rev limiter legality

[FastDB2s]

Are rev limiters legal in historic racing

[terence]

Ran one on my B for years,scrutineers were always aware of what it was,no problems.

[Mike Bell]

I've not heard of a car failing legality checks for having one. Some organisers have different rules on acceptance of electronic ignition, but can't remember ever seeing any mention of electronic rev limiters......

[FastDB2s]

Thanks Mike, didn't think there were any rules on them but you have to ask

[John Turner]

Well, I'd rather see our cars survive to fight another day than get over revved and blow up and be out for the rest of the season!

[Rudernst]

I completely disagree !!

You need to look into Appendix K.
In there it clearly says that rev limiters are only legal if they work to the same principle as in period and which means not at all. That rules out reliable rev limiters in many forms of historic racing.

I think that this is a stupid and arcane rule that just puts engines at risk.
fundamental traditionalists at work again
nobody tries to go quicker by hitting the limiter on the upshift
yes, you might gain a Little at a start when you dont have look at your rev Counter with an eagle eye and have more overview of the General Situation but, so what

what is happening in the real world is that this rule is not policed and you will very likely not be bothered if you fit one.

buuuuuuut, most limiters are more trouble than they are worth, I stopped bothering with them years ago, many older ignitions dont really like them
On the other Hand, they are mandatory in HFO and work fine with the DFV spark box

Rudolf

[Dave Brand]

Originally Posted by Rudernst

In there it clearly says that rev limiters are only legal if they work to the same principle as in period and which means not at all.

Lotus Twincams had a mechanical rev limiter in period, built into the rotor arm. I believe other cars, e.g. Rover P6, VW, may have used a similar device.

[simon drabble]

I agree with Rudolf, whenever I have had one fitted it has ended up causing problems. It won't protect you on a dodgy downshift and on the way up you should have some concept as to when to change!

[John Turner]

I have to say that I am very confused by a couple of posts here! Are you supporting the use of RELIABLE limiters or not? All I was saying is that I would prefer our FISCAR cars not to be over revved to ensure their survival from one race to the next by whatever means works.

(Rudolf - emailed you about the FLIERS ages ago and Combe on 6th October!)

[simon drabble]

I dont have a problem with people using them - just I think they can cause more problems than they solve.

[Mike Bell]

Originally Posted by Dave Brand

Lotus Twincams had a mechanical rev limiter in period, built into the rotor arm. I believe other cars, e.g. Rover P6, VW, may have used a similar device.

It used the increase in centrifugal force as revs increased to break the HT connection, IIRC!

Rudolf is correct of course- there is a specific mention in AppK for Period E, F and G1 Series Production Touring and Standard Grand Touring Cars- "The addition of an electronic ignition system is not permitted, nor is that of an electronic rev limiter."

However, for same period Competition Touring and Competition Grand Touring Cars there is no mention...

Plus for "Non Homologated Cars" the technical regs state "An electronic rev limiter may be used for period F onwards.

If you want to fit one, in the real world common sense would appear to prevail.

Apart from possible reliabilty issues, as Simon says, a rev limiter doesnt help if you select 2nd gear rather than 4th.

[terence]

Thing is,that if you share the car regularly,and not overly sure on a drivers capability of observing the rev limit you instruct him to use,surely it makes sense?

[simon drabble]

a fair point but I would think the bigger risk is a bad downchange and rev limiter is not going to protect you from that! In a two driver race I would hope both drivers would be sufficiently sympathetic to not red line the car - however...

[Dave Brand]

Originally Posted by Mike Bell

It used the increase in centrifugal force as revs increased to break the HT connection, IIRC!

That's the way it worked. Apparently, 1960s manufacturing technology being the way it was, there could 200-300 rev/min variation in cut-off revs between units.

[GORDON STREETER]

I've got one of those rev limiter rotor arms amongst my collection of "clutter" on an old TC distributor.
I seem to remember they were a std fitment on new road going Mk 1 twink Cortinas, but most were soon replaced as they caused missfiring problems.

[FastDB2s]

BMs had them aswell, best ones produced by Bosch.

[rbm]

somewhere in the back of the workshop (or down in the cellar) I have a box of new ex-military rev limiting arms, they are beautifully made 24v high speed engine thingys and in period cost an arm and a leg (something around 50 quid each in the early 80s from what I remember)

absolute rubbish though - caused more misfires than you could poke a pig at.

[GORDON STREETER]

Originally Posted by rbm

in period cost an arm and a leg (something around 50 quid each in the early 80s from what I remember)

Sounds about right for loads of things that the government wastes our millions on, a mate of mine made some special parts for a vehicle that was going to be used in the Gulf war that cost serious money but was shelved at the last minute.
He was paid a lot of money but the parts were never collected and were eventually written off and scrapped !