Ditching IDAs....

[ecksrash]

So I'm faced with a dilemma.... I have a set of IDAs and they are original Italians. They are old. I just had to tear down my engine and install new rings because of a twisted throttle shaft which washed a cylinder. After all said and done, I'm into the repair over a grand (carbs rebuilt and new cylinders/rings). Now I'm thinking that the money would have been better spent on a REAL tunable FI system with NEW throttle bodies. Are there throttle bodies available that match the IDA pattern? I ask this as I have been giving serious thought to converting another aircooled project that I own to EFI. Thanks Doug S.

[Piledriver]

They exist but they cost more than a set of IDAs...
OTO there is no reason your existing IDAs can't be used as ITBs.

You could even hide some pico injectors & the fuel rails firing down into the throats in the air cleaners... been done.
That's the best setup for high RPM anyway.

[ecksrash]

Oh hell... As far as I'm concerned this set of carbs are beyond economical repair. If I were to do this, I'd pony up for new ITBs. EFF converting these old turds. I'm relay frustrated with these things. I dropped over $800 to have them gone through by Blackline Racing in May and still fighting them to run correctly after they washed a cylinder due to a twisted throttle shaft. I'm pissed that I had to tear an engine down with barely 3000 miles on it. I'm not happy with the thought of dropping more money on a fuel system that is old and no where near as precise as FI. We all know that it's just a guess with carbs and FI will allow more precise tuning with the help of hardware in the FI system. I'm tired of guessing.

[Piledriver]

"Economical?" You said the magic word:
Warning:This site is inhabited by a bunch of old, cheap bastids...

http://www.ebay.com/itm/Yamaha-Waverunn ... 3f&vxp=mtr
http://www.ebay.com/itm/Yamaha-Waverunn ... f7&vxp=mtr
(provided as example, you can get them with their 240cc-300cc pico injectors and TPS for little more sometimes)

These are nice flanged units and only 60mm high,
The FX160 versions are 42mm bore, the "rack" comes apart and you have 4 true itbs.
(I have a good set and a few spares, planning to use them on a 2.5L T4)

These just about will bolt on the huge drag heads like 910s and the DDS head copies out there.(comp eliminators?)

If you are looking for off the shelf/turnkey IDA bolt-ons you are looking at $2500-3K,
Google search shows many, many places that would be delighted to sell them to you at that price.

[ecksrash]

There has to be a source that will be competitive vs. a new set of IDAs. Gene Berg lists TWM throttle bodies in the neighborhood if $560 apiece. I wonder who else out there has IDA pattern throttle bodies.

[Steve Arndt]

Redline has IDA size ITBs. They are very nice quality.

http://s258.photobucket.com/user/Eaallr ... r.jpg.html

[Piledriver]

Extrudabody sells a set of IDA-pattern ITBs for ~1200 http://www.extrudabody.com/servlet/the- ... IDA/Detail

The IDA pattern is ~doubling the price, several places sell modded bike TBs with IDF or DCOE adapters.
Lots of places sell IDF pattern TBs.

Making your own adapters for the bike/jetski ITBs will keep the cost reasonable and the motor will not know the difference.

The Waverunner ITBs can ~bolt on IDF manifolds if you do a tiny bit of welding at the flange on IDF manifolds.
(weld up and redrill a couple existing bolt holes, modding manifolds only)
They can easily be used as two pairs, the spacing is just about perfect for IDFs, so the center balance adjusters still work.

You are not going to find much better quality ITBs than the Keihien or Mikunis.

[ecksrash]

I already have a nice set of match ported IDA manifolds that's why I'd like to stay with that pattern. While we're talking about it... Correct me if I'm wrong, but Megasquirt (or any FI) doesn't care which throttle bodies are used right??? I mean I could homebrew a patched up set of wave runners, or say redline or TWM and get the same results???

[Max Welton]

"The Waverunner ITBs can ~bolt on IDF manifolds if you do a tiny bit of welding at the flange on IDF manifolds."

I'm filing this away ...

Max

[Piledriver]

I already have a nice set of match ported IDA manifolds that's why I'd like to stay with that pattern. While we're talking about it... Correct me if I'm wrong, but Megasquirt (or any FI) doesn't care which throttle bodies are used right??? I mean I could homebrew a patched up set of wave runners, or say redline or TWM and get the same results???

I figured you had welded/match ported manifolds.
The EFI systems and the engine will not know you only spent $80 on your ITBs, and I'll never tell them.
It's all about airflow/injector location etc.
It's important to try to get the matching TPS and connectors etc for the bike/jetski TBs as they are nicely engineered and reliable.
Done with any effort, no duct tape will be required.

There are some excellent examples here and there in this forum.

What's the IDA spacing? (trying to save you making stuff)
There are a couple of bikes that have wide set large bore TBs that might work, Ducati and some Hondas,42-50mm bore range,
Even the Ducati itbs (Weber?) are dirt cheap compared to "afftermarket" TB units, and most bikes die with very low miles.

