Triumphrat

mikeinva · 12-08-2012, 08:12 PM

Quote:

Originally Posted by mike-tt special

thanks papa weeley
if you pause the video at 5:27 and look at the torque curve you'll see how strong the power delivery feels, it makes 50 lb/ft at 2500rpm rising to 60 lb/ft+ at 4000rpm then holding that to 7500rpm (basically it pulls just a hard whatever the rpm).
i think there is alot more to come when i fit the daytona 42mm throttle bodies

what size motor is that if its a 865 you need to find another dyno shop.

mike-tt special · 12-09-2012, 10:21 AM

sorry mike i thought everyone would realise it's 904cc.

yeh! those numbers from an 865 with 790 inlet cam and standard t b's would be crazy

correct me if i'm wrong mike(i'm sure you will lol) but looking at yours and others dyno graphs i don't think a 904 with 790 inlet cam,gasflow,2mm valves,36mm tb's and the D&D 2-1 would make more hp peak.also i would expect the same motor with the d&d 2-1 would have a big hole in the torque below 5000rpm.

mikeinva · 12-09-2012, 09:33 PM

well yes they will yours is in din hp so you dont have as much if it was in sae hp i think yours would be around 83 hp sae .But thats not bad.What i find hard to buy is 50 ft/lbs at 2500 no 904 can even do that heck most biigger motors wont .but that would go down to upper 40s ft/lbs in sae numbers but its still to high.A good 904 makes around 85hp and around 65 ft/lbs but they dont make alot of torque untill 4500 to 5000.will your bike lift the front wheel a foot of the ground if you wack the throttle in 1st gear at 2500?
If not your not makeing 50 ft/lbs at 2500.trust me I know this from much testing.

mike-tt special · 12-12-2012, 05:33 PM

ok for the sake of clarity and because this is a american forum i will use the sae scale from now on.

mike i don't see why you are quite happy to accept the dyno figures of 83hp peak and 60lb/ft peak but think there is something wrong with the lower part of the chart,
all thats happened is that due to better design my exhaust has filled the hole in the torque curve that the d&d 2-1 creates, if you know how to doctor certain areas of dynojet 250i charts your smarter than me or my dyno operator.

also for clarity the 904 power figures of 85hp and 65lb/ft torque that you quote mike i presume are for your 904(the one that you posted dyno charts for in the dyno thread) which has more engine mods than mine i.e 42mm mikuni(worth 5-10hp) and 813 cams(worth 5-10hp), so with the addition of 42mm tb's to my bike should put me around 88-93hp sae and the addition of 813 cams should put me around 93-103hp

by the way mike i risked life and limb to try the wheelie test in sub zero temperatures here but i did it at 3000rpm because that is where it makes 50lb/ft sae, and yes it does!.

mikeinva · 12-12-2012, 06:29 PM

its more a mater of not enough cc to get that much torque at low rpms.how could the dyno be off on torque?torque is figured by the tach signal on dynojet machines .hell i saw one on my bike once that said it made 110 ft/lbs lol i knew that wasnt right.I do agree if you are running stock tb you are getting about all it will do on top end.You maybe on to something with the pipes giveing you low end I cant say your not that is a very flat torque line .I am just saying i think it maybe reading alittle high.It doesnt mater though if you used the same dyno before and after you know you have gained thats all that really maters anyway.Look at it this way supose the dyno tach is off 500 to 1000 rpms then you would be in the 3500 to 4000 rpm range and that i would say was right.
Dont go by my dyno readings with the 42s as far as anything under 4500 I had the guy roll on the throttle slow I did not have acell pumps right back then.I dont care abou any thing under 5000 rpms on the dyno I am only looking for what main jets make the most hp .I set the low end up by what takes off the best on the road the dyno cant tell you that,you must go by feel and what the a/f gauge tells you.

mike-tt special · 12-13-2012, 09:13 AM

i see where you are coming from with the dyno tach reading 1000rpm low theory but since i have set my ecu rev limit at 8250rpm and that is where the dyno tach cuts there can't be any error there.

i think it's worth pointing out at this stage that steve hammond at motrac racing who did the dyno runs is a very experienced engine biulder/tuner and dyno operator(one of the first dynojet dynos in the uk). he has done development work for shell oil and engine biulding/tuning work for british superbike teams.