I have found a 79 w/4 speed here locally, really cheap. I am thinking about turning it into my project car as I dont want to alter the PC too much. I have a spare TPI setup (without the harness) off an 88 IROC that has been collecting dust on the shelf of my shop for a couple of years. I'm sure someone has done this, so how hard would it be to install the TPI system? What all would I have to buy sensor wise?
And will it fit under the hood?

Any pics?

 

Since you don't have the harness anyway, I would get a computer and harness for a later model (89-92 I think), which are speed density. That way, you won't need the MAF or have to worry about where to plumb it. You'll need oxygen sensors, the MAP and TPS...the rest depends on emissions laws in your area.

 

Do you know if it will fit under the hood?

 

It will Here is a pic of mine (before hose routing change!)



Here is a link to a recent thread on the subject:

http://forums.corvetteforum.com/show....php?t=1950534

It is a neat project. I would advise switching to Speed density if possible.

 

Good point on the speed density. I still have an 88 IROC I bought new behind the shop and had planned on just ordering duplicate parts for it, but I dont want to fool with the MAF and all the PITA stuff on it.

 

Here's a pic of a 1990 TPI setup on a ZZ4 in my 1980. Fits under the stock hood.

 

Looks good, I have a 73 that I'd like to modify with the TPI system. I was told that the bolt patterns of the TPI system changed at some point in time and I needed to make sure I get the one which will bolt to the eariler heads.

What years TPI systems bolt to the earlier heads?

Thanks

 

i had a 87 setup on my world products heads so at least 87 and under.
http://rides.webshots.com/photo/1175...52841409DFmkyh

 

as stated above just get any 85 or 86 TPI Set-up from a 305 / 350 Camaro or Firebird and it will bolt to the pre-86 heads with no issues

I would also switch to speed density and buy these two books before you start your project.....it'll get you going in the right direction

amazon.com has them pretty cheap or you can go to mike knell's website for the first one.....www.jagsthatrun.com

 

Awesome!!

I see you did an upgrade...What did you do with the TPI unit after the upgrade?

 

MIne?i took the whole motor and installed into a 80 vette for a friend(bcpockets) here on the forum.As for the 87 setup you need to drill the center bolt holes on angles for them to bolt up also.

 

You have a unit
First you have to determine whether you want mass air flow or speed density. The C3 is more conducive to speed-density due to space issues. Mass-air flow is easier to make engine changes without PROM changes. If you are technically proficient enough to make a Camaro harness work they can be bought for $100 or less. I have been told that you can also use a 3.1 Corsica or Cavailier harness with a little work, it uses the same 7730 Speed-Density ECM. Aftermarket harnesses range from about $300 for Painless to $500 for Howell to $700 for Street and Performance. Howell makes a great harness, but for a Tuned Port they do not make one that will control the converter lockup on a 200R4/700R4/4L60 transmission. If you are running a manual or non-overdrive-automatic transmission I highly recommend them. I have heard great things about Street and Performance harness, but do not have first hand experience with them. I also have a Fuel Injection Specialties (FIS) harness and it is OK. The ECM can be had used for $10-50. A good external fuel pump will cost at least $100. I use an 88 Ford Truck external pump, $114 from CarQuest, made in Texas by Airtech. If you have a 78-82 you can use your fuel tank with an 82 sending unit and a TPI pump. An aftermarket PROM with VATS and Emissions codes removed will be $100-200 depending on source and complexity. You will have to add an oxygen sensor to your exhaust, $20 for the sensor, $5 for the weld-in bung, and say $25 for an exhaust shop to weld it in if you can’t. Some harnesses use VSS and some do not. An auxiliary VSS sensor is around $75. To install a TPI I say figure at least $800 plus the TPI unit and whatever repairs are necessary to bring it up to useable status. I have TPI/700R4 in my 69 Corvette (Howell harness) and an 83 Pickup (FIS harness) and I love it. Starts good, great torque, good fuel mileage, easy to swap onto stock engines (although both of mine are complete engines out of 90/91 ‘Vettes).

