fuel inj..

[caspear78]

is any one runnin any fuel injections on thier trucks , and how much of a diff has it made going from carb to fuel injection, has it increased your gas milege at all

[FRENCHBLUE72]

Board member BOBBYK has done the swap you may want to p.m. him if he don't anwser here..

[tomsC10R]

I'm going to be running Holley MPI. Should be done in a few weeks. Won't be able to comment on mileage improvements because I only drove the truck maybe 3 times before I tore it apart for winter. I'm not sure if you were thinking of buying a complete system or what... I bought my MPI Projection system over Ebay from a private party, never used. Very complete kit, but pretty pricey new. I didn't pay a whole lot more than a new intake and a good carb would have costed. Goodluck.

[71gmcfanatic]

The way fuel prices are going i may be switching to FI also. Most likely the holley tbi system or a used gm tbi system. Does anyone have any experience with the holley tbi?

[RON WOODGEARD]

I have known a couple of guys change over to fuel, TPI,and or Tbi.. The newer Holley kits work very well.

Yes you will get an increase in mileage. how much is hard to say.. Either go to a wrecking yard for everything you need, or watch E-bay, when I was seriously considering it, I watched ebay, there is a lot of them there. Just remember you need to match the donors computer's output to the H.P. of your engine, It really is a great way to go.

Check these web sites out for more info.

http://www.autoshopracingengines.com/fuel.htm


http://www.chevythunder.com/index.htm

[BobbyK]

Ya I did mt TPI swap about 3 years ago now.
Definite increase in low end tourque.I gained maybe 50miles more to the tankfull,better drivability,quick startups.
It was win win in my case.

[Faster_than_you]

if your going to get a gm tpi set up. try get the 87-88 corvette, or 89-90 camaro setup. In the books I have read supposubly they have been the ones that produced the most amount of horsepower, and the most reliable. In my vette I recieved about 27 mpg at 55, and 21 mpg at 95. I usually got 21. I sold the car on valentines day this year, with 126k on it, never had a problem with the tpi. I installed 40 lb injectors I think that was the size. was 4 years ago I did that.
anyways, I would say injection is the way to go.

[caspear78]

so would i have to rebuild my moter for a mpi setup or is it just bolt on, as in the intake and such from there up

[jmanz69]

If you go with a TPI setup from a later model, like the 88-92, then you will either need to have the manifold modified or have new heads to accept the intake. The 4 center bolt holes are at a different angle in the later year TPI. The aftermarket MPI should bolt right on. The real question is this. How long will it take to recover the cost of the FI with the savings on gas. The answer varies, but is usually around 4-5 years. If you use it as a daily driver, it will be less, but if it's a sometimes driver it will take a lot longer. I would maybe think about changing your rear gears if you want more MPG. Would only cost a couple hundred dollars, and mould make a bigger difference. I am going to TPI because I want the quicker throttle response and better torque, not for MPG. It's my toy car, so it doen't need to get good mileage.

Just something to think about.

[Bowtie67]

MPFI is the way to go if you are looking for best MPG, There are some limitations with the GM TPI for all out performance, RPM band is limited. The TBI setup as well has it's limitations as well, There are only two injectors so High HP is not associated with TBI units. Holler makes a Projection system in many flavors from a 2BBL to 900CFM 4BBL. There are several manufacturers out there that offer FI. I have been unsing Holley setups now for about 5yrs. My last setup with a hipo 350 w/10.2cr and 700R4 w/2200 stall and 3:73 gears I averaged 22mpg Highway and around 17city. I have not fired up my new engine 414SBC and the new Holley StealthRam setup. I am hoping in the next couple of weeks to finish up all new rewiring, Rear Suspension and redoing the interior.

[Shane65]

While not in my truck, I put on a Hilborn in my Chevy II and converted it to efi. Works and looks excellent. Gas mileage is better then the Eldelbrock dual plane intake I had before. I have another one that may end up in the 72 GMC but that's a year or two away(I got too many things on my plate).

[RON WOODGEARD]

Originally posted by caspear78
so would i have to rebuild my moter for a mpi setup or is it just bolt on, as in the intake and such from there up

You do not have to build a Motor for the Injection unit... You build the injection for the motor..

If you're running a stock rock smallblock, then an injection unit off of any regular car/truck will work. But if you have it boosted a little H.P. then the Trans-Am, Corvette, Hi Output Camaro's and the such work.
The one website I listed above is very descriptive, and helpful with what unit to choose for what engine output.

Just do some research. you'll learn some good information.

[RON WOODGEARD]

Originally posted by Shane65
While not in my truck, I put on a Hilborn in my Chevy II and converted it to efi. Works and looks excellent. Gas mileage is better then the Eldelbrock dual plane intake I had before. I have another one that may end up in the 72 GMC but that's a year or two away(I got too many things on my plate).

Shane,

Dynamite setup !!! And welcome to the site.. This is a setup I have considered running since the 60's... Air cleaners are the only thing that stopped me.. And I have alsways lived in the boonies, generally dirt roads.. I bid on a complete belt driven setup on E-bay from Canada a year or so ago.. But I got sniped..... How did you do the conversion??

By the way,, Let us see some full shots of that Nova...

[Shane65]

Here's a shot of the removeable air cleans I made out of stainless steel. I topped them off with K&N's. I can remove them in 10 seconds without any tools.




