E30 Zone

What's the best way to get more torque on a B2O?

Was thinking of chipping or an enlarged throttle body but is this worth it for this engine? Any noticeable gains to be made?

Btw the engine stays, no conversion suggestions thanks very much

b20 has the shortest stroke so not ideal for torque, 325i 323i are longer stroke


Torque demands more restriction on the intake runners and longer runners so you could make a custom intake for about 5NM or swap the engine for £300

Any particular reason the B20 must stay?
An M20B25 would be a bolt in swap and be the cheapest and most reliable torque increase you could find. And it would still look like a B20...

It's been such a well looked after engine, thousands spent in dealer service history.. in it's life it's not gone 6 months without an oil change and under the rocker it's as clean as you'll find.. so would be a shame for it go.

I like everything stock and would easily keep as is.. but was wondering if there's any quick fixes that would be worth doing.

Ah fair enough, that makes

My b20 was toilet, well looked after and ran really well but when I was burned off by a shitty Clio up a hill I had to upgrade. It pulled really well above 4k but apart from that I didn't feel it returned enough for the fuel it drank. I changed to a lovely b25 which was much better, I got bored out throttle, (not much difference) Speedtouch chip, (nice boost) and all new bits ie gaskets, seals, injectors cleaned etc. I now have this for sale by the way as am swapping in an M52 now.

bosers wrote:when I was burned off by a shitty Clio up a hill I had to upgrade.

Haha I've been there a few times trust me!

For enhanced torque, do NOT fit a big bore throttle body (BBTB)! It's all down to the Vortex effect, which states that a smaller diameter air intake/throttle body will give increased airflow, which gives good torque at low rpm.

This is particularly important on lower capacity engines, to give a good bit of bottom end grunt and better fuel economy.

If you look at most OEM small car engined setups, they usually use long intake tracts and small carbs/throttle bodies for just this reason.

I looked at all the options for making the b20 faster & in the end I could have spent £1000 on the engine but it still wouldn't have had the power/torque of a b25 so in the end I got a b25 swapped in.
I still have the original engine but I can't decide on wether to build it up to a b28 or save up & do a M52b30.

The cost vs bhp/lbft on the b20 is prohibitive in my opinion.

i'm sorry but a b20 naturally aspirated engine will never ever have enough torque to satisfy anyone. as above this is why people ditch them for m20b25 and why people with m20b25 build strokers or ditch them.

I had various attempts at getting my b20 a bit more lively but nothing made a noticeable difference. I ditched it for a b25 after many years, which is obviously quicker, but nowhere near as much as I was expecting from all the hype it gets.

Thanks guys.. you've all pretty much confirmed my original suspicions.

I shall continue to plod along with my trusty B20, getting burned out by skodas..

I had a spin in Barry's Tech 2 the other day, and got an itch for it... but it'd be sacrilege to pull this engine out. If the engine ever dies (maybe in a couple of decades time) then I'll go all out with a conversion

put a B28 bottom end in the B20?

You would be able to keep every thing bar your crank, rods and pistons and have the block bored to 84mm.

There is pretty much nothing you can do to a B20 that will help much, the crank stroke is F1 car short.

I know how you feel, I was really attached to my 318i, hail damage to the car changed my plans, but I did look at chipping the 1.8, extractors and also replacing the afm with a maf, with some good gains and not needing to pull the engine down, below is a link for maf & chip kit, if later you change engines, keep the maf, you just need the appropriate chip to suite.

https://www.millerperformancecars.com/s ... mbo-detail

Mitchen wrote:What's the best way to get more torque on a B2O

Turbo

Supercharger is better

Just build an M20B28 and be done with it

DanThe wrote:Supercharger is better

Just build an M20B28 and be done with it

My M20B27 cost a lot of money and wasn't as good as my M40B18 turbo.

Fitting M52 would be cheaper and better

Agree, get a b28 crank, rods and pistons with proper mapped chip and hail the extra power