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Thread: MPI throttle body options

  1. #16
    RIP EagleMark's Avatar
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    Mine measures 75mm at bottom, has small lip before blade 74.5mm but above blade is a lip that is less but can't get to to measure. Looks like some kind of venturi effect for air just above blade.

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  2. #17
    Super Moderator Six_Shooter's Avatar
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    The 4.3 Vortec TB does have the added on air diverter/flow reducer/restriction/progressive opening assist/whetever you want to call it piece.
    The man who says something is impossible, is usually interrupted by the man doing it.

  3. #18
    Fuel Injected! jameslleary's Avatar
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    I dont know where my post went from yesterday, but you can find 4bbl t bodies on old early mpfi caddys.

  4. #19
    RIP EagleMark's Avatar
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    Nothing has been changed or removed but I will watch for issue, you may have made a mistake in posting with Quick Reply? I did that twice now.

    So there is a four barrel TB!

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
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  5. #20
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    How early for the 4BBL Caddy? Are you talking about the EFI'd 472 / 500 from '76?? I have owned a few Caddy TBs and I have one from a 4100 in the barn. All that I've seen going back to 88 or so are 2bbl. Caddy did a strange thing in GM land and used an external motor that operated the throttle linkage to control idle speed. There was a switch in the motor that would close when the throttle was closed to let the ecm know to resume active idle speed control.

    The Vortec 5.0 / 5.7 TB is the same from introduction in 1996 to 2002 when the engine was phased outl Yes, anyone buying a bored L30 / L31 TB without making changes to the manifold is wasting $$. My understanding about the air deflector is that it helps create turbulence which better distributes EGR in the maniflold. I removed it from the TB I used on the intake in the picture. If youve seen a bunch of 4.3 TBs maybe it's easier and cheaper to remove one and take measurements? I could snap some pictures of the V8 TB's I have here for comparison. Also, Im not sure of pricing there but I can probably get a cheap V8 TB here. Those vehicles are old enough the salt has turned most of them into garbage. I'm likely heading to the yard on Thursday to get some parts for my Yota.

    Six, thanks for confirming the air deflector on the 4.3 units.

  6. #21
    Fuel Injected! JeepsAndGuns's Avatar
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    Ok, 1project, the TB you have is a 454 one and has a 80mm blade?, and eaglemark, yours is 75mm and is from what? Guessing 350?
    So am I reading the info right, just like the tbi units, the 454 has a larger bore than the 4.3/5.0/5.7 tb?

    Also pics would be great!! Most of the pics I see on ebay are not that great.

    Oh, one last request. Can anyone provide a rough measurement from the cnter of the tb to the outer part of the throttle linkage? Just wanting to make sure I have clearance for it. Cause the dodge tb is too wide. I have roughly 3.5 in from intake centerline to the rail. I think one of the biggest problems was the dodge linkage hung down below the shaft center.
    79 Jeep Cherokee, AMC 401, T-18 manual trans, hydroboost, 16197427 MPFI system---the toy

    93 Jeep YJ Wrangler, 4.0L, 5 speed, 8.8 rear, homebrew hub conversion and big brakes, hydroboost, 2.5in OME lift, 31x10.50's---the daily driver

    99 Jeep WJ Grand Cherokee limited, 4.0L, auto, 2wd, leather and power everything, 99% stock---the long distance highway ride.

  7. #22
    RIP EagleMark's Avatar
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    I took pictures already but can't find my camera cable... I don't know what it was off of, it was brand new, trying to figure that out here but still no clear cut answer to what mine measures? I got it for $50 shipped if thats fair? I had it 2 years for the six cylinder 258 jeep motor in my scout but it got sold. Would look better on your project then my wall!

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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  8. #23
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    Jeepsandguns,

    The throttle body in the pictures of my intake is from a 454. That picture is several years old. Ultimately I used a 350 / L31 throttle body with that manifold. I do not believe I still have the 454 TB although it may be in a box of parts in the barn. If I don't have it then I can only guess that I gave it away.

