58lbs, If I go over 60lbs it wont idle period. Stock ECU sucks, gotta fork out the extra cash to get a stand alone. Its the only way to get more bang for your buck.

[lilskyline240]

thats cuz you have problems. i was in your thread

Its been proven time and time again. ive seen tons of ppl on stock ecu stock turbo running 13-14psi with no problem

[DrifterProdigy85]

Im thinking the stock ecu just doesnt have the mapping for what the airflow reads at higher boost. So it naturally will run leaner since its not putting more fuel in. 12.5 is on that borderline but its hard to say how bad it is cause the stock ecu probably doesnt have aggressive timing maps. So it might not hurt anything. I dont hear any knock but then again i run a Buddy Club exhaust which makes it hard to hear the little things.

[wawazat8402]

I run 11.8 in boost. I wont push it much leaner than that.

[DrifterProdigy85]

Ok. easy fix is that im taking the SAFC off my SR and putting on my RB to richen the system. Untill then ill leave it @ 7-10psi since thats safe. Everyone needs to stop the arguing, its really pointless and not getting anywhere from it. Its certanly not worth spending the money for a standalone and tuning on a stock engine that im not gonna modify much more than it already is.

[digzsublime]

Sounds like a good plan. Although, if you turn the boost down a bit, you may notice the AFR's come back in line. Then you wouldn't even really need to mess with the SAFC.

I have the SAFC on my RB20. But, it's basically only there to control the Z32 maf. If I didn't need it for that, I probably wouldn't use it much. I wouldn't really even need it for that if I hadn't put my thumb through the top of my RB20 MAF.

G/L with everything.

[Joe]

I personally Emailed Carl and asked him to lock it.

its not your thread to have locked man. you are the one that **** on it

you guys are being idiots, both of you.

Ok. easy fix is that im taking the SAFC off my SR and putting on my RB to richen the system. Untill then ill leave it @ 7-10psi since thats safe. Everyone needs to stop the arguing, its really pointless and not getting anywhere from it. Its certanly not worth spending the money for a standalone and tuning on a stock engine that im not gonna modify much more than it already is.

the easy fix is not always the correct fix. i hate SAFC's with a passion. they are a half assed bandaid to a problem.

you arent running that lean. for a bone stock engine i wouldnt worry too much about 12.5:1.

[sleeper101]

Hey guys im new on here just thought I would get in on this.

AS my experience with the AFC and PFC.

The AFC is a temporary fix for a stock ECU, you can get closer on the tune but your not going to be able to tune good enough to get good throttle response to oppose to the FPC. The PFC lets you hit the tune right on, dead nuts, on my setup I was running 285HP with the AFC, fully tuned, Switched to PFC on same setup and same boost 10PSI @ 20 degrees timing and was able to gain 30.2 HP went to 315.2 just by switching Ecu's.

So you can look at the ECU as a power gainer to not just another electronic device. I was impressed with the HP gains. Hope you have the same luck man!!!

[DrifterProdigy85]

Did you increase your base timing from 15* to 20*? Or are you running 20* of timing for 10psi?

[sleeper101]

I increased the base timing, The RB seems to love timing down low. It really gives it alot better throttle response. Also wat I thought use to be turbo lag I dont really have any more. It seems to pick up instantly since I have a good tune. I think its just all that fuel being put in there in low rpm that really doesnt need to be. With the PFC I am able to put any amount of fuel and timing at any point I need to. Whether its down low or up high. Really nice setup. Well worth the price in my opinion.

But also if your going to run that much timing be sure to run a cold plug to keep from detonating. I personally am running a number 4 cold plug. A/c delco. It seems to run really well. I have tried the NGK's but they really didnt give me the same throttle response, It seemed to pick up alot more on bottom end. Also the A/C delco's are half the price.

[DrifterProdigy85]

I running NGK Iridium 6's right now. Since you just increased the base timing, that can be done without the standalone and as far as adjusting fuel at all points needed, the SAFCII will do the same thing. I just might try this. Bump timing to 20* and then use the SAFC to tune for 11.5 AFR. The RB25 has a knock sensor right? Ill keep tabs of knock via SAFCII and should work near the same. The only difference is probably gonna be the PFC RB Base Maps is better than stock.

