Scott Posted March 22, 2010 Share Posted March 22, 2010 Having an interesting discussion regarding transmission losses in another thread. Just looking to collect some input from the guys who have had a run at the same dyno. I know that SRR is the most popular so I have written that in the heading but any input would be appreciated, just please write the RR next to your HP. Looking for RWHP figures and FWHP figures if you have them, RWHP being the most important for now. Could you also put whether you are Auto Or manual. Scott - SRR - 350rwhp - 420fwhp - Manual Something like that. Thanks folks Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted March 22, 2010 Share Posted March 22, 2010 You drove all the way to SRR for a power run?! ...sorry, hijack over Quote Link to comment Share on other sites More sharing options...
Scott Posted March 22, 2010 Author Share Posted March 22, 2010 Just thinking about it, the reason I have asked for BPU and Stock is that the power will be fairly similar for a comparison in losses. Would appreciate guys with singles too as if I can get a manual RWHP and auto RWHP that are close, I can do the same calculation. The chances of getting them similar might be slim though. Quote Link to comment Share on other sites More sharing options...
Scott Posted March 22, 2010 Author Share Posted March 22, 2010 You drove all the way to SRR for a power run?! ...sorry, hijack over Mate, I drove all the way down to Japfest to meet some members and noone spoke to anyone. I'm THAT outgoing Quote Link to comment Share on other sites More sharing options...
Abz Posted March 22, 2010 Share Posted March 22, 2010 Scott, Gaz done this brilliant article of the SRR day we had a few months ago http://www.mkivsupra.net/vbb/showthread.php?t=204366&highlight=Surrey+Rolling+Road+Day Sorry I don't have the details on me but mine ran 352BHP (0.8 Bar), the only modification which had been done on my car was both cats had been removed and Paul put in a RR along with the decats, it also had a full service carried out. Mine is a Auto TT with 100k on the clock. Quote Link to comment Share on other sites More sharing options...
Scott Posted March 22, 2010 Author Share Posted March 22, 2010 (edited) Cheers mate, the figures quoted are all FWHP though, really need RWHP figures AND FWHP figures to do the comparison. Alex M's seems to be the closest comparison for what we are after. Edit: Picked out 2 that might be useful Supra Plant – Supra TT auto – 334.2bhp (stock) Alex M – Supra 5-speed N/A – 215.1bhp I think the auto transmission losses are estimated to be 20%. If that is the case, and you think it should be 30%, that would make the car actually producing 371.3hp. Same with the 5spd. I think it is taken as 15%, increase that to 25% and you get 239hp. The latter wouldn't be THAT unbelievable but 371hp from a bone stock TT is just too much. Edited March 22, 2010 by Scott (see edit history) Quote Link to comment Share on other sites More sharing options...
Homer Posted March 22, 2010 Share Posted March 22, 2010 Are you after drag coefficients & losses? That won't an exact science as all driveline components play a part in that ratio (diff drive ratio, gearbox, wheel weight, tyre weight, flywheel, etc). For what it's worth, my old car with a 6spd (same dyno, same shoot, similar atmospherics) BPU - 359rwhp, 429fwhp (19.5% loss) Single - 460rwhp, 545fwhp (18.5% loss) Quote Link to comment Share on other sites More sharing options...
Scott Posted March 22, 2010 Author Share Posted March 22, 2010 Are you after drag coefficients & losses? That won't an exact science as all driveline components play a part in that ratio (diff drive ratio, gearbox, wheel weight, tyre weight, flywheel, etc). For what it's worth, my old car (same dyno, same shoot, similar atmospherics) BPU - 359rwhp, 429fwhp (19.5% loss) Single - 460rwhp, 545fwhp (18.5% loss) No bud, it is to do with transmission losses as per Gman's thread. Is it not very strange that the %age of loss changed? Surely it should have been the same with the same drivetrain? Would that have been down to something like the flywheel/clutch? Quote Link to comment Share on other sites More sharing options...
Homer Posted March 23, 2010 Share Posted March 23, 2010 No bud, it is to do with transmission losses as per Gman's thread. Is it not very strange that the %age of loss changed? Surely it should have been the same with the same drivetrain? Would that have been down to something like the flywheel/clutch? Difficult one to answer as there are so many variables. Dynos measure drag rate in various ways, and in that the results vary considerably dependant on the dyno, it's operator and it's shootout configuration. For the results I posted: It's not an exact science (e.g. different rear tyre's were fitted between runs - BPU was on new tyres, single on old worn out ones, it's only going to be a couple of ib's or so or rubber, but with such a huge rotational mass that will make a big difference to final drive torque). 1-2% difference would be within acceptable variation on the same dyno, etc. Quote Link to comment Share on other sites More sharing options...
