Switching Turbos: Hx35 to gt3076r

[kloucks]

About three months ago I finally finished my M50 turbo e30 project. Currenlty running lower compression with a .140" MLS and a holset hx35 with the 12cm housing. It dyno'd at 380 whp at 18psi, and as a daily driver it is a beast, but i would like to have quicker spool up (doesn't everyone). I recently blew the turbo seals so i have it out for a rebuild, so now would be the time to upgrade to a BB turbo.

My question is: If i upgrade to say a gt3076r or gt3071r with a .63 ar, or possibly a .82 ar, would i be disappointed in the lack of difference in spoolup time? I should mention that my max hp is probably 450 or so.

[cleanasse30]

If you are looking for faster spool I would go for a .63 A/R turbine housing unless you have a divided manifold, then I would opt for the .82 A/R. However I have no direct experience with either, my suggestion is based purely on what i've read doing research while planning my own turbo build. Just my $.02

Nice looking setup though! When were you seeing full boost before the turbo seals blew?

[kloucks]

I just check some of my old logs and it looks like i was reaching 15psi around 3500 rpm. Which is not shabby, but would the switch to BB get me there by 2800?

[cleanasse30]

I would guess 3-500 rpms sooner, depends if you get a billet wheel too. 3500 seems like a good place to be for spool to me though, 3k would be nice if you do mostly street driving

[e30 gangsta]

why not go gtx3076r?

[kloucks]

I could put the extra 600+ bones to other use. And the garrett could still leave me wanting more.

[GunMetalGrey]

Are you running an oil cooler or do you have an oil temp gauge?
I only ask because I am having oil temperature issues on basically the same setup as you.

[speedracer 2002]

Why do you want faster spool? A 3076r will spool pretty quick on a m52 if you get a gtx you'll see an even faster spool time.

[kloucks]

I'm not running an oil temp sensor, or an oil cooler. I think at least the temp sensor will go in this winter. I do get the feeling that these holsets tend to heat up the oil a bit, and even with a bigger radiator and a 92 thermostat it sticks right at 95 most of the time.

I think I will end up going to a BB this winter, just for the fun of it.

[GunMetalGrey]

May want to check your oil temps, Holset states that the oil temp should under NO conditions should exceed 248 degrees F, and I have been seeing oil temps of 260 degrees. This may be because of how my drain line is routed/plumbed ( a lot of metal right near the manifold) but it would be worth checking into!
BB should be fun!

[BMWManiac]

Let me know if you want to sell that HX35 after the rebuild

[LowR3V'in]

I have been seeing oil temps of 260 degrees

Where are you measuring at?

[GunMetalGrey]

Vanos oil feed, non vanos engine.