throttle body change

[danutt 4]

how difficult is it to swap a throttle body i gotta 1.8i and wat would be the best throttle body for it and any body done this before maybe have some pics??

is it worth doing this modification? :drunk:

Edited July 31, 2005 by danutt

[Coffee&Doughnut 0]

Well there is a good article concerning this in the latest Total BMW.

Again its the 320i, 325e, and perhaps the 323i that benefit. The 320i was restricted intentionally by the manufacturer, the 318i is probally ok as it is.

Has anyone ported and polished a 320i head with any results to speak of? :puke:

[Gus 5]

its easy, just keep the hoses up so they dont leak coolant (and dont do when hot)

(is there any benefit in disconnecting the hoses that heat the TB??? anyone??)

i just got my bigger one, will post up a review when i get it in

[Coffee&Doughnut 0]

I am waiting for one to arrive bought off e-bay, looking forward to making the change, omeone said with a re-chip it made thier 320i respond very similar to a regular 325i.

[Guest Andrew]

(is there any benefit in disconnecting the hoses that heat the TB??? anyone??)

theres no disadvantages - unless you live in a really cold place.

[mops 4]

Why on earth they would be heating up throttle body and intake mainfold ????

AFAIK, the cooler the intake air the better....

There are many aftermarket mods for other cars to REDUCE the intake air temps, I can not comprehend why BMW would be purposely be heating up their intake mainfolds/throttle bodies ????????

I mean, whats the point of fitting cold air intake, if the air is purposely heated up later down the intake ???????????

can somebody explain ???

[Guest Andrew]

Why on earth they would be heating up throttle body and intake mainfold ????

AFAIK, the cooler the intake air the better....

There are many aftermarket mods for other cars to REDUCE the intake air temps, I can not comprehend why BMW would be purposely be heating up their intake mainfolds/throttle bodies ????????

I mean, whats the point of fitting cold air intake, if the air is purposely heated up later down the intake ???????????

can somebody explain ???

it doesn't heat the air -

it heats the mechanism to stop it from freezing.

[Surge 1]

Im sure it's been asked before, but what's different between the 320i M20 and the 325i M20 (besides displacement) - and is it worthwhile sourcing 325i parts to help the B20 get somewhere in life or is the age old 'drop a b25' again the easier option?

[Carl 3]

The 320 has a smaller intake manifold ports, smaller TB, and smaller exhaust manifold ports, even though everything bolts up the same

The 323 shares the same stuff as the 320

[Coffee&Doughnut 0]

I am soon going to change the throttle body for my 320i, seeing as I will need to grind

some of the some of the intake throttle body port away, Would it be better to just get a

325i intake? And maybe do it in black wrinkle?

[Guest Andrew]

The 320 has a smaller intake manifold ports, smaller TB, and smaller exhaust manifold ports, even though everything bolts up the same

The 323 shares the same stuff as the 320

thats not true -

the 323 head came in 2 port sizes - small and medium-big.

[bumpstop325 0]

i got a 325e TB if anyone wants one.

It can only just fit inside the 325i TB

[Coffee&Doughnut 0]

Sorry guys for bothering you, but before this thread is extinct, just wanted to know if there may be any benefit adding a 325i intake manifold to the 325i tb for the 320i.?

I just have not heard of anyone doing it so dont know if it is worthwhile or not.

[Hartage 0]

Am about to do the change, 325i manifold and throttle body, onto a 323i.

Have already run the T/B on 323i manifold, and that made a difference.

Will post up results when done and run at next intermarque.

[*sic 1]

gettng more breath into the engine and freeing up the exhaust is always going to be benificial. you just need to make sure everything else is up to scratch and it requires what your giving it..

[Coffee&Doughnut 0]

I have been running a chip which has upped the performance somewhat

also K&N panel,and remus exhaust, but it also runs a little rich, so maybe things will balance out a bit with the improved air flow, is that likely?

The car is very well maintained new o2 sensor,plugs, etc I think the cat is shot though so looking at replacing with free-flow type.

It would be good to hear how the 325i manifold goes as you have already trialled the TB.

[Hartage 0]

I Have very free flow Exhaust, 4 cobys 2 in each system ( has 2 completely independant pipes, one for each 3 cylinders ) with no restrictions, its loud. Racing dynamics headers , K&N filter. So have the outward flow as free as possible.

Car is L Jet-tronic so cant put in a chip to improve the performance, but it was dyno run and tuned with advanced timing.

Will re dyno when i have the inlet changed over.

[Coffee&Doughnut 0]

What are Cobys? .. Resonators?

I am trying to decide wether to cut out the cat, retain the twin exhaust and add 18 inch twin resonators, or get a high flow Cat and go 2 into 1 into 2 again at the muffler. Would twin resonators be likely to keep the noise on a similar level as it would be with the stock Cat? thats what I am unsure of. Dont wanna wake up the dead.

[Hartage 0]

I would go with the twin resonators.

Removing the cat will improve the air flow through, as long as you retain a reasonable size rear muffler the noise will not be excessive.

Removing the rear system and putting the open resonators in my car made a huge change to noise! And performance. But this car is mainly a track car.

Keep two systems and avoid joining them up is my advice.

Mine is capable of waking the dead, had to put in the 3rd & 4th resonators to stop car alarms going off while driving slowly through the town!! :pimp:

Edited September 20, 2005 by Hartage

[Coffee&Doughnut 0]

Got the 325i thottle body, I am getting ready to fit it, I have an Air boot that is a 325i one but the aperture for the idle control valve is positioned differently so it may pose a problem. Will keep you posted.

[Hartage 0]

Got the throttle body on and decided to go with the 325i manifold as well.

So have in creased the air flow in, and injector size.

First impressions are that the car has more torque, and is quicker off the mark. Not sure how much quicker, will have the car on the track on sunday at Intermarque.

Will see what the times are like then.

[Carl 3]

Yeah, i've got the 325i T/B aswell, the 320i rubber boot fitted onto the 325i T/B with a little work so no need to get a 325i one.

This is definately a must for 320i owners.

[Guest Andrew]

Got the throttle body on and decided to go with the 325i manifold as well.

So have in creased the air flow in, and injector size.

First impressions are that the car has more torque, and is quicker off the mark. Not sure how much quicker, will have the car on the track on sunday at Intermarque.

Will see what the times are like then.

would like to see a dyno -

will be interesting to see if the ARF and curves are any good.

[Guest Andrew]

Yeah, i've got the 325i T/B aswell, the 320i rubber boot fitted onto the 325i T/B with a little work so no need to get a 325i one.

This is definately a must for 320i owners.

i'm fairly sure the dia. of the AFM is alot smaller also on 320s.

[Carl 3]

Yeah, i've got the 325i T/B aswell, the 320i rubber boot fitted onto the 325i T/B with a little work so no need to get a 325i one.

This is definately a must for 320i owners.

i'm fairly sure the dia. of the AFM is alot smaller also on 320s.

Nope, the AFM's have the same diameter, just the boot on the 320i tapers down to a smaller diameter at the TB whereas the 325i doesn't taper, besides, it's not the AFM that's the bottle neck Edited September 27, 2005 by ///Carl