I sold all my old tpi stuff to help pay for the conversion.

 

Why do you say this?

 

 

Heh, no, not a personal attack, just a general observation.

I was thinking about car magazines, mostly. The advertisers probably pay the writers to villify the old stuff to make their products look better.

I like old-school 60's cars (even though I'm just 24) and sometimes it gets frustrating seeing magazines where the old tech stuff is bashed and insulted over and over and over.

In a way, I even think its a slap in the face to the people who designed and built those cars.

 

During cold start a carburetor allows LOTS of raw fuel into the combustion chamber. This fuel ends up in liquid form and washes the oil off of the cylinder walls.

This is DRASTICALLY reduced with FI for several reasons. First the engine almost always starts immediately. Secondly due to the high pressure on the injectors, IAC and the cold start injector when equipped, causes very good fuel atomization which allows the fuel to be burned rather than end up on the cylinder walls in a liquid state.

Additionally due to much better fuel management, mostly in closed loop mode, it is very uncommon for an engine to experience lean conditions that produce ultra high combustion chamber heat, resulting in burnt valves and other damage.

Our engines started lasting much longer when fuel injection came into use. This is not a coincidence. I have heard people give all sorts of reasons for modern engine longevity including; better oils, more precise machining, more advanced materials,........ The reason most responsible for todays long lasting engines is fuel injection for the reasons that I described above.

Have a great day,

 

When I was your age I DEVOURED car magazines, mostly Hot Rod, Popular Hot Rodding and Road and Track. For whatever reason I don't do that any more.

I don't know which mags you read, but I am really surprised that the Hot Rod type magazines bash carbs because the Hot Rod community is the only market that is left for them. It would seem that they would have a number of advertisers selling carbs of all descriptions.

I don't see bad mouthing of carburetors as a slap in the face to us old codgers. The carburetor was the best that could be offered in its day. If those same engineers had been presented with todays technology they would have come up with similar solutions.

I still like sixties muscle cars as well. I had some dandies in the late sixties, early seventies including a 64 Galaxie 500XL 427 car, a 68 road runner, a 67 350HP 327 Vette, a 40 Ford Coupe with a Z28 350, and a 23 T Bucket with a 6-71 blower on an SBC. All of these cars were four speed except for the T Bucket. I lived the era and it was great, but todays technology totally eclipses it.

If I were like most people of my age I would probably be telling you that "fuel injection is junk, give me a Holley." The reason I am not of that opinion is because I am an electrical engineer so my computer/electronics knowledge along with my knowledge of carburetion has allowed me to understand electronic fuel injection quite easily.

Thanks for your comments about the magazines and your reason for your thought process.

Have a great day,

 

thanks for all the replies guys, Im still about 90 percent sure i will be swapping over to carb.

Alot of you make great points, and i can understand carbs are not for most people. And are definately inferior to modern efi.

realistically though, My vettes tpi is not modern, and system has seen better days, and its reached the point that when i fix one thing, it just reveals another porblem. And lets face it, hands down, a stock tpi system is no match for a proper carb setup in terms of hp.

Im 22 years old, and struggling to afford my 360whp subaru sti, im just not financially able to replace , all the odds and ends on the vette. I always wanted a vette, and i want to drive it, not throw money and look at it.

 

Hey, go for it! Carbs causing engine life to decrease? get real, there are alot of old chevys with carbs still running today and I can personally say I've had a few with over 100,000 miles on them that were still strong and burned very little oil, know what leaky injectors do?If you're looking for simplicity and Max power-the carb is the only way to go.I agree that EFI is great for street driving, and more fuel efficient-but look at the the max side and almost all are carbed. When I built my 64 I did my research as far as CFMs-what I was surprised at was my highly modded engine performed best with a 650 double pumper 4 squirter than with a 780-both Holleys-which in my opinion are one of the simplest carbs to work with.Alot of guys here have went with carbs-but everytime someone asks the question-it's like "are you nuts"! And a well tuned carbed engine should pass emission testing with no problems-unless your state prohibits engine modifications!

 

Okay fella, if you're happy with 100,000 mile engine life then I say go for it. But since it is obvious that you are not aware of this, 300,000 miles is common engine life for a modern, properly maintained FI engine and I mean of most any brand.

