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Discussion Starter #1
I have Greddy t78 kit and it spools way to slow for the track. I get full boost by 5000 or so. What is a good setup for the track? I was thinking of a BL t61 kit. Anyone have experience with this? How is the quality of the kit? Can I do something to my T78 kit to make it spool faster without buying a whole new kit. I don't want to spend more than $1.5K to switch.

thanks

joe
 

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57to mid 60 mm turbos seem to work well on road course. Find the courses you like and try to match the turbo to the courses.Smaller tighter track samller turbo.
Longer faster track larger turbo.
 

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I have a T78 as well. I ran Thunderhill and you must be conscious on your gear to rpm.
 

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call kean at boostlogic. he can tell you what you need. I suspect all he will recommend is switching your turbo.
 

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I have a t78. I would get the gt35r. It comes with the .82 t4 and you can get it in v-band for free. I ordered mine without the anti-surge housing from atpturbo. The problem with the t78 is it hits too hard and makes your body tired fast. I rather have some turbo that is more smooth in power delivery.
 

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The gt35r is not well suited for road race aplications.
 

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The turbo is too large unless you are running a banked oval or a straight 1/4 mile.
If you like to turn get a smaller turbo that spools in the 3000 range and has more linear power.
 

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Leh has shown us that a 67mm turbo can do great things in the right hands. It's thanks to impressive videos of him (and other experienced road racers) that lead me to consider larger turbos than ever before. Keep in mind that a 67mm turbo is REALLY large by my personal standards. ;)
 

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Steve Theodore said:
Leh has shown us that a 67mm turbo can do great things in the right hands. It's thanks to impressive videos of him (and other experienced road racers) that lead me to consider larger turbos than ever before. Keep in mind that a 67mm turbo is REALLY large by my personal standards. ;)
I went to Little Talledega last weekend (1.3 mile, twisty, top speed ~100-105 mph in my car, much less in slower cars), and the 67 wasn't totally happy in the tighter corners, although again it did about as well as my previous older gen T61. Of course, I was held down by street tires, which limited my corner speed, which limited the rpm I was at as I entered the straights, resulting in lag. A BPU or 58 would really be better suited to such a track, but my ownership is not based on small, low speed tracks. I don't particularly like such tracks and the Supra doesn't either, it was made for high speed. :D I can say that I at least pulled everyone on the straights at only 18psi, including some highly modded/stripped track cars, only I drove my car 130 miles to the event with ice cold AC at 25 mpg and they trailered theirs. :)

I DEFINITELY wouldn't use larger than .68 a/r for the 67mm if you like to road race places tighter than Road Atlanta. I wouldn't want smaller than a 63 to 67mm for RA or the majority of tracks that are "Supra Friendly". Really tight tracks will never be the Supra's friend unless perhaps you are BPU or 58, which IMO compromises the real strength of the car----high speed acceleration. But for some, that compromise is worth it, that's a personal preference.
 

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I have been contemplating this question for quite some time, and have arrived to the conclusion that for my level of skill, I will go T-61; once I have acquired 25% of Leh's skills, I will go 67+fuel. The tracks that I frequent the most are Road Atlanta, TWS and in the near future MSR houston, so they will all be amenable to both set-ups.

Cheers
Rich B - whose new goal in life is to shift into 6th at Road Atlanta
 

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I have been dieing to go to a road course with my car. Sadly, Limerock is pretty much booked until October, so that is out of the question(SCCA events I believe). I was looking at Watkins Glen, has anyone ever been there?

I have a T-58 turbo, aka TS04, and I just bought a fuel system and I wanted to go to a SP67 turbo with the smallest a/r they have for midrange power, but before I do that, I wanted to get some time in the track with the T-58 to see how the car is with that setup.

The best thing about this turbo is I have 500rwhp+ and 470-480 torque at 21 psi, and I have full boost by 3800 rpm!

I saw a guide on how to make a custom camera mount on the back support of the rear seats somewhere, so I'll probably do that soon and I'll record my laps and post them on the site to show people how nice this turbo is.
 

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The Glen is a terrific track for the Supra and your turbo will do well there with enough corners that reward quick spool and a strong mid-range. Just don't plan on setting any new track records first time out...it's not a very forgiving track if you put a wheel wrong.

Bruce
 

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bart97 said:
The turbo is too large unless you are running a banked oval or a straight 1/4 mile.
If you like to turn get a smaller turbo that spools in the 3000 range and has more linear power.
I guess it depends on driver preference as Leh said, but in my opinion you would only need full boost at the lowest RPM you are running on course. If your not seeing 3000RPM while racing what is the point of having full boost by then, you are just giving up extra power at high RPMs.
And if you are seeing 3000RPM, wouldnt that just mean that you are in the wrong gear considering that most supras use ~7200RPM redline if not higher?

Brian
 

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Brian-

You're bringing up something that is in my opinion a big mispreception here. People are talking about minimum full boost rpm when really what they are talking about is turbo response.

at a given rpm, we'll say 5000, a T61, a T67, and a T99 or whatever is the popular dyno fag turbo now days, are all over thier minimum rpm for full boost. go from off throttle to full throttle, and the smaller turbos will (generally) respond the fastest. It is MUCH easier to drive a supra whose power comes on when your foot hits the gas. The power is also much more linear with the smaller turbos. This isn't a big deal on the freeway as you can hit the gas and wait... But exiting a turn, you want a a certain amount of power, not all of it. And its harder to regulate this with the big turbos.

A high horsepower supra is a handful on the roadcourse. Good drivers can make them quick. But I'd be willing to bet that most people here would actually be faster around a medium speed roadcourse with a small turbo, that one that makes 300 more rwhp.

heavy cars with lots of power that comes on unpredictably, and non linearly, can be pretty frustrating.

Matt
 

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I agree with what Matt said except in my lay ...or lame... mind I would use the term "throttle response" rather than turbo response just because to me it is more clear what I want.

When I got my first turbo car ('90 Mitsu GS-T) I hated the delayed throttle response compared to say, my old '67 XKE which had instant throttle response. Eventually, I learned to compensate for it. Then with the Supra too, but fortunately in sequential they are reasonably fast responding. Even though I just opened the box a few minutes ago and have a shiney new PHR Stg1 on my desk, I'm still concerned that the throttle resonse I'm giving up will make me initially disappointed until/unless I can learn to compensate again ...of course that's fantasy since I've never driven a single Supra on a roadcourse yet.
 

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I've got a sp58 ball bearing turbo and it rocks on the road course. Watch my vid from watkins glen in the road race vid sticky in this section. That is me with stock fuel, 13psi on the sp58 hitting between 140 and 150 on the back straight.

That little turbo is amaizing.

Mike
 
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