Fuel Question

[SexyDSM95]

Just a quick question:
I installed a Walbro 255lph pump and I don't have injectors or a larger turbo. If and when I slap on my 3" DP with Evo O2 housing is it safe for me to increase my psi from 15 to 17? Or should I stay safe and maybe just up it to 16? I don't have S-AFC mind you and probably won't get it becaus I am stubborn and want DSMlink instead Oh, and what problems may arise from having a 255lph pump and no injectors/turbo just bad gas mileage?

 

[CanadianTSi]

The thing that you need the most right now is an Adjustable Fuel Pressure Regulator.

The bigger pump is overwhelming your stock piece and causing you to run rich at Idle.

Most people will tell you that it is pointless to run more then 15psi on the T-25 but we did dyno my friends T-25 car last night and it made more power at 19psi then it did at 15

 

[SexyDSM95]

Actually I am not running rich at all.....

 

[CanadianTSi]

Actually I am not running rich at all.....

Does your wideband tell you that you're running 14.7/1 at idle?

 

[BigBoosh3712]

You are more than likely over running your FPR. Your fuel curve won't be linear, but you'll be alright. Yea, go ahead and turn up the boost. I ran 17psi on my T25 on pump gas on a stock pump. I think it's safe to set yours as 17 as well.

 

[SexyDSM95]

You are more than likely over running your FPR. Your fuel curve won't be linear, but you'll be alright. Yea, go ahead and turn up the boost. I ran 17psi on my T25 on pump gas on a stock pump. I think it's safe to set yours as 17 as well.

Well when I ran at the track and set it to 17 w/o my DP and fuel pump I spiked to around 22. So I was like ummm we will turn that back down to 15. I was thinking maybe boost spike/creep due to not having a full 3" DP and 02 housing. But yea like I stated before I am not running rich what so ever maybe my gas mileage sucks a tad but that's about it. As for wideband I have no logging tool or SAFC so I have no idea.

 

[steve]

Actually I am not running rich at all.....

As for wideband I have no logging tool or SAFC

So in other words you have no idea if your running rich on not.

Steve

 

[SexyDSM95]

haha pretty much I most likely am. Well looks like it's time for a FPR!

 

[steve]

You can live being rich at low rpms where FPR overrun is most likely. Perhaps a datalogger might be a better investment first unless your saving your money for a DSMlink.

How long before you can afford it?

Steve

 

[Bohrn]

Sandra, get an adjustable pressure regulator soon.

I let it go but you know what?

I had so much fuel for so long that I have a ton of carbon build up in my combustion chambers. And not just on my piston tops either, but on the valves, the roof etc. It will be either take off the head and get it done, or run water injection (and an adj fpr) for a while and steam clean my head.

See, the extra carbon causes knock by raising compression and also by making nice little glowing embers that act like spark plugs, but at the wrong time.

and knock sucks ass.

PS, water injection does not suck ass

 

[SexyDSM95]

Sandra, get an adjustable pressure regulator soon.

I let it go but you know what?

I had so much fuel for so long that I have a ton of carbon build up in my combustion chambers. And not just on my piston tops either, but on the valves, the roof etc. It will be either take off the head and get it done, or run water injection (and an adj fpr) for a while and steam clean my head.

See, the extra carbon causes knock by raising compression and also by making nice little glowing embers that act like spark plugs, but at the wrong time.

and knock sucks ass.

PS, water injection does not suck ass

Oh jeebus...how long did you run without APR? I honestly can't afford it for maybe another 2 weeks...

 

[SexyDSM95]

Oh and BTW how much boost were you running?

 

[Bohrn]

oh, 2 weeks will do you no harm I don't think. How long have you been running the big pump with the stock regulator already?

As for boost, well, it doesn't matter really, but between 15 and 18 psi.

 

[SexyDSM95]

oh, 2 weeks will do you no harm I don't think. How long have you been running the big pump with the stock regulator already?

As for boost, well, it doesn't matter really, but between 15 and 18 psi.

I slapped it on last Sunday so almost a week. I talked to a couple of my DSM buddies and they said the carbon build up is after LONG term use not a couple months. I was also told that maybe SAFC would be a better bet and AFPR would be pointless for me to have at this point since I don't want to go above 20psi. If I get SAFC I would most likely get 550 or 660 injectors anyway so I would be in the clear. Thanks though guys for the help!

 

[Bohrn]

and adj fuel press reg will NOT be pointless.

http://www.taboospeedshop.com/FPR.htm