Red97Z

iTrader: (22)

Is it possible to delete the EVAP system on an LT1? What is it's purpose? I'm not concerned about emissions either.

Fire67

iTrader: (3)

Its very possible (and easy)... Its there for a way of venting the gas tank without upsetting your nose with fumes. Basically it uses engine vacuum to pull the fumes out of the gas tank and into the motor to be burned.

Just remove everything, install a filter or vent fitting on the plastic EVAP line, and delete the SES codes with LT1edit or TunerCats.

I put a check valve in the end of my plastic line and tucked it away inside the drivers side fender.

Red97Z

iTrader: (22)

Do you have any pics? I'm going to remove everything on the passenger side of the manifold, but am unsure of what to do with the line that comes off of the fuel lines and hooks down under the throttle body.

Fire67

iTrader: (3)

That line (grouped with 2 fuel lines) is the vac. line that goes to the tank. I pulled it out of the engine bay and into the fender well. Cut about 1 1/2 ft off of it and rigged a check valve on there. Basically I got a summit '6an check valve, a -6an to 1/4" NPT adapter, and a 1/4" NPT to a barb (hose) fitting. I put the barb into the plastic line (heat line first for easier insertion), threaded my adapter fitting to that, and then attached the check valve to my adapter.
The whole deal is looped over to point the check valve in the correct direction and zip tied to stay in place.

Plug the fitting below the TB, remove the funky shaped plastic line that goes to it, then pull the vent line out of the loom and into the fenderwell.

Sorry no pics yet, my normal pc crashed friday and I have not been able to load any new pics as the software is on that pc.

slckstr96

iTrader: (4)

i have been wanting to do this ever since i got my z. what about the other thing that is right by the evap solenoid (think it is vacuum canister or something like that, not sure) can that be taken off too?

InsaneAuto86

iTrader: (60)

I would like to do this as well. Could someone make a !parts list or some pictures? thanks

hyperzone

Instead of even keeping the whole metal line from the canister to the front, could you just disconnect/remove/cutout that and tie in the check valve to where it attaches to the canister? Do we even need the canister if we dont car about emissions or some fumes? Does there have to be a vent of some kind or can it just be all removed and capped/blocked off???

Red97Z

iTrader: (22)

Someone must have done this, please chime in!

transam5.7lt1

iTrader: (18)

I would like some info on that too!!!

Fire67

iTrader: (3)

You need a vent of some sort for sure. I only left my line going forward from the tank/canister out of lazyness. Instead of pulling the whole system I just put a vent on the line. I do not smell any fumes from it.

You could pull everything tied into the EVAP system and just put a vent in the back where the line would originally go into the charcoal canister.

Its fairly simple guys, just remove everything thats plumbed into the evap system(electrical or not), cap off the vacuum ports on the manifold, add a vent where you wish.
If you decide to remove the cannister from the back and put a vent there, understand that you will smell fumes. If you leave the cannister, there will not be any fumes.

Fire67

iTrader: (3)

Im about to start posting pictures of my build, which happens to be coming to an end and should be racing within 2 weeks. My normal pc crashed and I dont have my cam software on this pc... As soon as my normal pc's fixed, I'll start posting pics. If any of you still need help then, pm me and I'll get you whatever pics I can.

Ls1Bait

^^^^^cant wait to see some pics

the_merv

iTrader: (88)

Yea, I am interested as well. I want to get rid of all the EVAP crap on the Engine. I already deleted it out of the Harness, so I don't want it on the Engine. I am just goin to run the line to the Intake somewhere.

Red97Z

iTrader: (22)

merv- what did you remove from your harness? All of the connections to the purge valve or what? bump for pics!

Fire67

iTrader: (3)

If you do that without all the electronics, you will have continous vapor flow. This will not be good as it will mess with the A/F ratio and needed timing. The pcm seems to adjust both when the EVAP purge is commanded.

Just cap the line with a vent or something. I only used a checkvalve to keep the NHRA tech guys happy. Its only gonna help if I somehow roll the car onto its roof.

Just put a checkvalve somewhere on the line from the tank, delete all the components you dont want anymore, and cut the harness connectors off (which you have already done)... Not hard. The system is only there to use engine vacuum as a way to remove the smelly vapors from the tank before they can escape. So if you delete the EVAP system, this becomes your tanks external vent.

the_merv

iTrader: (88)

I got rid of it out of the LSX Harness that I am messing with for the Car. It had a few more things than the LT1 in that Harness. Go to sxbox.com, he has all the pin diagrams for the wires that go to the connectors on the PCM.
It has 4 lines that come off of it on the Sending Unit, I believe one of those is a vent already. I could see dropping it under the Car somewhere as a vent, since those Vapors rise, and it will keep them contained more.

Fire67

iTrader: (3)

1)Feed to rails
2)Return to tank
3)EVAP line
4)??? You got me, Im almost 100% positive my 96 only had three lines coming out of the sender.

The tank vents while filling via a tube inside the filler neck thats spot welded to the top of the neck above where gas would exit the filler nozle...

Im gonna see if I can dig up any pics of my tank to show you. I had it out to be sumped and took lots of pics. Now to find them

the_merv

iTrader: (88)

I got a pic at home of when I cut to get to the Fuel Pump..This one is similar.

Fire67

iTrader: (3)

Damn, now I remember seeing it, but dont remember what that 4th one goes too. Let me see If I can dig up an EVAP diagram somewhere... Pretty sure I have one laying around

1SlowFormula

seems like good info, subscribing...