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Old 03-01-2006, 04:40 PM   #1
Dragon02GT
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Default FOR ANYONE WITH THROTTLE BODY AND PLENUM QUESTONS

It seems to be a very popular question around here and many other 4.6L Stang forums,"What kind of Throttle Body and Intake Plenum is the best, and is the ACCUFAB really worth it?" Before I bought mine I did a lot of research. I found out a lot. The links below tell you everything you need to know. I have posted about this topic in several different threads in the past few days. I hope this helps you make you decision:

http://www.cnlperformance.com/plenum.html
http://www.modulardepot.com/?show=articlesdet&aid=38

So after looking at these sites, some conclusions to be made. Yes, the Accufab Plenum is the best, but recall the dyno numbers.
These are some numbers for the independent dyno runs you guys saw in the link: (Note all Plenums listed are using the Accufab 75mm TB)

Stock
RWHP 265.97
RWTQ 303.54

Accufab

RWHP 272.38 (+6.31)
RWTQ 310.42 (+6.88)

C&L
RWHP 271.13 (+5.16)
RWTQ 306.05 (+2.51)

Dragon
RWHP 270.69 (+4.72)
RWTQ 307.27 (+3.73)

Trick Flow
RWHP 270.19 (+4.22)
RWTQ 306.61 (+3.07)


So we can see it really doesn't make that much of a difference. But, how much do you want to spend? That should really be the deciding factor. The Accufab combo is the best, but it also runs about $400, the rest are about $300, depending on where you look, many sites offer the Accufab TB with the other plenums. Is the extra $100 really worth it to you, that's what you have to decide. It is not necessarily the HP you are getting fromt his upgarde anyway. It is the improved throllt response. And not only does it help with a great improvement in throttle response, it also helps smooth out your powerband.
Now when it comes to deciding what throttle body size to get, a lot of people around here will tell you that a N/A (naturally aspirated) car does not need a 75mm TB, and to just go with the 70mm. I disagree. The reason I posted the first hyperlink was to show everybody that the 75mm TB does make a difference in horsepower from the 70mm TB. Take for example the first test between the BBK 75mm TB and the Ford Racing 70mm TB, and the Accufab TB's with the Ford Racing TB (note: all tests with C&L Plenum)

Test 1, on a slightly modified Stang

FR 70mm
RWHP 267.99
RWTQ 308.28

BBK 75mm
RWHP 270.27 (+2.28)
RWTQ 312.65 (+4.37)

Test 2, on a different Mustang

Ford 70mm
RWHP 251.60
RWTQ 291.74

Accufab 70mm
RWHP 253.17 (+1.57)
RWTQ 294.50 (+2.76)

Accufab 75mm
RWHP 261.64 (+10.04)
RWTQ 304.32 (+12.58)

All the dyno charts can be found in the first link. The difference between the Accufab 75mm TB and the 70mm TB is +8.47 HP and +9.82 TQ. Why wouldn't you want the 75mm TB over the 70mm TB if they are the same price. With the Accufab combo they give you the choice of the 75 or 70mm TB with your purchase. Anyway, IMO you should get the most HP for your dollar, so if someone if willing to offer you a 70 or 75mm TB go with the 75mm. It shows at least a few HP gain every time. Even though everyone says you don't need it, it will not hurt you in any way, only help you get more HP. Isn't that why most of you are here, more HP for you $$$$$$$$. I am sure someone is going to disagree with me and say you don't need the 75mm unless you have a S/C or turbo, but before you do, just check out the numbers. More HP for the same price, do you really need to think twice about it?




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Old 03-01-2006, 04:45 PM   #2
starcam
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Default RE: FOR ANYONE WITH THROTTLE BODY AND PLENUM QUESTONS

Wonder what a ported stock tb/plenum would yield.
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Old 08-02-2006, 04:59 PM   #3
GTowner4life
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Default RE: FOR ANYONE WITH THROTTLE BODY AND PLENUM QUESTONS

I read a 75mm T/B will lean out your car up to 30% And because my car isa N/A wouldnt a 70mm T/B lean out the car less and still give you the same Throttle response? What about MPG?
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Old 11-22-2006, 01:18 AM   #4
NetChemica
 
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Default RE: FOR ANYONE WITH THROTTLE BODY AND PLENUM QUESTONS


Quote:
ORIGINAL: GTowner4life

I read a 75mm T/B will lean out your car up to 30% And because my car isa N/A wouldnt a 70mm T/B lean out the car less and still give you the same Throttle response? What about MPG?

