M20 2.0 tuning- a few performance mods

Wed Jul 15, 2015 5:06 pm

Hi guys, I'm running a 320 e30 with a totally standard engine. The engine has done 150k miles but still sounds quite sweet and doesn't burn oil. The car to be honest is quite slow but I still like driving it. I recently fitted a 'speedtouch' mild chip and to be fair for the money it made a decent diffeence to performance and I would actually believe the 7-10 bhp claimed increase. Recently I have got my hands on a 325 throttle body and will be fitting this soon. Has anyone else done this and how much difference did it make?
Also I will be fitting a lightened flywheel in the future. Has anyone else done this and if so how did you find the results. Thanks

Wed Jul 15, 2015 5:35 pm

The throttle body mod is a lot of work for little to no noticeable difference. The only way this becomes worthwhile is by also fitting a 2.5 inlet manifold and opening up the ports on the 2.0 head to match. However if you're going to go to that effort you may as well just fit a 2.5 engine.

Wed Jul 15, 2015 11:18 pm

Ok thanks for the reply. Don't really want to change the motor as not had the car long.

Thu Jul 16, 2015 10:13 am

Then just enjoy the 2.0 for what it is and forget about making it quicker. It's a decent if unspectacular lump.

Thu Jul 16, 2015 11:22 am

You can improve the 2.0 - and the 325i throttle body mod does work IF you increase the fuelling with an ECU remap. There are two ways of doing it - either open up the existing manifold or - better still - modify the inlet ports to accept a complete 325i manifold. It's a short stroke big bore engine with nice big valves and it's capable of more than 125 bhp. With the chip and manifold you'll gain an easy 10 bhp.

Thu Jul 16, 2015 8:13 pm

Ok thanks for that. I have the 'chipped' ecu so all I would need it to buy a new Inlet hose (325 one) and a a few gaskets so might give it a go.
Cheers guys!

Thu Jul 16, 2015 9:36 pm

Have you considered fitting a higher ratio diff ?

The 320i cabby ran a 4.27 diff which would give you a lot more poke.

Thu Jul 16, 2015 11:09 pm

Yeah it's a consideration. Thing is my car runs a small case lsd. Would involve a bit of work. I used to run a 4.4 medium case lsd on my old rally car with an e36 box. Maybe easier to just fit an e36 box to lower the gearing when the box is out for the flywheel. Balls this daily drive is starting to become another project haha!!

Fri Jul 17, 2015 5:24 pm

I would say do the 2.5 throttle body mod, I did it and it made a difference. I also fitted a speedtouch wild chip and had my flywheel lighten down to 6kg. Thoughs two aswell made a massive difference, I had the car RR at 121.9bhp at the wheels. With a 16% drivetrain loss it worked out at around 145bhp.

Fri Jul 17, 2015 9:06 pm

That's great results. Thanks for the reply a‘a