I'm aware of the fact that a stock LT1 setup ( 10.5:1 SCR) cannot run high boost levels for long.
I was wondering though if there are people that run medium-high SCR ratios (10:1 - 10.5:1) with a rebuild engine that contains forged rods, pistons and proper hardware (ARP bolts and studs) ???

I'm also aware that most people who run a SC will drop the CR while rebuilding it but i can also imagine people rebuiling an engine and then decide to add a SC eventhough the CR isn't ideal.

 

im thinking about having a short block built. forged bottom end and leaving the pistons the stock flat tops and using 62cc heads to drop the cr. that way if i ever need to remove the SC, i can replace the heads to get my CR back up instead of rebuilding the bottom.....

just a thought for you.....

 

I hear ya, but that's not an option for me now as i have my engine nearly finished and i'm quite happy with the high CR specs for N/A performance.
BUT knowing myself i might get used to the performance really easy and i was thinking of using some form of FI to get the extra performance i could be lacking.
I'm NOT aiming for 800Hp but i would be very happy with about 550-600 Hp (at the flywheel) and proportional torque.

Looked into bringing the SCR down to about 9:1 using a 1.20 thick head gasket made of Multi layer steel but people here advised me not to do so.
Therefore i was thinking of using a thicker gasket that's still within limits yet bringing the SCR down to about 10:1 which is less than stock so the engine should be able to take some mild boost (6 psi should be more than doable).
Since i have all forged internals i figured i could run 8-10 psi using 93 octane premium.

I was wondering if some people have done this before or have experience in this field.

 

You ought to look into water/methonal injection if you
want to run a high CR w/boost. Just do a Google search,
there is plenty of info out there.

Emil:93Z,383,Vortech,NOS

 

www.snowperformance.net

good meth kit. adds power too....

 

I had good luck running the alkycontrol.com progressive kit - 14psi with 10:1 compression, using the cheap 99 cent wiper fluid.

 

Now that's pretty impressive !!
That's the experience i was looking for and love to hear about.
Was it rigged to only inject fluid at a certain rpm/boost value ?

 

I'm running about 10.6:1 with 7lbs of boost and a water injection system from Kenndy's Dyno Tune. All forged internals. We had to bring the timing down to 22 degrees total advance to eliminate the knock retard. We are going to play with the water/meth injection a little more to see if we can make any more improvement. There were some guys that posted on this thread yesterday that deal with turbos and high compression but it appears that their posts have been removed. Does anyone remember who they were?

 

I've seen those posts David, thank for pointing it out.
Ok, so it looks like high CR with boost can go along with some boost
How is your car behaving ? How is the ride compared to the configuration before you installed the SC ?

 

My kit is setup to activate at 3psi (which is the stock preset)

 

NA it was making 365rwhp/ 388rwtq. With 7lbs of boost it was making 443rwhp/ 513rwtq--we still had 8 degrees of knock retard. It is at the dyno right now being tuned further, so we will see what happens. To show how valuable and critical dyno tuning is, when we went from 26 degrees total advance to 24, we picked up 20 rwhp immediately. That was when we recorded the 443.

 

Sounding good ! Well i think this answers my question.
It's good to see that even with thestock like CR some boost can be used to make that extra power without going beserk.
Amazing that the ignition timing makes that much of a difference (horsepower wise).
I assume you are still running the OEM computer with a proper reprogramming ?

 

i am running he stock compresion with an ati procharger p600b with intercooler with no problems yet. keeping fingers crosed lol. my whole moter is not forged just the pistions. also i am running 8 psi.

Shane

 

Well reading that you have Eagle internals i think you have more than just forged pistons .....
From what i know those items from eagle are usually forged.

 

no i just got the upgraded replacements they are the best the make other than forged my farther and i built the moter last summer and bought everything from summit. i kind of wish i did forged everything but it all done so i will just have to live with it for know.

Shane