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Accufab TB/Plenum Results.

Old 06-30-2007, 07:41 PM
  #21  
cliffyk
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Default RE: Accufab TB/Plenum Results.

Well, they don't call 'em "slush-boxes" for nothin'... <g>...
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Old 06-30-2007, 09:16 PM
  #22  
undecided.steve
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Default RE: Accufab TB/Plenum Results.


ORIGINAL: cliffyk

[/align] [/align]For those with manual trannys it's a pretty sure boost--if you tune for it to. With your mods I'd expect another 7 to 12 HP, maybe 15, mostly by extending your powerband at higher revs.[/align] [/align]I don't really understand what's going on with the autos, except that the OEM (and subsequent) tunes for automatic transmissions are completely different animals. Autos have to be well-behaved and torquey at lower revs, and pulling strong, but not optimally, after the programmed shift point is largely irrelevant. [/align] [/align]This is why all other things being equal a manual transmission will beat an auto--it's the driver's (of the stick) ability to stay in a gear (or not) according to ALL conditions as opposed to letting the PCM or an array of pressure sensors make the decision...[/align]
[/quote]


I think you are spot on Cilff!
I suspect the power band is actually moved up higher and that's why the 5 speed guys feel a little more throttle response but the auto guys feel less because of where the auto shifts and the RPM range that automatics are generally driven in.

Like I said, I never floored it or drove it too hard because I suspected it was running lean and didn't want to harm the motor.
What really was bothersome though was the RPM hang. It was like driving with your foot on the gas and brake at the same time in a car with an automatic. You know how the automatic gets funky when you do that because it's confused.
That's how it was with the RPM hang.

Anyhow, a tune might have set things straight but I'm happy with the stock tune and don't want to mess with it.
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Old 07-01-2007, 12:57 PM
  #23  
ColinGT
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Default RE: Accufab TB/Plenum Results.

so i have an automatic, and i want that low end pull, so would this be a good or bad idea to get, cause it seems as if every1 has this mod
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Old 07-01-2007, 05:30 PM
  #24  
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Default RE: Accufab TB/Plenum Results.

Thanks for post, learnt a lot. Bit uneasy about installing the TB now, although Im manual. I had not heard that the voltage had to be adjustedto install a TB. I wouldnt know how to do that.
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Old 07-01-2007, 05:59 PM
  #25  
undecided.steve
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Default RE: Accufab TB/Plenum Results.


ORIGINAL: maxsixnine

Thanks for post, learnt a lot. Bit uneasy about installing the TB now, although Im manual. I had not heard that the voltage had to be adjusted to install a TB. I wouldnt know how to do that.
Technically, according to the Ford FSM, it doesn't need to be adjusted because the ECM will measure the baseline and compute from their.
It's easy to set to .98 volts though. The instructions are on Accufab's site.

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Old 07-01-2007, 06:18 PM
  #26  
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Default RE: Accufab TB/Plenum Results.


ORIGINAL: ColinGT

so i have an automatic, and i want that low end pull, so would this be a good or bad idea to get, cause it seems as if every1 has this mod
Many people have this mod and many people are happy with it.
There is no denying that.
I'm not one of them and I received a more than a few PM from people who experienced similar problems to the ones I had.
Mostly the idle hang problem, but others reported the same loss of low/midrange torque. The one thing in common, at least for the loss of torque problem seems to be that most with the problem have automatics. Also several people reported that the car got *better* a couple of weeks down the road. Others reported that they got the car tuned and it was perfect after the tune with power through out the range.

I would say if you are looking for low end pull and have an auto, save your money and get gears.
If you are looking at going FI or full bolt ons and / or intend to get a tune, go for it because it should be a good supporting mod for your other stuff.

Also several people told me that the FRPP 70mm unit solves the idle hang problem because of some kind of a hole in the blade that is correctly sized to eliminate the hang that other TB's may experience. Don't know if that's true, but I do know that Ford only makes a 70mm upgrade and not a 75 nor do they have an upgraded plenum which to me says something about Ford's take on this.
Just my 2 cents.

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Old 07-01-2007, 10:48 PM
  #27  
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Default RE: Accufab TB/Plenum Results.

the problem is the 4.6 really doesnt need a 75mm throttlebody im not sure about the exact specs but a 75mm tb. is meant for a larger cid. a 65mm tb will flow great untill you start adding cams and increasing your redline. i would go no bigger than 70mm and keep the torque where you need it. bigger is not always better a well planned out motor is way more fun to drive
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Old 07-01-2007, 11:55 PM
  #28  
nanaki
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Default RE: Accufab TB/Plenum Results.

75 or go home. the 75 is going to net more gains period. which actually isn't very many gains to begin with. you're just doing this mod for better throttle response. your butt dyno will tell you it added a lot of power, but a real dyno will say otherwise.
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Old 07-02-2007, 01:42 PM
  #29  
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Default RE: Accufab TB/Plenum Results.

ORIGINAL: cliffyk

ORIGINAL: meechuacon

The more I read about these tb/plenum problems, the more I don't want to do the mod.
[/align][/align]For those with manual trannys it's a pretty sure boost--if you tune for it to. With your mods I'd expect another 7 to 12 HP, maybe 15, mostly by extending your powerband at higher revs.[/align][/align]I don't really understand what's going on with the autos, except that the OEM (and subsequent) tunes for automatic transmissions are completely different animals. Autos have to be well-behaved and torquey at lower revs, and pulling strong, but not optimally, after the programmed shift point is largely irrelevant. [/align][/align]This is why all other things being equal a manual transmission will beat an auto--it's the driver's (of the stick) ability to stay in a gear (or not) according to ALL conditions as opposed to letting the PCM or an array of pressure sensors make the decision...[/align]
a manual is always better than an auto especially at a roll cause the autos take a second to downshift, and even then you gotta be in 4th, shut off O/D and floor it just to get to second, floor it in O/D and youll screw up the band and shift to third. but on the strip (since my auto is built) and on the street, manuals cant keep up. (though i do miss the "fun factor" of the stick) as for the TB and plenum combo... did you get an aftermarket plenum or stock? i never had these finish or drivability issues in my auto .. ??
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Old 07-02-2007, 01:57 PM
  #30  
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Default RE: Accufab TB/Plenum Results.

ORIGINAL: 03StangJL

the problem is the 4.6 really doesnt need a 75mm throttlebody im not sure about the exact specs but a 75mm tb. is meant for a larger cid. a 65mm tb will flow great untill you start adding cams and increasing your redline. i would go no bigger than 70mm and keep the torque where you need it. bigger is not always better a well planned out motor is way more fun to drive
the problem with modding and not getting a 75mm.. is the modding bug will bite you and you will probably end up F/I someday. seeing as how that is usually the case, the bigger tb will net gains better than a 70mm. set yourself up for success... so you dont have to work twice as hard. go 75mm.

compare it like this:
shorty headers (70mm tb)
Long tubes (75mm tb)
Stock (stock tb)

which would you prefer??

this applies to everything.. if you get headers why get shorties? youre there might as well do it right. same thing applies to the tb.. youre there might as well go 75 AND get a plenum
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