Discussion
After some serious blatting at Duxford, a comment from my engine builder "you might find a rev limmiter handy" came to mind. Anyone done this? Also can a gear change light be incorperated, say an LED run up the trim around the screen about eye hieght.
He said the chip should sort the rev bit but belt and braces cheaper than another re-build etc.
He said the chip should sort the rev bit but belt and braces cheaper than another re-build etc.
My 390 has a 'Smoothcut RL8 Visi-scale' adjustable limiter by Micro Dynamics. Two wires to the coil, one to the battery. Set anywhere from 4500 to 7500 RPM.
Cost the previous owner about 60 quid I think. At the moment mine is at 5200rpm; this actually kills the sparks around 5000 so there's evidently a slight inaccuracy somewhere. My tacho is spot-on when checked with a hand-held strobe that we have at work, at least over part of the rev range anyway. I wouldn't be popular if I laid on 5000 RPM in the car park.....;-)
Ian
Cost the previous owner about 60 quid I think. At the moment mine is at 5200rpm; this actually kills the sparks around 5000 so there's evidently a slight inaccuracy somewhere. My tacho is spot-on when checked with a hand-held strobe that we have at work, at least over part of the rev range anyway. I wouldn't be popular if I laid on 5000 RPM in the car park.....;-)
Ian
quote:
Thanks. Will try to locate on the web. Deemon Tweeks?
I am assuming that at 5000 revs I am pretty much max power so 200 or so difference will not matter. Just crank it up a bit. Nice to know if it has a function to spark up a light/led.
You mean you don't have a dyno curve? You have a hybrid 218 cam don't you. That peaks at around 6000+ rpm when setup (it is on the Griff 500) so changing at 5000 or so is a bit of a waste?
I use the OMEX system on the 520 pre big engine. Worked fine. Set the gear shift to be 2-300 revs before the redline of 6250.
steve
www.tvrbooks.co.uk
quote:
You mean you don't have a dyno curve? You have a hybrid 218 cam don't you. That peaks at around 6000+ rpm when setup (it is on the Griff 500) so changing at 5000 or so is a bit of a waste?
I use the OMEX system on the 520 pre big engine. Worked fine. Set the gear shift to be 2-300 revs before the redline of 6250.
steve
www.tvrbooks.co.uk
Having to move at the time ment the dyno bit was left out for speedy return of the car. No storage at the rebuild and I was moving some distance away.
Upshot I think, I will speak to him again about max revs but still have one (limiter)
At Duxford I was about 5000 rpm on change ups. Seemed to work fine.
quote:
Have you seen this
http://ourworld.compuserve.com/homepages/shpub/wcat22.html
GF.
Often drooling for bits on there and missed it.
Cheers.
It will work fine but it is considerably slower if the car's peak power is around 6k mark. This is why having a dyno curve is all important if the engine is nowhere near standard as it determines the best chnage up points and strategy.
Without seeing a dyno curve, I think it could be a bit of waste having a fast road 218 cam if the engine can't be revved to take advantage of its characteristics. But as other factors can affect the torque curve, it would be difficult to guess and changing early at least protects the engine. I have to say it doesn't sound normal to me. Getting a dyno session could be very worthwhile to understand what the engine does.
Steve
Without seeing a dyno curve, I think it could be a bit of waste having a fast road 218 cam if the engine can't be revved to take advantage of its characteristics. But as other factors can affect the torque curve, it would be difficult to guess and changing early at least protects the engine. I have to say it doesn't sound normal to me. Getting a dyno session could be very worthwhile to understand what the engine does.
Steve
We were pushed for time with the move etc so the dyno bit was the only way to save time. Still got a warranty though. I asked him about the dyno bit and he said "does it go fast?"
After Duxford, its fast.
Doesn't a dyno session mean engine out?
I trust the guy who built the engine. 5000 is not a figure he mentioned, just one I am sticking to at the moment as its cheaper than another rebuild.
After Duxford, its fast.
Doesn't a dyno session mean engine out?
I trust the guy who built the engine. 5000 is not a figure he mentioned, just one I am sticking to at the moment as its cheaper than another rebuild.
A rolling road would be good enough so that you can see where the peak power/torque is and so on. The car may seem fast but it may not be as fast as it should be especially with that cam which tends to have its peak power/torque higher up the rev band.
As you say you are taking the sensible approach which is definitely the right thing to do.
As you say you are taking the sensible approach which is definitely the right thing to do.
I'd expect even a standard Rangey 3.5 to rev past 5000 without too much grief! My 390 has a fast road cam in and pre-rebuild I saw 6000 a few times through the gears. At the mo I'm playing safe, but you can tell the power's there.... in fact I think I'm killing it before the full urge by having 5200 up!
Ian
Ian
As I said, will be done. In the garage (sleeping) as it needs new shoes on the front again.
Will have a look at ACT as well but one needs fitting.
Need to do a few things, tyres first (legal) limiter next I hope. Shift light bit I hope is not too tecnal. All in package.
Delay prompted by holiday needed, and funds tend to get eaten by UK destinations. Cornwal week after next in the festa unless missis can be persueded otherwise.
Will have a look at ACT as well but one needs fitting.
Need to do a few things, tyres first (legal) limiter next I hope. Shift light bit I hope is not too tecnal. All in package.
Delay prompted by holiday needed, and funds tend to get eaten by UK destinations. Cornwal week after next in the festa unless missis can be persueded otherwise.
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