S1 Anti lag System

[Billman]

I was seeing some pictures of an S1 Anti Lag system witch is build from an Wastegate valve and some runners going to the exhaust manifold!

So my question is: How would something like this behave on a street but tuned S2 ?
Maybe there must not be separate runners for each cylinder but one straight to the collector!

I think:

1. It would cool down the turbine housing and wheel since the compressed air is much colder that the exhaust gases

2. Why din't they used an ordinary pop off valve to blow the air in turbo intake like the production cars?

It looks like this

[audiman]

Got any other pictures of it? Where is it getting its air from??

[Billman]

Dont have other, but every S1 engine picture should do! There was another picture in the forum somewhere!

I gets the hot air fron the turbo pressure side!

It is a kind of an ancient Anti lag Sytem! Todays Rally cars retard the timing, so unburned fuel goes to the exhaust manifold and burn in there! The explosion keeps the turbine turning but it i salot of stress for the turbo and the head with all that temperature!

[RSCoupe]

James Bufkin has this on his UR Rally car, although not connected at present. There are pictures on Motorgeek.

[CR500Dom]

Als

ALS is designed to keep the turbo spinning on a closed throttle, they started out pretty crude but are getting increasingly complex.
Basically you take HP air from the compessor outlet and pump it in to the exhaust or head (You can use the secondary air injection ports on a lot of Heads, used for faster CAT lightoff times) as close as you can get it.
When the throttle closes and the DV opens, instead of diverting back to compressor inlet, it diverts to exhaust "Ports".
This helps to lightoff unburnt fuel in the exhaust, spinning up the turbo.

This is normally a comprimise, running wide overlap cams, firing injectors just before exhaust closes etc to get the fuel in there in the first place.

There are much better ways of doing it with more control.

Now there are "Indirect injectors" into the air injection airstream, which gets fuel in the right quantities, nicely mixed into the fresh air charge these are controlled direct from the ecu, in effect what you are trying to achieve is a secondary combustion chamber withing the manifold.

This puts huge stress on the manifold as well as a lot of heat in to it.
The WRC cars run Inconel or Nimonic steel manifolds, to withstand the temperatures.

There are some other things being tried at the moment to move this on even further, if you want to do it, the ECU is very important and you have the benefit of no rules So you can go further than us :mischeif:

Think along the lines of Torque rather than HP, WRC Cars are 2litre single turbo, with an inlet restrictor to nominally limit them to 300hp
So they Rev to about 4500-5500 rpm and produce in excess of 700N/m torque with a very flat "Curve"
This is all available from about 1800 revs as well

HTH explain
Dom "Takes work hat off again now"

[sal_s2]

Do ecus such as motec and dta which have als built in require additional hardware/plumbing to operate?

[Billman]

not specific hardware but if you realy going to programm it as an anti lag system and not only as Bang Effect then yo usurely are going to need soon a new turbo because of the hat that is beiing produced!

I was thinking what it will be if only blow the air instead of the compressor to the turbine side !

[Chris5044]

how much would this cost to make............ i hate turbo lag!!! anything to get the beast boosting early would be nice

[Billman]

Yes but dont forget, the rally teams change the turbo after every race! this means ca. 400 - 600 km and then new turbo!

[NoNonsense]

how much would this cost to make............ i hate turbo lag!!! anything to get the beast boosting early would be nice

It would be WAY too harsh on your manifold and turbo...it's not meant for a street car by any means.

[WabTheKing]

mr plod wouldnt like it either as anti lag on public roads IIRC is illegal - not that that would stop me tho!!

i just dont fancy replacing my turbo every month

[Billman]

Thats why i asked only about this "old" type of anti lag with just compressed air! I think in terms of turbine wheel spin it will be more effective than a blow off releasing the air on the compressor side!

The problem is i am not able to tell what kind of drawbacks will a system like this have!
If it at all works only with compresed air!

[WabTheKing]

so are you saying that this works pretty much the same as a recirculating valve ( only not as we know one) instead of forcing unwanted air through the cold side of the turbo, it forces it through the hot side?

mmm, works in my mind anyway

[NoNonsense]

mr plod wouldnt like it either as anti lag on public roads IIRC is illegal - not that that would stop me tho!!

i just dont fancy replacing my turbo every month

Do you know what else is illegal!? Speeding above the limit is illegal too! And I'm sure you've done that at some point or another!

[WabTheKing]

I WISH!!! you try speeding in a car that rarely makes it out the garage!!!!!!