In the sixties and seventies we considered 100,000 miles as kind of a normal maximum engine life. Now days if I were to buy a car that I could not expect 300,000 miles from the engine without major work I would consider myself COMPLETELY ripped off.

I agree that if your number one goal is absolute maximum power, on a highly modifed engine with racing in mind, a big intake and big Holley are the way to go. BUT I CAN PROMISE YOU that if this is an engine that gets driven daily or frequently it will exhibit ACCELERATED engine wear, as compared to an FI unit, due to raw fuel washing down the cylinder walls during cold starts.

Now, if you are still convinced that you can get as much engine life with a carb as with FI, tell me, what is YOUR explanation for modern engines having such drastically increased life if it is not fuel injection?

Have a great day,

 

tsiawd,

You seem like a good, hard working guy to me. I grew up without any money and had to work my way through school and pull myself up by my bootstraps, so I can relate with your trying to make every dollar count.

I wish you lived close to me, so that I could help you get your FI sorted out. I just hate to see you do such a downgrade on your car.

Until you learn more about your FI system and how to deal with it, I totally understand how it can appear overwhelming. Once you understand it, the problems are usually simple to figure out and usually not ridiculously expensive to fix. A REALLY good book on your L98 FI is "How to Repair and Modify Chevrolet Fuel Injection" by Ben Watson and published by Motorbooks International.

Since you have decided to go ahead with this, I would make one suggestion. Be very careful about how you remove the FI unit and wrap everything in plastic bags and box it up to keep. Disconnect your electrical connections and tape them up with electrical tape and use tie wraps to tie them back out of the way. Where you need to tap into a wire in the existing harness, make a connector that will plug into the original connector rather than cutting and splicing.

Do NOT just start cutting wires and throwing everything aside. Not only would this approach cause lots of possible problems even with the carbureted car, but also will make it near impossible to retrofit, thus potentially drastically decreasing the value of the car.

Remember that the engine computer controls things OTHER THAN the fuel injection. Things as simple as the cooling fans are run by the ECM. You really need a factory service manual on hand so that you can sort all this out as you go.

Finally, and please don't take this the wrong way, I am surprised that a younger person is doing what you're doing. It is usually an old codger like me that says "the heck with all this new fangled fuel injection, there's nothing like a good old carburetor." Resistance to change is a normal human trait, but you have to know one thing before something different can be considered change. The old guys that learned point ignitions and carburetors are often stuck in that world, but it seems unusual to see it go the other way for a young person.

Best of luck with the conversion and please keep us posted on your project.

Most of all, I expect that like many of us here, messing with cars is a hobby, so take your time, think it through and enjoy whatever car project you have your hands in.

Best of luck with it,

 

Check out MSD's site for a somewhat new distributor they have out. It uses dials under the cap to adjust the timing curve. This will save you a bunch of trouble when fine tuning your combo.

As far as other parts, you have 9.1 inches from the block to the hood in the current TB position. Maybe a smidgeon more where a carb would end up. This is measured from the lifter valley crossover, front of the block, and comes from forum member jburnett who builds custom intakes to fit under stock C4 hoods.

Now, should you, I wouldn't recommend it. For a track car there are a lot of things you can ignore but for the street you will need to be careful what you remove. Some rewiring may be needed for other systems. Your ECM may not completely go away without the same amount of work/time/$ required to repair/upgrade the efi.

Good luck whatever you do

 

thanks for all the comments guys. alot of people seem to think, im doing this because of a lack of understanding of efi. thats not the case, i completely understand efi , and tpi is a very simple efi system.

 

You know I had one other thought that was triggered by RainDelays post. If you leave the ECM in place which I believe that you will have to do in order to run some of the other functions, you will be living with a constant Service Engine Soon light.

Good luck,

 

Luckily early C4 ecm's were as close as you get to stand alone. Mine is completely out (running DFI w/dual sync dist) and the only thing I lost was AVG/INST MPG on the dash.

87 ecm is diff't than the "one-off" 85 but probably isn't much more involved. Certainly nothing like todays serial, and beyond, links.

 

Tsia, I converted my 86 to carb. I put on a greenwood hoodscoop to accomodate my intake/carb combination. Let me know if I can help ya.