Differences in years
All Corvette TPI intake manifolds work with the older (through 86) iron heads and the factory aluminum heads through 91. F-body TPI intakes use the upright center bolts on 87-92 and thus fit all 87-95 iron heads (non LT1). Either can be swapped to fit the other with some drilling. F-body has the fuel lines come out on the drivers side and has a central port for EGR. Corvette has fuel lines that come out on the passenger side and has an external port for EGR. Corvette fuel rails fit F-body intakes and vise-versa. The runners are all the same through the years, but the LH runner has a hole for a 9th injector in the 85-88 runners. This can be plugged off if you get a nice LH runner and don’t want the 9th injector or decide to run speed-density. The plenums all physically interchange, but 90-92 have an extra vacuum port for the MAP sensor used with the speed-density computers and wiring. 89 is an odd year, it is mass-air flow but without the 9th injector. 89 up throttle bodies can be used on all years, but a 85-88 throttle body requires a ½” hole be drilled in the front of a 89-92 Plenum for idle air. 89-92 Throttle bodies have a bit more desirable cable attachment. The cable attaches around a circular linkage which has a smoother actuation than the straight linkage on the 85-88. The Corvettes have an aluminum plenum extension over the distributor, the F-body extensions are plastic. The Corvettes use an HEI coil-in-cap distributor for 85-91 (Delco 1103680). 85-86 F-body also used a big-cap distributor. 87-92 F-Body used a small cap distributor with an external coil (Delco 1103479). This same distributor is used in the 87-95 5.0/5.7/7.4 TBI injected trucks. The F-body intake gets it's exhaust for EGR from the center passages in the heads like most SB Chevys. A Corvette intake gets it's EGR exhaust from the RH exhaust manifold/header through a flex-tube to an opening near the distributor-no center passages in the intake. If you are required to keep EGR and you have a Corvette intake, I recommend getting the C4 exhaust manifolds. They are like mini-headers, and have a 2 1/2" outlet. I have them on my 69 and like them.

As far as a throttle cable to use, on my Vette, I used a TPI Corvette cable, 1990 I think (about $20 new GM) but you have to cut the end off inside the car and use a hood-release-cable end (Corvette Central 342138 "cable stop") to get it the correct cable length (the housing is OK). You must use a cable from the type car your throttle body came from if you want to have a chance of not cutting it. Again, 85-88 use a straight pull, while 89-92 have a circular attachment for more smooth actuation and so the inner cable is longer. On my 83 truck I used a TPI F-Body cable and it was OK, but I had to coil it up into a loop in the engine compartment because the housing was so long. I also TPI'd a 72 Chevy truck and used a 90 350 TBI truck cable for it. It was 1/2" short outside if anything, but I was pretty pleased with it all told-I didn't have to shorten it. In a Vette it might be about right. In all vehicles I've done you need a die grinder to square the firewall hole off a bit. All vehicles I've done used the late throttle-body.

Why to get it
If all you want is around 300 hp there is no reason to spend a pile of money on a crate motor. The basic $1200 4-bolt Goodwrench 350 with an aluminum intake and a Holley will put out power in that neighborhood. Chevy High Performance (I think) did a series of articles with one of those a few years back and with decent exhaust should get you in that range.

I would look into a TPI. They start immediately in winter, have great vacuum, and will get great mileage. I can open the headlights and the wiper door at the same time with no hesitation at all-solid wooomp. With 3.70 gears (and a 700R4 overdrive) I get 18mpg city and 22+ highway. With 3.55 or 3.36 it would be even better. You can probably find a used Corvette TPI engine for $1000 and with an $800 harness/computer/fuel pump you would be set. On a 78-82 you can use the stock fuel tank with an 82 sending unit and TPI pump and be in better shape than 68-77 with an external pump. With the Vette TPI you would have aluminum heads that would remove weight. Even with an F-body iron-head TPI 350 it will be less weight than a stock intake. It will bolt up to everything in your car, use stock accessories, use your transmission, and the visual appeal is awesome. Don't be afraid of fuel injection, it really works.

As far as websites see:
www.corvettefaq.com for conversions or more TPI info at www.fuelinjection.com

 

thanks for detailed posts. I am really wanting to play with this setup and see what I can get it to do. Only problem now is I cant find the owner of the 79 to see if he is going to still sell it!!

 

Just a fwe other notes here...if you get a TPI setup thats manifold won't match up to your heads (late style F-body on older heads, or the existing engine has Vortec heads), you can always change the base. There are aftermarket bases to bolt up to any type.