Turbo Questions(Long)

[02_silver_wagon]

A few questions I am having while searching for a turbo. My plans are 300-350whp at 10-15psi daily and 400+whp on 16-20psi on the weekends/track. I will have proper fuel/tuning, maybe a built block it will be fun to see the strenth of a stock KA. My plans for the car are to have fun, learn how to drive/tune, and maybe beat a few V8's on the weekend.

I was originaly going to go with a HKS GT3037 or comparable turbo because it would hit full boost by 3500-3700rpm which is mandatory for any turbo I decide to choose. I started thinking about Full races t3/t67 because of the good spool and huge hp numbers. Then I started to think about an off company GT technology manufacture. I have been thinking about Precisions Sport Compact GT turbos.

My question is looking at this graph What turbo whould be equal to the GT 3037? Would it be the GT37 or the GT30R?

I saw the GT35R and people on the Evolution forums are saying they hit full boost by 4200-4300rpm. So on a KA it would be about 3500rpm. It would also provide a whole lot of horsepower and better effeciency ratings than the 3037. So would a Precision GT35R variant turbo be the best bet for me?

A few other questions. This was posted on the Evo forums and I wanted to know if it was true/accurate.

Quote »Greddy turbos use thrust bearings, so will last longer than the ball bearing types.There will always be conflicting studies, but ball bearing turbos are weaker then non bb. I know that from personal experience, from my friend who is a rally driver in europe. He drives group N rally car, and JUN engineers said the same thing, I have no reason to dubt those people.BB spool only a little bit quicker, its not really noticable difference, despite what most people here think.

non ball bearing turbo evo82600 rpm 0 boost3000 rpm 0.5bar3400 rpm 1.35

ball bearing turbo evo82600 rpm 0 boost3000rpm 1bar3200 rpm1.35bar[/quote]

I always thought full BB turbos like the HKS/Garrett GT turbos showed quite a bit better performance than any t3/t4 turbo. Is there really that little of a difference?

Anybody have a compressor map for the GT35R with these specs?

GT35R

Compressor:- Wheel Dia - 82mm- Trim - 56- A/R - 0.70

Turbine:-Wheel Dia – 68mm- Trim – 84- A/R – 1.06 or 0.82

Because all I can find are the ones for the 68mm 56 Trim .70 A/R

Thank you for reading all this and helping me out.

[Projex240]

Not really. The biggest differences so far are the trim/a/r matches they use. Also..they are abll bearing...so hitting full boost even at 3500-4000 should be no problem. The gt uses a larger a/r turbine housing on thier t3 turbos. Its a .82 to complement the gt's ceramic wheels and BB center section. Being setup for such quick spool, they can afford to run a larger a/r turbine housing. They also ahve the option of using a ballistic center section that houses the wastegate right onto the turbo's turbine housing and not the manifold. Its very trick and gives GREAT response. We put one on a very good friend of mine's GSX. CRAZY spool up. HE can build boost it idle to 12 lbs with no aftermarket ignition. With this turbo...his car made 440 to the wheels with no nitrous on 21 lbs. Granted, he has the supporting mods to handle that kind of power. But he also hits full boost on 8.4 cr on a 2.0 liter by 3600 rpms. Very impressive turbos if they arent too extreme. Even BB can get laggy if not matched properly with your setup.

[hannibal]

Check out Performance Techniques site. They have some wheel and housing specs for the GT turbos. http://64.225.76.178/gtbb.htm

[C-Kwik]

It would be more helpful to loo at thr compressor maps for each of the turbos to detemine the best match.

As far as spool up,just an fyi...the more you boost, the longer it takes to reach full boost. The turbo's response will be the same, but since the turbo has to get to a higher boost, it needs more time to spool up ehough to flow that much air...

[02_silver_wagon]

It would be more helpful to loo at thr compressor maps for each of the turbos to detemine the best match.

As far as spool up,just an fyi...the more you boost, the longer it takes to reach full boost. The turbo's response will be the same, but since the turbo has to get to a higher boost, it needs more time to spool up ehough to flow that much air...

I realize that boost affects spool.

I am looking for a compressor map with these specs and I can't find one. Does anybody have one or know where I can get one?

GT35R

Compressor:- Wheel Dia - 82mm- Trim - 56- A/R - 0.70

Turbine:-Wheel Dia – 68mm- Trim – 84- A/R – 1.06 or 0.82

[KApwr]

Quote »I am looking for a compressor map with these specs and I can't find one. Does anybody have one or know where I can get one?GT35RCompressor:- Wheel Dia - 82mm- Trim - 56- A/R - 0.70Turbine:-Wheel Dia – 68mm- Trim – 84- A/R – 1.06 or 0.82 [/quote]

In regards to the power goals and turbo response that you're looking for, the GT30/35R would be a little overkill for that. You can get exactly that from a T3/T04E (50-60 trim, .63 A/R) and for cheaper too. If you don't want to limit yourself to 400-450whp then i would seriously consider getting an SC61. This turbo will spool a little later but is flexible enough to support 300-600whp. It uses the same compressor wheel as the GT35R. A GT30 is the exact match as the HKS GT3037 (52trim) as far as center section goes but the HKS comp/turb housings are different. Here is the compressor map you're looking for and also you can find it on Garrett's website. Good luck with your project.

[02_silver_wagon]

Thanks for your help KApwer. You have an interesting point with the SC61. I'm confused what the compressor side of the turbo is like, because you said it was the same as the GT35R but I can't find a GT35R with a 61mm wheel. Can you find me a compressor map?

What kind of spool would the SC61 have? What do you think about the SC52?

[KApwr]

The 61mm is the measurement of the inducer of the compressor which is equal to 2.4", you're confused because you're comparing the exducer of the GT35R which is 82mm but if you look at the SC61 exducer= 82mm(3.22"). Trust me, they use the exact same compressor wheel, this wheel is also known as the GT40 56trim. The GT35R benefits over the SC61 are BB center section and the turbine wheel is of GT technology while the SC61 uses the T350(stage 5) or T04 Ptrim. The SC61 will prolly make full boost by 4000-4200rpm. I would go with the SC61 because it utilizes the GT technology compressor wheel. IMO best turbo for the buck and it has been proven to make tons of power.

[02_silver_wagon]

Are there any other SC turbos you would reccomend because I REALLY want full boost by 3500-3700rpm.

[KApwr]

Are there any other SC turbos you would reccomend because I REALLY want full boost by 3500-3700rpm.

I don't have any experience with the rest of the SC lineup but the SC50 is the same as a T3/T04E 50 trim so I would go with that if you want boost to hit at that rpm.

[absolute]

thats nice info man i was lookin at some turbo stuff this week too, and was wanting to get into hks as opposed to what everyone else is doing, hey kapwr gimmie a holla