Rob_Mitchell Posted June 21, 2012 Share Posted June 21, 2012 Yeah bit lost with all this but interesting read. I couldnt really care what my car is producing.... i still know i cant handle it when i try give it some , and mines a baby! Quote Link to comment Share on other sites More sharing options...
Nodalmighty Posted June 21, 2012 Share Posted June 21, 2012 I think we've all forgotten the purpose of a dyno. It's a tuning tool and any numbers from it are specific to it and no other. Anyone who tuned a car on a dyno and then didn't check it again on the road is asking for trouble as a dyno (with the exception of a Mustang) and cell (with the exception of Mira) can not reproduce the loading and air flow characteristics of the real world. Bruntingthorpe is the best / safest place to map a car IMHO as you also get the chance to do all the drivablity tweeks on the way there. Lyndon. Quote Link to comment Share on other sites More sharing options...
Robzki Posted June 21, 2012 Share Posted June 21, 2012 I assume its just a willy waving exercise these days. Quote Link to comment Share on other sites More sharing options...
hodge Posted June 21, 2012 Share Posted June 21, 2012 I assume its just a willy waving exercise these days. BOOOOOOOOM. You nailed it dude. I said this in the LAST Dyno thread. It's all to do with nob waving. We're all guilty of it at 1 time on other, it's human nature. Quote Link to comment Share on other sites More sharing options...
JamieP Posted June 21, 2012 Author Share Posted June 21, 2012 I assume its just a willy waving exercise these days. If that was the case I would be keeping quiet, I'm saying my willy is not as big as once thought;) Quote Link to comment Share on other sites More sharing options...
Supra Kong Posted June 21, 2012 Share Posted June 21, 2012 fact is a dyno is the only way we can tell what difference the modifications we have done to our cars have made Some people can handle the truth, others cant Don't agree!! You should feel the difference! Otherwise whatever mod you have done was a waste of cash!! (-: It's about how it performs on the road or track! Anything else is for the pub! Quote Link to comment Share on other sites More sharing options...
Rob_Mitchell Posted June 21, 2012 Share Posted June 21, 2012 Don't agree!! You should feel the difference! Otherwise whatever mod you have done was a waste of cash!! (-: It's about how it performs on the road or track! Anything else is for the pub! Now look what you have done! im thirsty.... be right back just popping down the local in my 2000bhp twin engine'd supra Quote Link to comment Share on other sites More sharing options...
Supra Kong Posted June 21, 2012 Share Posted June 21, 2012 Now look what you have done! im thirsty.... be right back just popping down the local in my 2000bhp twin engine'd supra Wow, that sounds fast dude!!!! Quote Link to comment Share on other sites More sharing options...
chazuk Posted June 21, 2012 Share Posted June 21, 2012 Good thread no one should have really added anything on themselves that’s where it started going wrong. I do think its funny how many people sig's have changed recently though or those that only post up the calculated flywheel graph allot of people get carried away on figures and it does make me wonder if they actually keep/run the high boost setting after the rolling road Quote Link to comment Share on other sites More sharing options...
Matt H Posted June 21, 2012 Share Posted June 21, 2012 Interesting read this one Surely the real Dyno is on the strip In terms of measuring terminal speed's and quarter mile times ? Not really, that just shows your car is set up well for that type of thing. Quote Link to comment Share on other sites More sharing options...
Robzki Posted June 21, 2012 Share Posted June 21, 2012 BOOOOOOOOM. You nailed it dude. I said this in the LAST Dyno thread. It's all to do with nob waving. We're all guilty of it at 1 time on other, it's human nature. If that was the case I would be keeping quiet, I'm saying my willy is not as big as once thought;) I'm out too. Quote Link to comment Share on other sites More sharing options...
scoooby slayer Posted June 21, 2012 Share Posted June 21, 2012 Not really, that just shows your car is set up well for that type of thing. time is irrelevant but mph is a good indicator of hp. this graph has correlated well so far with my cars dyno print outs and running at santa pod. terminal is what ur looking at, time is all down to car set up. Quote Link to comment Share on other sites More sharing options...
Ibrar Jabbar Posted June 21, 2012 Share Posted June 21, 2012 (edited) I'm not too clued up on Dynos, however it's clear from both of my results that there is hardly any difference from fly and hub figures as Jamie mentions. Maybe somebody else could try it out just to set the record straight? Edited June 22, 2012 by Ibrar Jabbar spelling (see edit history) Quote Link to comment Share on other sites More sharing options...
dan294 Posted June 21, 2012 Share Posted June 21, 2012 I've emailed the guy that writes our dyno software from Germany. Not naming names, but he knows his stuff. Will post the results tomorrow of what he says. I personally think the twin roller systems like dyno dynamics aren't that accurate with high powe cars. The single roller systems are far more accurate. But that's my opinion. Things like wheelspin etc will make figures unrealistic, especially on the twin roller dynos. Quote Link to comment Share on other sites More sharing options...
