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S. Hardy
Dodge Dakota
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9/21/2003
17:47:10
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 Subject: V8 TB on a V6
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O.K. I know this subject is about beat to death, but I'm going to ask it anyways.
I have a 99 3.9 and I was thinking of swapping the 4.7 throttle body with the stock one.
I have read not to swap because you'll lose your low end torque.
So should I polish the stock or swap it for the larger throttle body?
If you've done the mod let me know what you think..
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wg34
Dodge Dakota
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9/21/2003
17:55:17
|  RE: V8 TB on a V6
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4.7 will not work,its a totally different type TB,you need one off a 5.2 or 5.9.
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J and J Auto
GenII
9/21/2003
17:59:22
| RE: V8 TB on a V6
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Message:
A 4.7 throttle body is completly diff,
Single barrel 62mm
You need a 96 or newer V8 body 318 or 360
Just bolt on do not polish cut air horns or remove
torque steps.
Bolt on As Is they flow 635 cfm just the way they
are.
The low end loss on most trucks is not very
noticeable and there is a lot more you will
gain versis a very small loss
A 48mm F&B flows 660
Larry
J&J Auto
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VegasOutkast
Dodge Dakota
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9/21/2003
18:14:03
| RE: V8 TB on a V6
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Message:
ok .... so I can put a '97 5.2/5.9l tb will bolt righ on in place of my stock '97? or will I need a new cable as well or something?
what is the size of the 5.2l tb ... 50mm or ?
And from what I see mentioned Larry, the 5.2/5.9l shouldnt make me lose enough low end to feel and if anything a F&B 48mm would make me lose more then the 5.2L 50mm since the 48mm flows more!
Thnx for your help as always!
I'd much rather pay $200 for a brand new 5.2L TB then $400 for and F&B if I can get away with it :)
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Burnt Out
Dodge Dakota
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9/21/2003
22:32:47
| RE: V8 TB on a V6
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Message:
I'll jump in here for Larry if he dosen't mind. The 50mm body is just a little too large for a stock 3.9. It causes too much loss in air velocity so the 48 is the better choice for the CFM requirements of you motor. You may notice a small amount of bottom end loss, but mid and top will improve.
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VegasOutkast
Dodge Dakota
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9/21/2003
22:45:03
| RE: V8 TB on a V6
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Message:
Ok, let me get your feedback then:
You said to much for a stock 3.9
What would constitute enough mods and what kinds for the 50mm to not be too much?
Thnx for your help!
Joe
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Burnt Out
Dodge Dakota
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9/22/2003
00:30:13
| RE: V8 TB on a V6
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CFM requirements for a normally aspirated engine are cubic in displacement,compression ratio, cam timing/lift/duration and expected max torque (say RPM) range of that combination. There is a forumla for calculating the required CFM rating. (Cubic inches/2)X (Max RPM/1728)X VF. The unknown factor is the volumetric effiency of your engine. That depends on the cam, compression, intake valve size, intake runner length, etc. Actually, the 635 CFM TB may be just a tad too large for a stock 3.9. Something around a 580-600 may be closer to the engine requirements. Any future mods may require greater CFM flow to make the conbination work.
Now don't think I'm an expert on this. I only learned this stuff by spending time in a dyno room with some of the old masters. As "Da Grump" told me once, "Shut up and watch boy, ya might learn something".
WHEW !
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Troy
Dodge Dakota
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9/22/2003
00:39:14
| RE: V8 TB on a V6
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Larry you said not to take those tourge steps off if you have a v6 but a couple of posts up u said to
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S. Hardy
Dodge Dakota
JOIN HERE
9/22/2003
19:25:22
|  RE: V8 TB on a V6
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Message:
Thanks Larry
I not sure where I got 4.7.
My brain must of been out to lunch.
I just did allot of searching through all the post and found allot of conflicting stuff.
I'm going to be searching the local junkyards to see if I can find one. First I want to replace my thermostat to 180 this week.
I've done a few of the easy cheap mods so far and the engine really seems to be responding to them. Seems to take it a day or two to adjust.
TPS sensor adjustment
Open air filter with K&N filter
Relocate AIT sensor
Famous S-Bolt mod.
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J and J Auto
GenII
9/22/2003
21:42:54
| RE: V8 TB on a V6
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Message:
A V8 Throttle Body has 50mm plates with 48mm
torque steps, if you mod this body and put it on
a V6 you will have no low end at all.
The aftermarket 46mm fastman and the 48mm F&B are
moded and designed so there is no low end loss
you will gain over the entire rpm range.
The V8 body loses a little velocity that's where
the low end loss comes in.
The V6's came with anything from 42mm to 46mm
removing the torque steps and air horns from these
smaller bodies helps a lot they just do not have
the volume of flow to lose velocity.
I am not a flow expert if you need concrete explanations
email Bruce Bridges over at F&B, I have had a lot of
conversations with him about this before I bought an
F&B 48mm
I have tried all 3
V8 good around $100 a cheap mod
Fastman better $250 with exchange modded stock body
F&B best $380 new
Larry
J&J Auto
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