Justin Posted August 28, 2003 Share Posted August 28, 2003 Just booked my first dyno session with Pete Betts at Santa Pod. As I am a dyno virgin and will be racing down the track later I had a few questions. What revs do they need to get up to for getting the readings - red line? Do they floor the accelerator or is it just a steady push? Anyone know the percentage bhp loss at the wheels of a J-spec Ta. J.:flame Dev Quote Link to comment Share on other sites More sharing options...
Alex Posted August 28, 2003 Share Posted August 28, 2003 They use half the rev range and make the rest up, whilst only using 1/2 throttle to keep the loads low.... 30% on an Auto I believe Quote Link to comment Share on other sites More sharing options...
Thorin Posted August 28, 2003 Share Posted August 28, 2003 less than that I would have thought, I saw an estimate for a 27% transmission loss for a Skyline with all their 4wd electronic drive itself gubbins 20-25% for an auto? Quote Link to comment Share on other sites More sharing options...
Need4Speed Posted August 28, 2003 Share Posted August 28, 2003 J-spec Auto reckoned to be about 25%. In other words add 33% for a guideline flywheel figure. Quote Link to comment Share on other sites More sharing options...
Mark Ayling Posted August 28, 2003 Share Posted August 28, 2003 Pete dynoed my car at Billing and he basically put it in fifth and floored it right up to the red line, although he did ask me first how high I wanted to take it - of course I wanted him to cane it to get maximum power output, although in reality the power/torque drops at the top of the revs range anyway.... HTH. Quote Link to comment Share on other sites More sharing options...
Mark Ayling Posted August 28, 2003 Share Posted August 28, 2003 Bah - just noticed yours is an auto, not sure how relevant my last post is... Quote Link to comment Share on other sites More sharing options...
Adam W Posted August 29, 2003 Share Posted August 29, 2003 33% driveline loss? That sounds WAY too high to my uneducated ears! I thought it was about 15% for a manual and 20% for an auto. Quote Link to comment Share on other sites More sharing options...
THOR Racing Posted August 29, 2003 Share Posted August 29, 2003 always ask the person doing it put it in fifth and floored it right up to the red line For most manual cars the top gear is an overdrive gear and thus the previous one is normally the 1:1 drive (so 5th for a 6 speed and 3rd for a 4 speed). For auto's I hold them in Drive "D". On the Supra it's easy as we can use the Manual mode to hold the gears. Most other makes of auto are terrible, the power runs are flipping hard to get anything sensible out of as they keep changing gear all the time. We then take a steady control run at 2000rpm to synchronise the Dyno RPM to the car RPM. i.e. work out the rear differential gear ratio if it's unknown. Normally somewhere between 3.8 and 4.2 for most cars. We can make a power run over any RPM range we like. Normally I choose to start the runs at 2000rpm and end at beginning of red line or 500rpm before. So say 6500 or 7000rpm etc. I always ask the owner first if they have a preference. Normally THEY say just "drive it like you stole it". The runs aren't the same as you get on the road as I also program in how long the power run should take. I could do a run over 100s if I wanted for example. Normally I choose 8s There is a settling period of 4s before the run begins (again I choose this) So it's a controlled power run and if I set 4000rpm to be your maximum RPM for the run no matter what you or I do it will NOT go above that. So if you aren't happy to hit the rev limiter (which I prefer not to) then I can set this 500rpm below. (or whatvever) As Mark says, most cars have aleady reached their max power before rev limiter anyway. So no point. I hope that helped. 33% driveline loss? That sounds WAY too high to my uneducated ears! I thought it was about 15% for a manual and 20% for an auto. Edit: This is exactly why we NEVER give you a printout for Flywheel power and ALWAYS give a figure at the wheels. That way you CAN compare a manual Supra with an auto one. If people ask I always use the stock answer of 20% and explain we are not prepared to argue about flywheel power and it's just a guess. Regards Pete Quote Link to comment Share on other sites More sharing options...
Need4Speed Posted August 29, 2003 Share Posted August 29, 2003 33% driveline loss? That sounds WAY too high to my uneducated ears! I thought it was about 15% for a manual and 20% for an auto Not 33% loss, add 33% which is 25% loss. The source of this figure, which is approximate, was a highly respected race engineer and MOTEC specialist at a RR many of us have used. Quote Link to comment Share on other sites More sharing options...