Scott Posted March 23, 2010 Author Share Posted March 23, 2010 Ahh that explains it Quote Link to comment Share on other sites More sharing options...
Mcgoo Posted March 23, 2010 Share Posted March 23, 2010 (edited) McGoo, TT6 @ 0.8bar - RWHP = 273.5 FWHP = 329.8 (20.58 % losses) Edited March 23, 2010 by Mcgoo Added printout (see edit history) Quote Link to comment Share on other sites More sharing options...
AndrewOW Posted March 23, 2010 Share Posted March 23, 2010 AndrewOW, Rebas Systems (Dyno Dynamics) - Auto @ 1bar, 314.6rwhp - 376.4fwhp - 16.41% loss. Is that right?! Quote Link to comment Share on other sites More sharing options...
AlexM Posted March 23, 2010 Share Posted March 23, 2010 (edited) SRR Dec 09 results.. Stock SZ 5spd - 215.1 FWHP, 173.8 RWHP (20.2% loss) BPU RZ Auto @ 0.8bar - 354 FWHP, 294.2 RWHP (16.9% loss) I'll see if I can find my SZ Auto results from May later.. Edited March 24, 2010 by AlexM (see edit history) Quote Link to comment Share on other sites More sharing options...
Scott Posted March 23, 2010 Author Share Posted March 23, 2010 Hmm the %age losses do seem a little odd. The Auto had less losses than the 5speed? It would seem that the Auto has 16-19% losses and the manual has approx 21% losses. Quote Link to comment Share on other sites More sharing options...
Bobbeh Posted March 23, 2010 Share Posted March 23, 2010 Manual should have less loss (18%) than an auto (over 20%). Quote Link to comment Share on other sites More sharing options...
AndrewOW Posted March 23, 2010 Share Posted March 23, 2010 So really, you'd be better off taking your car to several rolling roads, getting an average and going from there? Quote Link to comment Share on other sites More sharing options...
Scott Posted March 23, 2010 Author Share Posted March 23, 2010 Manual should have less loss (18%) than an auto (over 20%). Thats what I thought. I read manual as 16%ish and auto as 22%ish. Strange that. Quote Link to comment Share on other sites More sharing options...
Scott Posted March 23, 2010 Author Share Posted March 23, 2010 So really, you'd be better off taking your car to several rolling roads, getting an average and going from there? To be honest I think you could go to dyno's till the cows came home and struggle to find 2 the same. I think you could average out the RWHP figures to get a reasonably accurate power of the car, it seems the FWHP figures really are just pie in the sky. Quote Link to comment Share on other sites More sharing options...
Bobbeh Posted March 23, 2010 Share Posted March 23, 2010 Or at least to the ones that have been used by many members, SRR, G-Force, and Thor's dyna pak come to mind. My figures from a few years ago (stock boost with cats in) RR Figure - 265 RWHP - 323 FWHP (1% loss variation). 18 % loss figure. Hub figure - 306 RWHP - Fly and loss, no idea. Quote Link to comment Share on other sites More sharing options...
Multics Posted March 23, 2010 Share Posted March 23, 2010 Can of worms but since every dyno operator (of the same Dyno brand) inputs different loss compensation parameters, why do we insist on focusing on flywheel HP? Why don't we just stick to RWHP and live with it? Quote Link to comment Share on other sites More sharing options...
Stonkin Posted March 23, 2010 Share Posted March 23, 2010 because fwhp creates a higher number to share with friends rwhp would defintely be a more accurate figure for most dynos Quote Link to comment Share on other sites More sharing options...
Bobbeh Posted March 23, 2010 Share Posted March 23, 2010 ^Depends on the dyno Quote Link to comment Share on other sites More sharing options...
Graham S Posted March 23, 2010 Share Posted March 23, 2010 I had mine done at SRR a few years back, at the time it was running full decat and air filter, does it say on the graph for SRR what fly HP is as never noticed. but, SRR UK 6sp FWHP 404bhp Quote Link to comment Share on other sites More sharing options...
JamieP Posted March 23, 2010 Share Posted March 23, 2010 To be honest I think you could go to dyno's till the cows came home and struggle to find 2 the same. Even the same dyno will give different readings on different days, ive seen a change of 30bhp on srr the day after with no change to anything except a cooler engine. Quote Link to comment Share on other sites More sharing options...
miko_supra Posted March 23, 2010 Share Posted March 23, 2010 because fwhp creates a higher number to share with friends rwhp would defintely be a more accurate figure for most dynos Manufacturers also always quote fly wheel hp. So I guess it makes it easier for comparisons as most people aren't familiar wheel hp figures. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.