I was wondering those with d1 prochargers when you begin to "see" boost on gague vs RPM.

At this point is do you feel an increase in power, if not when does it be come noticible? Lbs boost and RPM

Secondly,
With forced induction do the rpm limitations of the tpi system change? in other words tpi usally choke out at 4500 ish, is the rpm range wider with boost?

Thanks
Tom

 

depending on the load of the engine is when boost will start occuring...on the street i can start building boost at around 2500 to 3000 rpm's. and yes it is very noticable...

and yes the limiations still exist with the TPI system....my car stopped making power at around 4800 rpm's on the dyno....

later
larry

 

yep, mine stops around 4500-5000. my boost starts around 3000- rpm

 

With the 4" pulley I get this from my data logs.

RPM--PSI
3000-2.5
3500-3.5
4000-4.8
4500-6
5000-8
5500-10
6000-12

Around 3800-4000 is when I start to feal that I have a supercharger on the car, even then it's not crazy fast like I was hoping it would be.

 

Thanks all of you guys for the info, Just what I was looking for.

Tony, are you sort of dissapointed in the supercharger? Do you think that the money is better spent like on a 400 small block build up?

The reason that I was leaning towards boost is that I still could cruse and get decent gas milage.

Let me know you thoughts

 

Well if I can't really say I'am totally disappointed I did go from a 14.4 with the same 60' to a 12.99 and a gain of about 10 mph. If what these guys say is true and they are out of power at 4500-5000 on the dyno then my improvements make sense with the boost that I'am making at that RPM.

If your trying to get the most for you money then heads, cam, and intake is a very good option, just with the blower you don't have to mess with the engine putting it on and you get to keep you drivability which is nice. I plan to swap my pulley here in the next few weeks to a 3.4", hopefully that will put a smile on my face and maybe some crap in my pants

 

Maniacc: curious .... what numbers did you get on the dyno?

 

311 rwhp @5000rpm....346 rwtq @4250...

later
larry

 

3000 until you see boost??? thats worse than a turbo!!

you should feeling boost at 1800... are you guys sure there isnt something wrong?

my turbo Typhoon hits boost at 2200..

your superchargers are belt driven and it "should be" instant or close to it

turbo lags because it needs the exhaust to push the other side of the compressor..

man that makes me not want a SC

 

I think your thinking of a roots style of supercharger, a D1SC is a centrifugal supercharger, look it up.

 

MY old p600 made 7lbs at 3000 rpm and 9 at 5800.You need to calculate your max blower speed and figure out your max engine rpm and get your pulley to match those parameters.
I just changed to a D-1 and am running 81 tooth crank and a 40 blower for a max blower rpm of 61139 at 6800 engine rpm.

 

Well that explains a lot, I was wondering why those guys with there old p600's did so well in the 1/4 mile, they had way more boost down low!!

 

So if you want the boost to occur quicker down lower and say I have a max engine rpm of 5500. I come out with an answer of :

4.5 (internal ratio)*5500(engine rpm)/62000(blower rpm max)=

2.505 is the pulley ratio, where your ratio was basically 2.

Where could I look to determine what size pulleys I would need to get this ratio? I did not see anything on prochargers site.

 

The P600 internal step up is 3.05:1 with a max blower speed of 60000. I ran a cog on mine with a 81 and a 26. this put me at 55111 rpm blower at 5800 rpm engine. I had 11lbs on my worked 355 and made 500 hp to the wheels. When I ran a serp belt I used the 8" dia. lower with a 2.7 upper. This combo made 9lbs of boost at 5800.

ATI recommends running 5000 rpm below the max rating for their blowers. They have no catalog of their parts. You will need to call there and talk to one of the techs to get what you need. I have a 8" 12 rib, 2.7 12 rib and the 12 rib idler if you are interesed.