Bob K
Enthusiast
Just curious to know if anyone has dynoed their SRT/10 and what kind of numbers they produced.
Bob K
Bob K
Dyno numbers on SRT/10 ??
- Thread starter Bob K
- Start date
CajunViper
Enthusiast
Mine was at 447 rwhp and 490 ftlbs
I think there was another Houston SRT10 that went 445 and 483
respectively.
Dean
I think there was another Houston SRT10 that went 445 and 483
respectively.
Dean
John Myrick
Enthusiast
Dean is correct. My SRT-10 put 445 hp and 483 tq (SAE corrected) to the wheels.
Craig 201 MPH
Enthusiast
Motortrend did dyno a pre-production car but did not list teh numbers it produced.
Viperfreak2
Enthusiast
In the SRT book I just got it listed the horsepower as 501. Where'd the extra pony come from??? Only one?
I'm guessing the dyno numbers are rear wheel hp not at the flywheel per the factory specs. If you ad the average loss from the flywheel to rear tires, I'm guessing it would be close to the 500 if not more. Am I wrong on this one?
Absolutely correct Jerry:
Maybe someone can confirm this:
Dyno numbers that us "common folk" are able to obtain are usually done with the engine IN the car... with the numbers being determined as RWHP (rear wheel Horsepower).
Driveline loss has to then be factored in (RWHP / DL = HP)
So, 447 RWHP / DL (which is still to be determined) would = Crank Horsepower.
Using 12% driveline loss as the minimum (might be 13 or 14) here's the equation:
447 / .88 = 507!
Maybe someone can confirm this:
Dyno numbers that us "common folk" are able to obtain are usually done with the engine IN the car... with the numbers being determined as RWHP (rear wheel Horsepower).
Driveline loss has to then be factored in (RWHP / DL = HP)
So, 447 RWHP / DL (which is still to be determined) would = Crank Horsepower.
Using 12% driveline loss as the minimum (might be 13 or 14) here's the equation:
447 / .88 = 507!
Bwright
Enthusiast
Motor Trend used a Mustang brake dynamometer and got a peak torque reading of 482 lb.-ft at 3700 rpm. As per normal for a load-based chassis dyno this was measured at the wheels and I believe driveline loss was factored in. The results were corrected as per normal to SAE J1349 (weather correction).
treynor
Enthusiast
Give it up, Jerry. What did yours dyno (SAE & actual) and when did you dyno it?
Snakester
Enthusiast
Jerry,
All dyno runs are done in 4th gear, 5th would give poor results.
There has been a pretty big variance between different GenII Viper dyno results over the years.
Up to 50HP on the early models and as much as 30HP difference between different "cream puff" Vipers.
Also depending on break-in, dyno setup, and engine tune, added modifications would show different gains.
With the early GTSs making huge HP gains with simple mods, which had a much lessor affect on later cars with milder cams.
As long as you are getting at least 435RWHP, you car should be in the ballpark of 500 crank HP and the other SRT-10's.
If not, it may be running poorly and need to be tuned up.
-Dean.
All dyno runs are done in 4th gear, 5th would give poor results.
There has been a pretty big variance between different GenII Viper dyno results over the years.
Up to 50HP on the early models and as much as 30HP difference between different "cream puff" Vipers.
Also depending on break-in, dyno setup, and engine tune, added modifications would show different gains.
With the early GTSs making huge HP gains with simple mods, which had a much lessor affect on later cars with milder cams.
As long as you are getting at least 435RWHP, you car should be in the ballpark of 500 crank HP and the other SRT-10's.
If not, it may be running poorly and need to be tuned up.
-Dean.
Russ M
Enthusiast
Sir Fang,
So what was your dyno pull result?
Just curious since we know the cars make approximately the same power, this will just give us a feeling of how the dyno jet varies. My original estimate for SRT's was from 420-445 at the wheels. Would yours be in the 420 range?
So what was your dyno pull result?
Just curious since we know the cars make approximately the same power, this will just give us a feeling of how the dyno jet varies. My original estimate for SRT's was from 420-445 at the wheels. Would yours be in the 420 range?
Well, they ran it up 3 times and counted the last one. I do not know the first two results. I have asked for more info but have not received it yet.
