Modified Ford Racing 4.6 Mustang Throttle Body

[NC_Xplorer]

NO

There is a aftermarket TB by BBK that is made specifically for the OHV however.

Since I have a 4.0 OHV, the only option I have is to buy the BBK tb? Why wouldn't doing a similar mod to my stock tb work? Or should I but the BBK, and mod it?

 

[Fordexplorer140k]

The install ....

The removal and replacement of the throttle body was a straightforward less than 10 minute job ( see http://www.explorerforum.com/forums/showthread.php?t=139454&highlight=throttle+body ). Prior to removal the negative battery cable is disconnected and reconnected after the install.

Prior to the new throttle body install, I conducted several WOT 0 to 80 MPH runs so I would have a comparison to the same with the new throttle body.

Initial impressions on a road test and the 0 to 80 MPH runs were positive; I undeniably felt a difference in throttle response and acceleration at higher RPMs. There were no issues with the cruse control function.

The throttle response alone is worth doing the mod.

I shall be making a 1500 mile road trip ( to the Atlanta area ) this Friday; gas mileage will be evaluated. I plan to swap the modded throttle body with the stock one on one leg of the trip for a direct comparison.

Mileage data will be reported after the trip.

A jaunt to the dyno is also in the works; stay tuned.

NOTE: the pictures of the before and after of the shaft and screws were borrowed from the Sport Trac website. They are of a stock throttle body and are better quality than the ones I took.

I tried to put on my ford racing tb and it didmt bolt up so i did this mod myself in my step dads work shop, when mine was done it was A LOT smaller, it took me around 1 hour, I was hoping someone could tell me why my truck is slower than before during take off but around 2,000 RPMs i can feel a HUGE differents. today in my way to work it stalled out. please help.

 

[Jakee]

I tried to put on my ford racing tb and it didmt bolt up so i did this mod myself in my step dads work shop, when mine was done it was A LOT smaller, it took me around 1 hour, I was hoping someone could tell me why my truck is slower than before during take off but around 2,000 RPMs i can feel a HUGE differents. today in my way to work it stalled out. please help.

It could be because your PCM is expecting a certain amount of air to flow past the throttle body and now the calculation is wrong. I've done this mod and I did feel a difference in throttle response. I'm in no way saying it isn't a good MOD but I am saying that the PCM is tuned for the throttle body you have. Making small changes will not harm to much and while in closed loop (your 02 sensor are monitoring the oxygen level and feeding the info to the PCM so it can adjust the right fuel mixture) However, when you make big changes to the TB, the amount of air flowing past the TB will more than likely be different, and the adjustments being made by the PCM are greater than normal.

You may drive the truck around for a few more days and see if it get’s better. There is adaptive learning going on so if the PCM is constantly having to make adjustments to correct the expected air / fuel it will “learn” this and make the adjustment a permanent change in the KAM memory or “keep alive” memory. Sort of like a radio setting that you make that doesn’t go away until you disconnect the battery. This is why, when installing a new air intake, the instructions usually tell you to disconnect the battery. Same thing applies to the TB mod because it’s affecting the air flow. The proper and right thing to do is data log and monitor what the adjustment is and fix the tune in the PCM. The air flow past the TB setting should be made also if we want to be technically correct.

The easy thing, and first thing I would do, is make sure there isn’t a leak of some sort with the TB gasket.

 

[CDW6212R]

How did you get the TB to mount if the bolt pattern is different?

The TB size will not kill driveability like big things, it may be just a hair different though. The PCM's before 2002 have no learning abilities, that adaptive ability of the PCM began with the 2nd generation of OBDII PCM's, which was most 2002 models.

Unplugging the battery may help a hair to force the PCM back to a baseline of data, but prior to 2002 they cannot make big changes to learn shift patterns etc. I don't know more details of that adaptive system of the later PCM,s. I have not had the privilege yet.

First check your TPS sensor, what is the voltage at idle? Check it not running, idle through the WOT range. The voltage should be in the area of 1.0 volt at idle, and smoothly go to 4.5-5 volts. That is more likely causing the issues, that or a vacuum leak.

 

[Jakee]

I have a 2001 and have adaptive learning. I think you have something mixed up and I think there are different levels of adaptive which have progressively improved over the years.

That has me curious - I think I'll read up on the different versions now.

 

[CDW6212R]

I suspect it really started with the next generation of PCM. The 1st gen of OBDII doesn't really have anything useful like the later versions. Of course they are far better than OBDI(EECIV), but from what I have learned from Ford techs, these we have are nothing special.

 

[Jakee]

Read this quote...

