[Bailey238]

Hi all,
I have an n54 135i currently on an mhd stage 1 tune. I know these cars have issues with carbon build up and I'm reading that methanol injection can help with this. My question is, would adding a cheap universal meth kit help clean my valves and as a bonus give me a slight performance boost on the same tune all without any added risk? My friend says if I didn't change the tune there would be no risk since if meth stopped flowing it would be on the same tune it is now. Would I even be able to notice any performance gains without a more aggressive tune? My thought is I could spend $400 now on meth and get a little performance boost or spend $400 later on carbon cleaning. What do you guys recommend?
Thanks in advance!

[iqraceworks]

Yes, having a meth/water mix flowing over your valves will "help" keep them clean. But if they are already really nasty.....I'm not sure the meth injection alone is going to get them clean for you. Even spraying carb cleaner right on the valves doesn't do much to get that thick carbon buildup off....that's why people Walnut blast them.

But....I bet if you started out with clean valves, the meth would keep them cleaner longer....I guess it all depends on how much meth you are injecting..and how often.

As far as performance gains without a meth specific tune....you probably won't see much.

[Jeff@TopGearSolutions]

Originally Posted by iqraceworks

Yes, having a meth/water mix flowing over your valves will "help" keep them clean. But if they are already really nasty.....I'm not sure the meth injection alone is going to get them clean for you. Even spraying carb cleaner right on the valves doesn't do much to get that thick carbon buildup off....that's why people Walnut blast them.

But....I bet if you started out with clean valves, the meth would keep them cleaner longer....I guess it all depends on how much meth you are injecting..and how often.

As far as performance gains without a meth specific tune....you probably won't see much.

Last time I had my intake manifold off the valves had 50K miles on them with only about 1-2K miles of methanol spraying. I typically won't spray methanol daily as it's set to around 10PSI. That being said I'm still an enthusiast here and there.

Originally Posted by Bailey238

Hi all,
I have an n54 135i currently on an mhd stage 1 tune. I know these cars have issues with carbon build up and I'm reading that methanol injection can help with this. My question is, would adding a cheap universal meth kit help clean my valves and as a bonus give me a slight performance boost on the same tune all without any added risk? My friend says if I didn't change the tune there would be no risk since if meth stopped flowing it would be on the same tune it is now. Would I even be able to notice any performance gains without a more aggressive tune? My thought is I could spend $400 now on meth and get a little performance boost or spend $400 later on carbon cleaning. What do you guys recommend?
Thanks in advance!

You would notice gains just not nearly as much tuning for the spray. Methanol done for power would gain a stock car ~50HP.

Without tuning for it, it would just be whatever stage 2 you run with full ignition timing. Methanol is like Race gas + cooling. So you still get all the methanol cooling benefits of the intake air temps being lower and the octane increase of the "race gas".

It really depends on how much methanol you really want to spray to answer your question. Depending on how bad your valves are you may still want to get those taken care of anyway. I genuinely don't know how much they would clean excessive build-up. I started spraying around 45K miles and I probably checked them around 55K and they were still decent, not perfect.