Disapointing Dyno (wheeze... wheeze)
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Why do you guys get so worked up about dyno numbers?? I have said it 100Xs that these dynos are NOT as accurate as most think.
COrk's 434 setup only made 395rwhp (10.2sec@131) and 85vett (11.2@121+) made only 30 hp less on one recently. I find it hard to beleive there is only 30hp difference between two cars that weight virtually idential, and run a full second apart!
Most recently, yesterday, I was at GMs St Catharines Engine facility in Canada. Got to watch a few LS6 corvette motors being run through the paces, and some high feature V6 motors which we make cam caps for. These were running these motors to the max, with the cam caps glowing red hot
The building is grossly impressive and I asked the Engineer I work with several times if I could please have a few aluminum blocks. They literally have them stacked 4 rows high, for about 4 yards wide, and 80 yards long. Just makes your mouth water looking at the potential HP that is sitting there. Connecting rods, and pistons, heads...oh too much for the eyes.
Anyways, I asked the dyno operator what he thought about repeatability of the motors. For instance if they put an engine on it, run it, and then run it again after hookin it up again. He said you would see about a 10% change run to run. At say 300hp that is ~30hp change. I said we have many discussions with regards to accuracy of these adn he said, well couple that 10% at the flywheel with drivetrain components and you will have a TON of variation...probably upwards of 30% or more. NOT LOSS, but variation. He laughed and said, we use these dynos for component failure anaylses and to troubleshoot problems. Most of the hp rating you see are theoretical that they advertise, while he did say, with the above margins the dynos usually put out in the ballpark of the estimate the engineers put forth.
At the end of the day, I think he is pretty much saying the same thing I am. Use these as a rough gage, not even sure I would say that. They are NOT an exact gage of performance. If you really believe they are, how is corky only making ~450fwhp and running bottom 10s and pushing a 3400# car through the traps at 131MPH? That dyno they were on was off at least 100+ hp.
Not really something I would place all my hard work, time and money on a gage of success and failure, and I think that is what some of you guys do, then your totally disappointed with the outcome. Not a very safe thing to do. 
COrk's 434 setup only made 395rwhp (10.2sec@131) and 85vett (11.2@121+) made only 30 hp less on one recently. I find it hard to beleive there is only 30hp difference between two cars that weight virtually idential, and run a full second apart!
Most recently, yesterday, I was at GMs St Catharines Engine facility in Canada. Got to watch a few LS6 corvette motors being run through the paces, and some high feature V6 motors which we make cam caps for. These were running these motors to the max, with the cam caps glowing red hot
The building is grossly impressive and I asked the Engineer I work with several times if I could please have a few aluminum blocks. They literally have them stacked 4 rows high, for about 4 yards wide, and 80 yards long. Just makes your mouth water looking at the potential HP that is sitting there. Connecting rods, and pistons, heads...oh too much for the eyes. Anyways, I asked the dyno operator what he thought about repeatability of the motors. For instance if they put an engine on it, run it, and then run it again after hookin it up again. He said you would see about a 10% change run to run. At say 300hp that is ~30hp change. I said we have many discussions with regards to accuracy of these adn he said, well couple that 10% at the flywheel with drivetrain components and you will have a TON of variation...probably upwards of 30% or more. NOT LOSS, but variation. He laughed and said, we use these dynos for component failure anaylses and to troubleshoot problems. Most of the hp rating you see are theoretical that they advertise, while he did say, with the above margins the dynos usually put out in the ballpark of the estimate the engineers put forth.
At the end of the day, I think he is pretty much saying the same thing I am. Use these as a rough gage, not even sure I would say that. They are NOT an exact gage of performance. If you really believe they are, how is corky only making ~450fwhp and running bottom 10s and pushing a 3400# car through the traps at 131MPH? That dyno they were on was off at least 100+ hp.
Not really something I would place all my hard work, time and money on a gage of success and failure, and I think that is what some of you guys do, then your totally disappointed with the outcome. Not a very safe thing to do.
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Why do you guys get so worked up about dyno numbers?? I have said it 100Xs that these dynos are NOT as accurate as most think.
COrk's 434 setup only made 395rwhp (10.2sec@131) and 85vett (11.2@121+) made only 30 hp less on one recently. I find it hard to beleive there is only 30hp difference between two cars that weight virtually idential, and run a full second apart!
Most recently, yesterday, I was at GMs St Catharines Engine facility in Canada. Got to watch a few LS6 corvette motors being run through the paces, and some high feature V6 motors which we make cam caps for. These were running these motors to the max, with the cam caps glowing red hot The building is grossly impressive and I asked the Engineer I work with several times if I could please have a few aluminum blocks. They literally have them stacked 4 rows high, for about 4 yards wide, and 80 yards long. Just makes your mouth water looking at the potential HP that is sitting there. Connecting rods, and pistons, heads...oh too much for the eyes.
