<VV> Re: Turbo Boost

[Jim Burkhard]

If the engine has never been fired, I'd start out with boost 
really limited until you break it in and shake everything 
down.  You want to make sure it is knock free at o psi 
before 5 psi and 5 psi before 10 psi.  If it's spark knock 
happy, damage can occur very quickly at high levels of boost.

You should strongly consider a Safeguard ignition system 
(from Ray Sedman @ http://www.american-pi.com/) as a smart 
(it learns) last defense against knock (and it's got a host 
of other nice features). Ray has also built many turbo 
engines and can give you a good idea about boost limits. It 
depends on how dicey you want to be, but maybe 15 psig on 
TRW forged pistons. Many people go higher, but you live on 
the edge a bit & (I think) Ray would recommend custom forged 
pistons beyond there (ask him).

Jim Burkhard

Bucketboss at aol.com wrote:
> I have a LM Turbo 180 that I will be running this spring and I have a  
> question for the bent parts and melted pieces guys out there.  This engine has 140 
> heads cut to 8.5:1 , TB 20 cam, dual springs, balanced,  2206 TRW's, Weber 40mm 
> carb, and a wastegate. It has yet to be  fired. My question is this. What WG  
> spring should I limit my fun to?  6-8-10 psi or can I go higher and to what 
> limit without SERIOUSLY limiting  durability? I plan H20 injection. Has anybody 
> tried to use a MSD  ignition with the boost controller for better control? 
>  
> Thanks, I would appreciate any insight.
>  
> Dave Fierek