[Shaolin Crane]

Ok ive been doing alot of research regarding what supercharger to run how much horsepower and what boost and compression ratios i want to run my goal is 800-850rwhp so according to static compression ratio, effective compression ratio relative to boost and a moderate engine compression for an effective street driven beast am i to assume my math so far is correct...
Effective compression for a moderate to heavily modded street motor is 18:1
assuming i have a 347 that makes 430rwhp (mods to do so are not important at this time) with 9.5:1 static compression(18.5 effective compression) will make the 8XXrwhp at 14psi of boost with 91 octane an a suitable aftercooler? Any more knowledge on the subject will greatly help me

[94cobra69ss396]

I really doubt you will be able to get 800+rwhp with a 347 on pump gas, even with an aftercooler. You also will not double you rwhp at 14 psi. You are going to have to either run more boost or make more power N/A to reach 800rwhp.

[enkeivette]

We had a big thread debate on this already. Technically 14.7 lbs will double your hp, but that doesn't include loss. Like added heat or the 20%? loss from the motor having to drive the blower. If you want 800hp, calculate what you need for at least 1,000.

Better idea if you want to run pump gas, something I decided was a must for me, call the blower company, give them your specs and ask them how much boost you can run on 91. Then ask what pulley you'll need to get close to that much boost.

[enkeivette]

PS. My H&C 383 is supposed to be good for 500hp with high compression, it's only 9:1 so it would never make that NA. With 13lbs of boost I'm only hoping for 600-700 flywheel hp intercooled.

[Shaolin Crane]

ok but my math was correct though right? i didnt mean this as set in stone, just trying to further my understanding when it comes to boost my goal was already to shoot for the 1000hp mark and if i walked away with 800hp i would be happy, my blower choice was already the F1c as it has he stepped ratio that would spool at a lower RPM than a normal F1r

[Vettezuki]

Originally Posted by Shaolin Crane

. . . assuming i have a 347 that makes 430rwhp (mods to do so are not important at this time) with 9.5:1 static compression . .

I've never heard of an NA 347 with 9.5:1 CR making 430WHP on 91. My 346 LSx made 432 WHP in the vette it came out of. It's north of 11:1 and needs about 93 octane. Good for the spray, not for boost.

(18.5 effective compression) will make the 8XXrwhp at 14psi of boost with 91 octane an a suitable aftercooler? Any more knowledge on the subject will greatly help me

In a vacuum (i.e., pure theory, no modifying factors, yeah approximately). HOWEVER, it never works that way and there are a lot of reasons, maybe enkei will find the post where we harassed him. I think a boosted 347 making 800WHP on pump gas is a Unicorn. I've never heard of one and can't imagine the combo necessary, save for much lower static compression and higher turbo (not SC) boost. It wouldn't be a friendly street driver though, it'd have big lag that would come out of no where and kick you in the face, more like a drag car you'd spool and launch.

Ron whattaya think?

[Shaolin Crane]

Originally Posted by Vettezuki

I've never heard of an NA 347 with 9.5:1 CR making 430WHP on 91. My 346 LSx made 432 WHP in the vette it came out of. It's north of 11:1 and needs about 93 octane. Good for the spray, not for boost.



In a vacuum (i.e., pure theory, no modifying factors, yeah approximately). HOWEVER, it never works that way and there are a lot of reasons, maybe enkei will find the post where we harassed him. I think a boosted 347 making 800WHP on pump gas is a Unicorn. I've never heard of one and can't imagine the combo necessary, save for much lower static compression and higher turbo (not SC) boost. It wouldn't be a friendly street driver though, it'd have big lag that would come out of no where and kick you in the face, more like a drag car you'd spool and launch.

Ron whattaya think?

Hmmm ok, well as long as my understanding of the equation is there i can start focusing on learning the variables, but i have seen many 800rwhp motors on pump gas over at stangnet, but if need be i can always run race gas or avgas

[Vettezuki]

Originally Posted by Shaolin Crane

. . but i have seen many 800rwhp motors on pump gas over at stangnet. . .

I'd be curious to know all their variables and see their sheets. Lower static CR, more than one atmosphere of boost and heavily intercooled, on a pump gas 347, maybe.

I'd also be hesitant to call it an equation in anything other than an idealized sense. Details will always revise real output DOWN.

And finally, I've never been in an 800WHP car. I've been in enkei's Vette which is probably well into the 500s . . . it's ridiculous. At 800WHP, you're going to have to make everything on the car heavy duty and carefully dialed in or it'll be a death trap.

Keep us posted.

[Shaolin Crane]

Originally Posted by Vettezuki

I'd be curious to know all their variables and see their sheets. Lower static CR, more than one atmosphere of boost and heavily intercooled, on a pump gas 347, maybe.

I'd also be hesitant to call it an equation in anything other than an idealized sense. Details will always revise real output DOWN.

And finally, I've never been in an 800WHP car. I've been in enkei's Vette which is probably well into the 500s . . . it's ridiculous. At 800WHP, you're going to have to make everything on the car heavy duty and carefully dialed in or it'll be a death trap.

Keep us posted.

sorry i should have stated this will not be a traditional hydraulic roller cam engine, this will be a full mechanical roller cam, linked lifter, 0oz imbalance high rpm engine

everything on the car is heavy duty, full MM catalog, built 8.8, 10 point cage (not installed yet) and next weekend i will be gauging the bumpsteer, cornerweighting the car and carefully balancing everything to make sure the car is as predictable as possible

[94cobra69ss396]

You're building this engine for your road racing Mustang, correct? Are you going to be racing it in a series or is this just for fun? Right now you have a pretty much stock 302 that probably makes about 200rwhp or less. Even with a mildly built 347 with 9:1 compression and 10psi that will run on pump gas you should be able to make a reliable 450-500rwhp. Trust me when I say that even with that you are going to be more than happy with the available power. The 275 rear tires you have now will have a hard time holding that much power when on the throttle coming out of a corner. This is what Eric has planned for his fox body only with a 331.

Back when I decided to rebuild my 302 and add the Vortech S-trim I had my car dyno'd to see where it was at for a base line. It made 254rwhp. The only things I changed besides adding the S-trim and it's supporting mods (injectors, fuel pump, MAF, etc.) was a set of AFR 165 heads and an E303 cam. I figure if I were to have dyno'd the car after installing just those I probably would have made closer to 300rwhp. As my car sits now with 12psi it made 436rwhp on 91 and 471rwhp on VP Street Blaze 100. Now granted I'm not running an aftercooler so there is still another 50rwhp or so I could be making on pump gas but that is still far from double the power output of the N/A combo.