E30 Zone

Hey People!

I saw the article in the archive putting an 3.25i throttle body in a 3.20i but it does say what the benefits are of switch throttle bodies??

Can you guys shed some light please??

The 320i TB is a piddling little thing that restricts airflow and thus power.

Fitting the larger 325i TB gives better breathing and a remap to give the extra fuel needed gives a good gain in power and drivability.

Cheers,

Iain T

I have a 325 tb for sale, £20 posted, nice cheap mod....

or better still as in someones sig "Brianmooore once said 'if you're going to fit a 325i throttlebody leave attached to the rest of the engine and fit the whole thing!'

Saved me posting it again!

or better still as in someones sig "Brianmooore once said 'if you're going to fit a 325i throttlebody leave attached to the rest of the engine and fit the whole thing!'

Haha !!! I'll remember that when and if i find out that my piston rings are knackerd!!! Touch wood!!!

Cheers for the offer Munky ... Ive had to spend quite a bit recently on my current idle issues/bodywork so im gona pass for now mate!!

munky30 wrote:I have a 325 tb for sale, £20 posted, nice cheap mod....

will this TB go straight on a 1990 320i? If so...im up for it. Cheers!

has someone actually verified that the gains are real?
I know the answer is probably no because it cost money verifying things on dynos etc.
If people are remapping after adding a bigger TB its probably the remap that gives the gains.

there is a local guy selling BBTB with a chip for m20 engines but likely its the case the chip does a bit but the BBTB does very little. FYI i have tried a BBTB on a stock m20b25 and was disappointed as there was no possitive perceivable change IMHO. The one thing i noticed is it didn't drive as well in topgear at low revs i.e there was a definite torque loss.

I recently fitted a BBTB to my 2.5. Already chipped (Ant) + BTB2 ... was quite impressed with the difference.
Throttle response is much better and the engine seems far more eager.
Pulls far better on the motorway at 3000rpm ... touch the throttle and off she goes.

Definately makes a difference.

G

So if a BBTB is better on a 2.5 .... don't see why a 325 TB on a 320 would not be better. If there was no gain no one would do it.

Islander wrote:

munky30 wrote:I have a 325 tb for sale, £20 posted, nice cheap mod....

will this TB go straight on a 1990 320i? If so...im up for it. Cheers!

as far as I know, yes.

Pm me if you're interested.

It'll go straight on, but will give you an immediate reduction in power because of the sharp edged step between the 325 TB and the 320 manifold's mounting face for the TB.
The 320 manifold has to be opened out to suit the diameter of the 325 TB, which will leave very little gasket area at some points.

"It'll go straight on, but will give you an immediate reduction in power because of the sharp edged step between the 325 TB and the 320 manifold's mounting face for the TB."

Why does that step make such a different Brian? What does it stop? In the pic it only looks about 5mm?

It causes turbulence, spilling off the sharp edge, which effectively reduces the bore of the manifold flange even further.

"It causes turbulence, spilling off the sharp edge, which effectively reduces the bore of the manifold flange even further."

Aha - Cheers O'b'1 - Dont need those kinda issues in my e30 life right now.. got plenty to get on with!!!

so why are the bbtb's for 325's so widely acclaimed by zoners? Surely they would have the same effect?

Brianmoooore wrote:It causes turbulence, spilling off the sharp edge, which effectively reduces the bore of the manifold flange even further.

Best combined with 325 inlet manifold?

best combined with 325 engine.

munky30 wrote:so why are the bbtb's for 325's so widely acclaimed by zoners? Surely they would have the same effect?

very good point with brians comment on the 320 to 325 TB.

does it have the same effect (turbulance)?