ALEX307D

I'm thinking of getting a GEMS management system to use in my GpN rally car (forest rallys). I have just had a new core put in my TD05 turbo (basically a new turbo) and next was going to be a GEMS with anti lag,
however i have been told a few horror stories about melted pistons etc....

can anyone shed any light on the subject ?

Im planning on not going for any great amount of horsepower etc... just the anti lag function, and running on normal fuel, not that special racing fuel.

pro's and con's below please.

GC8

Did the compressor supplier have a buy-one-get-one-free offer on? Anti-lag kills turbos.....

stockcar

depends on how 'aggressive' you want it to be, a very mild form will have almost no detrimental effects but obviously won't have the pick-up that the full house system caters for.......................you pays yer money..........

alyn

911

Friend of mine ran a/l on a Gems on his hill climb car.

Never really worked well when 'tuned down' made lots of noise (was nearly excluded from events) and eventually went faster without it....
MOTEC seems much smoother?

Graham.

ALEX307D

Remember tho, it is a rally car, and isnt used daily.

I imagine i'll need a turbo rebuild every 6-8 events.Thats not what i'm bothered about, it's the rest of the engine, pistons etc... i dont want to ruin.

any one who has anti lag got any opinions ?

911

Alex:
Try contacting Zen Performance (Paul = Pavlo) I 'think' he runs al on his drag car.
Some of the big bhp guys on here do.

You could try Town End Garage too?

Graham.

ALEX307D

thank you P4LNY


Thats what i want, less lag out of corners,
and it only compete's about every month or so, so turbo life should last a full year, which i'd be happy with.

a melted piston would be a nightmare tho !

Town end garage (steve simpson) will be doing the GEMS,
when i have eventually put the 4 pots on, removed my servo bar, and replaced it with a solid one, and found enough Raceline wheels.

dazc

Steve mapped mine and I can't praise him enough. Gems or indeed any ecu is only as good as whoever maps it, which in itself should give you a better spread of increased power.

You wont notice any difference under acceleration out of corners with the anti-lag switched on, but when you change up a gear the turbo will have no lag, no pause (hence the name), and you will immediately be on boost. Same when you back off for a bend then accelerate. Instant urge.
I would say it's impressive.

If it's mapped well your car should probably be more reliable not less!

Daz

Gems also has an automatic cut out function for the anti-lag for when the temps start creeping above normal so no damage can occur.

Not convinced by P4NLY's experiences of anti-lag. Misses the point somewhat, it is in changing gear it's most effective!

dazc

Thats just naive. It's all about mapping mate.
Daz

ALEX307D

thank you daz, youve totally eased my mind.

top man.

it also sounds mint popping and banging ! haha.

dazc

Daz

Technik wrx

Be careful using anti-lag for the first time, you'll find that you have a harder brake pedal and you need to use more force to slow down. This is because the standard car uses vacuum assistance for the brakes and when anti-lag is engaged, you are not making as much vacuum (if any) therefore a reduction in assistance.

ALEX307D

technik wrx,


I'm putting the 4 pots on, and a solid servo bar (hence NO assistance from servo) as apparently, thats the right way to run them.
then you can keep the boost up around 0.2 - 0.3 then it has less to spool up to full boost, hence no lag "anti -lag"

Like you say tho, i need to be a bit weary at first with no servo, then again the old mk2 i had ran with no servo and i had no problems with that.

Technik wrx

It's amazing though, you don't know what you had till you lose it. Amazing how much assistance vacuum really gave the brakes.

In regard to health of your engine with anti-lag, all comes down to tuner as well. You should have a separate map for when anti-lag is engaged and also have rotational idle to help cool the engine more rapidly. Most of the anti-lag systems I have encountered didn't acutally make boost at idle though, it made 0 or close to 0 vacuum and thus made boost really quickly when you got back onto the throttle!

ALEX307D

i take it thats why most group N cars sound funny (rev up and down) at idel, which is really odd. hahaha.


sounds like just what im after, and apparently everyone raves on about this steve simpson (seems top guy judging off his e-mails)

P4LNY

Hence "IMO" daz, and as for backing off into a bend then accellerating out of it wasn't that what id already said all be it in different terms

dazc

....overtaking when your to lazy to drop down a gear IMO

Er..not really.
Daz

ALEX307D

dazc

thank you very much for your personal message. Most helpful.

top man !!

P4LNY

Clearly your ignorance stoped you from reading what was in front of your quoted sentence......"for coming out of corners"

Whatever....

Tim-H

I would maybe suggest looking at the newer possably roller bearing / twin spool ? smaller lighter turbos, I presume you are running a restrictor ? 32mm ? as you cant have a lot of air, some are upping compression ratios ( not sure on the regs for gp n, wrc is around 11/1 :-) mapping for lot`s of boost in mid range and as the turbo / restrictor runs out of puff higher up the rev range, not being to bothered, also the modern turbo spin`s up so much quicker you may not need or not as harsh antilag,
Have a good one,
Tim
ps there also seems to be a fair few about quite cheep as people seem to change them for "big power" you can`t have big power so they are ideal for you,
I run an unrestricted 18g/gt35 roller bearing hybryd on mine, I have never bother to set the antilag up, no need to,

Pavlo

I don't use ALS on my car yet, for drag racing it's simply not necessary as I never lift the throttle. ALS is there to keep the turbo spooled up in low throttle situations, say when you enter a corner, when you re-apply the throttle, BANG you have response.

