I performed the test on the fast 92mm throttle body and it does not leak. I can post a video in a few days (phone is foobar at the moment).

The point of this post to begin with is I have a cam the overlaps decently (around 9) and the expected vacuum from compcams is 15.

As pointed out by plenty in this post, my problem may very well be elsewhere but obviously compounded by the leak on this throttle body.

We have more than one post in here reporting Nick Williams tb's leak at the shaft. We have a stock and my new FAST 92mm tb showing that it does not leak.

I think its safe to say it should not leak and blanketing my problem to acceptable loss is not only unhelpful but reflects poorly on the designer for not even offering to look at it.

Thank you all for posting its been very informative and helpful in solving this leak issue.

For those that still believe acceptable air leak in a throttle body is ok, please pm me so I can sell you mine (has less than 1000 miles on it).

 

Sorry dude on my buying it, already running NW102.

As far as estimating your leak rate, CFM is cubic feet per minute...eyeball the bubbles relative to a 1ft cube.

IMO youre test at best tells you what to test. To give a little more confidence that this leak is your problem why not do a propane test, hit with brake cleaner, or maybe even temporarily goop the shaft with some kind of sealant or vacuum grease. Havent looked closely on what it takes to replace the o ring, but maybe try that? Did you install the 92 and fix your problem?

As ive said I think you might be chasing a red herring here, but who knows maybe that little leak really is your issue. I doubt youll have any trouble selling it if you put it in the classifieds. GL with your leak, they sure suck sometimes.

 

Thanks for the visual measurement, that makes sense! Right now the power train is completely removed from the car (gotta love max jax ). I did try carb starter before but not on the throttle body, was trying like the vacuum lines, around the intake, etc. Just didn't place the thought to it being this.

It looks like the shaft is pressed into the throttle body along with the bearing assembly but I am no expert on this. I was hoping that Nick would have offered some kind of service to check it out but apparently that's not going to happen.

Once I get this back up and running I will definitely post the vacuum results at idle (good or bad). Thank you for adding to this post, I appreciate it!

 

I wonder if the o-ring that seals the shaft comes lubricated? Seems like if it was put together dry, over time it would start to wear and leak as you have seen. Replace it with a viton o-ring (resists degradation due to harsh chemicals, oils, etc.) and grease it up prior to assembly. Might be a relatively easy fix.

 

This very well may be the problem, if so maybe all of them were like that because right now I am not the only one with the leak. Great suggestion!

 

I really can't help on sizing, maybe remove your "stock" one if you can to take your measurements from. but this place has pretty much anything you could ever need. Insanely fast shipping too..

http://www.mcmaster.com/#o-rings/=lw0dcz

Click on "Viton Fluoroelastomer O-rings" top/center

 

I reread what nick posted and I think the oring may actually be the one that seals the bearing, like the ones built into it? I dont think most sealed bearings are user serviceable. Anyway I still think you should worry about other things for the time being and this if it shows to be a problem in future testing when running. Life is short, have a beer.

 

OP, imo a leak is just that & a TB should not leak.
Hope you get it sorted.....

NW! not impressed by your very short, blunt, replies & lack of acceptance of a possible problem with your product.

A lot on here buy your gear, You could learn some better customer relations from a certain Texas sponsor, a little support will sure help your business grow.

 

if its the type of sealed bearings I'm thinking of, the seal just pops into a groove on the outer race of the bearing. it's easily removed with a little finesse from a pick...I've taken many bearings apart and repacked them in this way. it seals the ball bearings from dirt etc. but wouldn't seal the tb itself. what you need is some sort of seal between the OD of the tb shaft and the inner race of the bearing it passes through. if a feature like that doesn't exist, you could take out the shaft and turn an o-ring groove into it in a location where it would be contacting the inner race of the bearing.

 

My NW 102 DBW also leaks in 2 spots. I tested it with a snap on smoke machine. Is it right? NO. However it doesn't seem to affect anything and it is pretty.

 

interesting.

 

Just for the record I have a leaky blade shaft on my NW 92mm TB like the OP posted. I puffed 2 cigars through the hoses trying to find leaks.

 

That is hilarious!! Need to try that next time. Did you do anything about the leak? Has it caused you any issues?

 

Since I am apparently way to detail oriented, I decided to order up another fast 92 just to see if maybe I happened to get a good one.

The second brand new FAST 92 tb did leak! My first one didn't but maybe if I wear it in (once im up and driving again) it will. I am a few weeks before I will be driving again to test this.

If I see a leak with the first FAST 92 tb I am definitely going to try the viton suggestion as that really makes sense.

So most likely the majority of these posts are correct that this won't cause an issue but at what point did the aftermarket industry say "Oh my design leaks, its ok guys no for real its ok."?

If stock doesn't leak then why should aftermarket be less of a product? Thoughts?

 

out of curiosity have you tested a stock tb? I have trouble believing high dollar aftermarket tb's would leak whereas the stocker would not

 

Excellent point, I personally have not tested a stock TB but one of the earlier posts from another ls1 member said he had performed the more expensive smoke test on both the NW and stock. Stock did not leak for him.

If I had one handy I would definitely try it but at this point I can't mount up a stock TB either because of my fast 102mm intake.

Could put a plate on one and seal up the back and perform the test that way too I suppose.

Anyone else have a stock TB test like this or the smoke test done?

 

I'd offer to do it but I just sold mine, interested in results though.

It'd be nice to see exploded diagrams of the NW, FAST, and stock tb. Might help with troubleshooting these leaks, I'll see if I can find some.

 

looking at the stock TB, i can't imagine they are excluded from this leak. The bearing/shaft area seems to be pretty similar. And i know nobody wants to hear this, but if the car was tuned with this leak, its probably fine. Its small so yeah its unmetered but it was accounted for in the tune.

 

Anyone find anymore info on this situation? Mine leaks like a ***** at 25 psi really does not seem acceptable a leak is bigger leak under boost

 

I ended up just going with the fast 92 even though that did not solve my overall issues. It helped a little but not enough to meet the cams specs.