Contour Enthusiasts Group Archives Forums Modifications 3.0L Duratec 4.6 Mustang TB for the Contour....70mm from MAC

I was looking for a bigger throttle body, and I found one on ebay this is made by MAC and is 70mm. I rougly estimated that the 3.0 could use a 67mm if I raised the throttle body size by 20%, the same amount that SVT raised the TB size from the normal 2.5L motor.

Has anyone done any conversion to a 4.6L TB?
Any advice and/or opinions?

warmonger

It's fairly simple.

You need to rotated the linkage 180
Enlarge the linkage throttle cable hole
Block off the bypass port
Cut off the throttle stop tab (for closed throttle)
Make a throttle stop (I just used heatshrink on the linkage)
Optimize the crap out of it.
Shim the gas pedal cable (~1/3") to take the slack out.

I'm sure I'm missing something...

Just a note, the 70mm TB I have from BBK didn't have a bypass port.

The after-market TBs I've noticed are "cammed" to open a bit quicker than the 65mm factory Ford ones, which are already faster than an SVT TB, so your throttle will be touchy as all heck. Not a whole lot you can do without welding in a bead to make the ramp angle change or perhaps weld on a new linkage arm perhaps. You're a resourceful guy warmonger; you'll figure it out. Nothing to tough...

It also may take a little while to get the throttle plate adjusted correctly once you rotate the linkage 180 degrees. A tip here is to keep the same orientation for the throttle plate relative to the TB housing (i.e. the top stays the top, front stays the front, etc) and don't rotate it with the bar/linkage.

A 70mm TB non-optimized without LIM secondaries will keep air speed up enough to blaze Kumho 712 235/40/17's on my SE 3 liter at around 2,500 RPM coming off a roll. I think I need to optimize it for better throttle response, what do you think? :rolleyes: :p I think I will just for fun...

Thanks guys, that is a great help. I bought it off of ebay last night and I hope I have it within the week I'd like to do that and the headers at the same time so I can 'feel' a difference.

warmonger

You'll also be pulling the UIM to port match it for the 70mm one IIRC, since the port is just barely big enough for the 65mm one. Have fun!

Even the DH UIM only had a 66.3mm opening.

Looks like more UIM work for you my friend...

Yeah, I need 3mm more diameter. I measured it (twice in two directions on different days) at 67mm. I guess I did have a really nice manifold when I got the car. Everything I measured on mine is pointing to Dual Honed, but I have an early 1999 SVT. I wonder why? Maybe they screwed up and ran it twice when they were honing it. I suppose I am lucky because that means the the inside where I can't get to is probably pretty good.

? Will the stock intake rubber tube(accordion) fit onto the 70mm TB, or even the 65mm?

Switching gears: Has anyone had any luck with that "spacer" to cure the area where the air deadheads into the manifold? I haven't seen much more talk about it and I wanted to know whether I should be developing something for it.

warmonger

For sure a "no" on the 70mm TB for the rubber thingie. The 70mm TB can swallow the SVT TB... The 65mm is a stretch, but does fit.

I have one idea about the splitter idea. Cut a slit or "v" into the "wall" of the manifold. Insert a flat or V shaped piece of sheet metal and weld in place... Of course, now I may be changing to the 3 liter upper anyway, so...

IIRC Kaiser tried spacers of a few different sizes and saw no difference in power.

My idea is to widen the sides on the UIM mouth to allow more room to divert to each side.

A diverter would be nice, but it would use up a large area of airflow space.
Maybe if done in conjuction with widening the sides as to not loose air flow area???

BTW - 99 & 00 SVT's had the DH UIM

I did a spacer, I never got around to splitting the air flow. I had to have one guy pull the throttle cable while I shifted on the dyno. It made 0 difference. A spacer however I don't know and then you have the whole attaching the throttle cable to contend with.