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LTX and LSXPutting LT1s, LS1s, and their variants into Third Gens is becoming more popular. This board is for those who are doing and have done the swaps so they can discuss all of their technical aspects including repairs, swap info, and performance upgrades.
This is a different kind of post. I would definitely recommend that anyone wanting to do a 4th gen tank for an LSx swap, and are on the fence, to just do it. Additionally, don't bother with the corvette filter and all those fittings etc. If you get the tank with the plastic and metal lines, and the "T" block, you can use all those, the 4th gen filter and it will screw directly onto the 3rd gen hard fuel line (if you have a fuel injected car, TPI at least). I am running it just like a 4th gen, "returnless". the only thing I had to do was modify the 3rd gen bracket to hold the 4th gen filter parallel to the car instead of perpendicular.
Two weekends ago I ran my car at NJMP for the Ultimate Street car series. My car is a 92 Firebird, with a 4.8 and T56. The 4.8 is basically stock, except for the car intake, injectors and I made the exhaust just like a stock TPI car, crossing under the oil pan over to the right side of the car, using stock 4th gen exhaust manifolds. I trailered my car there, and I had driven to work a few times that week, so the tank was about 70 miles down from full. On Saturday I drove the autocross 9-10 times, and then did the road rally which was around 140 miles. Sunday I did the Speed/Stop a LOT, maybe 20 times, and I did 3 sessions out on the road course. I did all of that without buying any fuel, and I was running the last session on the road course with the tank under the 1/4 mark, and I didn't have one hiccup or stumble. I couldn't believe how well the factory fuel system worked. One of the other thirdgens was low on fuel during the day, I think just over or around 1/4 tank, and he was having fueling issues so he had to put some in.
After the race I parked the car in the driveway and the battery died while I was away to Idaho. Yesterday I let the car idle for about 20 minutes, then in the evening I drove across town, to get some take out and sat in the drive through to let the battery charge some more, and was gone ~45 minutes in total. This morning I put gas in the car, I had to, it actually stalled when I made a moderate brake to a stop sign. I put 16 gallons in. In total I got 234 miles on the tank for an average of 14 mpg, lol. When I usually get 320-360, which is around 20-21 for mostly around town, no highway miles but a lot of driving 25-45 mph to work and few stops in traffic.
This is just a testament on how well thought out, the newer fuel bucket systems really perform. If you are thinking about getting one, I would definitely recommend. Don't have to worry about rust, flexible fuel neck makes tank removal down the road easier and a fuel pump that is always submerged in fuel. The weight of the tank over steel is probably about the same though.
I definitely will be doing this, Scooter. I signed onto the thirdgen board this morning actually looking for someone who could tell me how this swap worked out. Are you using a stock GM fuel pump in there?
I have an early Racetronix pump that I bought years ago for my other swap, but that car had a fire. I pulled it out last year and it works well still, but I have heard there may be quality issues with the new ones.
If I were to buy another pump, I would look at the Aeromotive one, as long as it can be made to work with the venturi setup, otherwise I would do another Racetronix.
[QUOTE=scooter;6169892]One of the other thirdgens was low on fuel during the day, I think just over or around 1/4 tank, and he was having fueling issues so he had to put some in.
That was me!! Yes indeed , once I put some fuel in, the issue was resolved.
This year I think I should drop the tank and put in a big pump (for when I do throw a big motor in the car next year)....wondering if I should swap to a gen tank like you suggest . perhaps !
That was me!! Yes indeed , once I put some fuel in, the issue was resolved.
This year I think I should drop the tank and put in a big pump (for when I do throw a big motor in the car next year)....wondering if I should swap to a gen tank like you suggest . perhaps !
Doing the tank was very easy, I would go for it. Putting in a big pump won't help any if you're uncovering the pickup, or you could go to the pickups that sit on the bottom of the tank and can get almost every drop of fuel out of the tank http://www.autoperformanceengineerin...l/pickups.html
I have them in the tank of my 73 Camaro, they work great too.
