vac and boost line for return line

some people say the intake manifold but for some reason i don't think that's right. It needs to be a boost only source and the manifold sees vacuum all the time. I think you would have to tee off the boost only source on the turbo itself

Uncommon says the red line in his "How To". just search for his thread in this section and you'll find your answer.

Grasshopper32 said:

Uncommon says the red line in his "How To". just search for his thread in this section and you'll find your answer.

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Why would he do that? That would be too easy mang:rofl:

It all depends on if you have it seeing vac. and boost or just boost. Your setup determinds this. My car is running the reg. on vac/boost and the drivabiltity is second to none.

i got it figured out i just t into the line on the tb spacer since its supposed to see vac and boost i thought this would work the best

d coop said:

i got it figured out i just t into the line on the tb spacer since its supposed to see vac and boost i thought this would work the best

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vac & boost will work best? .... me thinks not

you want a boost only source, trust me on this one .... srsly

just hook it up to the red line off the coldside pipe & call it a day


EDIT: if you really really really want to use the TB/IM for a source then youre going to need to get a checkvalve so that the FPR doesn't see vac or it'll pull fuel & lower the fuel pressure .... like i said above, just use the nipple off the coldside pipe & be done with it

I have mine going to where the bluw line was from the factory. Should I just put it to the upp instead?

[email protected] said:

I have mine going to where the bluw line was from the factory. Should I just put it to the upp instead?

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blue line .... hmmm, i'll have to look at the stock vac diagram ... honestly, i haven't had any vac lines in 2 and a half years now and i can't remember which lines go to what

youre best bet is to just use the nipple on the coldside pipe (stock red line) .... it only sees boost and that's exactly what you want

Like uncommon says....boost source only.

uncommon said:

[email protected] said:

I have mine going to where the bluw line was from the factory. Should I just put it to the upp instead?

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blue line .... hmmm, i'll have to look at the stock vac diagram ... honestly, i haven't had any vac lines in 2 and a half years now and i can't remember which lines go to what

youre best bet is to just use the nipple on the coldside pipe (stock red line) .... it only sees boost and that's exactly what you want

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Thanks man! I'm going to run it to the red line on the upp, and just cap off the blue line now.

how is the nipple on the cold side pipe different from the tb spacer and in the video that i got with the kit he says you want a vac and boost source i am not being a smart ass i just dont know what to do

d coop said:

how is the nipple on the cold side pipe different from the tb spacer and in the video that i got with the kit he says you want a vac and boost source i am not being a smart ass i just dont know what to do

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ok, think of it this way ....

w/o the boost source line hooked up (static pressure) you have the fuel set at sasy 50psi .... if you hook that line up to a boost only source, the lowest pressure you'll see is 50psi and then it will rise at a rate of 1:1... meaning if youre boosting 20psi, you'll have another 20psi of fuel at WOT - so 70psi at WOT


now same static pressure (50psi) but this time you hook it up to a vac & boost source .... the second you hook that boost reference source line up (to the TB/IM nipple) the fuel pressure will drop from 50psi down to whatever vac youre in on your boost gauge (my guess would be like 35 or 40 psi of fuel pressure at idle, not sure though w/o actually doing it)

ok i see why now. i will change it but i am using the nipple on charge pipe for my w/i what else could i run the fpr to

d coop said:

ok i see why now. i will change it but i am using the nipple on charge pipe for my w/i what else could i run the fpr to

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one of the two nipples on the turbo ... either of them will do

I have tried manifold vacuum, ported vacuum (before throttle plate) and static. I actually got a better yune with static pressure at 58psi. There are quite a few guys around me that run returnlines and static pressure rather then rising rate, specially on a staged PCM.

just t it in the line from the turbo to the soleniod

ImportLabSRT4 said:

I have tried manifold vacuum, ported vacuum (before throttle plate) and static. I actually got a better yune with static pressure at 58psi. There are quite a few guys around me that run returnlines and static pressure rather then rising rate, specially on a staged PCM.

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im just curious, why have a return line if your gonna have the fp at 58 psi? that's pretty much the stock fuel pressure (i think it's 58.5 +/- to be exact)

d coop said:

just t it in the line from the turbo to the soleniod

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do you have a stage 1 or stage 0? if you have a stage 0 just rip out all of the stock vac lines and then you can just use one of the nipples off the turbo


to be honest with you, im not sure which line you should use .... let me look at a vac diagram and see which one makes sense

Upgraded pump and filled regulator, so the AFPR still needs to be set. Im on a stage 2 PCM with PTP FTM and the car loves static tunes. I had a local guy help me tune because he has a similar setup on stock turbo and ran a 12.2 at the track a few weeks back. The PCM still adds fuel at high RPM's so why add more fuel with boost too? The car goes rich as hell at the top like it should and I have to pull a lot of fuel to get it down to 12.2 - 12.3:1