Advice on mods after a remap - lost power :(

[rockafella8587]

Hi,

I had my 1.9 cdti 150 remapped at MAS at the begiing of the year and i was really happy with the difference in power and torque. Last weekend i had a custom exhaust fitted which has no backbox, the dpf was already removed just before the remap. So really all that has changed is that the backbox is now a straight pipe.
My car has definatley lost alot of power since i had the new exhaust fitted. Its defo the exhaust that has done it as it changed from that moment on.
Ive tried researching this on the net and some people mention the turbo will be overspooling now
I would lke to have the power back again, even tho my mpg has shot throught the roof lol
Will i need another custom remap to sort things out again with the new setup?
Any advice from somebody who knows what they are talking about would be very much appreciated

[Lean6]

What is the internal diameter of the exhaust?

[rockafella8587]

Same as the standard one whatever that was mate

[Lean6]

On a turbo lump, reducing back pressure is favourable. Unlike NA which can lose torque if too large a diameter pipe is fitted. The fact you haven't increased the exhaust diameter side almost rules that out. I personally can't see removing the backbox being a major issue. Did they reset the ECU after fitting the new exhaust? They did with mine. Perhaps the map has been deleted. Not too sure.

[GazVXLINE170]

On a turbo lump, reducing back pressure is favourable. Unlike NA which can lose torque if too large a diameter pipe is fitted. The fact you haven't increased the exhaust diameter side almost rules that out. I personally can't see removing the backbox being a major issue. Did they reset the ECU after fitting the new exhaust? They did with mine. Perhaps the map has been deleted. Not too sure.

Mine has no back pressure and runs fine.

[rockafella8587]

I really hope not! Why would they do that? If that's the case I won't be too happy with them I will call them in the morning I think.

[Lean6]

They sometimes do it to allow the ECU to re-learn and adapt to the change (even if slight) that an exhaust may make. Does your CDTi have a cat?

[rockafella8587]

It did have a cat/dpf bit that was removed at the same time it was remapped. It still has the pre-cat right at the front tho. I told the bloke it was remapped so hopefully he would not have touched it.

[plasma]

The worst the exhaust place would have done is to disconnect your battery whilst doing the welding work.... Mine felt less torquey after having my catback fitted from MIJ but when on the rollers which i have used previously produced exactly the same figures... Its that the car breathes more easily now all the way up to and into the redline and you dont really notice it..

1.9cdti with EDS remap to 186bhp, catback system

[Lean6]

Have you had the EGR removed?