Are 2.8 and 2.9 throttle bodies different?

Or not? If they are different whats the difference and is it worth doing work to one for a performance gain?

 

i think 0bd1 2.9 tb's are different they have no bump at the bottom and i've got a feeling they might be slightly bigger

 

2.9 obd1 throttle bodies are larger than 2.8 and obd2 are the same,but obd2 only came out in 2.8 form in th UK.

as for performance gains......dont know,but i think the obd1 are better for torque.

 

So would it be worth 80 to swap my 2.8 inlet manifold and TB for 2.9 ones?

 

yer its worth it as the inlet manifold is alot bigger on the 2.9 it goes all the way to the outside rather than the 2.8 thats pretty much just the middle

 

I just bought a 2.8 one for 1.04p. I'll see if I can do anything with it.

 

you can have the "ramp" welded up and ground out on a 2.8 one.

the mechanism differs slightly on the 2. the 2.8 one has a linear movement, the other is sort of staged, so it moves the butterfly at different speeds depending on the position. some people don't like the way the car feels with the 2.9 body on it and prefer a modified 2.8 one.

 

Cool!! How much do you reckon to have it modified properly?

Also I have a few 2.8 inlet manifolds. Could I cut the bottom off one and open it up to be like a 2.9one?

Is it better because it can hold more air, supply and demand and all that?

 

both can be done, find a friendly (i.e., cheap) alloy welding service.

 

I'll get chopping on the manifold. I'll post up pics when I start.

I've got a sapre air box, manifold and TB now to play with.

What about the ribbed rubber elbow? Load of crap or what?

 

I've got the throttle body and its now in the dishwasher

Ebay pic:

 

When you shave the humps out of the 2.8 obd1 t.b it makes the car much more responsive low down, as the butterly allows more air pass. Charistics of the 2.9 t.b.
Makes a big difference. The 2.9 inlet mainfold holds more air, i think improved top end, more low down torque from 2.8 inlet i found.
2.9 is better for forced induction.
You can do the t.b yourself with a decent drill and a grind stone attachment...take your time as i know someone who grinded to the point the drill came out the side of the t.b

 

DOH!!! I'll try and be a bit more careful!!

I'll stick my drill in the van and have a go while i'm not busy. I thought of cutting off the 'hump' that helps hold the jubilee clip then go back from there. Is that called Bell Mouthing?

Heres the manifold after I dropped the stihl saw on it

 

Just removed my throttle body and inlet manifold today, so what exactley have you done to yours and noticed any difference? Really want to try shaving this 'hump off' but without being dumb where is it that you shave it off?

 

I've not finished doing it yet. You can just about see the hump in the top part of it on the e-bay pic. I've got a thing for a drill now so it should be miles faster than the dremmel.

I've also cut off the coolant pipe connections which should keep it cooler, aparently.

The bit that i've shaved off so far shows how more air goes through it when its just slightly open. I did half of the hump at first and when I opened it you could see the difference.

 

Cheers - since reading your threads i've decided to check my wiring and took the throttle bodies and inlet manifold off today. Might buy a spare throttle body first before attempting this

 

I'm also thinking of replacing the rubber with plastic because its so smoth on the inside, would it take the heat?

 

Taken my TB off and seen the hump; anyone know whats the best drill bit to use and can point me to any examples?

Cheers

 

Just awaiting my 2.9 inlet manifold and the difference appears to be amazing; all in all 50 for the inlet manifold to my door.

Hopefully will gently grind the ramp off and see how it feels

Great thread as without it i probably would have never done this

 

2.9 inlet arrived today; for reference here's my new 2.9 inlet against my current 2.8 one (also got a nice miltek decat above )