lower than normal boost

[20Vcqdriver]

How much of a boost leak would you need to get a 0.1bar lower boost than normal? Or does boost change depending on weather/outside temperatures?

[UrS4boy]

How much of a boost leak would you need to get a 0.1bar lower boost than normal? Or does boost change depending on weather/outside temperatures?

Cooler air is more dense than warmer hotter air. It is also less likely to cause detonation (pinging). As a result, in theory, you can add more fuel (and boost) to the cooler air and make more power as air temps decrease. This is why we add bigger intercoolers to our cars.

However, the OE Motronic ECU is programmed to actually decreases the max boost at cooler (colder) temperatures so that the performance of the car remains the same over the entire year, even though the cooler air has more potential for higher horsepower. I do not know if aftermarket chip sets, e.g. from MRC, do this as well.

[S2central.net]

That 2nd para is only true for some ECU types... Its definitely true for ABY & AAN, but the ADU chips will make more power with colder air in factory trim. From memory - so does the 3B.

[Rusty]

Some boost gauges are off, mine is... Get a calibrated boost gauge before you get too worried?

[HPmuirt]

Some boost gauges are off, mine is... Get a calibrated boost gauge before you get too worried?

I am told the VDO ones are good

Qu for Paul: What does your homefries do? Does it act like the stock ABY or hopefully more like the ADU?

Cheers n

Si

[S2central.net]

Sigh - Homebrews take the ABY approach on that - just not as simple as you'd think to dial out the dopey temp compensation by comparing to ADU... ABY method is safer option for all concerned of course - as Ingolstadt intended you might say. I'm trying to solve this for Ocifier Casey and others to make best of bigger/better intercoolers for one thing.

[HPmuirt]

Sigh - Homebrews take the ABY approach on that - just not as simple as you'd think to dial out the dopey temp compensation by comparing to ADU... ABY method is safer option for all concerned of course - as Ingolstadt intended you might say. I'm trying to solve this for Ocifier Casey and others to make best of bigger/better intercoolers for one thing.

Add me to that list then as I have an RS2 IC to fit

Cheers n

Si

[Rusty]

But we all know that you having parts to fit and actually fitting them are two different things, separated by months and years

Paul's been looking into this for a while and I'm sure he's making good progress, be nice to have a 3xx power figure to show everyone down the local... not that I drink or indeed go to the pub any more Got to be there now, the car feels stronger than ever and I've still got toys to go on. When they're fitted and I'm up to the tri I'll get to my local and trusted RR at Combe.

[Jamo]

That 2nd para is only true for some ECU types... Its definitely true for ABY & AAN, but the ADU chips will make more power with colder air in factory trim. From memory - so does the 3B.

Ah and there is the answer to a question I had, found out my car has an RS2 ECU i'm now very happy

[20Vcqdriver]

Reason for original question is that car has slowed down noticably over the last few months and intermittently performs as it should and other times slower than the heavier S2 with this 6 speed gearbox and noticed boost had dropped slightly on my gauge that always used to show at least 0.85bar... Think I need to get codes read..Seems to take a while to spool turbo too, even if revs are over 2700rpm when I floor it. But thats been an issue since install!!! Driving a standard S2 might help as not sure what are the normal characteristics for these engines.

[20Vcqdriver]

Found

Found issue with my car once it came off the road for its winter SORN, took off all the vacuum pipes and found the one from the manifold to the T piece that feeds the regulator and ECU had completely perished and with a massive split in it. How much would this small pipe affect performance? Explains the lower boost gauge reading as it is T'd off the ECU hose.