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diff gears in relation to dyno output result

ari666

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ok, so from old mates calculation,

197.8= ( A x 5900) 5252

A= 176.075 flbs @ 5900rpm? seems pretty damn low... 238 NM ... weird since a stock VK black is supposed to produce [email protected]

but wait.. for that calculation to work, i would need to know peak rpm for torque???? i only know peak rpm for KW. how does that work?>???
 
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ari666

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ok, now i am full of question marks.

how can it be, that if torque is the ONLY figure really being calculated, HP will quite often go up the rev range quite a lot further. random internet example pics:







a lot of the dyno sheets i have looked at, the torque is completely unrelated to the HP curve. torque generally peaks early and peters off, whereas HP keeps climbing.
 

HRT 666

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Thats because HP = torque X rpm so even if the torque starts to drop off slightly but the rpms continue to climb the HP will continue to climb also.
Only if the torque drops off at a large rate as the rpms climbs then the HP will feather off.
Make sence now?
The torque curve will never be UNRELATED to the HP curve as without torque and rpm you will have NO HP.
 

ari666

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that makes no sense at all.

so then given my calulation (if i have done it correctly) you saying that somehow i have managed to make the power (KW) increase dramatically over stock, but make the torque decrease ASTRONOMICALLY

ill drop the stats again for those that cbf reading

147.5 RWKW
197.8 HP
176.075 ftlbs torque
 

HRT 666

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No that is NOT what I said. For you to end up with any increase in power you will HAVE to have an increase in torque at the same rpm as before.
As it just wont happen with out the torque (unless you kept the same torque and doubled the rpm) and that would not of happened.
Put up the before and after dyno sheets.
 

old mate

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HRT's got it. look at this for an example, using the EVO X dyno sheet.

3650 rpm there is near on 320 lb/ft.
(3650 x 320)/5252 = 222.3914 hp

but later on when the torque tapers back to about the same level as before, but at higher rpm it works like this:

5600 rpm and close to 320lb/ft.
(5600 x 320)/5252 = 341.2034 hp.

so the only reason the power figure has gone up is because the torque figure is made at a higher rpm.
 

VT-565

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Go to the drag strip.

If it pulls the wheels after a warmup, its got enough torque
 

old mate

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ok ari666, i just checked out your dyno sheet. lets do some calculations here to work out whats going on.

its pretty blurry so my numbers wont be 100% spot on. so bear with me.

first lets pic some spots in the rpm range. i might as well do every 200 rpm and then make a graph in microsoft excel. would help my statistics study haha.

im converting from kw to hp at 1.341hp per kw.

2800 = 85.854hp (64kw)
3000 = 100.575hp (75kw)
3200 = 109.962hp (82kw)
3400 = 120.69hp (90kw)
3600 = 135.441hp (101kw)
3800 = 147.510hp(110kw)
4000 = 156.897hp (117kw)
4200 = 162.261hp (121kw)
4400 = 171.648hp (128kw)
4600 = 174.330hp (130kw)
4800 = 182.376hp (136kw)
5000 = 187.740hp (140kw)
5200 = 190.422hp (142kw)
5400 = 189.082hp (141kw)
5600 = 191.763hp (143kw)
5800 = 197.127hp (147kw)
5900 = 197.7975hp (147.5 kw)

alright, so we have all the hp figures and rpms for every 200rpm from 2800 to 5900.
if we apply the formula “torque = (5252 x HP) / rpm” to each of these we can work out the torque at each spot. here goes.

Im converting ft/lb to nm by multiplying by 1.356

2800 = 85.854hp (64kw) 161.0376 ft/lb 218.3670 nm
3000 = 100.575hp (75kw) 176.0733 ft/lb 238.7554 nm
3200 = 109.962hp (82kw) 180.4751 ft/lb 244.7243 nm
3400 = 120.69hp (90kw) 186.4306 ft/lb 252.7998 nm
3600 = 135.441hp (101kw) 197.5934 ft/lb 267.9366 nm
3800 = 147.510hp (110kw) 203.8743 ft/lb 276.4536 nm
4000 = 156.897hp (117kw) 206.0058 ft/lb 279.3438 nm
4200 = 162.261hp (121kw) 202.9035 ft/lb 275.1372 nm
4400 = 171.648hp (128kw) 204.8853 ft/lb 277.8245 nm
4600 = 174.330hp (130kw) 199.0394 ft/lb 269.8974 nm
4800 = 182.376hp (136kw) 199.5497 ft/lb 270.5894 nm
5000 = 187.740hp (140kw) 197.2021 ft/lb 267.4060 nm
5200 = 190.422hp (142kw) 192.3262 ft/lb 260.7944 nm
5400 = 189.082hp (141kw) 183.8898 ft/lb 249.3681 nm
5600 = 191.763hp (143kw) 179.8463 ft/lb 243.8716 nm
5800 = 197.127hp (147kw) 178.5019 ft/lb 242.0486 nm
5900 = 197.7975hp (147.5 kw) 176.0733 ft/lb 238.7554 nm

ok so now we have all the data as an estimate of your rear wheel output. i might make some pretty graphs in a sec for it. i must say though, your engine doesn't have heaps of torque.
 

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