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75mm throttle body for 4.0L SOHC?


2000StreetRod

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Initial installation

I performed some voltage checks on my stock throttle body before replacing it. The voltage with ignition On, engine Off at closed throttle was 0.97 volts. That's slightly more than desired according to what I've read on this forum. At wide open throttle (WOT) the reading was 4.7 volts. The photo below shows the racing 75mm throttle body installed with a 1997 Expedition throttle position sensor (TPS) installed.
TPS.JPG

Visible in the photo are the M5-0.80x30 socket head cap screws (instead of the stock Phillips head) I purchased from Lowe's to mount the TPS to the throttle body. The photo below shows the 75mm throttle body with closed throttle.
INCLOSED.JPG

The thickness of the tapered adapter was just right for virtually no cable slack with the throttle control against the closed stop screw. The voltage reading at closed throttle is 1.03 volts (higher than I want). I noticed before using my Dyno-Scan that absolute throttle position was 18.8% for the stock throttle body at closed throttle.
The photo below shows the 75mm throttle body at WOT after connecting the throttle cable.
INOPEN.JPG

I wedged a pole between the accelerator and the seat back to check the throttle plate movement. The throttle control was against the WOT stop. The voltage at WOT is 4.7 volts. As I recall this equated to an absolute throttle position of 92.8%. I disconnected the negative battery terminal and then connected the cruise control cable and attached the main intake hose and associated hoses as shown below.
Complete.jpg

It was fairly difficult to force the stock intake tube over the larger than stock outside diameter of the 75mm throttle body. I had thoroughly warmed up my engine before replacing the stock throttle body to insure the engine wouldn't die when started with the 75mm throttle body. I reconnected the negative battery cable after more than 10 minutes and started the engine. The engine started fine and idled about the same (not stable and slow) as it did with the stock throttle body. I let it idle for 15 minutes so the PCM could begin to "learn" the new throttle body. During this time I watched the A/F ratio and detected nothing abnormal. I then spent about 10 minutes switching from Park to R to N to D to N to R to N to D letting the PCM further "learn" the new TPS and throttle body. Then I ran the engine at various speeds under 3,000 rpm. During all of this I watched the A/F ratio and nothing looked abnormal. Then I did a couple of throttle "blips" but still nothing over 3,000 rpm. The throttle response seems improved and the intake air flow noise is definitely increased. The noise increase could be partially due to the elimination of the "comb" gasket. No CEL was ever illuminated.

Next comes a test drive with my Dyno-Scan to monitor O2 sensors, absolute throttle position, MAF airflow and to watch the A/F ratio. I'll also check the cruise control to see if the cable needs to be adjusted.

I'm not satisfied with the larger closed throttle TPS voltage but I don't want to drill out the bushings to perform the slot adjustment mentioned on this forum. I think the bushings are an integral part of the physical strength of the TPS. I'll play with my stock TPS to try and find an alternative method.
 
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CDW6212R

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That's very good, and I like those TPS screws better than what I bought.

Don't do anything about the TPS voltage, that 1.03 is perfectly fine. What you have read about adjusting the TPS is all false, a complete myth.

The OBDII and newer PCM's do not have hard TPS voltage data in them. They all read the idle TPS each time the engine is started, and that is the point during that operation cycle that the PCM uses. It doesn't matter if it's off slightly from 1.0 volt, it is fine within say .3-.5 volts. Any TPS check is very easy now, the idle should be around 1.0v, and the WOT should be near and below 5.0 volts. You are done there, well done.
 




2000StreetRod

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worse gas mileage!

Well I can definitely state that my installation of a 75mm ported and polished racing throttle body adversely affects gas mileage. The reason, the engine is so much more responsive and fun to drive that I can't seem to keep from mashing the throttle! It may not actually be significantly more powerful but it sure seems and sounds like it is. I'm still keeping the maximum rpm at 3,000 until I accumulate 200 miles after adding gasket stop leak to the engine oil in hopes of stopping what appears to be a very slight rear main seal leak. It's going to take me a while to get used to it and return to my normal driving habits. No trip to the local dyno until after an oil change.

