J Series Individual Throttle Bodies - ITB's

[IDon'tKnow]

Hopefully this thread will become a place where everyone out there hoping to, or in the process of, fabricate themselves a set of ITB's can compare notes and exchange ideas.

Let's face it - ITB's aren't in the works from any manufacturer and they won't be until there are much more off the shelf tuning parts for the J (Pistons, Valvetrain, Rods, Cams, Ect...) out in the marketplace. Until then they figure there isn't much need for them / market for them and they are right at least on the former point.

Anyway; I'm in the process of fabricating a set for my build and I've been documenting it in my Build Thread (http://www.j32a.com/showthread.php?t=357). I figured the project deserves some exposure outside of "The Crazy Guy Putting a J in an MR2" Realm, so here it is.

I'm just cutting and pasting the first few posts about them below and adding more info as I get it. Thanks for looking guys, ideas are definitely welcome, and Enjoy:

[IDon'tKnow]

The silver and blacktop 4AGE itb's tend to be a little bit more expensive and harder to come by. They do have the three point flanges on them that would perhaps make bolting them up to the motor a bit easier. I'm not sure about how easy it is to adjust their horizontal spacing.

I think I'm going to stick with the Hyabusa TB's though. They're larger (granted only by 1mm) and they are all over the place.

The plan is to take the original injector bases and take about half of the length out of the runners.

Originally like this:
http://lh5.ggpht.com/_Zxi5uBiDYZQ/S6MBbvGnLbI/AAAAAAAAJkM/r6jrQBA_3Rc/InjectorBase.jpg

Cut down to this:
http://lh6.ggpht.com/_Zxi5uBiDYZQ/S6MBcBiGg2I/AAAAAAAAJkU/bgFEmM_gsz0/InjectorBase2.JPG

In order to allow the tb's to be mounted to something like this:
http://lh5.ggpht.com/_Zxi5uBiDYZQ/S6MBcfdc6wI/AAAAAAAAJkc/S23obz6eKNU/InjectorBase3.JPG

I'm not exactly sure how I will go about attaching the the TB's to the runners. I can either tig flanges onto the tb's or I can just match the TB to the runner and use a silicone coupler. The advantage of using the coupler will be that I can experiment with different length runners with minimal effort; i.e. I won't need to have flanges on both sides of the secondary part of the runners which will mean that only half the welding will be needed to test different lengths.

[IDon'tKnow]

These are just tacked together for test fitting on the motor. They still need a solid bead and some fill before I can get them cleaned up and ready. In neither of the pictures are the injector bases pushed all the way down on the dowels so they aren't aligned perfectly.
http://lh5.ggpht.com/_Zxi5uBiDYZQ/S6usbRR4UOI/AAAAAAAAKwg/ivsJgodLVQ8/s912/DSC_0376.JPG
http://lh6.ggpht.com/_Zxi5uBiDYZQ/S6usbt18OdI/AAAAAAAAKwo/KeeD9M2BHhA/s640/DSC_0377.JPG
You can see there is an alignment issue that needs to be sorted out. I'm going to cut the tacks off and move them both up and in the opposite direction of each other. In addition to that I am going to have to slant the runners on the TB mount just a degree or two for clearance:
http://lh5.ggpht.com/_Zxi5uBiDYZQ/S6usy7XWYRI/AAAAAAAAKww/opfdY53NygU/s640/DSC_0378.JPG
You can see here where it needs that 1-2* of tilt for the runners to clear. You can also see how the oblong shape of the runner at the base doesn't align with the circular portion. Those areas are going to have fill welds on the back side of the thin areas and then be hand blended.
http://lh3.ggpht.com/_Zxi5uBiDYZQ/S6uszAgvdaI/AAAAAAAAKw4/nIUj7xStMpI/s912/DSC_0380.JPG
6061 Stock I am going to cut flanges out of:
http://lh5.ggpht.com/_Zxi5uBiDYZQ/S6uszdx47oI/AAAAAAAAKxA/i-oQuSk0BF0/s912/DSC_0384.JPG

[IDon'tKnow]

My first set of Hyabusa ITB's came in today.
http://lh3.ggpht.com/_Zxi5uBiDYZQ/S7FCYdLYyGI/AAAAAAAALBM/8AP-ZQTOI9Y/s800/DSC_0386.JPG
Now that I have them in hand I realize that I am going to have to change the design. If I went forward with the design I was working on I would end up placing the runner for the opposing bank directly over the injector for the other. Of course that's not a good thing.
http://lh5.ggpht.com/_Zxi5uBiDYZQ/S7FCacKmVaI/AAAAAAAALBU/4xodrJTaCZc/s800/DSC_0387.JPG
So I have two options - Chop up the TB's (which is going to have to happen either way) and mount them the the original injector bases or cut a flange, weld the TB's into it and mount them directly to the cylinder head.
http://lh5.ggpht.com/_Zxi5uBiDYZQ/S7FCnn9N6PI/AAAAAAAALBg/ehaEPNodyZg/s912/DSC_0388.JPG
I'm leaning toward the latter option. You can't see it in the pictures I have here but on the underside of the ITB setup the runners have the injector mounts cast into them so that would need to be addressed if I were going to mount them to the injector bases which are totally round. On top of that the first option would end up giving me a runner which was nearly identical in length to the OEM intake manifold, and it would give me the taper of the TB (goes from like 46mm to 41mm) way too early on the runner; I would end up with a 6 inch low pressure zone between the throttle butterfly and the intake valves. On the other hand, with the latter option, the taper would take place just an inch or two from the inlet valves; increasing the velocity of the incoming air with almost no "low pressure area" in front of it.

