Mustang 4.6 throttle body on a 4.0 SOHC Explorer

[sloxploder]

Subscribing

 

[gijoecam]

After driving my truck more this afternoon, I have to re-examine my highlighted comment.

The difference that I feel is that the response to the throttle is indeed quicker; not a huge difference, just noticeable.

I decided to invite my son over to drive my truck. I told him nothing. He commented “what did you do to it this time?” I asked why and he said it felt a quicker when first giving it the gas. His comment in essence parrots mine.

I don't claim to be an engine tuning expert, and I don't play one on TV, but.....

Just intuitively, that would make sense. For the same throttle input from the pedal, the larger throttle body will allow more air to pass through it, and more air equals more gas which equals more power output. It doesn't necessarily mean that the engine is making any more power, it's simply getting more airflow for the same throttle input. So, yeah, it should feel like it's got a better throttle response.

But, (and there's always a but, isn't there?) I doubt that the increased bore will help the bottom line RWHP numbers unless the OEM 65mm TB was causing a restriction in the airflow to begin with, and the only time you'll see that is at WOT on a dyno, if at all.

If nothing else, an increase in throttle response can't be a bad thing. However if that's what you're going for, a modified throttle cable mount (the eccentric that the cable rides in on the throttle body) can accomplish the same thing.

There *could* be a downfall though..... try cracking the throttle while delicately perched on a tight trail, and you get more power than you were hoping for.... i.e. you somewhat compromise your ability to finely control the 'cracking' of the throttle..... it's all a trade-off.

-Joe

 

[aldive]

IThere *could* be a downfall though..... try cracking the throttle while delicately perched on a tight trail, and you get more power than you were hoping for.... i.e. you somewhat compromise your ability to finely control the 'cracking' of the throttle..... it's all a trade-off.

Joe, thanks for your insightful comments.

I seriously doubt that the above situation will ever apply to my Ecplorer; its strre ONLY.

I plan to visit the dyno later this week.

 

[aldive]

Today I switched computer tunes from the experimental economy 93 to my dyno tuned 93 in prep to go to the dyno next week.

Wow, what a difference, with the dyno tuned tue and this new TB, you can really feel a difference in acceleration.

 

[Afboy143]

im jealous

 

[bmxking5]

I'm wondering if 4.0s could use 5.0 TB's, there are 65mm stock.

I was wondering this too. I would love to test it out on mine, if I could get someone's stock TB for cheap or off ebay. I'd buy the BBK, but I can't justify spending the money on that when I know the motor is going to be replaced with atleast a 302 after the axle swap is done.

Oh yeah, really nice write-up Al. Can't wait to see the dyno numbers.

EDIT: If I KNEW that it would bolt up and work fine on mine (OHV) I'd be willing to buy a larger one made for the 5.0 if I also KNEW I was getting a 302. (Which I'm sure will be enough motor for me )

 

[95offroadx]

could you even use a 70mm tb from a 5.0 on a 4.0ohv? i know no one has done this yet, but if the stock 5.0 tb would work would the 70mm? someone try this!!!!!!!!!!!!!

 

[MONMIX]

hey Al, did you do the TPS "mod" with the instalation of the new TB ?

 

[gijoecam]

Completely unnecessary.... because of the way the PCM sees the ratch voltage and adjusts the idle accordingly, the TPS mod won't change anything on an OBD-II equipped vehicle. Basically, the computer learns that the closed throttle position is the lowest voltage it sees out of the TPS, regardless of whether it's .96V or 3.5V. The computer learns it and adjusts accordingly. Initially there may be a bit of a difference, but after the first drive cycle, I can guarantee there's nothing there.

-Joe

 

[CDW6212R]

Cool Joe, that would explain why OBDII vehicles don't ever complain about idle hunting like is common with performance EECIV engines. Basically the fix was always to play with the TPS, and the idle air bypass. Regards,

 

[aldive]

could you even use a 70mm tb from a 5.0 on a 4.0ohv? i know no one has done this yet, but if the stock 5.0 tb would work would the 70mm? someone try this!!!!!!!!!!!!!

Sure you could; just remove the 5.0 electronics and replace with the 4.0's.

 

[aldive]

hey Al, did you do the TPS "mod" with the instalation of the new TB ?

No; never saw any sense in it.

 

[MONMIX]

No; never saw any sense in it.

Truthfully it does. Mine was off signicicantly. A little better idle and a bit improved throttle responce. Weather or not the computer " wnet back to the way it was " I really cant say, but threre was un questionably a diferance, nothing tremdous or earth sahking though.

Your scan tool should be able to save you from back probing.

Just a thought man,,,,

 

[gijoecam]

Cool Joe, that would explain why OBDII vehicles don't ever complain about idle hunting like is common with performance EECIV engines. Basically the fix was always to play with the TPS, and the idle air bypass. Regards,

Indeed.... I explained what I found about the OBD-II/Ratch voltage from the TPS over in the TPS mod thread a while back.... I was told by a few people that I had to be wrong, of course, but given my understanding of how the ECU is programmed to interpret the TPS voltage, (actually, it was copied directly from the Ford service manual, so I didn't make this stuff up) there shouldn't be any possible way it could make a difference.

Instead of hijacking this thread, here's the page where I jumped into the fray (about 3/4 of the way down)
http://www.explorerforum.com/forums/showthread.php?t=79362&page=7&pp=40&highlight=TPS+mod

-Joe

 

[aldive]

No hijack at all, Joe, your input is welcomed.

I too agree with what you are saying. I feel there is no need for this "mod".

Thanks for bring it up again.

 

[gijoecam]

When's the dyno-day? The proof is in the pudding, right?

 

[aldive]

When's the dyno-day? The proof is in the pudding, right?

If all goes as planned, later this week.

 

[MONMIX]

Indeed.... I explained what I found about the OBD-II/Ratch voltage from the TPS over in the TPS mod thread a while back.... I was told by a few people that I had to be wrong, of course, but given my understanding of how the ECU is programmed to interpret the TPS voltage, (actually, it was copied directly from the Ford service manual, so I didn't make this stuff up) there shouldn't be any possible way it could make a difference.

Instead of hijacking this thread, here's the page where I jumped into the fray (about 3/4 of the way down)
http://www.explorerforum.com/forums/showthread.php?t=79362&page=7&pp=40&highlight=TPS+mod

-Joe

I just read over the link. My brain is tired, I got up at 5:AM this moring to fly back to Balto. and I actualy went back to work.
That being said, all the reading didnt exactaly sink in but I believe I understand where you are comming from.
Like " why .96 ? the ECM doent know .96 from two million six "
Is that what you are driving at ?
If so I can see your point.
Either way, mine is set and done.
Life goes on,,,,,,

 

[gijoecam]

Essentially.... yeah, you got the gist of it. It doesn't matter whether it's .96, .6, or 2.6, the PCM sees it and sets it as idle. If it suddenly drops from 2.6 to 1.6, the PCM says, "Hey, the new idle value is 1.6".... It always sees 5+ as being WOT, so it simply does a linear interpolation between the lowest (i.e.RATCH) voltage to the max voltage at WOT. As long as the resistance in the TPS is linear, the lowest point is irrelevant (within reason of course).

-Joe

 

[aldive]

When's the dyno-day? The proof is in the pudding, right?

Called the dyno facility today to set an appointment for Thursday; they are on vacation until next week. Looks like next Thursday is the day.