need a little help on a tpi swap

[Andy4639]

You have a few ways to get the gas out of the tank. One is build a small sending unit tank to mount under the truck to the frame. Put a electric pump in line to fill it are gravity feed it. It will also house the pump for the motor and the return line.

The one I like the best is. Take the orignal tank out of the truck and measure the bottom front side of the tank and build a box to weld to it. Mark the tank where the outline of the box. Drill holes into the gas tank and weld a fitting for the fuel line into the new box then weld the box to the tank. Then use a inline high out put pump to the motor with filter on both sides of the pump.
Are buy a fuel tank for fuel injection and mount it in the frame.

[birdman8711]

ok guys engine and trans are in and moving along now im having an issue with my driveshaft i have a 72" single piece and need a 69" or 70" i was wondering if you know of any gm vehicles that have one or should i just get mine cut

[mmiddle]

Get it cut, they will balance it and all.

Post some serious pics when you are done. I have two 87 IROC's and was thinking about taking one of the TPI's out for my sons 75 stepper.

[Andy4639]

I'm fixing to have a complete combo 305 HO TPI/700R4 took out of my 71 to be replaced with a 6.0 LSx. If anybody is intersted PM me. Complete Street & performance wiring harness 4 wires and it's running.

[MalibuSSwagon]

Originally Posted by mmiddle

Get it cut, they will balance it and all.

Post some serious pics when you are done. I have two 87 IROC's and was thinking about taking one of the TPI's out for my sons 75 stepper.

check out my build thread in my sig, I have converted my 86 C10 to TPI.

[MARKDTN]

I did not see the photos well earlier. I would not use those brass unions, especially on the pressure side. Those gas unions are made for 4-5 psi and are being used at over 40 and even higher at times. You are much better off to use hydraulic unions that are rated for high pressure. You do not want leaking pressurized fuel.

[stevencvn72]

Originally Posted by LockDoc

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You can use your stock tank if you run a 1980 Datsun 280zx (Nissan) external Fuel pump, Available at Advance Auto Parts, p/n E8312.. $106.09. (online price)

http://shop.advanceautoparts.com/web...lVehicle=false

You don't have to run a return line to the tank, you just put a "T" in the line before the pump and it sucks it back into the fuel supply line.

LockDoc

The "t" is a great idea! I can't believe nobody ever gave me that idea when I was plumbing my TPI. Seems like that would alleviate cavitation problems too. Dang!

[birdman8711]

Originally Posted by LockDoc

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You can use your stock tank if you run a 1980 Datsun 280zx (Nissan) external Fuel pump, Available at Advance Auto Parts, p/n E8312.. $106.09. (online price)

http://shop.advanceautoparts.com/web...lVehicle=false

You don't have to run a return line to the tank, you just put a "T" in the line before the pump and it sucks it back into the fuel supply line.

LockDoc

when you say before the fuel pump do you mean between the tank and pump

[LockDoc]

Originally Posted by birdman8711

when you say before the fuel pump do you mean between the tank and pump

Yes, on the intake side

LockDoc

[MARKDTN]

Originally Posted by stevencvn72

The "t" is a great idea! I can't believe nobody ever gave me that idea when I was plumbing my TPI. Seems like that would alleviate cavitation problems too. Dang!

Has anyone used a "T" with sucess on a TPI? I tried that once on a carb motor swap in an old Jeep with an electric fuel pump and had too much air in the system. I had to add a return to the tank to make it work. Some of the late LS stuff has a filter that is a return, so I guess if you had a check valve in the right place it could work. Just curious if anybody has one running on a TPI swap?

[LockDoc]

Originally Posted by MARKDTN

Has anyone used a "T" with sucess on a TPI? I tried that once on a carb motor swap in an old Jeep with an electric fuel pump and had too much air in the system. I had to add a return to the tank to make it work. Some of the late LS stuff has a filter that is a return, so I guess if you had a check valve in the right place it could work. Just curious if anybody has one running on a TPI swap?

I don't have mine running yet. There would be a lot of difference between a 7psi carbed setup and a 45 psi injected setup. I can't see it getting any air in the injected system. I also don't know why you would need a check valve since there would be no back pressure on the return line.

LockDoc

[MARKDTN]

Originally Posted by LockDoc

I don't have mine running yet. There would be a lot of difference between a 7psi carbed setup and a 45 psi injected setup. I can't see it getting any air in the injected system. I also don't know why you would need a check valve since there would be no back pressure on the return line.

LockDoc

If you can ever get all the air out, it might work. Whatever air is in the line has to be bled out. I suppose if you didn't "T" it to begin with and ran the pump until all the air was gone, then T'd it, it might work. Otherwise, you will never get all the air out. I think you will just create a giant air pocket at the suction port of the pump and it will cavitate and not pump any fuel and the process will stall. I do agree that a check valve will not help.

I do not see any big advantage to this method anyway. Why not just return to tank? That keeps the hot returned fuel circulating and will result in cooler denser fuel that should result in more power and longer pump life.

I hope it works. I am still curious if anybody has one running with this setup.

[jaros44sr]

My TPI has a shrader valve on the passenger side fuel rail, couldnt you bleed off any air with that valve. Seems like it would be the high spot in the system

[68 TT]

Originally Posted by birdman8711

ok guys engine and trans are in and moving along now im having an issue with my driveshaft i have a 72" single piece and need a 69" or 70" i was wondering if you know of any gm vehicles that have one or should i just get mine cut

If you put the engine in the forward mount holes it can use the 72" driveshaft but I would have the driveshaft shortened and keep the engine set back in the rear mount holes for a little better weight distribution and more room up front for the accessory drive.

