I recently drove a Vortech charged VW VR6 car and i noticed that the amount of boost was very proportional to the engine rpms which ofcourse was to be expected for a centrifugal SC.

But i noticed that it took at least 3500 rpm before it started making any boost and to be honest it was a bit dissapointing.

I'm aware of the fact that i shouldn't compare totally different engines (with setups) but i do wonder when you start noticing the SC on a LT1 in the usual setups/configurations, in other words does it also take half of the LT1 rpm band before the SC starts moving the needle on the boost gauge ??

 

My experience with all centrifugals is that boost is nearly proportional with rpm. For instance, 3 psi at 3000 rpm, 6 psi at 6000 rpm, and so on. . .

 

So downlow a SC doesn't do jack for an improvement in performance/torque right ?

 

It will, just not a ton...that's why a lot of people run 383s with a SC to pick up the action down low in the power band.

 

Alot of it will also depend on what pulley combinations are used along with the internal step-up ratio of the blower.

 

Well. . . if you gain 40% torque at 6000 rpm, then you'll gain 20% at 3000 rpm, and 10% at 1500 rpm.

 

Then again, who's in a drag race or rippin through gears and hanging around 2000 rpm anyway, so it all works out in the end....

Ken R.

 

Maybe he likes racing in 6th gear?

 

Ok, i get the picture.
Just wondering as it didn't seem logical to me to have a SC that needs to be used in the upper rpms which isn't exactly the area an LT1 enjoys itself the most.

Maybe a Lysholm type charger would be very usefull for instant power of the bat and stays efficient (unlike the roots type chargers) at higher rpms.
I do think installation is a SERIOUS problem with those chargers so forget that.

Oh for those that care (probably nobody) i have years of experience with a G60 (G-lader) supercharged 4 banger and i was used to having an instant 10 psi of boost past 2000 rpm, hence the dissapointment driving that VR6 engine with the Vortech which really started making boost past 3500-4000 rpm.


Thanks for responding.

 

You pulley the supercharger to hit the desired boost level at max rpm. If you want 12 psi, you pulley it to reach 12 psi at 6000 rpm. If you have a diesel, you pulley it to reach 12 psi at 3000 rpm. You see, it will make max boost at the top of the rpm range no matter what that rpm range is.

 

If you want boost in the lower rpms then put in a high pulley.
I have the 9 psi on my powerdyne and it starts building boost at 2500 rpm.
I can easily see 5 psi at 3500 rpm without going WOT.
At WOT I'll get up to 7psi.
I've got the stock cam and my engine shifts at 5200-5400 rpm.
I like having lots of torque where I drive all the time at the cost of losing the high boost at 6000 rpms.
Also not revving so high keeps my stock engine alive.
10,000+ miles so far on the S/C.

 

i bet the meth is helping keep that motor alive longer too.

sergio, when you made the comment about LT1s not liking higher RPMs youve got to think about the boost vs. engine rpm. NA the LT1 flattens out at high rpm, but you put a SC on it and then youve got more boost with more rpm. more rpm=more power.

the harder you rev the sc LT1 the harder it pulls. thats what i love about the supercharger. where the NA motor flattens out, these just keep screamin!

dont know about other guys' opinions but my LT1 definately enjoys itself when i rap it out. until my stock bottom goes boom. not yet though

 

Ok, it does sounds promising.

What about sound, it really depends on the SC right ? I've seen they have these so called Super Quite versions so i assume regular versions can become loud ??

 

My old setup was a P600-B Procharger. I really liked the performance on the LT-1 and the noise the gears in the blower made. Since they are a straight cut gear(unless it is a SQ)they make an uneven sound at idle( marble like sound) and a whistle when brought up into a higher rpm. This is from the slop or clearance between the straight cut gears. As far as the standard versions getting lounder, I experienced the opposite which should be the case if properly lubricated and taken care of. I have heard guys running oil addatives and quieting them down. I dont believe in addatives and only run RedLine synthetic which worked great the entire time i owned the kit. to me the SQ series or similar blowers just sounds weak. I like to be able to hear the damn thing, especially if I paid 4k+. Although there is the sleeper set out there that likes to be unsuspecing and then stomp the S**T out of the poor guy in the next lane. Ultimately, I went to a better power adder, PTK. Nothing like the sound of a turbo and a blowoff on an LT-1!!

 

i bet your turbo set up is a little bit faster?

the ptk turbos sound freakin sick!!!!

did you see the video of the turbo LS1 vs the 2003 cobra? i think his was a ptk....