Dyno tune power numbers seem too LOW???
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Junior Member
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From: Goldsboro, North Carolina
Dyno tune power numbers seem too LOW???
Hey Guys. What do you think? Don't these dyno tune numbers seem too LOW??
234 RWTorque / 184 RWHorse . I had my truck DYNO tuned with Diablo programmer at a performance shop in Raleigh. The thing is I just had my 2003 5.4V8 given a fresh set of stage 2 comp cams, equal length headers, custom true dual w/ prochamber mid section, high flow cats, 40 series flowmasters, and shielded cold air intake. Just thought for sure a truck that comes stock with crank 350 torque and 260 horse would be a little more than that, especially with good mods. I realize there is usually the 30-40% loss but still seems wrong. Thanks for any input. Hope my truck will still tow a 26ft RV weighing 4,400lbs through the mountains....
234 RWTorque / 184 RWHorse . I had my truck DYNO tuned with Diablo programmer at a performance shop in Raleigh. The thing is I just had my 2003 5.4V8 given a fresh set of stage 2 comp cams, equal length headers, custom true dual w/ prochamber mid section, high flow cats, 40 series flowmasters, and shielded cold air intake. Just thought for sure a truck that comes stock with crank 350 torque and 260 horse would be a little more than that, especially with good mods. I realize there is usually the 30-40% loss but still seems wrong. Thanks for any input. Hope my truck will still tow a 26ft RV weighing 4,400lbs through the mountains....
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From: Winder, GA
260 Crankshaft HP equates to 195 Rear Wheel HP, assuming a roughly 25% loss through the transmission and differential. Manual transmissions will see a bit less loss, maybe 19% so then you'd be at about 210 HP. But enough about drivetrain losses.
184 HP seems slightly low for a 2003 5.4L, regardless of transmission. The problem here is that dynos are a tool used to measure the differences between one modification and the next, not as the end-all-be-all of power output rating. Differences between dyno types (Inertia and Eddy Current), PAU (Power Absorption Unit) design, software, calibration, and even weather correction will play a significant part in your final output numbers. I'd honestly be surprised if you went down the road to a different dyno and saw the same numbers or power curves, even from the same model dyno.
The big question is, did the tuner do a before and after comparison of your vehicle with and without the modifications, or at least before and after tuning? That's pretty handy information to have and will go a long was to show that your results were an improvement over where you started. I know the dyno numbers you received appear disappointing, but does the truck feel any different from before you did the mods/tuning to afterwards? If you don't feel like the performance is there then you may need to have another look. If the truck feels spunky, then I wouldn't lose too much sleep over the dyno numbers.
One final thought... While cams and headers all sound good on paper, the reality is that they simply don't offer the performance gains every seems to think they will. In order to make more power, you need more air and fuel. The fact is that cams and exhaust will only improve scavenging and affect volumetric efficiency just so much, after which point the only way to get any more air into the engine is to go to forced induction (turbo/super charger). Even worse, many vehicles will see a significant loss in low to mid RPM torque due to the loss of backpressure. Certainly not ideal for a vehicle that would be used for towing. Again, only a before and after comparison would truly show whether there was a positive or negative change.
I know this isn't fantastic news, but I hope it helps answer your questions.
184 HP seems slightly low for a 2003 5.4L, regardless of transmission. The problem here is that dynos are a tool used to measure the differences between one modification and the next, not as the end-all-be-all of power output rating. Differences between dyno types (Inertia and Eddy Current), PAU (Power Absorption Unit) design, software, calibration, and even weather correction will play a significant part in your final output numbers. I'd honestly be surprised if you went down the road to a different dyno and saw the same numbers or power curves, even from the same model dyno.
The big question is, did the tuner do a before and after comparison of your vehicle with and without the modifications, or at least before and after tuning? That's pretty handy information to have and will go a long was to show that your results were an improvement over where you started. I know the dyno numbers you received appear disappointing, but does the truck feel any different from before you did the mods/tuning to afterwards? If you don't feel like the performance is there then you may need to have another look. If the truck feels spunky, then I wouldn't lose too much sleep over the dyno numbers.
One final thought... While cams and headers all sound good on paper, the reality is that they simply don't offer the performance gains every seems to think they will. In order to make more power, you need more air and fuel. The fact is that cams and exhaust will only improve scavenging and affect volumetric efficiency just so much, after which point the only way to get any more air into the engine is to go to forced induction (turbo/super charger). Even worse, many vehicles will see a significant loss in low to mid RPM torque due to the loss of backpressure. Certainly not ideal for a vehicle that would be used for towing. Again, only a before and after comparison would truly show whether there was a positive or negative change.
I know this isn't fantastic news, but I hope it helps answer your questions.
Last edited by ASEMechanic; Jun 12, 2011 at 09:32 PM.
