Stock RWHP?
Thread Starter
Instructor
Joined: Mar 2003
Posts: 141
Likes: 0
From: Tacoma Washington
Stock RWHP?
HI,
I put my "mostly" stock 98 (6 spd) on the dyno last week at a local dyno competition just to see what it would do.
My 1999 TransAm (LS1/automatic) was rated at 325hp and dyno'd at 270rwhp so I estimated my vette at around 290 or 295.
Imagine my happy surprise when it dyno'd at 321rwhp / 325 torque
The only changes to the car are a SLP "power flo" cat-back exhaust and a blackwing air filter - I can't imagine they added that much. SO...
1) What are the average numbers for a stock 98?
2) Also, what is the "average" % of HP loss between the flywheel and rear wheels?
Oh yea, I took 2nd - 70hp behind a highly modified Pro-street dodge truck. Good thing the C6 Z06 declined to run his
Lanna
I put my "mostly" stock 98 (6 spd) on the dyno last week at a local dyno competition just to see what it would do.
My 1999 TransAm (LS1/automatic) was rated at 325hp and dyno'd at 270rwhp so I estimated my vette at around 290 or 295.
Imagine my happy surprise when it dyno'd at 321rwhp / 325 torque
The only changes to the car are a SLP "power flo" cat-back exhaust and a blackwing air filter - I can't imagine they added that much. SO...
1) What are the average numbers for a stock 98?
2) Also, what is the "average" % of HP loss between the flywheel and rear wheels?
Oh yea, I took 2nd - 70hp behind a highly modified Pro-street dodge truck. Good thing the C6 Z06 declined to run his
Lanna
Melting Slicks
Joined: May 2007
Posts: 2,533
Likes: 1
From: North Aurora IL
Not bad numbers....dyno to dyno they all vary....so for a true ready if you could dyno the same 2 cars and you will see the difference there......if you take it to another dyno your read out will be different
Le Mans Master
Joined: Dec 2005
Posts: 8,475
Likes: 332
From: Port Arthur, Texas 77642
Before extensive mods, my 99 MN6 with B&B catback, K&N, opened up oem airbox, no cats, Hypertech tune and O2 simulators = 337rwhp,338rwtq 
the tuner said that was the highest he'd ever seen with so few mods and "tune in a can"
the tuner said that was the highest he'd ever seen with so few mods and "tune in a can"
Last edited by NemesisC5; Sep 22, 2007 at 04:54 PM.
Safety Car
Joined: Oct 2004
Posts: 4,816
Likes: 132
From: Plano TX
dynos vary.. some shops use uncorrected numbers, some don't.. makes a BIG difference in results.. More than likely the previous owner had a dyno tune done.. Those numbers look normal for a tuned mn6 and blackwing.. Cat backs do nothing for rwhp other than sound
Le Mans Master
Joined: Dec 2005
Posts: 8,475
Likes: 332
From: Port Arthur, Texas 77642
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Le Mans Master
Joined: Aug 2005
Posts: 5,130
Likes: 3
From: Winter Park FL
15% drivetrain loss on a 345hp car means 293rwhp as opposed to 12% which means 303rwhp. Since 6 speeds dyno around 300-310 it puts them around 10-12% loss. This is on a Dynojet of course. If you are refering to a mustang dyno they will eat up a little more power.
Drifting
Joined: Jun 2002
Posts: 1,847
Likes: 1
From: Iowa
Cruise-In IV Veteran
Cruise-In V Veteran
Le Mans Master
Joined: Aug 2005
Posts: 5,130
Likes: 3
From: Winter Park FL
Because they are machines and might not all be calibrated correctly. They can also be influenced by the parameters that the operators put in. There are plenty of "tricks" you can play to influence dynos as well as other factors. They are as standardized and accurate as they can be but will never be 100% accurate and consistent.
Thread Starter
Instructor
Joined: Mar 2003
Posts: 141
Likes: 0
From: Tacoma Washington
HI,
The equipment they use is a Dynojet Winpep 7 performance evaluation program. I know there can be variences between the different makes of dynos and if/how they compensate for atmospheric conditions - so I'm not taking the readings as a definate.. I was just happy that my "mostly stock" vette out HP'd all but 2 of the "heavily modified" vehicles that dyno'd that night
Someone mentioned that the numbers sound like a C5 with a "tune" on it. I'm not sure if he/she was refering to my car or one of the posts after mine - but I'm pretty sure the program is stock.
I was having some issues with pinging so I took it to a local Corvette shop. Well, long story short - they weren't used to working on newer vettes and screwed up the programming so bad that even the help desk for their programming software couldn't tell what they'd done. I ended up taking it to the dealership and having the stock programming put back on it. It hasn't been re-programmed since.
As for the pinging - I got ambitious one weekend and replaced the fuel filter and that seems to have taken care of the problem.
