T4 custom downpipe + race cat

[timway]

Hellooooo Volvo tuning experts

I've been thinking about getting a custom 3" downpipe + race cat for my T4 for a while now. My budget won't quite stretch to an off the shelf one like BSR or Ferrita, but I have found a place fairly local to me near bristol: http://www.infinity-exhausts.co.uk
which has quoted me approx £350 to make up a custom 3" dp + race cat.

What I'm wondering about is:

1 I've heard you normally need to get a custom ECU remap after fitting a dp+cat - is this just to get the best out of it or to prevent running problems/boost spikes - or both? (i.e. if I get the dp fitted but don't get a custom remap straight away could I risk damaging Vilma's engine??)

2 Is there anything I need to ask for/specify regarding the dp+cat, apart from it having 3" diameter, no sharp bends etc...

3 Is it really going to make that much difference?
On the MTE website it states 230 bhp for a Stage 1 (Remap+Cat back exhaust) and 255bhp for a Stage 2 (Remap+Cat back exhaust + downpipe+race cat)
- so thats potentially an extra 25bhp just from the downpipey bit??

thanks for any suggestions anyway....

[smartbomb]

Hi Tim.

1. As with most hardware changes, an upgraded map is usually a given. A pain in the a**e, I know, but then we could all have chosen easier, cheaper hobbies....

2. Make sure they connect the lambdo sensors!! And the flexible section!! I know a guy with a Calibra Turbo had this done, missed out the flexi-bit, and the first time he booted it he cracked the welds, then spent a week trying to figure out where he'd gone wrong. Tosser.

3. Best bet for how much difference it's gonna make is to talk to a certain doctor, not a million miles away from you....but yeah, you'll notice the difference. 25bhp extra is probably a bit conservative.

Cheers
Paul

[pyaap]

Hi Tim,

For exhausts, I'd also recommend having a word with Longlife who are also just outside Bristol. They've done several T4s that I know of. Just get them to make a 3" downpipe with as gradual a bend as possible so that exhaust gas flow remains good. Do ask what type of race-CAT they use because that's going to be the most expensive component (that is mainly what you're paying for in a Ferrita system - an excellent quality CAT). A 100-200 cell CAT will be ideal.

The EMS2000 system is VERY sensitive to exhaust back pressure and by changing the downpipe, you will significantly reduce back pressure (esp since you've changed the CAT-back as well). Hence, you will probably experience boost spikes during up-shifts but you're not running huge boost and stock T4 rods are pretty strong. However, its detonation that I'm concerned about and you may actually find that fitting the downpipe with standard software causes a loss of power due to the ECU over-compensating for the boost spike. You ideally need stage 2 software on your car; it does not necessitate custom software (although that could potentially be beneficial in extracting the best from the engine, if done correctly). I suggest getting in touch with Jacq (V6en) as she had a similar setup and got 260bhp from it. Hence, bottom line is my advice would be to get the downpipe fitted just prior to getting the stage 2 / custom software upgrade done so that the car will continue to be reliable and you can enjoy the gains of the exhaust system. If boost spikes do occur and it concerns you, there are some rudimentary adjustments which can be made to temporarily reduce boost until you get the software done.

[timway]

Thanks for the advice!

I didn't realise Longlife did downpipes as well - I'll definitely give them a call in that case.

I wasn't planning on fitting the downpipe without ultimately getting a remap, just wondering if I needed to get the remap done as soon as possible afterwards really. I suppose if its a custom remap I'll need to arrange it so I get it done just before one of Marco's visits

cheers!

Tim