texasTA

Is this okay for everyday driving? Am I going to be leaving a bunch of power on the table by not incresing the compression to say 11.0:1 or even 11.5:1? This is going to be a nitrous solid roller motor.

Thanks

Mystic97Z

i'm sticking to exactly the same thing for my 355 hydrallic engine...
people say they run 11.5:1 but all machine shops said, even with reverse flow cooling heads u still wanna stay in the 10's...
i'd say thats perfect, can't get much better than stock!

rskrause

Depends on the cam, all else being equal.

Rich

NewbieWar

i think the lt4 was 11.1 if i remember correctly

texasTA

Elaborate please...
The cam in my car is a custom ground Cam Motion solid roller camshaft. The specs of the cam are = 245.7/251.1, .654/.606 installed at a 111.8 Lobe seperation. The Duration is at .05

JustNO

IMHO its not a daily drive cam..

texasTA

Yeah, I plan on driving it around some, but mainly to local car shows and events. It should still do fine for street/strip duty, even with that cam. Jordon used that very same cam grind and loved how it acted on the street.

WS Sick

I'm running that compression in my 383 with the GM 847 cam and have never experienced ping on 91 octane gas.

Deenasty

it all depends on your static compression. Dynamic compression is not all that important. My 383 is running 10.5:1 compression, and I wish I would of went with 11.5, which would of netted me a rough 8.5 static compression, which you want to stay under 9.0 for pump gas.

here is a calculator:

http://www.rbracing-rsr.com/compstaticcalc.html

atljar

That cam will be very driveable with SR ramps + cubes.

GetaZforgetGT

You have Static and Dynamic Compression backwards.

Dynamic is the important one...you have the right concept but switched the syntax.
Dynamic must be under 9.0 for pump gas.

95Bird

I'm running 12.5 CR and race my car on pump gas most of the time. My cam is bigger than the one you listed though. No pinging and the car runs great on it. In fact..my 10.7 pass was on 93 pump gas.

94zgreenmachine

My machine shop said the same but I heard different from Lloyd and Brett. Dynamic compression plays a role along with cam selection. I choose a custom grind based on my piston cc and deck height. I'll have a tight quench of .036 so we went from there. Lloyd didn't even want to do a cam selection till I had deck height and piston cc. I was told it will be close to the GM847 but... with a lil more lift

Shawn 97 Z28 M6

All else being equal.. I've heard that each point of compression you come up is worth ~10hp... Personally I'd think it to be more, since any blown motor application (i.e. 9.0:1) I've seen dyno about 40rwhp less than it probably would if it were up around 11:1 . Then again.. Who am I to talk? My car only makes 385rwhp and is 12.2:1 .. lol. I suck!

next question?

Black95Form

Wow, self esteem issues Mr Saladbar.

TexasTA,
It really depends on the complete setup like Rich said. Its all about the dynamic compression, not the static. I am running a 12 to 1 using a solid roller thats 254/262 on a 111 LSA. It nets me a dynamic of about 8.5 to 1. BTW, can we hook up this week.

Michael