Anyways, I asked the dyno operator what he thought about repeatability of the motors. For instance if they put an engine on it, run it, and then run it again after hookin it up again. He said you would see about a 10% change run to run. At say 300hp that is ~30hp change. I said we have many discussions with regards to accuracy of these adn he said, well couple that 10% at the flywheel with drivetrain components and you will have a TON of variation...probably upwards of 30% or more. NOT LOSS, but variation. He laughed and said, we use these dynos for component failure anaylses and to troubleshoot problems. Most of the hp rating you see are theoretical that they advertise, while he did say, with the above margins the dynos usually put out in the ballpark of the estimate the engineers put forth.
At the end of the day, I think he is pretty much saying the same thing I am. Use these as a rough gage, not even sure I would say that. They are NOT an exact gage of performance. If you really believe they are, how is corky only making ~450fwhp and running bottom 10s and pushing a 3400# car through the traps at 131MPH? That dyno they were on was off at least 100+ hp. Not really something I would place all my hard work, time and money on a gage of success and failure, and I think that is what some of you guys do, then your totally disappointed with the outcome. Not a very safe thing to do.
PS: corvette0096...where ever you have your picture hosted, take a TON of time to download, it often messes up the posting process I believe.
COrk's 434 setup only made 395rwhp (10.2sec@131) and 85vett (11.2@121+) made only 30 hp less on one recently. I find it hard to beleive there is only 30hp difference between two cars that weight virtually idential, and run a full second apart!
Most recently, yesterday, I was at GMs St Catharines Engine facility in Canada. Got to watch a few LS6 corvette motors being run through the paces, and some high feature V6 motors which we make cam caps for. These were running these motors to the max, with the cam caps glowing red hot
The building is grossly impressive and I asked the Engineer I work with several times if I could please have a few aluminum blocks. They literally have them stacked 4 rows high, for about 4 yards wide, and 80 yards long. Just makes your mouth water looking at the potential HP that is sitting there. Connecting rods, and pistons, heads...oh too much for the eyes. Anyways, I asked the dyno operator what he thought about repeatability of the motors. For instance if they put an engine on it, run it, and then run it again after hookin it up again. He said you would see about a 10% change run to run. At say 300hp that is ~30hp change. I said we have many discussions with regards to accuracy of these adn he said, well couple that 10% at the flywheel with drivetrain components and you will have a TON of variation...probably upwards of 30% or more. NOT LOSS, but variation. He laughed and said, we use these dynos for component failure anaylses and to troubleshoot problems. Most of the hp rating you see are theoretical that they advertise, while he did say, with the above margins the dynos usually put out in the ballpark of the estimate the engineers put forth.
At the end of the day, I think he is pretty much saying the same thing I am. Use these as a rough gage, not even sure I would say that. They are NOT an exact gage of performance. If you really believe they are, how is corky only making ~450fwhp and running bottom 10s and pushing a 3400# car through the traps at 131MPH? That dyno they were on was off at least 100+ hp.
Not really something I would place all my hard work, time and money on a gage of success and failure, and I think that is what some of you guys do, then your totally disappointed with the outcome. Not a very safe thing to do. PS: corvette0096...where ever you have your picture hosted, take a TON of time to download, it often messes up the posting process I believe.
Safety Car
Joined: Apr 2004
Posts: 4,532
Likes: 7
From: Lahaina Hi
I think you need to do some more home work and check the tune.
You said you had GM redo your computer I don't think that GM will take the time to get into your tables and flash the correct information to make the car run faster .
I would check your retard RD table and see what that is doing.
Flash some diff numbers to the computer.
GM if you check the flow stats on the exaust it is at the peek for your car and I can't see how headers and exaust will help just my o2.
On my 94 I did port the throttle body myself and changed air cleaners.
Added ram air ,Remember when you dyno a static vett the flow will never be their the car is standing still.
Explain why a vett with nitrous can turn great numbers and nothing more then oxygen is being added to the fuel
I run 11.20's and it is stock with 307's in the rear and only exaust cut outs when needed.
I would hit the 1/4 mile and see what the car will do before you spend any more money.
Your knock count could be way high if you are not using an LT4 knock sensor and that will slow the car down.
You said you had GM redo your computer I don't think that GM will take the time to get into your tables and flash the correct information to make the car run faster .
I would check your retard RD table and see what that is doing.
Flash some diff numbers to the computer.
GM if you check the flow stats on the exaust it is at the peek for your car and I can't see how headers and exaust will help just my o2.
On my 94 I did port the throttle body myself and changed air cleaners.
Added ram air ,Remember when you dyno a static vett the flow will never be their the car is standing still.
Explain why a vett with nitrous can turn great numbers and nothing more then oxygen is being added to the fuel
I run 11.20's and it is stock with 307's in the rear and only exaust cut outs when needed.
I would hit the 1/4 mile and see what the car will do before you spend any more money.
Your knock count could be way high if you are not using an LT4 knock sensor and that will slow the car down.
