94Cbra

Sorry about all the questions but I've decided to scrap the supercharger idea and go all motor with some N20 on the side. I dont get on here and ask questions until I just cant find the answer. Ive researched for hours and cant find this crap. Anyways, first I wanna know: What is the highest compression ratio I can go with pump gas (93 Octane). What is a good octane booster and how much does it cost? My next question is how agressive are these camshafts (Pro-Mustang Hydraulic Rollers)
_____Valve Lift - Duration - Duration @.050 - Lobe
Ive typed it as Intake/Exhaust
#1.) .539 .565 - 272 282 - 225 234 - 112
#2.) .493 .510 - 279 289 - 212 222 - 112
#3.) .510 .534 - 289 299 - 222 232 - 112
#4.) .544 .573 - 284 294 - 238 248 - 112

Which is most/least agressive
I just wanna make sure I know exactly whats going on when I put this Kit on my car. Dont wanna fack anything up over stupid stuff.

roundman

you probably can't exceed 10.0:1 compression using pump gas but that isn't the only factor that determines the peak cylinder pressure that will let you run pump gas, the cam, heads, combustion chamber size, piston top shape and other things also have a lot to do with whether pump gas is feasible to use. of the cams listed, #4 is the most agressive since the lift and duration figures are the highest. bear in mind that you can't run this much lift with larger than stock valves without having bigger valve reliefs cut into the pistons. 2.02" intakes and about .498 lift is a close combination that still needs to have the piston to valve clearance checked to make sure there is enough to keep the piston from hitting the valves.

vfast

why would you ever build a street engine that couldn't run on 93?...it so easy to make a very fast street engine run on 93..none of those cam are out of line for a street car. you get into trouble on a roller or non-roller when your centerline is in the 106-108 range and with these cams comes with big over lap....you could go with the 573-595 cam that crane has out and use flat tops or a small reverse dome with some 2.05 intake valves

tinman

What sort of gas you can run is sort of determined by cylinder pressure. #4 cam would be the most aggressive all right but what sort of overlap do the valves have?
Also, if you are running at a higher altitude with less air you can cheat the octane a little bit.
Here in Arizona where there is NO air we can get away with as much as 10 compression on a carbed car on 93 gas.

roundman

how do y'all manage to breathe out there with "no air"? LOL

vfast

?????

Moosetang

I'm intrested in the octane booster thing too. What is the cheapest?
Cause that **** proably adds up.

roundman

At about $7 a bottle I should say so! LOL and it's not a real cure for the problem either!

94Cbra

Vfast, I AM building a street machine to run on 93... Is that #4 cam gonna lope very hard? Im getting all this but im still learning so thanks for everything.

94Cbra

As for the cam shafts, I was wondering which was most agressive because I can pick one for my stroker kit. Hell, those guys a CHP are figuring all that crap out for me, they say "Which one" and I point.