Dyno Dynamics Rollng Road ( Low Results )
#1
Dyno Dynamics Rollng Road ( Low Results )
Guys, need your help......
Link to results slip below, nowhere near what was expected need help if am reading wrong or need to try a different dyno.
Guys, need your help......
Link to results slip below, nowhere near what was expected need help if am reading wrong or need to try a different dyno.
http://rides.webshots.com/photo/2634...53427645HOIVYL
Dyno Dynamcs aka ( Heartbreaker ) Rolling Road
330lb ft Torque @ flywheel
260.5 hp @ flywheel
If i take 20% loss off that for drag, tansmission etc only just over 200RWHP........
The RR tech took her for a spin and said great drive really good low down torque and feels about rightfor a 300RWHP car..... but figures do not agree..!
Link to results slip below, nowhere near what was expected need help if am reading wrong or need to try a different dyno.
Guys, need your help......
Link to results slip below, nowhere near what was expected need help if am reading wrong or need to try a different dyno.
http://rides.webshots.com/photo/2634...53427645HOIVYL
Dyno Dynamcs aka ( Heartbreaker ) Rolling Road
330lb ft Torque @ flywheel
260.5 hp @ flywheel
If i take 20% loss off that for drag, tansmission etc only just over 200RWHP........
The RR tech took her for a spin and said great drive really good low down torque and feels about rightfor a 300RWHP car..... but figures do not agree..!
Last edited by V8 Str; 07-06-2012 at 10:28 AM.
#2
#3
Dynoed with TC off, 4th gear on j gate.... but he did say struggled to keep it in one gear...?... My thoughts is that the dyno is wrong, car seems to be fine and running well. There is another dyno about two hours or so away going to have a re-run there just to check i think, Before i look at the car itself. Thanks
#4
#5
Join Date: Oct 2009
Location: Perth Ontario Canada
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Dyno Dynamcs aka ( Heartbreaker ) Rolling Road
330lb ft Torque @ flywheel
260.5 hp @ flywheel
If i take 20% loss off that for drag, tansmission etc only just over 200RWHP........
The RR tech took her for a spin and said great drive really good low down torque and feels about rightfor a 300RWHP car..... but figures do not agree..!
#6
#7
I am confused Mikey, lol.... the figures on the print out i have say 330 & 260@flywheel are you saying i should add 20% to this to get correct figure...?
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#8
Join Date: Oct 2009
Location: Perth Ontario Canada
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In any case, no chassis dyno directly measures flywheel torque, only rear wheel. Possibly they call the rotating drum the wheels rest on 'a flywheel'?
#9
Indeed, although the dyno sheet reads "flywheel" , it is in fact wheel horsepower, and it's only labelled flywheel for whatever reason, i have noticed this on dyno dynamics and dynapack dyno's read outs as well.
Add the 20% to your values, there is NO WAY the read out applied a minus correction factor in an attempt to show you real "flywheel" horsepower.
Based on your current numbers posted of 330 wheel torque, seems like it's about right for the kind of dyno you were on.
I'm not sure why STR owners keep going to dyno shops thinking they're going to get anything other than disappointing results. Between the electronics and drivetrain loss, you're only in for heartbreak.
Trap speeds at the track (MPH) says it all!
Add the 20% to your values, there is NO WAY the read out applied a minus correction factor in an attempt to show you real "flywheel" horsepower.
Based on your current numbers posted of 330 wheel torque, seems like it's about right for the kind of dyno you were on.
I'm not sure why STR owners keep going to dyno shops thinking they're going to get anything other than disappointing results. Between the electronics and drivetrain loss, you're only in for heartbreak.
Trap speeds at the track (MPH) says it all!
#10
Indeed, although the dyno sheet reads "flywheel" , it is in fact wheel horsepower, and it's only labelled flywheel for whatever reason, i have noticed this on dyno dynamics and dynapack dyno's read outs as well.
Add the 20% to your values, there is NO WAY the read out applied a minus correction factor in an attempt to show you real "flywheel" horsepower.
Based on your current numbers posted of 330 wheel torque, seems like it's about right for the kind of dyno you were on.
I'm not sure why STR owners keep going to dyno shops thinking they're going to get anything other than disappointing results. Between the electronics and drivetrain loss, you're only in for heartbreak.
Trap speeds at the track (MPH) says it all!
Add the 20% to your values, there is NO WAY the read out applied a minus correction factor in an attempt to show you real "flywheel" horsepower.
Based on your current numbers posted of 330 wheel torque, seems like it's about right for the kind of dyno you were on.
I'm not sure why STR owners keep going to dyno shops thinking they're going to get anything other than disappointing results. Between the electronics and drivetrain loss, you're only in for heartbreak.
Trap speeds at the track (MPH) says it all!
My Proscan 0-60 time via my OBD and PC read 4.9secs on my last run, need to do a 1/4 mile timing and see what it throws up, nearest strip is Santa Pod 4hrs away...?.... but car seems to go well and pull well that is ultimately all that matters in reality..!
#11
#12
these cars are tough to dyno because they always want to downshift from 4th to third.
I've heard the dyno dynamics are about 12% low; which still puts you less than 300 rwhp. The 360-370 figure is pretty optomistic. Do any of your friends have the applications on their phone where they can calculate rough hp based off acceleration #'s and weight? Since there's not many dyno's and the track is too far, maybe that will work.
I've heard the dyno dynamics are about 12% low; which still puts you less than 300 rwhp. The 360-370 figure is pretty optomistic. Do any of your friends have the applications on their phone where they can calculate rough hp based off acceleration #'s and weight? Since there's not many dyno's and the track is too far, maybe that will work.
#13
These cars only want to down shift if the operator floors it before around 4200 rpm or so. The downshift will not happen later any more obviously, so there you have a clean measurement. There is nothing magical here…
Hard to judge this dual drum per wheel dyno, i prefer dynos that have only 1 drum per wheel. Runs in 4th gear could take longer due to the higher resistance of the 2 small drums per wheel, causing more heat buildup in the intercooler system for insatance and thus power loss.
Here is an example of a dyno dynamics run, with a relativly similar car/setup:
Many operators display a flywheel hp figure; this can be either based on a calculation (which dyno dynamics use) or on losses measured during coasting. Anyway, what you see on the print out is what the operator selects to print. If unsure, ask them what they printed, and ask a true rwhp printout.
Also you can’t make out anything from the dyno slip, so can’t make any further comments.
Hard to judge this dual drum per wheel dyno, i prefer dynos that have only 1 drum per wheel. Runs in 4th gear could take longer due to the higher resistance of the 2 small drums per wheel, causing more heat buildup in the intercooler system for insatance and thus power loss.
Here is an example of a dyno dynamics run, with a relativly similar car/setup:
Many operators display a flywheel hp figure; this can be either based on a calculation (which dyno dynamics use) or on losses measured during coasting. Anyway, what you see on the print out is what the operator selects to print. If unsure, ask them what they printed, and ask a true rwhp printout.
Also you can’t make out anything from the dyno slip, so can’t make any further comments.
#14
#15
From 4500 rpm your power isn't even growing anymore, so eventough if the numbers where low, it should have grown there. Maybe it was a bad run with heatsoaked intercooler.
Did you do just 1 run? Didn't they measure you a/f ratio (so important to always ask for !). Have you checked your boost pressure? All that info could help explain the results.
Bytheway, KenneBell doesn't recommend the gator back belts, so maybe even some belt slip could have played a role (boost check would have shown this).
What size belt do you use?
Did you do just 1 run? Didn't they measure you a/f ratio (so important to always ask for !). Have you checked your boost pressure? All that info could help explain the results.
Bytheway, KenneBell doesn't recommend the gator back belts, so maybe even some belt slip could have played a role (boost check would have shown this).
What size belt do you use?
#16
For me that site is unusable as when I click to look at the image larger it does something stupid. I'll try to upload just the image below.
I don't know what the Dyno Dynamics machine is actually doing to show what it calls "flywheel ..." but clearly it's not really displaying any such thing if they didn't unbolt the trans and attach the machine to the flywheel LOL (So, kinda pointless BS. Just adds confusion.)
Well.... what's with the car (or possibly the dyno)? From the few others I've seen, the TQ curve looks wrong for an STR. Also the peak HP looks to be at too low RPM.
Don't expect to be within 20% with any dyno app (PC, smartphone or whatever).
I don't know what the Dyno Dynamics machine is actually doing to show what it calls "flywheel ..." but clearly it's not really displaying any such thing if they didn't unbolt the trans and attach the machine to the flywheel LOL (So, kinda pointless BS. Just adds confusion.)
Well.... what's with the car (or possibly the dyno)? From the few others I've seen, the TQ curve looks wrong for an STR. Also the peak HP looks to be at too low RPM.
Don't expect to be within 20% with any dyno app (PC, smartphone or whatever).
Last edited by JagV8; 07-07-2012 at 03:48 AM.
#17
Thanks guys,
Clearly becoming apparent this dyno was worthless....lol
The run was one single run, hot engine, bonnet down with single fan... the slip says intake temp @23 degrees, tie that in with a uprated pulley spinning the charger faster and heatsoak sets in as Andre said. As above posters have said car does not reach peak RPM for Peak HP output. Lots of anomolies plus no idea what a flywheel figure is, if i take it as RWHP the heatsoak would explain slight down in torque and the major down on HP.
Avos belt fitted with uprated pulley by tuner he fits them with the upgrades and has never had issue with them on the Eaton, he did say though the higher spinning/heating on the heaton will help low down torque but could be a trade against outright BHP.
Water injection and better cooling/airflow may be the answer to get what i should be getting...?
I think a new run somewhere else, with adequate cooling and ask the right questions is in order
Clearly becoming apparent this dyno was worthless....lol
The run was one single run, hot engine, bonnet down with single fan... the slip says intake temp @23 degrees, tie that in with a uprated pulley spinning the charger faster and heatsoak sets in as Andre said. As above posters have said car does not reach peak RPM for Peak HP output. Lots of anomolies plus no idea what a flywheel figure is, if i take it as RWHP the heatsoak would explain slight down in torque and the major down on HP.
Avos belt fitted with uprated pulley by tuner he fits them with the upgrades and has never had issue with them on the Eaton, he did say though the higher spinning/heating on the heaton will help low down torque but could be a trade against outright BHP.
Water injection and better cooling/airflow may be the answer to get what i should be getting...?
I think a new run somewhere else, with adequate cooling and ask the right questions is in order
Last edited by V8 Str; 07-07-2012 at 07:58 AM.
#18
these cars are tough to dyno because they always want to downshift from 4th to third.
I've heard the dyno dynamics are about 12% low; which still puts you less than 300 rwhp. The 360-370 figure is pretty optomistic. Do any of your friends have the applications on their phone where they can calculate rough hp based off acceleration #'s and weight? Since there's not many dyno's and the track is too far, maybe that will work.
I've heard the dyno dynamics are about 12% low; which still puts you less than 300 rwhp. The 360-370 figure is pretty optomistic. Do any of your friends have the applications on their phone where they can calculate rough hp based off acceleration #'s and weight? Since there's not many dyno's and the track is too far, maybe that will work.
Last edited by bfsgross; 07-07-2012 at 08:00 AM.
#19
You can check yourself the belt partno, or ask your tuner which belt, as I wouldn't be surprised if one is choosen that hasn't an ideal lentgh.
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V8 Str (07-08-2012)
#20
There are not many that actually do dynos/check the true power, and before you did this you where proably happy with the pulley, so even if he would have installed a couple it doesn't mean there aren't any issues possible. He could prove this if he would have some dynos, so that would be a good question anyhow.
You can check yourself the belt partno, or ask your tuner which belt, as I wouldn't be surprised if one is choosen that hasn't an ideal lentgh.
You can check yourself the belt partno, or ask your tuner which belt, as I wouldn't be surprised if one is choosen that hasn't an ideal lentgh.