    The measurements are from a 350 / 305 throttle body that was on the bench at work this morning. It is not mine. It belongs to the company I work for and was on an intake that was being removed from a junk 350 to be reinstalled on a new engine. That TB is now installed in the van with the new engine. Next week I will have access to another TB as we have another engine to change.

    I wouldn't make any guesses about the 454 TB at this point.

  9. #24
    Fuel Injected! jameslleary's Avatar
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    Im thinking the 79ish models...saw a 4 barrel on a 4 6 8 and some of the others, non multiple displacemement models.
    EM...I may have fat fingered something on my orignal post....not the first time. trying to get used to the touch screen on this new I pad.
    Last edited by jameslleary; 11-16-2011 at 06:33 AM.

  10. #25
    Fuel Injected! JeepsAndGuns's Avatar
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    Quote Originally Posted by 1project2many View Post
    Ultimately I used a 350 / L31 throttle body with that manifold.
    Just out of curiosity, what made you sawp tb's? Too much air flow, or other reasons?
    79 Jeep Cherokee, AMC 401, T-18 manual trans, hydroboost, 16197427 MPFI system---the toy

    93 Jeep YJ Wrangler, 4.0L, 5 speed, 8.8 rear, homebrew hub conversion and big brakes, hydroboost, 2.5in OME lift, 31x10.50's---the daily driver

    99 Jeep WJ Grand Cherokee limited, 4.0L, auto, 2wd, leather and power everything, 99% stock---the long distance highway ride.

  11. #26
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    The throttle linkage doesn't work. The 454 TB is designed to be mounted vertically with the cable pulling from the manifold side. The 350 is designed to be mounted horizontally with the cable pulling from the front.

    The 350 TB provides more air than that engine needs. It's a 302 Chevy with LT4 cam. It may top 350 hp but probably not.

  12. #27
    Fuel Injected! JeepsAndGuns's Avatar
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    Well I was bored this moring while waiting for it to be time to go to work. So I was googleing this illusive 4 barrel caddy tb, just cause I wanted to see what it looked like. (I had no luck, all I could find were 2 barrel units)
    But while looking on ebay, I found this:
    http://www.ebay.com/itm/Cadillac-Dev...item20ae0001d6
    Looks almost identical to the tb style we have been talking about. I remember seeing 2-3 of the 00 and up northstars at the pull a part when I was looking for a dis coilpack. (noticed those didnt have it) Now I dont know what the bore dia of these northstar tb's are, but its worth a trip to drive down there and see, cause tb's are dirt cheap there.
    Guess I know what I am doing this weekend.
    79 Jeep Cherokee, AMC 401, T-18 manual trans, hydroboost, 16197427 MPFI system---the toy

    93 Jeep YJ Wrangler, 4.0L, 5 speed, 8.8 rear, homebrew hub conversion and big brakes, hydroboost, 2.5in OME lift, 31x10.50's---the daily driver

    99 Jeep WJ Grand Cherokee limited, 4.0L, auto, 2wd, leather and power everything, 99% stock---the long distance highway ride.

