Question for a mate

Post Sat Feb 24, 2007 6:10 pm

Wasn't sure where to post this, as it doesn't relate to an engine swap or FI, but it's to do with engine tuning.

Anyway, a friend of mine has a 320i, and is after more power with the original engine (it's low mileage and he likes the originality)

He's considering Jenvey ITBs, but can't seem to find much info about them on the M2. I suggested a turbo, but he prefers N/A power and the noise of ITBs is amazing, especially on a 6 cylinder engine.

Is there a manifold available off the shelf? (DCOE pattern)

Am I right in thinking the CR is 9.8:1, or is is 9.2:1? (From what google has found me, the 'i' had the higher CR, the 320 (no 'i') was the lower one, so if anyone can confirm this, that'd be great

)

Also, what kind of power would he be expecting with a decent cam and exhaust manifold, plus the ITBs and top quality mapping?

Finally, if anyone has any pics, post them for us all to see

Sorry if it's the wrong area

Post Sat Feb 24, 2007 6:13 pm

Build a 2.7 or 2.8 and then go ITBs lairy cams etc.

Seriously i wouldn't bother tuning 320 as most people will tell you.

Even a 2.5 is a massive improvement but seriously dont tune the 2.0

Post Sat Feb 24, 2007 6:19 pm

How do you build a 2.7? 2.5 block, some random head? or expensive new crank/pistons etc?

Post Sat Feb 24, 2007 6:21 pm

525e bottom end with 320 or 325 head but 325 head needs machining work.
Or diesel crank i think. or 525e i think. with 320rons/pistons i think??

Post Sat Feb 24, 2007 7:28 pm

For an instant 50 bhp gain fit a 320i head with 325 cam/inlet manifold/injectors/fuel pressure regulator and airflow meter to an e28 525e (not 525i) bottom end.

The sump/exhaust manifold/water pump/flywheel/timing belt covers/front crank pulley and associated engine management bits will need swapping over. You'll also need to fit a spigot bearing into the gearbox end of the crank as all 525e's were automatics.

You'll need a 2.7 zone chip to get the fuelling and more importantly the ignition timing right. The 2.7 chip should fit into the existing motronic 320i ECU.

This'll give shed loads of torque and approx 180bhp.

Cheers,

Iain T