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High compression 4v + blower =

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#21 ·
I have a Sean Hyland book that says that with a centrifugal supercharger you should keep the compression ratio on the high side, 10:1 range, so the car isn't a dog on the bottom end.
 
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#22 ·
^ I would only take a very little bit of that book as knowledge.

He is kinda right...but 10:1 with boost. Better be running great gas all the time if you want to push it.

Like I said. Stay in the 9 no lower, and no higher than 9.5ish...It won't be a dog at that comp. most mustangs came stock with 9.6-9.8 anyway.
 
#23 ·
it has been proven that raising boost with out detonation makes more power than raising compression and reducing boost. with e85 you can have the best of both worlds but if the op plans on running 91 octane i would stay around the mid 9.5's and run more boost.
 
#24 ·
Bullitt5566 said:
I have a Sean Hyland book that says that with a centrifugal supercharger you should keep the compression ratio on the high side, 10:1 range, so the car isn't a dog on the bottom end.
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That would be true at lower boost levels and running good gas. It would be a would be good for 10 psi or less. After that the higher CR would be more of a liabilty. If you're running 15+ psi it dosen't run like a dog at lower RPM's and still pulls like s freight train up top. Best of both worlds. If you want to make big safe numbers go low CR it will always have more potentail.

When Sean Hyland was popular very few people were making 600+ with modular engines. I always thought Sean Hyland was over priced and over rated. That's why they have almost fell off the map and once they were the biggest.

NeverEnuff said:
^ I would only take a very little bit of that book as knowledge.

He is kinda right...but 10:1 with boost. Better be running great gas all the time if you want to push it.

Like I said. Stay in the 9 no lower, and no higher than 9.5ish...It won't be a dog at that comp. most mustangs came stock with 9.6-9.8 anyway.
Click to expand...
+1. The 99 to mid 01 GT windsors had only 9.0:1 stock.
 
#26 ·
I would like to run about 8psi from a centri on my set up and stay around 500-550 all the time. I think I could get away with it if I used a intercooled setup along with my meth kit. Would be interesting.
 
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Discussion starter · #28 ·
I would have gone big bore if I didnt have a Teksid block. Cant go as big on an aluminum block. The reason I was gonna go with the 4.75 stroker was because I was planning on buying a completely forged setup from MMR and the 4.75 stroker for some reason is even cheaper than the 4.6 for the same power rating (on sale). I figured I'd save a little money and get a little extra power too. NeverEnuff, do you have a link or price on your crank? And does it need any machine work?
 
#31 ·
it kinda really depends on what type of boost..since they are different... on my cobra my compression is about that and i run 21lb on pump..but this is with a twin screw.. with like a 76mm turbo prob limited to about 17lbs or so.. centri blower could do 20 since is on a rpm by boost type of deal...with high 10:5 compression on race gas you can run 25+ lbs..so it just all depends...my 2v engine is 10:1 and with my 80mm on pump i will be able to run prob around 15lbs on pump which is just fine with me because that still will make some nasty power... but on race gas i can throw whatever i can at it that my stock ignition can handle lol..
 
#33 ·
boost is a measure of restriction so i never seen a p1 do 20lbs on a 4v(never seen a p1 do 20lbs on anything really besides a race car thats over spinning it without an intercooler)....so i cant answer that for you lol..
 
#34 ·
if i where you i would start with a d1 at least that way you arent killing the blower and you will less likely have problems from trying to spin it so hard... i know mach 1s with d1's and 15lbs makeing around 550ish or so easy..
 
Discussion starter · #35 ·
Well here's a video of one putting down 637rwhp on a P1sc at 18psi.

637 rwhp 03 Cobra Vert

Mods:
Procharger P1sc @ 18psi
Bassani Catted X-Pipe
Bassani Catt-Back
60# Inj
Steeda Full Length Sub-Frame Connector's
Steeda Cold Air Intake
Steeda Strut Tower Brace
GordsFord Heat Exchanger with Fans
KenneBell Boost-A-Pump
DiabloSport MAFia
DiabloSport Predator
Custom Tune by Brown Bros Ford
 
#37 ·
#38 ·
codycat91 said:
I would have gone big bore if I didnt have a Teksid block. Cant go as big on an aluminum block. The reason I was gonna go with the 4.75 stroker was because I was planning on buying a completely forged setup from MMR and the 4.75 stroker for some reason is even cheaper than the 4.6 for the same power rating (on sale). I figured I'd save a little money and get a little extra power too. NeverEnuff, do you have a link or price on your crank? And does it need any machine work?
Click to expand...
WHy can't you big bore a teksid? Those are the ones you want to. Along with WAPs and explorers. Alum blocks are big bore brothers.

Whatever you think its worth to you. Ill give it to you plus shipping. Not looking to make money on it brother.
 
#40 ·
Copycat, you do not know how encouraging that post was. I already have a P1SC. When I get a forged block I'm going to want to get a little better performance out of it. Most of the Vortech guys say its not possible. Thank you.

Now, all I've got to figure out is the compression ratio of the new motor.
 
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NeverEnuff
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