E9X 335i - More power

[Sohaib-ijiiv]

Hi All,

Have a E93 335i which is standard apart from an Injen DCI which came with the car but hasn't been fitted on.

I was wondering what is the safest route to take with regards to increasing power whilst still maintaining my warranty?

Have read loads about MHD, JB4, COBB, JB+ etc and I am concerned if I went down that route BMW could invalidate my warranty if they were to find out it has been tinkered with. One SA at my dealership said its fine if I remove everything before bringing it in, another said its a no-no.

What would you advise? Looking to keep the car for a year or so.

Thanks!

[Mike335i]

No power increase is going to preserve the warranty on the engine / gearbox unless they are specifically approved to do so by the warranty. Did BMW do any power kits of this era? Even if they did I'm not sure they would still be available.

You could try and fool them by removing in the event of it going to the dealer, but there is a good chance you'll get found out quite quickly as they will be able to detect remaps etc. Using a standalone unit like a JB4 could work, but still risky. I assume whne you tell the insurer of the modification that they warranty company doesn't have access to that information, but I'm not totally sure.

[AB]

Have had a JB4 on my 435i since day one. It’s been serviced a few times and been in for warranty work too.

I removed it prior and nobody ever said anything. That’s not to say they can’t find out if they wanted to or suspected.

[Smokey32]

There isn't one. If you want to keep warranty, don't bother.