Originally Posted by Stori
I would certainly be considering how I was going to use the car. Unless you use a low pressure turbo then you will experience lag which is unpleasant in city driving
I have a preference for Supercharging, but it is a really a personal thing so-to-speak
Turbo Lag is determined by the size of the turbo and the exhaust side fan blades/turbine,and not the amount of boost pressure that you run.
You can and will still get lag on a low compression turbo conversion if the size of the turbo does not suit the engine itself.
A Garrett T 25 sized turbo is ideal for a turbo conversion on a standard 1.6 litre twinspark.Its smallish in size has small compressor and exhaust turbines/fan blades,and this means the the turbo spools up faster therefore reducing lag to a minimum.It will boost away with no real lag at 6-8 psi boost but is also cabable of about 250-260bhp at 1 bar boost.
You can still get lag on a turbo,regardless of whether you run low boost(6-8 psi) or highish boost(12-23 psi boost).Every turbo(regardless of size or spec) will give some lag,some give more than others.
The only proper way to completely eliminate all lag is to use an Anti Lag System on the car.
This system cuts the ignition spark to the engine and directs fuel vapour onto the hot blades of the turbo,this results in the turbos fan igniting the fuel vapour and the resulting combustion keeps the turbo blades spinning/spooling and this eliminates all lag,as the turbo is already spooling/spinning away as you launch/accelerate.
This system also spits flames out of the exhaust from the fuel vapour igniting from the hot turbo and this gives a loud whistling and popping noise form the turbo and exhaust .
That is what anti-lag is and does to a turbo and car.You can get an anti-lag system as part of a stand alone/aftermarket engine management systems.Once you drop the clutch and accelerate the ignition spark re-engages and ignites the fuel vapour in the engine instantly for maximum power/acceleration.
The other option to eliminate lag is to fit a Launch Control System(Race Logics system is one of the best systems on the market) in the car.This is a system that keeps the cars revs at around 4-6000 revs as you sit ready to accelerate in 1st gear,as you accelerate the cars revs are so high up that the turbo doesnt bog down,as its already spooling away due to the high revs of the car.
Launch Control usually comes/is incorporated with Traction Control systems that some WRC and Group N rally cars have installed in them.
The launch control causes the car to accelerate at full revs,while it combined with the traction control system keeps the cars wheels from spinning up from high revs and sudden power from the engine.Therefore you get a very fast/smooth launch,but with no lag and no wheel spin either.
I have both the Anti-Lag system(fitted with to the Omex 700 engine mamagement) and Race Logic Traction and Launch control systems fitted to my car.These are very expensive systems to have installed and set up on any car.Hope this explains about lag and anti-lag,as some people have asked me before what anti-lag is and how it works