"Kill The Bottom End???"
Thread Starter
Pro
Joined: Apr 1999
Posts: 533
Likes: 6
From: Poinciana Florida
"Kill The Bottom End???"
I recently changed cams, ignition systems and went to a larger blower pulley. As a result I'm back to 595 rwhp@5700 rpm with a 700 R4 trans. This is surprising with 2lbs less boost at the top. Obviously the smaller duration cam is doing the job with no blow by from overlap. The larger pulley is giving me about 3 lbs less boost in mid range with a loss of 80 to 50 less rwhp moving up the curve. If I can keep rubber on the tires, and gain traction I can live with this.
If I go back to a smaller pulley I can get back the lower end plus pick up about 30 horses at the top. But Why. Has any one else purposely and successfully killed the bottom end power in this manner??
If I go back to a smaller pulley I can get back the lower end plus pick up about 30 horses at the top. But Why. Has any one else purposely and successfully killed the bottom end power in this manner??
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
If you are happy with the way the car acts then I'd say leave it. You know you'll want to upgrade it later when you get used to the power again.
The problem is that with the 700r4 you drop so much in rpm that the midrange power/torque is a big concern.
Do you have the cam specs of what you had and what you have now. Its kind of interesting that the peak power didn't go down shift in the rpm range when you went to a smaller overlap cam.
The problem is that with the 700r4 you drop so much in rpm that the midrange power/torque is a big concern.
Do you have the cam specs of what you had and what you have now. Its kind of interesting that the peak power didn't go down shift in the rpm range when you went to a smaller overlap cam.
Thread Starter
Pro
Joined: Apr 1999
Posts: 533
Likes: 6
From: Poinciana Florida
I was surprised too. The initial cam was a CC 305 which I was pleased with. The current cam is also a CC item with a 224/228 duration.The lift is 581/588.
The torque dropped from 596 to 571. However, peak torque climbed to 5300rpm from 4800rpm. The new cam appears to have better "manners" then the 305.
The car along with me is spending time in Orlando. I now have more time on my hands. If I don't buy a business to keep busy; I'll trade in my old Snap On tools for metrics and once again start playing with the car.
The torque dropped from 596 to 571. However, peak torque climbed to 5300rpm from 4800rpm. The new cam appears to have better "manners" then the 305.
The car along with me is spending time in Orlando. I now have more time on my hands. If I don't buy a business to keep busy; I'll trade in my old Snap On tools for metrics and once again start playing with the car.
