jman123

Members,

I have a couple of questions concerning type of head unit and amount of boost that I can you on my 87 vette. I recently completed a complete rebuild of the drive train, suspension and engine late last year. After spending sometime reading the articles in this forum, I am considering a ATI supercharger as a added power addition. below is the motor configuration.

Given the highr compression can the DS1 run at 7 to 8 psi? or is the p600b a better choice with the 8 psi pulleys? Is belt slippage a real issue at lower boost presures? any insights with S/C higher compression motors would appreciated
P.S overall goal most safe hp possible while retaining good streetabilty

Thanks all
4 bolt main with ARP main cap bolts
forged Lunati Crank
4340 Hbeam forged rods with ARP rod bolts
Speedpro forged pistons 10.5 to 1 flat top
Forged rings
ARP head Studs
Trick flow twisted wedge dual spring heads
trick flow roller lifters 1:5
Crane Cams roller Cam .509/.528 lift 222/230 duration
TPIS miniram II
BBK 58mm TB
30lbs FSVO injectors
255gph fuel pump
Ed Wright Chip
1 3/4" hooker headers into 3 in cat and 3 in outlet
built 700r4 trans 2800 stall - 3.23 rearend

tjwong

With your compression ratio as high as it is, in my opinion no more than 6 PSI or 8 PSI intercooled. 6 is by far safest. However if you haven't built the engine yet, then drop the compression to 8 or 8.5:1 and then you can safely put 12 PSI on her on pump gas.

jman123

Tjwong,

Thanks for the reply. The motor is built and in the car with 300 miles on it. If 8 psi intercooled is the max, which unit would work better p600b or the DS-1? if I move to a 3.54 or 3.73 rear end will that have any effect on the max boost? Is 30lb injectors ok at 8psi?

jerkyboy

:lurk:
I am watching this thread too as I have a similar engine set up except I'm at 10:1.

SurfnSun

A gear change won't affect the boost.

AKS Racing

I ran 8 psi for several years with 11.2:1 scr. The key is in the tuning. If you are spot on (w/out detonation), you can probably run for some time in that mode. If you are running the factory ECM (burning chips), I think it will be quite tough to do it long term. I have tried that as well.

As for the D-1 vs P-600B, go with the D-1 and turn the blower slower (very easy to run underdrive pulley on the crank, or step up to a larger crank pulley to limit boost). Then if you do lower the compression, you will have a head unit that will handle the larger requirements.

Glad to see others playing with the early C-4s (L-98s).

Best of Luck,
Aaron

tjwong

For your car personally I would recommend the P-1SC or the P-1SC-1 both are self contained meaning that it contains its own oil resorvoir. The P600B is also self contained. While others may recommend the D1 it is a much larger blower that you would have to underdrive. And unless you are planning on upgrading the engine to use the D1 to its full potential then there is no sense in going to the larger blower. Plus you have to run a pressure fed oil line to the blower which isn't a big deal, but running the drain line to the oil pan is.

Both the P-1SC and the SC-1 gives you a bit more room to grow if you want it. Plus it will offer a bit more efficiency over the 600b because it won't have to spin as fast to make the same boost levels. If you have any questions call Procharger and ask for Dorian, he is very knowledgable of their products and I am sure he would agree with what I told you about effieciencies.

I would use 42lb injectors and have a custom chip or tuning to your PCM. Run a single large in tank pump with a Kenne Bell Boost a Pump that is boost activated. I recommend a Walbro GSM 340 pump, and when used along with a BAP it will provide more than adequate fuel for that boost level. When the BAP activates it overdrives the pump by 150% which effectively boosts flow levels 150% as well. With the proper tuning you won't have to use a band aid such as a FMU in the fuel return system. Remember the key to power and longevity on a blown engine is the prom or PCM tuning.

Gears won't affect your boost levels. Only engine RPM has an effect on boost with these centrifugal blowers.


[Modified by tjwong, 10:17 PM 2/19/2004]

AKS Racing

The P-600B is not self contained. It will require an oil feed and return. The P-1SC series are self-contained.

Aaron

tjwong

Aaron you are right my mistake! :) For some reason I thought they were.

ZD1

Get rid of the Ed Wright chip and have prof tuned!!!!!!!!!! I've seen his spark tables

GRX

I was going to run 6-8 psi on my stock old motor but got greedy (and smart) and embarked on my quest of 10-12 psi see below.... :banghead: