Topic for an argument
Discussion
Will
Everyone is entitled to their own preferences and opinions, as you have ably demonstrated both with this post and on many others before now. It is therefor inevitable in situations where preferences differ that someone may offer up an opinion that is at odds with yours. That I am afraid is life.
However I am intrigued as to why your preference is towards Dyna Pack. What benefits does this method offer over a rolling road ?
Best Regards
Allan
Opininated Salesman of WRC
Everyone is entitled to their own preferences and opinions, as you have ably demonstrated both with this post and on many others before now. It is therefor inevitable in situations where preferences differ that someone may offer up an opinion that is at odds with yours. That I am afraid is life.
However I am intrigued as to why your preference is towards Dyna Pack. What benefits does this method offer over a rolling road ?
Best Regards
Allan
Opininated Salesman of WRC
I have a similar view to the use of measuring systems, but have no general preference of either technique, i.e. RR or HUB systems.
I think the biggest issue people have with output measuring devices is the variability.
That is not always an issue with the device, but normally with the lack of understanding of what the measurement units are and also the fascination with trying to determine the output at the flywheel.
My general view is that as long as everyone compares on the day @ the wheels and the measuring device is well set-up and used competently, the comparison between one car and another is perfectly valid.
The flywheel extrapolation methods sometimes do leave a little to be desired so I tend to ignore them to a certain extent (except fo bullsh1t in the pub).
When measuring on two different systems (they should all be calibrated, but hey!?!), it is best to use the returns as a guide only.
That's why people invented the Dyno Day, all compared on the day, no bull!
P.S. just as a note:
My preference is DIN HP at the wheels and as the car is set-up for the road. (I use DIN as that is pretty much what you see in the mags consistenly and its easy to convert all power measurements to it).
IMHO: you should drive the car in, ensure it won't blow up with simple checks and dyno it @ the wheels.
Use the numbers to determine improvements. if you start modifying without dynoing first then you'll never know.
Anything else is just numbers for numbers sake. But I like to drive the car, I don't spec it.
P.P.S: Will, get on with your work! and send me the cable, I've dyno'ed it now, time to damage it!
I think the biggest issue people have with output measuring devices is the variability.
That is not always an issue with the device, but normally with the lack of understanding of what the measurement units are and also the fascination with trying to determine the output at the flywheel.
My general view is that as long as everyone compares on the day @ the wheels and the measuring device is well set-up and used competently, the comparison between one car and another is perfectly valid.
The flywheel extrapolation methods sometimes do leave a little to be desired so I tend to ignore them to a certain extent (except fo bullsh1t in the pub).
When measuring on two different systems (they should all be calibrated, but hey!?!), it is best to use the returns as a guide only.
That's why people invented the Dyno Day, all compared on the day, no bull!
P.S. just as a note:
My preference is DIN HP at the wheels and as the car is set-up for the road. (I use DIN as that is pretty much what you see in the mags consistenly and its easy to convert all power measurements to it).
IMHO: you should drive the car in, ensure it won't blow up with simple checks and dyno it @ the wheels.
Use the numbers to determine improvements. if you start modifying without dynoing first then you'll never know.
Anything else is just numbers for numbers sake. But I like to drive the car, I don't spec it.
P.P.S: Will, get on with your work! and send me the cable, I've dyno'ed it now, time to damage it!
Good post there Eric
My view (opinionated and without any substantive back up) is that rear wheel figures are very accurate on the hub system, this cannot be so on a rolling road due to tyre pressures/heat/ tyre friction, contact tread area etc. and it is less stressful for the car. Also getting the figures at the engine will always be open to debate with any system so some of us use rwbhp as the definative benchmark.
Thats probally why some of the Wortec fettled cars did not run on the rollin road
My view (opinionated and without any substantive back up) is that rear wheel figures are very accurate on the hub system, this cannot be so on a rolling road due to tyre pressures/heat/ tyre friction, contact tread area etc. and it is less stressful for the car. Also getting the figures at the engine will always be open to debate with any system so some of us use rwbhp as the definative benchmark.
Thats probally why some of the Wortec fettled cars did not run on the rollin road
Cheers Will (for sending cable etc. I'll fix you up with a few beers next time for the postage etc.)
I agree on the RWKW/RWHP bit (as per my previous post) that is the best comparison regardless of the system you use.
RR's do tend to be more stressful, but not on the car, only the tyres. At the end of the day we have probably all mashed the welly in in fourth gear. A well set-up RR (operated properly! (as per Saturday's event)) should not be anymore stressful than being on the actual road.
I agree that the hub system does take away some of the inconsistencies of operator error, and that is a safe way to go if you have doubts on the operators competence, but a good RR operator will ensure load and tyre temps are good for the run, and watch for temps exceeding recomnmended sidewall maximums.
My preference for RRs is just because I feel that the tyre is where the road gets it, so the tyre should be where the measuring instrument gets it. (Also I like to see the dynamics of the car on a RR.
But to re-iterate, the only true way to make comparison is, regardless of system, do it on the same day on the same instrument.
Next time there's a HUB day I will come along for a go as a comparison. (Any Planned?)
P.S. if anyone feels that the RR is stressful to a car, don't give ME a go in your's, you will be disappointed.
>> Edited by v2hsv on Monday 15th August 13:48
I agree on the RWKW/RWHP bit (as per my previous post) that is the best comparison regardless of the system you use.
RR's do tend to be more stressful, but not on the car, only the tyres. At the end of the day we have probably all mashed the welly in in fourth gear. A well set-up RR (operated properly! (as per Saturday's event)) should not be anymore stressful than being on the actual road.
I agree that the hub system does take away some of the inconsistencies of operator error, and that is a safe way to go if you have doubts on the operators competence, but a good RR operator will ensure load and tyre temps are good for the run, and watch for temps exceeding recomnmended sidewall maximums.
My preference for RRs is just because I feel that the tyre is where the road gets it, so the tyre should be where the measuring instrument gets it. (Also I like to see the dynamics of the car on a RR.
But to re-iterate, the only true way to make comparison is, regardless of system, do it on the same day on the same instrument.
Next time there's a HUB day I will come along for a go as a comparison. (Any Planned?)
P.S. if anyone feels that the RR is stressful to a car, don't give ME a go in your's, you will be disappointed.
>> Edited by v2hsv on Monday 15th August 13:48
Just for those that know very little amongst you, surely even when cars are tested on the same machine on the same day, there are many variables. Tyre type, tyre pressure, how hot engine had got prior to the run, operator inconsistancy, if it started raining half way through etc etc ?
Just for my own knowledge, how does did the DD RR calculate the tansmission losses ?
Just for my own knowledge, how does did the DD RR calculate the tansmission losses ?
I didn't know there was a difference - but hey I only drive it. One thing puzzles me though. When I measured the pressure in my rear tyres after the dyno they were only at 30psi. I thought they were all being set at 40psi. Will it make that much difference to the results as the dyno chart shows 40psi as the tyre pressure?
BTW I have now set them to 36psi.
Would defo like to have another go on a dyno though!!
BTW I have now set them to 36psi.
Would defo like to have another go on a dyno though!!
One way to settle this story, not to prove which system is better than the other, but to do another shoot out day all together on the same day at a hub system place.
If you guys would like to get together again fo another social (which can't be a bad thing) and dyno testing I will arange.
Names please if interested.
If you guys would like to get together again fo another social (which can't be a bad thing) and dyno testing I will arange.
Names please if interested.
Jagsy,appreciate your comments but I have used hubs dyno pack, and have been told that 2 companies that operate this system differ in their calculations,used Maha rolling road,Dyno dynamics rolling road,etc.
and still find I am satisfied what i achieve.
You will never satisfy all so why do we not close gracefully on a very good weekend enjoyed by all!.
ps,found when I returned home on Sat that my ?? had no been working,could I have made more power if it had been working!!it will never be satisfactory for all.We are all entitled to beg to differ.Your comments will be received generously by all I am sure, but lets keep this in the spirit is intended,not a war.
and still find I am satisfied what i achieve.
You will never satisfy all so why do we not close gracefully on a very good weekend enjoyed by all!.
ps,found when I returned home on Sat that my ?? had no been working,could I have made more power if it had been working!!it will never be satisfactory for all.We are all entitled to beg to differ.Your comments will be received generously by all I am sure, but lets keep this in the spirit is intended,not a war.
What a strange post. As others have said, there will always be differences between the different power measuring systems - hub or rolling road - what really matters are power gains that are achieved, after mods are carried out, and the measurements carried out on the same system. Having said that, my car showed 350 at the hubs at abbey (dynapack) 359 at WRC before their remap - very close to the abbey fig but I'd put another 10k miles on since abbey so that could account for the extra few bhp - and 382 bhp after the remap, so it would seem that there is not that much difference between the systems. One thing I do know is that the throttle response is much better since the remap, so I'm happy.
pomona - you have a great car - enjoyed that run up the a34. It was good talking to you and I appreciate the logical way you have gone about modding your car and the results you have achieved. Far better than the "bodge on top of another bodge" process at huge expense that certain other companies seem to adopt.
Jag, count me in too.
Same, day same instrument is the most level playing field....more level than different day, different instrument.....anyone agree????
There are also many variables when driving on the road.......tyre type/pressure raining air pressure, temperature, suspension set-up......
but any instrument and measuring system has measuring tolerances: perhaps there needs to be a time slot that will please everybody (i.e. 4.00am in the mornign -40C air density at 1130mb etc. ????????????????
if I get within 10hp of the real figure or variance between dynos I don't care: 400hp produced, 10 hp error? 4% tolerance ----- GOOD INSTRUMENT: considering all the variables?
Thats life!
Same, day same instrument is the most level playing field....more level than different day, different instrument.....anyone agree????
There are also many variables when driving on the road.......tyre type/pressure raining air pressure, temperature, suspension set-up......
but any instrument and measuring system has measuring tolerances: perhaps there needs to be a time slot that will please everybody (i.e. 4.00am in the mornign -40C air density at 1130mb etc. ????????????????
if I get within 10hp of the real figure or variance between dynos I don't care: 400hp produced, 10 hp error? 4% tolerance ----- GOOD INSTRUMENT: considering all the variables?
Thats life!
Thank you Eric.
The reason I posted the suggestion was I thought poeple are interested in dyno testing. Note the number of discussions previous to this weekend and the number of folk that turned up this weekend.
So it is a good social and we should promote this to get people together and promote the cars.
So as we, in paritcular I, are learning about this experience, I would like to do this again.
As I have said already I couldn't give a monkeys fluff about the systems, we all know they will be different, we all know calibrations will be different. I just find it all interesting and lots to talk about.
Anyway, just a suggestion, 3 interested to join this miserable lonely northern bast'd
>> Edited by jagsy on Monday 15th August 20:24
The reason I posted the suggestion was I thought poeple are interested in dyno testing. Note the number of discussions previous to this weekend and the number of folk that turned up this weekend.
So it is a good social and we should promote this to get people together and promote the cars.
So as we, in paritcular I, are learning about this experience, I would like to do this again.
As I have said already I couldn't give a monkeys fluff about the systems, we all know they will be different, we all know calibrations will be different. I just find it all interesting and lots to talk about.
Anyway, just a suggestion, 3 interested to join this miserable lonely northern bast'd
>> Edited by jagsy on Monday 15th August 20:24
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