In order to make them clear the opposing bank I would need to cut the TB's down and inch on the inlet side and then get some custom "press-in" velocity stacks with a slight mandrel bend in them.

Any input guys?

[IDon'tKnow]

This new plan is coming along nicely. I went ahead and did some measuring that clarifies for me how these will act on the motor.

47.35mm Butterfly
49.76mm Inlet
41.91mm Outlet (Should provide a nice venturi effect since the taper is so close the the valves*)

When trimmed down (the way they will need to be in order to clear each other inside the V of a 60* V6 - 1" on one side and 1/8" on the other) to minimum height:
56.13mm Height
*~120.65mm Distance from valve to butterfly


The flange isn't quite right but it's 0.1 and I like it.
http://lh3.ggpht.com/_Zxi5uBiDYZQ/S7YQyyFxmrI/AAAAAAAALcw/yZivlY12HhU/s912/DSC_0452.JPG

Basic idea of how they will fit: http://lh3.ggpht.com/_Zxi5uBiDYZQ/S7YQ0Uk7fkI/AAAAAAAALc4/-C8V8WN2LEM/s912/DSC_0453.JPG

The TB will be ground down to essentially just barrels. They'll be welded into one solid unit so they won't need their rod assembly parts. Little tabs will need to be tacked onto the lever mechanisms since they are being spaced out a couple cm.

http://lh3.ggpht.com/_Zxi5uBiDYZQ/S7YQ1c9_-8I/AAAAAAAALdA/6m0UTDcQ7lc/s1280/DSC_0454.JPG


http://lh4.ggpht.com/_Zxi5uBiDYZQ/S7YRFdg8P6I/AAAAAAAALdI/ggb39Lm3NCU/s1280/DSC_0455.JPG

Of course I will port match this to the head. Also, the TB is sitting inside of and inset that will not be there on the final design.
These are nicely on center and the studs line up well.

http://lh6.ggpht.com/_Zxi5uBiDYZQ/S7YRH4aA4GI/AAAAAAAALdY/UxQcNCFTkdo/s1152/DSC_0458.JPG

I bought myself a cool little tool called a Foredom Flex Shaft Grinder. It will come in handy when it's time to port match this.

http://lh5.ggpht.com/_Zxi5uBiDYZQ/S7YRJZe9bJI/AAAAAAAALdk/OUwNPvKJhVU/s640/DSC_0460.JPG

[chanster781]

J32 ITB hell to the YEAHHH cant wait to see the finishing product. keep up the good work-

[hondaboy4life]

So, you're having close to zero runner length?

check this out as well has a few helpful bits of info.

http://www.jenvey.co.uk/Index.htm (click on FAQ)

[IDon'tKnow]

Ben, After you mentioned in my other thread that your plan was to go with the Jenvey TB's I went through and read all of the technical information I could find on their site.

"Induction length is one of the most important aspects of fuelling performance engines.
In our experience an under-length system is the greatest cause of disapointment, with loss of up to 1/3 of power potential. There are a number of good books on the subject and the serious developer is referred to these and, in particular, dyno trials. A guide figure, from the face of the trumpet to the centre of the valve head is 350mm for a 9,000 RPM engine. Other RPM are proportional, i.e. for 18,000 RPM the figure is ca 175mm. "
I'm not trying to run an incredibly short system, I'm just mounting the TB very close to the head and will run a long trumpet.
Jenvey has a few things to say about butterfly location: "The butterfly is an important aid to fuel mixing. When positioned too close to the valve this advantage will be lost whilst positioning far away may lead to a loss of response.
As with the injector position (see below), higher RPM demands a larger butterfly to valve distance. A practical minimum figure for a 7 - 9,000 RPM engine is 200mm, whilst the maximum is dictated by the need to fit an air horn of reasonable length to achieve a good overall tract shape."

Although the butterfly placement won't be perfectly ideal, the response should be excellent and I will get the benefit of having (nearly) straight ports, whereas other designs dictate that they have a fairly steep bend in them for clearance on the 60* V6. I also understand that it's less than ideal for that bend to be in opposing directions; s-bend.