 

I wish you lived close to me, so that I could help you get your FI sorted out. I just hate to see you do such a downgrade on your car."

mine is carbed and i love it. why did i do it to begin with ? One day without even touching the car ( the motor) it ran like crap. Gave a code and guys here were helping me track it down. I even had the entire dash out of the car checking some bread box thing on my 85. So 3 weeks of 11 PM till 3 Am working on this thing and finally finding that the MAF plug ALL OF A SUDDEN decided not to make a 12V connection. I was not happy. Same problem as you, all the wiring was just old, and i said no more.



Add it up guys holley 750 VS with elec choke $250, fuel pump with return reg. $200, stealth intake $115, drop base air cleaner $ 50, stock HEI from autozone for 1978 Camaro $80. PROJECT DONE. Use the stock fuel lines and run a return regulator, the pump will mount right to the spare tire hanger. Get the proper TV cable and holley bracket for the 700r-4 and it really is that simple. Use the stock fuel pump positive wire to run the new pump.

EFI with tuning 9 chip burning, etc.etc.etc.etc.. 4-5K

I drove my car ALL last winter in Northwest , IN. it gets 26 MPG on the hwy, starts no problem in the dead of winter and does run better and quicker than most the upgraded EFI stuff i've see.
Now as i've said many times before i would NOT change an lt-1 to carb, but the L-98 is just too expensive to upgrade.

Mike

 

Mike,

This sounds like a really good deal for the both of us. I am totally happy with my TPI and would not DREAM of changing it and you feel the same way about your carburetor.

A Win-win!

Have a great day,

 

I completely agree with you mike. Hows the difference in performance? Also, did you order everything from one place? Any reccomendation where to purchase? also What fittings did you use to plumb the fuel system and what parts are you using?

thanks alot.

 

Obviously MB hasn't experienced a well tuned carbed engine-and if the carb is set up right your NOT going to be washing cylinders-and MB, if you read this-then re-read what I said-over 100,000 and still running strong with little oil consumption-and what I said about FI. I'm sure you can find MANY carbed cars still out there running great with over 300,000! Ever hear any one with leaky injectors-talk about washing the cylinder walls-same principal-good equipment and no worries.Relax dude and lose the flame.

 

"Obviously MB hasn't experienced a well tuned carbed engine..."Rick Lambert

Okay Rick! If you think that I have no carburetor experience let me give you some background.

The first carburetor that I made right would have been 42 years ago. People that have known me over the years know how well I am with carburetors and seek my advice on same. When carburetors were the only practical choice I ran some engines WAAAaay past 100,000 miles, but those were mostly highway miles with very few cold starts.

I have dialed in hundreds of carbs and rebuilt as many. How much experience do YOU have with them?

Even a carb that has the choke and everything EXACTLY correct is introducing relatively large droplets of fuel into the cylinders as compared to the fine mist of injectors or cold start injectors that have 40 plus pounds of pressure behind them.

I have also disassembled lots of engines and you show me a carbureted engine that has gone 300,000 miles and I am QUITE sure that I will show you one that has seen lots of hiqhway miles with a minimum number of cold starts and it is HIGHLY likely that it no longer has the original carburetor unless the throttle shafts have been rebuilt and other major work has been done on it. I have believed most all my life that if there were a way to keep an engine warmed up and still keep the oil changed it could run almost indefinitely.

Yes indeed, an injector stuck open will indeed cause wear problems but how often does that happen? Most injectors that I have seen fail have stuck closed. Additionally when that happens the FI engine sets a code and calls even a non mechanical drivers attention to the problem. With a carb, some people MIGHT head the warning of worsening fuel mileage, but many drivers are too ignorant of the mechanics of a car that they just don't know the difference. (This is not an inferrence that you fall in that category. I am talking about Mr. Average motorist.)

Okay, now I ask you the same question that I asked before, plus one additional question:

1. If fuel injection is not the main cause for very high engine life in the cars of the last 15 or 20 years then what is YOUR explanation for such a dramatic improvement?

2. How much carburetor experience and engine analysis experience do YOU have?

Since you did not dare answer my question from the last post, will you dare to answer these questions? Hmmm?

Have a great day,