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[Feeble]

Why do you suppose that my Brabus tops out at 125mph? It has been remapped to 200bhp (proven) and is still on 17 inch wheels... Is the supposed 137mph claimed top speed accurate?

[Coverman]

Road testers achieved it I think. It would be unusual for German manufactuers to overstate performance figures ( emissions, economy, oh well)

[Feeble]

Just another thing my car sucks at then! Haha

[mr singh]

are you running on premium or regular fuel?
when was your air filter replaced?
when were your spark plugs replaced?
what wheels are you running? are they the standard brabus cheese wheels? (although they shouldn't make a difference)

[Feeble]

Premium fuel, it has an induction cone style filter, though I am not sure how old that is. Spark plugs were done about 6 months ago. The wheels are Lenso Reizen 17s...

[Brabs]

You really don’t want a cone filter under the bonnet. It’ll be sucking in hot air. IMO. 😉

[Ocracoke]

The other thing I am thinking of is the age of the pipes leading to and the turbo itself. Are you able to monitor the pressure of it?

[Feeble]

Yes Brabs, that was my concern, but I liked the noise! Haha. So worth putting the original airbox back on for better performance then..?

Ocracoke, if I can do that by using the OBD2 reader then yes I do have the capability...

[cecil]

As the top speed was obviously tested at a circuit like Thruxton- you may not have had the time to get up to the full speed.

[mr singh]

agree with what cecil has said. if it was done on a race track, you may not have had enough straight to get it to its top speed. I drove to my aunts in South Germany and I managed 122 on the autobahn, although I may have got a higher top speed had it not been for traffic

[Feeble]

There was definitely enough straight road ahead at the time of testing. 125mph and no more to come... 

[cecil]

Questions to ask. How old is the cambelt? Is the clutch fully engaged and not slipping?Any trace of brake bind?All pipes tight with no trace of leaks, the turbo pressure pipe is an easy one to leave 'loose'? Plug leads and coil working correctly with no sign of tracking?
Tyre width and inflation, road surface, ? Has the suspension been modified so that the tracking is out, heights of the car are not correct? Wind speed and direction- these all could increase drag. were you going up a very slight slope?
 Finally a question that I am not sure about the answer to- is maximum speed in our cars achieved in 5th or 4th- 5th may be an overdrive ratio and not let the engine achieve peak power in that gear.
As the straight was long enough on the autobahn/ runway these are my ideas.

[jmariog]

If you find out what your gear ratios are then could you not work out what your revs should be and see if you can get them for 135 MPH. Maybe???

[Feeble]

Questions to ask. How old is the cambelt? Is the clutch fully engaged and not slipping?Any trace of brake bind?All pipes tight with no trace of leaks, the turbo pressure pipe is an easy one to leave 'loose'? Plug leads and coil working correctly with no sign of tracking?
Tyre width and inflation, road surface, ? Has the suspension been modified so that the tracking is out, heights of the car are not correct? Wind speed and direction- these all could increase drag. were you going up a very slight slope?
 Finally a question that I am not sure about the answer to- is maximum speed in our cars achieved in 5th or 4th- 5th may be an overdrive ratio and not let the engine achieve peak power in that gear.
As the straight was long enough on the autobahn/ runway these are my ideas.

Some questions I can answer. The clutch and cambelt are next to brand new as I had them replaced two months ago. No brake bind. I haven't checked the pipes yet, but that gives me something to look at. I dont know about the plug leads and coil or even how to check those. The tyres are 17/205/40 up front and 17/225/35 on the back and are at the correct pressures. The suspension is all standard as far as I know...

Does it seem reasonable that my induction kit is doing more harm than good..? The car does pull ok in the low gears, but it doesn't really feel like anything special most of the time! 

[cecil]

As your car was tuned did they install a BOV? A common addition for colts and seems to be a source of much discussion for us!. If you have the dyno figures(map) especially for the torque curve they could be useful to upload and might explain why it doesn't feel special.
 Hot air is less dense and will make the charge run warmer. The electronics will sense this and reduce the BHP to about 150- dirty or regular will do the same. Was the 'Super' fuel Shell- our cars seem to like that.