The following information was taken directly from Mike Wesley’s article “EEC vs. EEC”.
“In the 1993 and older EECs, spark advance at WOT (Wide Open Throttle) was based purely on RPM. When you went
WOT, the EEC jumped to a separate spark function to give what Ford thought was the best spark curve. In the 94-95
cars, Ford made a major change to the spark calculations. The WOT spark function was deleted and now the car uses
the same spark tables for both part throttle and WOT spark calculations. The problem with this is the spark table is
based on RPM and Load. The formula for Load is basically the amount of incoming air, ratioed against how much one
cylinder can hold at standard pressure/density. You can think of Load as volumetric efficiency. The EEC uses the
MAF to determine Load. It is a direct measurement of how much air is entering the engine. You might be wondering
what the big deal about Load is. Well, since Load is used in the spark calculations, any change in Load will affect how
much advance you get. Since the EEC uses the MAF to determine Load, any change in the MAF will change the Load
calculation. Changes in the cam and anything that puts more air into the cylinders will also affect Load. Change the
flow characteristics and you change Load.

My way of thinking changes right now and forget what I said above about letting the PCM correct via Adaptive learning (there is no adaptive learning for the MAF Curve being wrong).....

If this mod is worthy then it changes air flow. If it doesn't change air flow then it is not worthy and has no gain, correct? I'll leave it to you to decide...But even when the PCM is correcting the air / fuel the timing table look up may be off because the load is off. This is all because the MAF curve actually changed but not in the tune. So in SOME cases, you may find a decrease in performance because the timing being run in the same RPM is now lower. This can all be corrected with a tune.

I hope this point is understood because it's the way it works.

 

[CDW6212R]

The MAF is key for the typical changes people make. For little things like the TB, the airflow change is very very minimal, and the MAF will read most of that change. That is basically correct for all of the typical small airflow changes(air cleaner, exhaust, TB).

Tuning the PCM is the best way to get the real most accurate tune for any new parts.

People get confused about what is going on, or what is a big change versus a little change. Prior to OBDII the list of small changes that the computer could handle was very short. OBDII can handle much much more without retuning the PCM. But for any EFI system, the best conclusion is always to retune the computer(PCM).

We have a good handle on this, but there are a continuous new group of enthusiasts that have never heard it.

I'm looking forward to getting my 347 in, but the bodywork needs to be first. I don't want my truck out of my hands for any great time, with an unknown person etc. I prefer to be the only one ever turning the key. The new engine technology available now is far far beyond 30 years ago. Back then you could barely make more than 1HP/CI at reasonable rpm's. Now you can actually reach 1.25HP/CI at 6000rpm, easily($4000). It costs money of course, but at least it's feasible now. Go back to the 70's and my friend built a 351C-4V based on an article. High compression and 7500rpm, it could reach 440HP. The same engine now with better heads and cam can see that power at 6000rpm, and way over 500HP above that. It's just more complicated now, we have more choices.

 

[Jakee]

By the way, here is how the PCM calculates load...

Load = VE = % cylinder filling =....

VE = Normalized Fill Volume / Theoretical Fill Volume

(Intake Charge Mass/min) / ((CID)*(ρSTP)*(RPM)*(0.5))

Where denisty of dry air (ρSTP) = 0.00004413 lbm/in3

For Example, a 346ci engine idling at 1.0lb/min airflow at 700rpm:

VE = (1.0) / ((346)*(0.00004413)*(700)*(0.5))
0.187265918
= 0.187 or 18.7% load

If we change (Intake Charge Mass/min) then we change load. If load changes, then a BUNCH of things that depend on load, as a value to look another value, now changes and CAN result in a loss of performance if the PCM is not retuned.

Further, no two engines are the same; therefore some may already have a messed up MAF curve and doing the slightest mod to air flow could rectify the need for a tune faster.

Okay, I'll stop now...sorry

 

[CDW6212R]

...
If we change (Intake Charge Mass/min) then we change load. If load changes, then a BUNCH of things that depend on load, as a value to look another value, now changes and CAN result in a loss of performance if the PCM is not retuned.
...

I agree, the tables and programming of the PCM are only ideal for a narrow engine combination. Changing anything affects it all. The cost of a flasher isn't cheap, but I think the cost of gasoline makes it cost effective for anyone.

The exhaust changes people make are neglected most of the time for tuning. So many people change parts of their exhaust, they change things a little at a time, or more than once. Never do we read that someone re-tuned the PCM for more than one of those changes. I'm going to get my new engine in and a good basic tune on it. Then I shall slowly replace the exhaust from back to front, not pushing the engine hard unless I have watched the A/F data. I hope to end up with a whole 3" exhaust(dual), and 1.75" headers. That will greatly affect the tuning needed.

You can swap throttle bodies regularly and not hurt much. People should open up the TB size a good 10mm or so for real power expectations. Don't do something like that alone and especially without further tuning plans. But the point is that a 75mm TB can work very well on a 4.0, bigger easily for big power goals.

 

[Fordexplorer140k]

It could be because your PCM is expecting a certain amount of air to flow past the throttle body and now the calculation is wrong. I've done this mod and I did feel a difference in throttle response. I'm in no way saying it isn't a good MOD but I am saying that the PCM is tuned for the throttle body you have. Making small changes will not harm to much and while in closed loop (your 02 sensor are monitoring the oxygen level and feeding the info to the PCM so it can adjust the right fuel mixture) However, when you make big changes to the TB, the amount of air flowing past the TB will more than likely be different, and the adjustments being made by the PCM are greater than normal.

