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Discussion Starter #1
Hi, new to the forums and M3 ownership although had a 330d for several years. Just bought a 98 M3 Evo with a mate to use for track days only. Seems to pull well on the road but having never driven one before can't compare. Decided to dyno it to know where we are starting from power wise and was hoping for 300bhp at best but hopefully over 290. Was shocked and dissapointed to find only 255 BHP at the flywheel! 70 BHP down seems way too much and must have some problems?

She's done 80k miles, small rumble from the vanos but nothing much. I read vanos should provide a kick at 2.5k and again at 5k rpm. The dyno chart shows only a flat spot at 3.5 k and a pretty linear increase in power both before and after the flat spot. If the kick is that noticeable I would have thought it should show on the dyno graph?

Dyno tech did the first run in 5th and then best run in 4th but was nervous as we still had a 130mph road speed, didn't try a lower gear.

Any guidance anyone could help with would be appreciated. Cheers!
 

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Discussion Starter #3
I've got limited info on the recent history, car hasn't been used for 3 years, basic service done today myself, service lights are all green at the moment. I don't know how to establish if the cats are ok to be honest.
 

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You shouldn't feel any obvious kicks from the vanos, that was only a VTEC thing where they flick on or off.
The M3 Vanos is constantly adjustable to any point.

I'd look into a mix between a fault code somewhere (bad lambda sensors, MAF etc) Jammed or sticky vanos, and valve clearances.
 

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I don't know much at all about the E36 M3 although i was talking to a friend of mine about two weeks back about E36 M3 and he was saying one of the must do's is to keep the valve clearances right. ^^^ As "TheEnd" said.
 

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Discussion Starter #6
Thanks for the comments so far, done some investigation today and I think I've found where some if not most of the horses are going. No 6 spark plug threads are completely stripped, plug was only finger tight and spark plug recess full of dark powder from burnt gasses escaping. Good news found a problem, bad news it's a big one! Apart from a bodge job I guess I'm looking at head off, re- tap or helicoil or new cylinder head?

Only owned it a week.......happy days!
 

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Discussion Starter #8
Thanks for the offer. Have a track day in 2 weeks so won't be hanging around to sort it out. Could I pick up I'm only an hour away from Birmingham?
 

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Discussion Starter #10
Update if anyone's interested. Got lucky for once! Number 6 plug was hardly screwed in, threads damaged but managed to recover them, fitted new plug, straight on the same dyno and 302 HP. Happy days, 50 HP for £10! Strangely doesn't feel that much faster.

Done two track days and now got a new (smg) problem. After running for a while and I guess good and hot get an embarrassing neutral when changing up from 3rd to 4th, doesn't happen all the time and I haven't figured out a pattern yet. Doesnt matter if its auto or manual get same results. Anyone else heard of this one? All othe selections are fine.

For info got the complete black leather interior removed if anyone's needs anything.
 
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