Author Topic: Bored throttle body  (Read 330 times)

Offline Space Shuttle Commander

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Bored throttle body
« on: October 18, 2017, 07:42:36 AM »
So I had a few minutes to kill at work, so I logged into wrangler forum.

The first post was about bored throttle bodys.. Do they actually work

I have a boring bar for the Bridgeport, and could easily get to 63 mm. Is it worth my time though

Company's want 100 bucks for a bored throttle body, My guess is it would take 20 min to do


Worth a shot or leave it be ?
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Offline Mr. Easy

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Re: Bored throttle body
« Reply #1 on: October 18, 2017, 07:55:50 AM »
I would think it depends on the geometry of the mating surface of the intake manifold. If there is a step down between the throttle body and intake then I think any possible gains would be lost. If you worked the intake so it was as large as the throttle body with a smooth transition then maybe.

I'm thinking in regards to port matching intake manifold to heads, which should follow the same principles of airflow, turbulence etc...
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Offline MassJK

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Re: Bored throttle body
« Reply #2 on: October 18, 2017, 07:56:16 AM »
Same bore,stroke and cam. Wouldn't bother even CAI don't add all that much
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Offline MassJK

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Re: Bored throttle body
« Reply #3 on: October 18, 2017, 07:58:10 AM »
The radius at the inlet will have a bigger effect than the diameter.  Lots of fluid dynamic shit going on
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Offline Space Shuttle Commander

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Re: Bored throttle body
« Reply #4 on: October 18, 2017, 08:23:42 AM »
so I guess 63mm is the common size because that is the hole size in the intake manifold.

the hole in the throttle body is 58

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Online Gorilla_Skater

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Re: Bored throttle body
« Reply #5 on: October 18, 2017, 08:42:37 AM »
I've read that a bored throttle body will increase throttle response, but not much more. To see any power gains you have to make sure everything is flowing with a CAI and exhaust.

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Offline RedJeepster1

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Re: Bored throttle body
« Reply #6 on: October 18, 2017, 08:46:46 AM »
I was looking into this kind of stuff for a while when I was in college. You may find this link interesting.

http://www.fourwheeler.com/how-to/engine/154-0911-jeep-4-liter-engine-myth-busting-true-lies/

At the end of the day, just boring the throttle body likely won't do anything for you. On the other hand, 99+ intake manifold, bigger exhaust, ported head w/ polished exhaust ports, hotter spark and a cam can really liven up the 4.0. Throw in some 4 hole neon injectors and you can probably even get it to idle a little smother. Everything is set up to work together. When you change out one part and not another, you are likely just moving your bottle neck around until you do enough work to eliminate it entirely.
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Offline Space Shuttle Commander

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Re: Bored throttle body
« Reply #7 on: October 18, 2017, 09:01:51 AM »
Thanks for all the feedback,

I think ill table this thought for a while
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Offline JeepinMaxx

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Re: Bored throttle body
« Reply #8 on: October 18, 2017, 11:12:42 AM »
I was looking into this kind of stuff for a while when I was in college. You may find this link interesting.
http://www.fourwheeler.com/how-to/engine/154-0911-jeep-4-liter-engine-myth-busting-true-lies/

Great article!  looks like the exhaust mods are the best bang for the buck...  (my factory exhaust is rusting away so it's worth a shot)
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Offline Dollar Store petite pants

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Re: Bored throttle body
« Reply #9 on: October 18, 2017, 11:22:49 AM »
I have a bored TB, worked well and seemed to have a little more pep.  The snail that pushes lots of air through the bored TB helps even more.
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Offline King of the Hill

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Re: Bored throttle body
« Reply #10 on: October 19, 2017, 02:43:44 PM »
"My guess is it would take 20 min to do"

If I had a spare TB, and the tools to do it, I'd spend the 20 minutes and see what it feels like in the seat of the pants.

I definitely agree that you have to look at the entire system (intake, engine, exhaust) as a flow problem. 

I will say though, that with my 304 V-8, only changing the size of the jets in the 2BBL made a world of difference. 
I guess that the equivalent in a EFI motor would be bigger injectors or more fuel pressure.
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Online A new level

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Re: Bored throttle body
« Reply #11 on: October 19, 2017, 02:56:05 PM »
It's probably similar to port matching heads to headers. Smoother the flow the better. Only I have no idea if the ECU will adjust properly though.
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Re: Bored throttle body
« Reply #12 on: October 19, 2017, 02:58:09 PM »
Does that have an adjustable fuel pressure regulator?
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Offline MassJK

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Re: Bored throttle body
« Reply #13 on: October 19, 2017, 03:22:36 PM »
Don't forget just how bad the overall  flow path is on a 4oh
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Re: Bored throttle body
« Reply #14 on: October 19, 2017, 06:01:42 PM »
Don't forget just how bad the overall  flow path is on a 4oh

I haven't even touched one in almost 10 years  :eek:
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Offline Mr. Clean

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Re: Bored throttle body
« Reply #15 on: October 20, 2017, 10:06:40 AM »
I have a bored TB, worked well and seemed to have a little more pep.  The snail that pushes lots of air through the bored TB helps even more.

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