UofA_ZCar Posted June 24, 2012 Share Posted June 24, 2012 I have read through the posts I could find, but didn't find the answer. Referring to the diagram below it seems like the stock LS1 gas tank vented to the throttle body. Can I just vent the stock 240z tank to the LS1 throttle body using the stock 240z vent line that runs to the engine bay? The only difference I see is that I would not have a evaporative canister or a control valve but the stock 240z didn't have one anyway. Could really use some advice from someone smarter than me on this one. FYi I am running the stock gas tank with a sump and stock expansion tank (small tank in passenger rear of car). Thanks Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted June 25, 2012 Share Posted June 25, 2012 Send a pm to AeroZ. He just worked on this on his car. I think you just vent to atmosphere. Quote Link to comment Share on other sites More sharing options...
Aero Z Posted June 25, 2012 Share Posted June 25, 2012 I am running the LS1 tank (not the Z tank) so my setup is a bit different. From my understanding the stock LS1 engine/setup (and on that schematic) runs the LS1 tank vent (out of the LS1 sender) into the charcoal canister. Once the tank vapors are cleaned some by that there's another line that runs to the throttle body to burn any vapors that still may be there but its not necessary. If you are running a stock Z tank your vapors are already going into the expansion tank. So don't think you need to do anything. Just plug up the inlet tube on the throttle body (remove the valve assembly going into it). Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted June 25, 2012 Share Posted June 25, 2012 (edited) Oops. My bad. I thought you were running the LS1 tank. I need to learn to read. I have a stock 240 z tank. I chucked the charcoal canister and ran a single vent line up into the inner fender as high as possible then looped it back down under the car to open lower than the tank ( to limit fumes ) and I put a little filter on the end to keep spiders out. I eliminated all but one vent. I thought it would be ok but I have to fill really slow to get a full tank. I built an internal sump into the tank trying to copy a 280z internal sump/baffle. It doesn't work perfectly and I do fuel starve on turns below 1/4 tank. My next tank will have a larger vent hose ( like 3/4 inch instead of 3/8) and an external sump hanging a few inches below the tank with an internal pickup,access hole and drain plug. If you plan to leave your tank stock, I bet you can run a line from the charcoal canister to the EVAP port on the throttle body. So long as the port is before the butterfly the little vacuum leak shouldn't affect tune. be sure to put a cleanable filterl before the tank. All tanks are dirty, even new ones (manufacturing debris). Edited June 25, 2012 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
UofA_ZCar Posted June 25, 2012 Author Share Posted June 25, 2012 If I understand the replys than I could just vent the tank to a charcole canister and I shouldn't have issues with gas fumes..... no need to tie it into the engine. Correct? I have a stock 240 z tank. I chucked the charcoal canister and ran a single vent line up into the inner fender as high as possible then looped it back down under the car to open lower than the tank ( to limit fumes ) and I put a little filter on the end to keep spiders out. Do you get any of the typical gas smell inside the Z with this set-up? I am trying to make sure I don't have the gas smell that is common inside the early Zs. Thanks for the help! Quote Link to comment Share on other sites More sharing options...
svMike Posted June 25, 2012 Share Posted June 25, 2012 If I understand the replys than I could just vent the tank to a charcole canister and I shouldn't have issues with gas fumes..... no need to tie it into the engine. Correct? Do you get any of the typical gas smell inside the Z with this set-up? I am trying to make sure I don't have the gas smell that is common inside the early Zs. Thanks for the help! Venting to a charcoal canister will help with most of the gas fumes, but the canister itself will need to purge somewhere, that's why it is connected to the intake via the purge solenoid. If you look at how the current GM E-rods are set up, the canister has 3 ports - from tank vent, to purge solenoid, to atmosphere. If you remove charcoal to purge, you may have slight fumes depending on how long the car sits and how hot the day gets. You will also need to get EVAP circuit removed from your ECM. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted June 25, 2012 Share Posted June 25, 2012 On a 240z there is a little triangular tank in the passenger rear fender. It is a vent tank. It has no charcoal in it. I don't know about other models. It needs to vent somewhere. That is what the vent line in the engine compartment connects to. It used to vent the fuel tank vapors into the carburetor air cleaner where they got sucked in and burned up. You can just hook that into the throttle body so long as the port used is before the butterfly. If all your vent lines se in good shape, the fuel stink associated with the z car is from an over rich mixture and the subsequent unburned fuel stinking up the exhaust which then gets sucked in the hatch by the low pressure zone behind the car. If your new setup has computer controlled fuel injection your car will be less smelly due to better fuel metering. Quote Link to comment Share on other sites More sharing options...
UofA_ZCar Posted June 25, 2012 Author Share Posted June 25, 2012 On a 240z there is a little triangular tank in the passenger rear fender. It is a vent tank. It has no charcoal in it. I don't know about other models. It needs to vent somewhere. That is what the vent line in the engine compartment connects to. It used to vent the fuel tank vapors into the carburetor air cleaner where they got sucked in and burned up. You can just hook that into the throttle body so long as the port used is before the butterfly. That is really my main question. So I can hook the vent line in the engine comparmtent directly to the throtle body in the same spot that the EVAP control valved used to hook to? ....... and I can do this without any negative effect on gas tank pessures? Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted June 25, 2012 Share Posted June 25, 2012 (edited) So long as you have a vented cap, yes. You will have air sucking into tank thru vented gas cap pulling vapors off the tank to be consumed by the engine. That keeps your tank at about atmospheric pressure. Edited June 25, 2012 by RebekahsZ 1 Quote Link to comment Share on other sites More sharing options...
UofA_ZCar Posted June 28, 2012 Author Share Posted June 28, 2012 So long as you have a vented cap, yes. You will have air sucking into tank thru vented gas cap pulling vapors off the tank to be consumed by the engine. That keeps your tank at about atmospheric pressure. I recall reading somewhere on HybridZ that the stock gas cap does not seal air tight, so in theory I should be good to go correct? Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted June 29, 2012 Share Posted June 29, 2012 I see conflicting info on the venting or non-venting status of the caps. Perhaps someone else am weigh-in? Quote Link to comment Share on other sites More sharing options...
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