throttle body manifolds?

[crashmy911]

I've got a set of 48mm throttle bodies from tmw. I need the manifolds to connect to my three liter . Do they come in differen't sizes? Do I need a specific size to work better or worse? Can i pick up set of any carb manifolds and make them work? Thanks Jim

[Steve@Rennsport]

Jim,

You can use any carbureted manifold as long as it matches your heads and your TWM throttles.

[crashmy911]

Steve I'm new to this stuff what do I need? thanks

[Steve@Rennsport]

3.0 motors came with two intake port sizes: 39mm for the '78-'79 engines and 34mm for the '80-'83 engines.

You'll then need to measure the ID of your TWM throttles right at their base.

Once you know these two critical bits of info, you can get a pair of manifolds that will work.

Personally, I'd use the tall, PMO ones.

[jpnovak]

Which TWM ITBs do you have? Personally I think 48mm is a bit large for a 3.0 unless it is all out race spec.

If you have the TWM 3003 series you need the standard linkage and manifolds from weber or Zenith carbs. PMO manifolds are another option.

Make sure you get the L and R manifolds as the L version has a stud and bell crank to connect the throttle linkage coming off the transmission. You will likely want the early style bell crank on the transmission although not completely necessary. The early style has a different arm length and relative arm angle to fit the carbs/ITB geometry compared with the CIS mounting plate geometry. If you use the CIS style bell crank on the tranny your mid-throttle modulation may suffer. This problem will be magnified with the high swept area of the 48mm ITBs.

For the linkage make sure you obtain the two drop links, the cross bar, the cross bar supports (L&R), the longitudinal connection and the manifold bell crank. There is also a different length throttle rod that connects the bell crank on the manifold to the bell crank on the transmission.

When you get the manifolds you can simply port them to a size that matches your heads. Depending on your year 3.0 this could be 34 or 39mm. The top side would match the lower ID of the TWMs.

Enjoy the switch to EFI. Its worth it!

[crashmy911]

They are early 1978sc heads. I'm going to run high compression and ge60 cams. Will the 48mm throttle bodies still be a problem? This will be on a track and autocross car. No street driving. Also if I go with s 911s cam could I just get a regrind instead of buying brand new cam shafts?

[crashmy911]

tall pmo they will be!!!!!!

[brads911sc]

talk to john at daugherty cams on your cams...

[haycait911]

Originally Posted by brads911sc

talk to john at daugherty cams on your cams...

amazing service..............

Pelican Parts Technical BBS - View Profile: camgrinder

http://drcamshafts.com/

[martin.maurice]

In the shop where I work we use MOC Throttle Plate Cleaner and MOC Top Engine Cleaner. Brake cleaner is a little weak for this work.

Since you have already removed the manifolds and throttle body, you can spray throttle plate cleaner several times and use rags to clean them until you see the metal.