[Diy_efi] Re: [Diy_efi]

[Kenny]

Quoting Bruce <nacelp at bright.net>:

> 
> At what cost?.
> For a 8 PSI application, I really doubt if you
> could tell from the drivers
> seat.  

As in, you wouldn't be able to tell the difference 
between 1 or 2 turbos? If that's what you mean then for 
sure. Lag comes into play when you're running a turbo 
with a large compressor trim because you want 
efficiency at high boost, so you compromise. No 
compromise needs to be made at 8psi. You can get a tiny 
turbo to do that (like a mitsu TDo5-12b or 13c, or even 
a little T04). You can size a small turbo because you 
don't need it to do much work. 2 turbos is silly for 
8psi and high compression. twin turbos are used 
primarily for enhanced drivability in higher boost, 
lower compression cars- and even then they are usuallu 
staged electronically. Once people get serious with 
boost they swap to a single unit. Absolutely no reason 
to run 2 turbos for 8psi. Why do you need all that hair 
drier? A single well sized single turbo with the stock 
compression ratio will give a quick, almost lagless 
spool up. Sizing is key though. My car is a turbo 2.1L 
with a 60 trim T3 and at less than 12 psi it's a wee 
bit big. Ie throttle on just before and apex-> lag-> 
boost-> power oversteer that is a little unpredictable 
in the wet. I'm currently turboing a 2.3L volvo and 
keeping it's stock 10.5:1 compression ratio (well, 
it'll be a touch less after the headwork). With a small 
turbo and high cr it will have tremendous bottom end. 
It will likely only see 6 psi. But if I can get the NA 
HP up to nearly 200, that's almost 300hp. Sorry for the 
rabbit trail. Bottom line, anybody who things twin 
turbos is necessary or helpful for 8psi is likely 
incapable of such a project. The exptra expense and 
complexity of running twins would yeild little 
difference. Go single and spend the money you would 
have spent on the second turbo on a valve job and a cam 
and you'll KILL the twin turbo.  
  
-Kenny
AKA Captain Bondo

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