DARETT Posted June 21, 2012 Share Posted June 21, 2012 I've emailed the guy that writes our dyno software from Germany. Not naming names, but he knows his stuff. Will post the results tomorrow of what he says. I personally think the twin roller systems like dyno dynamics aren't that accurate with high powe cars. The single roller systems are far more accurate. But that's my opinion. Things like wheelspin etc will make figures unrealistic, especially on the twin roller dynos. I agree, single roller systems work well without many strapping issues like on the DD. Its a shame there's not many around here. There is a land and sea Dynomite dyno that has just opened around the corner from me, apparently rated to 1500hp but I have no experience of them before. I think Bjork ran his car on one of them before and his results seemed about right for his 1/4 mile traps Quote Link to comment Share on other sites More sharing options...
dan294 Posted June 21, 2012 Share Posted June 21, 2012 Ours is rated to 1000hp and 3800nm. We've had a few high Hp cars that have reproduced similar figures to other single roller dynos. I'd be interested to see what someone in the know says regarding comparisons. Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted June 22, 2012 Share Posted June 22, 2012 Unfortunately, so long as car manufacturers quote flywheel figures for power outputs, people will come up with make believe flywheel figures. Quote Link to comment Share on other sites More sharing options...
dan294 Posted June 22, 2012 Share Posted June 22, 2012 My reply back from our Dyno software writer, who is extremely highly regarded in the world of Dyno software etc. So rather than speculation, a more accurate answer from someone that knows exactly what they are talking about: Hi Dan, Good to hear from you. *Aside from the obvious, what are the main differences between a Hub Dyno and one like ours? +++ best to mention the obvious: - price (hub dynos are usually more) - hub dynos cannot run for extended periods (heat), some better than others - hub dyno takes a long time to get ready for a power run *I know ours calculates a Flywheel figure +++ in simple form: yours measures the power arriving at the rollers (which is flywheel power less different losses), during the coast down we "try" to sumarize these losses and add them to the power at the rollers (we call this power@wheels, but really it is power@rollers) and we get a very good estimate of the power at the flywheel like this. We do. Others don't get it right so well. Hub dyno: you get power at flywheel less losses in drivetrain (gearbox and differential). example gearbox losses: typical gearbox losses on a BMW 6 speed box are 4th gear 3%, 5th gear 1%, 6th gear 3%. diff losses. no idea...would also be non-negligible, you have crown wheel and pinion, that'll chew up some power, no doubt...2%...5% ? no idea. *Is a Hub Dyno the same, or is that more like a flywheel figure already? +++ as stated above...probably flywheel less 3....7% , depends on car and corresponding losses. Question: so how does one know how to add to compensate ? Very hard work ! Get the data from a mate who's mate is the R&D engineer at Getrag gearbox factory and at ZF gearbox factory and then get it for all models and cars... hardly likely. It's alos a guestimate, I would say. Also, the gearbox oil temp and diff oil temp will make a difference, too. *Do you still get the same transmission percentage losses on a hub Dyno? +++ in the transmission drive line I would say : yes. But the rolling road has high tyre losses, to (the deformation of the soft rubber on the roller). Are you writing up a thesis on this or is there a more specific reason for your question ? I would say: the only really accurate way to test an engine is to have it on an engine dynamometer and this needs to be calibrated spot on before. Kind Regards, Rudi Quote Link to comment Share on other sites More sharing options...
Jamesy Posted June 22, 2012 Share Posted June 22, 2012 (edited) I see people have been quoting the same kind of figures for years and years - usually either fwhp or rwhp, not sure why all of a sudden there's a big shift in views either side or why years of old figures would now be wrong. But as mentioned on the last thread some people, including me, have got way too caught up chasing numbers in the past... my current 600+hp is crazy on the road and i'd personally never go after bigger bhp chasing again In my experiences @ SRR you always get a fwhp reading from the dyno - and i was told an auto has around 5% more losses than a manual by the dyno operator (15% losses for manual, 20% losses for auto). Then at TDi you get a hub reading and Sam said if you want to work out your fwhp its around 20% losses for auto, 15% for manuals... yes these are a guess and maybe a few % over or under. These are the only 2 places i have used and have been told by the guys who run/own the dynos Edited June 22, 2012 by Jamesy (see edit history) Quote Link to comment Share on other sites More sharing options...
Luxluc Posted June 22, 2012 Share Posted June 22, 2012 Nice write up Dan Quote Link to comment Share on other sites More sharing options...
Rob_Mitchell Posted June 22, 2012 Share Posted June 22, 2012 I'm out too. yeah me three! im hung like a hamster plus i have a small turbo... the only thing i got going for me is that i aint ginger Quote Link to comment Share on other sites More sharing options...
dan294 Posted June 22, 2012 Share Posted June 22, 2012 Nice write up Dan I just copied and pasted the email back from him! Quote Link to comment Share on other sites More sharing options...
Jellybean Posted June 22, 2012 Share Posted June 22, 2012 Just on a side note , I think Torque gets left out alot of the time which is just as relevant if not more important Is it a rule of thumb , the BHP and Torque should be relatively similar for an impressive setup? Quote Link to comment Share on other sites More sharing options...
scoooby slayer Posted June 23, 2012 Share Posted June 23, 2012 well ive just spent a while studying rototest real world test results http://www.rri.se/index.php?DN=29 after reading through there if you want to correlate a tdi hub graph to flywheel power then divide the result by 0.93. thats 7% losses. ive come to that figure from looking at high power rwd cars from there tests. dynapack i cant say as its a different dyno. Quote Link to comment Share on other sites More sharing options...
wallis Posted June 23, 2012 Share Posted June 23, 2012 Just on a side note , I think Torque gets left out alot of the time which is just as relevant if not more important Is it a rule of thumb , the BHP and Torque should be relatively similar for an impressive setup? Torque is as important as bhp if not more and the delivery of it to have a fast car. A question I keep asking myself is if two cars have the same amount of torque but different bhp , would there be any difference in performance? I see allot of bigger bhp cars losing more and more torque the more bhp bhp they get? Most of the best cars have similar bhp to torque if u look at the figures. Quote Link to comment Share on other sites More sharing options...
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