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Postby lovejags » Thu Feb 28, 2019 9:59 pm

Hi thinking of getting a stainless steel backbox and a remap at the same time for my 2007 xkr. Has anyone any recommendations.

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Postby J44EAG » Thu Feb 28, 2019 11:55 pm

Done two similar modes on my Jags over the years.

V8 4 litre S-type fitted with full resonator-less S-type R Miltek exhaust and ECU re-map. Both done at the same time about ten years ago by the then operating Paramount Performance at Slough. Absolutely no issues over the years I ran that modified car. The exhaust sounded great but could be a bit wearing on the ears if you traveled four hundred miles in a day. Don`t over do the noise increase. You may live to cuss it! The ECU remap made the car more flexible and willing to go. It was a bit like adding an extra cylinder. Driving a standard car after the mods were done to mine felt as if someone had stolen part of the engine. Well worth doing but don`t expect improved fuel economy.

Paramount later became Viezu and moved mid counties. Same MD, Paul Busby, ably assisted by the amazing ECU guru Gerald Morten. Gerald now runs his own Viezu franchise trading as Viezu Berkshire from Tom Lenthalls workshop at Finchampstead.

My next Jag to receive ECU and exhaust mods was my current XJR X350. Learning from my exhaust lesson, I just had the resonator box removed in favour of a gas flowed X-pipe arrangement but left the standard back boxes in place. The exhaust note is more vocal but quite acceptable for long distance work and I no longer get deafened. I also had sports cats fitted which are a double edged sword for a road car. A fast idle test has to be done at MOT time as the cats catch a cold on the inspection ramp and emissions go off the scale. Best advice...don`t fit sports cats. Longlife Exhausts franchise at Carlshalton in Surrey did my exhaust mods. No problem with the build quality but note negative effects of fitting sports cats. That was my bad decision alone and one that I won`t repeat.

After the exhaust was modded, I had Gerald Morten re-map the ECU. Again, extra cylinder effectiveness was added to good effect. It all adds to an easier running and quicker car which is still capable of running on normal pump unleaded petrol.

For power tuning mods on V6 and V8 Jags, see my thread on the subject. The thread is a sixty thousand word epic with images attached. Once you have read the thread, you will be in a position to decide what improvements can be made to your own car.
X350 Co-ordinator

2004 XJR

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