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-   -   No More Stripped Turbo to TMIC Threads (

SeeeeeYa 11-26-2007 05:07 PM

No More Stripped Turbo to TMIC Threads
As anyone with a TMIC knows, especially those with WI, you have to take it off now and then. But even the first time it is installed it can be a hassle and according to the occasional post too many people either cross-thread or strip the threads on the turbo trying to get the TMIC attached.

It is almost always a pain. My procedure is to first insert the TMIC's throttle body exit into the TB boot, fully, and tighten it down securely. Next the TMIC must be levered into position so that, normally, the bolts that attach it to the turbo can be inserted through the TMIC and into the turbo's flange bolt holes. This has always been difficult, involving straining to hold the TMIC while gently trying to screw the bolt into the soft aluminum turbo flange without damaging the threads. I've done it many times, thankfully never ruining the threads but always close to it.

Not long ago while reading a thread in which stripped turbo bolt threads were mentioned I posted that I was going to change to studs when I installed my AVO380. This is what I ended up doing:

I got two bolts about 1 1/2 inch long, cut the heads off and reshaped the cut end so the threads were good. I got two lock-nuts and two regular nuts for the remaining, headless, bolts. I then threaded the cut end through the turbo bolt hole to a depth of 7/8 inch above the turbo, threaded the lock-nut onto the bottom and tightened it down (using the standard two nuts threaded together up top to hold the bolt/stud), and repeated for the other bolt hole.

At first I thought I'd thread the two bolts up through the turbo flange, but there was not enough clearance to do that. Then I figured I'd just get a couple of studs, and did, but I didn't feel they were as strong as having a nice nut underneath making SURE it wouldn't ever be pulled out (there is some thread clearance and it makes a bolt kind of 'loose.' The end result I described is perfect. Oh, and that gasket supplied by AVO with the turbo was a perfect addition to the Perrin's stock O-ring.

This modification made reinstalling my Perrin TMIC soooooo much easier it was amazing. I just pulled the TMIC over and onto the two projecting studs, pushed it down enough to get the nuts started, and tightened it down. Voila! Everyone should do it. In fact, turbos should come with similar hardware and instructions.

LittleBlueGT 11-26-2007 05:10 PM

My TMIC has never been hard at all to install, likely due to differences in UP design from your EL header to my non-EL header.

Thanks for the write-up. Now we need some pics!

boostsr20 11-26-2007 05:12 PM

Great Idea. I had to helicoil one on already. This is a better alternative.

SeeeeeYa 11-26-2007 05:22 PM

Pics will follow shortly.

BDII 11-26-2007 05:36 PM

uggggghhh my turbo side one is shot....

makes putting the TMIC back on a 40 minute exercise instead of a 20 minute ordeal.

I'm going FMIC.

SeeeeeYa 11-26-2007 05:56 PM


Originally Posted by BDII (Post 1524818)
uggggghhh my turbo side one is shot....

makes putting the TMIC back on a 40 minute exercise instead of a 20 minute ordeal.

I'm going FMIC.

Seriously, this mod takes very little time or effort. Even damaged threads can be accommodated. Once done there is no 'ordeal' again. It proceeds at the pace I described, minus the few moments ratcheting two nuts down securely. Period.

Trust me. I've had my TMIC off many more times than I can remember, for multiple reasons. It was always, as you describe, an ordeal. Never again. It is now a non-issue.

tommypenguin 11-26-2007 06:17 PM

Sounds like a another good idea from you Seeya. Pics or ban:)

PhilT 11-26-2007 07:56 PM

I helicoiled my AVO 420 when I installed it.

Why they don't do that when they make them is beyond me :spin:

SeeeeeYa 11-26-2007 08:03 PM

2 Attachment(s)

Originally Posted by tommypenguin (Post 1524942)
Sounds like a another good idea from you Seeya. Pics or ban:)

Wow, tough audience :lol:.

Best I could do at the moment. It's pretty self-explanatory but these give some idea. I thought of pics when I was doing it, but in the middle of what I was in the middle of it dropped off the edge.

AutoZone told me the size, an odd number, but I forget. I took the two stock bolts to my local Suby friend so that I could match them up and got some bolts and nuts out of his bolt and nut can.

As you can see it is utterly simple.

hogmeat 11-26-2007 09:23 PM

you could just be like Hogmeat - and not have to "leverage" or "pull" your IC down to your turbo. If you have to do that - your TB boot is not on right.
I've spent a few hours dealing wtih this, and wore out 1 boot (cracked a lip) figuring it out....but, you can get the boot to line up so that it just "falls" on your turbo. Nice n' flat.
I am usually 100x slower than others, and nothing ever goes right - so what took me 2 hours the 1st time, and 2 mins the 2nd time will take others a fraction of that.

tommypenguin 11-27-2007 01:06 AM

Looks solid to me. If I ever accidentally strip the turbo housing threads, I will do this instead of a retap.

LittleBlueGT 11-27-2007 11:42 AM


Originally Posted by hogmeat (Post 1525395)
you could just be like Hogmeat - and not have to "leverage" or "pull" your IC down to your turbo. If you have to do that - your TB boot is not on right.


Mine just falls into place, I can do it with one hand.

Merc6 03-27-2009 03:41 PM

My perrin doesn't just fall... I even tried losening the sleve to the tb side and still no luck of just faling on.

hogmeat 03-27-2009 07:55 PM

my original message still stands. Your alignment isn't right. It's not "loosening" it, it's rotating it. The thing is angled oddly, and whenever you make a SLIGHT adjustment, it is magnified 10x at the end where it bolts up. Try it again. and again. take your time. get pissed. it'll work.

qikslvr 03-28-2009 12:32 AM

I'm right there with ya. The turbo I just put on had stripped threads in it and I didn't even notice until we we're putting it on. I have a bolt in the back and a stud with a nut on the bottom in the front right now.
You can get studs from the autoparts store that fit also. You can use GM header studs that are m-8 and m-10's (i'll look for sure and try to get pics) if you have stripped them pretty good and need to tap them out to the next larger size. The studs will screw all the way down in and lock in just like UP studs. If this is done with a little threadlock the first time the TMIC comes off there will be no need for the bottom nuts. Slotting the hole in the TMIC will help save threads also.
Oh and I've had mine on and off of the stock turbo a hundred times and it used to just drop right in. After the turbo swap; not so much. I had to get a leg up and lean on it a little to get it bolted up the first time. I'll go back and mess with it, but I know I'll be tapping new bolt holes and stuff, so I'm in no hurry as long as it's holding for the moment:redface:.

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