The last one was 418. Could this be the first 2003 creampuff or maybe an error in the run? They are more concerned with what the change will be from the before mods and after mods dyno run so I'm guessing they would have wanted the lowest of the 3 runs to help their cause. I, on the other hand wanted the highest or at least the average.
I will keep you posted as new info comes my way...
They will have my new ride for 2 to 4 weeks. Not easy to part with after only 2 weeks of bonding.
The last one was 418. Could this be the first 2003 creampuff or maybe an error in the run? They are more concerned with what the change will be from the before mods and after mods dyno run so I'm guessing they would have wanted the lowest of the 3 runs to help their cause. I, on the other hand wanted the highest or at least the average.
I will keep you posted as new info comes my way...
They will have my new ride for 2 to 4 weeks. Not easy to part with after only 2 weeks of bonding.
2charmed
Enthusiast
Jerry,
They who? What are you having done?
2Charmed
They who? What are you having done?
2Charmed
Russ M
Enthusiast
Sir Fang,
Interesting, 418 is a bit bellow what I expected but then again dyno jet variance is a fact. I have seen several people who pulled those amazing 425 hp figures for early Gen 2 cars get a bit bent out of shape when they pulled 401 at another shop and realized that its just a dyno calibration error.
Does your dyno facility just do dyno work or is this the shop modifying your car as well? If so, then you may want to consider that they may be giving you lower numbers initially to make their work performed exaggerated.
Interesting, 418 is a bit bellow what I expected but then again dyno jet variance is a fact. I have seen several people who pulled those amazing 425
hp figures for early Gen 2 cars get a bit bent out of shape when they pulled 401 at another shop and realized that its just a dyno calibration error.Does your dyno facility just do dyno work or is this the shop modifying your car as well? If so, then you may want to consider that they may be giving you lower numbers initially to make their work performed exaggerated.
Paolo Castellano
Enthusiast
Well, they ran it up 3 times and counted the last one. I do not know the first two results. I have asked for more info but have not received it yet.
The last one was 418. Could this be the first 2003 creampuff or maybe an error in the run? They are more concerned with what the change will be from the before mods and after mods dyno run so I'm guessing they would have wanted the lowest of the 3 runs to help their cause. I, on the other hand wanted the highest or at least the average.
I will keep you posted as new info comes my way...
They will have my new ride for 2 to 4 weeks. Not easy to part with after only 2 weeks of bonding.
Jerry, dont worry, just go to a different dyno and if the results are similar, then you know what you have got! Otherwise, take it with a grain of salt. Paolo
Hang in there Jerry, as probably error on the run, but just as likely way too early to really do a dyno run. We have seen over the years many customers
run their car on a dyno with 1000 miles or under. The motor is so tight, it would be rare that one was truly broken in by then. This bears fruit in the
numerous calls we get from many who dyno again at 4-6K and have had a miraculous improvement in their hp/torque figures.
run their car on a dyno with 1000 miles or under. The motor is so tight, it would be rare that one was truly broken in by then. This bears fruit in the
numerous calls we get from many who dyno again at 4-6K and have had a miraculous improvement in their hp/torque figures.
Paolo Castellano
Enthusiast
Jerry, Bill is right, most cars will gain 10-20 RWHP by the time they get to 10,000-12,000 miles. The 1997 GTSthat went 192.6 MPH in Motor Trend has 11,000+ on the clock.
Bill and Paolo... those were my thoughts also. My SRT-10 is currently at an aftermarket exhaust and header shop being used as their prototype for the design and development of a new system that they will begin marketing when they are finished with my system. They are in the design stage now and should have the exhaust close to complete within 2 weeks and maybe another week or so for the header package. My guess is they wanted the lower number to make the after mods dyno run look better.
It was very interesting looking at the car with the side exhaust covers off to see what was done with the stock exhaust. When the photo system is uploaded on the new site I will post some photos.
It was very interesting looking at the car with the side exhaust covers off to see what was done with the stock exhaust. When the photo system is uploaded on the new site I will post some photos.
Just a thought.....
...OK, so the exhaust shop will use this 418 as their baseline and come up with a miraculous HP increase of 60 HP! Any relationship between the dyno shop and the exhaust shop?
You sure the Dyno shop wasn't ... ahem .... keepin' the numbers low for comparison purposes?
...OK, so the exhaust shop will use this 418 as their baseline and come up with a miraculous HP increase of 60 HP! Any relationship between the dyno shop and the exhaust shop?
