Topic: 4.0 TB?

[smashcoast]

So i was thinking about getting Bounty Hunters little setup and Saw in the facts Fourbangers 62mm write up about cutting with the dremel.

My ? is  is that necessary? Will it improve that stup better?

[chardrc]

you don't have to do it. but if you don't there will be a "lip" at the manifold because the hole in the manifold will be smaller than the bore of the tb. there is a write up on how to do it around here somewhere.. (ill do a quick search)

edit:

found it this is one way to do it... has pic on second page
http://4bangerjp.com/forums/index.php/topic,7428.15.html

[dwtaylorpdx]

There is no point in doing the swap if you don't cut the lip out.

Dave

[sharpxmen]

if you don't enlarge the opening in the manifold is better to go with a plain 4.0L t/b as it matches the manifold. like Dave said, no point in going to the 62mm then and with a 4.0 will actually be better as it tapers down gradually and will accelerate smoother - if you flip a 4.0 t/b and start opening the butterfly slowly you'll see what i mean

[dwtaylorpdx]

My 4.0 stock TB required some relief of the hole as well,
I think there is a lot of slack in the diameter of the manifold hole.

Dave

[sharpxmen]

My 4.0 stock TB required some relief of the hole as well,
I think there is a lot of slack in the diameter of the manifold hole.

Dave

interesting, mine was right on the money (or at leasti don't recall doing anything but mind you was a long time ago so i might be wrong)

[Bounty Hunter]

There is one benefit to the 62mm throttle body if you decide not to open up the intake manifold to 62mm, and that is the large increase in throttle response.  The 62mm TB does not have the taper beneath the throttle plate as found in the stock 2.5L and 4.0L throttle bodies.  The removal of this taper allows air past the throttle plate immediately, for lighting quick throttle response.  A very noticeable improvement.

[Torch_Ind]

I have a 64mm tb and had to enlarge it to match also gasket matched the intake to the manifold.

[smashcoast]

There is one benefit to the 62mm throttle body if you decide not to open up the intake manifold to 62mm, and that is the large increase in throttle response.  The 62mm TB does not have the taper beneath the throttle plate as found in the stock 2.5L and 4.0L throttle bodies.  The removal of this taper allows air past the throttle plate immediately, for lighting quick throttle response.  A very noticeable improvement.

So are you saying that you need to open the manifold up?

[smashcoast]

Also I use all of the sensors from my old TB right? AIS and Map they will just fit right in?

[Bounty Hunter]

So are you saying that you need to open the manifold up?

I'm saying you should open your manifold up, but it's not necessary to still gain 'some' benefit from the 62mm TB.


Yes, you reuse all your sensors including the IAC housing (attached with 4 tamper-proof torx).

[smashcoast]

Ok. i will be contacting you soon.

[FourbangerYJ]

If you don't have a Dremmel type tool. A rotary rasp on a drill will work pretty fast on the Al. They can be had at the hardware store for a few bucks, they come in a few shapes.

[sharpxmen]

this is what i think Bounty is referring to about the throttle response (so Bounty please let me know if i got it right):
the 4.0L t/b is tapered down once past the butterfly - the purpose of that taper is to give more control on the acceleration at very low throttle opening, what it does is basically limit your throttle opening to only half of the t/b diameter (only the 1/2 of the butterfly that moves upwards will actually open, the lower half would follow the taper closely so until you reach about 1/4 opening it will not contribute at all (or very little). the 4.0 t/b is about 60mm at the top and around 55mm or so at the bottom. the 62mm t/b has the same diameter throughout (same with the bored out 4.0L t/b - it is 60mm top to bottom) - so w/o the taper your throttle will increase more between idle and 1/4 opening giving you more airflow per degree of rotation at the butterfly shaft.

imho, if you get the 62 you should enlarge the opening as at wot (or close to that) is where it will actually make a difference compared to the stock 4.0

[dwtaylorpdx]

One easy way to get the hole in the intake manifold
to the size you want is to find a hole saw that barely
fits through the Spacer. Then bolt the spacer on without
the throttle body and use the spacer as a guide to saw
the hole to size. I used a hole saw that actually took
about .005 out of the  spacer and it worked great,
matching hole clear through and the stock 4.0 TB engine side is
like .005 smaller which I think is acceptable for this purpose..

I followed up with a burr in a drill to take some obvious unequal
areas out and kind of dress the manifold to finish it off.

As I've posted about before what I noticed was not a power increase,
but more of a change in where power is at in the power band.
The 1" spacer I'm using moved the torque/HP band down about 600 RPM.
Which put me having nice pull off power at 2000 and flattening out around 5000.
Without the spacer it was higher in the power band. Engine is Hesco cammed B&B'd
and I'm running a paper filter but I have all the restrictive bits pulled out of the intake path.

Wish I'd had time to do some dyno work when I built
the motor I'd have tried the with and without to see.
Dave