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Discussion Starter #1 (Edited)
First in a series of step-by-step tech articles:
Crossfire TB Rebuilt Including new Shaft Bushings


http://www.thecubestudio.com/CrossfireThrottleBodyRestoration.htm

The series is written for Crossfire, but this article applies to any Throtte Body.

Here is the follow-on article about how to install and REAM bushings for a proper fit. Article on how to install sealed ball bearings will be next:

PLEASE NOTE: These articles are being revised and updated based on reader feedback, the links do not change, so hit them again to get the latest version

REV 03 05/20/08

http://www.thecubestudio.com/CrossfireThrottleBodyRestorationREAMEDBushings.htm
 

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Discussion Starter #4
Project: 2.375" CROSSFIRE Throttle Bodies on and Offy CROSS RAM

Two Crossfire Throttle bodies bored to 2.375" will flow over 1,000 CFM. Perfect for an Offy Cross RAM on a hi revving 406 small block with all forged internals. More pics as the project goes along. Feel free to ask questions.

Here is the first mock-up . . gotta love that Offenhauser!:



This is the throttle body. 2.375" absolute max bore for crossfire, yet with functioning balance port!



I will be doing custom elonkage and brackets as well as a custom fuel system for the project. Here is fuel system mock up:

 

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DC Pit Crew
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went ahead and consolidated your threads to make it easier to search for in the future :thumbsup:
 

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Looks pretty cool man. I'm not knowledgable at all on the Crossfire, so this will be interesting to follow. Oh, and it looks like you may need bigger fuel lines, lol. J/K.

Josh
 

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How about this for a Rube Goldberg method for plugging the IAC holes. Get a 6" or less piece of old bicycle tire, roll it in a cylinder, put it in the hole, put duct tape over the top. If there is a leak, duct tape will want to pull into the hole. Just press down duct tape to stop the leak. Works great and free.

Also, on the manometer, I have an analog guage that I use. Really like it. Someone gave me one in the past. Wish I had two. That way, I could hook up one to each TB and really fine tune them.

I use the adjustment screw on both TB's. Cover punched out on both. I find the balancing screw too difficult to use. I've got them both dead on 6" and the TPS dead on .525.

Idles smoothly, no hesitation, etc. 205K miles and still purring.
 

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DC Crew
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I "stuck" this thread for now.

Interesting read. :thumbsup:

I always thought that the crossfire properly tuned worked very well ... :thumbsup:
 

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Discussion Starter #9
How about this for a Rube Goldberg method for plugging the IAC holes. Get a 6" or less piece of old bicycle tire, roll it in a cylinder, put it in the hole, put duct tape over the top. If there is a leak, duct tape will want to pull into the hole. Just press down duct tape to stop the leak. Works great and free.
Awesome idea . . but we used the last of the duct tape holding the exhaust pipes on. ;)

Also, on the manometer, I have an analog guage that I use. Really like it. Someone gave me one in the past. Wish I had two. That way, I could hook up one to each TB and really fine tune them.
I've only seen anaolg gages that sensitive in a photo once. I looked around for one a couple years ago and didn't find any. All digital now. There are digital differential manometers, that would do the same job as a water manometer or as you said, two analog gages, but I don't know if the reaction time of the digital differential is fast enough to be usefull in this application.




BTW, I just received the tubing and fittings for this project and the raw materials (aluminum plate, stainless rod, etc) shipped yesterday, so expect more pics soon.
 

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Discussion Starter #10
Here is the final mock-up.

The green foam blocks represent custom pieces that I will be machining from billet aluminum. All of the adapters are 3/8" NPT, so even if the main supply line has to go to 1/2" we're covered.

The 'Y' block on the retun (lower right) will not actually have two outlets. These are alternate locations for the tie-in to the oringial steel lines. One of the taps points straight off the lid and there is a valve cover out there somewhere, so if that tie-in cannot be made with a smooth bend, the other tie in is available as an alternate. The unused one will be plugged.

Both IAC's have room for their plugs and there is clearance for the throttle AND cruise control cables to sneak in between the supply and return lines. The IAC on the front TB cannot be removed without taking the fuel rail out. I'm not satisfied with that and I might be able to adjust the supply enough that the IAC will come out without disconnectng the fuel lines. I'm not going to do any final adjustments like that until the TB's are mounted in their final positions. Raw materal for the TB adapter plates arrives tomorrow.




