im putting an lt1 in my 92 rs 305 tbi. my question is, instead of dropping the gas tank to put a tpi fuel pump(45psi) could i leave the tbi one in there and just add another pump on the fuel line? or would a regulator at the fuel rails be something too? thanks for any help guys.

 

tpi, and fuel injected v6 thirdgens all have the same fuel pump. The regulator for the LT1 is on the LT1 fuel rails.

**edited because of bad information**

 

You might research that one again Firebat. TBI IS NOT the same pump as TPI or V6. TPI and V6 are high pressure pumps. TBI is a low pressure pump.

 

My bad, you are correct.
http://www.geocities.com/texaslt1/lt1swap/fuel.htm


Just drop the tank and install a high pressure pump. Its really not bad.

 

If you'e doing all the work of a motor swap, dropping the gas tank is no big deal. Since you're going LT1, I would suggest the Walbro 255 lph pump. It's about the same price as the stock TPI(maybe cheaper), and will support any mods you decide to do in the future. The problem with adding an external pump is that it has to suck past the stock pump to get fuel. Even with the stock pump running, theres a chance you'll out flow it and strain the external pump or starve the system for fuel.

 

thanks for the help, i was just hoping with all the labor involved in swapping the engine i wouldnt hafta have the extra ordeal of dropping the gas tank. i geuss in the long run it would be better anyways right? ive heard you have to drop the whole rear end and everything... is this true?

 

While the factory used different pumps for those application, the aftermarket will sell you the same one for any of them. That's because the regulator will take care of the pressure, and the pump simply supplies volume. Also, a TPI pump will work in a TBI application, although a factory TBI pump won't work in a TPI application. So, what the aftermarket is selling you is a TPI pump, that will work with TBI or V6 SPFI.

For what that's worth.

In this specific case, I agree - drop the tank and put in a proper pump. You could put in an in-line pump and let the TBI pump be a pusher to it, but the TBI pump is going to be the weak link in the system. Not worth the hassle, and the TBI pump is eventually going to fail.

 

I was afraid of the dreaded "tank drop" task, but it turned out to be not so hard. Even with my semi-rusty WI car it was only an afternoons work to get the tank out and back in. You don't have to drop the whole rear end, just unbold it enough so that it will swing down on teh control arms and torque arm. The biggest thing to remember is to get the back of the car as high as possible. The higher the better because you have to manuver the tank some to get teh filler neck out.

Oh, and be sure it's very near empty too. Gas weighs more than you'd think it would...

 

Just do it right.