I have been searching around trying to decide what size I want to go with when I pick a new turbo up this winter, I am wanting it to be full boost by 4k and hold to at least 7k. I have read anywhere from .83 up to 1.25 or 14cm^2 up to 26cm^2 if you like to measure that way...

Car is S4 turbo, stock ports, 10k since I rebuilt it, with 80-90psi on all faces.

Any recommendations?

Keith

 

Assuming you're wanting to use a P-Trim, full T4 setup, I'd use a 0.81 to 0.84 A/R.

B

 

Not sure about the trim, one thing I haven't looked into, whats the differences? But yes t4 of course.

 

If it's a full T4, use a P-Trim setup with that A/R listed. You'll like it.

B

 

I had a 62-1 p-trim with the .81a/r and it would kick hard around 3800-4000 and spin way past the 7k mark. That was a fun streetable turbo. Car dynoed 347 @11psi on it. Now i got a laggy
T-78 that makes the engine want to spin way past the 9k mark in a heartbeat!!!

 

go with a divided turbine housing and divided manifold as well

 

Depends on what compressor and turbine wheels, and how much power you are looking for.

 

Well I have been looking at the Holset HX50 or 55 for example... That is one of the possibilties. I would like to get close to 400whp now and have a turbo that is good for more than that for the future.

 

if u want 400whp then a hx40 will suit you better. faster spool and plenty capable of hitting 400. but if u want more than a hx50 or hx52 youll want, but they only come in a flange between the sizes of t4 and t6( its not quite either size). i think with supporting mods the hx40 will be capable of 450whp if u push it. i should be pretty close to 380-400whp tuned by BDC at 16psi on my hx40 on stock port 13bre. the big question is, do u plan on running only pump gas?

 

I was thinking about an hx50 or 52 that way I could get to my 400 hp now and have room left for more later. I already have a meth inj kit on the car, so yes I want to stick to pump with water/meth injection.

You say a hx52 would take longer to spool. Is that true if it has a 16cm^2 (.83) a/r housing?

 

Just keep in mind the physical size of that Holset turbo.

B

 

Is 14 really .83 and 26 really just 1.25? Kinda imagined it was bigger, swear 7 or 8 was about .63?

 

Actually16cm^2 is .83A/R... And if I remember right 26 is close to 1.25.



So you guys think the hx52 would spool by 4k? I am wanting one that will boost fast and hard. Not slowly build boost...

 

So you guys think the hx52 would spool by 4.5k? I am wanting one that will boost fast and hard. Not slowly build boost...

 

an hx52 is a huge ******* turbo dude.

get a 62-1

 

Gotta be big for big power....