3000S rev limiter !

[duncscz]

Whilst putting my 3000S through it's paces on a rolling road, I was relatively pleased with 130bhp at 4300 rpm but then what appeared to be some form of rev limiter kicked in.
I have a Newtronic elect ign, which seems to work fine, east start-up etc. but nothing else non-standard.

Could the elect ign. have such a feature? Mind you, it could be a fault rather than a feature !
(I've not got an answer from Newtronic yet).

Maybe something else is the cause - lack of fuel perhaps?

Any ideas (or access to a datasheet for the Newtronic system?)

[davidy]

Fuel Starvation is the most likely cause, I had this on a rolling road at a similar rpm (4500). When the problem was cured it would run (much) higher.

Is that figure a calculated flywheel figure or an at the wheels figure?

If its at the wheels do not put normal unleaded in it without Octance booster as you have a trick engine!

davidy

[duncscz]

Hi Davidy,

Engine is nothing special - 130 was the flywheel calculated from a basic power of 104.
Any tips to cure the problem ? - time to fit an electric fuel pump and/or strip down the carb perhaps ?

[davidy]

Have a good look at the mechanical fuel pump, mine went (a) the inlet to it had become blocked and at a later date (b) went porous - not brilliant!

The problem was temporarily resolved by cleaning the inlet out and putting a fuel filter between tank and pump (I already had a filter between pump and inlet manifold - this was a pyrex glass filter so you could see the quality of the fuel).

When it became porous I replaced it with a blanking plate and put an electric pump on. (I happened to have a Kent 1600cc engine in the garage with a 'Ford' blanking plate on that just fitted (and an electric fuel pump!)

BTW It may be that the cam lobe driving the pump is worn, can you pull more revs on the road. If so I would just put it down to rolloing roaditis. TVRs can be very difficult on the rollers as everything gets so hot!

davidy

[duncscz]

All sorted. It was indeed the rather dirty fuel filter on the front of the carb - I was surprised the engine ran at all! Nothing to do with the elect ign., though Newtronic do have a version with rev limiter as it happens. Fitted an in-line filter as well, between tank and pump - first run afterwards - smoothly up to 5500 rpm!