3.6 ITB Project

[Jim2]

Noticed a few threads lately about various ITB installations so I thought I'd show mine.

I'm a turbo guy and this is the first non-turbo car I've built. The car itself is a partnership with my race partner who is 74 but remains a hardcore Porsche nut. This ITB motor was destined for our RSR replica race car but the project stagnated a number of years ago. The motor had been overhauled but needed ITBs, injection, exhaust etc etc.

A couple months ago we picked up a local track rat roller figuring it would be an opportunity to complete the motor and tune it. If the day comes that the RSR replica is completed the motor will be complete, tuned, and ready for installation.

I'm a fabricator of sorts and my objective as usual is to spend as little money as possible by building whatever parts as I can. The ITBs are hand built using donor components from junk yard throttle bodies, throttle shafts, butterflies, shaft bearings, return springs, levers, ball socket joints and cross shaft are donors from some old MFI TBs which had corroded bodies.

The TB id is 49mm and tapers down to 44mm at the port. Overall length of the TBs is 12". The motor is a 964 platform mildly ported, some cam which Dema Elgin suggested, and stock pistons, rods etc. Won't be twisting this one very high with the stock rods and bolts.

Injection and ignition will be controlled with SDS EFI and though I'm expecting to use throttle position input as opposed to manifold pressure, I'm going to try to tune using MAP but won't be surprised if the results are poor due to lack of vacuum signal. I built manifold vacuum ports along with a small accumulator but don't know if this will be effective.

Headers are 1.75" OD primary shorties connected to a *cough* bursch muffler with a 2.5 superflow can. The partner wanted a modified factory 2 in/ 2 out but I talked him out of it in an effort to save my hearing.

Anyhow, here are some pictures I grabbed with my phone.




Here's a shot of the car, a local friend built it and ran it for a few years before selling it. Big torsion bars, sway bars, polybronze, 930 brakes, fuchs/BBS 17x8 and 17x10.







Here I mocked up the installation on my work bench so I could figure out how to orient the lever arms and return springs.


This is prior to welding on the velocity stacks, and no butterfly shaft. Straight shot to the intake valve!




Only a few items remain before it runs, wiring, vacuum hoses, install O2 sensor, breather hoses, oil, gas. Hopefully by the end of the week.

Back to work.










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[James Brown]

looks great, Al, you seeing this??

[al lkosmal]

I'm seeing and I'm really liking it..........love the DIY aspect...very nice work. What are the t'bodies originally from? . My experience leads me to believe that your MAP signal should be ok, using the accumulator. If you get low or no MAP signal......check for vacuum leaks......and then check again.

Please keep us posted regarding the tuning using the SDS unit. I have been using Megasquirt and EDIS with very good results, but I'm always interested in alternatives. We EFI/ITB/DIY guys have to stick together and compare notes.

Here' a link to my you tube channel for a peek at my various EFI projects....and others.

koz77911's channel - YouTube

Nice................

regards,
Al

ps: James, where have you been hiding...............stop by and check out my new ride.

PSS: Jamie...are you checking this out?

[jpnovak]

Very cool.

That looks like MFI linkage welded onto the existing arm. Very cool.

Are those welded to a factory 3.6 injector base? They look the same but I thought they were plastic.

[Tippy]

Argh...must......not......look.

That car is really nice and the color is stunning. Love the ITB's. What did you get the ITB's from?

[Jim2]

Tippy, as I mentioned this car is a track rat, 10 footer. Color is good but also likely to attract the wrong kind of attention.

Al and Jamie, hehe, trust me, I've read every one of your efi/itb posts, just think of it as internet stalking. Guys like you feed my addiction!

The few donor parts used to build the stacks were MFI lever arms, linkage rods and ball sockets, and the cross bar. The stack body is mostly hand built except for the bearing holder.