  13. #28
    Fuel Injected! JeepsAndGuns's Avatar
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    Well made it back from the pull a part. Those 2-3 00 and up northstars disappeared (crushed mabey?) and only one was left. I got to it and the engine was gone (****), I walk about 2-3 cars down and theres the engine setting upside down on the ground in front of another random car. Whatever that was all about...but anyways. I looked at the TB and it had a chip knocked out of it where the intake/air filter hose connects to (****!!) I pull it off anyways so I could measure it. I removed the blade so I could get a accurate measurement. It sits dead on 75mm. The bore of the tb itself is exactly the same all the way through (where its machined that is) No taper above or below the blade. Looks identical to the one in the ebay link in my last post. Because it had the chip I set it on the engine and go looking for other ones. I check out the older northstars. I pulled one of those and measure it, and it measures dead on 73mm, and tapers in just below the blade. They also have a funky bolt on air intake hose. I move on. I get to a vortec 4.3, pull the tb and measure, its the same as the northstar, 73mm and has a taper below the blade, and then also has the deflector riveted to the blade. I actually found a vortec v8 (dont know if it was 5.0 or 5.7) but someone had robbed the heads off it and set the intake in the cab. I pull it and measure. same as the older northstar and 4.3, 73mm and tapers in below the blade. It was identical to the 4.3 tb and had the air deflector thingy on the bottom of the blade, but was only about half the size of the 4.3 one.
    A full sweep of the yard nets me no luck on a better caddy unit. So I go back to the chipped one and I think I can fix it with some JB weld and it be fine. They knocked a few bucks off the price because of the chip. Dont guess its too bad for $27. If the JB weld doesnt work, I'm not out much money. Once I get home and start carrying my tools and stuf in, I set it on the bench and then accidently bump it and knock it off. Falls straight on the IAC and busts the plastic part of it the wiring plug goes in, into 1000 peices TPS is still fine though. Looks like I will be going back to get another IAC. May wait a few weeks and they might get another late model caddy in. The IAC and TPS on it and the vortec tb's all look the same, not sure if the iac pintle is any diffrent though.

    A little test fitting on my intake and I'm still not gonna have enough clearance to put it on vertical. The throttle cable linkage still hits the fuel rail

    So, I am holding it and playing with diffrent ways to mount it, what, if any disadvantages would it do to make a 90* elbow to where I could bolt it on facing forward? Actually, when playing with it, if it could be done without it affecting any performance or cause any airflow problems, is there any reason I couldnt put it at a 45* angle to the engine centerline? Meaning have the elbow point the tb forward, but pointing to the drivers side (almost facing the headlight). That would give it clearance for the thermostat housing and oil fill tube, and also point it right at a nice area to mount a air filter.
    79 Jeep Cherokee, AMC 401, T-18 manual trans, hydroboost, 16197427 MPFI system---the toy

    93 Jeep YJ Wrangler, 4.0L, 5 speed, 8.8 rear, homebrew hub conversion and big brakes, hydroboost, 2.5in OME lift, 31x10.50's---the daily driver

    99 Jeep WJ Grand Cherokee limited, 4.0L, auto, 2wd, leather and power everything, 99% stock---the long distance highway ride.

  14. #29
    Fuel Injected! JeepsAndGuns's Avatar
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    I did a little looking online and found out (from simply looking at pictures) that this 00 and up (I think to 04?) northstar tb is a mirror image of the LS tb's. With the inlet facing you, the northstar throttle linkage is on the right, where the LS is on the left. Everything else on it is a mirror imige of the LS unit. Only thing I saw diffrent was there are two little vaccume hose tubes on the bottom of the LS units, where the caddy does not have them. The bosses are there, but not drilled.

    So does anyone have any opinions on the mounting position I mention in my last post???
    79 Jeep Cherokee, AMC 401, T-18 manual trans, hydroboost, 16197427 MPFI system---the toy

    93 Jeep YJ Wrangler, 4.0L, 5 speed, 8.8 rear, homebrew hub conversion and big brakes, hydroboost, 2.5in OME lift, 31x10.50's---the daily driver

    99 Jeep WJ Grand Cherokee limited, 4.0L, auto, 2wd, leather and power everything, 99% stock---the long distance highway ride.

  15. #30
    RIP EagleMark's Avatar
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    Since it's MPFI I don't think it would matter if you mounted it flat or built an adapter with elbow. Lot of work to build an adapter with the elbow. Since there's differences in these as far as which way the throttle cable works I would rather start with one that pulls just like a normal carb or TBI that came on the vehicle and keep that mounting position.

    Can you make the adapter thicker to raise the throttle body to get clearence needed? I just looked at mine and could whack off the extra throttle cable linkage that would hit adapter plate when at WOT. But it is still front pull, not rear pull. Which was what I wanted for the six cylinder I was going to use it for. But now looking at it if it were on an elbow adapter pointing forward the rear cable pull would work.

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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