tuning box or remap

[oneday]

hi im thinking of having the c5 tuned in someway in the next couple of months mainly for more pulling power at lower revs and to try and remove a flat spot right at the pulling away point.

im looking for advice on what is the best way to go tuning box or remap. recomend companies or or types

[waynedance]

I had a flat spot when pulling off just for a split second tried all sorts and only thing that worked to my amazement was a bottle of Forte diesel treatment.

I did look in to a remap or tuning box and from my research many seem to prefer the remap, I did nothing in the end as I wanted to keep standard.

[Mandrake]

If you've got a flat spot there must be something wrong, and it may be causing a lack of low down power as well. I'd be trying to find and fix that problem first before attempting any modifications...

[CitroJim]

For this, the MAF sensor may be worth looking into.

Has it had a session in consultation with a Lexia? You may also have a small boost leak as well. Intercoolers are a known weak spot on these and if they're oily at their base then they are leaking.

As for tuning box or remap; neither. Both are a complete waste of time and money in my very personal opinion. Citroen spent millions getting a good map and I'm a great believer that a remap might do something seemingly to advantage in one place but may well detract in another. As for tuning boxes, these usually work by upping the injection pressure and I have a belief this puts stress on the high pressure components that may result in early failure.

Get the basic faults sorted and I'm sure you'll find happiness without resorting to remaps or tuning boxes.

[Lighty]

One of my customers fitted a box on his C5 2.0 16V, it was not a cheap one, about £350. The engine light came on straight away almost, and he had to keep moving this peg in it to reduce power, started at 10, and ended up at 2. When he towed his van, it was covered in soot, he could see it smoking in the mirrors. The box has been removed now, and all is good again. When I drove it, I couldn't tell any difference tbh, although previously when testing them I thought they were quite good.
He seems to think economy was better. but generally I would not recommend it.
Perhaps this was a one off, but the company haven't been much help.

[oneday]

seems like you guys were right again. just checked the intercooler and the bottom is oily looks like a new intercooler is required thanks fot your help again

[myglaren]

Just got my C5 back with it's new intercooler. No appreciable difference although it is now far better than when I bought it in April.
Throttle cable slack taken up.
Turbo and vacuum hoses removed, cleaned, checked for leaks and re-fitted.
EGR valve checked and cleaned.
MAF (almost new) cleaned.

The difference after that was quite impressive but not so much as the outgoing estate. They did more or less the same procedure on that and the performance is almost scary, it will leave a BMW 320 diesel standing. If someone would fit some decent tyres to it it would be amazing.

[oneday]

going to change the maf aswell. allready cleaned the maf did make a lot of differance. its just the flat spot as i pull away thats anoying me seems to have loads of power once it gets going. going to put it on the lexia later and have a good look at it to see if anything else comes up

[myglaren]

going to change the maf aswell. allready cleaned the maf did make a lot of differance. its just the flat spot as i pull away thats anoying me seems to have loads of power once it gets going. going to put it on the lexia later and have a good look at it to see if anything else comes up

Could also be the MAP - indicated as a fault on the estate but a new MAF made such a huge improvement that I never ever got round to replacing that, then my son redesigned the car a bit.

[oneday]

thanks i,ll check that aswell. any advise is welcome