Richard71 Posted July 5, 2019 Report Share Posted July 5, 2019 55 minutes ago, Cameron said: Trust you do pick about the furthest away place you could , any excuse for a long drive. Cameron There's madness in my method (or something like that), I have an old pal in the neck of the woods, not seen each other in years, an excuse for a catch up. Richard. Quote Link to post Share on other sites
CK's TR6 Posted July 5, 2019 Report Share Posted July 5, 2019 Curious, you wouldn’t have the torque curve vs RPM would you? I’ll assume rolling road and these curves (including) torque are the corrected to flywheel amounts, yes? Trying to compare apples to apples as it were. In the states, we use hp & torque vs RPM for the graphs. Sometimes just at the wheel if it’s a rolling road, sometimes corrected to flywheel if rolling road. Quote Link to post Share on other sites
Graham Posted July 5, 2019 Author Report Share Posted July 5, 2019 2 hours ago, CK's TR6 said: Curious, you wouldn’t have the torque curve vs RPM would you? I’ll assume rolling road and these curves (including) torque are the corrected to flywheel amounts, yes? Trying to compare apples to apples as it were. In the states, we use hp & torque vs RPM for the graphs. Sometimes just at the wheel if it’s a rolling road, sometimes corrected to flywheel if rolling road. As soon as I get the hard copy print outs I will scan and post them Quote Link to post Share on other sites
CK's TR6 Posted July 6, 2019 Report Share Posted July 6, 2019 Graham, I did a little linear regression analysis on RPM vs road speed estimates correlated with the corrected HP, flywheel hp, and torques values from the plots. It is all pretty consistent. For those who care, HP = (torque x RPM)/5252 I would say this is true at the flywheel. Correcting for drive train losses is ripe for argument. It seems your dyno folks used a total of about 27% loss, some of that was environmental (hotter than standard day, pressure altitude etc) I'm sure. Modern drive trains are a bit lower but then again, some of us have Toyota transmissions and nissan diffs and CV halfshafts. Your engine shows a good flat torque curve with best torque around 5035 RPM (estimate). That would be your VEmax point assuming that AFR's were good and ignition was optimized. I would say that you could get a little more torque at this top end if you had a crank fired and mapped (16x16 table) non dizzy system. Which means you would see HP gains as the RPM increased right up to your and your wallet's limit. A Racetorations billet crank, block brace, cast sump, carrillo's, and light weight pistons, what? good to 7K maybe. If the torque stayed up around 180 lbft, that would be 240hp. It's just money, right? Quote Link to post Share on other sites
Steves_TR6 Posted July 6, 2019 Report Share Posted July 6, 2019 I think ‘transmission losses’ are measured byt the rolling road arent they? the rr measures the effort required to turn the drivetrain at the end of the power run, ie on the way back down the rev range. having said that Enginuity took 10 hp off the reading for my car, which i never understood? steve Quote Link to post Share on other sites
Graham Posted July 6, 2019 Author Report Share Posted July 6, 2019 6 hours ago, CK's TR6 said: Graham, I did a little linear regression analysis on RPM vs road speed estimates correlated with the corrected HP, flywheel hp, and torques values from the plots. It is all pretty consistent. For those who care, HP = (torque x RPM)/5252 I would say this is true at the flywheel. Correcting for drive train losses is ripe for argument. It seems your dyno folks used a total of about 27% loss, some of that was environmental (hotter than standard day, pressure altitude etc) I'm sure. Modern drive trains are a bit lower but then again, some of us have Toyota transmissions and nissan diffs and CV halfshafts. Your engine shows a good flat torque curve with best torque around 5035 RPM (estimate). That would be your VEmax point assuming that AFR's were good and ignition was optimized. I would say that you could get a little more torque at this top end if you had a crank fired and mapped (16x16 table) non dizzy system. Which means you would see HP gains as the RPM increased right up to your and your wallet's limit. A Racetorations billet crank, block brace, cast sump, carrillo's, and light weight pistons, what? good to 7K maybe. If the torque stayed up around 180 lbft, that would be 240hp. It's just money, right? Yep I think you can safely say I've reached the limit of what I can afford................ but possibly not what is achievable. Quote Link to post Share on other sites
Motorsport Mickey Posted July 6, 2019 Report Share Posted July 6, 2019 2 hours ago, Steves_TR6 said: I think ‘transmission losses’ are measured byt the rolling road arent they? the rr measures the effort required to turn the drivetrain at the end of the power run, ie on the way back down the rev range. having said that Enginuity took 10 hp off the reading for my car, which i never understood? steve Over inflated tyres allowance ? Mick Richards Quote Link to post Share on other sites
Steves_TR6 Posted July 6, 2019 Report Share Posted July 6, 2019 1 hour ago, Motorsport Mickey said: Over inflated tyres allowance ? Mick Richards I dont understand how tyre pressure would affect the readings Mick? Quote Link to post Share on other sites
