So a while back I bought a used APR big port mani for my BT setup and it came with a 75mm drive by cable throttle body. After seeing the new SEM manifold and the 80mm TB it came with (nice price tag of only 175 for the TB) I decided to try to get an 80mm to fit on the APR. Unfortunatly the APR's bore was only 75mm but it had a small transition if you look on the inside where it got bigger. I decided to take the mani and TB to a friend and together we decided if we shave the outer edge of the mani back about 1/4" (after the throttle plate) the bore would be exactly 80mm. We used this really sweet machine that cuts with a brass wire and tons of little bitty archs. I must admit I was impressed. The cutting element never even touches the metal and the box in the picture below completly fills with water and all the cutting is done under water. Also the cut is smooth as glass, not one single burr. Tomorrow we will make a new throttle plate adapter to attach to the mani. Also my friend mentioned there is a "mud" type mixture you can add to the water that will completly smooth out all surfaces inside the object being cut and out (hmmm port polish anyone?)

stock TB vs. 80mm


checking the first cut 1/1000 of an inch) to make sure we were cutting straight


close up of 1/1000 of an inch cut of old throttle plate


notice the spool of brass wire. The machine automatically threads itself and continually feeds wire throughout the cutting process. One complete pass took 1hr 45min

 

thats some impressive stuff right thurrrrrrrr.....

the ingenuity of enthusiastic owners never ceases to amaze me, its great to see people trying things like this and experimenting!

Fair play, hats off to you

 

The TB is cheap since its from a Hemi and not a VW, that would be a $300+ TB if it was

 

That cartoon is depression Turbo...

 

lol yeah a bit... but not over here in Microsoft country ;o)

 

Left it last night on the machine over night for the finishing touches and looked at it this morning. Part looks great. Think I will dremel some of the edges just to give it a nice smooth transition instead of squared off so much. will post pics when I get home. On the down side didn't have time today to make the new plate. I did however draw up the plans on Solid Works and set a date for Friday to do the cutting...I know it doesn't seem like going from an 75mm bore to an 82.5 is worth the hassle but when you actually see the piece side by side to the new bore size it's very noticable.