View Full Version : Turbocharger selection

03-09-2005, 08:04 AM
I'm meeting with my fabricator this weekend to talk about how we are going to plumb the system on this car. I'm still struggling on turbo selection however.

I'm not sure if we are going to have room to go with twins because of drivers side. The brake power booster, power steering lines and upper control arms will likely interfere with the exhaust plumbing. I don't for see a problem plumbing from the heads to the turbo, but room for the downpipe would be extreamly short.

With that said I may end up going with a big single. It's nearly impossible to kill the low-end on a 455 so I'm not worried about loosing low-end on a big single application. My problem is still in sizing. I'm looking to push between 650-700 which should be about the limit on pump gas with this size motor.

What turbo would you guys recommend for both a twin application and a single. My RPM range is 2000-6000 on the motor build. I would like to reach full boost no later than 3500 rpm. My stall speed is 2800-3000 on the tranny, so full boost closest to these rpms speeds would be ideal.

thanks in advance.

Travis B
03-09-2005, 09:08 AM
As far as I know Turbo sizing is very very important and those decisions I tend to leave to the professionals! I would call GARRETT or turbonetics or whoever you plan on buying a turbo from! I am like you I think twins can get very cluttered in a smaller engine compartment or when other componets get in the way! :idea:

03-09-2005, 03:57 PM
Will this be on pump gas?


03-09-2005, 08:18 PM
A single T76 should make that horsepower easily, or even a t88 at lower boost levels for less heating of the air. For twins, a couple t61's will make way more than want, but will still spool up quickly.
Dont get caught up in the "twins spool up faster than a single" thing. Cause it aint so if you size correctly.
Use a .96 a/r turbine on the single, and some .81's or even .68's on the twins.

03-09-2005, 08:23 PM
Yes the car will be on pump gas. Also keep in mind I'm in Colorado, our air is QUITE a bit thinner up at this alititude.

TurboLark, I was originally looking at a t70. to small for this application? What about a GT 42?

03-10-2005, 04:48 AM

Good reading.


03-10-2005, 07:38 AM
Thanks for the link Andrew, that was exactly the information I was looking for. I know the heads that I'm going to be using, and the amount of air they flow. Given I know this amount as well as the size of the engine, how would I go about compiling a flow chart for the engine. If I can come up with that I can choose the turbo I need pretty easily.

03-12-2005, 06:22 AM
Here's another awesome read