Matt Harwood Posted April 9, 2006 Share Posted April 9, 2006 I popped over to Rebas tuning today as there was a mini meet and a couple of guys were getting their cars dyno'd What was interesting was that two virtually identical NA's were being dyno'd. One auto and one manual. Both cars had performance exhausts, one RSR, the other a Blitz Nur. Both cars had stock airboxes, but one had an aftermarket panel filter. They dyno'd at 162 and 168 rwhp. (The manual being the higher). That's only about 3.5% difference! I was expecting slightly more than that... Thanks to the guys at Rebas for entertaining us. Very nice guys, and very helpful. Quote Link to comment Share on other sites More sharing options...
ChrisSZ Posted April 9, 2006 Share Posted April 9, 2006 :) :) Quote Link to comment Share on other sites More sharing options...
bromy Posted April 9, 2006 Share Posted April 9, 2006 That seems very low for the N/A, I thought they were around the 185-190 mark Quote Link to comment Share on other sites More sharing options...
chilli Posted April 9, 2006 Share Posted April 9, 2006 that is suprisingly close, but since bhp varies between the same spec car anyway, it's hard to use that one result as anything more than a rough guestimate, the auto could have been more powerful at the fly... Also, maybe the loss is non-linear and more noticeable at higher powers. Either way crazy 25% losses are probably only ever invented for pub bragging flywheel figures lol but, thinking about it, with a supposed 220bhp at the fly, that is around 25% losses! Surely that can't be right, maybe they were both down on power? Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted April 9, 2006 Author Share Posted April 9, 2006 From what I've seen of auto NA's on dynos before, I'd say the figures were about right. Although I agree that every engine is different and one can easily be more powerful than another... Quote Link to comment Share on other sites More sharing options...
Dave F Posted April 9, 2006 Share Posted April 9, 2006 From what I've seen of auto NA's on dynos before, I'd say the figures were about right. Although I agree that every engine is different and one can easily be more powerful than another... Bugger does that mean mine is lower than it should be? I was the manual n/a putting out 168 Quote Link to comment Share on other sites More sharing options...
Gazboy Posted April 9, 2006 Share Posted April 9, 2006 Bobbeh's stock UK6 at G-force was 268rwhp, vs my 250rwp stock JDMa at SRR (comparable dyno's) if that helps. Quote Link to comment Share on other sites More sharing options...
Prof. Monkey Posted April 9, 2006 Share Posted April 9, 2006 Perhaps the Dyno was slightly out, dont Supra's need a special setting or something? Quote Link to comment Share on other sites More sharing options...
ChrisSZ Posted April 9, 2006 Share Posted April 9, 2006 Bobbeh's stock UK6 at G-force was 268rwhp, vs my 250rwp stock JDMa at SRR (comparable dyno's) if that helps. Both turbos - no help:) Perhaps the Dyno was slightly out, dont Supra's need a special setting or something? LOL:d Quote Link to comment Share on other sites More sharing options...
bromy Posted April 9, 2006 Share Posted April 9, 2006 http://www.mkivsupra.net/vbb/showthread.php?t=51663&highlight=n%2Fa+dyno http://www.mkivsupra.net/vbb/showthread.php?t=3111&highlight=n%2Fa+dyno Quote Link to comment Share on other sites More sharing options...
michael Posted April 9, 2006 Share Posted April 9, 2006 What sort of power did the MR2 put out Matt? Quote Link to comment Share on other sites More sharing options...
Bobbeh Posted April 9, 2006 Share Posted April 9, 2006 That seems very low for the N/A, I thought they were around the 185-190 mark Thats what my mates S2000 with exhaust put out on a dyno, and they're rated at 240bhp. Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted April 9, 2006 Author Share Posted April 9, 2006 It's a Dyno-Dynamics rolling road. Personally, I like the figures from these machines as they seem to be more realistic. You can't compare dyno results from different makes of machine. G-force use Dyno-Dynamics rollers, and I've always found their figures to be quite reliable, so as Bob said, the S2000 would be closer to the 190 mark. I know people prefer to see higher numbers. Personally, I'd rather quote a lower figure Nick, it'd be great to see your NA-T on the dyno. Fancy a trip to Medway? Quote Link to comment Share on other sites More sharing options...
