M20 2.5 throttle body on 2.0?

Tue Aug 21, 2007 4:24 pm

Im sure its been asked meny of times, but i cant find anything on here.

is a 2.5 throttle body larger then the 2.0,..if so will it fit?

Also the same for the inlet manifold?

Cheers, Jason

Tue Aug 21, 2007 4:58 pm

I'm sure someone used to have aquote in their sig along the lines of...

"If you're going to fit a 2.5 throttle body, leave it attached to the rest of the engine and drop that in instead"
- Brianmoore

Tue Aug 21, 2007 5:00 pm

lol quality, got a good point though.

If the 2.5 lump is as easy as it seems and people say. then i might aswel do that.

Cheers for reply mate

Tue Aug 21, 2007 5:02 pm

Yup, it's bigger, it's been done & it's a worthwhile mod. Of course, a 2.5 is 'more worthwhile' but there's plenty of reasons why you wouldn't want to do that!

IIRC, you need to either port the 320i inlet mani to the 325i tb, or fit the 325i mani too, & port that/the head. Andyboy did a li'l writeup on it a while ago...

Oh, & I'm fairly sure I've got a spare 325i tb...

Tue Aug 21, 2007 5:03 pm

it is that easy i just did it

Tue Aug 21, 2007 5:05 pm

yeah man it should fit but if your going to do it......

i went from a 320 to a 325 ad teh difference is

both great engines though but the b25 is much much better. see if there is a zoner near you with a 325i and ask them with a smile if you can have a ride in the 325

but get plenty of advice and have a good read about the engine swap as it may be easy to some people with lots of tool but if your not a hero driveway machanic it wont be an easy change.

Tue Aug 21, 2007 5:30 pm

Ok cheers for that guys. Done a few conversions and mechanics for years so sure it wont be a trouble.

I can do porting and polishing too so enlarging inlets isnt a problem, just wondered if the 2.5 TB is bigger to start with.

Will probably fit the TB and port it too. just for the time being.

Ziggy - how much do you want for the TB? inc delivery.

Wed Aug 22, 2007 9:08 pm

And fit a chip from A Tech to go with it.

Wed Aug 22, 2007 10:29 pm

How much is a chip from A Tech, Bmw's are new to me.

What chip is it?

Thu Aug 23, 2007 12:40 am

chips are about Ã‚£65 and realy are worth it (but no personal experiance of that yet.)

will be swaping mine from a b20 to a b25 this weekend and am in reading fairly regularly so ill let you know how hard it is, what the difference is like and may be about so you can see for yourself at some point.

Tue Sep 11, 2007 4:04 pm

Cool would like to go out in one to see.

Update on mine:

Have now fitted the 2.5 throttle body and ported the 2.0 inlet manifold to suit. also fitted the new 2.5 AFM pipe to match and by passed the throttle body heater pipes.

BUT my dizzy cap and arm has got worse and is holding back all the way up the rev range so annoyingly,.. i cant even notice how much of a difference the 2.5 TB has made yet

I must say,.. the metal oil pipe on the bottom of the inlet manifolds is a pain in the backside when you havnt done one before, god knows what the neighbours thought at one stage when i was standing on my rocker cover F'ing and blinding

Anyway,.. It should be on the RR in october so ill let you know what difference it makes without a chip. but also,..where do i get the Chip from?

Tue Sep 11, 2007 5:51 pm

E Mail Ant from A Tech he is on here. >> http://www.e30zone.net/modules.php?name ... ofile&u=10

Tue Sep 11, 2007 8:58 pm

bugger forgot about this and i was in reading at the weekend.

Wed Sep 12, 2007 12:08 am

JasonK wrote:
I must say,.. the metal oil pipe on the bottom of the inlet manifolds is a pain in the backside when you havnt done one before,

Next time you do one, tie the spring down with a couple of small cable ties, and the tube will give you no problems at all! Always fit new O rings on it, top and bottom.