Hi guys

To what extent do you find that ambient temperature affects the performance of your turbo cars? I know that higher temp = less power and the reasons therefor, but how much do you find it actually affects your car?

Hi,

I live in Pretoria, and yes, I can definitely feel a difference on my 2001 A3 1.8T. I think the difference is probably +- 10% or so ? Not sure what the % could be ... but on a cold morning my car goes like it should, being standard and all, that's not too great haha. On a day like today (30 degrees plus), I can feel it's very sluggish to perform.

One way of sorting this problem out is by adding another intercooler like the S3's have 2, but then you get a little bit more turbo lag, don't you ?

Jan

The solution is easy (if FWP was not an issue) and that is to fit Water Injection. It solves all three the major problems we have up here in Gauteng, 93 octane, high ambient temps and lack of oxygen. It does not have the downside of more lag you get when you fit a bigger intercooler.

Before I fitted the Aquamist 1s system (about R3000) my intake temp on my S2 would rise from 18 degrees to 37 degrees by just nailing it in first, second and third! With the WI the intake temp rises 3 to 5 degrees when I do the same.

The downside to WI is that you blow your engine on an car that is chipped for WI when the water stops! Simple solution to that is not to chip for WI! I know 20VT is very hesitant to chip for WI. If the car was not chipped for WI, the water stopping would be like filling up with 93 on a hot day after you were using 98 - not dangerous at all.

From an earlier post I put on the Audisport forum from an article James gave me. Good indicator of heat vs. power loss;

Heat soak plays a bigger role for us, so the following data will appeal to those who are intercooling, water injecting, or trying to emulate Stu "The Airduct Man" Thomson

Intake Temp Power Loss Example

20c 0% 200bhp
40c 3.5% 193bhp
60c 7.0% 186bhp
80c 10% 180bhp
100c 13% 174bhp


Food for thought,especially in good old hot SA!
Incidentally, we can tune for AquaMist systems, although we will recommend it only on the Aquamist Series 2 systems which are more flexible. Its also better on the DBW cars

Water injection works well to reduce the intake temperatures significantly and is generally much easier to install than a new intercooler.

To gain more horsepower by using water injection generally involves changing the air-fuel ratio which is pretty simple to do but then if for some reason the water injection fails or more commonly you run out of water or like Gandalf have leaky reservoirs then you are faced with a situation where engine damage could occur because of lack of water injection.

However on a stock or tuned car the knock sensors are working quite hard with our bad quality fuel and generally there is some ignition retard occuring due to various factors such as changes in barometric pressure, heat, boost etc. add in water and the retard is gone and some gains are realised

The only way I would recommend you tune a car with water injection for more horsepower is to utilise a relay to switch off boost (quite easily done) controller when the water injection stops.

Happy tuning

Yeah, I've got that switch comiong as well, dont want to fry anything! I'll let you know how it turns out!
W