RS4 with milltek, without remap feels slow?

[sandymat101]

I fitted a milltek Tuesday night, non resonated non valved and it sounds fantastic, at first it felt just as quick if not a little better at lower rpms.

Only today I'm sure it's slower, I know it requires a remap with milltek but is the performance drop noticeable by the driver? Its not exactly slow but it's just not as rapid as it was, especially above 3rd gear.

Would the ecu adjust adjust things over time, explaing the Tuesday night rapid feeling?

Who's the best for a custom remap? I'm in the North West near Warrington and don't mind travelling.

I also fitted a BMC panel filter at the same time but didn't wash it, if the oil has damaged the MAF would I get a fault code rather than a performance drop?

[rAudiguy]

from my experience and experiments I estimate around 25bhp loss from fitting a Milltek without a remap!

[pippyrips]

I never noticed a difference when I had the same catback setup on my car and dyno'ed at SRR at 390bhp.

Admittedly my torque curve was lower in places than other stock cars but that could have been down to a number of other things.

Personally i don't think they cost you anywhere near 25bhp, lots on the US forums swear blind they actually give more power even without mapping.

[sonny]

I noticed a great deal in drivability when i fitted my Miltek, however I did have a GruppeM filter, what mileage is your car? I had mine fitted on 24k

[sandymat101]

21k is the mileage, late 07 car. I've done maybe 200 miles since fitting milltek on Tuesday.

It may well be torque rather than power, it doesn't climb the revs as quick as before really noticeable in 3rd.

[Gazzer68]

The standard ecu "maps" are written for the cars setup, i think it would be foolish to expect the car to run better or the same when you make changes as significant as an exhaust gas flow rate.
This engine is very complicated, i dont mean internals, but all the electrical bits, sensors/vacuum actuators etc
The ecu measures everything, not just for performance but also emissions and fuel consumption, car makers have this to consider more than anything else these days !
The only way forward is to have a custom remap, a generic map would be pointless, we all now know (re:RR day), every rs4 is different.

[Oli]

Remember also the ECU will take time to adapt to a change i.e. new exhaust, 200 miles might not be enough.

Also these cars are known to have fast and slow days, as reported by many of us - Mine is just having a slow day every day!

Once my car is sorted and I start changing bits, I am aiming to check the power differences to accurately assess what is what, I believe Jim is the resident expert on changes and what difference they make, but as we all know each car performs differently

[sandymat101]

I did plan on a remap but I didn't expect to notice a drop in performance, i'm just a bit surprised how noticeable it is.

Would it take a while for the ecu to adjust, it's not instant?

[sonny]

I drop in BHP (on the rollers would be expected due to the nature of the engine) on the road however should be a different story, I would go for a remap, maybe one at MRC have it written to the fuel you use.

[sandymat101]

I'll give MRC a ring tomorrow and book it in, I use shell V power about 2 miles from stanlow refinery and a busy station so should be good.

Could do with a dyno at home in the garage, make things easier with these cars

[psg001]

i never noticed a performance drop after fitting the cat back milltek on mine.

[wrekka]

I fitted a milltek Tuesday night, non resonated non valved and it sounds fantastic, at first it felt just as quick if not a little better at lower rpms.

Only today I'm sure it's slower, I know it requires a remap with milltek but is the performance drop noticeable by the driver? Its not exactly slow but it's just not as rapid as it was, especially above 3rd gear.

Would the ecu adjust adjust things over time, explaing the Tuesday night rapid feeling?

Who's the best for a custom remap? I'm in the North West near Warrington and don't mind travelling.

I also fitted a BMC panel filter at the same time but didn't wash it, if the oil has damaged the MAF would I get a fault code rather than a performance drop?

I thought a remap was only needed if you changed the cats? No-where does milltek say you need a re-map just for a cat back? This is concerning now as I'm almost about to part with my hard earned cash for a non-res, valved one but thought the standard ecu could cope. Don't know whether to risk it now then....

[Dom81]

This is just an old (and fairly isolated) post resurrected by that spamming <beep>. MRC told me there was no need for a remap when they fitted mine, and it both feels and measures slightly faster since the work. The sound is in another league, and the more free-flowing nature makes downchanges a dream. Don't worry!

[wrekka]

This is just an old (and fairly isolated) post resurrected by that spamming <beep>. MRC told me there was no need for a remap when they fitted mine, and it both feels and measures slightly faster since the work. The sound is in another league, and the more free-flowing nature makes downchanges a dream. Don't worry!

Cheers, yeah there's his spam in loads of threads now!

[PetrolDave]

I thought a remap was only needed if you changed the cats?

Any fitment of a freer flowing exhaust will tend to weaken the mixture (due to the greater purge of spent exhaust gasses), so remapping after fitting a Milltek or any other freer flowing exhaust is "a good idea".

Posts here previously have suggested that fitting a Milltek can cut the power by 5-10bhp, which a remap more than restores.

Milltek don't say a remap is essential because the aim of their exhaust is not to increase power.