[MARKDTN]

Originally Posted by jaros44sr

My TPI has a shrader valve on the passenger side fuel rail, couldnt you bleed off any air with that valve. Seems like it would be the high spot in the system

The way the system works with an external pump is this:
1-fuel either by gravity or with another low pressure pump is fed to the suction side of a high pressure pump. This pump is below tank level so it should have no air trapped at the inlet.
2-pressurized fuel is pumped to the rail and to the injectors where some of it is returned at the fuel pressure regulator between the 2 banks. This is how pressure is maintained, by returning extra fuel. The schrader valve on the rail is a way to see how much fuel pressure the injectors are seeing. You can't bleed the line past the regulator with this port.
3-returned fuel is generally dumped back to tank where it mixes with all the remaining fuel in the tank. The act of pumping heats the fuel some due to friction and pressure. So returning fuel to the tank allows the tank itself and remaining fuel to act as a cooler.
4-the cycle repeats.

If you "T" into the suction side before the pump, you will have a hard time bleeding the system because you are pumping a fuel and air mixture under some pressure until the return line is completely full of fuel with no air. This mixture is under more pressure than the gravity feed from tank so therefore no fresh fuel will be able to take the place of the trapped air. That is what I think will happen. This is what did happen on the Jeep I described. I could be wrong. As I said, I know that some late LS Corvette setups do not use a return line and do return through the fuel filter BUT the LS setup is returning after the pump so it is never trying to pump air. I have never heard of anyone trying this with a TPI and I still think that the fuel has to be hotter because of it.

Anybody out there with a running TPI that is using a "T" in the fuel system?

[jaros44sr]

Sorry didnt read enough of the thread... I have a 2000 camero intank pump, but my tank is under bed, so no help here.

Guess well just have to wait till Lockdoc gets his running to see if it works

[Zeke's Garage]

For my TBI MegaSquirt build, I put an in-tank pump I had from my old '94 Z-71 pickup, and grafted it onto the original sender pickup. I should have noted how much of the original pickup tube I trimmed, but it's pretty self explanatory. I also put in a return nipple to the top of the sender for the return line. Check out the attached pics to see how it worked. You'll notice the copper return line that's brazed to the brass nipple that serves as the fuel return. It's not pretty, but it doesn't leak and I've got good consistent pressure.

I did have to notch the top of the fuel tank where the sender goes in to allow the pump to slip inside. You have to rotate the assembly a couple of times while putting it in, but if I was able to sort it out, I'm sure anyone can.

I heard all sorts of warnings and blatherings about how using an in-tank pump wouldn't work in an unbaffled, unsumped tank. How it will suck air and cause no end of drivability issues. Well, I've got about 3k miles on this setup with the MegaSquirt ECU, and other than a cracked head on my inline 250 (not the fault of the pump I assure you), The drivability has been great, and I've never noticed any issues at a nearly empty tank. So if you're on a budget, I would not hesitate to try this option.

Good luck!

Shawn

[MARKDTN]

Originally Posted by Zeke's Garage

...I heard all sorts of warnings and blatherings about how using an in-tank pump wouldn't work in an unbaffled, unsumped tank. How it will suck air and cause no end of drivability issues....

I agree. A baffle helps but is definitely not required. Contrary to popular beliefs, '82 Corvette tanks are not baffled (the first electronic fuel injected small block). I have done at least 2 fuel injection swaps using unbaffled tanks with no issues at all. They just keep at least 1/4 tank and neither has any issues with at least 20K miles between them.

[Undone]

Subscribed

[Orange Crate]

I am also swapping in a TPI and have read as much as possible hear and other places. One write-up I saw was concerning the return line back to the tank. The guy didn't put the return line all the way down to the bottom of the tank, sort of had it dumping in at the top. The issue was the fuel got aerated and he had some hesitation issues because of air in the fuel going into the pump until he figured out what was going on. Anyway I thought it was a good tip. Here is a good site for general TPI info:

http://www.chevythunder.com/

[LockDoc]

Originally Posted by jaros44sr

Sorry didnt read enough of the thread... I have a 2000 camero intank pump, but my tank is under bed, so no help here.

Guess well just have to wait till Lockdoc gets his running to see if it works

That may be a while. I have to finish the '70 Chevy 4x4, the '34 Ford, and the '36 Ford before I start on the '70 swb again. I am close on the 4x4 and the '34 but I have quite a bit left to do on the '36.

LockDoc

[Longhorn 70]

I have always liked the looks of the L98 TPI mills. I had one in a 90 Corvette. It had so much grunt down low. It always seemed to me that it would have been a better truck engine than sports car engine.

Great gas mileage, reliability, reasonable performance, and sweet looks are just a few of its assets. I have thought about putting one in my pickup but never did. Please post pics of yours as you go along. I'm betting it will be a great ride.

[jaros44sr]

Originally Posted by LockDoc

That may be a while. I have to finish the '70 Chevy 4x4, the '34 Ford, and the '36 Ford before I start on the '70 swb again. I am close on the 4x4 and the '34 but I have quite a bit left to do on the '36.

LockDoc

No problem Leon, im patient....

Heres mine in its present state


20131010_113914 by jarosaj, on Flickr


20130804_083211 by jarosaj, on Flickr

[birdman8711]

this is my fuel pump and filter combo im using my stock tank will upload a pic of my sending unit once its done. its a walbro inline pump 60psi max($112 from summit) and a stock replacement filter for my camaro which is a 10 micron($15 from autozone)

[Z10]

Interesting thread. I've ordered a F.I.R.S.T TPI system and hopefully will it will be delivered in the next couple of weeks. It's going to sit on top of my ZZ4. This set up is pretty much a factory TPI system on steroids.