I have a thread around here about this somewhere. I love the 4th gen tank, if you have a removable rear section on the exhaust, you can get the tank out in about 15 minutes. I used the 4th gen plastic lines, and a 4th gen filter, which screwed right on to the stock 3rd gen hard lines. I have a return system though, like the 97 vettes, so I cut the end off the return line and put a "fuel line repair kit" for the 4th gen lines on it. 5/16" I believe, then the 4th gen return line snapped right on to it.I even figured out the resistance values for the stock sender in the 4th gen tank, and replaced the resistors in the 3rd gen fuel gauge to read correctly.
Definitely a must have for just about every 3rd gen. I haven't come across a 3rd gen that didn't have a leaky, rusty metal tank.
I have a thread around here about this somewhere. I love the 4th gen tank, if you have a removable rear section on the exhaust, you can get the tank out in about 15 minutes. I used the 4th gen plastic lines, and a 4th gen filter, which screwed right on to the stock 3rd gen hard lines. I have a return system though, like the 97 vettes, so I cut the end off the return line and put a "fuel line repair kit" for the 4th gen lines on it. 5/16" I believe, then the 4th gen return line snapped right on to it.I even figured out the resistance values for the stock sender in the 4th gen tank, and replaced the resistors in the 3rd gen fuel gauge to read correctly.
Definitely a must have for just about every 3rd gen. I haven't come across a 3rd gen that didn't have a leaky, rusty metal tank.
lol! Well, I doubt that I have a leaky, rusty tank in my 1984. However I do seem to have developed some sort of crack in-between the pump and the pickup, and this might by why I am now shopping for a new engine... I'll know for sure later this year when I remove the tank for the post-mortem analysis.
...and please do tell us! What *are* the resistor values necessary for adapting the fuel sender to the third-gen fuel gage?
I installed a LS1 plastic tank for my LQ4 turbo build. Fit great. I had to cut 2" off the rubber fuel hose between the tank and 4th gen filler neck. I made a spacer mount to install the 4th gen filler neck in my '84 TA. Turned out pretty good.
I got a Squash Performance double pumper kit for the tank. It's was pricey but is a really nice piece. You can also have them install the correct fuel sensor to keep your stock gauge. I'm going to use -8an supply / -6an return with PTFE hose and Aeromotive adjustable fuel pressure regulator.
For me, the important thing is to have good baffling around the pump pickup to reduce problems during cornering. I also want to convert to the returnless system for the upcoming LS swap.
Clip/cut the sending unit wire at the old sending unit. Unclip the other end at the clip going into the interior of the car (do not cut this end).
Send the wire and the new sending unit to LonnieP at Lonnies Performance. He will do the resistor value conversion for you as plug and play.
I don't know the values myself if your DIY.
You also can change the resistors at the back of the stock fuel gage. The stock resistors in fuel gage are 82 Ohm and 22 Ohm. Here is a short writeup how I did it with my '89 Firebird. Edit: Doesn't work. Never has worked for anybody. It's an internet myth that needs to end.
Also, some aftermarket gages, such as Speedhut, allow you to select the type of sending unit so no need to change anything in that case.
I think the stock 3rd gen sending unit is 0 - 90 Ohm range. You would want to swap out for a sending unit with that range.
You also can change the resistors at the back of the stock fuel gage. The stock resistors in fuel gage are 82 Ohm and 22 Ohm. Here is a short writeup how I did it with my '89 Firebird.
I installed a LS1 plastic tank for my LQ4 turbo build. Fit great. I had to cut 2" off the rubber fuel hose between the tank and 4th gen filler neck. I made a spacer mount to install the 4th gen filler neck in my '84 TA. Turned out pretty good.
I got a Squash Performance double pumper kit for the tank. It's was pricey but is a really nice piece. You can also have them install the correct fuel sensor to keep your stock gauge. I'm going to use -8an supply / -6an return with PTFE hose and Aeromotive adjustable fuel pressure regulator.
The rubber hose & fuel neck are both 4th gen pieces. I made a spacer to mount the filler neck using the existing bracket that is on the neck. Then I cut the rubber hose down to fit between the neck and tank. Here’s some pictures:
Do you have a Camaro? I didn't need to use a spacer for my Firebird
Do you have any pictures of what you did?
I have a Trans Am. If i didn't use the spacer the filler neck would rest on the bottom of the fuel door bucket. It's still not perfectly centered in the fuel door opening but I didn't want it rubbing. I purchased a new neck from Rock Auto. Maybe the geometry isn't exactly right??
Do you have any pictures of what you did?
