A4 B9 Performance upgrade

[Melgamma]

I'm proposing to get an A4 B9 Quattro, there is a version here in Mexico that delivers 252hp stock.

Obviously it's hot down here and 91 octane gas is the best I can get on a regular basis and for various reasons I don't want to mess around with fuel additives. The car will be used on the street, not the track. So I'm thinking of adding an intercooler, cold air intake, headers and exhaust and then have the ECU remapped. I gather that this is also a good time to replace the diverter valve.

Has anyone done anything similar to this? Whose parts would you recommend and what were the results?

 

[obi_waynne]

A front mounted intercooler works really well but is a challenge to get it to fit, the S3 intercoolers have been used to good effect, and I've even seen a twin setup.

The stock diverter valve can be a weakspot so it's worth upgrading but don't dump air to atmosphere, keep it all in the system or you'll get error codes.

The remap is the biggest and best option out there for these engines. The other parts won't actually make that much more difference but will probably cost 3 times as much as the remap.

A sports catalyst will help lift power, I would also be tempted to look at turbo upgrades, there are better options out there now which spool up faster and pull for longer in the rev band.

 

[Melgamma]

Can you recommend Brands for the inter cooler, DV and sports cat?

 

[kloyd1234]

Just join this great site, and purchased a A4 B9. My desire is to up grade the car performance. Is the new dn pipe and cat much louder? If so how much so...would also like to lower the suspension and put 19" tires on..ergo concerned about the possible rougher ride...looking for answers on performance up grade, dn pipe/cat sound and proper suspension for comfort and proform. thx kel

 

[obi_waynne]

Hi there @kloyd1234 good to meet you. Always a pleasure to meet a fellow Audi owner.

I personally wouldn't fit anything larger than 18's on an A4. My old A4 Avant Quattro was running on the Le Mans style double spoke 5 arm alloys and this worked quite well but was still harder than the 17's I used to have, but they didn't look right in the arches.

If you do need to go with 19's make sure you get the lightest ones you can find, it will help reduce the unsprung weight.

Bilstein H&R and AP make pretty good sets for the A4 and outperform even the S line setup from Audi. A 40mm drop from standard or 20mm from S LIne would suit the car nicely.

I am working on some newer articles for the A4 so stay tuned as these will cover in depth many of the topics you've raised here.