GMC_DUDE

Why is that?

rgvsierra

iTrader: (7)

dont know if i speak for everyone, but i would think most people want to see 1/4 mile results vs dyno numbers.. get that test done now..

hellbents10

iTrader: (10)

lol, you so funny!!!!

Anyhow I am here waiting to put a 122 on a gen3/4 motor. I have played with plenty 112 gen3 combos.

moregrip

iTrader: (8)

Both are good tools.

Sometimes a good timeslip is more about setup than power, or track conditions, outside temp, elevation, lots of variables....... so those have to be taken into consideration as well.

They both serve a purpose.

parish8

iTrader: (6)

this is what i was trying to say above. i dont know why but it might have something to do with less boost down where the cylinder presures are the highest(mid rpms) and higher boost up in the higer rpms where the cylinder presure is falling off. on a truck like ours with pump gas that might be 2-3psi more peek boost before detonation with a procharger.

the hp would be equal at a lower rpm than in this test and then the d1sc would start to pull ahead in the upper rpms. for a most people the low rpm grunt of a magna is perfect for the way they drive but for a few that are looking for the best ET they can get and are willing to go with a prety high stall the d1sc will win the race.

i dont want it to sound like i am defending the procharger. if you really want to go fast get a turbo or the mp122 and make a drag truck that is still fun to drive. that is the down side i see to the procharger is you take all the driveability out of it to make it quick down the track.

Blown330

Easy...parasitic losses. The cetrifugals are more efficient compressors than roots or twinscrews...period. Think of it in terms of power transmitted through the blower drive belt. Both types place a considerable amount of force on the belt but all things being equal the centrifugals take less power. That means less stress placed on the rotating assembly. As far as driveability concerns I don't know where that comes from. Nobody I know with a street driven vehicle with a centrifugal supercharger as ever complained of that. F1R powered 03 Cobras and Lightnings certainly don't have any problems unless you count blower whine an issue...

BlownChevy

iTrader: (20)

This might have been true with the old style roots superchargers. The new hybrid roots with the APC will be FAR more efficient than a centrifugal any day of the week.

ranwalk

iTrader: (1)

I have to dissagree on the no drivability part-check out this dyno chart
pump gas, 13 pounds of boost D1SC on a 6.0 with cam, minor head work and the usual bolt ons with a Yank TT3000 converter.
https://www.performancetrucks.net/fo...chmentid=29714
Granted, the power doesnt come in as early as a twin screw or roots blower, but it still makes plenty down low.

Blown330

I know Eaton made significant strides in increasing the effiency of the roots type superchargers with the 122H and has an even more promising design in the future but at high rpm/high boost pressures seen in racing it won't outstrip the centrifugal by any means. That's basically the progression of a lot of street/strip cars and trucks...start with a Eaton, swap to a KB/Whipple, move to a centrifugal, then finally a turbo. Sal at PSP did pretty much that exact thing along with several 03/04 Cobras. Same engine, different compressor, and each time they made more power and ran quicker times. I will agree that the Magna can close the gap but it won't eliminate it.

parish8

iTrader: (6)

if your going with a procharger and you want to make it shine at the track you will need a 4000rpm stall. what does that chart look like at 3000rpm? what does it look like at 2000rpm where you are most of the time? with a turbo, big magna or big screw you can have lots of fun low end tq and high hp too.

you dont have to have a high stall converter to run a procharger and the driveability might not "suffer" but you will be waiting for the power to come on.