Justin Posted August 29, 2003 Author Share Posted August 29, 2003 Great info Pete thanks. Think I'll go for the 500 below redline on the day:eek: So what are we saying then? If I get e.g. 290 at the wheels that would be 348bhp at the crank using a 20% addition? Quote Link to comment Share on other sites More sharing options...
Adam W Posted August 29, 2003 Share Posted August 29, 2003 Originally posted by John Packham Not 33% loss, add 33% which is 25% loss. The source of this figure, which is approximate, was a highly respected race engineer and MOTEC specialist at a RR many of us have used. I understand what you mean now John. It's power at the wheels that moves you down the road though, life would be a lot easier if everyone quoted that! Quote Link to comment Share on other sites More sharing options...
THOR Racing Posted August 31, 2003 Share Posted August 31, 2003 So what are we saying then? If I get e.g. 290 at the wheels that would be 348bhp at the crank using a 20% addition? If you want an IDEA on flywheel power then yes, but I say 20% to eveyone, no matter what the car. As I said before I don't want to get drawn into an argument I cannot prove. BUT it's far easier if we all quoted power at the wheels, then there would be no argument in comparison. (except the rolling road used of course..... as always ) Regards Pete Quote Link to comment Share on other sites More sharing options...
Wez Posted August 31, 2003 Share Posted August 31, 2003 Hey Pete, Do you have a charge for say an hour of use for tuning purposes, is your setup able to monitor and display AFR throughout the run? Regards Wez :flame Dev Quote Link to comment Share on other sites More sharing options...
THOR Racing Posted September 1, 2003 Share Posted September 1, 2003 The Dyno measures.... TORQUE at the wheel hubs, Calculates the POWER at the hubs, manifold PRESSURE , air inlet TEMPERATURE (depending on where you put the probe, could be air filter, intercooler, radiator etc etc) AIR FUEL RATIO (or Lambda) with a Bosch LSU wideband O2 sensor. You get all this in just a power run Fees are as follows.... Fixed fee Dyno Run (£60), you get max of 6 consecutive runs. Dyno tuning/diagnostic work (£100/hr) All Mechanical and Electrical labour (£40/hr) Paid up club members get 10% off all labour and dyno rates (not parts! and not at shows.) Club bookings get 15% We have a 3000sq ft warehouse for mechanical modifications and electrical equipment installation. We can fit anything from exhausts, air filters to CAMs and engines. We can also fit any electrical tuning gadget, APEXi, HKS, Blitz etc including full replacement engine management units. These can all be programmed using the precision of our Chassis Dynamometer (1600BHP and 4400ft/lb torque). Finally we are based in North Coventry and hope to see some more Supras Regards Pete Quote Link to comment Share on other sites More sharing options...
Wez Posted September 1, 2003 Share Posted September 1, 2003 Hey Pete, Thanks for the info. Does the tuning price stay at 100/hr even if its not yourselves doing the tuning? Regards Wez :flame Dev Quote Link to comment Share on other sites More sharing options...
THOR Racing Posted September 1, 2003 Share Posted September 1, 2003 Does the tuning price stay at 100/hr even if its not yourselves doing the tuning? It does as you have still got the operator controling the dyno and your car is still preventing other cars from using it. So whether you do it or us, it's still sitting on the dyno. Remember you get 10% off (i.e. £90 /hr) if you've become a paid up member of the club. We are also doing a bonus scheme, where the more you use us the more discount you get. Up to the max of 15%. So for each visit you get an extra 1% off. So 5 trips being a member of a club gets you to 15%. Which you now receive for life. Obviously a non-club member would take 15 trips to get 15% and ALL show events are at 15% discount anyway, hence no extra discount available on the show days. Regards Pete Quote Link to comment Share on other sites More sharing options...
Wez Posted September 1, 2003 Share Posted September 1, 2003 Thanks Pete, Prices are pretty good and as i am a member even better We have done most of the mapping on the road and its running very nice at the moment but for fine adjustment we will need to use a rolling road and yours sounds pretty damn good. I think my local rolling road cannot take supra power Are you open saturdays? Regards Wez Quote Link to comment Share on other sites More sharing options...
THOR Racing Posted September 1, 2003 Share Posted September 1, 2003 Are you open saturdays? If we have the work then yes. So we will open for a booking, but not normally at present. Please ring to book a day though as we have a lot of shows this summer and weekends are therefore busy already. Regards Pete Quote Link to comment Share on other sites More sharing options...
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