You sure the Dyno shop wasn't ... ahem .... keepin' the numbers low for comparison purposes?
CajunViper
Enthusiast
TNT Motorsports has headers and exhaust already done. We will be dynoing it this weekend. They are taking orders now. There may be some special's for the first one's.
Dean
Dean
John Myrick
Enthusiast
My car had ~250 miles on it when dynoed. As stated above, the numbers were 445 HP and 483 tq (SAE corrected) to the wheels. From my personal experience, the rear wheel horsepower of my cars has not increased with additional miles. I also have other friends who have done multiple dyno's at various mileage and did not see any appreciable difference in output. Although this is a touchy subject... I will also add that the dyno operator mentioned that his expereince (typically with GM LS1/6 cars) has shown that the cars that were driven hard initially (ignoring the factory break-in procedure) have delivered the highest dyno readings. I'm not suggesting anyone ignore the factory break-in procedure. I am just repeating what I was told has been observed.
Jerry,
Did they do the dyno run? ... or did you go to an independent Dyno shop on your own?
I just don't see those numbers being within the "standard deviation from the mean".
May I suggest you recommend a third party test your car (after they make their mule set), with the system on..... and then off .... and report on the results? (I'm not insinuating anything, I just think their benchmark test didn't conform to what everyone has been reporting, therefore any performance gains or losses may not be credible).
Did they do the dyno run? ... or did you go to an independent Dyno shop on your own?
I just don't see those numbers being within the "standard deviation from the mean".
May I suggest you recommend a third party test your car (after they make their mule set), with the system on..... and then off .... and report on the results? (I'm not insinuating anything, I just think their benchmark test didn't conform to what everyone has been reporting, therefore any performance gains or losses may not be credible).
Mike Brunton
Enthusiast
I know some (cough "Russ") thinks that there is a "standard dyno variance" that could account for this, but that simply is not true. There is not an error in the dyno that could account for a car being this far off.
What CAN happen is that the operators can either fudge the numbers by faking conditions (make the air temp reading high - like put the sensor somewhere warmer than ambient and the corrected numbers come out much higher). Or you can fake low - dyno in a warm heated shop but have the sensor outside. It can also be plain ignorance or misinformed techs... they can run in something other than 4th, etc, etc, etc. Finally, there are temporary factors that affect dyno results - like the temperature of the engine (can affect it EASILY 20hp or more!), state of tune, etc. And of course the wear on the engine affects the dyno number - a broken in engine will dyno higher!
Dynos are relatively accurate machines. There should be an inherent error of much less than 1% - the sensors used to test are pretty accurate instruments.
It's all the OTHER stuff that causes the variance - NOT the dyno itself. Dynojet will back this up with more hard data than you can shake a stick at, so Russ before you claim I am wrong, check the facts.
As for your car Jerry, it is too low to be "dyno error". I submit that one of the following is the reason (NOT in order of likelihood):
1) DC had problems with CA cars and had to make some adjustments (to the computer program?) which killed off some HP
2) Your car was dynoed by someone who either didn't know how to accurately test it, or who had some incentive to "help" the numbers to be a bit low. All you gotta do is not give it 100% throttle or test it when it's hot, and you can easily slice off 20-30hp from the real reading.
3) There is something wrong with your car
I do NOT think it's simply that your car was not broken in enough - after all we have at least 2 other dynoes that are 30hp higher from cars with similar mileage. 30hp ain't gonna happen in a standard distribution of results... and if it did, I'd expect the LOW end to be 435 or 440 or so, to ensure DC is giving everyone the 500hp they expect. Even then, Sean Roe tested the driveline to be 11% or so, which is gonna take 445 to the wheels to conclude 500 at the crank.
Jerry, the next steps are simple, providing you want verification of this (and I would strongly suggest you should want that, if for no other reason than if there is something wrong with the car, you want to know about it and not have it "made better" by an exhaust). You need to get that car to another dyno - DON'T mention your prior results. See what they come up with. Ensure the car has had at least an hour to cool down before you dyno it, and ensure it's done in 4th gear and that there is nothing stuck behind the gas pedal. If you feel up for it, do 4 or 5 runs and watch the temp climb each run and the power drop off as it gets too hot. Then you have your "Jerry's max HP from his SRT" number, which you can cross-reference with your previous numbers.