So far I have not detected anything negative resulting from the throttle size increase. The A/F ratio seems unaffected as does the idle. Tomorrow, if the weather is nice, I'm driving from Greenville up the mountain to Hendersonville. That will give me a chance to check out the cruise control. This morning I adjusted the cruise control cable to it's maximum length but there was only about 1/8 inch left to lengthen. I haven't figured out how that affects the cruise control speed range.
 








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Good, I just ordered a new cable(actuator) for mine. They are about $20 I think. Mine has not worked for about two years.
 




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Did you ever get it to the dyno it find out what the hp gains are?
 




2000StreetRod

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No dyno yet

Did you ever get it to the dyno it find out what the hp gains are?
No, I got involved in a custom tune and as soon as I completed that I pulled the engine to replace the timing chain components. I still plan to do some dyno testing after I get my engine repaired and installed.
 




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2000StreetRod

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that's a 70 mm

just to clarify, this is the right TB right?

http://cgi.ebay.ca/96-04-FORD-MUSTA...r_Truck_Parts_Accessories?hash=item19ba8e7597

then you just turn it around and hook it up?

can i use the stock TPS or can i use the one on the new TB

thx
That one is a 70 mm throttle body but it should work fine. It's what most people upgrade to. Mine is a Ford Motorsport 75 mm racing throttle body that never went into production. It has been ported and polished. You will lose a little resolution with the larger bore. However, I did not detect any noticeable degradation with my 75 mm.
 




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what do you mean by resolution? (noob q :p )
 








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IMG_20200731_221626798.jpg


I actually bought one of those 4.6 throttle bodys for my setup cuz the factory TB is def a restriction in my setup. I dont have exact measurements on me atm but i wanna enlarge the plenum inlet slightly and ill prolly have to make a new spacer (that white block in between throttle body and plenum) and i can make my IAC remote and retune iac if absolutely nec. However the 4.6 throttle body i got has a diff bolt pattern then my stock 01 explorer sport TB for some reason. The height and width of the center of the bolt holes doesnt line up. Of course i could make a metal spacer to accommodate it but my only concern is throttle body linkage. Ive been tryina work this out for a long time actually. I jus recently came up with the idea of using the plastic arm off my stock tb on the 4.6 tb but i dun think they rotate the same way or that i wuld even be able to unbolt or bolt the tb arms up. I was also lookin at 5.0 pushrod TBs and GM LS TBs. I def need a diff TB cuz it rlly is a restriction in my intake. But i first have to think abt makin throttle body linkage work then i have to make a proper spacer (white thing)for whether or not im gonna go remote iac or not and transition the spacer from the size of the TB to the inlet on the plenum, enlarging the plenum inlet port slightly will change spacer design of course. If the bolt pattern on a new throttle body is the same then i can use the same kind of material for the spacer, if the bolt pattern is different then i would prolly have to make a metal spacet so i can make threaded holes accordingly for tb and plenum bolt holes. Any ideas or help would be greatly appreciated and i can can get measurement numbers if nec. But forreal tho it doesnt make any sense that the TB bolt patterns dont coinside for me. Ppl always be tlkin bout the 4.6 tb swaps on the 4.0 SOHC but the few diff 4.6 throttle bodies ive tried to fit have diff bolt patterns then mine if im remembering correctly nd im decently sure i am. I still have a brand new polished 4.6 tb sittin around and stuff for remote iac.
Heres a link to the same throttle body that i have but i forget if mine is 70mm or 75mm.
My intake tubing is 4 inches, yes i kno ridiculous even for a m90 supercharger. I shulda went with 3.5 or 3 inch instead lol but 4 inch is def the max i can fit lol and if i get this TB issue worked out with porting the plenum inlet as well then i can move onto port matching the plenum outlet to the port matched m90 s/c inlet and port work on the rest of the blower casing and then rebuild and get a smaller sc pulley and grind the snout down so that i can use pulleys small enuff to run up to like 15 lbs of boost. Then i wouldnt have to worry bout any restriction in the intake, at that point i may have to start thinkin bout runnin a proper dual exhaust and ditchin the y pipe for better exhaust flow.