I have a Trans Am. If i didn't use the spacer the filler neck would rest on the bottom of the fuel door bucket. It's still not perfectly centered in the fuel door opening but I didn't want it rubbing. I purchased a new neck from Rock Auto. Maybe the geometry isn't exactly right??
I don't, I did the same as you, but I didn't use the spacer, there was even a hole there that I used so I didn't have to drill. I will try to remember to take a picture of the filler. I think i just have it resting in the internal part, does't bother me, but it could just be bent slightly, or maybe I did bend it slightly. I don't remember now
Clip/cut the sending unit wire at the old sending unit. Unclip the other end at the clip going into the interior of the car (do not cut this end).
Send the wire and the new sending unit to LonnieP at Lonnies Performance. He will do the resistor value conversion for you as plug and play.
I don't know the values myself if your DIY.
That's definitely worth the money. There are threads about using a Grand Prix fuel level sensor. That sensor is plug and play for the 2nd GM fuel bucket design. I found out the hard way that there are two OEM designs. They had different wire harness plugs at the top. The aftermarket fuel buckets for the 4th gen tank have different connection clips for the fuel level sensor. Sense the fuel bucket and sensor are submerged in gasoline, the wires can't be spliced, and the sensor must be securely mounted on the bucket. I finally figured out a solution after much trial and error.
I got a question. I too opted for the 4th gen plastic tank in my 89 rs. So the question is, is the 4th gen fuel tank purge valve wired same as the 3rd gen? I was thinking about splicing into the factory harness behind the left headlight, then running wire down the left side of the car to the tank where the 4th gen purge valve is. Any thoughts, concerns, corrections, or criticism?
I got a question. I too opted for the 4th gen plastic tank in my 89 rs. So the question is, is the 4th gen fuel tank purge valve wired same as the 3rd gen? I was thinking about splicing into the factory harness behind the left headlight, then running wire down the left side of the car to the tank where the 4th gen purge valve is. Any thoughts, concerns, corrections, or criticism?
4th gen purge is mounted on the driver side of the engine I believe. The solenoid operated valve on the tank is the vent valve.
The rubber hose & fuel neck are both 4th gen pieces. I made a spacer to mount the filler neck using the existing bracket that is on the neck. Then I cut the rubber hose down to fit between the neck and tank. Here’s some pictures:
An easier way is to bend the bracket by hand, line up the filler neck with your body, then drill a hole where the bolt will screw through the frame and into the bracket.
Then use the factory 4th gen bolt, it's what I did on my car and the filler is centered perfectly
Obviously this mod is very popular among lsx swappers. But what about the few that want a plastic tank on their stock engine like me? Has any one done this swap with a factory engine? I'm curious how you went about your emission setup.
I’m running a complete LS1 / T56 swap and a complete emissions / functioning evap system. 4th gen tank has all factory wires connected to the 411 ECM and gauges from Dakota Digital. Here’s the kicker - we all know you either send the fuel data to the ecm or the gauge, you can not splice to both. However, they make a OBDII connection which includes the fuel data!
Bingo!
Fuel gauge works perfectly and computer is getting the pressure/level/etc info it needs to purge and vent.
Who makes an OBDII fuel data? And why would an OBII make your fuel gauge work? Im not understanding sorry. Im looking to get my stock fuel gauge working with a 4th gen Ls1 fuel sender. I have a Dakota Digital box for my tach. Will it work for fuel sender too??
Who makes an OBDII fuel data? And why would an OBII make your fuel gauge work? Im not understanding sorry. Im looking to get my stock fuel gauge working with a 4th gen Ls1 fuel sender. I have a Dakota Digital box for my tach. Will it work for fuel sender too??
Nope. Can’t use stock gauges. Their gauges and the bus kit allow the Dakota Digital gauges to read direct from the ECM.
Hello, I know this is an older post however, I have completed most of my LS swap in my 83 Camaro used 4th gen tank all works great EXCEPT, I cant fill the tank because the vent assembly in the pump head simply will not allow air to be pushed out. It appears to all be there however has a tiny little hole at the top with a spring assembly valve built in. Can I simply drill that out and then just use the 3rd gen vent valve at the end of the vent line? This is literately my ONLY problem, but I am stopped cold.
09-19-2017, 08:31 AM