If this second test bears out a sub 430 number (or worse, a sub-420 number) then get thee on the phone to DC and ask ***!
And finally, don't feel bad about the numbers... they are anyone's fault but yours. I am 90% confident that a second test at a totally different shop will give totally different numbers.
What CAN happen is that the operators can either fudge the numbers by faking conditions (make the air temp reading high - like put the sensor somewhere warmer than ambient and the corrected numbers come out much higher). Or you can fake low - dyno in a warm heated shop but have the sensor outside. It can also be plain ignorance or misinformed techs... they can run in something other than 4th, etc, etc, etc. Finally, there are temporary factors that affect dyno results - like the temperature of the engine (can affect it EASILY 20hp or more!), state of tune, etc. And of course the wear on the engine affects the dyno number - a broken in engine will dyno higher!
Dynos are relatively accurate machines. There should be an inherent error of much less than 1% - the sensors used to test are pretty accurate instruments.
It's all the OTHER stuff that causes the variance - NOT the dyno itself. Dynojet will back this up with more hard data than you can shake a stick at, so Russ before you claim I am wrong, check the facts.
As for your car Jerry, it is too low to be "dyno error". I submit that one of the following is the reason (NOT in order of likelihood):
1) DC had problems with CA cars and had to make some adjustments (to the computer program?) which killed off some HP
2) Your car was dynoed by someone who either didn't know how to accurately test it, or who had some incentive to "help" the numbers to be a bit low. All you gotta do is not give it 100% throttle or test it when it's hot, and you can easily slice off 20-30hp from the real reading.
3) There is something wrong with your car
I do NOT think it's simply that your car was not broken in enough - after all we have at least 2 other dynoes that are 30hp higher from cars with similar mileage. 30hp ain't gonna happen in a standard distribution of results... and if it did, I'd expect the LOW end to be 435 or 440 or so, to ensure DC is giving everyone the 500hp they expect. Even then, Sean Roe tested the driveline to be 11% or so, which is gonna take 445 to the wheels to conclude 500 at the crank.
Jerry, the next steps are simple, providing you want verification of this (and I would strongly suggest you should want that, if for no other reason than if there is something wrong with the car, you want to know about it and not have it "made better" by an exhaust). You need to get that car to another dyno - DON'T mention your prior results. See what they come up with. Ensure the car has had at least an hour to cool down before you dyno it, and ensure it's done in 4th gear and that there is nothing stuck behind the gas pedal. If you feel up for it, do 4 or 5 runs and watch the temp climb each run and the power drop off as it gets too hot. Then you have your "Jerry's max HP from his SRT" number, which you can cross-reference with your previous numbers.
If this second test bears out a sub 430 number (or worse, a sub-420 number) then get thee on the phone to DC and ask ***!
And finally, don't feel bad about the numbers... they are anyone's fault but yours. I am 90% confident that a second test at a totally different shop will give totally different numbers.
first, i'd ask what the 3 dyno runs were and post them here.
i've seen dyno numbers get higher when done consecutively. i've also seen dyno numbers decrease when done consecutively. so to say they took the last and assume it the lowest without asking means nothing.
also, to speculate that they 'chose' the lowest instead of the highest or the one that fell in the middle to justify the low numbers is a disservice to the company that is doing the work on your car. i hate to be that company and read that people are thinking that they are low-balling the numbers before the product is out.
second, try another dyno if it really bothers you.
one explanation is the variances from dyno to dyno.
another is that the engine has a few more ponies in her and needs more breaking in.
another is that you have a slow engine from the factory... it happens.
IMO, the real proof are the numbers at the track and not a dyno.
enjoy your ride and i look forward to reading the results of your mods.
don
i've seen dyno numbers get higher when done consecutively. i've also seen dyno numbers decrease when done consecutively. so to say they took the last and assume it the lowest without asking means nothing.
also, to speculate that they 'chose' the lowest instead of the highest or the one that fell in the middle to justify the low numbers is a disservice to the company that is doing the work on your car. i hate to be that company and read that people are thinking that they are low-balling the numbers before the product is out.
second, try another dyno if it really bothers you.
one explanation is the variances from dyno to dyno.
another is that the engine has a few more ponies in her and needs more breaking in.
another is that you have a slow engine from the factory... it happens.