RogerH Posted July 6, 2019 Report Share Posted July 6, 2019 Hi Steve, could it be to do with tyre diameter!! Roger Quote Link to post Share on other sites
Waldi Posted July 6, 2019 Report Share Posted July 6, 2019 A soft tire absorbs more energy, so the transmission losses increase and vice versa. So hard tires will result in higher measured power. Regards, Waldi Quote Link to post Share on other sites
Steves_TR6 Posted July 6, 2019 Report Share Posted July 6, 2019 Thanks, that makes some sense, but my tyres were at their normal pressure. Quote Link to post Share on other sites
Motorsport Mickey Posted July 6, 2019 Report Share Posted July 6, 2019 (edited) I was picking up on the posting about the other TR6 having it’s tyres blown up so it didn’t sit on the rolling road frame. As Waldi says it’s not unusual for an unscrupulous rolling road to blow tyres up to 40 lbs for better hp figures, so always scrutinise the dyno printout to check. So allowing a 10 hp downgrade when done would be generous, I’d expect less than 5 benefit. Mick Richards Edited July 6, 2019 by Motorsport Mickey Quote Link to post Share on other sites
Peter Cobbold Posted July 6, 2019 Report Share Posted July 6, 2019 Opening the boonet to allow cold air to intakes. 20C vs 60C adds about 3% Quote Link to post Share on other sites
Richard71 Posted July 17, 2019 Report Share Posted July 17, 2019 Earlier this week Revington TR rolling road tuned my car. They tell me their rolling road is only for tune up purposes etc, so I have no print out or hardfast figures. However they tell me the car pulled 114hp at the rear wheels (at what RPM I don't know) and with their educated experienced guestimate upwards of 170hp at the flywheel. I have plenty of engine dyno testing through work, but know nothing of rolling road testing, so don't know if those guestimated figures are probable, what I do know is the car pulls like a train and is a pleasure to drive. Richard. Quote Link to post Share on other sites
DRD Posted July 17, 2019 Report Share Posted July 17, 2019 20 minutes ago, Richard71 said: Earlier this week Revington TR rolling road tuned my car. They tell me their rolling road is only for tune up purposes etc, so I have no print out or hardfast figures. However they tell me the car pulled 114hp at the rear wheels (at what RPM I don't know) and with their educated experienced guestimate upwards of 170hp at the flywheel. I have plenty of engine dyno testing through work, but know nothing of rolling road testing, so don't know if those guestimated figures are probable, what I do know is the car pulls like a train and is a pleasure to drive. Richard. Transmission losses are usually around 30hp - putting it in the 145hp ballpark which sounds reasonable for a 6. Quote Link to post Share on other sites
Richard71 Posted July 17, 2019 Report Share Posted July 17, 2019 7 minutes ago, DRD said: Transmission losses are usually around 30hp - putting it in the 145hp ballpark which sounds reasonable for a 6. Maybe I mis-heard him and he actually said 140hp at the wheels, or maybe I'm dreaming with ambition? The engine has had some performance upgrades, either way I'm content with how it runs, 1200 miles since Saturday and it never missed a beat! Richard. Quote Link to post Share on other sites
Steves_TR6 Posted July 17, 2019 Report Share Posted July 17, 2019 30hp loss in transmission is consistent with my car’s 143 at the wheels which showed 172 on the screen at Enginuity Quote Link to post Share on other sites
ntc Posted July 17, 2019 Report Share Posted July 17, 2019 3 hours ago, Richard71 said: Maybe I mis-heard him and he actually said 140hp at the wheels, or maybe I'm dreaming with ambition? The engine has had some performance upgrades, either way I'm content with how it runs, 1200 miles since Saturday and it never missed a beat! Richard. You will have, 140 at the wheels is good strong power and = about 170 flywheel if not a cad more. Quote Link to post Share on other sites
CK's TR6 Posted July 18, 2019 Report Share Posted July 18, 2019 This guy might be right or might be wrong: http://www.superstreetonline.com/how-to/engine/modp-1005-drivetrain-power-loss Quote Link to post Share on other sites
Hamish Posted July 18, 2019 Report Share Posted July 18, 2019 In the club sprint and Hillclimb champs we have power weight classes and use this calculation eg my class is 2a <130bhp/tonne “Where the power is at the Flywheel, which can be calculated from the power at the wheels plus 15% plus 10HP, and the weight is the weight of the car in its normal competition state excluding the driver. “ Quote Link to post Share on other sites
DRD Posted July 18, 2019 Report Share Posted July 18, 2019 5 hours ago, CK's TR6 said: This guy might be right or might be wrong: http://www.superstreetonline.com/how-to/engine/modp-1005-drivetrain-power-loss Yep a good article - the only figure that you can rely on is the wheel hp and then it depends on the rolling road and you can't assume that they will all agree. You can only really compare cars on the same rolling road on the same day. Quote Link to post Share on other sites
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