2006GT500

Have a D1SC or a Kenne bell 2.4? And why? I'm thinking of selling my D1 in order to buy another members 2.4, just haven't figured out if thats what I want to do or not. I know what kind of power I can make on my D1 and don't think I can make it on a 2.4. However, instant boost would be fun too. Give me your opinions and why you feel that way.

PACETTR

DD = KB
Track Car = D1
Good luck either way!

anthony05gt

I agree. D1 for track...KB for street. If you don't like noise go KB too.

2006GT500

I made 523rwhp and 493rwtq with my current set up and there aren't many guys making that power on a KB however my power is way up top is there anything to make the power come on sooner in the rpms.

70MACH1OWNER

I have never owned a centrifugal. I have had a KenneBell on a 96 Cobra. All I can say is when you are driving around normally every day you are not at WOT. Peak HP does not make for a fun daily driver. Twinscrews are the only way you want to leave a stoplight everytime. And 0-50 you will never beat a twinscrew.
Scott

don_w

Yea, what he said.

In fact, I'll add that "peak HP" is pretty much a useless number in general (even for a track car). What matters is what kind of torque and HP numbers you're getting throughout the entire RPM range. Unless you're at Bonneville shooting for a sustained top speed record, "peak" HP rarely comes into play at all.

TillmanSpeed

Building the bottom end up will take care of spool time, and get that low end up to par!

anthony05gt

Building the bottom end up? To what, high compression? Exactly what you don't want with a blower.

tom281

Having driven several S197s with TS and owning one with a centri, for me I'd stay with the centri. Both are great; both have pros and cons. Depends on what you want to do with the car...... evaluate that first, and then make up your mind.

Willie

I've read a lot on this forum about how centrifugals don't have any low-end...... I've owned three centrifugals, from a Paxton to a D1SC and also an F1. I've discovered that they are low to build boost ONLY when it is pullied for low boost applications, i.e. 10-psig....

Given the crank and blower pulley diameters, I can calculate engine rpm at blower redline and once I've installed the correct pullies to "match" the blower to the engine redline, low end boost has NEVER been an issue. In fact, my last setup on my IROC-Z (prior to going to twin turbos) was an F1 with twin air-to-air intercoolers. The car had 3.73's with a 3.06 first gear ratioed 700R4 and a 3,500 rpm stall 5-disc Vigilante converter. Even with burnouts on E/T Streets, launching at 1,000 rpms (yes, barely off idle), I'd hit boost almost instantaneously and would have a tendency of going sideways. In my prior years with pullies making less boost, I never had this problem.

Centrifugals with air-to-air intercoolers are my design by choice and once it's matched to the car's gearing, there's no better way to go -- low-end boost and high-end power.....

2006GT500

So Willie how do I go about getting everything lined up to make low end boost?

Willie

So Willie how do I go about getting everything lined up to make low end boost?

Before I answer, I need to know a couple of things:

1) What diameter pullies do you now have?
2) How much boost are you making and at what rpm?
3) What is your best 1/4-mile ET and mph?
4) Auto or manual?

Funny how you should be asking a Chevy guy !!

Willie

2006GT500

1) I have the biggest of the 3 that came with my kit on
2) 11 psi at 5500rpm
3) N/A
4) manual

Willie

In order to calculate blower rpms, I need to know the pulley diameter of both the crank and blower pullies.....

FYI, I used to have a D1SC too with both a 12-rib and cog pulley system. I experimented a LOT with different pullies. This spreadsheet is one of many I used to compile data to best select pullies on my IROC-Z when I had the D1SC many years ago.

Willie

Faber

I was pondering the boost curve for centrifugals and thinking "if you had it pullied for big boost early on, what do you do if you have too much later in the rpm range?" and I thought well since it is centrifugal, whay not add a wastegate to insure you dont go over a specific amount of boost? is this do-able? here is some food for thought:

http://www.sportcompactcarweb.com/te..._supercharged/
http://www.eng-tips.com/viewthread.c...=177194&page=9
http://forums.clubrsx.com/archive/in.../t-215998.html

but maybe someone on here already knows...

tom281

Yes it is doable; there was a recent magazine article. This is where I want to end up eventually..... for now I am going to settle for relatively moderate boost ~11/12psi to help get into it quicker and then reduce timing on the topend to help stay conservative.