I am toying with the notion of installing a TPI on either my 67 or my 75 ( or maybe even both). I'm sort of leaning toward the 75 due to the tach drive issue.

One big issue is the fuel pump. I know that a pump in the tank with a return line to the tank is the recommended way to do this. My question: If an inline pump were installed back near the tank inside the frame, with a return line run to the suction side of the pump, would it work? Are the electric in-line pumps gear pumps or centrifugal? I have delt with all types of industrial pumping applications for many years, and my gut tells me that such a rig would work, at least in theory. Wondering if anyone has tried such a setup. It would sure make the install a lot less painful. Any first hand experiences you can share would be appreciated.

 

Hi, I have completed several TPI conversions in vehicles other than Corvettes. In a couple different projects, we used inline pumps. The pumps are pretty common in various foreign cars. You need a minimum of 45-50 PSI for a TPI. I believe the pumps are vane type and are pushers. The pump has to be mounted close to the tank so it can pick up the fuel. The pump can't pull or lift fuel a long distance.
We used the fuel vent line to the charcoal canister as a return line to the tank. Fuel delivery is the biggest issue in the conversion. A return line into the suction side of the pump line might create an areation condition in the fuel which could lead to cavitation in your pump and the engine could starve for fuel. I would opt for a dedicated return line. It is necessary to either baffle your tank around the fuel pickup or keep your tank relatively full. I have an El Camino without a baffled tank. With low fuel, acceleration or curves can cause the fuel to move away from the fuel pick and cause a momentary fuel starvation. The engine will lose fuel and stall until fuel is picked back up in the tank.
I have seen a setup that incorporated a fuel block on the suction side of a an inline pump that allowed the return line to dump it's fuel into the block. Not sure of the exact position of the inlet, outlet and return fittings. The block worked but was bulky and looked tacky! With the space limitations on a Vette, I believe that a direct line back to the tank would be best.
A company named Jags that Run published a great reference book on TPI, TBI conversions. The book had information on alll aspects of a conversion including speedometer conversions, pumps, fuel delivery, air cleaners, etc. A great book for reference.
Please contact me via E-mail if you want more info.

 

62fuelie:

I installed an inline pump in my wife's 62 with the Ram Jet MPI system. I used the tank drain for the outlet to the pump and the stock outlet line (into the top of the tank) for the return. I don't see any reason that routing the return line into the input line should not work. I guess it would depend somewhat on the size of the pump feed line and how much pressure was in the return line. I would think that the less restriction in the return line the better. If placing the return line into the pump inlet caused some type of problem, you could always add a small sump tank just ahead of the pump and route the return into that.

Charles

 

Hummmm. gotta go look at the AIM. The 75 may already have a return line in place. I don't think the vapor cannster is hooked to anything these days, but I guess the return line is still there???

 

Well, If I had taken the time to look at the time to look at the AIM, I would have answered most of my questions. The 75 already HAS a return line to the tank, in addition to the vapor return line (which is apparently a hose). It down side of all this is that the lines close to the tank are on top of the frame, and it would be difficult/impossible to get an in-lne pump any closer to the tank than about half way to the engine. Since these type pumps push a whole lot better than they pull, that probably wouldn't work very well. Looks like an in-tank pump is the way to go, but there is no need to run a return line and have to lift the body, etc. That would still increase the PITA factor considerably.

 

I'm in the process of installing a TBI on my '65/400sb. It has run but the TBI system will need some reprograming. That will be my next exercise. I have not driven the car due to snow. The fuel pump I am using and is quite popular for FI conversions if a ford truck frame mounted late '90s fi pump. I mounted mine cross ways on the rear crossmember and used the original supply line. The pump is right below the tank so there is a good gravity feed supply. That gives you plenty of room for the inlet and outlet filter. I was able feed a return line down the frame on top of my feed line. At this point I have the return line "T"d into feed line before the pump, but that is subject to change. I just thought of something. Will a Cross-fire C3 tank fit in a C2-C3? That would give you the pump, baffle, return line you need. Though you would have to change to a higher press pump for TPI. They require higher press then TBI.

 

I have been running tpi for about 10 years and the only major trouble I ever had was when I first installed it trying to use external pump. The whole key to making a modern fuel injection run correctly is to have the correct and constant fuel pressure. Most of the guys that I have known trying to use external pumps have given up and put the pump in the tank.

You can send your tank to Rock Valley and for about 300.00, they will install a new pump with a baffle around it and return line connection and wiring. Also if you can find a 82 tank, all you have to do is change the pump. Good luck SSS

 

SSS, Does an '82 tank fit in a C2? I have heard of quite a few guys using this ford pump with good results.
I bought the JTR manual. I was dissapointed. I don't feel that it instucts one how to install TBI/TPI into an older vehicle. It does however, tell one how to install an TBI/TPI engine and trans into jags and volvos and such, and the goes on to tell what books to buy to make it work. Hmmm. Incidently I am not the one who wrote the letter to them stating such, that they published in the next edition in a belittling way. I did contact them about that and that I agreed entirely, they replied that they would remove that fellows letter from later editions. I do say that they have done a LOT of research into the subject and there is lots of good info there about the VSS and fuel line needs etc. They also sell a very handy VSS unit that many need. I think I would still buy the book but it does not tell one how to install TBI/TP into a car as it would lead you to belive.
My next procedure is to reprogram my ECM prom. If anyone has experience with this I would like to corespond with them.

 

Also if you have not seen this site:
http://www.chevythunder.com/index.htm
Check it out, It was by far the best resource, once I got at it, I had for my project even tho mine is TBI and this site deals with TPI.