The 42mm ITBs will probably flow about like your IDAs/42mm vents with decent trumpets added.
There are motorcycle units out to 52mm, but if you want to have it driveable the size should better match the usage.
Some bikes use an ECU controlled stepper motor driven butterfly in the exhaust collector to help keep you on the seat.

Max, you're right, I should really dig out my spare IDF manifolds and weld up the offending (overlapping) stud holes so I can bolt up my Waverunner ITBs this weekend, i have some shortie manifolds for T3 (T4 in a T3) use, should work with tons of room with the 60mm tall TBs..

[Piledriver]

You could also split this set of 48mm IDA pattern TBs with someone
http://www.ebay.com/itm/Weber-Universal ... 1709389551
Jenveys? Smoking deal

Here's a pic looking at a pair of Waverunner 42mm ITBs (160FX) sitting on top of an IDF manifold.
I have them centered, kinda hard to see, but there's a 2-3mm sliver on the inside of each bore that could be cut out of the manifold, or the whole setup could be easily spaced out a few mm w/o even extending the connecting/balance shaft tab.
These are Mikunis, made in Japan.

These are for a Jetski, so the hardware is all SS, and the TBs seems to be anodized or such and clear coated/sealed.

They can bolt together for perfect alignment, an "ear" needs to be welded on the manifold for one of the TBs bolts, and another existing manifold stud hole needs welded up as it overlaps, but we're looking at maybe 5 minutes of work at most for a pair of manifolds.

Ideally, you might want two of the center pairs, as they have the throttle linkage/stops etc all in the middle.
Each TB has a spring and threaded shaft w/flats, one of the set is machined for the TPS.

I got 2 sets for ~$90 (total) a few years ago, w/injectors tps etc off Craigslist from a local boat shop.
The 8 pico injectors alone were probably well worth $90.

I'm using the fuel rails on my T4 with factory manifolds (cut in half with ends TIG'd on). Perfect spacing.

Devastator has a cnc program for pulleys if you simply want to go to a 4-channel split cable pull.
There is a great deal of metal on these tbs that's not needed if used as true itbs.
(There is at least one place in Oz that remachines these a tad and sells them with an adapter plate for DCOEs etc)
Each one has a manifold vacuum port, idle air port, and an air bleed screw.

[Vee Dub Nut]

http://www.thesamba.com/vw/classifieds/ ... id=1700536

[Piledriver]

Not quite sure where to post these as there is another thread on the subject.

These are Yamaha Waverunner 140/160 FX/1100 42mm (true) ITBs mounted on a shorty IDF manifold with a touch of welding to the manifold for the different bolt pattern.

The "snorkels" are allegedly flame arresters but they look more like turbulence eliminators given the fine pitch 1/2" thick SS honeycomb the outer screen bits are made from. (They are the factory "flame arrestor ribbon" cut in half, also very nice velocity stacks)

Note: The easy way to install the stacks is to roll the spring up above the groove: they'll pop right on, then roll the clamp spring back down.
Took a moment of intense cussing to sort that out.

These could easily be split to fit IDA manifolds.
Here, they are at their std spacing.

That is a Synclink drivers side pulley BTW, may use the pulleys and cables and "make" the 2 guide brackets for these ITBs.
(I have no intent to modify any of Slowtwitchs fine work.)

The ITBs come with a pulley setup, but it goes the wrong way for this use, as I wanted the injectors to fire down the port.
Mounted backwards the existing linkage work work, at least for one side. (I have two sets of these)

One downside of these ITBs is the shafts are not threaded on both ends (problem for T1 as the passenger side linkage is in the back)
... although there are several possible ways around that.

IMG_1105.JPG

[Max Welton]

Very clean looking.

Max

[Piledriver]

I should also note that setup significantly clears (1"+ clearance) the engine lid on a Squareback, at least on my mutant installation...

After fiddling with the final details of the linkage bits, as I started with 2 sets, I can modify the Yamaha bits and get a pair of pulleys and idle stops, and fabbing/attaching the cable bracket will be trivial. A WOT stop is kinda inherent in the between TB balance adjustment coupling.

(so I can use the Synclink as intended on the IDFs in the Porsche)

If you weren't possessed to buy two of the setups, Devastators GSXR pulleys will work with only a small amount of TB aluminum grinding in a non critical area, although have him open the thin center part of the pulley as large as safe to allow for the return spring attachment. (you will need to drill a small hole)
You will also have to make some idle stops, but there is no shortage of beefy threaded holes on these things, and the shafts are plenty long to add a thin stop arm or such behind the pulley.

Also: The shafts on the Waverunner TBs have sealed ball bearings on both ends, staked in at 3 spots, but with a light touch of a Dremel tool are removable if you are so possessed.
(perhaps to make sure there are seals on the inside for boost).