Hi,

I know what i want from a turbo

makes about 180-220rwkw at 12-15psi
spools up INSTANTLY!

I don't want big power. I want fun, manageable power that is on tap as early in the rpm range as possible.

I could go for a custom TT set-up with 2 tiny turbos, but that is alot of stuffing around hunting for the appropriate parts cheap.

I am thinking of a small GT ball bearing turbo..

What turbo from the GT bearing range meets the requirements I have?
200rwkw at reasonable boost as INSTANTANEOUSLY (i really can't emphasize that enough) as possible?
HKS GT25?

Any suggestions on the correct turbo for my needs would be appreciated, as I am not fluent in the lost turbo-spec dialect.
the engine is a stock S4 13BT if that helps.
I was kinda hoping the turbo settled on would have an internal wastegate too. The GT range do have internal wastegates don't they?

Many thanks in advance,
Perry Gehenna

 

GT25 is a complete waste of time.. it'll run out of puff at around 4000rpm!
We use those on Sr20s as a 'drivable' turbo.

The only was to use them would be in a twin setup.

Do you want to go backwards from the std turbo setup???

 

that's just it, i don't really know what the specs mean.
i was just hoping that someone who had a working understanding of the GT ball bearing range of turbos could tell me what turbo would meet my needs as I listed them. a GT25 is obviously does not meet the criteria I describe in my post. What does? advice is welcomed!!!

I should have titled my post better, I asked admin to change it, but "no cigar" as yet.

Taa,
Perry Gehenna

 

Get a GT 28/35 ball bearing, it will get 300RWHP @ 15psi easily enough and spool up real quick. Probably would be in between the stock twins sequentially and the stock twins non sequentially.

 

TDO6 20g with a 14 actuated exhaust housing. Instant boost, falls on its face after 7000rpms. Good for 325-350rwhp and lots of fun at 15psi on an FD. The GT2835 might get you around the same performance, but the biggest actuated housing they have is AR .86, and you need the AR 1.12 with that small of an exhaust wheel.

 

Instant power is something a Supercharger is Known for not a turbo charger. Exhaust pulse spools up a turbo so it takes some lag time to get boost. A Supercharger runs off a belt and is making boost at idle and has instant response. Although Turbos are superior as far as overall power output it seems you are interested in Low end instant power of a supercharger rather than lag time it takes to boost a turbo up. Maybe thats your answer. Was the stock turbo spooling up too slow for you? Keep in Mind the M2 performance twins used twin GT30 turbos on thier Stock upgraded twins for the FD3S Model. A GT25 is just too small. I think you may even be in the wrong car. A rotary is short on Torque. Especially low end torque. It uses higher RPMS and Big laggy turbos to make the outstanding performance you see. Now a Large Displacement Engine like a V-8, V-10 etc will have instant power low in the RPMs and insane fun tire ripping torque. if you have ever driven a C-5 Corvette or a Dodge Viper or Shelby Cobra , Ford Mustang/Cobra you will know what i am talking about.

 

maybe a garrett T04E with a 57 trim wheel, wet CHRA, with an A/R of around .84 to 1.00 would be good.

 

From personal experience, with the S4 motor, and a variety of singles. A .60 compressor, and a .81 P trim hot side TO4S on an HKS cast manifold(on a street ported motor) will give you instant spool, and around 350rwhp. It is the same as a V8, instant, light the tires from 2750rpm on up. Carl

 

I have the GT3540 with the .86 A/R. (The small GT, I guess.) It spools instantly, and I get 320 rwhp. My car is a blast to drive, more like a V8 than a turbo. It is way more responsive than it was with the twin turbos.

 

Thats interesting, I wondered how the smaller one would work.