Updated: Pics on post #28. Billet turbo with SP Quick spool valve.

[tekdeus]

Some cool new turbo innovations have recently become available, and I am just about to buy a new turbo kit. I currently have a stock 3.0L 7MGTE with BPU mods supporting up to 500+ hp, but currently making 393rwhp on a basic upgraded CT26 turbo.

The car is street-driven 99% of the time, and I'm interested in 475-550 rwhp on the street with meth injection, and the fastest spool possible. I will be running the Sound Perfomance quick spool valve for even faster spool (info here: http://www.sound-performance.com/p192/Sound-Performance-Quick-Spool-Valve/product_info.html)

I'm also looking at using one of the new billet turbos, since the lighter weight aluminum compressor wheels are shown to spool much faster.

So I will have 3 things on my side to support some very fast spool:
SP T4 valve
Ball bearing CHRA
Billet compressor

Typically, a lot of supra owners might simply choose the GT35r, for a good balance of fast spool and top end power, often with a .63 or so A/R, making around 500hp. I was thinking of going with a .83 so that my effective A/R with the valve closed would be around .4 for fast low-rpm spool-up, and offering more top end power. Forced Performance offers a modifed "HTA" GT35r with their own higher flowing billet wheel and compressor housing that has become very popular with the 4-cylinder crowd, with lots of dyno sheets out there showing faster spool and more power than the GT35r. Precision also makes a billet 62mm turbo, but so far does not seem to have one with the GT35r-sized 68mm exhaust turbine with a divided T4 housing, only a 62 or 76mm turbine. I'm thinking this HTA turbo with the SP valve should really outspool the GT35r and make up to 550hp? It is rated to flow 70lbs/min, compared to the 60-65lbs of the GT35.

Also, the HTA billet turbo is available with a 86mm (exducer?) compressor size instead of the 82mm on the regular HTA turbo and GT35r. It is rated to flow 80lbs/min compared to the 70lb of the HTA and 60-65 of the GT35r.

Just thought I put this info out here to hear some feedback from you guys, since this combination has never been done before on a Supra as far as I know. Any thoughts as far as possible negatives? Which specs would you choose? I don't see how it can be too "spool happy", considering how the stock turbo is so small and fast spooling. Could there be any potential surging issues with the valve closed? Should I consider a 1.0 A/R? Or even look at a billet GT37 style turbo? This is my first turbo purchase, and I'd like to make the right choice the first time.

My goal is to do forged internals/cams/porting/oversize valves/standalone at the same time, but we'll see how rich I am first, and may have to do that later, and be careful to not blow the stockers.

(P.S. My car has room for 345 drag radials in the rear. I think it would be awesome to hit full boost very early in 2nd gear with 500-550rwtq.... and fully hook up! How much power could a drag radial of this size put down, by the way?)

Cheers - Brad

 

[tissimo]

71 billet, or maybe the 74 ( not sure if its out)

 

[becauseican]

Ball bearing T67...wicked turbo on the 2jz, can do 700 whp, and spools quick already, they are known for doing 500 whp at around 18-20 psi on pump gas. Run a .68-70 t4 housing.

Give me a call, I can get good pricing on turbos, and would like to put togeather a 7m turbo kit package, I am also a Haltech dealer so I can hook you up with a sweet EMS.

 

[Justin727]

I would have to agree with Randy! I have a PT67 on my 7M and I've very eager to boost the SOB!
But if that valve works the way it's suppose to I was go with a 72 with an .81 hotside if at all possible.

 

[IJ.]

If the Valve works as advertised a 1.14 divided on a 67 would be the shot as it should spool like a .84 but be able to breathe in the upper rpm ranges.

 

[Zazzn]

67 is my vote as well unless you get one of the comp turbo Triple ball bearings.

I love my PT 67DDB with the H cover (lil extra power) and .70 housing with cams.

With the spool valve oh man I would really wet my pants... I get lots of boost in first and 2nd and spin the tires even in 3rd! (by just stepping on it)

Made 647 @ 24 PSI with water/meth and pump

 

[NashMan]

i have 67 as well took me a along tiem to find a trubo i liked mine tad diffent thou

 

[QWIKSTRIKE]

The gt4082 is a verry fassst spooling turbo that will give you up to 500rwhp for sure. I will make full boos in the early to mid 3k range and spool by 1800-2100 range depending on mods. For the stre it is an ultimate turbo. I like my gt4067r, but feel the need to go with more power so i may trae it in for a 74mm turbo!

 

[tekdeus]

What do you guys think about this turbo that is rated to flow like a T67? It is another modified GT35r with a larger compressor wheel: http://store.forcedperformance.net/...n=PROD&Store_Code=FP&Product_Code=NTGT3586HTA

Any potential issues running a compressor with that much flow and an exhaust turbine that is still 68mm? Which has more effect on exhaust flow, turbine size, or A/R?

 

[tissimo]

What do you guys think about this turbo that is rated to flow like a T67? It is another modified GT35r with a larger compressor wheel: http://store.forcedperformance.net/...n=PROD&Store_Code=FP&Product_Code=NTGT3586HTA

Any potential issues running a compressor with that much flow and an exhaust turbine that is still 68mm? Which has more effect on exhaust flow, turbine size, or A/R?

What are your goals really? Honestly though, I'd go 71mm billet DBB with a .96 a/r (or there abouts).. Spool fast, make lots of power, and rock out! 2jz Guys said the 71 billet spools like a 67.. add the SP Valve to make it spool close to a 35r, and make 750-800whp.