If that ends up goin well then id reallly like to do cosworth DOHC cyl heads but thas alot to work out especially if i wanna keep runnin my blower. Ive decided no v8 for this truck prolly ever. Next xplr will have a v8 dohc. But with a cosworth dohc cyl head swap im worried bout configuring the timing drive properly and if the fuel rails will be able to fit underneath my intake manifold which ill have to make a new one or modify the stock one to match the intake ports on dohc cyl heads. And i also think that for the top part of the engine block your supposed to use an OHV block unless im wrong and an entire sohc block is viable for dohc heads but i think i read that your supposed to use an OHV block with pushrod dummy plugs with a sohc bottom end. cuz the write ups ive seen like aren't completed so if anybody has info on that get at me please.

I was also thinking that if I could find a 4.6 tb with a proper bolt pattern that has one of those plastic arms on the side of it instead of that metal linkage like the 4.6 tb i have laying around then I might be able to rotate the throttle body clockwise 90 degrees on the white spacer and relocate the iac valve for remote mounting or install it in some other position, that way there would be room on the right side of my throttle body for me to rotate it clockwise 90° and put the throttle body arm on the right side because I think that would help with lining up the cables because I'm pretty sure that the TB arm on the 4.6 TB rotates opposite of the way mine does. If I had the TB arm on my current stock tb on the right side instead of on top then the throttle cable would route above and with the 4.6 tb it would route below.
 
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Blown

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Sounds like a fun build! I am running 5lbs of boost in my 4 door, fresh, relatively stock 5.0 I found an old F150/Bronco kit and modified it to fit. It is old enough to not have a built-in bypass and that is why I am keeping boost down for now. I believe I can add one and have the parts to do so eventually.

How much boost are you running now and do you have pics of your intercooler under the blower?
 




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Sounds like a fun build! I am running 5lbs of boost in my 4 door, fresh, relatively stock 5.0 I found an old F150/Bronco kit and modified it to fit. It is old enough to not have a built-in bypass and that is why I am keeping boost down for now. I believe I can add one and have the parts to do so eventually.

How much boost are you running now and do you have pics of your intercooler under the blower?
You can definitely add a bypass to the setup probably. I might even try and find a way to vent it to atmosphere if it was me like on a pro charger or a vortec. What brand is the kit you're talking about that you found from an f150 or bronco? And I'm running 7 to 8 lbs of boost right now on my m90. But once i build a proper performance 4.0 sohc (or dohc lol) motor nd take care of the TB restriction in my intake, I'll rebuild nd port the m90, port match the plenum and grind the snout down so I can run a pretty small pulley and see how much boost and power I can get out of it and if it does this safely and reliablely I'll step up to an M112 cobra style blower, I got a couple of those laying around too for my cobra. I was thinking of going with the lightning style m112 but I happen to have a couple Cobra ones and I think the Cobra ones will allow me to set up the intake better than a lightning one.
 
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Devan

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that's a 70 mm



That one is a 70 mm throttle body but it should work fine. It's what most people upgrade to. Mine is a Ford Motorsport 75 mm racing throttle body that never went into production. It has been ported and polished. You will lose a little resolution with the larger bore. However, I did not detect any noticeable degradation with my 75 mm.
Is the bore of your spacer inlet the same size as your throttle body bore? And is the outlet of your spacer bore the same size as the bore on the intake manifold? And what is the bore diameter of your throttle body?
 




