Losing fuel pressure?
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Losing fuel pressure?
Question... On a 75 wet... Does there tend to be problems with maintaining fuel pressure throughout the run with the stock fuel pump?
I know the base is 62psi for the pressure but what is the fuel pressure at WOT? I am looking for the right jets to buy but when I use the jetting calculator online and base it on 62psi those jets seem to make me run way lean.. Makes me think I'm losing fuel pressure?
Calculator seems more accurate when basing it on 30 psi which is a huge difference.. More accurate in the sense that the jets and shot size match with what people here are running on their cobalts..
I will be connecting a friends wideband today and running a shot but I'm not sure what jets to test it out with..
Should I be basing my jets on this 30psi of fuel pressure? Or get a new pump.... Help if you have any ideas. Thanks.
P.S. 75 shot.. 91 octane.. Would it work? (That's what I've been trying)
Bump..
What is the fuel pressure at when WOT on a 75 shot? ANYONE?
I know the base is 62psi for the pressure but what is the fuel pressure at WOT? I am looking for the right jets to buy but when I use the jetting calculator online and base it on 62psi those jets seem to make me run way lean.. Makes me think I'm losing fuel pressure?
Calculator seems more accurate when basing it on 30 psi which is a huge difference.. More accurate in the sense that the jets and shot size match with what people here are running on their cobalts..
I will be connecting a friends wideband today and running a shot but I'm not sure what jets to test it out with..
Should I be basing my jets on this 30psi of fuel pressure? Or get a new pump.... Help if you have any ideas. Thanks.
P.S. 75 shot.. 91 octane.. Would it work? (That's what I've been trying)
Bump..
What is the fuel pressure at when WOT on a 75 shot? ANYONE?
Last edited by ChriSS/SC; 09-19-2009 at 06:18 PM. Reason: Automerged Doublepost
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I'm just really wondering what the pressure is at WOT on spray.. I cant figure out which jet to get. People here use what seems to be jets based on 30-35psi...
Idle psi is at 60-62
Idle psi is at 60-62
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that weird do you have a fuel pressure guage installed...you should check to see if maybe your pump is going bad...cuz i keep a constant 60 psi at all times...its not until i hit around about 5.5krpm that it starts dropping a lil to about 58psi...you should check that your pressure is good
maybe your fuel filter is clogged...how many miles you got on your car? have you changed the fuel filter at all?
maybe your fuel filter is clogged...how many miles you got on your car? have you changed the fuel filter at all?
Last edited by mrsilent13; 09-19-2009 at 06:37 PM. Reason: Automerged Doublepost
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well i bought one from autozone for 30 bucks...but now i have an electronic one installed in the cabin...with the sending unit installed on fuel rail that i got from glow shift for 50 bucks from ebay
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^ Good question.
I wonder if my fuel filter is clogged.. And I wonder if getting a new fuel pump would maintain my flow at 60psi @ WOT... Cuz if it maintains a constant fuel pressure.. And I know what it is.. I think I can get it to work right when tuning with the wideband and what not..
I wonder if my fuel filter is clogged.. And I wonder if getting a new fuel pump would maintain my flow at 60psi @ WOT... Cuz if it maintains a constant fuel pressure.. And I know what it is.. I think I can get it to work right when tuning with the wideband and what not..
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JW, is your kit used or new?
Last edited by damien; 09-19-2009 at 10:42 PM. Reason: Automerged Doublepost
#13
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My kit is used..
I wonder what my FP is aw WOT on a 75.. **** haha.
It would make sense to me if the FP was not consistent and if it was losing pressure.. Cuz the jets people use are based on a much lower FP based on the jetting calculators.. damien what jets do you use and how did you choose them? What shot are you running and what's your FP @ WOT?
I wonder what my FP is aw WOT on a 75.. **** haha.
It would make sense to me if the FP was not consistent and if it was losing pressure.. Cuz the jets people use are based on a much lower FP based on the jetting calculators.. damien what jets do you use and how did you choose them? What shot are you running and what's your FP @ WOT?
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Hm.. Yeah see a 42/26 is right when setting the fuel pressure to 30 in the calculator..
And every other combo people run matches with 30psi of fuel pressure.. So I should just base my jets on 30psi? That's what I don't get.. Why is it like that? I thought we had a consistent 60ish...
And every other combo people run matches with 30psi of fuel pressure.. So I should just base my jets on 30psi? That's what I don't get.. Why is it like that? I thought we had a consistent 60ish...
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^ Good to know.. You wouldn't go any higher on the AFRs right? What shot is that? Like 80?
And also.. What's your setup (All your mods?) I'm curious about what you did for your tune man.. I need some help with mine if possible.
Also, what fuel pressure do you base your jets off of?
And also.. What's your setup (All your mods?) I'm curious about what you did for your tune man.. I need some help with mine if possible.
Also, what fuel pressure do you base your jets off of?
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Fuel Filters should be changed every 30k is what I have been told, I have stuck with this, Im almost to my 4th fuel filter.
DO NOT BUY THEM FROM GM, go to Autozone, I paid $64 for my 1st one from GM, then i went to autozone the 2nd time I changed it and they had one for $14
l8r,
PD
DO NOT BUY THEM FROM GM, go to Autozone, I paid $64 for my 1st one from GM, then i went to autozone the 2nd time I changed it and they had one for $14
l8r,
PD
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^ Good to know.. You wouldn't go any higher on the AFRs right? What shot is that? Like 80?
And also.. What's your setup (All your mods?) I'm curious about what you did for your tune man.. I need some help with mine if possible.
Also, what fuel pressure do you base your jets off of?
And also.. What's your setup (All your mods?) I'm curious about what you did for your tune man.. I need some help with mine if possible.
Also, what fuel pressure do you base your jets off of?
http://www.harrisspeedworks.com/prod...cat=136&page=1
that is the kit i am running and it supose to be for an LS1 but works fine for my balt.
My mods are 2.9 pulley, 42lb injectors, Gmpp header, ZZP cattless DP, Gmpp exhaust, ZZP S3 heat exchanger, and a custom ZZP nitrous tune.
As far as jetting goes i just used what the manufacturer told me to use after i told them what fuel pressure i was at (62psi) and they recomended a 44/28 set up for a 75 shot and it has been working great. AFR's have not gone past 11.4 and usualy hang around 11.2 but as long as i stay under 11.5 i will be fine.
IMO i would get a different tune. I ran this same set up with the stage 2 tune and the timing retarded and it was prety good, but with the ZZP tune it makes a world of a difference with the same shot. My 50 shot on my zzp tune feels like a 75 on stage 2 tune.
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Wait.. You just ordered a custom ZZP tune? And told them your mods? How much did that cost you?
Our mods are almost identical.. But my nitrous kit is mix and match with different brands.. Mainly a dynotune nitrous kit though...
Our mods are almost identical.. But my nitrous kit is mix and match with different brands.. Mainly a dynotune nitrous kit though...
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But yea i love the tune and have not had one problem. Here's the link if you're intrested
http://www.zzperformance.com/cobalt_...=755&catid=144
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