 

[tekdeus]

My goals are:
- widest powerband possible / area under the curve
- pulls all the way to redline with minimal to no tapering off
- maximum power that can be put to the street on really wide tires or drag radials, with minimal pulling of boost in 2nd and 3rd gear
- maximum street fun
- drag racing later on, but not a priority.

Question: If the smaller 68mm turbine spools the turbo faster than say a 72 or 76mm, but restricts top end exhaust flow/power, could this be overcome by running two wastegates? Two smaller Tial's are only a little more expensive then one bigger one.

 

[Slow66]

Question: If the smaller 68mm turbine spools the turbo faster than say a 72 or 76mm, but restricts top end exhaust flow/power, could this be overcome by running two wastegates? Two smaller Tial's are only a little more expensive then one bigger one.

Not caused by the wastegate. Its indicative of too small a turbine or a/r. A 67mm with a q-trim, and a .96 a/r or even an .81 a/r will have no issues pulling to redline for your setup. I wouldnt go crazy and oversize the whole turbo just because you have the spool-valve. Pick a compressor that falls in line with your power goals at a certain psi, and then chose a larger turbine & a/r combo than normal because of the spool-valve. I would also wait a few months to see how the long term durability is of this spool valve on someone elses combo. I dont know if any subtantial long-term testing has been done on them....

 

[tekdeus]

Not caused by the wastegate. Its indicative of too small a turbine or a/r. A 67mm with a q-trim, and a .96 a/r or even an .81 a/r will have no issues pulling to redline for your setup. I wouldnt go crazy and oversize the whole turbo just because you have the spool-valve. Pick a compressor that falls in line with your power goals at a certain psi, and then chose a larger turbine & a/r combo than normal because of the spool-valve. I would also wait a few months to see how the long term durability is of this spool valve on someone elses combo. I dont know if any subtantial long-term testing has been done on them....

Does a standard GT35r pull to redline? I'm wondering if the 68mm exhaust turbine and .83 A/R will flow enough for that. Yes, the spool valve has been tested by the creators, but I still would like to have a streetable turbo in the worst case scenario that the valve doesn't work out for some reason and I have to either remove it or leave it open.

Also, if I extend the redline in the future with lightened internals, is there a certain RPM where it would start to choke? Thanks for the feedback btw!

 

[IJ.]

Mine with a 1.06ar would flatten out after 7500.

 

[Nick M]

The gt4082 is a verry fassst spooling turbo that will give you up to 500rwhp for sure. I will make full boos in the early to mid 3k range and spool by 1800-2100 range depending on mods. For the street it is an ultimate turbo. I like my gt4067r, but feel the need to go with more power so i may trae it in for a 74mm turbo!

Is it the top end pull you prefer to the 3582?

 

[Nick M]

What are your goals really?

The car is street-driven 99% of the time, and I'm interested in 475-550 rwhp on the street with meth injection, and the fastest spool possible. I! How much power could a drag radial of this size put down, by the way?)

Cheers - Brad

:biglaugh:

I think his goals are typical. I myself don't need that much top end.

Mine with a 1.06ar would flatten out after 7500.

And mine with an upshift at 5800?

 

[tekdeus]

Well I'm 95% sure I'd like to buy this turbo http://store.forcedperformance.net/...oduct_Code=NTGT3586HTA&Category_Code=Turbo-FP
It is a GT35R with a larger (62mm ind., 86mm exd.) custom billet compressor and housing, that is rated to flow 75 lb/min (same as a T67).

I received my SP quick spool valve, and another SF member who also bought one told me that his valve starts to open at 7 psi and is 90% open at 12-13 psi and fully open at 15 psi. Sound Performance told me that the valve begins to move at 5 psi.... fully open by 11-12 psi....

I'm hoping that these high psi numbers needed to open it won't cause it to choke. I was torn between running a .68 A/R and a .82, but I think a .82 may be better since the valve will be closed 95% of the time the way it is.

What do you guys think?

 

[IJ.]

I predict stupid amounts of tire smoke

 

[NashMan]

i run a t67 70 a/r and bmg 68 a/r shoudl be good for 7000 ish i think you will be ok


and i whould not bother with 2 wastgates in less you header is made for it or if you are chokeing a 50mill waste gate

witch whould be pretty dame high in the holly shit meter

 

[sk6471]

Tekdeus, I understand why it is so hard to buy a turbo for a Supra. Different turbo companies excel at different things. If your turbocharging a domestic V8 you need a turbo that's more efficient at lower pressure ratios with lots of flow. That's where Garrett GTs are best. If you have a small four-banger, you need a turbo that can spool quickly with little flow and still be efficient at higher pressure ratios. That's where FP seems to excel. Our needs are some where in the middle.
I personally believe that the advantages to the Forced Performance products are only at higher boost levels. Honda owners have to pull 35 psi to make any power. Because you have more displacement, you don't. For the money your about to spend I don't think you will get much in return. Also Garrett GT turbos use water line as well a finicky oil lines all of which have to line up at proper angles to flow right. So picture all of these lines, vacuum hoses, and couplings plus whatever is required for the quick spool valve all crammed under and around a medium framed turbo.
I also think that Ian is correct about wheel spin. If you have to have a turbo that spools early and holds all the way to red line, you probably want a turbo that doesn't hit like a freight train and spools in a slower more predictable manner. If you can get a good deal on a large older designed BB turbo, you should probably take it.
Here are some links for you. The first is Garrett's take on billet compressor wheels and the second is info on the GT37R.
http://www.turbobygarrett.com/turbobygarrett/news/race_updates/Garrett_Fully_Machined.html
http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT37/GT3788R_772719_1.htm