haole_boySS

iTrader: (1)

Previous set up was cam only TR 230, all bolt ons, hooker long tubes, custom 3" y pipe thru a cutout, ls6 intake, jantzer TB,steel flywheel, single disk kevlar, 12 bolt w/4.30's. I put down 393 hp and 385 tq. The car peaked at about 5800 and pulled strong all the way till 7000.
Well, I went to the dyno yesterday with my new set up. The drive train was the same but the motor was completely different.
Now I have the Futral F11 cam on a 114 lsa, AS Stg2 5.3's, HS rockers, Comp stock replacement lifters, 7.4 pushrods, Rollmaster dbl chain, TR ported oil pump, 28.8 injectors, March fluid underdrive pulley.

I put down a whopping 385hp and 363 tq. I peaked right about 6k and then dropped off like I had valve float at 6400. I am completel confused with this. My tuner was adding and subtracting fuel and timing trying to get my car to react and it never really did. The drastic changes that he made only netted a +/- 2-3 hp difference. With the changes that he made, you would expect to see a 10-15 hp drop or gain at least.

Any and all help is greatly appreciated. It really sucks to spend all that money and lose power over a cam only setup.

Andy

ataylors

iTrader: (2)

are you sure you didnt static the injectors?

ataylors

iTrader: (2)

valve float can easily seen with a vaccum gauge.

Another_User

It could be a lot of things. What was your AF ratio? That would at least tell you if it was a fueling issue. What bar are the 28.8 injectors rated at? How is your fuel pump/filter? If it's not fueling, what ratio rockers did you put in? What is your effective lift? What springs are you running? Did you check your valvetrain geometry after all those changes? It could be a lot of stuff...

haole_boySS

iTrader: (1)

The rockers are 1.7, the air fuel was in the 13.5 range no matter what was changed with HP tuners. Grannysshifting did the tuning and he is stumped too. He was making big changes with the A/F and timing and it would only yield a 2-3 hp difference.
I am assuming valve float because of the way the power dropped off up top. It was like the clutch was pushed in. Unfortunately, I am not totally sure what springs I have. Acording to the posts that Jay @ AS has made, I am pretty sure I have either the Comp 977 or 978's.
As far as valve train geometry, I tightened the rockers up to 22 ft lbs, thats all.
I assume the pump and filter are ok since the can never tried to go lean even when granny richened it up.
I was "told" by Jay that the heads would yeild 11:1 compression. I am using hardened 7.4 pushrods, HS 1.7 rockers, TR55 plugs. The cam is a Futral F11 227.9/230.4 576.3/597.2 on a 114 lsa, +4 degs of advance.

I am completely stumped. Its like I put on a set of stock 5.3 heads and not the stg 2 port job heads that I paid for.

HumpinSS

iTrader: (1)

Can you postthe dyno sheet

AgentOrange

was PE active. Is CAT-Overtemp disabled, etc..

HumpinSS

iTrader: (1)

I would assume cot is disabled because it was running pretty lean

haole_boySS

iTrader: (1)

I dont know about the "PE" or not. The guy doing the tuning knows his ****. And yes, the cat over temp was off. I am going to re-torque the rockers and change to a tr-6 plug.

Magic Chicken

iTrader: (1)

Was there a temperature difference between the 2 days you went to the dyno? Cold day on the old setup, hot day on the new setup?

haole_boySS

iTrader: (1)

I just recently dynoed on Friday and it was hot as hell. The time before when I dynoed was almost a year ago and I dont remember if it was hot or not.
Either way, it wasn't hot enough for me to lose 35-40 hp. At least I wouldn't think so.

LEATHL_WS6

Please keep us posted on this. I am having the same problem but no drop off at high rpm. Mine makes power all the way to 6800. But I'm short at least 30hp. I'm running a 5.3 that has been milled .020. 7.4 PR HS rockers. I swung the timing from 32 to 24 and there was only a 3hp difference.

Did you do the wire mod by chance? Where you move the computer wires out of the engine bay a through the fender?

Rob

Magic Chicken

iTrader: (1)

You'd be amazed at how much difference the weather makes. Assuming you have some kind of scanner, did you happen to see what your Intake Air Temp was and how much advance you were getting?

Magic Chicken

iTrader: (1)

Never heard of this, what is it supposed to do? Have any websites handy for more info?

LEATHL_WS6

Doesn't do anything but make the engine bay look cleaner. The wires have to be extended by 4inches or so. Just wondering if that may cause computer problems. I have done this to mine. I can't see it making a difference though as all of the wires were just trival stuff. Like Traction Control washer fluid etc. none were engine control wires like map, maf, injectors or such.

Rob

haole_boySS

iTrader: (1)

Nope, I never did the wire mod. Grannysshifting also turned down my timing from 30.5 degs to 24 degs and only had a 2-4 hp difference. I dont recall what the IAT was but with 2 huge fans blowing against the air dam it couldn't of been that hot. We were in a Air-conditioned garage and the exhaust was going outside.
Like I said, I made 394 385 cam only with the TR 230. I dont remember the air temp that day, but I know it was summer time. Now that I have changed to a bigger cam (Futral F11) and AS 5.3 heads I lost power? I can't swallow that I would lose that much from just IAT. The heads would have to give me something right??

LEATHL_WS6

I'll agree with you there. Your in the same boat I'm in. I went from some crappy heads that flowed 280 10.5:1 at best compression 224 228 cam and made just over 400rwhp. Now I have a set of 5.3 heads flow 300 that have been milled .020 for 11:1 cr. 231 237 cam and made 400rwhp. Just don't seem posiable. Temp I know were similar for me, I was on the same dyno, same guy running it. I pulled 10% fuel from PE and the AFR did not change? COT was off.

Damian

iTrader: (89)

Either in the valvetrain, tuning, or heads. That cam makes excellent power

ArKay99

iTrader: (1)

I would check lifter preload. You may have no float, but the valve open and closing events may be mushy from too much preload, or opening late and closing early from not enough preload.

LEATHL_WS6

If hes running HS rockers like me there is no adjustment. Just torque them down. I have checked mine from 0 lash to 22ftlbs is between 1/4 and 1/2 turn. Seems right to me. I'm running a 7.4 prod.

I know the 231 makes power thats why I'm dumbfounded. I'm checking into my computer being bad. Everything else seems to check out.