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union7

Gray Wire Dyno

16 posts in this topic

Here is a dyno showing the difference between power curves on our engine dyno, with the Gray wire cut & uncut.

The actual power numbers are not directly comparable to other dynos, however at a later date I will put a CRF 450 r and a drz400e on the same dyno, with the same calibration factors as a reference.

The bike was a 2004 WRF with stock can, insert removed,no other mods other than a stainless heade pipe we made wich is an exact copy of the stock Ti one, except for the addition of an O2 bung.

http://www.flickr.com/photos/28457267@N08/2650745039/

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its really hard to see but that yellow line is right above there. Ive always wondered the difference with it disconnected. Thanks for the info :thumbsup:

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so what is this telling me? The way I read it. Stock has a better bottom, but at 6k + RPM you get more mid-top end power. Am I reading that right?

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The YZ and WR curves seem pretty much the same until ~6500 rpm. Hard to follow the curves back to the lower rpms as there are too many of them.

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I am looking at it from the perspective that the Hp and torque right through the rev range are much smoother, ie. no humps or hollows.

This is fascinating stuff union7, thank you !!!

Ok, there's not much difference in either outright HP or torque output, but when you consider that this is purely a result of differences in ignition timing (not hot cams , exhausts, etc. etc.) it is quite a marked difference over stock.

Thanks again union7. Great stuff!!! :thumbsup::p

Greg

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thanks. pretty much confirms what I thought I felt. basicly the engine stops building HP after 6K, except I thought it took a dump at 8K not at 6K. its total lameness on hill climbs. unplug the grey wire and its a hillclimbing monster.

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the MAJOR difference is in the range with the arrows, no significant difference below and above it. about 6500-9000 rpm

i would disregard the dark red hp line and it's black tq line, that run was probably a "bad" pull. don't let that confuse you.

has any one confirmed that the ignition really has to be off (then on)to disconnect/connect the gray wire and have it switch curves?

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the MAJOR difference is in the range with the arrows, no significant difference below and above it. about 6500-9000 rpm

i would disregard the dark red hp line and it's black tq line, that run was probably a "bad" pull. don't let that confuse you.

has any one confirmed that the ignition really has to be off (then on)to disconnect/connect the gray wire and have it switch curves?

What I find interesting is by just doing the gray wire mod the WR is now making YZ type power (~55hp). Gotta wonder what the bike would make with an open YZ style exhaust and YZ cam and the gray wire mod!:thumbsup:

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union7; thanks for these results. Very informative.

One thing that struck me as very significant here is that while peak torque in both scenarios is basically the same (37.3 vs 37.8) in around the 6500-6750 rpm range, the delta in torque when peak hp of 55.9 is achieved at around 8284 is very important. With the grey wire cut, at peak hp, you will see that you get about 10% more torque (I'm guessing by the graph the low at 32.5 lbs and high at 36.0 lbs in around that 8100-8200 range).

I have no clue about your inquiry on whether or not you have to have the ignition off to switch the wire (assuming via a manual switch). I would expect you could test that on the dyno to proof it out.

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mmmm.. can't say if it is making YZ power really, I think the dyno is on the optimistic side.

can't really say how well calibrated the dyno is, it was more to show back to back differences..... , seat of pants, it's much faster than the KTM 450 '07EXC, I think I'll put the CRF 450R on the dyno tonight.

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What I find interesting is by just doing the gray wire mod the WR is now making YZ type power (~55hp). Gotta wonder what the bike would make with an open YZ style exhaust and YZ cam and the gray wire mod!:p

SXP , are you being sneaky and trying to get Union7 to do a bunch more testing for all us WR owners.:thumbsup: WR Dave

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SXP , are you being sneaky and trying to get Union7 to do a bunch more testing for all us WR owners.:thumbsup: WR Dave

Shhhh...:p

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Shhhh...:thumbsup:

yeah sure, i could be duped into testing any sample parts that are sent my way (duh), of course our shipping department is really bad at shipping out things that have been received......LOL

just dynoed a 250 KTM 2 stroke and a 2004 CRF 450R, so that should stir up all the brand loyal types....;-)

i'll post 'em soon.

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here is a dyno overlay with :

KTM 250 2 smoker 2008

2003? CRF 450R

2004 WR450

http://www.flickr.com/photos/28457267@N08/2653720231/sizes/o/in/set-72157606059852662/

keep in mind ,I know the jetting is pretty optimised on the WR, but I don't know about the other two yet. Also the KTM is brand new, but the other two don't even have new rings,i do know the valves are in spec, but not new.

just something to look at. i wouldn't get too carried away with the numbers.

it is interesting to compare peak numbers vs the total area under the curve 4strk vs two....

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