"the" tall intake manifolds

ArtechnikA · 05-05-2005, 02:18 PM

installing a set of 40mm Webers on an ex-CIS 2,7 -- everybody, including Pelican Wayne's book (p 96), indicate "the" tall manifolds will help -- but i can't seem to find part numbers nor sourcing for "the" tall manifolds.

i'm pretty sure the 901.108.039.04 and 901.108.040.13 that came on my 914.6 aren't them...

thanks in advance...

Porschekid962 · Porschekid962's Garage

The taller the manifold, the farther up in the airstream the tb's move. The farther up they are the less prone they are to intake reversion with lumpy cams. Also you lose some low end throttle response but get a slightly better top end. Most of the MFI setups if not all had the tb's bolted right up to the heads

ArtechnikA · 05-05-2005, 06:33 PM

Quote:

Originally posted by Porschekid962
Most of the MFI setups if not all had the tb's bolted right up to the heads

we'll ignore for the moment the famous RSR 'High-butterfly" throttle bodies and get back to the question i actually asked:

"Where do i get a pair of the "Tall" Weber triple-throat carb manifolds that 'everybody' seems to reference but seem so hard to pin down" ?

al lkosmal · 05-05-2005, 06:51 PM

I believe that PMO offers tall manifolds??

914/6 · 05-05-2005, 09:03 PM

factory tall manifolds 39/46,
you need the PMO's to fit your CIS ports properly

TimT · 05-06-2005, 02:31 PM

PMO makes them in aluminum, the Porsche "tall" manifolds were magnesium, probably can be had at swap meets, and maybe pbase, andial, or some vintage race shops..

ArtechnikA · 05-06-2005, 02:40 PM

i've heard several/many people suggest that PMO has them, but the PMO distributor i've been working with seemed to indicate that they'd never heard of them (i was skeptical, but i want to give him his chance...)

the consensus is also pretty consistent that i need the PMO manifolds to properly seal the CIS groove even though it appears that the intake manifold gasket does that just fine.

i've also been advised against using insulator blocks at the head/manifold interface. how 'bout i run them between the manifold and the carbs? i really don't like the idea of having no insulation between the hot heads and the carbs in these days of volatile pump gas...

so - continuing the topic - has anybody actually seen the PMO velocity stacks? they look shiney metal in the carb photos but my guy told me they had only plastic (?)...

thanks for the input, everyone !

914/6 · 05-06-2005, 03:13 PM

The Gasket covers the CIS injector notch. The manifold goes right to the edge,Does not cover it. You're Call
Here are the manifolds 1. PMO tall, 2. PMO CIS about .75 taller than stock 3.Stock 4. R tall mag.
I would only buy the steel stacks, I have seen alot of melted plastic ones.
I thought PMO only used the steel ones?

ArtechnikA · 05-06-2005, 03:42 PM

Quote:

Originally posted by 914/6
The Gasket covers the CIS injector notch. The manifold goes right to the edge,Does not cover it.

I thought PMO only used the steel ones?

cool - you have them all there to compare... i've got a 2,7S with the 35mm intake ports. of the "PMO Tall" and the "PMO CIS" which is going to be the better match for those? do you have diameters for the bottom of the manifolds?

i have the stock stacks from the Webers, but there is a bit of surface rust, so i'm trading off a prep/refinish cycle against $90... if the PMO's are nice, metal, full-radius, all that, i might just spring for it. i do wish there were better illustrations of the products somewhere. i don't mind spending the money where there is value but i do like to know what i'm getting...

TimT · 05-06-2005, 03:47 PM

Use the insulator blocks between the head and manifold. I have run a Weber carbed 911 like this for years.. also the dia of the manifold is different top and bottom.. the insulators only fit on the bottom... unless you have some special one off insulators.

Also have had plastic and metal stacks.. either work, prefer metal..( broke a plastic stack once)

Skip your PMO dist and call PMO direct. they have tall manifolds, I currently have a set on each of my cars.

Oops if the host is your PMO dist tell them that PMO does in fact sell tall manifolds.

Steve@Rennsport · 05-06-2005, 11:52 PM

LOL,...I am a PMO distributor and tall manifolds are ALL we sell & use.

One must use the insulators between the heads and manifolds to deal with the volatility of pump gasolines and their propensity to boil over on heat soak.

Like TimT, I've been driving a carbureted 911 for 25+ years and if they are installed and setup properly, its as bulletproof an induction as there is,.....

joetiii · joetiii's Garage

Whats the difference in height beteen Tall manifolds, and regular PMO manifolds?

Quote:

Originally Posted by 914/6

The Gasket covers the CIS injector notch. The manifold goes right to the edge,Does not cover it. You're Call
Here are the manifolds 1. PMO tall, 2. PMO CIS about .75 taller than stock 3.Stock 4. R tall mag.
I would only buy the steel stacks, I have seen alot of melted plastic ones.
I thought PMO only used the steel ones?

ArtechnikA · 07-13-2009, 04:12 AM

amazing how much some things change, while others stay the same ...

I had completely forgotten about this thread!

Since my original inquiry in 2005 I've given up on the whole concept of trying to run Weber 40's on the 2,7 - since I sold them along with the car they came on. I have a pair of 46's as a 'contingency plan' but the real current plan is to build up a 2,8RSR-esque engine and use MFI.

I still have the PMO manifold set - somewhere. The 46's came with manifolds (nice tall ones) so I'm covered there. I have no idea what manifolds I'll run with the MFI but of course I lust after the Eurometrix setup.

And the engine still isn't together and therefore the car still isn't running... Maybe this winter...

JGalt · 07-14-2009, 12:22 PM

My recollection is the the 911R / 906 manifolds were magnesium, not steel.

ArtechnikA · 07-14-2009, 12:51 PM

Quote:

Originally Posted by JGalt

My recollection is the the 911R / 906 manifolds were magnesium, not steel.

Where did you see that anyone suggested any manifolds were steel?
I've never seen a ferrous 911 intake manifold, but I don't claim to have seen them all. But I can't imagine why there'd ever be one.

The only reference to R/906 manifolds in this thread was the caption to the photograph that referred to them as magnesium.

(There was a reference to steel velocity stacks, as opposed to the sometimes-plastic factory versions...)

JGalt · 07-15-2009, 04:53 AM

You are correct. I skimmed through the postings too quickly and wasn't playing close attention when the comments referred to "stacks".

ArtechnikA · 07-15-2009, 05:43 AM

Quote:

Originally Posted by JGalt

You are correct. I skimmed through the postings too quickly and wasn't playing close attention when the comments referred to "stacks".

I apologize for the snippy tone of my reply.

What can I say - my head was in a different place and I shouldn't have sent it at all.

ChicagoPete · 07-15-2009, 07:40 AM

Quote:

Originally Posted by JGalt

My recollection is the the 911R / 906 manifolds were magnesium, not steel.

The factory ones are only made from magnesium and have the part # stamped on them.

If they don't have a part # stamped on them they are most likely repros done in aluminum. Carl Thompson had a run of repros done a long time ago and there are some of those floating around.

Real factory mag 911R intakes are going for around $2000-$2500/pair.

If you are looking for that factory look versus the PMO tall look there's a guy in France making aluminum reproductions. His user name on early911SRegistry is OliveR.

He also has a website.

http://www.sgracingclassic.be/store/product_info.php?cPath=34&products_id=86&osCsid=6abeb5cdc892905d2ab9b2830618e08d

I hope the link works...I believe the price listed there is for each, so 1400Euro for the pair.

Peter