You may drive the truck around for a few more days and see if it get’s better. There is adaptive learning going on so if the PCM is constantly having to make adjustments to correct the expected air / fuel it will “learn” this and make the adjustment a permanent change in the KAM memory or “keep alive” memory. Sort of like a radio setting that you make that doesn’t go away until you disconnect the battery. This is why, when installing a new air intake, the instructions usually tell you to disconnect the battery. Same thing applies to the TB mod because it’s affecting the air flow. The proper and right thing to do is data log and monitor what the adjustment is and fix the tune in the PCM. The air flow past the TB setting should be made also if we want to be technically correct.

The easy thing, and first thing I would do, is make sure there isn’t a leak of some sort with the TB gasket.

Alright, I am pretty sure I understand what your telling me. Hopefully yeah it does learn and self solve the problem. Its weird because the first time I drove it up the street and back after I bolted my TB back on, after the mod. I felt no difference. I thought nothing of it, then the next time I really got on the gas I noticed a huge differences and I was happy with my work. next time i drove, It was very hesitant to go, very jumping and un-smooth. Every since then I've had trouble when acceleration--only during take off, under 2500 RPMS---. Sometime when I accelerate the truck just stalls and turns off. I just don't understand, it just seems weird to me. In case anyone is wondering, take a look at the pictures al posted, then picture it half as small. That's how small mine it.

 

[CDW6212R]

It would be very wise to check the TPS voltage. Confirm that the signal going to the PCM is in the required range. That can greatly affect the engine running at all times.

 

[Fordexplorer140k]

How did you get the TB to mount if the bolt pattern is different?

The TB size will not kill driveability like big things, it may be just a hair different though. The PCM's before 2002 have no learning abilities, that adaptive ability of the PCM began with the 2nd generation of OBDII PCM's, which was most 2002 models.

Unplugging the battery may help a hair to force the PCM back to a baseline of data, but prior to 2002 they cannot make big changes to learn shift patterns etc. I don't know more details of that adaptive system of the later PCM,s. I have not had the privilege yet.

First check your TPS sensor, what is the voltage at idle? Check it not running, idle through the WOT range. The voltage should be in the area of 1.0 volt at idle, and smoothly go to 4.5-5 volts. That is more likely causing the issues, that or a vacuum leak.

I didnt, the ford racing TB didnt fit. So before i bolted my OEM TB back on i wanted to clean it well. I wanted to use a wire brush, with that in mind i went looking for one in my step dads little area and found the tool to port out my TB. So thats what i did, Its very small, maybe thats the problem. first my duma$$ buy's the wrong TB then i FU*k up the only one i have that works......

 

[Fordexplorer140k]

did work i should say, how do i do what you just posted?

 

[CDW6212R]

The TPS has three wires, a ground, a 5 volt power wire, and a signal wire which varies in voltage. I think it's the middle wire, but stick a paper clip into the connector from the back without disconnecting anything. The voltage should be near 1 volt at idle, and smoothly go up as you open the throttle. The 5 volts is a maximum, it really won't get that high.

If you still are after a TB, check on eBay. There used to be a seller who sold ported used TB's. Mine is a ported 4.6 Mustang version, basically no change. Go to a 70mm or keep the stock unit.

 

[Jakee]

I'm lost here. What exactly did you do that screwed up the stock tb?

 

[3ple8]

since we're talking about throttle bodies here, might i ask this simple question and pardon me if im a little new at this but, i was doing my research for my automotive class in the internet when i stumbled upon a throttle body spacer, i don't have that much money or knowledge, atleast not yet, to modify my whole throttle body. now my question is, by installing a throttle body spacer, would it (a) gain more hp as advertised? (b) gain more fuel mileage? i did install K&N short ram air intake married with a magnaflow catback exhaust for my engines' breathing...

thanks for your guy's replies in advance.

 

[CDW6212R]

An intake spacer(including the TB spacer) simply alters the intake path between the throttle blades and the valves. A shorter path or less restrictive intake is better for more power and higher rpm potential.

Adding a spacer to an otherwise complete designed engine does very little. It will not make more power, but the longer path will tweak the power curve downward. The power curve from a dyno would display that better, just slide the curve downward(to the left) towards the lower rpm's.

Example, a 1" spacer on a 302 intake will lower the power band by about 200rpm. It doesn't make more power, the previous power curve is just lowered slightly.

A throttle body spacer is typically not even 1" thick, so the affect on how far the power curve drops is less. You could figure about 100rpm per 1/2", that could be a good guess. People who know what it will do usually choose to do that for their truck for towing, due to the heavy weight. Don't do it unless you have money to burn, just like the "Tornado" and many other gimmicks. Regards,