[dave23572]

From the OP:-

I thought I'd share the results of my further mods:-

To go with the Janspeed manifolds and ITG Maxogen, I've now added a Janspeed sports cat, Custom "Longlife" freeflowing cat-back exhaust and had it re-mapped.

The re-map and the custom exhaust were done at AmD Tuning in Thurrock (they run a BTCC car!).

Unfortunately the before and after dyno runs aren't 100% comparable being different dynos, but probably close enough.


Dyno results

Dyno run 1 ("Before") (ITG maxogen only)
Dyno: AtSpeed (Rayleigh, Essex)
179.7BHP
168.7lbft
Given the standard car was 175BHP, it would seem the ITG gave me about 5BHP.


Dyno run 2 (Added Janspeed manifolds, Janspeed sports cat, custom freeflow cat-back) (NOT re-mapped)
Dyno: AmD Tuning (Thurrock, Essex)
187BHP
172.4lbft
This seems to show that the manifolds, sports-cat and free flowing exhaust are worth about 7BHP, before re-map.


Dyno run 3 (As run2 (Re-mapped)
Dyno: AmD Tuning (Thurrock, Essex)
194.5BHP
179.5lbft
Proof that re-maps do work, Added around 8BHP

AmD say it may develop 1 or 2 more BHP as the ECU adapts further.


Conclusion
The increases were more or less what I expected.
To get more would have needed a de-cat I suspect.
I didn't go down that route as I wanted to stay legal and also I didn't go for a loud/big exhaust as I don't like that sort of thing. That's why I went for a custom exhaust, so I could spec it to be as quiet as possible with a fairly standard looking tailpipe.
It's still a little noisier than I would like but will be OK.

On the road
It does feel a bit more powerful on the road, from 3500 onwards. Not to the point where I could say it's transformed the car but a noticeable improvement.

Total cost for all parts (except the ITG which I fitted a year or so ago), fitting and re-map was around £1400.
Was it worth it?
All things considered I'd have to say probably no, but I've done it now so I may as well enjoy it.
It was an itch I'd wanted to scratch for years and now I have. If I hadn't it would have continued to bug me.

Tuning the KV6 is expensive for relatively small gains, but with the other mods I have, I now have a pretty nice 180. Looking forward to getting it on track in 2015 with my new trackday tyres.

I really wish someone had developed a much better plenum manifold, I suspect there could be good gains in that area.


Dyno graphs attached:-