Topic: Intake Manifold Grinding

[mrcabinet]

Yeah, that nickname goes back almost 25 years, to when I ran the display shop for a well known Japanese knife company (starts with a K). The guys from corporate used to call me Mr. Display but, after designing and building a really trick cabinet for a trade show, one of the V.P.s came up to me and said "Orkay, you now be Meester Cabinet!". Its stuck with me ever since.

If you want to see what can be done with MDF cabinets, check out our website at www.kisscabinet.com.

I'm going to be drilling out the manifold today. I'll let you know how it works.

[sharpxmen]

Yeah, that nickname goes back almost 25 years, to when I ran the display shop for a well known Japanese knife company (starts with a K). The guys from corporate used to call me Mr. Display but, after designing and building a really trick cabinet for a trade show, one of the V.P.s came up to me and said "Orkay, you now be Meester Cabinet!". Its stuck with me ever since.

If you want to see what can be done with MDF cabinets, check out our website at www.kisscabinet.com.

I'm going to be drilling out the manifold today. I'll let you know how it works.

lol - pretty cool story

take some pics for us when you play with the holesaw and mdf - looking forward to see the result

[mrcabinet]

I did the drilling Saturday and all in all it went pretty well. It took about an hour and a half total, including the time to make the jig. The 2 3/8" hole saw was the right size to go with. Because of the run-out during the drilling, the hole came out at 61.78mm. Since the gasket measured 61.74 and the TB 61.89, it was just about perfect.

I ended up using a scrap piece of 5/8" MDF, which let me use the bolts without having to countersink the holes, and used the gasket as a template. The bolt holes were drilled slightly oversized so I could center it over the manifold opening.




Remember to take the bit out of the center of the hole saw!


The actual cutting took maybe two minutes, tops.


And here you have a nice round hole. A few swipes with a sanding drum in a Dremel cleaned it up and left it right at 62mm.


Would I do it again this way? You bet! But I don't know if it would be worth it to run out and buy a hole saw just for this.
I did remove the top two vacuum fittings and taped over the bottom two, then stuffed the holes with rags and gave them a good coating of grease for the shavings to stick to. If I were to do it again I think I'd stuff the holes and then use shaving cream to catch the debris (much easier clean up).

I put everything back together and the rig fired right up. No screaming idle, whistles or other issues. After punching it, idle speed drops to 1050 rpms and then drops right down to 750. I'm sure this will go away once the ECU re-learns itself. The throttle response is much crisper and low / midrange power shows a definite improvement. On the freeway it will hold 70 in fifth on a flat stretch and give a little increase now when I mash it to the floor. It still needs fourth on the uphill grades but will now actually pick up speed on those slopes. From what I've read, it should improve over time.

All in all, for less than a hundred bucks and an hour or two of your time, it is a great modification to do. BTW, Bounty Hunter is a great guy and you won't be disapointed if you get your TB from him.

Next up: Electric Fan!

[FourbangerYJ]

Nice. Glad it worked out. Looks clean.

[sharpxmen]

 
awesome, looks great - nice work 
thanks a lot for the pics

[Bounty Hunter]

Now that's the correct way to grind the intake, mine was much more butch

Good write up too.

[sharpxmen]

Now that's the correct way to grind the intake, mine was much more butch

Good write up too.

i am really jealous that i didn't come up with this 

[mrcabinet]

FYI, the manifold measured 55mm before drilling - the same size as the stock 4.0l TB at the bottom. The 2.5l TB measured 48mm at the bottom and the 62mm was, well, 62mm. That's a 22 1/2% increase over the 2.5l TB! I am thinking about adding a heavier return spring on the TB or gas pedal arm. Since it is more responsive now, bumps in the road that affect the right foot transfer to the throttle more noticeably now.

[mrcabinet]

Sharpxmen -

Don't feel bad. The only reason I thought of this is because it is exactly what we do in the field if we have to enlarge existing holes in cabinets.

[jfrabat]

I guess this means I now have to go out and buy me a new holesaw of the right size...  I already got the 62mm TB in place, so this would be a nice addition!  I am also thinking about taking out the TB and boring it smooth (mine is the Helix type) for better airflow...

[chrisfranklin]

It looks clean.  Let us know if it the mods helps.

[sharpxmen]

FYI, the manifold measured 55mm before drilling - the same size as the stock 4.0l TB at the bottom. The 2.5l TB measured 48mm at the bottom and the 62mm was, well, 62mm. That's a 22 1/2% increase over the 2.5l TB! I am thinking about adding a heavier return spring on the TB or gas pedal arm. Since it is more responsive now, bumps in the road that affect the right foot transfer to the throttle more noticeably now.

actually it's 66.48% increase: 48mm vs 62mm - the surface thru which the air goes thru is PI*Diameter^2/4 (EDIT: or PI*Radius^2 which is square radius times 3.14 - not sure if the way i posted that formula made sense in the first attempt) so directly proportional to the square of diameter.

Sharpxmen -

Don't feel bad. The only reason I thought of this is because it is exactly what we do in the field if we have to enlarge existing holes in cabinets.

not feeling bad at all, just being silly - like i said i was trying to figure out a way to use the holesaw, your solution was awesome (didn't occur to me to center it on the outside, i was looking for a way to use the center bit - I should send you one of those staples "that was easy" buttons as a gift for this)

[mrcabinet]

Well of course its 66.48% for the whole thing - I was just referring to the hole diameter at the bottom of the TB, and it was way too early for me to do math. 66.48 certainly sounds more impressive though!
I'll keep an eye out for that easy button.

[Bounty Hunter]

I am thinking about adding a heavier return spring on the TB or gas pedal arm. Since it is more responsive now, bumps in the road that affect the right foot transfer to the throttle more noticeably now.

The increase in throttle response reinforces the need to drive with only your toes on the throttle pedal, any more foot and you get a lot of throttle bounce.

[Bounty Hunter]

I am also thinking about taking out the TB and boring it smooth (mine is the Helix type) for better airflow...

I can take your helix spacer as partial trade towards a smooth 62mm spacer.  If it's of any help.