compression ratio? good for boost?

[cplonner]

How do i find out my compression ratio for my newly built engine? Its a 350 with vortec heads and flat top pistons. I was told by the mechanic that it has a 10:1 or 10.5:1 compression ratio but this guy was a flake. How can i be sure? I was wondering if this setup is any good for putting an intercooled supercharger on it. I was looking at a chart from ati and it said this compression is good for 8-11 lbs of boost when intercooled. my setup- Comp cam- 474 lift int/exh dur. 210 int 214 exh Vortec heads (cast iron) hypertuetic flat top pistons long tube runners and big mouth base intake hooker headers (powder coated) I figure i can plan for the future when i want more power and put some pressure in their but im still learning about it. Any advice would be great.

[lcvette]

you need the part number of the pistons used to determine what the volume is of the dome, measured in cc's, then take the compressed thickness of the head gasket used, the volume of the combustion chamber of the cylinder heads, find out how much material was removed if they have been milled, [find out how much of the deck was cut during the machine work, and then you have all the information you need to accurately determine your compression ratio. you can plug in the infor here:

http://www.csgnetwork.com/compcalc.html

have fun with it

[cplonner]

does anyone know if this is a good canidate for intercooled boost if the com ratio is 10:1? I know thats high but 6 lbs gets you some good power doesnt it?

[redbullapril23]

with only 6lbs you might as well just use nitrous.. because you can get more power. for less $ too.

usually ud want like 9.5 or less.. i belive. at least thats what i see people doing round here.

to jsut run 6lbs and spend about 6k...
hopefully others will chime in.

[Mo_Bandy]

cplonner,

Many are running 6-8 pounds of boost with 10- 10.5 compression ratio. making probably close to 400 horse at the crank. The best setup is 9.0 or there abouts with forged pistons rods and crank.

If you are happy with that... the down side is we all get the hunger for more power more speed. In doing that you risk cracking your pistons as the hypertuetic pistons will not handle a lot of detonation. You are certainly on the right track about intercooling. There are a number of ways of using either air -air as Procrharger does or I chose to go water methanol injection. Which heps in terms of running a little more boost an is very good at controling detonation and you can run with a bit less fuel which would normally be used for cooling.

I shudder to think how much moneyit has cost me to get the car where I want it... I prbably could have bought a second C4. Saying this meaning supercharging is not cheap... you get what you pay for... and if you break something it will cost more. Also running more power there are internal parts that need to be changed to handle the added boost and power. as I mentioned above, forged pistons rods, and crank...

If you are planning on just "beating around" and not seriously racing the car you would be fine... but you would need to invest in logging software perhaps have to get the ECM programmed etc etc. with a new supercharging system it would run you about 6K plus the installation with other parts and pieces an easy additional 2K.

If that is not in your budget, then as posed above you should perhaps consider a NOS setup...

Hopefully this helps answer your questions...

Mo

[drochau]

Did the flake mechanic build the engine too?
If I had to do it all over again on an unforged engine, I would have definently elected for nitrous. In fact, even with the supercharger, I have elected to add nitrous as opposed to going cog drive/F1 head unit. Have fun!

[Mo_Bandy]

Originally Posted by drochau

Did the flake mechanic build the engine too?

Mo

[cplonner]

Yes sadly to say "the flake" did build the engine and i had to go back and tighten some vacuum lines adn the distributor.
He also charged me for some little things that were not on the engine. Its a long story and he got the short end of the stick in a matter of speaking.

Nitrous sounds like a good path to go. My next engine i will problalby set up for boost, ill be making more money then. For this one a nitrous kit sounds like a good idea. just a 100 shot sounds nice. Now is it difficult to install if you have decent mechanical ability?

[drochau]

Nitrous? not at all. Single fogger should be plenty for a 100 shot. Wet would be best. If you can wire a car stereo, you have plenty of mechanical ability for the job.

[cplonner]

sweet. after a new tranny im gonna look at the different kits.