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Fuel pressure and timing

609 Views 12 Replies 4 Participants Last post by  nasty92LX, 
N
Ok The track just opened about two weeks ago. Here is the problem. This on junk street tires and will micky et streets slow me down. They are 28inched high and the street tires are 26 inches high.

1st run- 65lbs fuel,launch rpms 900 [email protected] 60ft 1.98
2nd run- 40lbs fuel,launch rpms 1500 [email protected] 60ft 2.17

Neither of them spun
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ryans88gt
how did you get a lower 60 foot time by launching at a higher rpm? And why were you running 65 PSI fuel pressure??

you can get ET streets in 26" and they will never slow you down over street tires. You will be able to launch at 4500 rpms instead of bogging it out of the hole.
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N
My car is an auto and i already have the tires. My buddy gave a the reg. and i told me it was at 40 and i just checked it after the run. With the 40lbs of fuel the car fell on its face.
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ryans88gt
Are you sure your fuel pressure gauge is any good? Sounds like 2 pieces of evidence that the gauge might be bad. First you get a different reading than your friend, then your car falls on it face with what should be adequate fuel pressure.
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N
that i have checked with four guages. They are all the same. I have 24lb injecotors. With a big cam do you need more fuel.
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e3sean
nasty92LX said:
that i have checked with four guages. They are all the same. I have 24lb injecotors. With a big cam do you need more fuel.
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is it 40 with the vaccume on or off? or is it a stock FPR
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N
it is not a stock and the vac line was off when it was set
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nolife
At your power level (250-280 fw maybe?), if you are falling flat at 40PSI with 24# injectors, you have other problems and increasing the fuel pressure to 65 is just a temporary fix.
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N
At your power level (250-280 fw maybe?), if you are falling flat at 40PSI with 24# injectors, you have other problems and increasing the fuel pressure to 65 is just a work around.
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Well i think my car make a good amout more than 250 to 280 at the fw. And what other problems do u think i might have
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nolife
My estimate is rough based on your 1/4 times. No idea but 65 is really high to keep it from going lean.
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N
I was thinking i might need to go to 30lb injectors and the reason the times are not that great i have to leave on an idle or the will blow the tires apart. I have the car at 50lbs right now and it seems to be running good.
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ryans88gt
What else is on the car? 24 lb injectors should be good for about 350 hp at 65 PSI. Based on your timeslips you are nowhere close to that level. I would guess that if anything you have too much fuel or you have some other problem. Only way to know for sure is to take it to a dyno or buy a wide band O2.
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N
could it be my mass air that is screwing everything up. i have one of those pro-m mass air that u can ajust to what size injectors u have.
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