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1G Fixing the s90 throttle body

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At the end of the day for some of us it may seem like a stupid issue not worth the time or money to correct. The reality is there is a TON of guys using these with mafs who have no idea how bad these shitty things leak. In my case it was really really bad to the point were i couldnt even build boost. For the people that know we just stay away or go a different route. If we can find a simple fix i think its def worth fixing these things. If its just a matter of adding a seal to the tps side then I think its well worth it. More to come.... still waiting to hear back from the bearing company
 
Steve at throttlebodies.com might be able to save you guys some time on this.....maybe. I know he bores out the seats on some of the units he does to accept better/larger diameter seals for higher boost........maybe hes done one of these and can offer some info on parts that work for the S90 efforts. Worth a phone call/text at the least, hes always seemed to be willing to help and share info. 405 314 4070
Steve wasnt interested in the issue as he deals with the oem specifically....
 
I can help you out on this issue. I can also give you the size of the seal which it only uses one instead of 2 like the stock units. I definitely notice better overall driveability when I upgraded to metal cased seals in my oem throttle bodies and my 74mm s90! The size for the seal is 12x18x03
 
Took me some time but it works, Its a simple fix but it held 50psi with only a tiny tiny leak. That to me is a win. The only thing I'm going to change is the depth of the o-ring groove. I made it too deep, I probably could completely seal it off that way.

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I found the leak to be on the cable side hard to fix, the TPS side has an easy fix for both the 70 and 74mm models that was discussed on the LINK forums. The issue for me was the cross shaft come through the tbody housing where there is no immediate seal but just the bearing. The OD of the bearing is pretty sealed and so is the shaft going through the bearing....but the area where the balls ride in the races are not sealed at all which is where the air leaks. I for the life of me can't remember exactly what I did but it involved putting in a seal pre bearing so it would be sealed.
 
It was bugging me so much I pulled mine apart and made a video.

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Do you think over time the bearing will wear through the gasket and cause it to leak? There were so many factors in designing the part. The spring washer allows for a little wiggle room to allow for throttle plate placment. The way we designed it allows the viton oring to move with the throttle shaft and therefore wont become damaged over time. I may incorporate this idea in some way in addition to my new part. To make it bomb proof.
 
From an engineering perspective that is not an ideal seal design compared to a lip seal with a spring around it. However there is so little movement so I feel comfortable it will last. That thing at max only turns 90 degrees and it operates at a very slow rpm (you know ankle angle speed) so there isn't any real wear. Yes over 300K miles I'm sure it will wear out like any other seal. Considering most DSM can't make it out of the driveway I am not too worried. Just remember if that seal does fail what is the consequence..... a tiny boost leak, it's not like you'll lose control of the car wreck and die.

Is it the best, NO, will it work? YES, did it cost me anything? NO
 
From an engineering perspective that is not an ideal seal design compared to a lip seal with a spring around it. However there is so little movement so I feel comfortable it will last. That thing at max only turns 90 degrees and it operates at a very slow rpm (you know ankle angle speed) so there isn't any real wear. Yes over 300K miles I'm sure it will wear out like any other seal. Considering most DSM can't make it out of the driveway I am not too worried. Just remember if that seal does fail what is the consequence..... a tiny boost leak, it's not like you'll lose control of the car wreck and die.

Is it the best, NO, will it work? YES, did it cost me anything? NO
Whatever works man
 
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