 

oofxd I am not sure if a 82 tank fit a midyear ,the reason I know how slick a 82 tank is because I have a friend that put a tpi in his 81 and all he had to do was drop the new fuel pump in the top of the tank and never had any trouble. I had to learn the hard way by trying the external way with some success but never making it work correctly.

Street and performance has always helped me with any problems I have had with my tpi , most of the problems I have had have been my fault. So far I have put about 75000 miles on my tpi unit. SSS

 

Just as I was posting my first post it struck me. A "Cross Fire" tank should be just the thing.

 

78-82 tanks are larger with a more rearward fill- because of the 'fastback' configuration. The pump & sender will probably work, though.

 

Thanks MassVette. Good thought. Does anyone know if the Sender/ Return/ Feed lines are all together in an '82 Corvette with "Crossfire Inj", and will said assembly fit in the Mid year "Bung"? I'll bet it's a bigger hole.

 

00fxd,

Try Racetronics, I have seen their banner displayed on this forum. I have known them from the buick turbo 6 forums, I have contacted them about converting a c-2 sending unit/fuel feed to hold a fuel pump and run the return line back into it. They say they can do it. I plan on going with Rock Valley so you have the baffle included also ($800, little more money but will be a complete bolt in tank) . I am going to install a buick grand national v-6 motor and 200r4 tranny in mine. Plan on running the return line along side of the framerail. I have been working with Buick GNs for years I would definitely go with the intank pump.

For reprogramming your chip you should check into Tuner Cat. They have software for alot of different models and puts in into easy to understand tables. If your really understand editing the chips I would look into a Pocket Programmer II, it should come with an editor and will allow you to change more parameters then the Tuner Cat. But if your new to it, get the Tuner Cat and make small changes till you understand it other wise it you trash your engine. I use it to tune for the v-6 turbo chips. It helps alot to tune to each car. You can buy aftermarket chips but I have picked up 30 extra hp over an aftermarket chip. Each engine is different. I have seen 8 degree in timing difference on the same setup in different cars.

Chuck

 

Thanks Chuck;
I was under the impression that:
http://winaldl.joby.se/
would be the program I would need. That, a lap top, interface cable, and a burner and I would be set up equipment wise. Am I on track? I haven't done this before but there's lots of stuff I've never done before. Don't wanna trash any engines tho.

 

00fxd,

Actually that is just a scaning tool. It tells you want is happening. Does Not let you make any changes to the chip. Also when using the aldl port the data stream is slower then straight of the board. On the buicks we have Direct Scan which gets the data right off the board (18 frames per second). You will need a scanning device to know what changes the chip needs. The tuner cat will let you change tables such as PE vs Rpm (fuel trim), Timing tables, Boost Scalar (if running turbos or supercharger). Once you change the tables and save the bin. file you will use a burner to burner that program into a chip. Also you need a chip eraser so you can use the same chip over and over. The chip need to be blank to burner the new program. Once you under stand that then we can move you up to a thumbwheel chip which holds 8 or 16 programs on one chip. That way you just click the selector and change programs from a theft program that shuts off the injectors so it won't start, have one for pump gas, one for race gas, one for gas mileage, one for emmissions if needed, and for for nitrous.

Go to WWW.tunercat.com

They have downloadable samples of their program, so you can sample play with the tables and see what is available.

Main tables you should be concerned with are:

Ecm Constant-- set fuel shutoff, injector rate, electric fan on/off, and others

Timing maps- set your timing vs load vs rpm

Pe vs Rpm-- fuel curve

feel free to asking me any questions after you download and check it out.


Chuck

 

oh, I forgot the valet setting also. Just in case you have so one work on your car or your wife drives it. You can set up the injectors to shut off at 3000 rpm or/and 55 mph, if running turbos have the boost limit only 3lbs so they get to feel what it could be like but not the full effect.

Chuck

 

Thanks Chuck, No question, there's a ton of cool stuff I can do once I learn how. I had a look at tunercat. Could you tell me what on that site you're suggesting I download and look at. There's a lot of stuff on there.
To erase the prom, how intense does the uv light have to be?
Thanks, Frank.

 

good info

 

Frank,

It depends on which Fuel injection and ECM you have. Try this site out

http://bmcomputersource.com/Qstore/t6tuner.html

it has the a the buick tuner program for 30 days free. You need to download the stock chip image-

ACXA0942 Image

that will give you the stock chip image to modify and see the tables, depending out your setup tables will vary a little but it will give you the basic. Again check this table: ECM constant (injector constant- setting basic fuel: fan shut off and on - temp & mph if running electric fan: Blm -high and low allow computer to add or take away fuel according to O2's: Rpm limit, mph limit, Idle rpm- let you set the idle, Torque Conveter lockup and unlock if your a lockup converter), timing maps (show 2d and 3d adjust for load and rpm), Pe vs Rpm (lets you fine tune the fuel curve),


As for eraser they are pretty cheap $60, it uses a uv light (not sure how powerful) to erase the chip. The chip is usually in a carrier (plastic). you will have to remove it from the carrier (they sell a tool to make it easier to remove). I remove it by GENTLY squeezing the prongs inward. The chip is held in by the prong fitting into the grooves in the plastic. Be careful, if a prong breaks off it is no good. You might break your first one or two but once you've done it, it's quite easy. Once the chip is out of the carrier you remove the sticker on top which covers a window to the chip. If you leave the chip uncover and in the sun for a period of time it can erase some of the program stored. After the sticker is off you put it in the eraser for 2 min if it's the standard chip, thumbwheels take around 10 min. ( more memory takes long). If you look at your chip it should be a 2732a chip (standard chip).

This site sell the whole kit to burn chips for around $250 (without scan tool). If you contact Tuner Cat with your ecm and fuel injection setup they will tell you which program you need.

Chuck