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Engine detuning

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crasheur

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Another daft post, I'm afraid.

I have an R4 GTL which I'd like to use for driving up muddy hills.

Ideally, I'd like to be able to place the car in first, release the clutch and climb a one in three (with two big blokes in the car) hill at tickover.

If any of you have any advice how this might be achieveable (or any other thoughts on the subject), I'd be very grateful.
 
I'd be very suprised if you could get enough air past a virtually closed throttle butterfly to provide enough torque to to what your asking.

Im not convinced even the 1108 has enough at wide open throttle to pull two big boys up a 1:3....

and if you have got enough torque, if your hill is muddly like you say, traction is your next headache.
 
Hi, are you looking at doing trials then?

I posed the question a while back search for 'trials' (I don't know how to insert a link). Have not done any (well not in the R4) but think they could be fun.

Sunburn Red though sounds really quick though, I think ones in that colour possibly go the fastest of all. Could be loads of detuning. :p
 
Trials it is.

I've taken everything I know about trials and come to the conclusion that a Renault 4 would be the best thing in the world to use. At least FWD and production.

In reality, it's only the most recent of a series of best things in the world (Tigger syndrome). Each earlier guess turned out to be quite poor.

From what I've seen, apart from everyone else being better than me, a lightweight car is part of the formula.

A Kitten, whilst fun, would put me in a class that doesn't get very many runners, so I looked for something FWD and light. Hence me boring you here.

I've hoping a light car wont need as much grip to pull itself up (but then it could just float on the thousand years worth of compacted sheep sheet that seems to be a ubiquitous feature at these things).

They did well in the Dakar....

Anyway, apart from doing horrible things to the camshaft with a dremel, I'm a bit stuck. For low RPM torque on trials bikes, I understand bikers replace multivalve heads with twin valve heads and put smaller carbs on. With a Quattrelle? Who knows? I've seen a bigger carb on a Honda C90 and whilst I haven't whipped the rocker cover off, I'm guessing I have the minimum number of valves required to make the engine run.

Not that the engine has run, yet......
 
The stock GTL engine is an already detuned engine of the 1108cc R5 engine. With 34HP at 4000 rpm, imagine its torque curve...I doubt you need more...
You can fit a F6 gearbox that had a 4,125:1 final drive (instead of 3,67:1 on GTLs). Or if you want even more torque, fit the 45HP 1289 engine (discussed somewhere else here).
 
More of a torque blip around 1100 rpm I would have though - and then it runs out of air.

I originally thought they put that asthmatic little carb on their for build cost reasons - turns out it was to take advantage of the French tax system.

I like the van box idea. That's an excellent spot, by the way. It should improve the 0 to 36.23mph time too - assuming I get good at the Musketteer gear change.

Well, if anyone has a spare box for a van and would like to exchange it for some pounds, please let me know!
 
What trials you looking to do? MCC stuff?

I used to go on one near South Woodham Ferries, in an Austin 7 Ulster think it was Chelmsford Motor Club who organised it, not sure it still goes on?
 
If I haven't lived up to my name by February, the Exeter trial would be good.

In the meantime, I'm embarrassing myself in the MSA national production car trials.

It's been a steep learning curve going from some local fields with some fair drivers to far away lands (Wales) with the best drivers and the best developed cars.

Being such a small sport, there isn't a book on development. All development theories are mixed in with healthy portions of heresay, misdirection, leg pulling and good humour. Do I really want to fill the drive wheels up with water?

If the Quattrelle does slightly better than the Panzerwagen I took to the last event (and get's us to the start gates), I'll be a proper convert.

Strange...... For some unknown reason, I've got a desire to drive up the hill with a chicken jumping around the boot.
 
The R4 isn't perfect for traction up hill you know. Weight transfers to the rear, and the inside front wheel lifts spinning away all the power. Not like one of those VW Beetles or any rear wheel drive car.

Wonder if you can get a locking differential - that would help a lot.
 
if all your concerened about is traction on the loose stuff and to hell with the general driveability you could always weld the diff up...

Would be a pig on the road though.
 
We've actually got a rear wheel drive car for trials. A Marlin.

There are some issues though. First, as it turns out, we bought the wrong one. It's a Vitesse based car - as opposed to the Marina version. The non rotoflex transverse leaf spring swings the rear wheels about like a pendulum seeking the area of least resistance and grip. Secondly, it doesn't work. It's on it's fifth owner and it's never been finished. Thirdly, it'll never pass and SVA.

The other thing regards the lack of people that turn up in RWDs. This means you might win, but not get any points.

Welding the diff would be good, but, err, unethical. You're not even allowed winter tyres!

I have seen some FWD cars (in the hands of experienced drivers) do some unbelieveable things. I suppose it's all part of the challenge.

It's a fairly unique type of challenge. I suppose that's why information is so thin on the ground.
 
I had a Vitesse mk1 and trying to find grip on a normal wet road was bad enough(lots of fun though)

I'd try to lower your gear ratios as much as possible via the final drive.This would also give you a close(r) ratio gearbox and how about smaller wheels/tyres? This to would lower the ratio aswell.
 
Tough one that.

The final drive idea is probably a goer.

As for wheels, I'm not sure.

Do you want skinny wheels to cut through the mud, or fat wheels for contact area. Tall tyres will have more give in the sidewalls at 14psi and squelch out, smaller tyres will give you better ratios.

For every pro, there's a con.
 
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