BigTex Posted February 9, 2006 Report Share Posted February 9, 2006 I've had numerous people asking me for information, so here goes: I cut out a paper template using the back of the TB as a guide. I used a SSR 90mm TB, so it has a little different shape than the vette version. This pic shows roughly how the 90mm mates up to the 78mm flange. Here is an overview of what needs to happen: The tube behind the flange is plenty large enough to support a 90mm opening. I removed all three original TB studs from the flange. The lower two holes I reused with longer bolts, the top one doesn't get used. The yellow circle is roughly where I tapped another bolt hole. I colored in the area that I needed to remove with a blue marker (shown outlined in red in this picture). The area shaded green needs to be filled in as the 90mm doesn't have any idle airflow bypass needs. I used a large machine screw and JBWeld for this. I used a plain jigsaw with a metal blade to make the main cut. I removed the lower guide from the saw and handled it like a mini sawsall, so I wouldn't be beating up the surface of the flange. At this point, I used a rotary tool to finish shaping the opening in the flange and to smooth it all out. I have a large flex shaft version of the dremel that works wonders. The plain dremel should work fine too. Now to the TB itself. The lower two holes are just a bit wide to fit over the 78mm flanges original lower studs. So I took a small round file and elongated the lower holes about 1/4" as shown below. This takes care of 2 holes and also firmly sets the position of the TB in relation to the flange. I created a third hole in the flange as marked in yellow above. That just leaves one hole to be secured. Now from the rear, we can see the 90mm TB leaves one of its bolt holes sticking out past one edge of the stock flange. Instead of making a major alteration to the flange, I chose to use a "J" bolt in the 4th hole. That bolt basically is secured by reaching behind the rear of the flange. I trimmed the extra length off the bolt so it doesn't stick out farther than needed. I made a small depression in the back of the flange with a drill bit for the J bolt. This basically makes a seat for the bolt so it always gets secured in the same location and doesn't move. From here you can see the mostly completed 90mm mod from the rear. The J bolt is hidden behind the motor and can't be seen. On the left you can see the rear of the flush mount stud I used for the other top bolt hole. This J bolt is very firmly secured, so don't let that scare you off. Step not shown is filling in the open spot on the flange. I didn't like the idea of filling that whole area in with JBWeld. So I found a large headed machine screw that just fit inside that recess. I tapped the screw and made sure it went just past flush. Now filling in the rest of the thing with JBweld was easier. With the screw taking up most of the space, I didn't have to use as much filler and know the JBWeld has a more secure hold. Physically the JBweld came out gray in color. It stands out more on my polished flange, but would probably match the color of a painted radix pretty well. You can see this area with JBWeld in the picture below, barely sticking out above the top of the TB. I'm completely happy with how well the JBweld part of this worked out. Why do this mod? It works well, its cheap, you can do it yourself, and its reversible. By adding the top stud back to the flange, you can remount a 78mm TB if you'd like. Link to comment Share on other sites More sharing options...
misterp Posted February 9, 2006 Report Share Posted February 9, 2006 Awesome. Mr. P. Link to comment Share on other sites More sharing options...
pnblwzd Posted February 9, 2006 Report Share Posted February 9, 2006 Sure looks impressive. How much is gained wtih this mod? Very nice write-up, too! J Link to comment Share on other sites More sharing options...
detjoe Posted February 9, 2006 Report Share Posted February 9, 2006 great info, thanks for posting for us. you got this yet FuelSlut?? Link to comment Share on other sites More sharing options...
FuelSlut Posted February 9, 2006 Report Share Posted February 9, 2006 im on it as we speak, parts said it should take a few hours to get the tac module, speartech should have the harness out sooner or later? im not sure how they are with shipping.thanks Bix Tex... your the manBTW how much diff. is the vette t/b? Link to comment Share on other sites More sharing options...
FuelSlut Posted February 9, 2006 Report Share Posted February 9, 2006 btw whatd you use for a gasket? Link to comment Share on other sites More sharing options...
Krambo Posted February 9, 2006 Report Share Posted February 9, 2006 ...Just how I pictured it Richard. What, no welding ;) ...One addition that I was going to try. Can the 90 TB be mounted so that the blade can be manually tilted so that a marker can be used to scribe a line to cut (instead of the template)? Then remove the 90 and cut. Did you use a gasket or did you use the gasket replacment (loctite) that is used on the other parts of the blower? One hell of a write-up. I expect nothing less, your innovation on these boards has been a driving force for many. Link to comment Share on other sites More sharing options...
FuelSlut Posted February 9, 2006 Report Share Posted February 9, 2006 One hell of a write-up. I expect nothing less, your innovation on these boards has been a driving force for many. <{POST_SNAPBACK}> Link to comment Share on other sites More sharing options...
BigTex Posted February 9, 2006 Author Report Share Posted February 9, 2006 Thanks guys. I bought some gasket material and used the TB as a template to create a gasket. Pretty easy. Kevin - I was able to mount the 90 without even opening the flange hole. When the blade opens, by the time it hits the flange its already narrow enough to pass through the 78mm hole. Link to comment Share on other sites More sharing options...
FuelSlut Posted February 9, 2006 Report Share Posted February 9, 2006 what do you think would look better/cleaner? excess gasket or the exposed j/b welded port? just wondering... opinions? thanks again Big Tex... and again and again and again... Link to comment Share on other sites More sharing options...
BigTex Posted February 9, 2006 Author Report Share Posted February 9, 2006 You could take some 1/4" thick aluminum and cut out a hybrid throttle body spacer. Blend the shape of the flange with the shape of the 90mm TB. Give it a 90mm opening to match. Use a gasket on each side. Then you could completely skip the JBWeld step because this spacer would seal it up. Link to comment Share on other sites More sharing options...
FuelSlut Posted February 10, 2006 Report Share Posted February 10, 2006 Link to comment Share on other sites More sharing options...
vdrumright Posted February 10, 2006 Report Share Posted February 10, 2006 I just scored a LS2 SSR 90mm Throttle Body for $75.00... Link to comment Share on other sites More sharing options...
FuelSlut Posted February 10, 2006 Report Share Posted February 10, 2006 bastard! hey vdrumright... wanna do them together? Link to comment Share on other sites More sharing options...
vdrumright Posted February 10, 2006 Report Share Posted February 10, 2006 bastard! hey vdrumright... wanna do them together? <{POST_SNAPBACK}> Wanna make it a get together at Zippys? I still have more parts to track down. Do the 03's need the tac module? Link to comment Share on other sites More sharing options...
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