Choosing a Turbo...

That's one of the things I'm talking about above. If both units compressor map meets the requirements, the larger unit could introduce additional lag that is not desired so while, at first glance, the larger unit seems a better bet, the smaller unit may produce better results.

Conversley he may find that the larger unit has a freer flowing turbine, allowing a higher peak rpm where the smaller unit is beginning to impede the exhaust flow. Or indeed, maybe not. :D
 
Jonny ///M said:
So he can get loud bangs and flames out of the exhaust?
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Well, that is a side-effect of an anti-lag system, but the difference it makes is astonishing. zero lag, no waiting for the turbo to spool up. nothing. Just instant power availability.

TBH I'd agree 100% with Volospian above, namely to do the math. The best thing about owning a car that's so often modded is that in most cases someone will already have had the same options presented to them as you currently have, so you have a knowledge base to sift through.
Jonny ///M said:
What is it i have heard about antilag being bad for turbos? or is it BS?
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I've never heard that, but it is possible although i wouldn't think it'd shorten the turbo's life noticeably.
Simon or Dogbreath can probably shed some light on this.
 
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The_Dark_Side said:
Well, that is a side-effect of an anti-lag system, but the difference it makes is astonishing. zero lag, no waiting for the turbo to spool up. nothing. Just instant power availability.

TBH I'd agree 100% with Volospian above, namely to do the math. The best thing about owning a car that's soften modded is that in most cases someone will already have had the same options presented to them as you currently have, so you have a knowledge base to sift through.

I've never heard that, but it is possible although i wouldn't think it'd shorten the turbo's life noticeably.
Simon or Dogbreath can probably shed some light on this.
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Yeh i had a read up on ALSs the other day and found it quite interesting how they came up with it.

Still dont get how they adjust the cam to keep the exhaust valve open though? The ecu can retard the spark timing for it though.

I think it was to do with turbo bearing failure regarding anti lag. Dont know if that for turbos that arent designed to be used with an ALS though.
 
Jonny ///M said:
Ohhh so on older cars without variable valve timing etc the timing would have to be altered from the very start? That would mean the exhaust valves would still stay open at high revs aswell though.

So ALS for modern cars only?
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As i understand it the exhaust valve timing is unaltered. It's only the fuelling that changes.
 
Jonny ///M said:
Still dont get how they adjust the cam to keep the exhaust valve open though? The ecu can retard the spark timing for it though.
.
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http://www.rallycars.com/Cars/bangbang.html

Apparently the issues lie with the fact that the car is pretty much igniting excess fuel in the exhaust headers, causing a lot of heat and stress in the manifold and the unit itself.
 
Best ask this question where you'll get a more experienced reply, ask on the MLR as there's a lot of guys on there running big tubs, everything from an 16g upto GT42r. Karlosg is running a monster 3, as is nwwill, search out their posts for their experiences

A 35 should give you around 650ATF, good for drag racing as the revs required to spool it, full boost by 5000, rev it up2 9000! Its all the other bits, fuel system, injectors, intercooler, ecu, clutch,

A stroker is a good way to help spool, a 2.3 MAD engined 35 spools by about 4000!

Its horses for courses, i'm quite happy with my paltry 6 running [email protected] bar, max i'd like to run as a daily drive is about 420 that'd make for interesting driving.

If you're spending a lot of you're hard earned cash ask some1 who's been there, done that & got the lag!
 
Afaik, they just don't ignite the fuel until it is being pushed out of the combustion chamber via the exhaust valve, so the explosion and pressure happens in the manifold and turbo.
 
AFAIK anti-lag systems just retard the ignition timing significantly, no need to alter the cam timing. The point if the exercise is to have the mixture starting to combust when the exhaust valve is opening, the resulting mixture of burning fuel and exhaust gasses is pushed through the turbo keeping it spinning. It's very hard on exhaust valves, manifolds and turbos, certainly not something you would be using on a road car.
 
Simon said:
New turbo every 500miles would put me off. Plus no doubt several exhaust systems and manifolds. Plus burnt out exhaust valves and valve seats :)
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500 miles of continuous use.
Take Nitrous, a small bottle might only last you 10 miles...but if your car covers 10 thousand miles that happen to incorporate those 10 miles it doesn't look such a bad figure.
Again with anti-lag, the damage is done by all the extra heat for the most part. So, as i said above, if the system can be turned on/off when needed then your car may cover 20k miles before you've accumulated those 500 miles of anti-lag use.
 
The_Dark_Side said:
500 miles of continuous use.
Take Nitrous, a small bottle might only last you 10 miles...but if your car covers 10 thousand miles that happen to incorporate those 10 miles it doesn't look such a bad figure.
Again with anti-lag, the damage is done by all the extra heat for the most part. So, as i said above, if the system can be turned on/off when needed then your car may cover 20k miles before you've accumulated those 500 miles of anti-lag use.
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One use may be enough to blow the turbo, I made the 500miles up just to indicate how much shorter components lives become, it all depends on how severe it is but I can imagine it will be used quiet often, I would use it a lot if I had it :D
 
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