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Fuel pressure question
#527124
11/15/09 09:16 PM
11/15/09 09:16 PM
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Joined: Jan 2003
Posts: 1,633
Jacksonville, NC
RonP
OP
top fuel
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OP
top fuel
Joined: Jan 2003
Posts: 1,633
Jacksonville, NC
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Ok, I ran a local 1/8 mile footbrake race yesterday and managed to finally take some in car footage. These are nothing special, but what do you think about the fuel pressure. I have it set at 8psi. I have never paid any attention to it going down track. It seems to be dropping down to 6psi down track. It even dips below that in one video and it doesn't look steady at all going down track The car ran/runs awesome. Made it down to 6 cars out of 133. had a new best MPH of 114 later in the night so I don't think performance is hurting, but is it worth looking into? http://www.youtube.com/watch?v=4hqD4OzpCpUhttp://www.youtube.com/watch?v=NNzg7EHh4E4
Last edited by RonP; 11/15/09 09:31 PM.
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Re: Fuel pressure question
[Re: RonP]
#527125
11/15/09 09:24 PM
11/15/09 09:24 PM
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Joined: Oct 2004
Posts: 5,618
long island NY
Ari440
master
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master
Joined: Oct 2004
Posts: 5,618
long island NY
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what fuel pump do you have
also what size d/r,s and air do you have
first vid fuel pressure went down to 5-6 psi
1.39 9.85 - 137 mph
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Re: Fuel pressure question
[Re: Quicktree]
#527128
11/15/09 09:29 PM
11/15/09 09:29 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
shouldn't be a problem. pretty normal for it to drop a little.
 go up to 8.5 psi. according to john at product engineering, there arent any negative effects dropping to 5-6 psi.
i run 5.5 psi now on my big motor.
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Re: Fuel pressure question
[Re: Quicktree]
#527129
11/15/09 09:30 PM
11/15/09 09:30 PM
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Joined: Jan 2003
Posts: 1,633
Jacksonville, NC
RonP
OP
top fuel
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OP
top fuel
Joined: Jan 2003
Posts: 1,633
Jacksonville, NC
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Quote:
shouldn't be a problem. pretty normal for it to drop a little.
I wasn't sure with all the fuel pump talk on here. I have an aero a2000 in the trailer. Just never plumbed it in. I don't want to go chasing something that doesn't matter.
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Re: Fuel pressure question
[Re: RonP]
#527130
11/15/09 09:44 PM
11/15/09 09:44 PM
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Joined: Oct 2004
Posts: 5,618
long island NY
Ari440
master
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master
Joined: Oct 2004
Posts: 5,618
long island NY
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air presure in the drag radails (sp)
1.39 9.85 - 137 mph
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Re: Fuel pressure question
[Re: Bob_Coomer]
#527133
11/15/09 09:55 PM
11/15/09 09:55 PM
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Joined: Jan 2003
Posts: 1,633
Jacksonville, NC
RonP
OP
top fuel
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OP
top fuel
Joined: Jan 2003
Posts: 1,633
Jacksonville, NC
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Quote:
As said it should hurt a thing, but that would have me wondering what it would look like at the end of a 1/4 mile blast though. 
Hope to find out soon again. I haven't changed anything since the last time I ran it in the 1/4 and it was running 138mph range all the time.
thanks guys. I guess it being so unsteady wasn't what I expected.
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Re: Fuel pressure question
[Re: RonP]
#527134
11/15/09 11:28 PM
11/15/09 11:28 PM
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Joined: Aug 2003
Posts: 43,157
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,157
Bend,OR USA
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The true test is if you can jet the carb. fat enough to slow the car down in the 1/4 MPH (I have been able to jet them fat enough in the 1/8 to slow them down but that didn't affect the 1/4 MPH  )you do have enough fuel volume, if you can't jet it up enough you don't  I think Monte had suggested to try lowering the pressure to 5.5 to 6.5 to help eliminate aireatting(SP) the fuel supply, air will compress and make fuel pressure readings erroneous. try both 
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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air?