safc and t25 tuning

[calreef18]

Hello all, I was looking for any advice on starting trims for using a safc on a t25. Currently my mods are an intake, mbc, boost gauge, 1g bov and hard uicp, rewired fuel pump, stock 450 injectors, and a logger, currently running 15psi on the setup, 0 knock. I just wanted to squeeze a little more out of the t25 before I get a 14b on. From there, I plan to port the exhaust manifold and o2 housing, and finally get a new dp/exhaust and hopefully new fuel pump and injectors soon after.

 

[JayRolla]

You cant do much with stock injectors. I would leave it where its at. 15psi with no knock is not bad on stock fuel.

 

[ILLiCliPSE]

i personally wouldnt try to get any more power out of the t25...you're fine where you are right now. at 15psi, its basically maxed out and blowing hot air, although you do have no knock. wait till you get the 14b installed, then start tuning.

 

[always_broken]

There's no tuning whatsoever he can do? So he can practice with it and be prepared when it comes down to the turbo upgrade.

 

[calreef18]

Thanks for the advice guys, as always broken said, is there anything I could do? I already have the safc so if I could mess around with it a little that'd be great just to get familiar.

 

[JayRolla]

Turn up the boost to 17psi and most likely you will be blowing hot air causing all kinds of knock. A stock fuel system cant take any more than about 14-15psi. You can turn it up 2 psi, do a log and add a little fuel where you see it knock.

 

[CanadianTSi]

The stock Fuel system can handle anything the T-25 can put out.

If you really want to you could take out about 5% up top.

 

[paul s]

I have used DSMlink on my wifes car(t25) and found that on 94 octane at 16psi I was able to take out 6-7% of fuel out with out much knock(.4-.7 deg). On 91 octane you can't go as lean as you will get knock in 4th above 5000rpm. I run 14.0@98mph on stock t25(ported a lot)intake,bov, hard pipes and 2100 clutch, stock exhaust and rewired pump. By turning up the boost you will gain a lot of torque but little hp. I have 15psi at 2300rpm. At 17 psi with afr around 11.0 the injector duty is at 90%. here is the log
http://www.dsmlink.com/forums/attachment.php?attachmentid=7467

 

[Eastwood95]

There should be no "tuning" going on with the stock injectors still in. Whats the point of "maxing out" the T-25 anyways? The boost doesnt hold past 5500 rpms......

I mean turn up the boost if you want, but I wouldnt change any fuel trims.........
and you positive you have 0 knock? Or are you looking at your timing and o2 from your logs and guessing?

 

[calreef18]

Just using the timing and 02 logs, so I'm not 100% positive of 0 knock, just that its low enough that no timing is being pulled. Would you say with the 14b upgrade the pump or injectors first? I've read opinions going both ways, and I'm eventually going to get both, just wanted to see what would be best if I had to choose one first.

 

[twocanewayne]

the f/p.

 

[paul s]

why would there be no tuning the t25?. the stock fuel maps are very rich, when using good fuel (94oct) you can lean it out some and gain power. The stock afr at WOT in the upper rpm is set to around 9.5-1 wich is way too rich to make power. It is set like that to cool the intake charge. I have gained about 30hp and 50lb of torque by running 16-17 psi leaning it out a little and adding some timing around 5000rpm.

 

[Phil97GST]

wow thats nice, but it is neccessary for an afc in stock trims?? will it be a good enough gain of hp??

 

[Eastwood95]

I would say go with the fuel pump first, for one its cheaper and you can knock out the rewire at the same time. Getting the injectors first would be like working backwards, since the stock pump would have the same output.
I have heard people getting by with a rewired stock fuel pump with upgraded injectors.
You should definitely get the turbo-back exhaust before you upgrade the turbo or worry about the pump/injectors. That will free-up alot of the restricted horsepower that you're hungry for.

It isnt necessary for the SAFC on a T-25 in stock fuel trim(pump/injectors).

Paul, you're completely correct on leaning out the T-25 for more power. It seems almost pointless to me to "tune" the T-25 because its such an inefficient turbo. I also understand that ALL of us would dump the T-25 ASAP if we had the money, and sometimes we have to work with what we have(like most of us, I've been there). So since he already has the SAFC, it's possible to lean it out a little and make some extra ponies. My point was that the SAFC was intended to compensate for upgraded injectors.

 

[pnishr]

I'm gonna have to go with Paul on this. There is ALWAYS room to tune... I ran my T25 into the ground, boosting to 20+PSI, no knock... If you'll see my profile, my DSMLink est was over 210whp. Of course, I had an exhaust and all that also, but, I digress. If he's GOT something to tune it with, he may as well be tuning/learning.

 

[Ultimatedsm]

The stock pump can't take much over 16 psi (Unless you rewire it). The 450 CC fuel injectors will out flow your stock fuel pump. So your weakest link will be your fuel pump first. Get a Walbro 190LPH, they are like $120 and it will give you more safety margin.

The hot air the T-25 will be blowing can be always cured by getting some kind of FMIC or larger intercooler. You can run your T-25 with a FMIC at 18 psi no problem.

Just remember to give it nice cool downs after driving your car hard. Sure you won't get 18 psi to redline (Unless you get that special Actuator from Forced Performance that will make the T-25 hold to 17-18 psi to redline). If you don't get that actuator, you won't make anymore than 12-13 psi at redline.

People say the T-25 runs out of steam at 5500 RPM, well it has been proven by Forced Performance that its the actuator that blows open at 5500 RPM (Weak spring) and not the turbo itself. Even if your 18 psi drops to 13 psi to redline, you will get a lot of mid range torque and your car will feel a lot stronger in the mid revs. So go for it and tune your car, thats what your SAFC is for so don't let it go to waste even with a stock car.

 

[calreef18]

Hey all, just wanted to add an update on my t25 stock fp and injectors, rewired, I'm running 15psi and was able to take out roughly 6-7% across the top and have a nice timing curve.

 

[Chicken Patty]

I dont know if my car has any fuel mods or not, but here is what I see.


my mods are in my profile. The T-25 spiking 16-17 psi and it rapidly drops to 12-11 and holds about 10 at redline.

I am able to pull across the whole powerband more than 10% and at redline i'm pulling about 22%.

My a/f ratio is between 11.5-11.9 all across all the way to 7.5K.

I do have stock injectors, but i'm guessing the previous owner put a pump or something because I doubt on a 100% stock fuel system I can pull soo much fuel.

However not much, but it did do a difference, definetely up top where the t-25 dies, it helped it out alot. The car doesn't fall sooooo much on its face anymore.

I'm going to be checking for knock tonight, see how it does. Whats an acceptable count of knock??? I've heard no more than 3-5 counts. Can anybody chime in on this???