b20 swap for b25

[maujo]

hi all,
im thinking of swapping out my b20 for the b25, but im wondering wether to get a high compression version or the low compression version?

Pros/cons?

Thanks

[maggspower]

What are you starting out with?

[Speedtouch]

I'd go for the high compression one, having tried both - the high compression has a nice crisp throttle response, whereas the low compression felt a bit 'flat', and that was with Megasquirt tried on both open and closed (Lambda-controlled) loop modes.

The only advantage I can see with the low compression one is that you can easily turbocharge it if you want to.

[gooner1]

I'd go for the high compression one, having tried both - the high compression has a nice crisp throttle response, whereas the low compression felt a bit 'flat', and that was with Megasquirt tried on both open and closed (Lambda-controlled) loop modes.

The only advantage I can see with the low compression one is that you can easily turbocharge it if you want to.

......and mate the HC lump with the later Motronic loom ftw.

[Speedtouch]

maujo's 1990 320i should already have that in place - just a question of swapping the engine and ECU EPROM chip.

[maujo]

If getting the high compression, higher octane fuel would be the way to go? and the chips, any chance of shipping to NZ?

[Speedtouch]

Any standard M20B25 should run fine on standard 95RON unleaded - there is no gain to be had from using high octane fuel with these engines.

PM sent.