Lanna
The equipment they use is a Dynojet Winpep 7 performance evaluation program. I know there can be variences between the different makes of dynos and if/how they compensate for atmospheric conditions - so I'm not taking the readings as a definate.. I was just happy that my "mostly stock" vette out HP'd all but 2 of the "heavily modified" vehicles that dyno'd that night
Someone mentioned that the numbers sound like a C5 with a "tune" on it. I'm not sure if he/she was refering to my car or one of the posts after mine - but I'm pretty sure the program is stock.
I was having some issues with pinging so I took it to a local Corvette shop. Well, long story short - they weren't used to working on newer vettes and screwed up the programming so bad that even the help desk for their programming software couldn't tell what they'd done. I ended up taking it to the dealership and having the stock programming put back on it. It hasn't been re-programmed since.
As for the pinging - I got ambitious one weekend and replaced the fuel filter and that seems to have taken care of the problem.
Lanna
Drifting
Joined: Jun 2002
Posts: 1,847
Likes: 1
From: Iowa
Cruise-In IV Veteran
Cruise-In V Veteran
HI,
The equipment they use is a Dynojet Winpep 7 performance evaluation program. I know there can be variences between the different makes of dynos and if/how they compensate for atmospheric conditions - so I'm not taking the readings as a definate.. I was just happy that my "mostly stock" vette out HP'd all but 2 of the "heavily modified" vehicles that dyno'd that night
I was having some issues with pinging...I got ambitious one weekend and replaced the fuel filter and that seems to have taken care of the problem.
Lanna
The equipment they use is a Dynojet Winpep 7 performance evaluation program. I know there can be variences between the different makes of dynos and if/how they compensate for atmospheric conditions - so I'm not taking the readings as a definate.. I was just happy that my "mostly stock" vette out HP'd all but 2 of the "heavily modified" vehicles that dyno'd that night
I was having some issues with pinging...I got ambitious one weekend and replaced the fuel filter and that seems to have taken care of the problem.
Lanna
Mine suffered from "pinging" problems too, and I finally got it to stop by having the computer professionally retuned.
The dealer said it was "normal" for it to ping.
As far as your dyno numbers, I don't really know what to think of what some of these dynos put out. Personally, I figure it's just a guessing game which someone should not put a whole lot of faith and credibility into.
A dyno is maybe a good tool for indicating how much of a difference some mods caused.....but even then, those figures can differ from one day to the next, even on the same dyno.
Advanced
Joined: May 2006
Posts: 73
Likes: 0
From: Michigan City Indiana
I recently had my 99 coupe tuned at Mid-America's funfest. The car is stock with only a Magnaflow exhaust. My baseline was 299.8. After the tune it was 313.4HP and 323.6 torque with 40,000 miles. My uncles 2005 coupe was only on the dyno for a baseline. His was 356.3.
Some of those other numbers sound a little exaggerated. What is basically stock? Not trying to cause trouble. It is what it is I guess. Wish I had turned those numbers.
Some of those other numbers sound a little exaggerated. What is basically stock? Not trying to cause trouble. It is what it is I guess. Wish I had turned those numbers.
Last edited by sebesta1990; Oct 7, 2007 at 08:53 PM. Reason: Forgot something
Advanced
Joined: May 2006
Posts: 73
Likes: 0
From: Michigan City Indiana
HI,
I put my "mostly" stock 98 (6 spd) on the dyno last week at a local dyno competition just to see what it would do.
My 1999 TransAm (LS1/automatic) was rated at 325hp and dyno'd at 270rwhp so I estimated my vette at around 290 or 295.
Imagine my happy surprise when it dyno'd at 321rwhp / 325 torque
The only changes to the car are a SLP "power flo" cat-back exhaust and a blackwing air filter - I can't imagine they added that much. SO...
1) What are the average numbers for a stock 98?
2) Also, what is the "average" % of HP loss between the flywheel and rear wheels?
Oh yea, I took 2nd - 70hp behind a highly modified Pro-street dodge truck. Good thing the C6 Z06 declined to run his
Lanna
I put my "mostly" stock 98 (6 spd) on the dyno last week at a local dyno competition just to see what it would do.
My 1999 TransAm (LS1/automatic) was rated at 325hp and dyno'd at 270rwhp so I estimated my vette at around 290 or 295.
Imagine my happy surprise when it dyno'd at 321rwhp / 325 torque
The only changes to the car are a SLP "power flo" cat-back exhaust and a blackwing air filter - I can't imagine they added that much. SO...
1) What are the average numbers for a stock 98?
2) Also, what is the "average" % of HP loss between the flywheel and rear wheels?
Oh yea, I took 2nd - 70hp behind a highly modified Pro-street dodge truck. Good thing the C6 Z06 declined to run his
Lanna