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Junior Member
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From: Goldsboro, North Carolina
I think you may be right about the dyno situation. The dyno I used is out of performance shop that caters more towards small imports and don't usually see trucks. I do feel like my truck ran better before the dyno tune. However the truck had starting issues after initial cam install that are now since gone. So that is good.
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Joined: Apr 2009
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From: In the fast lane from LA to Tokyo...
260 Crankshaft HP equates to 195 Rear Wheel HP, assuming a roughly 25% loss through the transmission and differential. Manual transmissions will see a bit less loss, maybe 19% so then you'd be at about 210 HP. But enough about drivetrain losses.
184 HP seems slightly low for a 2003 5.4L, regardless of transmission. The problem here is that dynos are a tool used to measure the differences between one modification and the next, not as the end-all-be-all of power output rating. Differences between dyno types (Inertia and Eddy Current), PAU (Power Absorption Unit) design, software, calibration, and even weather correction will play a significant part in your final output numbers. I'd honestly be surprised if you went down the road to a different dyno and saw the same numbers or power curves, even from the same model dyno.
The big question is, did the tuner do a before and after comparison of your vehicle with and without the modifications, or at least before and after tuning? That's pretty handy information to have and will go a long was to show that your results were an improvement over where you started. I know the dyno numbers you received appear disappointing, but does the truck feel any different from before you did the mods/tuning to afterwards? If you don't feel like the performance is there then you may need to have another look. If the truck feels spunky, then I wouldn't lose too much sleep over the dyno numbers.
One final thought... While cams and headers all sound good on paper, the reality is that they simply don't offer the performance gains every seems to think they will. In order to make more power, you need more air and fuel. The fact is that cams and exhaust will only improve scavenging and affect volumetric efficiency just so much, after which point the only way to get any more air into the engine is to go to forced induction (turbo/super charger). Even worse, many vehicles will see a significant loss in low to mid RPM torque due to the loss of backpressure. Certainly not ideal for a vehicle that would be used for towing. Again, only a before and after comparison would truly show whether there was a positive or negative change.
I know this isn't fantastic news, but I hope it helps answer your questions.
184 HP seems slightly low for a 2003 5.4L, regardless of transmission. The problem here is that dynos are a tool used to measure the differences between one modification and the next, not as the end-all-be-all of power output rating. Differences between dyno types (Inertia and Eddy Current), PAU (Power Absorption Unit) design, software, calibration, and even weather correction will play a significant part in your final output numbers. I'd honestly be surprised if you went down the road to a different dyno and saw the same numbers or power curves, even from the same model dyno.
The big question is, did the tuner do a before and after comparison of your vehicle with and without the modifications, or at least before and after tuning? That's pretty handy information to have and will go a long was to show that your results were an improvement over where you started. I know the dyno numbers you received appear disappointing, but does the truck feel any different from before you did the mods/tuning to afterwards? If you don't feel like the performance is there then you may need to have another look. If the truck feels spunky, then I wouldn't lose too much sleep over the dyno numbers.
One final thought... While cams and headers all sound good on paper, the reality is that they simply don't offer the performance gains every seems to think they will. In order to make more power, you need more air and fuel. The fact is that cams and exhaust will only improve scavenging and affect volumetric efficiency just so much, after which point the only way to get any more air into the engine is to go to forced induction (turbo/super charger). Even worse, many vehicles will see a significant loss in low to mid RPM torque due to the loss of backpressure. Certainly not ideal for a vehicle that would be used for towing. Again, only a before and after comparison would truly show whether there was a positive or negative change.
I know this isn't fantastic news, but I hope it helps answer your questions.
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From: so fla
Did they actually create a custom tune using CMR, or just adjust the tune with the Predator?
ideally, a combo like that would need some quality time spent on idle and start up tuning, as well as part throttle. The WOT stuff would be the simple part.
ideally, a combo like that would need some quality time spent on idle and start up tuning, as well as part throttle. The WOT stuff would be the simple part.
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I watched the whole process. They pretty much took the tune the diablo programmer came with and adjusted the parameters. They used alot of my premium fuel too, opening it up a couple times and then going back tot he computer. So NO, I do not believe they wrote a custom tune. I think that would have been alot better and it just kind of hit me now when you asked that question. What do you recommend at this point? I paid 320 for the tune and like I said I'm not really satisfied other than the fix to the delayed starting which went away after adjustments made. I also mentioned I believe it ran better before getting on the dyno. Thanks.
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Former Sponsor
Joined: Jan 2010
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From: so fla
I watched the whole process. They pretty much took the tune the diablo programmer came with and adjusted the parameters. They used alot of my premium fuel too, opening it up a couple times and then going back tot he computer. So NO, I do not believe they wrote a custom tune. I think that would have been alot better and it just kind of hit me now when you asked that question. What do you recommend at this point? I paid 320 for the tune and like I said I'm not really satisfied other than the fix to the delayed starting which went away after adjustments made. I also mentioned I believe it ran better before getting on the dyno. Thanks.
Thanks