ShopTalk Forums | Aircooled VW Tech & Restoration Help

With the EFI now being standard on all RAT engines and now that we have absolutely proven that the TWM throttle bodies absolutely rock it was time to tackle the throttle linkage issues they created.



The TWM throttle bodies locate the butterfly 1" higher than any carb arrangement and with hex bar linkage the down rights would absolutely contact the decklid of a beetle. It was also causing issues with air filters and etc. Going to a bellcrank was the only resolution....... So Brent and I took a couple of days last week to conquer the issue and finish a bellcrank set up that I have been wanting to perfect for a couple of years.


Basically this linkage pictured is modified from some scraps from old Berg linkages, some Helicopter parts and the bellcrank portion of a CSP linkage kit. It requires that the oil cooler housing be lifted 3/4 from the standard position for the throttle cable to pass through the shroud and also requires a bracket to be welded onto the DTM generator stand to hold the bellcrank firmly in place. One piece of the linkage conforms perfectly around the DTM generator stand and makes for VERY easy adjustments.
See how it fits perfectly behind the stand...

Here is the adjustment on the 1-2 cylinder side (That turnbuckle USED to be a chromoly pushrod


Other than that it bolts right on!

Now we just have to make the necessaary mods to clock the bellcrank for carburetors and test that version out and we'll be ready to have the waterjet cutter make the bellcrank pieces and make up kits for this to be sold to existing DTM owners and it will then be standard equipment on all RAT engines. Owners of older DTMs will have to redrill their throttle tube hole, and raise the oil cooler 3/4" and send me their generator stand for our bracket to be welded onto.... Other than that its a breeze and very solidly made.

Here is a pic of the engine that we are using to test it with-t's still on the dyno as we speak and the linkage works GREAT! Of course the production models will look much better than this cobbled up prototype..


Who is interested??? My guess is we can make them from all stainless components for about a 149.00 sale price, maybe less if they sell in bigger volumes. Go here to see a gallery of pics http://www.aircooledtechnology.com/cooking/index.html

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I'll take a set as soon as you give the high sign.

I can yank my alt. stand in about 20 minutes flat - just give the word.

I've been waiting for this since the day you hinted at it.

This may be the ticket to getting my decklid closed (the CB linkage won't allow it).

Dan

Dan,
I knew you'd be up for one!

Keep a watch out here and I'll let you know when we'll have it for sale..

What kind of EFI wiring harness is that? (looking at the injector connectors and lack of strain relief)

The linkage looks sweet.
I have dual ball bearing Power Tuning Parts center pull linkage that makes the CPS linkage look like an erectorset.


Steve

The wire harnass is hard wired into my dyno room for seriously quck and easy EFI start ups...... It was never meant to be installed into a vehicle.

Makes perfect sense. Thanks for the quick reply. EFI rocks.

Nice! Should be more accurate as well I think.

Wouldn't lower intake manifolds be better for this set-up as well?
Would give more room for tall aircleaners also

BTW, what did you come up with for the air filter base, since this will otherwise interfere with the fuel rail ?

Tnx,
Walter

hi jake,
i see that you use vacuum hoses and fittings in the throttle bodies
i suppose there are for the MAP sensor?
i was wondering how i could fit vacuum hoses to my tb's, because i don't have the fittings.
is it also ok to put the fittings in the intake manifolds?
i'm asking this because i'm using megasquirt and want to tune with speed/density..
best regards, peter

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C:\Documents and Settings\piggy\Bureaublad\Eindwerk Megasquirt\foto's motor

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damn, was trying to post a poc but it failed...

peter

Wally,
The shorter intakes atually cause more interferance in a bug because they drop the T/B and air cleaners down in the engine bay increasing the chances of body interferance. I also have more combos designed around the tall manifolds because they have been used on most of my base engines over the years.

The air filter set up is all Billet CNC machined and made just for these T/Bs and my engines... I'll post pics when we have them finished.

Ruff,
Yes the vac hoses are for the MAP readings... You can take your MAP from a tapped hole in the manifold just under the butterfly that leads to a small central plenum to stabilize MAP readings. If your MAP wants to fluctuate and cause uneven idling you can install a Mig welder .030 tip in the hose between the plenum that you make and the map sensor to help stabilize things further... It works wonders-

I'd love a bell crank linkage, I just can't get the CB linkage to work well for me (I'm fine with it on a T1 its just with the bar sitting diagonally I don't get equal throttle openings on both carbs)

Pity that with raising the cooler 3/4" it won't fit in a split bus though..

Paul

How does this setup react to thermal expansion of the engine, effectively making the engine wider and thus pulling the throttle butterflies open when the linkage doesn't expand with the engine as it warms up?

Wow that was a long sentence.

Jan

well for me (I'm fine with it on a T1 its just with the bar sitting diagonally I don't get equal throttle openings on both carbs)

Easy fix for that !
Run up to your local hardware store/Home Depot/Lowes etc. and grab a piece of 1/2 inch flat stock - get your welder out and make a couple of these:




Dan

Thats a good idea Dan, what did you do at the carb throttle end - make up a spacer the side between the throttle bar and the throttle lever?