Devan

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Initial installation

I performed some voltage checks on my stock throttle body before replacing it. The voltage with ignition On, engine Off at closed throttle was 0.97 volts. That's slightly more than desired according to what I've read on this forum. At wide open throttle (WOT) the reading was 4.7 volts. The photo below shows the racing 75mm throttle body installed with a 1997 Expedition throttle position sensor (TPS) installed.
View attachment 56508
Visible in the photo are the M5-0.80x30 socket head cap screws (instead of the stock Phillips head) I purchased from Lowe's to mount the TPS to the throttle body. The photo below shows the 75mm throttle body with closed throttle.
View attachment 56509
The thickness of the tapered adapter was just right for virtually no cable slack with the throttle control against the closed stop screw. The voltage reading at closed throttle is 1.03 volts (higher than I want). I noticed before using my Dyno-Scan that absolute throttle position was 18.8% for the stock throttle body at closed throttle.
The photo below shows the 75mm throttle body at WOT after connecting the throttle cable.
View attachment 56510
I wedged a pole between the accelerator and the seat back to check the throttle plate movement. The throttle control was against the WOT stop. The voltage at WOT is 4.7 volts. As I recall this equated to an absolute throttle position of 92.8%. I disconnected the negative battery terminal and then connected the cruise control cable and attached the main intake hose and associated hoses as shown below.
View attachment 56511
It was fairly difficult to force the stock intake tube over the larger than stock outside diameter of the 75mm throttle body. I had thoroughly warmed up my engine before replacing the stock throttle body to insure the engine wouldn't die when started with the 75mm throttle body. I reconnected the negative battery cable after more than 10 minutes and started the engine. The engine started fine and idled about the same (not stable and slow) as it did with the stock throttle body. I let it idle for 15 minutes so the PCM could begin to "learn" the new throttle body. During this time I watched the A/F ratio and detected nothing abnormal. I then spent about 10 minutes switching from Park to R to N to D to N to R to N to D letting the PCM further "learn" the new TPS and throttle body. Then I ran the engine at various speeds under 3,000 rpm. During all of this I watched the A/F ratio and nothing looked abnormal. Then I did a couple of throttle "blips" but still nothing over 3,000 rpm. The throttle response seems improved and the intake air flow noise is definitely increased. The noise increase could be partially due to the elimination of the "comb" gasket. No CEL was ever illuminated.

Next comes a test drive with my Dyno-Scan to monitor O2 sensors, absolute throttle position, MAF airflow and to watch the A/F ratio. I'll also check the cruise control to see if the cable needs to be adjusted.

I'm not satisfied with the larger closed throttle TPS voltage but I don't want to drill out the bushings to perform the slot adjustment mentioned on this forum. I think the bushings are an integral part of the physical strength of the TPS. I'll play with my stock TPS to try and find an alternative method.
This is the throttle body that I have with the metal cable linkage arm. SR perf 75mm for 4.6 sohc
Sr perf 75mm TB
The one that street rod has pictured above has a plastic arm on the side but after closer inspection it looks like both arms hold the cables the same way for the 4.6 unless I'm mistaken. Here's a link to one that I found with a plastic arm instead.
Accufab 4.6 TB

If somebody could give me length by width measurements of the center of the TB bolt holes for their 4.6 and/or 4.0 TBs id appreciate it. Because like I said before the 4.6 TB that I have, has a different bolt pattern than my 4.0 TB which makes no sense because here we are on a forum where somebody has installed a 4.6 TB onto their 4.0 intake manifold.yes I know that Ford uses like four or five different intake manifolds for the Ford 4.0 sohc but I still don't get why my bolt pattern seems different on my 4.6 TB.
 




2000StreetRod

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Is the bore of your spacer inlet the same size as your throttle body bore? And is the outlet of your spacer bore the same size as the bore on the intake manifold? And what is the bore diameter of your throttle body?
Yes, I used a drum sander to taper the bore of the spacer to match the outlet bore of the throttle body (76.2 mm) and the inlet bore of the intake manifold (64.7 mm). The throttle body inlet bore is 77.0 mm.
 




Blown

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You can definitely add a bypass to the setup probably. I might even try and find a way to vent it to atmosphere if it was me like on a pro charger or a vortec. What brand is the kit you're talking about that you found from an f150 or bronco? And I'm running 7 to 8 lbs of boost right now on my m90. But once i build a proper performance 4.0 sohc (or dohc lol) motor nd take care of the TB restriction in my intake, I'll rebuild nd port the m90, port match the plenum and grind the snout down so I can run a pretty small pulley and see how much boost and power I can get out of it and if it does this safely and reliablely I'll step up to an M112 cobra style blower, I got a couple of those laying around too for my cobra. I was thinking of going with the lightning style m112 but I happen to have a couple Cobra ones and I think the Cobra ones will allow me to set up the intake better than a lightning one.
I overpaid for a used Kenne Bell F150/Bronco kit from Kenne Bell. I got only one pulley that will work, two pulleys too small, a 2.2l supercharger, front snout bracket, and throttle bracket. I had to fab-up some parts, modify some, and likely will refine some work as I go.................It's a hobby and much cheaper than getting something new.

