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PostPosted: December 13, 2016, 7:04 pm 
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Looked but did not find a list of throttle bodies suitable for Independent Runner (IR) F.I. conversions.

I have a set of six Triumph MC bodies that may end up on an Inglese manifold in place of Weber IDA's or PMO's.
Just bought a newer CNC mill so making the adapter plates should be fairly simple.

This got me to wondering what other throttle bodies are commonly used.
Not only bike bodies but also some cars, I think I recall seeing that some BMW cars may be good IR donors?

Wondering if there may be a market for adapter plates.
First need to know which bodies to what manifolds will have the largest untapped market.
Thinking IR bodies to Weber DCOE and IDA intakes to start.

Maybe there are enough of some engines being built to justify adapters to the factory manifold?

Paid too much for this CNC to let it sit idle, so looking for products to make.

Thinking an IR throttle body reference would be useful in any case.
I do not want to develop entire systems, just the adapters.

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Last edited by RichardSIA on January 17, 2017, 7:42 pm, edited 1 time in total.

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PostPosted: December 13, 2016, 8:08 pm 
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Probably the most popular DIY ITB's, at least on small-medium displacement 4cyls, come from the early EFI Suzuki's with the individually cast bodies that can be respaced to match the DCOE manifolds. These come in 3 varities: GSX-R600, GSX-R750/1000, and Hayabusa. So one end would be flanged for a DCOE. The other end could be a simple cylindrical protrusion (maybe with a built in safety bead) to allow a silicone coupling to hold the bodies in place, or the stock boots in the case of the Hayabusa. Alternately for the 600 and 750/1000 bodies, it could be flanged to the bolt pattern and opening shape of the stock boots.

This is something I would certainly be interested in (at the right pri¢e) for the GSX-R750 ITB's I'm using. Otherwise I'm probably going to be making a 3/4" thick plywood spacer that adapts the DCOE bolt pattern and opening to the GSXR boot bolt pattern and opening...By hand.

Newer 4cyl bike bodies are typically cast in pairs, with spacing that doesn't match up with DCOE at all. So a purely machined adapter becomes considerably more complicated and expensive...Although potentially more useful as these older individually cast GSXR bodies become fewer and further between.

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PostPosted: December 14, 2016, 1:15 am 
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Updated!

The Triumph 955 ITB's I have are readily obtainable at this time.
$50.00 - $150.00 per set of three.
They bolt down to the head or manifold so easy to get a solid mount to accommodate the modified linkage.
Future availability is a wild guess.
I see that there are also Triumph ITB's that mount via a rubber boot like the Suzuki parts.
The three in one units are probably useless for most conversions.
This is one of the reasons I do not expect to see cast conversion manifolds being offered, cheaper to just CNC them than to make custom molds for low volume products.

The Suzuki bodies with boots may be a little harder to do than the Triumph version which bolts on, but not too difficult.
Rigid mounting for modified linkage spacing may be an issue.
Guess I need to buy an example to work from.

Checked feeBay, the BMW ITB's are too expensive for Locost builds.

Any other ITB's readily available and popular I may not know about?

What engines would be the biggest users of ITB's without first having a Weber intake?

One possible advantage of MC ITB's is that they are much shorter than a Weber so easier to package in a tight engine bay.
Some users may want a longer intake tract, more aluminum but probably not really any harder to machine.
Biggest ITB disadvantage is the ECM cost unless you can adapt a stock system.

A table of ITB bore size would be useful too.
I know that many ITB's are oval at the head end.

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PostPosted: December 14, 2016, 4:41 am 
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Toyota AE101 ITBs are 42MM and the AE111 are 45MM.

Tried to find good pics of these with poor luck.
From what I can see the throttle bodies only meter air, the injectors fit into the manifold below.
Not a real issue as I am looking at making the adapter, so should be able to make it to accept the injectors.
With 45mm butterfly assemblies available even v8's look possible. :shock:
Prices are a little more than ideal and the injector being separate is a minor bother but I do like the larger bore size.

Anyone have one a pic of these with the throttle body removed from the manifold?

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PostPosted: December 15, 2016, 3:02 pm 
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i have several sets of suzuki throttle bodies that I was going to use on a miata locost but never did. Let me know if this is of interest. I also have two miata intakes that I was going to cut to make the ITB intake manifold.
270 484 0096 tony

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PostPosted: December 15, 2016, 10:32 pm 
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Definitely interested in any and all sample TB's I can get my hands on.
Need samples to make drawings and prototypes from.

Miata and to some extent Honda seem to be about the only non-V8 cars being modified in significant numbers.
What does a Miata manifold look like anyway?
Wondering it an ITB conversion plate could be made for it without welding since I have the CNC mill.

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PostPosted: December 18, 2016, 5:14 pm 
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I've seen 3.5 Chrysler V6 throttle bodies used for a V8 IR system.