Why would a bigger throttle body lean you out? Is there air sneaking in past the MAF sensor?
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Old 11-22-2006, 02:29 AM   #5
BLK03GT
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Default RE: FOR ANYONE WITH THROTTLE BODY AND PLENUM QUESTONS

I was hoping to buy a Accufab TB and Plenum very soon and was wondering where the best prices are???
Thanks
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Old 11-22-2006, 03:02 AM   #6
eventer289
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Default RE: FOR ANYONE WITH THROTTLE BODY AND PLENUM QUESTONS


Quote:
ORIGINAL: NetChemica


Quote:
ORIGINAL: GTowner4life

I read a 75mm T/B will lean out your car up to 30% And because my car isa N/A wouldnt a 70mm T/B lean out the car less and still give you the same Throttle response? What about MPG?

Why would a bigger throttle body lean you out? Is there air sneaking in past the MAF sensor?
Because the motor is able to take in more air than it could with a stock th/plenum. If the computer is not tuned to compensate, the car injects the same amount of fuel as it does stock, but with increased airflow, which in turn causes the a/f ration to lean out.
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Old 11-22-2006, 03:30 AM   #7
hot wheels
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Default RE: FOR ANYONE WITH THROTTLE BODY AND PLENUM QUESTONS

MPG? i still get a consistant 26mpg highway, don't really much care about city, too many stop signs.
Quote:
ORIGINAL: GTowner4life

I read a 75mm T/B will lean out your car up to 30% And because my car isa N/A wouldnt a 70mm T/B lean out the car less and still give you the same Throttle response? What about MPG?
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Old 10-01-2007, 03:41 PM   #8
Zanador
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Default RE: FOR ANYONE WITH THROTTLE BODY AND PLENUM QUESTONS

Quote:
ORIGINAL: eventer289


Quote:
ORIGINAL: NetChemica


Quote:
ORIGINAL: GTowner4life

I read a 75mm T/B will lean out your car up to 30% And because my car isa N/A wouldnt a 70mm T/B lean out the car less and still give you the same Throttle response? What about MPG?

Why would a bigger throttle body lean you out? Is there air sneaking in past the MAF sensor?
Because the motor is able to take in more air than it could with a stock th/plenum. If the computer is not tuned to compensate, the car injects the same amount of fuel as it does stock, but with increased airflow, which in turn causes the a/f ration to lean out.
I just want to say that if this was true, whenever people drove their cars on Cold days, they would be pinging like crazy. The whole Point of the MAF is to measure the temp and speed of the air coming past- while the TB/Plenum increases the amount of air coming in, that air is still coming past the MAF wire, and the computer can make adjustments. As long as there is not a leak after the MAF, the computer will be constantly changing fuel rate to make sure it is safe.

Obviously there are limitations to the stock tune, but basic bolt ons are not that limitation- it will be able to handle the TB/Plenum saftely just like it can handle a CAI, which basically does the same exact thing a Plenum/TB does.
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Old 10-01-2007, 03:52 PM   #9
nanaki
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Default RE: FOR ANYONE WITH THROTTLE BODY AND PLENUM QUESTONS

those are some really funny numbers. i put a TB/plenum on my car and had it done at the shop so we could see before and afters. i got 6RWHP with the accufab (7RWHP from the MAC, but the accufab was purdy and they gave it to me at cost). this was done when my car was already supercharged so should have been one of the best possible scenerios.
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Old 10-01-2007, 05:56 PM   #10
wwmost
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Default RE: FOR ANYONE WITH THROTTLE BODY AND PLENUM QUESTONS

i just got the c&l plenem and proffessional products tb 75mm for 200 bucks! combo on rpm outlet. but i do NOT recomend getting anything from them. the only reason i did is because i saw this deal. their customer service SUCKS and they sent my order to the wrong adress the first time. but im happy with it finally. it looks better then the stocker and gave me a little bit better throttle response. i dynoed 283 hp and 330 tq on a dynoject. mods: full exhaust, intake, tb plenem
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