TBI to TPI swap

[ryan34]

Alright, i think i'm gonna swap the intake setup, off my car and put in a TPI setup. I've seen some "complete" systems on ebay and want to eventually get one. Now with the TPI, is there different sensors i need to worry about? If so, which ones would i need. Also, i've found that as the years got newer in the 3rd gen. They got more power with the same engine, does anyone know if it is because of the intake or the engine. Or both? If its the intake, then i would like to buy one from a newer year car. And last but not least, can i swap the ones from the 5.7 and corvette onto my engine? Thanks for any advice.

[Joe 1320]

TPI setups along with the camshaft, is tuned for huge low end torque. The intakes will interchange, but were originally designed for the 305. The TPI setup found it's way on a 350 but when the mods start being added, the TPI quickly runs out of breathing at higher RPMs. This is why it is ideally suited for a 305 torque monster. If you plan on changing over to TPI you will need to upgrade the fuel system. TPI takes much more pressure and volume than a TBI. IMHO the easiest way would be to find a donor car and pirate the whole engine with accessories along with the front wiring harness. This way you can transfer all the componants over to your existing long block and have another long block to spare.

[Benm109]

I'm no expert on TBI to TPI swaps, but you are going to at least need an engine wiring harness from a TPI car, the whole intake manifold (runners, plenum, etc.), air filter set-up, upgraded fuel system (fuel pump, fuel filter, etc.), and probably all new sensors (MAP, or MAF sensor depending on what year TPI wiring harness you get, CTS, EGR, EGR vac. solenoid, IAT, etc.), and some other odds and ends. You can put a Corvette TPI set-up on your car, they had the exact same engines as the Camaro/Firebird at the time. I'm sure that there's probably some tech articles or stickies for this swap at www.thirdgen.org . I agree with Joe 1320, you're probably better off with a donor car, but like I said, I'm no expert.

They list different HP and TQ ratings on the same engine because of all kinds of reasons. Sometimes the manufacturer will detune the camshaft after a couple of years, switch between a speed density or a MAF set-up, upgrade certain aspects of the transmissions, etc.

[ryan34]

Well because of funds and lack of space, just a TPI swap would be ideal. I just wanted to make sure that when i got one, that I bought it whole. That way when it was all and done, that i would really be done and not have to go out and buy on last part. Now for the fuel system, which fuelpump should i go with? I am not really looking for real high performance. Just basic bolt on stuff, and the TPI of course, but no internal engine mods. Would the Stock TPI fuel pump work fine? Oh, and will i NEED the cam from the TPI, or could i use my stock one?

[Benm109]

A stock TPI fuel pump will be fine. It'll bolt right in. I don't see why you couldn't use your stock camshaft. But, like I said earlier, I'm no expert on this kind of swap, but I do know 3rd gens.

[Benm109]

Here's a link to a tech article I found:

http://www.thirdgen.org/newdesign/tech/tbitotpi.shtml

[ryan34]

Thanks for the information

[WICKED LT1]

Be aware that the year of the donor car dictates a few things. The earlier (85-87) units were mass air, and used a 9th injector for cold start on the driver side of the intake. The 88-89 (I think) was mass air and no 9th injector. It used extra pulsewidth on the other injectors for cold start. and the 90-92 units were speed density and no 9th injector. Also these all had different part numbers for the ECM and memcal.

Make sure that you get the rights pieces for the right year. You may also want to be a little picky about which year you get. Some are better than others. The newer systems had faster cpu's in the ecm so they tuned better. Also, some people like to get the mid year mass-air based units because the mass air is more receptive to modification to airflow than the speed density ones. Good luck with it.


-Paul

[ryan34]

Be aware that the year of the donor car dictates a few things. The earlier (85-87) units were mass air, and used a 9th injector for cold start on the driver side of the intake. The 88-89 (I think) was mass air and no 9th injector. It used extra pulsewidth on the other injectors for cold start. and the 90-92 units were speed density and no 9th injector. Also these all had different part numbers for the ECM and memcal.

Make sure that you get the rights pieces for the right year. You may also want to be a little picky about which year you get. Some are better than others. The newer systems had faster cpu's in the ecm so they tuned better. Also, some people like to get the mid year mass-air based units because the mass air is more receptive to modification to airflow than the speed density ones. Good luck with it.


-Paul

Is there any benefits to the speed density? Plus does anyone know what it would cost to get all the equipment new from a dealer? I'm pretty sure it would cost a pretty penny, but i want to weigh my options. Plus there's the added insurance of buying the stuff new.

[DeWynter]

Speed density allows you to put a Air filter directly on to the intake plenum. Speed dencity does not take modes as well as the Mass air flow because MAF mesures in coming air better. I have an almost complete SD TPI setup I want to sell includes Computer, intake, plenum, injectors(305), Runners and throttle body. $650 + Shipping, comes with a 350 and 305 eprom. The wire harness can be bought for an extra $150 new at year one or get one from a junk yard for $20