ChrisSZ Posted April 9, 2006 Share Posted April 9, 2006 As Ian (from Rebas) said, it doesn't mean anything on the dyno - it's on the road (and with the right driver) where it actually counts!! (still makes mine comparatively slow though ) Quote Link to comment Share on other sites More sharing options...
bromy Posted April 9, 2006 Share Posted April 9, 2006 Nick, it'd be great to see your NA-T on the dyno. Fancy a trip to Medway? I'd love to get it back on the rollers but the clutch is now on it's way out, think I'm going for the RPS 6 puck.... last time I had it on the rollers it gave 283RWHP @ .4bar and that was before all the latest work has been done Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted April 9, 2006 Author Share Posted April 9, 2006 I'd love to get it back on the rollers but the clutch is now on it's way out, think I'm going for the RPS 6 puck.... last time I had it on the rollers it gave 283RWHP @ .4bar and that was before all the latest work has been done Where/what rollers was than on Nick? Don't talk to me about bloody clutches! Quote Link to comment Share on other sites More sharing options...
bromy Posted April 9, 2006 Share Posted April 9, 2006 I think the standard cams work quite well Quote Link to comment Share on other sites More sharing options...
ChrisSZ Posted April 9, 2006 Share Posted April 9, 2006 ............except for the spot around 4,500 - 4,800rpm!! Showed up exactly the same on both mine and Adams! Was it there on yours too Dave?? Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted April 9, 2006 Author Share Posted April 9, 2006 Yeah, you could see the power increase on the NA plots today too. Should be an even steeper power curve with your car now Quote Link to comment Share on other sites More sharing options...
Dave F Posted April 9, 2006 Share Posted April 9, 2006 ............except for the spot around 4,500 - 4,800rpm!! Showed up exactly the same on both mine and Adams! Was it there on yours too Dave?? Yes mate Quote Link to comment Share on other sites More sharing options...
JohnA Posted April 10, 2006 Share Posted April 10, 2006 ...They dyno'd at 162 and 168 rwhp. (The manual being the higher). That's only about 3.5% difference! I was expecting slightly more than that.... It's mainly the TC losses with the fluid going around and producing nothing more than extra heat. But if you think about it, if the difference was (say) 30rwp, then all that extra heat would eventually boil the autobox, wouldn't it? Can you imagine getting rid of the extra heat created by a 20+KW heater in the transmission? There would have to be noisy fans running all the time just to stop the thing from self-destructing after a few minutes idle, wouldn't there? Quote Link to comment Share on other sites More sharing options...
chilli Posted April 10, 2006 Share Posted April 10, 2006 It's mainly the TC losses with the fluid going around and producing nothing more than extra heat. But if you think about it, if the difference was (say) 30rwp, then all that extra heat would eventually boil the autobox, wouldn't it? Can you imagine getting rid of the extra heat created by a 20+KW heater in the transmission? There would have to be noisy fans running all the time just to stop the thing from self-destructing after a few minutes idle, wouldn't there? It's not going to be generating any heat on idle is it, the heat due to losses would be proportional (roughly) to the power put through it, so only at max power. Also, although the TC is probably the worst offender, some of the losses must be shared with the auto box iteslf, not sure what the ratio would be. I'd imagine a good starting point would be to say the auto and manual box are about the same, and the TC adds some additional losses on top (so it's only some fraction hence no boiling up!) also, the TC is a bit like a huge heatsink / fan isn't it spinning at a fair speed, there is a lot of surface area to get rid of the heat, some probably goes into the geabox and crank too... I wouldn't fancy touching it after a flat out blast though, bet it does reach a fair old temp!!! Quote Link to comment Share on other sites More sharing options...
JohnA Posted April 10, 2006 Share Posted April 10, 2006 It's not going to be generating any heat on idle is it, ... It is. That's why you have to press the brake while you are stopped and in "D". This friction that the brakes have to overcome is roughly the engergy wasted by the TC on idle. Worth a few bhp. the heat due to losses would be proportional (roughly) to the power put through it, so only at max power... It's more like X + Y(Power) X = idle losses Quote Link to comment Share on other sites More sharing options...
paul gtir Posted April 10, 2006 Share Posted April 10, 2006 dont forget you get a est 14% transmishion loss Quote Link to comment Share on other sites More sharing options...
ChrisSZ Posted April 10, 2006 Share Posted April 10, 2006 I thought transmission losses were higher??? Quote Link to comment Share on other sites More sharing options...
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