c3_dk

Hi,

I've got an ekstra 11:1 comp. 69 Corvette engine that I what to play with.

The engine will be like this:

350 4 bolt std. bore.
TPI/MAP fuel injection.
Brodix 180 IK heads.
COMP CAM CL12-467-8
Rocker arms

I know that the std. ECM is hard to get to work 100%, that is why I am thinking about Megasquirt insted.

Does anyone have any experience with TPI-MAP/Megasquirt?
What Megasquirt ECU must I look for?

Sluger17

Hello not sure if I can help yet but, I am in the middle of a build. What I am doing is a resto/mod since my '76 is not all original or near original ('74 frame, '76 body, 69 VIN, '76 CA DMV VIN). Anyway I pulled the old engine out and bought a '00 5.7L Vortec engine had it rebuilt, sold the intake, and pieced together a TPI system. About a week ago i finished soldering together my Megasquirt board and tested it. I still need a few things to complete my setup but its not cheap (fuel pump, fuel lines, sensors, etc. I dont have the car wired yet because I am still doing body work but I can keep you posted on how it works. I got the Megasquirt unassembeled 2.2 with v3.0 board kit, took about 8-10 hours to put together first time soldering too.

c3_dk

Thanks, please see PM

MonzaRedConvert

Please post your results Sluger. I'm planning a similar project.

baxsom

the megasquirt is an awesome system. i wish i had the technical know how to be able to build one.
supposely about 30 bucks and a trip to radio shack is all you need to control fuel and spark. i was looking into it on my turbo eclipse a few years ago but it was so new not a lot of people were selling already built units.


now a days i would probably just spend the money for the FAST unit myself

c3_dk

Frankenvette

I'm watching this thread also. I have been toying with the idea of a TPI Megasquirt with T5 5 speed tranny in the future. Please keep us updated.

Jim

Gimpy51

I will be trying to keep up with this thread also,have built a v2-bd3 MS and have had very good results(runs a 2.2 l Mazda,efi,and a small turbo)
Hope to get parts together to get a tpi on a 383 vortec,but am dreaming about running ITBs on a tpi base,have gathered some parts,and some info,and am working on the throttle bodies now.(sorry no pics as of yet)
Gimpy51

mrvette

Got news, the MS system used to come with a serial D port ONLY, and if you don't have a olde tyme laptop capable of running the whole thing WITH a serial D connector on back and NOT some aftermarket adaptor, you will find you can not communicate with their computer...

I gave up on a changeout from the stock TPI map/speed density system for the MS some 3 years ago, for that reason...

it's not easy as it looks, support be damned....

NOW if they got around to putting a USB compatible port on their computer, fine, maybe it can work....

programing be damned, you can't access the computer to make changes, you screwed....period...

Gimpy51

DIYAUTOtune.com offers a USB jack that does away the DB9 jack,but I'm using a Radioshack cable on mine and works well enuff.
And your right about easy,it takes a bit of work,but nothing I ever got that was worth while was easy
Gimpy51

mrvette

Almost 4 years ago now, that was not available that I knew of....DIY AUTO tune was my dealer too, no help, they tried, but engine would die soon as it went closed loop off idle....

I was on the rong trail anyway, the stock computer 1227730 and chips were NOT at fault anyway....

c3_dk

Regarding DIYAUTOtune different computers, what is the best choice for my engine?

350 4 bolt std. bore. (L46 engine block)
TPI/MAP fuel injection. (1990-1992 Corvette)
Brodix 180 IK heads.
COMP CAM CL12-467-8
Rocker arms

I am also thinken about a 5 speed tranni, what is the best choice for my engine? (TKO 500 or 600)

c3_dk

Also is there anyone that can burn a new chip for me, if I tell them my engine setup?
(If I decide to go with my old ECM unit)

mrvette

http://www.pcmforless.com/

Did mine some years ago, turned out all my troubles were due to a gallon of water in the bottom of my tank, that and the injectors in the engine needed changed to Bosch, and not the 5-0 Ford injectors....

Gimpy51

I'd use the MS2,more options,and you can run the spark from a 3d map,and set it up with msextra firmware.Wouldn't need the MAP,MS is a speed density setup.As for the trans.if your not using an electronic controlled auto your set.
Gimpy51

autoist

I'm about 2 weeks from dropping my '86 TPI into my '77 frame....so, this thread has my interest.....any how to tips, photos, etc. would be helpful to lots of us.

I'm planning on keeping the original injection system but am interested in how you pressurized the fuel system - pump, lines, etc.

markdtn

Here is 1 version of my TPI "primer". I have another with LT1 info too.

*********
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 (discontinued now from 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.

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

autoist

"I use an 88 Ford Truck external pump,$114 from CarQuest, made in Texas by Airtech."

Where'd you locate it?

How did you utilize your stock gas hard lines?

Will the '77 tank work?

Have had your write-up copied for some time & am reading & rereading trying to get a grasp of it....I've someone who'll redo my harness & PROM so that's not a concern of mine. I'm removing all emmissions from my car & the '86 engine.....to include the cannister & its return line to the tank. The questions above, though basic, are where I'm stumped.

mrvette

Those external mounted pumps are all about the same, about 1.5" dia and ~6" long, input on one end, output and power terminals on the other, I just wrapped mine in some radiator hose, and clamped to the rear frame rail on my '72, right under the tank output....I used the stock lines for both supply and return, work fine for some many variations of the install and ~400 hp, for some 15 years now, no need to change HARD lines, the hoses should be something reinforced steel from like Aeroquip and use FI rated clamps...

markdtn

I think you can buy the same pump from O'Rieleys now too. I located my pump above the frame on the right side. I have the rubber line from the tank going into it and then I went to the junkyard and got a Ford fuel fitting for the other side. I carefully cut the plastic hose off and attached the Ford fitting to the hard line in the car with high pressure FI hose and proper clamps. On the other end, I got the stock front lines from a C4 and grafted them in. You really should get hydraulic unions and not use low-pressure brass unions. If you don't have a C4 pipe, you can use stuff from many GM FI cars. I think on my truck I used 3.1 Corsica or Lumina pipes and rebent them some. The 77 tank is similar to a 69 tank except the outlet is on top. It should work fine. If you have any more questions, please ask. TPI is almost old school now, but is hard to beat for just a good driving, reliable FI setup.