somone of u may have seen this thread at another site but here goes

had AFR 205s and a 226 228 114 cam put on my 02 zo6. I also had em put in new pushrods, SVO 30 injectors, ngk plugs, and a new timing chain. the car had Vram intake SLP headers Y pipie Stock cats, and borla muffler. the car only gave me 8 extra rwhp. here is the dyno graph















fuel presure was not an issue, exhasut flow was not a problem, cats are not clogged. vacum check was fine, compression check was #1 175 #2 170 #3 175 #4 170 #5 175 #6 170 #7 170 #8 175.

as u can tell there is a huge drop in the numbers. When i picked the car up it felt REALLY SLOW. I had the car tuned, and that is the graph from the tune. I am not sure what the issue is but the first pull on the dyno only yielded 350 RWHP that is 27 less than the car had when it went in. It was only after tunning that the car pulled 375.

any ideas

 

i dont know a hole lot but i know that a big reason is because the ls6 heads are so good already and since you put another puny cam in you didnt gain much....your cam probably isnt that much better than the ls6...and the heads ls6 heads are really good....if you would have jsut stayed with the ls6 heads and put in a big cam you would have been alot happier with your gain

 

same heads and cam on a car with similsar ecxhasut yeilded 480 RWHP. of course the guy did add a 90mm intake and an electric h20 pump I am expecting 420-440, look at the graph dude somthing is a matter

 

yeah somthin is way out of whack on that. you should definately be seeing 410+RWHP. maybe go to another shop and have it dyno tuned there and see what happens.

 

if the car felt "REALLY SLOW" why didn't you turn around and take the car right back?
Did the above car (that made 480) have cats on it is there a possibility your car just dyno's low have you taken it to the track? or are you just after a dyno number? who did the work on the car?

 

With your HP peaking at 5450 I would guess that the cam has been installed one tooth off. Your cam and crankshaft gears might not have been lines up dot-to-dot or your cam might not have been ground correctly.

John

 

What springs? Looks like that combo is peaking WAY early. Maybe one of the experts can tell from the graph, but I'm gonna guess valve float. That should be peaking at 6000 at the earliest, definatley not 5400.

Edit, somebody beat me to it. JNorris could be more on the right track than me.

 

I agree. The cam must be advanced to peak that low, also could be valve float. I hope you didn't just swap over the stock springs to the new heads. Those are pretty crap numbers, especially since it feels slow as well.

 

I would say that it isn't valve float. Although the drop off is steep, the graph is really smashed up compared to the DynoJet graphs we usually see, so it will make it seem like the drop is worse. Usually the graph will get VERY wavy with valve float.

But I agree with everyone else that there indeed is something wrong. I'd say its a tuning issue. Where did you go for the tune? How new are the cats? Cats in any instance will rob quite a bit of power. Not that much though. Your torque curve is also pretty unstable. Perhaps a faulty injector is to blame. Any missfires?

 

Why does the graph say flywheel HP?

 

Man a 226/228 114 should peak around 6100 +/-
I don't care what the tune is, something is wrong on the install.

Had you just swapped AFR's "out of box", you would have seen 22 rwhp and that is with a drop in CR.
were those heads milled?

And a 226 makes more power than a LS6 cam.

Who did the install for you? did you degree the cam?

 

I have not taken it to the track, I am looking for power, I will not name the installer or the tunner becasue I feel that if a mistake was made and it gets fixed at no cost there is no reason to start internet BS flying. I didnt take the car right back becasue I was busy. The cam was degred, like i said above there is no flow problem from the cats we checked they are clean. the graph says flywheel hp casue that is the way the printout reads it is an error it is actually rwhp the sptings are whatever comes on the AFR head from AFR. I have gotten no codes or missfires

if i missed a question i am sorry

it looks like people are saying the cam is a degree off, any other opinions

 

There ios no way a 226/228 114 will peak at 5450 rpm.

 

That set up should be good for 430rwhp. Something is wrong.

 

dude your cam is dergreed wrong.. or you have valve float.. take the car back!

 

IMO, you should start with the easy stuff. Make sure all your electrical connections are nice and tight, make sure the plug wires are in place, check out your spark plugs, what do they look like? Then you have to listen to your valve train. is it really loud? How much lift does that cam have? Where the heads milled? Maybe you have a vacuum leak? Pull your valve covers and make sure the push rods are the proper length, a longer push rod will hold your valves open and really reduce power. I know this isnt your main problem, but those cats and borla arent helping at all. IMO you need to check the very basic stuff before you go pulling the engine apart again. Good luck though, that setup should be sick when your done.

 

especially on a 346.

 

Something is seriously wrong.
Big-time installer error.

I made 412rwhp with a cam using the stock LS1 heads. You should be way over that.

Mike

 

electronic connections are fine, plug wires are in place. valve train is a bit louder but not loud enough to casue concern, there is no vacum leak that was checked push rods were checked cats were pulled and checked and were not clogged

 

Which is exactly why I am thinking the cam is installed wrong. You said it was degreed, but you didn't say what too. Are you sure it was degreed? If the cam already had the timing events changed (say a few degrees advance ground in) then someone "Setting it up" a few degrees advance or retarded would be making your valve events happen pretty far off of the pre-designed que and be causing some serious issues....like you are experiencing.