They are 47.5mm, and the Intrepids had two- one for each bank of their longitudinal V6.

I have a set to use on my Mercrusier Marine 4.2L (stroked and bored from 3.7) aluminum 4cyl project.


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PostPosted: December 18, 2016, 5:54 pm 
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This is the thread you're looking for:

http://www.msextra.com/forums/viewtopic.php?f=94&t=6602

I have 4 Ducati 748 throttle bodies kicking around that were too wide for my BMW 6.

I ended up going with the S54 BMW factory ITB's from an E46 M3. They're a little large (50mm) but the throttle linkage was SO much easier than adapting bike parts. I need a fairly complex CNC'd adapter to mate them to my later engine, let me know if you want to see drawings, I have a few quotes already but they're all over the map.

Alex.


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PostPosted: December 18, 2016, 7:28 pm 
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Finally have the Fadal VMC in place and running.
Got the com cable run to the PC.

So all I need now is to decide which adapter to make first.

Different TB's have varied advantages in size, price, or construction.
In theory I could just make complete billet TB's but several large companies are already doing that, expensively.
My hope is to tap into the Locost and MS markets for the DIY crowd by supplying only the billet adapter plate.

For the new year I will be obtaining more sample TB's to work with, create a database, and finally make a few first articles.
Nothing to stop me making custom one-off parts but the cost of the CAD and machine time.
But to actually make a few nickles I need to find versions that sell in in the dozens or hundreds.
Not really expecting any of this niche line of product to sell in the thousands. :wink:

So far it seems Weber DCOE, Weber IDA and IDA-3 would be most popular.
I have an Alfa-Romeo SPICA manifold to play with as a start.

Anyone wanting a quote please PM whatever you have for drawings
Any good pics available of TB's are welcome too, measurements are a plus.

If there are other parts needed that are not already being done I am interested in those too. :!:
Plastic and aluminum are preferred material for this machine but steel can be done at a slower pace.

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PostPosted: December 18, 2016, 10:00 pm 
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iadr wrote:
I've seen 3.5 Chrysler V6 throttle bodies used for a V8 IR system.

They are 47.5mm, and the Intrepids had two- one for each bank of their longitudinal V6.

I have a set to use on my Mercrusier Marine 4.2L (stroked and bored from 3.7) aluminum 4cyl project.


Looked them up on feeBay.
Interesting that there are so many variations even for the same company.

These looked most useful, Throttle Body 5283101 For 1993-1994 Intrepid Concorde 3.5L V6 as thy only use two mounting screws and are the most compact.
No injector so they arre really only a bore and throttle blade with a TPS.
Similar to the Toyota bodies.
May be useful but I would have to incorporate the injector boss into the adapter plate.

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PostPosted: December 20, 2016, 7:43 pm 
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HI Richardsia, i had this page salted away it might help
http://www.my-acoustic.com/Car/vacuum/4 ... vacuum.htm


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PostPosted: December 20, 2016, 10:27 pm 
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Put a set of the Triumph triple TB's up against a Weber DCOE manifold tonight.
With a tapered mounting plate they should work great as spacing is nearly perfect.
Just remove one TB and shorten the fuel rail.
Might be a great answer for a lot of the old Brit engines as most of them have Weber DCOE manifolds readily available.

I suppose I will have to complete a conversion to prove it works.
Or make a heck of a deal with someone looking to do their own. :cheers:

Also notice that the BMW TB's make linkage very simple.
They use a single rod along the length of the set with links to each TB.

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PostPosted: December 21, 2016, 4:35 am 
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Made an overlay drawing for Weber 40's and the TR 950 TB's.
A very good fit with no overlapping attachment issues.
Even the linkage between TB's can be left as is, just remove the third TB. :D

Will not be so good for Weber DCOE 45 or IDA replacement.
I will be making more drawings to sort out other possibilities.

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PostPosted: December 24, 2016, 4:47 am 
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A couple of details have become very clear.

Buy carefully!
It seems most of the TB's being offered for sale are missing the TPS, injectors, wire harness, or all of these.
By the time you add them the "Bargain" price is gone.
Seems worthwhile to pay a little more for a complete set, including the wire harness as you will need at least the connector to the TPS.

Same model bike ITB's may be individual or cast in pairs depending on the year.
Newer seem to be mostly cast in pairs, and more expensive.

Honda CBR 1100 Blackbird are cast in pairs, but are also 85mm spread so nearly ideal for DCOE or IDF 90mm replacement.

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PostPosted: January 17, 2017, 8:09 pm 
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Holidays are over at last.
Back on this.
Seems a couple of UK guys stay fairly busy with this sort of work.
With the exchange rate and shipping it should make more sense to make them here.

Looking for sample ITB's and clues for what engines to make the adapters for.
Seems that Miata is a given, what else?

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