Gas tank venting - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to   Members

Race Prep Miata race-only chat.
Sponsored by:
Sponsored by:

LinkBack Thread Tools Search this Thread
Old 11-02-2013, 12:10 AM   #21
iTrader: (11)
sixshooter's Avatar
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,902
Total Cats: 1,592

FWIW, I took the line from where the canister was back down the frame rail towards the diff and let it VTA back there.
sixshooter is online now   Reply With Quote
Old 11-07-2013, 12:22 AM   #22
Senior Member
iTrader: (8)
paNX2K&SE-R's Avatar
Join Date: Dec 2007
Location: Mocksville, NC
Posts: 685
Total Cats: 11

Thanks Six. I was over thinking things before, I'm going to keep everything on top of the tank stock. I haven't decided whether or not to keep the charcoal canister but either way I'm going to run a line up near the diff and VTA (with a filter just in case).
paNX2K&SE-R is offline   Reply With Quote
Old 11-08-2013, 04:31 AM   #23
Join Date: Nov 2007
Posts: 23
Total Cats: 0

Originally Posted by ZX-Tex View Post
So, the answer here could be to simply plumb the rollover valve directly into the TPCV, then vent that (through a filter) via a hose to some safe point under the car.
That is what I did on my last race car and never had issues or got questioned during tech.
Ningai is offline   Reply With Quote
Old 10-09-2015, 02:39 PM   #24
Junior Member
Join Date: Jan 2013
Posts: 61
Total Cats: 0

Sorry to bring this back from the dead but I'm looking to mess with this soon. I've attached a diagram of the EVAP system for the shop manual. I'm not sure why you would want to connect the TPCV with the Rollover Valve as people were saying earlier because they're already connected up at the filler neck.

Seems to me that the best course of action would be to disconnect the line before it goes into the TPCV (#7) and run a hose to a filter under the car. Then you could remove the TPCV, charcoal canister, catch tank (in the engine bay), etc. You guys see any problems with that?
Attached Thumbnails
Gas tank venting-miata-evap.jpg  
jamesr242 is offline   Reply With Quote
Old 10-10-2016, 07:20 PM   #25
Senior Member
iTrader: (3)
Join Date: Dec 2008
Location: KY
Posts: 713
Total Cats: 51

I deleted all the evap/charcoal stuff on my 99 a few weeks ago and just ran the car on track for the first time this weekend. I started off with the tee'd lines as shown in the original post, along with the spring removed from the stock gas cap. Stock gas cap normally allows flow during vacuum but no flow during positive pressure. Removing the spring allows gas pressure (AND liquid fuel) to escape through the cap.

I got black flagged twice because the corner workers said my car was "dumping fuel out of the trunk." Quickly realized it was dumping out of the gas cap, then running down through the drain hole beside the gas cap. "Quickly realized" because when the gas cap was removed and turned upside down, fuel poured out. This was with roughly 1/4 tank. First I tried un-doing the tee setup and just running a hose down to the frame rail, but I still got black flagged again. Finally I switched to an unmodified NA gas cap (one of the corner workers was nice enough to trade me for the weekend) and had no problems for the rest of the weekend.

What jamesr242 posted above is exactly what I ended up with.
jpreston is offline   Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
Someone help me with AE ihiryu MEGAsquirt 33 10-08-2015 05:56 PM
Lots of stuff from my NA BRG partout. Corifto Miata parts for sale/trade 8 10-04-2015 05:30 PM
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 PM
Is my swirl pot design okay? FrankB Race Prep 10 10-02-2015 10:00 PM

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -4. The time now is 12:57 PM.