Krambo Posted March 2, 2006 Report Share Posted March 2, 2006 Well, finally got the pics burned to disk. Here is a sample of what I did to the Radix to adapt the 90mm Corvette TB. First I elongated the bottom 2 mounting holes. I then used Mr Gasket material to cut out a rough home made gasket. (Summit Racing, $9.00) Further refinement to the gasket I then used a bead of silicone on both sides of the gasket and smoothed it out some to make for a leakproof seal. (blue silicone RTV liquid gasket, WalMart $2.50) I then dry mounted the TB to the Radix flange using the bottom 2 mounting holes. For me the two stock studs would not be long enough so I bought 2 stainless 6mm x 40mm bolts with washers (Home Depot, $3.50). While the TB was mounted, I drilled out the upper right mounting hole through the radix flange. I got lazy and drilled right through and utilized a 6mm x 50mm bolt with a nylon locking nut but you could tap threads and make it look cleaner (Home Depot, $2.50). I then tilted the butterfly and used a Sharpie to outline the material to remove on the flange. For me the butterfly would not open all the way making it difficult to mark, but I eventually got it. I also used this opportunity to mount the assembly with the gasket to do the same outlining on it. I only had a minor amount of material to remove on that. Now the fun part...have at it with the saber saw and the Dremel. Just like Big Tex, I used the saber saw to remove the majority of the material (went through 3 blades) and then went in with the Dremel to clean it up. I used a tungsten carbide bit in the Dremel with success only at lower speeds. If you spin it fast, the bit will clog up. Not a real big deal but does make for a longer time spent on the project. Looking at the area where I was with the Dremel, you can see how rough the interior of the J-tube is on the Radix. Kind of makes me want to take it to an extrude hone shop for some P&P. While I was at this point, I tapped a screw into the idle bypass area that needs to be filled in later with the JB Weld. The next post will contain more final pics...(dial-up is killing me ) Link to comment Share on other sites More sharing options...
Krambo Posted March 2, 2006 Author Report Share Posted March 2, 2006 Just another look at the un-polished ported flange. Again, note the screw. When I did the JB Weld, the screw was crutial in holding the epoxy in place while it cured. I had to do a few applications due to it dripping. I then had to grind down the drippings A look at the Corvette LS-2 TB in place. I tilted the butterfly for a good look at the flowpath. I was pleased on how smooth of a transition I was able to get with hand tools. Note the JB Weld filler in the top area. I didn't have time to clean it up and make all look pretty for ya all. If you need to make it pretty, you can easily spray paint the flange gray. I'll bet you wouldn't even know it was there. I used the Speartech harness for the TB and also the corresponding TAC module. Everything runs fine and does seem to be a little more touchy with throttle response. The only strange thing is that my Scan Gauge now reads 22% at idle (throttle position) and the TB makes a high pitch noise with key-on. I need to take final pics of the J-bolt application as that is missing in these pics. I couldn't find one in HD or Lowes to save my life. I ended up buying one at ACE Hardware on the internet. Maybe I will post more pics tomorrow...this damn dial-up took me over an hour to post this thread. Link to comment Share on other sites More sharing options...
mcwarren Posted March 2, 2006 Report Share Posted March 2, 2006 Great stuff! Thanks! Can't wait for your report on the finsihed project and performance results. Are you running a MAF? What are you planning for an intake air tube? Link to comment Share on other sites More sharing options...
Krambo Posted March 2, 2006 Author Report Share Posted March 2, 2006 I have a custom intake tube but I am running the stock one for now. It does line up just fine. Yes, I am still using a MAF. Been debating that one lately Link to comment Share on other sites More sharing options...
BigTex Posted March 2, 2006 Report Share Posted March 2, 2006 Great job Kevin and nice pictures. One note on the JB Weld: I used a machine screw with a much wider head, so there was less filler needed. Then I was worried about the stuff dripping or running like yours did. So After I had it filled in like I wanted, I covered the JBWeld in foil. The foil gave the JB Weld a "form" to keep its shape. I made sure the stuff was filled in a little thick, so I could scrape / sand it down after it had cured, which removed the outer layer of foil. Mine makes the same high pitch noise at key on for 10 seconds. I'd bet its making it after the motor is running too, but I can't hear it over the engine. I recall a post on corvetteforum about this same issue when a C5 guy moved over to a LS2 TB. I'm wondering if it has something to do with the voltage of the blade motor or a difference in the pulse width modulation it uses to control the motor. Excellent job. Link to comment Share on other sites More sharing options...
BigBlackAv Posted March 10, 2006 Report Share Posted March 10, 2006 Another version of the BigTex 90mm mod... http://www.performancetrucks.net/forums/sh...t=358691&page=3 Thanks BigTex! Link to comment Share on other sites More sharing options...
