HP Woes
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,075
Likes: 19
From: Mississauga Ontario
HP Woes
Hi There,
I was hoping someone on the forum could help me out. I recently purchased a 1997 C-5 (automatic). To increase it's performance, I have done the following:
- Dynatech headers & hi-flow cats
- B & B cat back exhaust
- Yank 3800 stall
- 3.42 gears
- ATI Procharger (7 psi)
- Granatelli mass air flow sensor
- BBK 80mm Throttle Body
- Weiand Lingenfelter manifold
- LS1 Edit
I have had the car dynoed on a Dynojet. It produces 427RWHP and 467Ft/LB of torque. I have read articles on the supercharger, so I know what others have experienced. I also know what the manufacturer claims. I am quite happy with the torque results, but I figured I should have been somewhere around 450RWHP with only the S/C and without any other mods. With the additional mods, I would have expected to see higher numbers.
Does anyone agree or am I just crazy??? Any insight/thoughts would be greatly appreciated.
Thanks,
LS12NV
I was hoping someone on the forum could help me out. I recently purchased a 1997 C-5 (automatic). To increase it's performance, I have done the following:
- Dynatech headers & hi-flow cats
- B & B cat back exhaust
- Yank 3800 stall
- 3.42 gears
- ATI Procharger (7 psi)
- Granatelli mass air flow sensor
- BBK 80mm Throttle Body
- Weiand Lingenfelter manifold
- LS1 Edit
I have had the car dynoed on a Dynojet. It produces 427RWHP and 467Ft/LB of torque. I have read articles on the supercharger, so I know what others have experienced. I also know what the manufacturer claims. I am quite happy with the torque results, but I figured I should have been somewhere around 450RWHP with only the S/C and without any other mods. With the additional mods, I would have expected to see higher numbers.
Does anyone agree or am I just crazy??? Any insight/thoughts would be greatly appreciated.
Thanks,
LS12NV
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,075
Likes: 19
From: Mississauga Ontario
Thanks for you input. Unfortunately, I did not perform baseline testing before the mods. What I do know is that my best 0-60 time prior to the mods was 4.97 seconds. Now, the best I can do is 4.47 seconds due to severe traction issues. I can't keep the tires from spinning at launch. Even cruising at 20-30 mph, if I stomp on the gas, the back end jiggles as the tires are hooking up - I have to be very careful where I decide to open the car up. May have to look into bigger rubber - that's a whole other issue with the car...
Regards,
LS12NV
Regards,
LS12NV
Team Owner
Joined: Dec 1999
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Likes: 1,217
From: Here
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have you posted over here?? http://forums.corvetteforum.com/forumdisplay.php?f=86
might get more replies
might get more replies
Le Mans Master
Joined: Jul 2002
Posts: 7,370
Likes: 8
From: Slave to the evil empire
Cruise-In V Veteran
St. Jude Donor '04
Originally Posted by LS12NV
- Dynatech headers & hi-flow cats
- B & B cat back exhaust
- Yank 3800 stall
- 3.42 gears
- ATI Procharger (7 psi)
- Granatelli mass air flow sensor
- BBK 80mm Throttle Body
- Weiand Lingenfelter manifold
- LS1 Edit
- B & B cat back exhaust
- Yank 3800 stall
- 3.42 gears
- ATI Procharger (7 psi)
- Granatelli mass air flow sensor
- BBK 80mm Throttle Body
- Weiand Lingenfelter manifold
- LS1 Edit
I learned this with my Magnuson which has an aluminum manifold, driving down the freeway at 75 mph my IAT temps are right at 180* which is where my coolant and oil temps are running
Melting Slicks
Joined: Jun 2001
Posts: 2,743
Likes: 3
From: Davie Florida
I could be wrong but part of your low HP numbers problem might be the SS3800. That converter is really not designed for your application and you could be losing HP on the dyno because of it. Yank makes an SS3800E that is designed for use with forced induction applications. Also as mentioned above if your manifold is aluminum that could also be a problem.
Instructor
Joined: May 2001
Posts: 186
Likes: 0
From: Midwest
You possibly are right on for your HP expectations. I agree with the post conscerning the lack of a baseline, their can be a 5% difference from stock car to car. Different DynoJets can read differently and you most likely will need to custom tune your setup with something like LS1 Edit to optimise your combination, like the others potentially did. Interestingly, there is one DynoJet in our area that reads higher then other DynoJets, older version of WinPep or less smoothing of the line charts I would assume. Guess how far people are willing to drive to get tested on that one for good internet numbers, then we all try to match them. We have a Mustang dyno, so you know where that leaves us, however, we do most of the tuning around here and they do most of the testing, works for us.
EJ
EJ
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,075
Likes: 19
From: Mississauga Ontario
The Weiand manifold is aluminum. I have read about there being issues with aluminum manifolds retaining heat. I guess I should have the temparature checked out as suggested above. Is this a difficult thing to determine???
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Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,075
Likes: 19
From: Mississauga Ontario
I was not aware of the SS3800E. The guys at T Byrne Motorsport recommended the stall converter/gear combo based on my set-up. I'll have to investigate this further...
Thanks,
LS12NV
Thanks,
LS12NV
Team Owner
Joined: Aug 2003
Posts: 38,314
Likes: 35
Originally Posted by Mitch C
I could be wrong but part of your low HP numbers problem might be the SS3800. That converter is really not designed for your application and you could be losing HP on the dyno because of it.
Thats what I was thinking. Let us know what you find out.
Le Mans Master
Joined: Jul 2002
Posts: 7,370
Likes: 8
From: Slave to the evil empire
Cruise-In V Veteran
St. Jude Donor '04
Originally Posted by LS12NV
The Weiand manifold is aluminum. I have read about there being issues with aluminum manifolds retaining heat. I guess I should have the temparature checked out as suggested above. Is this a difficult thing to determine???
BTW - I agree with the converter and also don't forget changing gear ratios to the 3.42 will make your dyno numbers a little lower, this is why dyno numbers don't mean d**k
Melting Slicks
Joined: Jun 2001
Posts: 2,743
Likes: 3
From: Davie Florida
Originally Posted by LS12NV
Can you elaborate on why the gear change would affect the dyno results?
Last edited by Mitch C; Oct 17, 2004 at 11:39 PM.
Instructor
Joined: May 2001
Posts: 186
Likes: 0
From: Midwest
Originally Posted by Mitch C
I can't tell you exactly why but if you go to a numerically higher gear like 3.42 to 3.73 for example your dyno readings will be lower. Going from 3.42 to 3.73 your car will dyno about 8-10 RWHP less. You really doesn't lose horse power you just get a lower reading.
EJ