Here is the (basic) setup

B20B untouched bottom end
B16A head/injectors w/ a B&M fpr set at 45 WOT
S2 IM
VAFC- untuned other than VTEC set at 4900
DC b16a header and too small exhaust (no cat)

Car seems to have the torque but the top end feels barely any faster than the previous b16a. I have read that my fuel pressure needs to be higher to run the B16A injectors. So what should the FPR be set at?

The spark plugs look good but the exhaust reaks of gasoline. It doesn't even smell like exhaust- just like pure gasoline; the car gets like 26-28 MPG on the highway. Am I having incomplete combustion? I am running 93 octane even though I have relatively low compression (9.5 ish I believe).

ANY suggestions on VAFC/FPR settings would be appreciated. New injectors (prelude maybe)?


Thanks guys.

 

id run like 48 or so. may sound a lil high but thats what i used to do

 

I have read upwards of 50 psi. I even saw some dyno plots that the owner stated 60 psi; what are the negative effects of running such high pressure? premature injector failure?

 

before bedtime bump

 

yes premature injector failure, stock pump will suffer also.

 

Fuel pump has been replaced. If I get say prelude injectors would I still need to run a high fuel pressure?

RC Engineering's website shows that as you increase fuel pressure, a 240 injector will flow more cc's- but I know that fuel pressure is different from fuel volume. Having a higher fuel pressure does do more than add a little fuel volume correct?

 

correct.........high volume and pressure are different........goes for the 10 is 10 arguement for turbos. you need a good pump and injectors to take advantage of this setup. Low compression of your engine doesnt help matters either.

 

I was running 50+ psi on my 270 venom injectors, and the car ran lean as hell. I went to 440s and put my pressure at 42, tuned the car and all is well!!!! At very least you'll want 310s. Set pressure for stock and tune it out with the VAFC. By running the pressure that high, you really stress the pintle on the injector. You've got to figure that those things are probably at 99% duty.

 

I know that running lean can increase power to some extent, but at what point does running lean become bad? Is it good right up until detonation occurs?

Is the gasoline smell from the exhaust indicative of anything?

 

In regards to your lack of top end punch....

Your engine is overcammed. Meaning that your cam profile is too aggressive for your compression. Also that wimpy DC header is killing you. 2L vtec engines need a 2.5" collector or bigger.

 

So are you saying that the cams are bleeding off the compression before combustion takes place? Would advancing the intake cam and retarding the exhaust cam help out? ( I am familiar with the valve clearances associated with my motor)

 

Its those injectors , I have a Ls/vtec and tried running the stock 240's and it would do the same thing . Your injectors are maxed are going to fail and if they are old they probably will not even flow 240 cc's anymore . I put 310's in mine and its pulls harder across the whole powerband . Your cams are fine and I doubt you have detonation problems with that compression . Oh and I also built a B20 and it was the same story has to have biggers injectors .
Forgot to mention that a Vafc cannot add fuel at WOT , only take away . Just in case you didnt already know that .

 

B&M is poop.....and I think the pressure is fine. I would suggest adjusting the VAFC injector percentage higher on the top end, and leaner on the bottom, as well as bumping VTEC up to at least 5K. You probably need a bigger pump, or add an inline one.

 

The fuel pump has been replaced as previously stated- stock WRX unit for whatever thats worth.
Sounds like I definately need new injectors along with a bump in the fuel pressure.
Is there any way (other than dyno time) to determine when you have the proper fuel pressure?

 

go to a freaking dyno and tune the car for goodness sake!

that is the only way to work it out, much better than the second guessing that is happingin in this thread!

BTW i am runing my 9.5:1 CR B20VTEC with R cams and R extractors at 45psi with VAFC doing very little in terms of fuel...

teh A/F's sit at around 13:1, this seems to be fine...

goto a dyno to tune your engine

 

I ran a B20VTEC with 360cc injectors off a DSM (so Im told) for a while on a stock PW0 ECU with stock B20B bottom and B16a head.

It ran great. Leaned off the fueling a little on the ECU with a chip and it ran better.

Dont use an FPR when the engine is going to run pretty damn fine on a stock tune with bigger injectors. Do it "properly".
It could just have easily been altered with a V-AFC rather than a chip.