9 replies to this topic

[dandywarhol]

Any of you chaps/chapesses know the actual rev limit of a 3VD ECU? I know the 4TX hits near 10,000 but I'm interested in the 3VD limit

 

TIA, Alan

[JBX]

According to the advance ignition chart of the TCI, it is also 10,000rpm.

 

I guess the connecting rods bushes also act as a rev limiter but at a lower rpm...

[Studley Ramrod]

The MZ guys use the 3vd box to up the rev limit on their bikes, they reckon the unit limits revs to 8400rpm.

 

http://www.mzriders.....php?f=3&t=6564

[dandywarhol]

The MZ guys use the 3vd box to up the rev limit on their bikes, they reckon the unit limits revs to 8400rpm.

 

http://www.mzriders.....php?f=3&t=6564

 

That's why I'm asking Studley - I've got a Yamaha SZR660, same engine but I don't believe the info. I'm doing some light tuning to the engine and want to be able to allow it to rev a little higher than 7250. I might just get an Ignitech programmable unit for it...........Unless some kind individual would like to warm up their 3VD and wind open the throttle to see what the rev counter shows when the cutout cuts in..........?? 

 

Edited by dandywarhol, 22 October 2015 - 08:40 pm.

[LordZed]

I'm game 👍 I've hit it once on accident, and want to say it was around 9500, but I'll test it again to see where it cuts in.

[Studley Ramrod]

That's why I'm asking Studley - I've got a Yamaha SZR660, same engine but I don't believe the info. I'm doing some light tuning to the engine and want to be able to allow it to rev a little higher than 7250. I might just get an Ignitech programmable unit for it...........Unless some kind individual would like to warm up their 3VD and wind open the throttle to see what the rev counter shows when the cutout cuts in..........?? 

Yeah, it did read a bit confusing, possibly summat to do with where the ignition timing is set. Couldn't you just try borrowing one and seeing what happens ? I can lend you mine in a month or so when I start fixing my gearbox, if you can wait that long ?

Or maybe someone on here has one to lend you ?

[dandywarhol]

If someone has one to try I'd be grateful to them. Lord Zed - it won't damage the engine, it's why they are limited after all, and I'd be interested to hear your results.

If it is as high as 9500 it doesn't mean that I'd be using 9500 but if it lets me occasionally dip into the 8s that would be handy, especially after a bit of light tuning work.

 

It was just dipping into the 7000 range in 5th on the trackday.

 

Thanks for your input folks

[LordZed]

I took it to 9500 and it didn't cut in. I didn't have the nerve to go past that, though it was still pulling hard. 

[dapleb]

I thought this was discussed afore and the general consensus was there was no limiter on 3vd?

[dandywarhol]

Good man LordZed - thanks for that. Don't see why there wouldn't be a limiter if the machine has an ECU. I'd also say that if the Factory set the limit at 10,000 on the 4TX, then that's a safe limit - they wouldn't set a limit that is going to damage both the engine and their reputation