[sleeper101]

YA the RB has a knock.

The only problem is the timing is still going to jump around on ya due to the mapping of the stock ECU. But you will be able to get that AFR down with the AFC.

Let me know how it works out.

[DrifterProdigy85]

AFR isnt very irradic right now. Once 4krpm hits, it runs a solid 11.5-11.6 all the way to redline with 10psi.

[silviasgp06]

I running NGK Iridium 6's right now. Since you just increased the base timing, that can be done without the standalone and as far as adjusting fuel at all points needed, the SAFCII will do the same thing. I just might try this. Bump timing to 20* and then use the SAFC to tune for 11.5 AFR. The RB25 has a knock sensor right? Ill keep tabs of knock via SAFCII and should work near the same. The only difference is probably gonna be the PFC RB Base Maps is better than stock.

im still learning about the PFC but are you saying that the base map will work perfectly until one has the cash to get a full tune?

[DrifterProdigy85]

It should run like stock as long as the setup is similar to stock. I never had a PFC yet but i always thought the Base Map is basically a stock map used to make any modifications neccessary to.

[lilskyline240]

yes, the base map should be the same map as the stock ecu

[spoolin_s14]

actually the powerfc base maps are slightly better than the stock one's. from what i've always understood pfc should give you 5-10 hp just by plugging it in

[DrifterProdigy85]

Bringing the thread back because i got the car pretty dialed in. Did a test & tune session tonight on some back roads. Started raising fuel pressure untill i got it to run 12.0 AFR from 3k-6krpm then it richens to 11.0 AFR. Pulls very hard now. What i said before about the AFR reading lean at higher boost is wrong. It was reading lean at all boosts and then richening near redline. So now it reads a solid 12.0 and drops to 11.0 at redline. For some reason the car starts to misfire pretty bad though when i run .9 Bar but when i run .75 Bar it runs perfect. There brand new NGK Iridium 6 plugs gapped at .030" so i dont know why they would be missing. Wonder if i need NGK 7's for the higher boost.

[lilskyline240]

try gapping them smaller

[DrifterProdigy85]

Ill try .028" when i get a chance.

[DrifterProdigy85]

Drove the car some more tonight. Starting to miss with 10psi now above 5500rpm. Its getting really rich like below 11.0. Put it on stock boost and did a 3rd gear pull, it starts out reading 12.0 @ 4krpm and gradually gets richer as it approaches 6krpm. Which its about 10.8 @ 6krpm. I need the SAFC real bad. Stock ECU fuel mapping sucks. Might pull it off my SR tomorrow. Hopefully it wont need it.

[silviasgp06]

what do you mean you hope it doesnt need it? are you talking about the sr that the sacf is comming from? if you are then you should know if the safc is tuned to the motor and its mods or not. dont mess up one car if its running perfect just to get one to run stronger on higher boost. keep boost low til you get another safc or a standalone, then tune.

[DrifterProdigy85]

My SR runs a Enthalpy Tune. I just have the SAFC on there in case the tune would be off. I just had the motor rebuilt and a new tune but i havnt driven the car yet to find out how its gonna perform. Im just gonna take it off and put on the RB and if the SR tune is off, ill go to Power FC for it.

[lilskyline240]

did you gap them smaller? if so now your running richer? try putting your fuel pressure back to stock to see if you still have your problem. Also have you checked for boost leaks?

[DrifterProdigy85]

Still at .030". No Boost Leaks. I put the SAFCII on today. Ill work on tuning it throughout the week as i drive it.

[DrifterProdigy85]

Also gonna check the timing sometime soon. I wouldnt doubt it to be off. Just have to wait while finishing my SR. Also, whats everyones rev limiter on the RB25 stock ecu?

[rb25drag]

How much fuel pressure are you running? Whats the timing set at?

.030 should be the correct gap.

Using the AFC you should be able to lean it back out.