I would like to be able to experiment with the runner length and shape but I'm afraid that buying multiple custom velocity stacks will be cost prohibitive.

[twistedimage]

wow good deal of work cant wait to see this done

[hondaboy4life]

There's also some good info/links in this thread...

http://www.eng-tips.com/viewthread.cfm?qid=165529&page=1

[IDon'tKnow]

It seems that you and I spend our time reading the same material. I love the eng-tips forum.

[DOWN_SINCE_DAY_1]

thats great an ready to see numbers

[hondaboy4life]

It seems that you and I spend our time reading the same material. I love the eng-tips forum.

You an engineer? I'm currently a rising mech. engr. can't wait to take the elective powerplants courses under David George (previously was the lead engineer for roush yates engines). Should hopefully have a good grasp on anything engine related after those classes.

[IDon'tKnow]

I'd like to think I am but I'm not. If all goes according to plan I will be enrolled in the Mech Eng program at UAH this fall. UAH is a fantastic engineering school. The Eng-Tips forum is just where I've ended up over and over again in my search for information. When you've been a keyboard jockey/tuner for as long as I have you're bound to end up there; it's where all of the small-time-tuner-bs and snake-oil tuning get's put in it's proper place.

[Pinho]

Looking good!!!!!!!!!

[starboy869]

good work

[Pinho]

update?

[wolydotmatrix]

update?

x2

[IDon'tKnow]

x2

I bought the second set of Hayabusa ITB's a couple weeks ago and they are sitting out in my workshop. I just got finished moving my family into a new house just a couple days ago (still settling in) and it's been fairly smooth but time consuming. Anyway, instead of housing my project in an 8x10 shed I now have a 25x15 workshop to stretch out in.

There are some clearance issues with getting the TIG welder between the flange we cut and the ridges that sit next to the injector holes on the TB's. The TB's are getting hacked to pieces anyway so it isn't a big deal it just needs to be ground down.

I sat down with a cutting wheel and some grinding burs and got one of the TB's ready for the machine shop to work on but still have five to go. I'll work on them some later this week.

The first time I sat down to use the Foredom grinder I was loving it but I managed to bust the flex shaft on it within an hour. I ordered a longer heavier duty shaft and when it came in I realized that is used a different drive pattern than the hand piece I had bought so I had to get a different hand piece. Long story short I now have close to $500 tied up in my grinder. I don't mind though - it's going to come in very handy in the next couple months. Just for comparison - I was using a Mac-Tools die grinder on a 150 Gallon air compressor before I bought the Foredom grinder, and this things gets the same job done in half the time.

[IDon'tKnow]

To use this design I will have to buy uprated Hayabusa injectors ($450), get my hands on some funky custom velocity stacks ($300 at least), as well as a few other things.

I'm backseating this project temporarily so I can focus more on getting my JW11 up and running first. When I get working again on the ITB's - which I will, I have half of the materials I need - I will be going back to the simplest route; simply making the TB's mount to the OEM injector bases. That way I won't have to toy with the injectors or fuel rail location. Also, by chopping out the bottom side of the TB where the injector mounts, I will be able to eliminate the majority of the taper which I was concerned was too severe for a 3.5 liter motor.

Maybe I will get this done and ready to test when I initially tune the JW11, maybe not. Either way, they will be up and running eventually.

[Noir]

Nice work so far. I can't wait to see these finished.

[mrphrancis013]

Not to bring up an old thread or beat a dead horse. I was wondering how these are coming along? I am thinking of doing some ITB's myself. I was aiming at using some Daytona 675. Inline 3, 44mm, 675cc (or so I have read) injectors, and pretty cheap at cost. Nice little setup. Although using hayabusa's ITB's welded to a plenum could work very well for a custom boosted application, but that's not for this thread section. I hear a lot of people switching out the busa's injectors for s2000 injectors.

[gfrg88]

I believe he just scrapped the project..

[mrphrancis013]

Ah, well that is a real shame. You could make some real power with these motors. I keep picturing it sounding like an NSX with ITB's. Maybe when I take up the project, I can revive this thread for the hopefuls.

[IDon'tKnow]

Yeah, my ITB dreams have been dashed. I wouldn't start with the Hayabusa TB's if I were going to start again. Since my longterm goal is to run some serious Rotrex boost, I don't think that ITB's are something I will spend more time on; the effort will be directed at making an intercooled (water to air) intake manifold eventually.

[mrphrancis013]

That is a shame. I agree about starting with Hayabusa ITB's. Glad to see you are still continuing on with the performance path. Water to air still baffles me when it comes to setting everything up. Do you have a link to the setup, I would like to see it. I might even be able to help with an idea on fab work.

[IDon'tKnow]

Starting on anything for a FI setup for this motor isn't going to start for another few years at te least. I still have tons of things to do to finish this motor in NA trim and get it up and running in my MR2. My build thread is over in the builds section.