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Supralicious
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Discussion Starter #1
I'm wondering, who here has the highest horsepower with a T78 on stock fuel? What are your mods? Your A/F ratio?

The reason is that I'll end up w/a T78 with no fuel for now. I wanted to see what kinds of whp I'd have on 13-14psi.
 

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not sure, but just plan for around 500rwhp on stock fuel. Dont try and push it further than that. Also, keep it at around 18psi max for high boost.

id guess 13-14psi would net you about 420rwhp. But if your gonna stay with a boost that low, then the t78 is WAYY to big of a turbo for that. Get a sp57 and enjoy the insta-spool.
 

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Supralicious
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Discussion Starter #3
Thanks for the reply.
Do you think that 18psi is too risky?
I've heard of 15psi, but 18? Can someone that has a T78 chime in and let me know how high their boost goes up to?
 

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1st Lieutenant Team BEYAW
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mr2jzgte said:
Thanks for the reply.
Do you think that 18psi is too risky?
I've heard of 15psi, but 18? Can someone that has a T78 chime in and let me know how high their boost goes up to?
ummm, maybe i am reading this wrong.....but this is for a Supra right? a T78 can easily be tuned to over 30psi......but like ScrewDrvr said (sorta) i would stick to a smaller turbo or save until you can upgrade the fuel system at the same time there isnt any reason to run that big of a turbo and only run a max of 13psi :eek:, at least not that i can think of
 

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Lets go Nets
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Id run a max of 17 psi at the most. T78 is a huge turbo and makes ALOT of power.

FDBP mod should allow for 500rwhp.

Brett
 

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Supralicious
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Discussion Starter #6
Thanks for all your replies.

ToyoBeastly, what I had said was that 18psi could of been too high for the engine being that I would run stock fuel.

neonafk thanks for the advice. I really appreciate it. BTW, how much are you dynoing? Do you have the FDBP mod?
 

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Why would you want such a slow spooling turbo? Why not go with SP67 GT HO or SP67 P-trim? Same power, quicker spool?

Joe
 

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I had a stock fuel T-78 dyno at 522 RWHP at 19 lbs .I ran 15 lbs on the street normally.Did fd mod later n o real difference you could feel.
Why run this big turbo and low boost?Still pulls way harder than a twin stocker.
Slow spoolling my ass Mr. Palm Harbor come on over for a SLOW ride sometime.
Now fuel,alky ect ,but was alot of fun even at low boost.
 
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My T78 spools very closely to the stock twins. I certainly don't need to raise the rev limiter, and the big ass A/R means the power won't fall off in the high rpm range like the faster spooling turbos.

You just can't go wrong with this turbo. Fitment and quality is excellent. Some of the competetion looks good offering a higher grade steel header, but when you jet-hot extreme 2000 coat it, it's going to last forever anyway.

Btw, I did 490whp at a little over 15psi and no fan on the FMIC, 95degrees, heat soaked . So be careful. One vacuum line coming off or any other minor issue and you'll be hurling rods through the block. This is a strong turbo.

It's a re-post, but I love this pic ;)

 
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wtf, as long as I'm posting pics...

This isn't a repost. Look at that header. Don't go ceramic (like some of the kits offer)...jet-hot all the way!

 
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Oh, and someone replied a T78 can be tuned over 30 psi. It actually maxes efficiency around ~28psi.
 

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1st 2jz 240 swap EVER
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someone mentioned the sp67 further up in the thread, i was wondering if its true that it will make the same amount of poer as the t78. i am looking to make around 600 rwhp on 93 oct and its gonna be a daily...which turbo would be better the 78 or the 67 thanks Dane
 

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Oh I think they like me.
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95240sx-2jzgte said:
someone mentioned the sp67 further up in the thread, i was wondering if its true that it will make the same amount of poer as the t78. i am looking to make around 600 rwhp on 93 oct and its gonna be a daily...which turbo would be better the 78 or the 67 thanks Dane
I dont think either turbo can achive that... safely on pumpgas...

maybe 101 pumpgas and 23psi :)
 

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I run mine off the wastegate spring at slightly
over 15 lbs. My particular set-up is very laggy
from a start(auto w/stock tc), but it is a blast
from a roll. 60-130mph sprints are very fun even
at this low boost level. I'm looking at a meth/water
kit to up the power slightly. Nothing major, about
18-19 lbs still off the wastegate spring. I really like
this "old technology" turbo so far.
Wayne
**I forgot the dyno #'s. 428 rwhp at 14.5 lbs.
 

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I know the highest. 578rwhp on the stock fuel system. T78. Done by Larry at Autotuner. Car was tuned with a wideband and the af's were still at a safe range.
 

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Lets go Nets
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mr2jzgte said:
Thanks for all your replies.

ToyoBeastly, what I had said was that 18psi could of been too high for the engine being that I would run stock fuel.

neonafk thanks for the advice. I really appreciate it. BTW, how much are you dynoing? Do you have the FDBP mod?
Im not running a T78, but im dynoing around 455 rwhp @ 18 psi in this weater now. no FDBP yet either, Im not going to need that unless i surpass 475rwhp, in which the stock fuel system starts approaching its limits. good luck on a turbo selection

-Brett
 

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Oh I think they like me.
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lessthanryan28 said:
I know the highest. 578rwhp on the stock fuel system. T78. Done by Larry at Autotuner. Car was tuned with a wideband and the af's were still at a safe range.

Done with pumpgas ? what boost?
 

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My thoughts on the T78-

I installed my kit this past May. I was running stock fuel for a little while and found the turbo to have some kick ass power. I monitored my a/f with uego wide band. Note I kept boost at 1 bar, which was being regulated by my waste gate spring via a steel braided line. This turbo pulls like a mofo to redline and makes me wonder why I stayed on stock twins so long???

Spool up is around 4200rpms vs. 4000 in TTC. Power difference on pump gas? NO contest, the 78 at 1 bar of boost vs my stock twins at 20lbs and race gas. The 78 makes more power, well at least it feels that way in the drivers seat.

The SP67GTQ HO is a faster spooling turbo with similar peak power, if not more. Cost of course, is more.

*I'm tired of hearing one boost spike and the motor is gone... Run it off of the waste gate spring and its 100% SAFE. If you want to boost more than 1 bar then tighten the spring. You can't go wrong. Don't forget to use a steet braided line from the waste gate.

Good luck with your choice.
 
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