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supraman
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632 Posts
Discussion Starter #1
Does anyone know what max boost you are getting with the 1st turbo? Also how much boost do you get on 1st and 2nd gear?:)
 
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Randy,
you joined this fourm about the same time I did. Looks like we are in a simular boat with our supras (wanting to get the most out of them and still learning) Between your questions and mkiv.com I have learned a great deal. Keep them comming.

Good luck with your Supra and your boost. Still getting there myself.

Erik
 

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95Turbo
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930 Posts
I'm running 18-19lbs. on both stock turbos, I have the TTC mod (true twin conversion), there was a little more lag, but the turbos hit much harder. I have the VPC, Boost Contr., FMIC,upgraded computer, and BPU++

I think stock boost may be 11 and 13, but i'm not sure... soemone want to back me up on this????
 

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supraman
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632 Posts
Discussion Starter #4
Stock boost is around 11.5psi.
Come on guys! Does'nt anyone have any idea what kind of boost your first turbo builds? We know the second turbo really kicks in with 18/19psi!:rolleyes:
 
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randy said:
Does anyone know what max boost you are getting with the 1st turbo? Also how much boost do you get on 1st and 2nd gear?:)
Primary turbo consistently hits 11psi regardless of gear (But it will creep higher in high gears on a long full throttle pull). As far as max boost in 1st and 2nd gear, which is what I am assuming you are asking, about 15psi in 1st, and 17-18 (full boost) in 2nd.

Mike T
 

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STREET STOMPING JEDI
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1,039 Posts
Its ok,

I know what your asking....

As far as I have been told by Toyota techs. The stocks Individually can spike as high as 15 lbs a piece. But only for a second or less. The first turbo is the same as the second turbo... If you notice boost spikes between when the first turbo falls off adn teh second kicks in dont be alarmed, but know that you cannot maintain the type of boost it may seem is available.

I have heard of stock twins spiking to 25lbs. for a brief moment but that I am told is there limit and you are asking for trouble pushing to that unless you plan to go single anyway. (not to mention I hear it is not easy to get them to boos that high)

Good luck and if you cant find exacting info on what your asking, "how much boost is the first turbo capable of" then ask your local Toyota master tech. he may an dmay not be able to help, and you can always try the big shops as well. PHR, RPS, SP, etc....

Ben..
 

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supraman
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632 Posts
Discussion Starter #7
Thanks for your response Mike/Ben! The reason I am asking is cause I will be doing the HPF boost mod and this will make my first turbo boost as high as18/19 psi, just wondering how much the first turbo on BPU would boost compared to first turbo HPF mod.
Aprox boost levels with HPF mod according to a friend.
1st gear-17/18psi
2nd gear19/20psi.
3rd gear 21/22psi.
5th gear 25psi.
6th gear 27psi.
You can see I really have to control the boost with the accelerator. and a boost guage with peak hold warning buzzer.
 
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randy said:
Thanks for your response Mike/Ben! The reason I am asking is cause I will be doing the HPF boost mod and this will make my first turbo boost as high as18/19 psi, just wondering how much the first turbo on BPU would boost compared to first turbo HPF mod.
Aprox boost levels with HPF mod according to a friend.
1st gear-17/18psi
2nd gear19/20psi.
3rd gear 21/22psi.
5th gear 25psi.
6th gear 27psi.
You can see I really have to control the boost with the accelerator. and a boost guage with peak hold warning buzzer.
I assume you are running the J-spec ceramic turbo's. I would expect your turbo(s) to blow apart at any moment with that level of boost.
 

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supraman
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632 Posts
Discussion Starter #9
That is the reason I'm hesitating doing the HPF mod! Currently my car feels real fast hitting boost cut on 3 gear at about 5000 RPM. Infact it accelerates so hard the wheels spins even when I am rolling on 2nd gear when it hit the metel. I'm told that boost cut on jap spec is at 16psi. Boy I hit boost cut real hard. Quite shocked the power increase after my custom 2 1/2 front pipe and 3 inch midpipe with no cat. Will check my boost level when I install the 60mm boost gauge and BCC.
 
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If your looking for people with High boost on the 1st turbo search for "PT" or (Pressure Tank) HKS EZ Documentation. People with there Boost Controller hooked up to the pressure tank like HKS recommends will get you big boost on the #1 like 17-18PSI.
 
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randy said:
That is the reason I'm hesitating doing the HPF mod! Currently my car feels real fast hitting boost cut on 3 gear at about 5000 RPM. Infact it accelerates so hard the wheels spins even when I am rolling on 2nd gear when it hit the metel. I'm told that boost cut on jap spec is at 16psi. Boy I hit boost cut real hard. Quite shocked the power increase after my custom 2 1/2 front pipe and 3 inch midpipe with no cat. Will check my boost level when I install the 60mm boost gauge and BCC.
The general consensus with J-spec car here in the UK is restrict boost to 18psi, I know of people that have lost turbo's within hours of turning the boost up too 18psi and one guy at stock boost levels..

Those boost levels are crazy even on steel turbo's.

If I remeber correctly isn't this the mod someone developed and basically stated that it would blow your turbo's.....madness
 

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supraman
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632 Posts
Discussion Starter #12
I have been advised by quite a few mkiv nz members who own supra jap spec not to go over 19psi! What do you think my best options are? cause I dont yet have a boost controller and wanted to do the HPF mod. But guess its not worth risking my turbo? Do you think I should buy a boost controller and be done? Is 18/19 psi good enough power?
 
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randy said:
I have been advised by quite a few mkiv nz members who own supra jap spec not to go over 19psi! What do you think my best options are? cause I dont yet have a boost controller and wanted to do the HPF mod. But guess its not worth risking my turbo? Do you think I should buy a boost controller and be done? Is 18/19 psi good enough power?
I would buy a boost controller, set it too 19psi and leave the HPF mod well alone.

18/19 psi is the right amount of power on those turbo's if you want more do the job properly and reliably, consider aftermarket turbo's with the appropriate mods e.g. fuel system, IC etc.

No offence to anyone on this forum but the UK and Aus/NZ Supra boards are much better qualified on matters surrounding ceramic blade turbo's and the J-spec car in general.


regards...................
 
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