Turbo related question

Post by **DjLiquid** » Sun Sep 17, 2006 7:45 am

My T25 is blown and I want to swap in my T28, 550cc injectors, and my walbro fuel pump. Now here's a question that I have. The ecu I have isnt tuned for the bigger injectors and fuel pump. I have to be able to drive this car to the tune shop. Technically, I should be able to drive it, but just not boost, is this correct? If I boost, I will lean out the engine and that would be badddd =(

Post by **kapower06** » Sun Sep 17, 2006 8:09 am

No! the car most likely wont even Idle with that big of an injector. I deffinatly wont be able to accelerate at all either. On top of being 180cc bigger then stock, you also have the walbro pump. I doubt it will even start up. You have to get some kind of fuel controller or a base map ecu set for 550cc's, then a piggy back to fine tune with.

Post by **c-rad** » Sun Sep 17, 2006 8:10 am

The fuel pump has nothing to do with the ECU. And with 550cc injectors, your car isn't going to go anywhere. It won't lean out, it will flood and die. Think about it... the injectors are 33% larger than stock. So everytime the ECU signals the injectors to open for a certain duration (milliseconds), 33% more fuel is being dumped. I say just leave the stock injectors in there til you get the ecu tuned. Only took me about 30 mins to swap out my injectors.

EDIT: Damn it... beat me to it.

Post by **DjLiquid** » Sun Sep 17, 2006 12:08 pm

ok, thanks.. ill swap the fuel pump and bring the injectors so I can swap em over during the test and tune =)

Post by **float_6969** » Sun Sep 17, 2006 4:35 pm

From experience, the stock ECU will not run the motor w/the 550's. As Chris said, the walbro doesn't have much efffect on it, although I would reccommend some sort of aftermarket FPR if you're gonna run the Walbo as it definatly overruns the stock FPR.

Post by **DjLiquid** » Sun Sep 17, 2006 6:12 pm

float_6969 wrote:From experience, the stock ECU will not run the motor w/the 550's. As Chris said, the walbro doesn't have much efffect on it, although I would reccommend some sort of aftermarket FPR if you're gonna run the Walbo as it definatly overruns the stock FPR.

im already on top of that. im picking up a nismo fpr in a week or so along with a wideband sensor and some stronger axles =)

Post by **dattodude** » Sun Sep 17, 2006 11:20 pm

Yeah, if you had an adjustable FPR, you could wind the fuel pressure down 33% and see if it will idle, then finetune fuel pressure up and down until you get a clean idle. Not recommended for any revving or decent load...but in theory it works. I know because I put a sard FPR on mine, and found the fuel pressure needed to be dropped lower than standard to stop it from flooding at idle. This was just the difference from the stock FPR to the sard unit. The autronic had been tuned before I put the Sard FPR on.

So it's all pretty interesting stuff :-) But it would be safer if you put the injectors in at the place where the ECU will be tuned. Unless you are happy to tow the car the shop.

Post by **DjLiquid** » Mon Sep 18, 2006 6:27 am

I figured I would ask since it was brought up. How much PSI is the stock FPR set for? 37.5 Ive been hearing but that doesnt seem right. Can anyone confirm this?

Post by **biosehnsucht** » Mon Sep 18, 2006 11:29 pm

this was recently covered..

zerothread?id=196613

second post! float gets it right.