.
Flanges are .750 thick and copy the base of the stock plastic part:








.
The parts for the throttle section came from some Hyundai, they started at 53mm but I sleeved them down to 49mm. The portion I was after was the bearing holders. It's a tough section to reproduce with basic manual machinery.

I paired the TBs down until I had only a collar with the bearing holders. This looks like lots of work but this part was simple and fast, less than two hours. To construct the stack bodies went quick. Finishing all the details took a significant amount time, and usually more time spent thinking than doing.





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I machined a sleeve which interference fits inside the the TB bore taking it down to 49mm.



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The lower riser tube had a tapered die pressed into it expanding one end to 49mm to match the TB, then I welded the unit together. The 41mm end of the flange was hand ported to match the intake ports at 44mm. I also machined o-ring grooves into the flanges as opposed to using gaskets.




.
Spun the velocity stacks:






I was thinking of ITG filters but adding flanges to the stacks and air horns meant more work, and of course ITGs aren't cheap. Instead I asked Al about some of the filter socks he was using and went ahead and ordered Uni filter socks. Today I finished the fuel lines and mounted the fpr. Tomorrow I'll do the vacuum parts and breather plumbing.

I need to revise the right header because it interferes with the clutch lever. This seemed odd because the headers were previously on a similar installation. This fix will easily eat a half a day. Also I need to add the boss for the wide band O2 which I forgot to install. Then, wiring...

[al lkosmal]

Jim...mad skillz..............Awesome project.

regards,
Al

[Elombard]

'I am a fabricator of sorts'

understatement of the year.

looks very cool - love the color on the car too.

[Tippy]

Nice, I need to hone my skills on the Bridgeport and do something similar. .

There has to be an EFI'd motorcycle out there with the right TB size?

[billjam]

From another "fabricator of sorts", love your ideas and workmanship.

[Jim2]

A few more hours in today, might even run tomorrow! Looking back, this project was a bit of a haul and I didn't really get my head wrapped around it until the last couple weeks when I could see the light at the end of the tunnel.

Bill, I haven't looked at your project lately, is it running yet? I recall your project looked well executed.

Tippy, fire up that machine or send it my way! BTW, I did some searching for TBs and didn't find much suitable other than what Al discovered. My partner already bought a box full of these Hyundai TBs so I felt compelled to try and make use of them. He was hinting at just making some adaptors to connect up to the factory plastic 964 stacks but he didn't realize that the TBs were simply too big at 53mm. I put my head to it in order to see if I could make use of the parts and realized after I built one unit, the other 5 were simple since the process was established. However I discovered the details are what took the most time.

[Flat6Heaven]

Amazing work, thanks for sharing!

Mind sharing where you are planning to install the O2 sensor?

Thanks in advance,
Ben.

[billjam]

Jim,
My 3.6 ITB project is sitting under a cover in a corner of the garage all ready to slip into my Carrera, however I have been sidetracked doing an engine-out fix of a few annoying oil leaks and a general clean-up on my 930 (and working for a living).
I love your method of spinning the velocity stacks. It's enough to make me want to start another ITB project!

I think you've made this project of yours look way too simple - like it's 5 minutes work to make up smaller butterflys, another few minutes to make and fit the internal sleeves, then maybe ten minutes with the die-grinder removing all the unwanted appendages on the ITBs!
Jim, you really have to stop making this stuff look easy.

[Jim2]

Bill, it sounds like you have your hands full with two cars on the go, I know the feeling,... now! I normally try and avoid having a second hobby car, there's enough projects to keep me busy with just one car (currently my turbo'd 993).

Contrary to the way it may appear, nothing went fast on this project, though motivation was certainly a big issue. Gone are the days when I used to work on these projects from 7 in the evening to 3 AM then get up and go to work at 6. Now I'm lucky if I can get my lazy butt off the couch and go into the shop on a week night. Burnt myself out abusing sleep.

