Putting in a new radiator into my 03 VIII I saw that the original owner had adjusted the preload on the WG (I think the car had an EBC at that time). I was wondering how this would affect performance, and if I should update my tune (now a mail in) for it and the addition of a high flow cat & catback to boot.

 

If you mess with the preload you are in turn messing with the boost level. With the addition of a high flow cat and catback yes you will need a retune. I however don't suggest mail in flashes.

 

The EBC was gone before I got the car and the standard boost lines & pills have been in ever since. I usually see a peak boost of 21psi, sometimes a bit less if its hot and humid. It has good mid range throttle response, but the upper throttle to WOT is rather bare. I'd like to see about getting it improved; right now it has a Dynoflash mail in with a K&N drop in as the only other mod.

 

I am curious as to what specific visual clues led you to conclude that the previous owner had tinkered with the WG preload.

EDIT....Duh, I just saw the picture in the opening post. Why dont you just install a new WGA? That one looks kinda abused.

 

In the pic there is a red hose connected to the WGA nipple. That is not the stock factory boost hose assembly. So, what do you mean by standard hoses?

 

that red part is part of the stock hoses. it is just the tip painted