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I was wondering if anyone had dyno numbers and opinions on drivability
for a cam that would fit my LT1. I know of the LT4 HOT cam, but I don't
want to go with that because 1) it only makes the HP way up high (5500 up),
2) I hear that you have to give it more gas to start the car from a stop.
What cam specs should I be looking at if I want 30 hp gain but smooth
idle and long valve train life?
I am running a Comp Cam custom grind camshaft in my LT1. It is a little less radical than the GMPP Hot Cam. Cam specs: 212/224 duration @ .050, 520/536 lift-1.6 rockers, 112LSA. This camshaft idles pretty smooth, little if any loss of low end torque, and is really strong above 3000 rpm's.
If you're running a 6-spd you're driveability won't suffer at all with the Hot Cam. It's true that it makes good power up high but nowhere does it really make less power than the stocker.
I have a Cam that is very similar to STL94LT1's. It is a Comp Cam custom grind 210/224 with 112 LSA. The lift is .501/.499 @ .050 using 1.5 RR's, and .534/.531 with 1.6 RR's. It idles very smooth at 900 rpm with just the slightest lope to it.
I did this mod with a number of others so it is hard to say what it got me powerwise, but I'm sure it should be worth at least 20 - 25 hp. Here was my dynosheet from last year. I will be getting it done again after the gears and tuning get done...
Did both of you replace your stock springs? with what? And, did you
replace the lifters when you changed the cam? If so, how much did
the new lifters cost?
Did both of you replace your stock springs? with what? And, did you
replace the lifters when you changed the cam? If so, how much did
the new lifters cost?
My springs were changed with the head work, not sure whick springs were used.
Also, I reused my lifters. Unless you car has very high mileage, you can reuse yours.
I'm using the GMPP 846 cam and love it. Bigger still than the HOT cam but drivability is great. Idles nice but slightly noticeable lope. With LT1-edit I tuned it to run quite smooth and no loss of drivability. On the dyno it produces a nice flat torque curve with more than 325 lb/ft everywhere between 2000 and 6000 rpm. Peak torque is 356 lb/ft at 4000 and peak HP was 368rwhp at 6000 rpm. It's 222/230 deg duration @ .050
Did both of you replace your stock springs? with what? And, did you
replace the lifters when you changed the cam? If so, how much did
the new lifters cost?
I replaced both. I went with the Comp Cam Double Springs (986?) and the Comp Cam Hydraulic Roller Lifters (R Series). I beleive the lifters were $279 but it was a couple of years ago...
I was wondering if anyone had dyno numbers and opinions on drivability
for a cam that would fit my LT1.I know of the LT4 HOT cam, but I don't
want to go with that because 1) it only makes the HP way up high (5500 up),
2) I hear that you have to give it more gas to start the car from a stop.
If you can hold on a few weeks before buying something, I'll have dyno numbers and I would be able to show you mine at some nearby cruise spot. like out at BWI airport. I'm getting the LT4 hot cam right now. There is no loss down low and there is no drivability issue ----- If you have a 6 speed
It probably wouldn't work so well with an auto. The LT4 after all was 6 speed only. Which do you have?
The first question my engine builder asked is stick or auto. He looked at my car and said no problem with the cam lope because you have the six speed.
If you have an auto and aren't going to go with big rear gears, then you are limited in the cam specs that will work for you.
'94,
Meeting near BWI would be super! I work in that region. My car is a six
speed, so the drivability would be a good comparision. Are you doing anything else with the car?
luvmy92,
You mentioned a good idle and minimal lope. Do you have to give it more
gas to start or does it feel like stock? My car might be used in stop/go
traffic from time to time...
'94,
Meeting near BWI would be super! I work in that region. My car is a six
speed, so the drivability would be a good comparision. Are you doing anything else with the car?
Custom ported heads by a builder. The car is finished and running, but they won't let me have it until they can take it out for a hard run. And the roads in Pa are too messy to let that thing loose on cold Goodyear GSCs. I might be able to get it next week.
Heads and Hotcam, that's exactly what I'd like to do if the price is
survivable.
Who is your builder?
Sweitzer's Performance, Steve Sweitzer in Jersey Shore, Pa.
He won't take you in unless he knows you. Even though he knows my brother from high school, he wouldn't take me in until he looked over my car and thought it worthy. He has enough work from racers.