Tech me on m20 performance mods

[tsweers89]

Having never nodded a m20 I don't know were to start. Intake, chip and all that crap I think is probably not worth the money. I know FI is a good option but does anyone make a bolt on kit? Anyways I have a customer me a very nice 2002 that has a m20 in it that they track with. She is wanting some more power out of it. She was thinking stoker kit. I wouldn't have an issue with FI but then reliability comes into play and I'd want something that she wouldn't have to worry about. Any input would be great. I heard spec e30 guys get quite a bit of hp out of there NA m20s.

[TCD]

Steering linkage in the way for any bottom mount turbo manifold.  You can squeek 175rwhp out of a m20 n/a with a ton of bolt ons and megasquirt.

[Boris3]

Most SE30 with the m20 tend to fall between 145-155 hp on a dynojet. Series is capped now at 160.9 max. Before the cap there were some west coast folks on fresh rebuilds with the allowable 0.020 overbore and the stock ecu hitting the high 160s at the rear wheels.

Intake doesn't do much but a chip (conforti or a war setup with bigger injectors) can help particularly in midrange grunt. New MAF sensor can also help since the old ones tend to wear. Other tricks including choice of plugs, and lower oil weights have lead to very small hp gains for some folks.

Does the client just track for fun or in a race series? Matters in what can be done given classing rules. Also what tracks? Top end focus makes less sense for Blackhawk or Autobahn verses say Road America.

[B C]

In my experiences:

Best bang for the buck is a set of healthy M50 injectors (www.maksinjection.com) since they atomize better.

A MarkD chip has a very well optimized timing curve and is well worth the cost. I have tried the Jim Conforti chip as well, its good but I felt that the MarkD tune was slightly better

Do not bother with maf conversions.

Cone filters are very difficult to fit with the stock AFM. A k&n drop-in filter is fine, do not remove the intake trumpet upstream of the AFM inside the airbox lid or if you get rid of the airbox make sure you buy or make a cone filter adapter with a smooth transition. Most off the internet have no transition at all. Jeff on here has some that he makes.

The stroker builds with cams feel a lot like an e36 m3 feels, but with more top end pull if it is ported and has a large cam. Extremely fun reliable power, plenty for the street but would be boring for the typical freeway racer.

I like NA more than I like turbos but the thought of dropping a valve/breaking a timing belt and instantly wrecking a fancy ported head with custom pistons, valves and a grand or more in machine work is a huge turnoff.

This is why I went with a snail. Reliability takes a hit but its cheap and easy to get back in the game with a used stock m20

Chip, injectors, and maintenance are my first suggestions for someone with ~$500 to throw at an m20

[Boris3]

Yep sorry about that I should get my letters straight---meant to say new or refurbished AFM (from Gregs///M ) not a MAF conversion.

Also for the true cheap m20 fix make sure your throttle cable is adjusted correctly so that foot to the floor is actually WOT. Retaining nut can come loose on the cable. Guy in our group ran a race weekend wondering why his power was down. Turned out the cable had loosened. Picked up 10 hp on the dyno when discovered. Go figure.

[B C]

A quick check for that is to see if you can successfully do a stomp test

[tsweers89]

This is said vehicle. He is pretty much up for anything I recommend. I asked what is budget was and he said he didn't have one set. I threw out a $6k number and he said he was ok with it if it was the best choice.

[tsweers89]

Have not seen or looked over the car yet but he says it's rust free and already has track brakes and suspension. Will be seeing the car next weekend.

[tsweers89]

Steering linkage in the way for any bottom mount turbo manifold.  You can squeek 175rwhp out of a m20 n/a with a ton of bolt ons and megasquirt.

Well that's a bummer. Was going to give you a call as I think for the money a sarge 1 kit would have been the way to go

[tsweers89]

Also he does just does track days with it no competitive racing. He goes to the normal track around so small and big. Don't know if he uses it on the street or not though.

[B C]

What a sweet car!

[Rowleym]

I vote turbo! with that budget you could have an incredibly reliable setup, and even 300whp would be pretty insane in a 2002, and 300whp can be VERY reliable on an m20 on pump gas. very simple and at that power level nearly instant spool with the right parts. 

[tsweers89]

I vote turbo! with that budget you could have an incredibly reliable setup, and even 300whp would be pretty insane in a 2002, and 300whp can be VERY reliable on an m20 on pump gas. very simple and at that power level nearly instant spool with the right parts.

Problem being there is no bolt on kits for the 2002 which would make things more difficult and since it's only 2 of us at the shop we don't have enough man power to do a full on custom build and still keep up with the other customer work since we only work weekends

[HipMF]

A properly designed ITB setup will net some real, tangible horsepower gains. Packaging could be an issue though, as the runners tend to be pretty long when they're done correctly. The looks and the sound thoungh.... :eyesrollingbackintheheadfrothingatthemouthsmiley

 

http://racehead.com.au/products-page/bmw/bmw-m20-itb-kit/

[tsweers89]

It's most likely looking like it's going to be a 2.9L stroker with possible ITB's pending some tuning availability.

[B C]

If the customer is a goofball and doesnt mind coming in periodicly for a re-tune and linkage adjustment then ITBs could be lucrative, otherwise it could be a hassle to the customer to not have it running consistently due to the finnicky nature of Alpha-N tuning.

 

The money spent on ITBs could certainly go towards the higher CR pistons and larger cam that will be needed.

The Metric Mechanic pistons have valve reliefs that make the M20 a non-interference engine, even while increasing the compression ratio which would be a huge selling point if I were a customer.  

[tsweers89]

If the customer is a goofball and doesnt mind coming in periodicly for a re-tune and linkage adjustment then ITBs could be lucrative, otherwise it could be a hassle to the customer to not have it running consistently due to the finnicky nature of Alpha-N tuning.

 

The money spent on ITBs could certainly go towards the higher CR pistons and larger cam that will be needed.

The Metric Mechanic pistons have valve reliefs that make the M20 a non-interference engine, even while increasing the compression ratio which would be a huge selling point if I were a customer.

Very true on the ITB's. I'm still weighing my options. He saw a s50 2002 online and wanted to do that but after looking it seems like there is so much fabrication involved when doing that which I can not offer. Boy I wish this was a e30 at least. I don't think it's worth sticking $6k into it for a 2.9L stoker and ported head for at most 190whp.

[HipMF]

24v swaps are boring. Get creative!

 

 

Oh wait, this is reality, not my personal fantasy land. Sorry.

 

Would get some good reactions when you popped the hood, and the transaxle would keep the weight distribution where you want it. =) Someday, when I have a nice shop and a crap-load of money and free time...