BigTex Posted April 2, 2006 Report Share Posted April 2, 2006 OK Kevin, its been a month since you started this post. How do you like it so far? What have you noticed from the 90mm mod? I changed so many things at one time that I can say what the effect of the 90mm mod was for me. Link to comment Share on other sites More sharing options...
zippy Posted April 2, 2006 Report Share Posted April 2, 2006 Did any of you get an SES light after the swap was done? Link to comment Share on other sites More sharing options...
Krambo Posted April 2, 2006 Author Report Share Posted April 2, 2006 The swap has been a nice addition. I did not touch any of the idle parameters and have not had any SES lights of any kind. She runs smooth. Being that the weather is still cool out, I haven't been able to compare any IAT logs before and after the swap without any bias. One thing is for sure though (based on an Autometer needle boost gauge), I now can hit 8.5 - 9psi with the same pulley. That is an increase of 1psi from the 78mm TB. I also pinned the crank pulley at the same time so maybe the pulley was slipping as well. (Check the How-To forum topic for specifics). Crank Pulley Pinning Within the next month or 2, I will be installing the new trans and hitting the dyno to dial in the meth, 90TB and possibly the SVO's. I will do a baseline pull and then do the injector swap and start spraying. I will post how much timing I was able to add with just the TB swap and then with the meth and TB. I am thinking an increase of 30-40RWHP is a realistic gain with the timing. Now, just for giggles, I could do a pull with the 78mm and then the 90 since it is a "reversable" mod Link to comment Share on other sites More sharing options...
Justin Lamanna Posted April 2, 2006 Report Share Posted April 2, 2006 Is the TAC a nessecary piece in getting the LS2 90mm TB to work with our trucks(2003 SSS)? I installed the TB and 90mm Fast intake this past week along with a bunch of other things. The computer has been tuned for all of them, last night we started it up for the first time. Runs but with reduced engine power. So i put the stock TB back on to see what would happen and it runs great. I bought the speartech adaptor and ported everything out the accept the intake and TB, so i guess i need the TAC module everyone is talkign about??? Suggestions? Link to comment Share on other sites More sharing options...
wkdivr Posted April 2, 2006 Report Share Posted April 2, 2006 Is the TAC a nessecary piece in getting the LS2 90mm TB to work with our trucks(2003 SSS)? I installed the TB and 90mm Fast intake this past week along with a bunch of other things. The computer has been tuned for all of them, last night we started it up for the first time. Runs but with reduced engine power. So i put the stock TB back on to see what would happen and it runs great. I bought the speartech adaptor and ported everything out the accept the intake and TB, so i guess i need the TAC module everyone is talkign about??? Suggestions? <{POST_SNAPBACK}> You need the TAC Module to "communicate" with the LS2 throttle body. I'm curious to see how that works with the KB blower. Link to comment Share on other sites More sharing options...
mwalls54 Posted April 3, 2006 Report Share Posted April 3, 2006 yes you do need the tac module from a 02 year. I really have been thinking of going with a 90mm Link to comment Share on other sites More sharing options...
vdrumright Posted October 28, 2006 Report Share Posted October 28, 2006 What is your impression of the 90 mm mod now that you have had it on for a while? Did you see lower IAT's? How about comments from anyone else that has done it? Was the final results worth the money? Link to comment Share on other sites More sharing options...
Krambo Posted October 29, 2006 Author Report Share Posted October 29, 2006 What is your impression of the 90 mm mod now that you have had it on for a while? Did you see lower IAT's? How about comments from anyone else that has done it? Was the final results worth the money? Other's will debate but I did not see the gains everyone was talking about. I attribute my increase in boost from the crank pinning and not the TB. If you get 10-15RWHP out of this mod, I'd say you are doing well. Is it worth the $500 minimum...not in my opinion. Again, others will debate but my dyno gains were minimal. Then there is the whole blade 100% TPS vs actual issue...that one is ongoing still. Link to comment Share on other sites More sharing options...
Krambo Posted February 6, 2009 Author Report Share Posted February 6, 2009 Bumping for a PM question Alot has changed since I did this post. You can now buy the J-tube from magnacharger that will accept the LS2 TB. There is now an "X-link" from Torquerush Performance that eliminates the need to swap out your TAC and buy an adaptor harness from Spreatech. When I did this mod the X-link wasn't available and the J-tubes were not readily available in a 90MM configuration for a few months later. Anyway, for a conversation, the Speartech / TAC swap with the 90 is bitched about for not letting the TB open a full 100%. For some reason my set-up seemed to open beyond the 90% that everyone complained about. Take a look at the last picture I posted and judge for yourself. Link to comment Share on other sites More sharing options...
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