Engine braking - a no no?

[nickd01]

Browsing a few threads here, and the opinion appears that in a TVR engine braking isn't a good idea.

Thing is, I'm not sure why.

Is it to do with upsetting the balance of the car? Therefore, I'd assume in the dry & straight it's acceptible to do it? Or is it something else?

I've not had the Chim for long, and I'm off for some driver training days once I'm a little more settled behind the wheel but a few tips for safer-driving in a Tiv are always appreciated.

Nick

[chassis 33]

Both these points only really apply to spirited driving.

Using engine braking down through the gears is a bugger if you don't get the heal and toe right, cos you'll lock the back wheels when the clutch engages and all hell will break loose, well not quite but you get the picture (remember Hakkinen at Monza (or was it Imola) a few years back crying cos he'd locked the back end up and spun into retirement)

Also if you're not careful you can over rev the engine on the down shift by changing gear too early.

Regards
Iain

[IM]

I've had my exhaust 'modified' and you have to engine-brake somewhat before then dabbing the throttle in order to release the 'pops & bangs'.

Hope I'm not condemning my engine to a slow & lingering death at the same time.

[theaxe]

I think the problem with engine braking is that if you're travelling at say 50 mph, you drop down a gear so the wheels want to do 40 mph they instantly break traction.

In a lesser car the momentum of the car is enough to raise the RPM of the engine to compensate, however a TVR engine is sufficiently powerful that traction of the rear wheels is the weak point.

Now I've confused myself...

[GreenV8S]

Engine braking a rwd car (i.e. closing the throttle so the engine is slowing the car down) is like pulling the handbrake on gently. In a straight line on a grippy road it's no problem. In slippery conditions or if you are cornering hard with no 'spare' grip it can be enough to break traction on the rear wheels and put you off backwards.

Clutch braking (engaging the clutch with the engine revs too low for the road speed) is like pulling the handbrake on hard. You might still get away with it if you feed the clutch in gradually and there's ample grip available, but it can easily go wrong.

The danger of both of these habits imo is that they are most damaging in the situations where you are most likely to do them poorly. They can both be OK, but you would be advised not to get into the habit of doing either of them.

[nickd01]

So, the "general" rule for a RWD drive car is that you reduce your speed with the brake before changing down gear to prevent the potential of traction being broken.

I assume a gentle "lift-off" of the accelerator - for example to just reduce a bit of speed on the m/ways is acceptable if it's done gently?

Maybe it's time to up-grade the brakes....!

[M@H]

I accidentally clutch braked into the "bus stop" at Llandow.. basically messed up matching the revs on changing down to seconds gear. Queue rear wheels locking and me getting into the first corner slightly sideways in a skid... (got through ok though ) apparently it looked good from the sidelines, I was pooooooing myself at the time of couse

I had some space around me then though to sort things out, simply no room for that to happen on the public road (ususally).

Edited by M@H on Friday 7th July 16:20

[jsr]

I only ever use engine braking when i know i'm staying in gear, ie between speed bumps or in slow traffic.

With more spirited driving, it's best to use the brakes (though i always heel and toe also)

I was always told engine braking only applied to old cars when brakes were not very powerful. Today's braking systems are much more powerful so we dnot need the engine to help us stop.

[IM]

GreenV8S said:

Engine braking a rwd car (i.e. closing the throttle so the engine is slowing the car down) is like pulling the handbrake on gently. In a straight line on a grippy road it's no problem. In slippery conditions or if you are cornering hard with no 'spare' grip it can be enough to break traction on the rear wheels and put you off backwards.

Clutch braking (engaging the clutch with the engine revs too low for the road speed) is like pulling the handbrake on hard. You might still get away with it if you feed the clutch in gradually and there's ample grip available, but it can easily go wrong.

The danger of both of these habits imo is that they are most damaging in the situations where you are most likely to do them poorly. They can both be OK, but you would be advised not to get into the habit of doing either of them.

You clearly know your stuff

IM said:

I've had my exhaust 'modified' and you have to engine-brake somewhat before then dabbing the throttle in order to release the 'pops & bangs'.

Hope I'm not condemning my engine to a slow & lingering death at the same time.

Am I?

[RichardD]

nickd01 said:

Browsing a few threads here, and the opinion appears that in a TVR engine braking isn't a good idea.
...

Along with being RWD, TVR's have large engines for the weight of the vehicles. If you are in a heavy car with a little engine, the effect of the engine is relatively small, but in a TVR the engine has more of an effect.

Imagine having seperate brakes (like a bike). Engine braking (large, ie braking that should be done with the brakes rather than subtle easing off the throttle) in a front wheel drive car is like putting on a brake just at the front. In a rear wheel drive drive car the best analogy I can think of is using the handbrake!

[biggiles]

I've only ever used engine braking while driving off-road in Land Rovers - for off-road driving it is a very useful and important technique.

Never used it on the road though.

[tahiti450]

nickd01 said:

.......the opinion appears that in a TVR engine braking isn't a good idea.

Basically as Peter has said and if you are skilled at "heel and toe" (and "double declutch" ) then it shouldnt ever be a problem, but otherwise in a very light rwd car with a big engine its going to be a recipe for disaster.

Edited by tahiti450 on Friday 7th July 18:13

[Mad Mitch]

Never had a problem engine braking. Old school always taught to use your gears instead of your brakes where possible. Guess old habits die hard...... The more you drive your cars the more you know how they will react. You also have a good idea how high the revs will go when you drop third to second say for a sharper corner.The gear change should be over and done with well before the corner. Dip clutch, pull gear lever into neutral plane, blip throttle to desired revs and select gear, realeasing clutch swiftly.The revs should not take a sudden rise once clutch is home if done correctly.... I have found then that taking the Chim into the corner on a neutral throttle ( Maintaining revs.) then gently applying as appex opens works very well and keeps the car well balanced. So lond as full throttle is not used untill traction can be maintained there are no problems... All the above can be done even on unfamiliar roads, you just have to react more swiftly.The key words in all situations and conditions are concentration, commitment, control and ballance.... Save the lunacy for track days and airfields guys...

[GreenV8S]

Taking a late apex, and accelerating gently through the corner rather than maintaining constant speed until you pass the apex, makes the car more stable and is also faster and safer.

[shpub]

Brake pads are also cheaper and easier to replace than the clutch.