Opel/Vauxhall's unconnected socket in the engine bay

[Alexander Wenning]

Sorry for the late answer, but I was really busy.

martin at mgass.demon.co.uk schrieb:

> Out of interest how do you go about changing the maps ?  I presume 
> you use a laptop PC connected via the ALDL with suitable software.
> Do you have any problem with prom checksums ?
> Roughly how much bhp gain could you get at top-end?

Yes, we´re emulating the software via laptop PC but I´m not allowed to give any 
details about this. We usually get a performance increase around 6-8 hp.

> Also what are your views on the current 2.0 16V tuning wise, I believe that
> they are a lot down (power-wise) on the earlier (approx. 1990) incarnation 
> in the Astra GSI/GTE.  I understand that the cams are set roughly 
> the same but that valve sizes have been reduced and angles altered.
> I also understand that the current engine was a disappointment for 
> Touring car racing and that the earlier engine has been 
> re-homologated by running off a small batch of Vectras equiped with it.. 

The performance secret of this engine is the inlet! Fit a single butterfly 
arrangement with some nice cams and you´ll have around 180 bhp.

> I am not sure I understand this... are we saying that at full 
> throttle the mixture is normally rich to preserve the cat ? and that 
> the tune is to allow a period of leaner running followed then by a 
> rich period to keep the cat happy ?
> I also observe that if one were to remove the cat then it would not 
> be necessary to have a rich period, because there is nothing 
> downstream to get damaged, also I presume you could go to the optimum 
> lean setting ? 

A rich mixture can´t be burned completely so the unburned fuel parts can cool 
the cat to prevent overheating. Without a cat you don´t need a fuel mixture 
period. I suggest 12,6:1 at full throttle for non turbos and 12:1 for turbo 
cars.

Regards 

Alex.