I have a vacuum operated bypass and think I know How I will plumb it back to the intake pipe. The truck is running great and at only 5lbs I have not seen a high IAT. Heat is the issue with roots type or twin screws and running without a bypass creates more heat. The centrifugal, Powerdyne, Vortec, Pro Charger style blowers place the blower before the throttle plate, shut it down quick and there can be a lot of force behind the throttle plate and I hear damage to the blower.........................I have run a Powerdyne at 6lb in a Bronco as my first Supercharger, no bypass, but again lower boost and temps anyway. I prefer the positive displacement blowers as the boost comes-on much lower RPM for daily driving and pulls you off the line in these heavier vehicles, heat is a concern. I think it is even more a concern with the 5.0 wedged into the engine bay. I am thinking I wont add boost till I can figure a way to cool the intake charge and I think I am going to try to tune to a 180 degree thermostat for Summers...................................am pretty sure the boost is building earlier in RPM's without a bypass.

I guess I could build a box/heat exchanger to install between the supercharger and upper manifold it came with. This is what I got:
f150-_-full-size-bronco-5.0-_-5.8-supercharger-kit.jpg


Lots to consider on these builds...what are you tuning with??
Go man, fun stuff as always!
 
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CDW6212R

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I overpaid for a used Kenne Bell F150/Bronco kit from Kenne Bell. I got only one pulley that will work, two pulleys too small, a 2.2l supercharger, front snout bracket, and throttle bracket. I had to fab-up some parts, modify some, and likely will refine some work as I go.................It's a hobby and much cheaper than getting something new.

I have a vacuum operated bypass and think I know How I will plumb it back to the intake pipe. The truck is running great and at only 5lbs I have not seen a high IAT. Heat is the issue with roots type or twin screws and running without a bypass creates more heat. The centrifugal, Powerdyne, Vortec, Pro Charger style blowers place the blower before the throttle plate, shut it down quick and there can be a lot of force behind the throttle plate and I hear damage to the blower.........................I have run a Powerdyne at 6lb in a Bronco as my first Supercharger, no bypass, but again lower boost and temps anyway. I prefer the positive displacement blowers as the boost comes-on much lower RPM and pulls you off the line in these heavier vehicles, heat is a concern. I think it is even more a concern with the 5.0 wedged into the engine bay. I am thinking I wont add boost till I can figure a way to cool the intake charge...................................am pretty sure the boost is building earlrier in RPM's without a bypass. I am at 5,400' and
If you have a KB 2.2 liter unit, it can run 8psi easily without big concerns over high IAT's. Running it hard over and over or at high speeds will make more heat, so for any combo keep that in mind. But for most normal usage, I'd swap the pulley and aim for 8psi at least. A lot of others have pushed smaller blowers(1.5-2.0 liters) to 8psi, and just above that they hit a wall of IAT temps and no power gains.

Mine is also a KB 2200, but I'll make it intercooled in the first step, on the stock engine. That I'll shoot for 8-10psi, trying to be a step below a final level with a bigger engine. I hope the blower pulley ends up around 3" and not much smaller, for better belt wrap and lifespan.
 


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Blown

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If you have a KB 2.2 liter unit, it can run 8psi easily without big concerns over high IAT's. Running it hard over and over or at high speeds will make more heat, so for any combo keep that in mind. But for most normal usage, I'd swap the pulley and aim for 8psi at least. A lot of others have pushed smaller blowers(1.5-2.0 liters) to 8psi, and just above that they hit a wall of IAT temps and no power gains.

Mine is also a KB 2200, but I'll make it intercooled in the first step, on the stock engine. That I'll shoot for 8-10psi, trying to be a step below a final level with a bigger engine. I hope the blower pulley ends up around 3" and not much smaller, for better belt wrap and lifespan.
Yup, my 5th blower build and 4th with positive displacement blower. I have run 12lbs of boost with meth injection for fun in the past. A 3.7” pulley – 1.76:1 = 8lbsof boost at sea level and 6.5lbs at 5,500”. If I head west I gain altitude and loose boost, about any other direction and I loose altitude and gain boost.

 




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