Dyno'd the TA today, expected more HP
 

I dyno'd my TA today, it was running rich as hell so i had them retune it. First run was a 379rwhp, needless to say, with the mods in my sig. i was pissed. They leaned it out and i got a 385 on the 2nd run, leaned it out a little more and got 391 for the 3rd run. I expected this car to dyno over 400 to the wheels easy so i was a little unhappy with the results, but 391 sounds alot better than the 379 i had with it running rich(11.9 WOT). The guys at Speedtek said all 98's seem to dyno lower than 99+ LS1's, they think it has something to do with the computer cause thats the only difference between the LS1's they've dyno'd. They dyno'd 98 and 99+ LS1's with the same mods and the 98 always seems to dyno less than expected. I didn't even know the 99+ had a dif computer till today. Any of you guys with 98's have similar lower than expected results at the dyno? BTW, my final numbers were 391rwhp/374tq

Seems a little low but i didn't see a ls6 intake in there, that should get you over 400whp. Also are there number corrected.
Steve

The year model you have makes little difference in potential hp once you go heads/cam. The fact that you're running a forged motor with Patriot heads and nice size cam and are unable to break 400 rwhp is puzzling. Was this on a Dynojet or Mustang dyno?

i Forgot to add in my sig, i do have a LS6 intake, and it was a dynojet. But this motor does need a smooth bellows and the dyno run was with catted y-pipe. I'm thinking about replacing the cats with some flo-pro twisted mufflers and see how much that helps.

I thought the year made no difference too but the guys at speedtek swear that every 98 they've seen has put down less HP than expected and 99+ LS1's with the same mods put down like 20 more HP than the 98's.

For what it's worth, I only lose about 2-3 rwhp with cats. Don't know if you'll like the sound or smell of an off road y-pipe. The smooth bellows is a cosmetic mod as it has been show to make 0-1 rwhp.

You appear to be down on power. Do you have confidence that your tune is as good as it can get?

He said he could lean it out more and prolly get me 400 or a little more, but i dont want it running too lean. It's already like 12.7-13 at WOT, that's lean enough.

What plugs are in it? and you have a 160stat? cam was degreed, all springs and pushrods are tip top.

I know you may only gain 3 rwhp without cats, but your cats are different than mine, so mine may be more restrictive, making me lose more power than yours make you lose. You never know. But yeah i doubt they're costing me more than 5 rwhp

i'm running TR55's gapped at .050 and i do have a 160 with programmed fans

the tr6 might help get you some more timing..

I thought about the TR6's but i doubt it'll make much difference over the TR55's. I might even be able to get more timing put in my tune, but it could cause knock or pinging, which right now i'm getting none of either

BS what Speedtek said.

98's can make as much power as the other years with the right mods.

I have a 98 and I'm making 389rwhp with a Hotcam and stock heads (never taken off), and I should hit some much higher numbers when I put in a real cam!

Here's a dyno graph.
http://www.cobraeater.cz28.com/image...r%20Hotcam.jpg

I gained about 7-10rwhp when I took off my cats, but I was using carsound cats and not the random tech metal matrix cats I'm assuming you're using Patrick.

Try the sound of some true duals without cats! :devil:

He doesnt have anything left from a 98 motor so they can base the lack of HP from that..forged pistons, crank which is probably drilled and chanfered for oiling, he has long tubes, patriot heads, 10.8cr over the 10.2, a much bigger cam 224r,.. hey White what are your valve train specs...model spring,rods,lifters etc...

That's the problem, i bought this TA already modded and the previous owner is having trouble finding some of the paperwork so i dont know all the specs on some things. The springs are not stock their patriot Gold something, i forget, the lifters are comp oem replacements, not comp-r and the pushrods are stock.

Our setups are nearly identical save for the bottom end. Your numbers do seem a little low and I would start looking into things especially if someone else did the install of your mods. The Carsound/Magnaflow cats don't flow as well as the RT MM cats and I lost 9rwhp and about equal torque on my TR224 cam only setup two years ago.

My cam is actually the TSP 224R, i dunno how much different from the TR224 it is tho. But yeah these cat's are prolly gonna have to go, i'm thinking about going with some flo-pro twisters in their place to keep the rasp down. And the cats are the ones that came with the FLP longtube setup. I dunno if they're better than Carsound cats or not.

I guess i need to keep in mind that the 391 pull was in 85 degree weather, and it was the 3rd run on the dyno so the motor could have been a little tired.

maybe its the pushrods . the cam is a high lift cam, you got high lift springs and oe comp lifters, i dont think the stock pushrod is keeping up with highlift cam and springs. they are the middleman in the system.

yeah thats my current problem, i want to change the pushrods, but i need to find out what length i need first, cause i have a little valtrain noise so i'm wondering if the pushrods aren't the right length. Cause the block's been decked and it has a different cam, so pushrod length could easily be off