Dnk Posted June 12, 2018 Share Posted June 12, 2018 I've searched but can't find it Whats a ball park correction figure to the crank for an auto TT on a hub dyno ? 15 %, 20% or more ? Quote Link to comment Share on other sites More sharing options...
Frank Bullitt Posted June 12, 2018 Share Posted June 12, 2018 I found this a while ago whilst searching for the same, I don’t think the figure it gives is 100% as it’s a guestimator but it’s pretty close. https://www.mk5cortinaestate.co.uk/calculator4.php Quote Link to comment Share on other sites More sharing options...
Dnk Posted June 12, 2018 Author Share Posted June 12, 2018 Cheers Frank Works out at nearly 24 % loss on that Quote Link to comment Share on other sites More sharing options...
Burna Posted June 12, 2018 Share Posted June 12, 2018 I've always gone on 18 to 22% Quote Link to comment Share on other sites More sharing options...
Frank Bullitt Posted June 12, 2018 Share Posted June 12, 2018 Cheers Frank that'll do No problem, on their calculator an auto it works out about 24% and a manual at 17% I think. Quote Link to comment Share on other sites More sharing options...
Dnk Posted June 12, 2018 Author Share Posted June 12, 2018 It's not a 100 % accurate as every set up will vary but a ball park is near enough My Supra at 1.25 bar made 347 on a Dyno Dynamics hub dyno 18% = 410 24% = 430 Quote Link to comment Share on other sites More sharing options...
mattdavies Posted June 12, 2018 Share Posted June 12, 2018 It's not a 100 % accurate as every set up will vary but a ball park is near enough My Supra at 1.25 bar made 347 on a Dyno Dynamics hub dyno 18% = 410 24% = 430 At Surrey on Saturday mine made 416hp once corrected BPU Auto , when I asked Charlie what is made at the wheels he said 350hp so I would say that 18% is closer Quote Link to comment Share on other sites More sharing options...
The Raven Posted June 12, 2018 Share Posted June 12, 2018 My figures are very much the same id guess 18 being closer to Quote Link to comment Share on other sites More sharing options...
Chris Bailey Posted June 12, 2018 Share Posted June 12, 2018 Jheez, that makes dads car 850+bhp at the flywheel on E70. It made 708rwhp on Abbey Motorsports hub dyno. Never been sure on transmission losses though so normally stick to RWHP figure. Quote Link to comment Share on other sites More sharing options...
Sheefa Posted June 14, 2018 Share Posted June 14, 2018 Jheez, that makes dads car 850+bhp at the flywheel on E70. It made 708rwhp on Abbey Motorsports hub dyno. Never been sure on transmission losses though so normally stick to RWHP figure.Agreed with Chris. Mine made 753rwhp at Abbey and so I assumed 800 fly was a reasonable statement. Very similar figures at ProTuner bar 1 horsepower! Quote Link to comment Share on other sites More sharing options...
Guest Budz86 Posted June 15, 2018 Share Posted June 15, 2018 I'm going to disagree with you boys there; mine made 700 and 800 (pump and E60) at Abbey; with a 15% correction they would rise to 805 and 920. Much as I'd love to say I have a 900+hp car, it just isn't! Engine is out at the moment though and I'm thinking about having the engine dyno'd to see the difference. £100 says it doesn't get near 850.... Quote Link to comment Share on other sites More sharing options...
Chris Bailey Posted June 15, 2018 Share Posted June 15, 2018 I'm going to disagree with you boys there; mine made 700 and 800 (pump and E60) at Abbey; with a 15% correction they would rise to 805 and 920. Much as I'd love to say I have a 900+hp car, it just isn't! Engine is out at the moment though and I'm thinking about having the engine dyno'd to see the difference. £100 says it doesn't get near 850.... Also worth noting you have the 6466 same as us and Greg, that’s rated to 900bhp by Precision. Quote Link to comment Share on other sites More sharing options...
Sheefa Posted June 15, 2018 Share Posted June 15, 2018 Yeah to be fair I'll always work on rwhp. Car is going to Greg @ ProTuner for a few tweaks end of month as I have removed exhaust restriction and getting it mapped at 60% ethanol if possible. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted June 15, 2018 Share Posted June 15, 2018 On big power and torque engines through a stock transmission designed for a lot less the losses can rise alarmingly, alongside the friction loss heat generated, so 22 to 25% is entirely possible on mega power engines on stock transmissions (including the rear axle and driveshafts, which if overloaded become less and less efficient as things distort). Engine dynos rule Quote Link to comment Share on other sites More sharing options...
Lee P Posted June 16, 2018 Share Posted June 16, 2018 At Surrey on Saturday mine made 416hp once corrected BPU Auto , when I asked Charlie what is made at the wheels he said 350hp so I would say that 18% is closer A Dyno dynamics doesn't have a correction value for an auto so just assumes the car is manual and gives same correction. Quote Link to comment Share on other sites More sharing options...
mattdavies Posted June 18, 2018 Share Posted June 18, 2018 A Dyno dynamics doesn't have a correction value for an auto so just assumes the car is manual and gives same correction. So does that mean the correction figure would be higher ? Quote Link to comment Share on other sites More sharing options...
bayside_supra Posted June 20, 2018 Share Posted June 20, 2018 Wow these are way higher losses then I thought! I’m sure I read somewhere it was 12% for a manual. Mine made 635hp at the rear hubs so have always figured it was around 710hp at the flywheel. That’s what I tell people anyway lol Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted June 20, 2018 Share Posted June 20, 2018 The only way to find out is test the engine and ancillaries on their own on a decent engine dyno, then re-test in the vehicle on a hub dyno. A drum type dyno will show higher losses still as road tyres have a considerable power absorption when transmitting a lot of torque, less so at cruise. Quote Link to comment Share on other sites More sharing options...
bayside_supra Posted June 20, 2018 Share Posted June 20, 2018 Mine was done on a hub dyno. Less losses on one of those I guess? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted June 20, 2018 Share Posted June 20, 2018 (edited) Only no tyre losses and a means of applying a constant load, not flash readings as from an inertia dyno, which are very flattering as the engine can't stabilise. Any dyno is only as good and honest as its operator. Some are like statisticians and can supply any figures you may wish to see... My Skyline was sold to me with 430 BHP at the rear wheels read out from a rolling road dyno. I had the chance to nail it on an engine dyno before I started work on it and it was actually 305 from memory at the FLYWHEEL and after a few tweaks to the map to get the top end fuelling and timing something like Well under 300 "as was" and likely to fail on a circuit. Engine dynos can cause some disappointment! Edited June 20, 2018 by Chris Wilson (see edit history) Quote Link to comment Share on other sites More sharing options...
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