Here's a link to some pictures of my car.

http://groups.msn.com/SNS2/65shane.msnw

[RON WOODGEARD]

Originally posted by Shane65
Here's a shot of the removeable air cleans I made out of stailess steel. I topped them off with K&N's. I can remove them in 10 seconds without any tools.




Here's a link to some pictures of my car.

http://groups.msn.com/SNS2/65shane.msnw

*****en Car !! Nice interior job.. But I missed the air cleaners..

[caspear78]

i love the pics of the setups, now i get to drool over them until i get mine setup,lol

[Perchjerker]

Not to sound like a aszhole, but if I wanted better gas mileage I would drive a different vehicle. I save my carb-ed Chevy truck because, well, it isn't FI like most vehicles you see on the road now. Also, I can mess around with it and tune it like I want it. I just don't see any justification for changing your antique vehicle to meet todays standards. Isn't that the point of owning an old truck?

[RON WOODGEARD]

Originally posted by Perchjerker
Not to sound like a aszhole, but if I wanted better gas mileage I would drive a different vehicle. I save my carb-ed Chevy truck because, well, it isn't FI like most vehicles you see on the road now. Also, I can mess around with it and tune it like I want it. I just don't see any justification for changing your antique vehicle to meet todays standards. Isn't that the point of owning an old truck?

thought the idea of owning a vehicle old or new, was transportation,, but along with that transportation is the idea of being able to play with it, and that involves doing whatever trips our triggers,, You can play with Fuel injection just as you can a Carb. I can see a lot of justification to updating,.... It's called having fun...

[jmanz69]

There is nothing wrong with updating, In fact, it will be fun to see what I can get out of the TPI. But, I don't think anyone should think of switching to FI to save money. The cost involved is the switchover is too high to make it worth it unless you do a lot of driving, and I mean A LOT. It's a switch to do in a toy car, not your daily driver. Yes, it will help with mileage, but not in a dramatic way. You aren't going to go from 10 MPG to 30. Just have fun with it, and do what you want to. It's your truck.

[71Blazer]

You do not have to build a Motor for the Injection unit... You build the injection for the motor..

I installed a TPI unit from an 86 Corvette in my 71. While it is true that these intakes are direct a bolt-on for any small block I have to say there are a few key factors that will make or break the project... at least it did for me.

Cam overlap is extremely important. I have a Comp Cam HE268 which has a barely noticeable lope at idle and worked great with a carburetor. However the overlap for this cam is 110* and didn't allow the air to flow properly.

Displacement turned out to be a concern as well. My small block turned out to be a .060 over 400. At 413ci the TPI couldn't flow enough air to keep up with the engine.

I had an ACCEL DFI computer so all parameters for air and fuel were totally programmable but the basic problem was the intake and engine were a mis-match.

All the problems I encountered could easily be solved with more time and more money but I ran out of both.

So to make a long reply short; the intake and engine were mis-matched. I learned a lot over the course of this project. And it went something like this: re-install carburetor

[454_72_4X4]

I'm new here too but I just have to chime in here.
I've been thinking about the FI swap thing for a few years now. I'd like to do both of my trucks.
(72 454 and 87 S-10 35)
I've got a complete TBI setup from an early 90's motorhome (454), and a TPI intake / computer from a 1990 Camaro (305).

First the 72;
By complete TBI system I mean everything right down to the ignition switch and the key. (The best part is the motor home used the same style indash switch as my 72!!)
The only wires that were cut are the ones that go to the fuel pump/sender.
My 454 specs;
Basically a stock rebuild
(.030 over TRW forged flattops)
Comp Cams 268H
and (hopefully if I can find one) an Edelbrock Performer intake

Questions;
1. Would the forged pistons cause to much noise for the knock sensor on the TBI?
2. Would the cam be compatible with the stock ECM/prom?
Right now I can't really afford to have a "custom" chip. So would it run with the stocker? I think it would run but maybe not be "perfect"?
3. How hard would the actual installation be? By this I mostly mean the wiring and possibly the fuel pump. I've got a fuel tank from a mid/late 70's Surburban that I'd like to put under the truck also.
4. Has anybody did this to show me some pics?

Now the S-10;
All I have is the intake and computer. I know I have to have a wiring harness.
Questions;
1. Where/who to get the best/cheapest harness from. I've looked at the Painless harnesses in Summit and Jegs but I don't know how they do the VSS and VATS?
2. How would I do the VSS since I run a NV3500 5 speed and have no way to hook up the speedometer?
3. I know my curent cam is to big to run the TPI with. (Comp Cams EX268H), cause it carries around 11 inches of vacuum at idle. Looking for cam recomencdations.

Enough for now! Sorry for the long post but any help is appreciated.

[jku72]

I put a holley Pro-jection system on my 67 Catalinas 455, and it works great. Excellent throttle response, so easy to optimize with a laptop, engine starts immediately, I'm happy with its performance. For what I use the car for, it is what I want.
That being said, as I build my 68 burb into my daily driver, I don't think I'll inject it. The truth for me is that the cost of the unit compared to the return is not justified for the purposes I need. By running a well tuned Qjet, I get good mileage, and although fuel injection might pick up a mile or two per gallon, for the 2 grand that a complete system installed would cost, it just isn't worth it. Especially when you consider maintenence of parts. The fuel pump for a 350 is 15 dollars. A whole new carb is $300, and a rebuild kit is $30.
I like the simplicity of the stock carb setup, theres not a lot of thinking involved with trouble shooting. If there is a problem with the fuel injection unit on I-95, I'd have to call a wrecker for sure.