Not promoting KB but check out this test which compares very well to other test that I have seen and that others have posted.

Essentially torque is lost at lower RPMs and only results in a small gain high on top. Most interesting is the higher heat generated right across the board.


http://kennebell.net/superchargers/f...ting54_26L.htm

 

I don't believe anything that KB ever says, and that's one more reason why.

While SOME trucks do lose some low end torque, there is also usually a 20-25hp GAIN over 4500 rpms. That graph is a joke.

 

The test was done on a stock truck using a 2.75" upper pulley. The results match the testing by a certain vendor that was done a few months ago that demonstrated that gains were only achieved on engines using 4 to 6psi pulleys above 4500rpms as you stated. Porting at stock boost levels only resulted in loss torque.

The vendor's tests on 6psi pulleys showed torque loss of up to 40ft/lbs below 3500rpms and gains of 10ft/lbs and 20 to 30hp above 5000rpms which is really sub-optimal especially for street use. Those 5000lbs beasts need all the torque they can get at low rpms.

 

my truck gained 33hp and 35tq to the tires with a ported eaton.. everyone i know who has ported there eatons has Gained power, never a loss..

 

You know me and I lost torque

But, in the ported eatons defense mine isn't a fair comparison because my first tune was an aggressive non-dyno tune, then came the eaton and much safer tune.

It doesn't feel as fast, but then again it's all in the tune. When I have play money and get on the dyno for custom tune, that will be the tell.

 

No one cares about peak numbers...
Like Tim says:

"its all about the area under the graph"

 

i guess.. im lookin at my chart now i made peak HP at 4700RPM peak TQ at 4000RPM... im pleased with it.. im very tempted to bolt my Whipple on and really lay the numbers down on the stock block and listen to it explode.. HAHAHAHA

 

This is old new and this horse has been beaten to death. Porting a stock blower is improving a stock blowers performance to an extent. It is in no way a substitute for an aftermarket blower.

I picked up dyno numbers with my port. Nothing really in et, but a solid 1 mph gain in the 1/4.

 

All the ones I have seen (running 6lb pulleys) lost in the 1/8 and gained in the last 1/8 because the gains take place above 4500rpms. If that is what someone wants, then that's fine.

 

To use the term "porting" is very general.

There is an art, a craft, a science if you will to porting anything.

I can grind the crap out of my blower and say I have a ported blower.

Someone can spend thousands of dollars, bench flow testing and dyno testing a port job.

Again, this ported blower thing has been beat to death on every lightning board i belong to. As far as I know, there have been no ported a stock blower break throughs.