Scott J Davies

Pete

Its the same in the scoob as in any other car, drop it a cog or two to avoid lag and then nail it.

Or if in th ewrong gear try a bit of clutch feed.


Scott

Orville

Tie it to the tow bar of an EVO VI.

Only Joking .

Fosters

do evo vi's come fitted with a tow bar?

suits the evo's image I s'pose.

(edit: sorry forgot the smilie!)

[This message has been edited by Fosters (edited 20-07-2000).]

pslewis

You will have to find an EVO first - haven't they all been recalled???

Apparently they are now all getting the impreza engine and running gear

Pete

Yex

My car (MY98) will hesitate if I keep the revs even in 2nd gear and then try a rapid acceleration. From other threads the ECU prevents full power/torque going through the drive train due to potential damaging effects.

If I need to overtake in 2nd gear I try and keep well back from the object car(s) and accelerate towards them smoothly so I can complete the pass at max boost or back off if traffic appears. The method described by Scott also works as the car responds well to downchanging and asking for max boost at the same time...I haven't quite mastered this yet and get earache from the wife when the car jolts on downchanging, and then proceeds to press her into her seat whilst on boost

Yex

PeteC

This may sound like a dumb question, but how do you obtain the best acceleration from a Scoob? I'm not talking here about throwing mods at the car, or about the "traffic lights Grand Prix", rather, what's the best technique for accelerating/overtaking quickly?

I've read posts on here which suggest that if you hold the car in, say, 2nd for a while in readiness for overtaking, and then floor it, you don't get the best results. Can you enlighten me, please?

Pete

MorayMackenzie

Use the torque, luke!

Two extreme techniques to aid overtakes that you don't really want to try are:

A) Left foot braking to hold speed as you press the loud pedal and build boost for the overtake. Not good for the car, especially the brakes.

B) Engage anti-lag system. Not good for other driver's state of mind.

IWatkins

Moray,

Might not be good for the other drivers state of mind. Do you notice that they go backwards quicker than they should when you overtake with ALS on ? "Sh*t dear, he's shooting at us".

Left foot method works very well but can cause brakes to get very hot, something that you might not want if you have to abort your overtaking move

Generally speaking, I find as long as I can hold the car at about 3k rpm as I "hover", flooring the throttle will give almost instant boost. Nothing worse than pulling out to realise you still got to wait a few seconds for boost because you were in too high a gear.

Other method of course is to wait for the dual-carrigeway or if you are really hard (and have big brakes) is the overtake into a braking area trick. (I'm joking about that last one)

Cheers

Ian

Yex

Scuse my ignorance but what is the "anti lag system" and how do you switch it on and off?

Yex - either got a toy on his MY98 that he doesn't know about or doesn't realise when someone is taking the p1ss out of him

Hos

iTrader: (1)

lol... glad you asked that question first! Was beginning to think i was the only one that didn't know

rsquire

Wear heavier shoes

Richard

chuckster

Yex, ALS is a toy(genuinely useful extra functionality? ) made available to Moray through changing to the MOTEC ECU. You don't get it as standard on any Scoob save the WRC P2000. It is a system whereby the turbo is kept spinning even when you are not revving the engine, and returns maybe 5 MPG when engaged? This way you are never off boost.
(Excuse innacuracies plse Moray )
Cheers
Chuck

Yex

Oh, right....I'll go back to mowing the lawn

Yex

Paul Frank

ALS on a road car?

Hmm
OK time for another lecture from the board expert on ALS the esteemed Mr Felstead, this will include many comments on problems / downside . . . listen & be educated chaps.

Paul

zoog

doesn t antilag fry the exhaust valves on a road car?

johnfelstead

Below is an explanation of how a proper late 90's Group A Rally Car Anti Lag System works.

The mild road car versions discussed above i do not class as ALS systems in the true sense of the word as full spec ALS systems are very violent in there application and produce instantaneous throttle response.

You would probably fry the local feline comunity if you went around town with your proper group A ALS system switched on.

This is how the rally systems work.

Firstly, boost is controlled very acurately by using 2 fuel injectors as air valves, these feed the boost/atmospheric pressure to the waiste gate actuator, allowing minute and very fast acting boost control.
Secondly, the normal method of controlling engine iddle via an idle control valve, that bypasses the throtle butterfly is dispensed with, the static idle is set in the old fashioned way by a locked off bypass screw.
Thirdly, where the iddle control valve used to be, a new valve is fitted that has a solenoid controlled valve (looks like an engine inlet valve internally) that can open/close the throttle buterfly bypass orifice very qickly.
Forthly, a miram turbo shaft is used to withstand the massive increase in turbo temperature generated by ALS.
Fifth, there is no dump valve used on an ALS equipped engine, the whole point of ALS is to keep boosting the engine, even on closed throttle.
The way it works is that when you come off the throttle, for example braking hard into a corner, the throttle butterfly closes as per normal, once the boost drops to a certain level, the ECU starts to pulse the Throttle butterfly bypass valve, this has the same effect as you constantly stabbing the throttle on and off very quickly, this means that the engine is being driven by the ECU as though it wants to accelerate again, however this occilation of the throttle bypass valve is happening so fast, it has the effect of allowing the turbo to stay spinning yet produces no additional torque to drive the car forward.
The effect of all this is that massive heat is generated in the turbo exhaust side, which ignites all the excess fuel, there is no deliberate overfuelling going on to explode the turbo impellar area.
The most modern of ALS systems on the current world rally cars are far more efficient than a couple of years ago, which is why the ALS banging was less aparent this year on the RAC rally.
The turbo used in ALS equipped rally cars is smaller than you would see on a race car for two reasons. the first is that the FIA has a mandatory 34mm turbo inlet restrictor that limits air flow into the turbo, this means that it is pointless useing a large inlet turbine unit as the inlet could not flow any more air, secondly the lag would increase due to the inertia of the larger impeller.

We use water Injection to allow boost to be maintained, especially on a very hot day, the intercooler size is limited by the FIA rules so charge temp control is a major issue on rally cars. Also keeping the Intercooler relatively small also helps reduce inherant lag.

The water injection system works by injecting a fine mist of water/air into the inlet plenum chamber when the boost/air charge temp reaches 42 degrees c, and is higher than 6psi. Below 40 degrees C it has been found that WI actually reduces power so it is important to have a fully mapped WI system.

This is not the same thing as intercooler sprays, these cool the external surfaces of the intercooler to help the cooling efficiency of the air/air intercooler.


Happy paul?

D Noble

mr felstead,
am i right in thinking then that if you brake or lift off, the turbo keeps spinning but produces no power to drag you off into the first ditch? if so when power comes on,it must be a hell of a bang,how do the gearboxes/drivetrain/drivers underpants/cope?

regards
Dave

johnfelstead

yes dave, it produces no discernable power whilst you are off the throttle. Although there is plenty of air getting into the engine the fuelling is very light.

We have had a couple of times in the past before we had our service routines fully sorted where the air valve had stuck open rather than pulsing, gets very interesting braking from 120MPH on the loose into a hairpin when that happens.

We now clean the air valve every service (approx 20 miles) as it gets a little sooted up with blow back, we have to relocate the air charge temp sensor from the plenum to the other side of the throttle buterfly as one of the side effects of the ALS is to melt the sensor if left in the standard location, forgot about that. LOL

It still helps to left foot brake in a 4x4 forest rally car but is not as essential as without ALS.

The power delivery charicteristics are very nice, just like a N/A engine. We use very large diffs, 7.5 inch front and 9" rear and a 50/50 torque split to cope with the huge torque (480lb/ft) we see with these high compresion ALS equiped rally cars.