VFR 800 TBI linkage?

[alec50761]

Hi,

Just wondering if anyone had used vfr 800 and had any pictures of how they set up their linkages? I'm getting a little lost trying to figure out how to set it up.

oh and this is on a t1 engine in a beetle if that helps and I'm using metal adapters TIGed onto the ITBs that will bolt straight onto a set of del manifolds.

cheers
Alec

[aircooledtechguy]

I'm planning to use the same ITBs on my Squareback with my new motor. However it's not built yet, so I don't have any advice at this point.

They must move in the same direction, so a similar, albeit better arrangement than Kadrons would probably be on the menu. I would personally like to be able to keep it cable driven. . . I'll worry about that when I get closer.

Post up whatever you come up with. . .

[Piledriver]

Bolt `em on and post some good pics, preferably showing the existing pulleys/linkage on the TBs.

There are quite a few devious minds here, someone will probably have an "Aha!" moment.

(remember--- pulleys can pull from the top or the bottom...or one of each to provide the same or mirrored motion.)

[Slamd72btl]

I plan on seeing if CSP IDF bellcrank linkage will work since I already have it, but I don't have the TBs yet - hopefully in about a week. Looks like it should work though. Cable linkage would be nice though if you have the resources or ingenuity

[alec50761]

cheers for the responses.

thanks piledriver but sadly i can't really put them on the engine yet as i haven't made up the adapter plates, and the cars a daily driver so want it off the road for the minimum time possible. I'll see if i can mock them up on the manifolds so people can see the issue.

in response to the other posts heres the problems i see with different approaches:

-there are a few problems i can see with 'normal' twin carb linkages;
1) the leftpairs throttle shaft doesn't run all the way through, it stops in a bearing in the tb, this would mean you'd have to mount any linkage arm or wheel on the opposite side. this then doesn't match the other side as the tps sensor is on that end.
2) if i flipped the tbs round so both ends with linkage arms lined up and used a kadron style linkage the fuel rails would be on the same side and one would probably foul the fan shroud.

also in case anyone isn't used to the vfr tbs, only one pair has a wheel, then the original linkage between the pairs is mounted between the barrels, right where the fanshroud is. so that can't be used to link them.

I was thinking of trying to spin one throttle shaft around so that the free ends lined up, but the screws on the butterflys have seized??!!!!

I have also thought about running a 2 cable linkage to the drop arms between the barrels on the pairs and using the manifolds bolts to support the bracket for it, or buying another pair of tbs and use the same sides from both pairs, enabling me to take the tps of one and have a normal style linkage if that makes any sense?

cheers
Alec

[alec50761]

i think i'm going to get the newer vtec style itbs as they appear to use throttle shafts that run the full length of the tbs. This should let me fix a wheel onto the shaft without one and run a dual cable system, or just use a normal linkage with arms on the shafts. Will put up pictures when i've figured it out.

[alec50761]

once again a change of plan. I've managed to remove the butterflys on half the itbs. Then swapped shaft around. Need to get some new screws for the butterflyes but then going to but 'normal' ball joints on the ends to use a type 3 linkage (only as its cheaper than CB or scats versions and i'm on a budget). Should also have the manifold adapter plates and plenums done in a couple of weeks time, picking up the metal on Tuesday will post pics when its all attached to manifolds etc.

[Max Welton]

I am watching this thread with interest. I have the same ITBs but picked up two sets in order to be able to use a cable-pull on both sides. My machinist is modifying some IDF manifolds to accept the ITBs. I'll put up some pictures when I have them back. There are companies selling all sorts of control-cable hardware I should be able to make the linkage with.

Max

[alec50761]

Hi Max,

I was thinking of using a cable pull system, but found that it probably made the process a little harder for me. And as i have the linkage parts why not use them. Should look sweet when you've done it!

Out of interest, are you machining the actual manifolds and then welding the itbs into them? Is there any advantage to that over using adapter plates?

Alec

[Max Welton]

We're building up the inside of the manifold at the flange then recutting the hole to form a spigot for the TB. We'll put an o-ring in the groove that is already around the OD of the TB to form the seal. The whole deal winds up shorter ... important in a Ghia engine bay.

Max

[alec50761]

Ah makes sense, guess the heights the major factor. Mines in a beetle so don't have to worry, and I'm only using a 10mm bit of ali plate to make the adapter. Think my turbo hats may require a bit of decklid trimming or standoffs though.

As an update, I've got all the metal today, just need to finish exams and then on with fabrication!

Alec

[Max Welton]

I noticed something about the Honda setup. The FPR is plumbed into what appears to be manifold vacuum. I think they are moderating injector flow by making fuel pressure a function of manifold vacuum. Is it possible their ECU applies a fixed pulse width and fuel is controlled only by MAP and RPM? Interesting.

Max

[Steve Arndt]

99% of vehicles with EFI have vacuum referenced FPR Max. What is different about the Honda setup?

[Max Welton]

I did not know that Steve. Just learning about FI.

What I'll have to do is have these injectors flow-tested at several PSIs and also see what the FPR does at different MAP values. This is cool!

Apologies for the hijack Alec. Back to you.

Max

[Piledriver]

Not running the referenced FPR can make it a lot easier to tune accels etc NA, but won't work well with "large" for the engine injectors (or possibly ancient//slow injectors), the pressure cut at idle particularly helps.

I should probably hook my vac reference back up now that I know what all the knobs do...