Dynamometer Results & Comparisons - Take A Look At My Graph

I showed this graph to another member here and he suggested that I post it up for the experts to look at as neither of us are Dyno Graph experts. The 2 graphs are open exhaust and closed exhaust. See any thing wrong here? Mods are in my signature.

Looks normal for an unlocked converter and the mods.

+1 with slowhawk.
and I'm sure the tune is perfect since Jim tuned :nod:

Thanks guys.......no way I know of to lock the converter on my 2004R. It has to be in OD first.

Hmmm. Where is your MPH then? She is definitely laying over on the top end of the track.

what kind of springs are you running?

I personally had problems running a tfs head with harland sharp rockers. I had 660 lift springs(5K miles) with HS rockers, stock tfs valves(intake valve weighs about 110 grams)

my 383 with 225 tfs heads fast 102, big cam etc. 6 speed s60 made 450/420

I put in LS3 turned down hollow stems, fresh .675 springs and yella terra ultralight rockers, the car gained 40hp/30 tq through the entire rpm band.

through a 3 inch magnaflow it made 490/455 peak at 6400 rpm.

looks rough up top to me

what kind of springs are you running?

I personally had problems running a tfs head with harland sharp rockers. I had 660 lift springs(5K miles) with HS rockers, stock tfs valves(intake valve weighs about 110 grams)

my 383 with 225 tfs heads fast 102, big cam etc. 6 speed s60 made 450/420

I put in LS3 turned down hollow stems, fresh .675 springs and yella terra ultralight rockers, the car gained 40hp/30 tq through the entire rpm band.

through a 3 inch magnaflow it made 490/455 peak at 6400 rpm.

I do believe that the springs in my tfs heads are the .660's and I have heard that the tfs heads have heavy valves. Picking up 40 hp would be great. Sounds like its time to save up for the valves, springs, and rockers. Thanks for sharing your experience.

looks rough up top to me

Agreed! And it could be related to valve control in the upper rpm range like 2002silverz28matt said.

Hmmm. Where is your MPH then? She is definitely laying over on the top end of the track.

Could be the valve control problems mentioned. This wouldn't be the first time I heard it. Time and money will tell.

My graph was smoother than that and I was having float as pointed out to me by Shane from Thunder Racing here.

I got second opinions from some engine builders on the Chevelle board and they agreed.

On tear down I found 2 trashed lifters and 8 cam lobes which had at least some damage (a couple were chipped even). This was at only 5800rpm with stock valves and rockers.

I do believe that the springs in my tfs heads are the .660's and I have heard that the tfs heads have heavy valves. Picking up 40 hp would be great. Sounds like its time to save up for the valves, springs, and rockers. Thanks for sharing your experience.

I would definetly take it to a shop or somewhere to get a professional opinion before you spend big money on the valvetrain. I honestly think the biggest problem is the HS rockers. You could just throw a set of stockers on there and see if it makes a difference. Or if you are planning on putting an intake on sometime down the road, do that first to make sure the intake was not the bottle neck.

The spring pressures on your 660 springs compared to my 675 springs are virtually the same, only reason I replaced mine is the car was coming apart and my springs had quite a few miles on them.

I would start with the rockers and go from there, so you dont end up wasting money.

My graph was smoother than that and I was having float as pointed out to me by Shane from Thunder Racing here.

I got second opinions from some engine builders on the Chevelle board and they agreed.

On tear down I found 2 trashed lifters and 8 cam lobes which had at least some damage (a couple were chipped even). This was at only 5800rpm with stock valves and rockers.

Thanks for the info. I sure hope I don't have any trashed parts. The engine has less than 1000 miles on it.

I would definetly take it to a shop or somewhere to get a professional opinion before you spend big money on the valvetrain. I honestly think the biggest problem is the HS rockers. You could just throw a set of stockers on there and see if it makes a difference. Or if you are planning on putting an intake on sometime down the road, do that first to make sure the intake was not the bottle neck.

The spring pressures on your 660 springs compared to my 675 springs are virtually the same, only reason I replaced mine is the car was coming apart and my springs had quite a few miles on them.

I would start with the rockers and go from there, so you dont end up wasting money.

TFS doesn't not recommend stock rockers with their heads. The springs have less than 1000 miles on them. I do know that others have replaced the TFS intake valves with turned down LS3 valves. I plan to contact TEA and see what the cost would be for a bowl clean up and the LS3 valves. Winter-time project.