cams with antilag
Turbo Mini Forums

Hi all,

Looking at sorting my cam profiles for my 970 turbo k-head racer. I've got an idea of what I'm going to run but would be interesting to hear what people think.

What's the theory behind using low duration cam profiles with turbo. I'm guessing its to spool the turbo up quicker. But if I'm running anti-lag then surly I can run a wilder cam?

What you rekon?

Chris

I think your alreaddy at a benefit by being able to widen the LSA of the camshafts in relation to each other.

Even 280 degree rotation shouldent cause an issue in a competition car.

I mean, look at the don, thats running 280 degree cam profiles as far as im aware, i may be totally wrong.

But look at how quickly it builds boost on the line.

http://www.youtube.com/watch?v=Xlmh-OZOUVE

cams and turbo's is a tricky subject,

normally short duration cams with little overlap are used, as there is higher pressure in the exhaust manifold than in the inlet so you will tend to get reversion, going to a longer cam makes this situation worse killing low speed power and not really gaining any thing at the top end.

The trick (apparently) is to use a bigger turbine so the exhaust manifold pressure comes down giving a smaller ratio between inlet and outlet pressures.

Trouble is its all a massive balancing act, different combinations will be needed to be tried and eliminated to get somthing that works wall

I have read that the avonbar phase 2 cam is the one to have but this is not from experiance, just what ive read on TM

Confessed addiction to everything mini

It's simple. Mild cams work everywhere.

Big cams are like shit down low, for little improvement up top.

And anti-lag has nothing to do with cam profiles.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

It makes sense that you should be able to, but there can't be that much to gain? you could have to look at some of the jap cars or something to get some more info as they have it all tried and tested. maybe carl or tom will be willing to give you some info on the dons setup.

Joe if he is using anti lag surely he can use a bigger turbine therefore a longer cam?
In this instance you wouldn't use a lot of the bottom end thanks to the anti lag and the gain at top end is an advantage in a competition car (or have I taken racer to literal?)

Anti-lag itself is an interesting subject - what type do you intend to run ???

Schrödinger's cat - so which one am I ???

Has anyone run anti-lag on a mini before?

Confessed addiction to everything mini

I would be surprised if any club event would allow anti lag as the anti lag would surely not meet the noise limits.

I was involved with setting up anti lag on a Drift Works car, the anti lag more for show. It never got used in an event as it was too damn loud. softening up the settings did not give the anti lag results that the huge turbo needed.

Check it out

http://www.youtube.com/watch?v=UnD-LqFbDzY

Edited by Carl S on 28th Nov, 2010.

if thats what your after, use the swift tune SW5

I'm running a twincam head so normal mini cams dont matter.

As someone said if using anti-lag the turbo is going to be bigger hence wanting to run longer duration cams. I already have the plans for the cam profile I just thought a discussion about the subject would be good. And might make me tweek them slightly.

As i'm running full fuel injection and timing, along with an ecu which supports anti-lag, its shldnt be that hard.

The ECU retards the timing and adds fuel when you lift off. It also open an idle speed type valve to allow air into the engine while the throttle is closed to allow combustion.

Only downfall is you have no engine braking!

Antilag is used during MSA rallys... hillclimbs/sprints are also governed by MSA regs so anti-lag is fine.

The noise test states 110db at 3/4 rpm. At 3/4 rpm anti-lag wont be active.

Chris

I would be tempted to run the standard cams set at a higher LSA.

The popular choice of cam for the 1293 5 port high boost turbo is the Phase 2 which has 264/290 degrees duration ground on a 110 degree LSA which is far from "mild".

The only cam that I'm aware of that is known to give a bit more power than the Phase 2 has slightly longer exhaust duration and LSA.

If you want to modify the K cams, then probably cut the inlet duration down a bit.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Sounds like an interesting project, anti-lag systems are regularly used in rallying and the WRC and has great advantages as it allows you to use a larger turbo due to no spooling :) yummy but not easy to get right!

Confessed addiction to everything mini

Luckily I can have all the dyno time I want :) to get it right!

I would have thought that any event that imposes a noise limit, the organisers would be very interested in a car that is overly loud after it had passed the noise check.

Edited by Sprocket on 28th Nov, 2010.

Yes you're right.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

At some events the noise testing is done as a drive by, but this is normally at a full throttle point of the course so there will be no anti lag.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

How do rally get away with it? Are we sure anti-lag is that loud?

Only loud when there is no load demand ie gearchanges and standing startes etc none of which when the noise tests are commonly thaken place

Confessed addiction to everything mini

The noise test as we all know is floored for a number of reasons. I and many otheres get different readings at every event. Anti-lag would not form part of the test, but organisers might have a quiet word if it was particually offensive.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Is the application of anti-lag going to impose high shock loadings on the drivetrain?

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Might contact MSA to confirm anti-lag noise regs.

Why would it shock the drivetrain? When I go back on power it will be there in one big hit? Guess I will have to apply power nicely :)

Chris

If something is worth doing, it's worth doing half of.