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Boost Junkie
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Discussion Starter #1
Hello,

Since I can't search, I'd figure I would ask what kind of fuel pressure people see at idle in their singled Supra. I am running 28psi at idle, which I think may be too low. This is a mild 67mm turbo, cams, fuel system, 6-speed with the usual supporting mods. Let me know guys and thanks for your help.

Steve K.
 

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Hello,

Since I can't search, I'd figure I would ask what kind of fuel pressure people see at idle in their singled Supra. I am running 28psi at idle, which I think may be too low. This is a mild 67mm turbo, cams, fuel system, 6-speed with the usual supporting mods. Let me know guys and thanks for your help.

Steve K.
43-45psi. Hope that helps. 28 is definitely too low.
 

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Boost Junkie
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Discussion Starter #4
Damn,

That is amazing. I can't believe my car ran as well as it did at high boost before with the auto. The reason I asked is that at high boost with the auto I had no issues at all with a/f ratios, steady in the 11s at 29psi. With the 6-speed I went tuning last night and could not run more then 22psi boost. The load on the engine is totally different now with the 6-speed so it make sense. I knew my injectors weren't maxed out so I figured it was a fuel pressue problem. I'll adjust the fuel pressure and try again tonight.

Thanks guys,

Steve K.
 

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Was the 29 psi with the vacuum hose still connected to the regulator? I am guessing it was, if so, that is about 38 psi.

Pull the vacuum hose to check & adjust. Or, if you can run the fuel pump w/o turning on the car, that is the easiest way. Then you dont have to disconnect the hose.

Al
 

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I would set it around 42psi with the HOSE OFF. Like has been stated easiest way is to do this with the car not running but the fuel pumps going.
 

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Boost Junkie
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Discussion Starter #7
Thanks guys,

The 28psi is at idle so yes, some fuel is pulled due to the vacuum present in the system. I am going to increase the fuel pressure to 42psi with the hose off and see what that gives me with the hose connected. Hopefully I can at least run a few more lbs of boost. Last night I couldn't get the a/fs out of the 12s at anything over 22psi. I'd add fuel on the AFC and nothing would happen so I may have been maxing out the signal. At least now the added fuel pressure should allow me to run a few more lbs of boost.

Steve
 

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Boost Junkie
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Discussion Starter #10
O.K., I raised the fuel pressure to around 42psi static and went out and did some tuning last night. I was able to make 25psi of boost with a safe a/f of low 12s into the mid 11s after boost was at its peak. I think I could turn the boost up higher since that was only on setting 55 out of 100 on my Blitz BC, but at that power level, it was too dangerous to try and tune on the street. I may hit the dyno this weekend to see how it does at 28psi. I estimate my power to be at 660-670whp at 25psi. I don't see how these guys making more power can use it as I spun the 315 BFG Drag Radials at 100mph on concrete at this power level.

Thanks for the help guys.

Steve
 

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Pays Cash, No Questions
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42psi psi static here.
Same for me - Steve - good luck with the dyno! Tell us how you do, and hopefully I can meet you at Beech Bend this year. I'm excited to have the car together and some more plans for it as well, and I can't wait to see yours.
 

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Boost Junkie
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Discussion Starter #12
Hey Bud,

I don't know if I will track the car or not this year. Just have to see. I may be down there for that Import Alliance meet in July, just have to wait and see how hot it is going to be.

Steve
 

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what dyno are you going to go to?

also, what time are you going to be out tomorrow for the meet? Trey and I are talking about meeting early to get some food. Care to join?
 

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I estimate my power to be at 660-670whp at 25psi. I don't see how these guys making more power can use it as I spun the 315 BFG Drag Radials at 100mph on concrete at this power level.

Steve
Are your drag radials old or have they been heat cycled a lot? Are you on a suspension that squats badly and gives generates a lot of negative rear camber under hard acceleration? Both sets of 295 BFGs that i've had would hook up on concrete from a roll in any gear, 1st included, with boost at a setting that would show about 750 whp on a 4th gear dynojet pull... That kind of power would spin older Pilot Sports at about 100 MPH, but the DRs hooked like crazy. All this on stock suspension. NOW, the first set of DRs got to the point that they'd spin in 3rd on pavement when they got old, but when they were new they were amazing (just like the curent set which are nearly new).
 

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Boost Junkie
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Discussion Starter #15
No, they are brand new, but it is still cold here, in the low 50s at night. Right now it is 85 degrees out and they hook wonderfully as I just did a pull here on the way to work to get some things done. I am also running 15psi in them vs. the 23psi or so that I started at trying to figure out the sweet spot. My suspension set up is JIC FLT A2 coilovers set to 2 steps before full soft, so it is squatting now more also compared to where they were set before. I am very happy with the drag radials now.

The funny thing also is that I am able to run 28psi boost now because of the hotter air vs. 50 degree weather (I could run 26.5psi or so last night in 50 degree weather). The MAF is still totally maxed so the airflow is the same, just less dense air today.

Now I just need to figure out if I want to go AEM or MAP ECU. Time to do some research.

Steve K.
 

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any good runs last night steve?
 

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Boost Junkie
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Discussion Starter #17
No, not at all. No one showed up except Mark and I and I got a ticket even though I wasn't speeding....long story. Hopefully I can get it dropped at court.

Steve K.
 

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No, they are brand new, but it is still cold here, in the low 50s at night.
The temperature is probably a big factor. Everythign I said before was assuming warm tires (just driving around to warm them to normal operating temps -- no burnouts). Also, I get the results I mentioned on about 25-26 PSI inflation pressure.

Re: your other question, I've been running 46 PSI static ever since I installed the SP fuel system in 2001.
 

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Life begins @ 30psi....
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No, they are brand new, but it is still cold here, in the low 50s at night. Right now it is 85 degrees out and they hook wonderfully as I just did a pull here on the way to work to get some things done. I am also running 15psi in them vs. the 23psi or so that I started at trying to figure out the sweet spot. My suspension set up is JIC FLT A2 coilovers set to 2 steps before full soft, so it is squatting now more also compared to where they were set before. I am very happy with the drag radials now.

The funny thing also is that I am able to run 28psi boost now because of the hotter air vs. 50 degree weather (I could run 26.5psi or so last night in 50 degree weather). The MAF is still totally maxed so the airflow is the same, just less dense air today.

Now I just need to figure out if I want to go AEM or MAP ECU. Time to do some research.

Steve K.
Steve -

I would go AEM hands down for what you have in the car. The only thing that would be a concern is having a decent tuner close to you. It will make all the difference in the world. My car is still running on email tune and drives great but it would be perfect of I had a qualified tuner closer to me.

Bob
 
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