How big can I go
Whats the biggest turbo you can install on a beta engine without changing the internals? I dont want to mess with new cylinders or any of that. Just fuel delivery and ignition.
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Joined: Mar 2006
Posts: 12,515
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From: Lacey, WA
Vehicle: Two Accents, Mini, Miata, Van, Outback, and a ZX-6
You could run as big of a turbo as you want as long as you limit it to about 12 PSI max on stock internals. To make 12 PSI work you'll need a really good tune. 8 PSI is pretty safe with a decent tune. That's assuming you have PROPER fueling and ignition control taken care of.
12 PSI has an effective compression ratio of 18.16:1
8 PSI has an effective compression ratio of 15.44:1
((boost psi / 14.7) + 1) x motor compression = effective compression
As far as deciding the turbo goes I think it's an error to think about it from the angle of how big of a turbo can you run. Turbos have a lot of different characteristics that you should look at in deciding which is right for your application. What are you looking to do with the car? A fun daily driver? A drag car? A road course car? A dyno queen? A show car?
12 PSI has an effective compression ratio of 18.16:1
8 PSI has an effective compression ratio of 15.44:1
((boost psi / 14.7) + 1) x motor compression = effective compression
As far as deciding the turbo goes I think it's an error to think about it from the angle of how big of a turbo can you run. Turbos have a lot of different characteristics that you should look at in deciding which is right for your application. What are you looking to do with the car? A fun daily driver? A drag car? A road course car? A dyno queen? A show car?


