Went to a Dyno party today...weather cool at about 49* and haven't had a dyno pull in over a year. I was expecting good numbers due to the cooler weather conditions. The shop uses the same kind of dyno that my tuner uses...a Dynojet.
My rwhp went from 449.8 to 403.2 and my rwtq went from a high of 423 to a 389 reading.... The motor feels fine...no codes. I use only Chevron 93 octane fuel and I don't think I had any bad gas in the tank.
This is with LT headers, ram air, cam, heads, elect water pump, etc. I think I'm going to be sick.....lol
I ran more than 403rwhp BEFORE the heads and water pump were installed a couple of years ago. I'm going to get back to my original tuner to see what (if anything) is wrong with my set up to cause such a hp/tq loss. What could possibly cause such a big loss in readings?????
Rob,
I wouldn't worry about it too much, there's a real good chance that the dyno isn't calibrated correctly. If your SOTP meter tells you that the car doesn't feel weak, then it has to be the dyno. Dyno numbers are just that, numbers! I have destroyed cars at the track that had pulled way higher dyno numbers than my car. By any chance, did the shop that did this pull for you have a tailpipe sniffer to take AFR readings during the dyno run? If so, check that against your original dyno pulls to see if maybe your fuel trims changed. By all means let us all know what happens when you get it back to your original tuner for a few more pulls.
In the meantime, just enjoy your beautiful car and don't sweat the "numbers".
Jimbo
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'03 EB/mod blue VE interior, LME-LS3 Stroker, AFR 225's and a nasty cam from Pete at V-MAX, 3" custom Powerstick exhaust and lots of attitude! Any questions? Z06 Fest member III, IV, V, VI, VII, and Winterfests 1&2. new times coming soon!
Yea, the had the "sniffer" in the tailpipe. The A/f showes a little lean. I'm just stumped...the car feels fine. I hit second gear a "little" hard on the way home and the Nittos easily broke loose at about 54 degree outside temp. There is no rough idle or misfiring. I know all dynos are different, but this is a huge difference from my last pull a year and a half ago.
I'll get to the local shop (MTI) next week to have them check out the motor and do some pulls to see what the numbers show.
Maybe a good excuse to get that D1SC I want and get to 600+rwhp....lol
Good luck with the issue. But no codes is a GOOD Thing.
Believe me.....Why you choose the ATI over Kenne Belle? Any personal reasons?
600 sounds about right! YOu deserve it!!!!
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2KC5 FRC MN6, Bad Head & Cam install, Failed Lifter, Burnt Clutch, Cracked Rotors, Bad Tune, Blown Piston, Blown Head Gasket, and faulty rockers.....but I still come back for more.....Installed/Tuned by LG Motorsports. Best 1/4 Trap: 11.94 Best Top Speed 121.10 on street tires at 1200 Ft ASL.[/center]
Rob, there could be several reasons, but you might check your plugs.
Don't know if you're running colder plugs or not but sometimes they can start going bad in a hurry.
Thanks for the replies...I'll get her checked out for sure ASAP and follow up with the results. It shouldn't be anything too bad...the car still breaks loose the rear Nitto tires, no codes, no check engine light and pulls from 1600-1800 rpms on the beltway without stumbling.
Looks way lean below 4500rpm. After that, not too bad. It may need a tune, but still don't think you'll pick up your peak horsepower/torque.
Yea, real lean at lower rpms...hope the tuner can get it right. Maybe the car wasn't hooked up correctly for the dyno...I hope that is all it is. There is NO WAY this motor would lose 46rwhp without running rough or throwing codes.
I'll follow up this thread with the results...may take a couple of weeks though. Having a Textralia clutch, hardened output shaft and Baer brakes pkg installed next week. This mechanic doesn't have a dyno, so after the install she goes to MTI for dyno tuning.
Rob, put her on another dyno. You can't loose 47 HP without something being terribly wrong. If the car feels just as strong as it always has, then it's probably the dyno, IMO anyway.
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Rob, put her on another dyno. You can't loose 47 HP without something being terribly wrong. If the car feels just as strong as it always has, then it's probably the dyno, IMO anyway.
Hey Jub,
I agree with ya'....the car feels fine and is idling @850rpm with no problems. Other Vettes dynoed at the same shop and their numbers were fine. Both w/Prochargers and at 650+rwhp, so I'm worried with my ride. I'll get her checked out for peace of mind and no hard driving until the dynotuning is complete.
Yeah, it's possible the original dyno wasn't calibrated correctly.... or who even knows.
If you are worried about the car losing power, take it back to the original shop and redyno it... Even if it was perhaps dynoing 'high', it would be somewhat of a relieve to know you hadn't lost all of that power.
... good luck
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2003 Z06 - 1.473 sixty foot , 383 Stroker NA, AFR 225's, Fast, Vararam, LG Longs, 390 Gear, thru stock mufflers. Pete Incaudo Street Cam, Full interior, stock suspension. All out of the box parts, no porting or tricks. 10.66 @ 129mph
Make sure the flywheel and Aussie cluch are balanced together. They generally are, but ask. ALSO, tell the installer to use RED locktight and put it IN the thread holes ALONG with ON the bolt threads. Use ARP bolts and check torque twice. LISTEN TO ME GRASSHOPPER, SAID THE OLD MAN
I would put in a bottle of techron fuel injector cleaner into the gas tank..
Sometimes you need it otherwise the car pulls timing..
my car was running a bit weak...although the idle was fine..and it ended up to be a cracked valve spring.
I had the double springs @ 23K miles and brought it to a couple of techs/tuners and it wasn't untll; the vette doctors dyno'd it that they suggested it was a bad valve spring..
Sure enough...one of the outer valve springs were fractured..
Cost me hp..
How long has it been since your heads were installed? Maybe your valve springs are growing weak...(after 20K miles replace without question) Cheap if you do it before they break)
I'm sure its the gas...or some carbon buildup...but just mentioning the mileage on the valvesprings as something to keep in mind..
As they weaken they do tend to float...which is not as noticable as you would think....but on a dyno it tends to show up as lost power..
Good luck and I'm sure its probably nothing but the dyno......
but you asked so I thought I'd throw out a few possibilities.
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The motor feels fine...no codes. I use only Chevron 93 octane fuel and I don't think I had any bad gas in the tank.
I'm going to get back to my original tuner to see what (if anything) is wrong with my set up to cause such a hp/tq loss. What could possibly cause such a big loss in readings?????
sig by GR8 White
Z06 Fest member III, IV, V, VI, VII, and Winterfests 1&2. new times coming soon! 
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