450 R/T intake manifold questions/comments

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wcorey
Posts: 323
Joined: Sun Jan 31, 2010 1:50 am
Location: MA USA

450 R/T intake manifold questions/comments

Postby wcorey » Wed Feb 10, 2010 4:08 am

As suggested I moved this and some porting questions from the wiring harness thread to their own threads...

New here, doing a 450 R/T project.

What is up with the intake manifold on the R/T? The port on the head has a nice straight shot to the valve (unlike some of the later pantah derived twins) but the manifold looks like two straight pieces of tubing cut at an angle and stuck together rather than a nice linear bend that would be conducive to flow. I'm sure it was orientated to level the carb and place the carb and air cleaner away from other obstructions but it seems like there would have been a more efficient way to do it. Looks like when they made the original for molding they just took a pie slice out of a straight one and welded it back together at the desired angle. The more I look at it I think the cut and weld method might be how every one was made.

I will most likely re-carb anyway (another bunch of ?'s there) so it obviously has to go, can't see leaving that afterthought looking thing in there anyway.
I know from experience with the mid '90's 900ss motors that a longer manifold gets more midrange and shorter gets more top end but those also have longer, bent, poorly shaped intake ports to begin with and all that may not directly apply here.

Obviously if I put in a bigger carb I'll taper/blend the manifold to the head and may have some limitations on placement around other things. I've noticed a multitude of variation in how aftermarket/homemade manifolds are setup on other Ducati singles, long, short, bent, straight. Is there a 'right' way as far as performance and most 'other' ways are due to fitment issues and/or cosmetics? As it relates to performance, do other models have different requirements?

I'm about to start another thread addressing porting, which will most likely tie in closely here and influence the direction I need to take.

Image

FYI There are also additional details and pics on my posts in the wiring harness thread.

Teckhardt
Posts: 394
Joined: Sat Oct 31, 2009 10:25 pm
Location: Pacifc Northwet USA

Re: 450 R/T intake manifold questions/comments

Postby Teckhardt » Wed Feb 10, 2010 5:27 am

wcorey wrote: I will most likely re-carb anyway


What are you thinking of going with???
1970 450 SCR

wcorey
Posts: 323
Joined: Sun Jan 31, 2010 1:50 am
Location: MA USA

Re: 450 R/T intake manifold questions/comments

Postby wcorey » Wed Feb 10, 2010 6:48 am

What are you thinking of going with???


I have a large box of multiple options, 40mm Dellorto (phf?), typical Mikuni roundslides in 31, 32 or 34mm, Mikuni flatslides in 36 or 40mm, Amal concentrics...
I'm leaning toward the mikuni tm36, the 40mm stuff seems like a lot of carb if I'm not camming, don't want to compromise my midrange too much either. If I had one I'd do a Keihin fcr, I really like 'em and the angled float bowl would allow for a nice straight manifold. Big bucks for a new one though...
I was going to ask the carb question on a separate thread and hope to get some direction. Easy enough to swap carbs around though, as long as I don't open up the port too much, so eventually may try a few.


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