Qustion about my T-25 turbo is not catching and slow off the draw....

[zsimons]

I bought the car with a t-25 turbo set-up with stock injectors, and a SFMU, what is the biggest size injector I can run with what ratio disk, without using a SAFC. i think this might be why the turbo isn't catching and is real slow off the draw. if you have other suggestions let me know please thanks.

 

[ItsStockOfficer]

Your not an adavanced tuner.

The technical answer is : You cannot get bigger injectors without an safc or some form of fuel control at all. Bigger injectors just don't flow more on top end. They flow more at all times. so if you put in bigger injectors, you'll be rich at idle.

The honest answer is : I ran 510's in a car made for 450's without a problem, but 550's ran too rich. So 10-12% richer is prolly fine. But 12% is not what you need. You need 50% larger, maybe more.

 

[Larry L]

With a T25 you should only need an safc to get the maximum hp out of your stock turbo. and thats even optional...On a 2G with a stock T25 you can run a boost controller @15 psi and get tons of power. Porting it is also hella good (NOT INJECTORS YET). Plus look into the free mods they do make a difference.

I have a 2g with a ported 14b and all I use is a 255 lpm pump. And as long as I keep my boost below 16psi I dont need an s-afc or injectors the ECU and stock injectors can still manage the needs for my set up. And I dissagree: Bigger injectors will not run richer all the time...The ECU will give a signal as to how much fuel the pump and injectors to flow...The pump and injectors have the ability to run at their rated flow..(i.e. 255lpm, and 660 inj.) But if the ECU is giving a signal the injectors aren't going to run max lpm all the time...The ECU is still in control. As to your problem it could be a number of things: How high is your boost set? What is your exaust set up? And how many miles are on your car?
Everything makes a difference.

 

[nine5raptor]

Originally posted by Larry L
With a T25 you should only need an safc to get the maximum hp out of your stock turbo. and thats even optional...On a 2G with a stock T25 you can run a boost controller @15 psi and get tons of power. Porting it is also hella good (NOT INJECTORS YET). Plus look into the free mods they do make a difference.

I have a 2g with a ported 14b and all I use is a 255 lpm pump. And as long as I keep my boost below 16psi I dont need an s-afc or injectors the ECU and stock injectors can still manage the needs for my set up. And I dissagree: Bigger injectors will not run richer all the time...The ECU will give a signal as to how much fuel the pump and injectors to flow...The pump and injectors have the ability to run at their rated flow..(i.e. 255lpm, and 660 inj.) But if the ECU is giving a signal the injectors aren't going to run max lpm all the time...The ECU is still in control. As to your problem it could be a number of things: How high is your boost set? What is your exaust set up? And how many miles are on your car?
Everything makes a difference.

So much wrong here...


First off, the t25 was not stock on his...it was a non turbo.

He needs much larger injectors, at least some 450's or more and an afc to control them.

Boost at 15 psi would = BOOM! on his.

You have a 255 lph pump, not a 255 lpm. Big difference.
How do you know you can run 16 psi safely? Do you have a logger, or anything besides that boost gauge?

You are wrong on the the injectors. The rating given is the volume they flow when open and static. The ecu outputs a voltage for a certain length of time called a pulsewidth. It doesn't know if you have 450's or 720's, it will send out the p.w. that is programmed in which is calculated for 450's, thus you will run rich all the time with larger injectors and no fuel controller.


Also, on your setup, Larry L, that 3" dp to the 2.5" highflow cat is probably worse for airflow than having your stock downpipe on there. You are introducing a LOT of turbulence by allowing the air to slow down in the larger pipe and then running it into 90deg. bends at the outside. You should pick up some power by going with either: stock downpipe and the rest the same; 2.5" dp and the rest the same; or a 3" cat/test pipe and the rest the same.

Another thing, that 1g throttle body isn't doing you any good without a larger inlet on the intake mani. Again, you will probably gain by going back to the smaller 2g t.b. that allows the smoother path for the air.