I'm definitely more motivated during the summer and that's when I did the bulk of work on this project. One thing I'll say, it's deceiving which aspects absorbed the bulk of time hand building these parts. Lots of planning and head scratching to determine how to construct the parts, but not much time doing the actual construction. Final details also ate up many hours. Once again, the construction, machining and welding are something I do regularly.

Flatsix, I'll take a picture of the location where I stuck the O2 sender and post it up for you.



Happy to say, IT RUNS!!


My partner and I cleaned up a bunch of loose ends over the weekend and finally we were ready to run the motor at 7pm yesterday. Since this motor was fresh we pulled the plugs and turned it over on the starter until we had oil pressure for about 20 seconds. After a couple minor wiring snags we ran the fuel pump for a minute to get the air out of the fuel system. Hit the starter and the motor fired up after about three rotations, idling on it's own! We stood back and looked at each other somewhat shocked. All we had to do was turn up the idle stop screws a little. Having not worked with ITBs I presumed the motor would be idling rough and coughing but this was clearly not the case. One of the guys at SDS preprogrammed the ecu with values which he thought would get the motor running, certainly worked well.

We proceeded to calibrate the timing for the SDS computer then watched the AFRs which were fat, in low 10s, leaned it out a little and the idle picked up. Did a quick test with an old fashion unisync tool and adjusted the idle stops but haven't locked down any of the throttle rods yet.

After a quick shutdown to look for leaks we restarted and then of course cracked the throttles a few times, all I can say is Porsche music! It revs really fast. Tue or Wed I'll complete the sync of the throttles and lock all the rods then clean up a few loose ends with the wiring on the left frame rail. Install the air cleaners and drivers seat and it should be ready to drive and start tuning. I'll report back, and maybe add a video if I can figure out youtube.

Engine bay is done except for the air filters and the bit of wiring on the left frame rail. I managed to cut out some of the reverse light wiring and had to undo my wire wrapping to sort it out.

Thanks to the following guys for supplying various mechanical parts to put this thing together: Andrew15, Unclebilly, Haycait911.







I need to clean the glue off the firewall and clean the frame rails, had lots of opportunity to do this while the motor was out but I guess it fell off the list. Also the wiring in the left front corner looks pretty busy but this will get cleaned up now that I've figured out what I did wrong with my reverse light wire. The panel in the left front holds a map sensor, high idle air bypass, two relays for the coil driver box and coils, and the air temp probe which is visible just forward of stack #3.

Looks like I also need to install a breather hose on the oil tank, forgot about this. Picture seems to make the engine bay look busy with wiring and plumbing but it's actually tidy when looking at it look.


I mounted the ecu on the virtical panel behind the drivers seat. The PLX box operates the wide band O2 and is needed to process the O2 signal being delivered to the ecu. The relay provides power to the ecu and PLX. One in-line fuse for both devices as well. The hand held programmer for the ecu is connected via the white cable on the left. It will get removed once the programming is done.


I have a load of pictures taken during assembly and various mods to things like headers and such. Lots of work I've forgotten about!

[oldldh]

When I grow up, I'm going to be a fabricator of sorts...TOO!!!!

Mighty nice...

Larry

[NOLAsc]

Originally Posted by oldldh

when i grow up, i'm going to be a fabricator of sorts...too!!!!

+1

[James Brown]

check out his pictures of the build at the bottom of his page. under RSR project, fantastic job Jim

[Flat Six]

Originally Posted by oldldh

When I grow up, I'm going to be a fabricator of sorts...TOO!!!!

+1

My favorite understatement from the Man-of-few-words Department:

"Spun the velocity stacks"

[Chuck.H]

I for one would like to know more about the flaring Jim:

1) did you make that die that is holding the tubing and helping set the flare?
2) is the die in two pieces and sized so it clamps the tubing?
3) is that a bearing on the end of your tool to roll the flare?

Thanks!
Chuck.H
'89 TurboLookTarga, 336k miles

[totle]

Wow. Great skill here Jim.
Always impressed to see all the parts people makes themselves.