IMO, the real proof are the numbers at the track and not a dyno.
enjoy your ride and i look forward to reading the results of your mods.
don
I have asked them for all of the information you mentioned above. I am not saying they did anything wrong. I have used their exhaust on my last 3 Vipers. I trust them and feel they are a very respected company and know what they are doing. I meant to say say some companies would like the before numbers to be lower to make the end numbers look better. What I typed in the above post was not what I meant to say.
The company has been great to work with. Heck, I'm trusting them with my 2 week old Viper. The owner is a super person as are his family and staff. I just thought it was strange for my number to be so much lower than the others. I didn't mean to say they were trying to cheat me. I guess what I was trying to say is the difference between the before and after is more important than the total hp. I am not an expert by any means when it comes to hp, dyno etc. That's why I was asking if this was normal to see such a difference between 3 cars.
The company has been great to work with. Heck, I'm trusting them with my 2 week old Viper. The owner is a super person as are his family and staff. I just thought it was strange for my number to be so much lower than the others. I didn't mean to say they were trying to cheat me. I guess what I was trying to say is the difference between the before and after is more important than the total hp. I am not an expert by any means when it comes to hp, dyno etc. That's why I was asking if this was normal to see such a difference between 3 cars.
Herman Buehrle
Enthusiast
Before you had modifications done, if the numbers concerned you, and if it's not to late, get your Viper to a dealer so they can check the computer and sensors. Last summer we had a member dyno very low, and he took his Viper to a dealer who checked everything out. They found a bad sensor, if I remember. Even though he had no check engine light.
Russ M
Enthusiast
Mike,
My comments regarding Dyno facilities fluctuating was right on, and I basically said the same thing you did. The only difference is that I left the part about the operator inflating/reducing results for their own purposes. I agree with you that this is the only reason why dyno results would vary, but my goal was not to point any fingers.
Sir Fang,
I hope your car comes out working very well, and that the dyno results show much improved numbers after the mods. I just hope that the exhaust company you are referring to is not Corsa, cause then I would understand where the claimed 18hp on Gen 2 creampuff vipers was attained.
My comments regarding Dyno facilities fluctuating was right on, and I basically said the same thing you did. The only difference is that I left the part about the operator inflating/reducing results for their own purposes. I agree with you that this is the only reason why dyno results would vary, but my goal was not to point any fingers.
Sir Fang,
I hope your car comes out working very well, and that the dyno results show much improved numbers after the mods. I just hope that the exhaust company you are referring to is not Corsa, cause then I would understand where the claimed 18hp on Gen 2 creampuff vipers was attained.
Mike Brunton
Enthusiast
Russ,
So does this mean you forgive me for the time I didn't include the RT/10 when I was talking about track Vipers?
I agree with you - it takes a skilled and knowledgeable dyno operator to remove as many variances as possible, so that the measured result can have as much inaccuracy removed as the equipment allows.
Jerry,
You have a good point - the DIFFERENCE matters more than the absolute numbers, however the reason everyone is raising eyebrows is that 418 sounds awfully low, and if your car seems to be running fine, then it would make us think there was a dyno problem (most likely in the operation of the dyno). Given that, can you be sure the exact same problem will be replicated exactly on your next time out? The 'corrected' numbers only correct to SAE based on your actual numbers - so if the correction factor is off (most likely scenario), then you would need it to be off the same amount next time.
Speaking of which - what were your UNcorrected numbers? What sort of weather was it when you dynoed?
So does this mean you forgive me for the time I didn't include the RT/10 when I was talking about track Vipers?
I agree with you - it takes a skilled and knowledgeable dyno operator to remove as many variances as possible, so that the measured result can have as much inaccuracy removed as the equipment allows.
Jerry,
You have a good point - the DIFFERENCE matters more than the absolute numbers, however the reason everyone is raising eyebrows is that 418 sounds awfully low, and if your car seems to be running fine, then it would make us think there was a dyno problem (most likely in the operation of the dyno). Given that, can you be sure the exact same problem will be replicated exactly on your next time out? The 'corrected' numbers only correct to SAE based on your actual numbers - so if the correction factor is off (most likely scenario), then you would need it to be off the same amount next time.
Speaking of which - what were your UNcorrected numbers? What sort of weather was it when you dynoed?