The WRC cars use a well evolved system that allows you to have some vacuum (used to activate the ALS valve) and cooler exhaust running. However most ECU's only allow for the normal system whereby you ignite late in cycle with the exhaust valves open. This can overheat just about everything from the valves to the turbo. SO it needs to be setup with care. Ideally you still have a slight vacuum in the manifold with the ALS working, (bordering on atmospheric pressure) and the high pressure will be present on the other side of the throttle plate. When opening the throttle you have instant 0.5 to about 1 bar boost, which mean more boost very quickly after that.

However to make that boost, the ignition timing means no power, so the ALS is designed to be working when you don't need power, ie coasting into a corner, or maintaining speed, it can't work when you want full power.

Paul

Tim-H

A breif explanation of MY understanding of anti lag , please feel free to suggest on any errors (excuding spelling :-)
When backing off for a corner or the like, you lift throttle, air bypass valve opens (depending on it`s size it is a govening factor in "harshness / effctiveness, )injectors squirt a smallamount of fuel in, but instead of "firing it @ whatever before TDC to produce engine power, it is ignited after for the force of ignited gasses to exit out the now open exhaust valve`s, spinning the turbo whilst "off the throttle,"
problem is, it aint supposed to be burning where it is, and although it if setup very well and used properly, it may not melt anything quickly, it won`t do it a lot of good, thermal stress is another issue, very short sharp temp changes in gas`s

I would not think the "rough tickover" you mention is antilag, some more likley , when they were mapped on a dyno / rollers tickover / cold running is not an issue, the car was probably hot when they started, the car rairly run`s in that range and as long as it will start that`s near enough, light flywheels don`t help, also i beleve motec are not very good at idle ?
Have a good one
Tim

Pavlo

Tim,

That's all pretty correct. What the rough idle sometimes is, is a fuel cut idle speed control, to control the idle despite a jacked open throttle. If you have a solenoid air bypass valve, then the rough idle isn't necessary. Although you can also use it to cool down the engine and exhaust by cycling lots of air through it.

Paul

Tim-H

looked for a method of useing a little solonoid on the throttle stop on a gp A car , a while back, to give more "idle opening" when using antilag, he uses a bypass +a fairly large closed gap iirc 1.5 mm, but it won`t give enough airflow, not sure if he got it working or not,
Have a good one
Tim

Adam M

excuse me for butting in, but how is the safety all about mapping?

regardless fo what your engine is doing, if you want antilag you need the fuel to be delivered unburnt onto the hot blades of the compressor.

At this point the fuel burns and the resultant gases push the turbine round.

This can be done via a few routes, but the route that causes fuel to be burned inside the turbos generates massive heat there and the tiny explosions whch cause the turbo to generate useful boost have been likened the effect of hitting your exhaust wheel with a hammers continuously.

I don't see how mapping is going to fundamentally change this.

You can map it less aggresively, but then you get no boost, just lots of noise. antilag of this type kills turbos, that is a fact, the question is how much antilag do you want and how happy are you to treat turbos as consumables.

If it was as avoidable as having steve simpson map your car properly, then why do group a and wrc cars change turbos so frequently?

ALEX307D

I would of thought the WRC and Gp A boys change turbos more frequently as their cars will be mapped very harshly and for out and out power, e.g never dropping below 1 bar,
whereas if mapped with turbo life taken into consideration (e.g GpN and Clubmen boy's) then it's not as bad. E.g rebuild every 6-8 events.

If it is so bad, why does 98% of GpN cars run anti lag ?

Pavlo

Do you mean the 98% of clubman racers doing it out of their own pockets, or 98% of the PWRC group N competitors who will have budgets approaching £1million?

The harder you are on the car, the less the ALS will be doing. WRC cars will have a number of turbos PER EVENT!

Why exactly do you think you need ALS? For the cost and trouble of going to an ALS capable ECU, you should consider getting a 2.5 conversion which will have better torque and zero lag on something like a td05, which will see you to 340hp.

Paul

ALEX307D

YES THE 98% DOING IT OUT OF THEIR OWN POCKETS like myself.

obviously if I went for a 2.5 conversion I would get more power, but that defies the object of being in Gp N (Showroom category) and then puts you in a bigger class.

I already have a TD05, and isn't it blatantly obvious that the harder you are on a car the less the ALS will do.

Drag racing obviously is just about out and out speed, no real driving skill involved. so hence you need maximum power. Rallying isn't drag racing

911

Not sure if i agree with drag racing being a sport lacking driving skill (bravery?)
Having been to Santa Pod recently and seeing well over 300mph in 4.8 secs there is a lot of skill there, both in the car and the driver.
OK though, a Run what You Brung meeting isn't quite so skillfull, but squeezing the last tenth/hundreth out is very hard.

I hill climb my Impreza, is that 1/2 way between Drag and Rally?

All the ALS's Ive seen in hill climbing have lead to little gain, some going faster without it.
Launch control is something different though.

Graham.

carlos_hiraoka

Adam, antilag/boost response/boost enhancement has a lot to do with mapping, in fact there a few parameters like: maximum time allowed on overrun boost, EGT compensation, 2d tables for both retard and fuel cut, etc. In fact Group N cars properly mapped do not "treat turbos as consumables" they can last as long as 4 events with ALS fully used on each stage. And BTW on Group N cars it is mapped so that when it is activated the engine makes 0 psi (no vacuum) and normally it isn't mapped too aggressive cause that would cause and ON/OFF type of response, and give no throttle control.