High or Low compression?
High or Low compression? Well i have had the heads and cam on for about 6 months and like everyone else im ready for more so heres the question
Im wanting to put in a 402 which will more than likely be from SLP since i can get a pretty good deal on it. So what im planning on doing is putting in the 402 with the head and cam setup i have now with a possibly bigger cam, then hopefully within a year putting a supercharger on it, possibly magna charger?? so if i go with a low compression engine will it be a dog until it gets some boost or will it out perform my setup i have now with just heads and cam.
Second idea was to get the 402 and put it on an engine stand and just wait till i can get the supercharger befor putting it in the car.
questions and opinions please does it sound like a plan?? should i just go all motor high compression etc. etc.
Im wanting to put in a 402 which will more than likely be from SLP since i can get a pretty good deal on it. So what im planning on doing is putting in the 402 with the head and cam setup i have now with a possibly bigger cam, then hopefully within a year putting a supercharger on it, possibly magna charger?? so if i go with a low compression engine will it be a dog until it gets some boost or will it out perform my setup i have now with just heads and cam.
Second idea was to get the 402 and put it on an engine stand and just wait till i can get the supercharger befor putting it in the car.
questions and opinions please does it sound like a plan?? should i just go all motor high compression etc. etc.
i think you hit the nail on the head on puttin the engine on the stand and waiting for the boost to come in when you have enough money, i would wait to get the boost, and do it all at once!! 
but man the sound of a hi compression block is a bitcin sound **drools**
but man the sound of a hi compression block is a bitcin sound **drools**
as stated by PSJ a ton of times.....if you drop 1 full point in compression you lose approximately 3% of hp....which is nothing,youll prolli not even notice the difference.Go low compression and get a custom spec cam for the mangnacharger and boost away!
I am going through the same questions right now. From what I'm hearing, the lower compression is not going to make a huge difference in performance. I was worried about down low performance, but everyone has told me that it's not an issue with a 347, so I'd imagine it's less of an issue on a 402.
Each point drop in compression will hurt you hp about 4%. Each extra lb of boost will increase you power 7% minus whatever power loss from driving the compressor, which isn't much. For every point drop in compression, you can increase several lbs of boost. So you can get several times 7% for each 4% that you lose. When you do the math, you have to go ahead and setup the motor for future boost.
i am still thinking of going with the high compression and a supercharger since i think a supercharger would be suitable for high compression. I dont know how long it will last but im planning on running about 6-8 psi.
Any ideas on hp/tq. numbers?? anyone with a similar setup have any numbers by the way thanks for the info.
Any ideas on hp/tq. numbers?? anyone with a similar setup have any numbers by the way thanks for the info.
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Bad thing about boost, no matter who you are....you WILL want more.
Like PSJ just said your quest for high compression will limit you. You can get away with it, but your tune will always have to be dead on.
If you lust for high compression, go N2O not FI.
J
Like PSJ just said your quest for high compression will limit you. You can get away with it, but your tune will always have to be dead on.
If you lust for high compression, go N2O not FI.
J
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aight so yall talked me into it low compression
but with low compression i might as well do a turbo setup since im going to buy headers anyways correct? plus the sound of a turbo.............
but with low compression i might as well do a turbo setup since im going to buy headers anyways correct? plus the sound of a turbo.............
I dropped my compression down to 9.3:1 and I can't tell a difference in the buttometer.
lower compression is better for supercharging and turbocharging. If you don't mind losing your a/c and p/s there are some nice turbo kits out there.
lower compression is better for supercharging and turbocharging. If you don't mind losing your a/c and p/s there are some nice turbo kits out there.
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Guys over at SilveradoSS.com run 9-10 psi of boost from the Radix with no issues on a 2.9 or 2.8 pulley, which is about as small as you can go and get max from the blower. And this is on an 6.0L LQ9, which I believe has 10:1 compression.
With a 402 you will be lucky to get 8 psi I think....trying to blow boost into all those cubes, you'll quickly run into the Magnacharger's spin limit (18K RPM's) before you'll have to deal with detonation due to excessive boost. I'd be very surprised if you saw anywhere near 9 psi on a Magnacharged 402.
So, I think a Magnacharged, high-compression 402 is certainly do-able. Can you get more boost with a turbo? Certainly. But I bet you wouldn't be able to match the low-end power and torque of the blown combo.
With a 402 you will be lucky to get 8 psi I think....trying to blow boost into all those cubes, you'll quickly run into the Magnacharger's spin limit (18K RPM's) before you'll have to deal with detonation due to excessive boost. I'd be very surprised if you saw anywhere near 9 psi on a Magnacharged 402.
So, I think a Magnacharged, high-compression 402 is certainly do-able. Can you get more boost with a turbo? Certainly. But I bet you wouldn't be able to match the low-end power and torque of the blown combo.
Originally Posted by 02_CETA_ws6
... since im going to buy headers anyways correct? .............
Originally Posted by ddnspider
wrong,a turbo setup usually uses custom headers to a crossover pipe of some sort,therefore getting longtubes for instance is a waste of money.
nevermind the magnacharger question i just seen the forum on how it was to big to fit under the hood/dash
How about the phamspeed budget kit??
sry for all the questions i just wanna plan everything out befor i do it.
How about the phamspeed budget kit??
sry for all the questions i just wanna plan everything out befor i do it.
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Joined: Mar 2003
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From: La Porte, TX
I'm not too sure if Phamspeed is still producing kits...Perhaps somebody can verify. I think they got in a little bit over their heads, and had to stop taking orders until they could catch up. Does anyone have more info?