How much 2000-3500 RPM power?

**Intrepidman** · 06-23-2010, 10:58 AM

Does anyone have a dyno graph starting as low as 2000RPM or even 2500RPM with a before and after for a head/cam swap.

I ask because I have a 2002 Trans am with the usual bolt ons (headers, cat-back, various intake parts) and I'm soon to be throwing in a cam somewhere in the range of the "Texas Speed 228R" along with 215cc Trick Flow heads...and I might even upgrade to a FAST 92 intake with matching TB.

I know I'm going to pick up a lot of HP and TQ in the 3500-6500rpm range; but I would like to see, what if any, gains I might make in the lower rpms. (the range I use while autocrossing in 2nd)

A separate but related question - I know how converters are supposed to work, but I've never had the chance to drive a car that was equiped with an aftermarket piece.....By replacing the stock torque converter with something similar to a yank 3200 will the power I make below that rpm "appear" to be greater? That is to say, (when racing the car hard) will it feel the same as picking up more hp/tq in that rpm band or will it "drive differently".

**Spaz** · 06-23-2010, 11:27 AM

Originally Posted by Intrepidman

Does anyone have a dyno graph starting as low as 2000RPM or even 2500RPM with a before and after for a head/cam swap.

I ask because I have a 2002 Trans am with the usual bolt ons (headers, cat-back, various intake parts) and I'm soon to be throwing in a cam somewhere in the range of the "Texas Speed 228R" along with 215cc Trick Flow heads...and I might even upgrade to a FAST 92 intake with matching TB.

I know I'm going to pick up a lot of HP and TQ in the 3500-6500rpm range; but I would like to see, what if any, gains I might make in the lower rpms. (the range I use while autocrossing in 2nd)

A separate but related question - I know how converters are supposed to work, but I've never had the chance to drive a car that was equiped with an aftermarket piece.....By replacing the stock torque converter with something similar to a yank 3200 will the power I make below that rpm "appear" to be greater? That is to say, (when racing the car hard) will it feel the same as picking up more hp/tq in that rpm band or will it "drive differently".

everyone will have a different read out yet similar... why not take it for a few pulls on a dyno before hand???

**Hurley711** · 06-23-2010, 12:06 PM

http://ls1.com/forums/attachment.php...3&d=1240662680

Mods in sig TR224 cam 5.3 PRC heads etc etc

**Marc 85Z28** · 06-23-2010, 12:30 PM

Autocrossing a vehicle with a higher stall torque converter is going to be a major PITA. The car will be hard to control and the heat buildup will be nearly impossible to overcome, no matter how kind of cooler you run. Additionally, if you do go with an aftermarket converter, your whole quest for power in 2000-3500rpm range is pointless - you'll NEVER see that kind of RPM at WOT.

**Intrepidman** · 06-23-2010, 01:13 PM

Autocrossing a vehicle with a higher stall torque converter is going to be a major PITA. The car will be hard to control

How so? Will it make feathering the throttle impossibly delicate or twitchy? Or will there be some awkward locking/unlocking of the converter that will cause delayed lags and serges of power onset as the throttle is being feathered? (kind of like the way idling around town at 10mph feels on a stock converter)

the heat buildup will be nearly impossible to overcome, no matter how kind of cooler you run

A 70 second run with the fans on high (slp switch) followed by a 4-5 minute cool down (with fans still on high) is about what the car will be up against. Will it really cook itself in 70 seconds, or were you thinking of longer laps?

if you do go with an aftermarket converter, your whole quest for power in 2000-3500rpm range is pointless - you'll NEVER see that kind of RPM at WOT.

I take it you mean the engine is basically going to go from whatever rpm its idling at (as I brake and round a corner) to the max stall speed in an instant, as soon as I get onto the gas?
Bear with me, as I said I haven't had the chance to drive anything other than cars with stock converters. But if WOT does indeed produce idle to max stall speed in an instant, is there some middle ground using part throttle, or are the functions of the torque converter not governed in that way......I'm just asking based on experience with the stock stall now (being what, 1500? 2000?) If I go to WOT the RPMS rise fast, but at part throttle it seems pretty even, there's no obvious feel to the torque converter..stalling up, lock/unlocking...whatever its doing. The only time it feels sloppy is basically idling around in first gear at speeds when the tire rotation is slower than its idling engine RPM would dictate, if they were mechanically locked.

**Frost** · 06-27-2010, 12:17 AM

Originally Posted by Marc 85Z28

Autocrossing a vehicle with a higher stall torque converter is going to be a major PITA. The car will be hard to control and the heat buildup will be nearly impossible to overcome, no matter how kind of cooler you run. Additionally, if you do go with an aftermarket converter, your whole quest for power in 2000-3500rpm range is pointless - you'll NEVER see that kind of RPM at WOT.

You're right but even with a stock stall there won't be any 2000-3000 WOT because the car will [automatically] downshift.

**Intrepidman** · 06-27-2010, 06:48 AM

in "3" will do just that, but in "2" it just stays put in that gear and never drops down to 1st....I count on that fact when autoXing, if it did downshift to 1st I would mostly likely be sending the back end around constantly. (every time I got onto the gas, coming out of a hard corner)