Note the use of the original crossfire throttle cable and TV cable brackets. On this project, the owner is doing his own brackets, but I still had to mock up something to check clearances with the fuel setup. I had these two original brackets from the BIG TB project, so I slapped them on the Offy to check my fuel line clearance and was shocked so see that they just fit perfect!

The owner will still going to do his own thing with the brackets, but for my purposes, I will make up new mounts for the original unmodified crossfire brackets, Normally I won't do that because it gets ugly and busy looking, but in this case, I just need some small plates - represented in the mock-up by the pieces of white poster board - which I will blast heavy to simulate the cast aluminum look and hopefully blend in nicely with the manifold.

The front plate will double as the 'Y' block mount. So the throttle bracket mount is a 'freebee' because I had to make a mount for the 'y' block anyway. The fuel rail will alos have it's own hard mount, but that is not shown in this mock-up.

The TV mount in the back will be smaller than shown in the mock-up. It will follow the contour of the bracket base and be almost unnoticeable. By using the stock crossfire brackets, this setup practically becomes a 'plug and play' for any car originally equipped with crossfire.

All you need is the TBs, linkage, TB mounting plates, and bracket mounting plates and you're ready to bolt on an awsome custom setup like this!




The owner is also doing his own air cleaner, so I won't be posting about that.
 

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Discussion Starter #11
Some progress to report:

Right now I am just making the mock ups into real pieces. Here is the adapter plate to mount the TB. Note the clearance cut for the linkage arm . . . little surprises .. part of the job. The blasted finish blends in with the rest of the mass of cast aluminum and makes the plate much less prominent.



Fuel return 'Y' block - this guy was interesting to make. Turned out pretty close to the mock up:



And the fuel supply rail. I would have preferred for this to be longer, but then I would have to come out at a 90 instead of off the ends with smooth transition 'port' fittings, so it would not have been a good trade-off.



A few more of these parts and I'll be able to do the final assemby. That's the fun part! These pieces are blasted for now . . might be polished later.

 

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Discussion Starter #12
Progess on the setup has progressed.

Here are the last couple of parts that I fabbed to mount the 'Y' block, fuel rail, and throttle cable bracket:



Goes together like this:





And the completed assembly looks like this. Both the supply and retun lines were moved down significantly. I've been thru the wrench clearance checks and stuff like that. The system is maintainable and even the IAC motor can be changed out now without pulling the fuel system apart.

Clearance issues with the valve cover and throttle cable have been resolved.






There are a few minor details to address. I am going to make a more robust fuel rail mount as I'm not satisfied with the one pictured.

I have to do a final mount of the TBs and then balance them. Next build up the injector pods and pressure test the whole system.

Then the whole assembly gets shipped to its owner who will be doing the install and air cleaner. That should be interesting to watch also!
 

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Discussion Starter #17
New article about fixing damaged Collector Edition hatch release cable - small, but important to CE owners and applies to others as well:

http://www.thecubestudio.com/CrossfireTechFixingCollectorEditionHatchCable.htm


Next will be rebuilding the injector pods. This will cover some advanced topics like cutting pressure taps for gages and using new regulator springs to boost pressure.





Also will be finishing the Offenhouser thread and starting a new thread on the Dually project I just shipped. I have lots of pictures of the whole mock-up and build.

 

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Looks like the guage covers up the thing for the air cleaner cover post?

I put a pressure guage on the side of the front tbi - where you have a blue thing or something tapped in. Used two 90 degree brass nipples so I could drop it down some and toward the back. Fits nicely within the a 9" K&N air filter.
 

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Discussion Starter #19
Tapping in on top (the blue bushing) on the front TB as you did is a good spot. That is above the 'compensator' diaphram and gives a good indication of what the sysem sees.

Very sharp eye about the air cleaner stud.

The photo shows the pod temporatily installed on my wife's CE to verify the bench setting of 16lbs. That pod (and it's twin) have 454 injectors and went out on the dual quad setup with the gage and fitting removed and a plug in it's place.

I install a gage (in one of several ways depending on the setup), check and set pressures and then remove the gage.
 

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Discussion Starter #20
OK here is the final assembly photos. Sorry it took so long.

Owner requested the whole fuel system be moved down and sent this sketch:


So, I took a deep breath and asked for a photo showing how much space I had below the rim of the lid and got this back (I added the red line):


The redesign resulted in these parts getting the axe:



Note that the 'Y' block had already been replaced once due to an SFU (Simpson Foul Up) so I just played around blinging up the old one.


 
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