intake manifold question

[KakalakiAkka 0]

is obd 2 intake manifold bigger than obd 1? so is it better if i had an obd1 engine with an obd2 manifold?

[Rikki 2]

Cant use obd2 on obd1 and vie versa. Obd1 2.9 is bigger stick with that!

[KakalakiAkka 0]

i know that, but it,s seems similar. just the throttle body is different, or not?

[KakalakiAkka 0]

i'like to customize my intake and if obd2 has better parameters, then we'll cut the stock obd1 manifold. thatswhy i aksed my question, mentioned upper.

[Rikki 2]

If your obd1 get a corrado 2.9 mani it is bigger!

[Dave_ciw 507]

If your going to fabricate, buy yourself a lower intake manifold .......... Then create yourself a nice short runner

[KakalakiAkka 0]

yes i know that a corrado intake will be the best but in our country have very few corrado 2.9 and if anybody has one of it, he won't sell parts from it. so we have to cut. i thought about the short runner but i must try first this. than if it won't be good enough for me, then will come a short runner.

[KakalakiAkka 0]

so, obd 2 is a little bigger than obd 1 or not?

[Rikki 2]

NO........its externally the same size but has a restricted shape on the underside to channel the airflow but they are not interchangable due to a difference in the throttle bodies!!!

[KakalakiAkka 0]

so the difference is just the throttle body? an obd2 manifold with an obd1 throttle body can work, or not?

[KakalakiAkka 0]

i know i have stupid questions, but before we'll cut i'd like to know everything about the differences.

[Rikki 2]

Not. you cant use obd1 with obd2 or obd2 with obd1 without lots of work

[gavinvr6 0]

you will be making a complete waste of time trying to fit an obd1 throttle body onto an ob2 manfold, you will make no gains at all, to save yourself hassle just buy a corrado inlet manifold from ebay.co.uk or any number of vw forums and port polish your original lower manifold, obviously it will cost money but it will be a lot less than realising you have just ruined 2 perfectly good manifolds for nothing then having to go buy another just to get your car on the road again, or if you want to start cutting things up id go with the short runner, it is a complete waste of time trying to do what your talking about,

[KakalakiAkka 0]

okay, thanks the answers.

[KakalakiAkka 0]

i looked both manifold and i see the differences. thank the advices.

[KakalakiAkka 0]

just one more question: luckily i have found a 2.9 manifold. the question is that the 2.8's throttle body is good for it? it's a very important question, please answer it somebody very soon, please!

[supadupagt4 0]

Use the 2.9 throttle body also if you can find one.

bigger is better

[KakalakiAkka 0]

i know it, but i have just a 2.9 manifold without throttle body. so the question is that can use it with my 2.8's trhottle body?

[matty.vrt 120]

2.8 throttle is too small for 2.9 manifold

[KakalakiAkka 0]

ok, thanks for the answers!

[FishWick 21]

OBD1 2.8 and 2.9 throttles are exactly the same size.

OBD2 throttle is slightly smaller diameter and different bolt pattern.

If you want good torque, stick with OBD2

If you want a small top end improvemtn and flat bottom end, go for the 2.9 manifold.

[KakalakiAkka 0]

but it isn't a problem that obd1 has egr and obd 2 hasn't? or you just think on throttle bodies? or throttle+intake?

[FishWick 21]

We don't have EGR in the UK :-)

US and some European OBD2 heads got EGR, which is just a small port on the front which can be plugged

OBD2 = Small throttle + Small intake plenum.

OBD1 2.8 = Big throttle + Small intake plenum

OBD1 2.9 = Big throttle + Bigger intake plenum + higher rev limit.

OBD2 usually always makes the same power as 2.9 with the smaller intake and throttle :-) The smaller throttle and intake keep the gas speed high at low throttle openings, which improves the torque.

[KakalakiAkka 0]

good to you. so i can plug the egr hole. so what do you think: obd1 2,9 intake manifold with 2,9 throttle or obd2 mani with obd1 throttle? or obd 1 2.9 mani with 2,8 throttle?

[KakalakiAkka 0]

i can't decide wich would be thje better. i have the 2.9 mani without 2,9 throttle, but i hav an 2.8 obd2 mani with throtthle, and i have an obd1 2,8. it's a very difficult decision.