Does anyone know where to find some kind of high pressure throttle shaft seal for the stock Ls1 throttle body? Found out my seal is blowing tons of air out of it. I cant even find a replacement seal for it. Would another car have a seal that would fit?

 

Might have to pull it out and find something with a slightly smaller diameter online like McMaster? Or live with the boost leak. Compared to the amount of air the engine is eating, I'm betting it's in the noise.

 

it is letting out a ton of air. I have been trying to find something online, but cant seem to find anything that will work.
someone has to have had this same issue with boost

 

I think a "ton of air" is a mammoth exaggeration unless your TB shaft etc is so fucked it would be deemed scrap in the first place.

 

U could try flipping the old seal around

 

why not a new tb?

 

Haven't had 1 apart, but could there be space to put 2 seals in, back to back??

 

thank you for your useless comment.

I did think about this, I made an effort to try and improve the seal this weekend. It made it better but not totally sealed yet. I will be trying this tonight along with a few other ideas I think may help.

I would love to just go out and purchase a new 92mm or something but I cant justify spending the money on it if I can find a way to seal the shaft.

This is also a good idea, I'm not sure they would fit per say but to somehow bond the 2 together and maybe have them both flipped would work. The problem is finding them. I have come to find they are not sold seperatly.

 

Get a used stock one off of ebay for $50-$100, throw it on there and see how it does.

I try not to monkey around with throttle bodies too much, that blade can get set up wrong once and then you get a stuck throttle situation... not worth the risk in my opinion....would be a bummer if it got stuck while driving and you wreck the car, kill someone or blow the motor.

And to be honest, guys are going 8's on stock truck intakes and truck throttle bodies...no need to spend $300+ on an aftermarket throttle body unless your money tree is dropping hundos...

 

I appreciate the comment.
As much as I wish I did, there is no money tree here. thus the reason behind trying to seal my throttle body and not spending money on other throttle bodys. purchasing another stock unit when mine was perfectly fine doesnt make sense to me. I can see the truck units and drive by wire units holding much better because the shaft and entire unit is completly sealed. This is not the case with a drive by cable TB.
There is no way to setup the blade wrong, it goes in only one way and bolts in only one way. The only way it might become a problem is to do something to the seal that would cause so much friction it would make it sticky. The spring is for snap back, so it would have to be pretty sticky to not close. Besides in a stuck throttle situation the clutch goes in, the gear gets disingaged and car powered off. No need to go killing people around here.

I have had this thing apart 3 times now, and working on perhaps my final attempt of sealing it. I will find out tonight if it worked.

 

Measure the OD and ID with a dial caliper then get online and find you a seal should not be that hard plenty of industrial supply places (Grainger) sell seals by size.

 

Funny. I have a 78mm Accufab on my NA car. I chased a high idle FOREVER. First intermittent, that it got worse. After having most the car apart and swapping parts, I finally narrowed it down to the throttle shaft seal on the Accufab. Went back to stock and no more problems...

I smoke tested the car twice and never got any smoke from that area. Just a lot of tail chasing. I can't believe this issue is more prevalent, especially like you mentioned on an FI setup.

 

The results are in... I was able to seal it up. My final rendition of the shaft seal worked perfectly. High pressure no leaks. Best of all it cost me nothing. That was the goal!

--Success--

 

Any pics or explanation? Just in case this happens to someone else (like me).

 

Here it is...

I found out while doing multiple on and offs with my throttle body, stock unit using the edelbrock pro-flo it was barely covering the intake opening by maybe 1mm if that. Using the stock intake this would not be a problem, but somehting to keep in mind when using larger intakes. A plate was made to make up the difference on the intake manifold, but as far as the seal here it is.

I took the throttle body apart, and removed the rubber seal that the throttle shaft slides into. The way the seal is made makes sense for a naturally aspirated engine because it keeps the seal tight under vacume. unfortunatly under positive pressure the seal just lets air out because its not strong enough.
Here is a model I did to show the seal. I didnt take a picture of the factory seal so this will be a good representaion.
You can see how the sealing portion of rubber is bubbled outboard.



When on the shaft and under pressure this flap type rubber seal just spreads and lets air out



By flipping the seal it acts in a reverse idea. Under pressure the seal flap becomes pressed outboard and in tern making the seal tighter.



In addition to flipping the seal I added an O-ring that fit inside this flair type of indention to strengthen it.



I then added another smaller O-ring on top of that one that added another place of sealing.



I also added the same size O-ring on the opposite side creating 3 points of contact aiding in the sealing.









I then put the seal back in the throttle body reverse of the factory position and sealed it in with rtv silicone. The seal doesnt exactly fit tight reversed so the silicone is important to seal the outsides.



I let it dry over night before I reasembled the throttle body

 

Good deal. I bet you see another 0.5psi or so of boost depending on how much it was leaking before. Every little bit helps.

 

Good fix. I wonder if it will leak under vacuum now since you flipped it? Is there room to fit two seals that face opposite directions?

 

It might, but that is not any of my worry. I cant imagine it will pull much if any and surely nothing that will make any difference.

 

Even if it leaks under vacuum, I don't think it would matter since you're probably running speed density. So worst case scenario is you have to mess with idle fuel trims a little.