L98 TPI to Carb
03-30-2009, 12:02 AM
#44
Team Owner
From my personal experience with carb and EFI I think they both have their pros and cons.
EFI is great because of the gas mileage and ease of tuning without taking anything apart like the carb, I know this is more easily achieved with newer EFI systems. The carb is simple yet effective, period. Out of all the cars i've owned my '77 Chevy C10 was the most reliable, never once did it refuse to start unlike EVERY single newer car i've owned.
IMO the early EFI systems like the TPI are garbage next to a carb in terms of reliability and power. If I didnt have so much invested in the TPI I would switch no question. However, I would rather transplant an LS1 or something of that nature instead. More efficient than any previous system.
EFI is great because of the gas mileage and ease of tuning without taking anything apart like the carb, I know this is more easily achieved with newer EFI systems. The carb is simple yet effective, period. Out of all the cars i've owned my '77 Chevy C10 was the most reliable, never once did it refuse to start unlike EVERY single newer car i've owned.
IMO the early EFI systems like the TPI are garbage next to a carb in terms of reliability and power. If I didnt have so much invested in the TPI I would switch no question. However, I would rather transplant an LS1 or something of that nature instead. More efficient than any previous system.
03-30-2009, 07:18 AM
#45
Instructor
I think this is an OBD-1 problem, OBD-2 reports exactly what is wrong, spark plug 3 misfire, compared to misfire. All OBD-1 tells you is something is wrong in a circuit, making troubleshooting hard compared to the latter. My TPI is throwing a bunch of timing into the mix and causing pings when hot, but doesn't report a problem, mystery problems. I am putting a normal HEI back in my car, but finding no room for the vacuum advance for adjustment. My injectors are so clogged I have to run 49 PSI of fuel pressure to make it idle bad, lol... I have new injectors for it, but haven't installed them. My car is down to 12 MPG.
03-30-2009, 08:09 AM
#46
Safety Car
Sometime back I saw a thread on a guy that took a carb and mounted on top of a TPI plenum .... was a 3rd gen f-body board I believe. Not sure if it was photochopped or what but was funny to look at. whether it ran I do not know, I believe he got it off ebay, but hey yout the best of both worlds like that, long runners and a carb without electronic hassles hahaha
03-30-2009, 10:59 AM
#47
Team Owner
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Sometime back I saw a thread on a guy that took a carb and mounted on top of a TPI plenum .... was a 3rd gen f-body board I believe. Not sure if it was photochopped or what but was funny to look at. whether it ran I do not know, I believe he got it off ebay, but hey yout the best of both worlds like that, long runners and a carb without electronic hassles hahaha
05-22-2009, 03:43 AM
#50
Heel & Toe
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Well, nothing wrong with EFI and nothing wrong a carb either. Folks go ballistic if you want to put a carb on something. They are easy and they are cheap (all things considered). Yes, you might spend a few bucks getting there but when its done, ez pz.
So back to the original issue, you will flow more with a new intake and carbs. The nature of TPI is it wasn't meant to breathe at high rpm. It was built for low end grunt. Can you get EFI that will breathe at higher RPM? sure but get out the check book and learn how to program. For most of us, carbs are in fact easier and ultimately cheaper as we can do it ourselves. Having said that, EFI is efficient, takes no warm up, has good reliability (when newer) and makes good power. Dont pick on a guy if he likes carbs. Especially since they are better looking (the carbs I mean).
So back to the original issue, you will flow more with a new intake and carbs. The nature of TPI is it wasn't meant to breathe at high rpm. It was built for low end grunt. Can you get EFI that will breathe at higher RPM? sure but get out the check book and learn how to program. For most of us, carbs are in fact easier and ultimately cheaper as we can do it ourselves. Having said that, EFI is efficient, takes no warm up, has good reliability (when newer) and makes good power. Dont pick on a guy if he likes carbs. Especially since they are better looking (the carbs I mean).
05-22-2009, 07:55 AM
#51
I bought my car with the intent of putting a carbureted motor in it. I like the look and the suspension of the C4 much better than the C3. I have built and owned many early muscle cars and I have wanted to build a carbureted C4 for a long time but emissions in the big city always held me back. I moved out of the big city and now its “go time “.
Last edited by project C4; 05-22-2009 at 03:21 PM.
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sahhas (08-15-2021)
05-22-2009, 08:19 AM
#52
If you're going to go backwards in technology, why stop at a carburetor? Why not just go all the way back to a horse and buggy?
Sure, if you go through all the hood hacking hassle of putting on a good intake and carburetor, you will pick up horsepower, but it will be at the expense of low speed torque which is one of the things that makes a C4 fun to drive.
I've messed with carburetors for over 40 years, and quite proficient with them if I might say so myself, but I wouldn't rip the L98 TPI off my Vette for all the corn in Iowa.
All that said, it's your car and you have the right to do with it as you please.
My $0.02,
Doc
Sure, if you go through all the hood hacking hassle of putting on a good intake and carburetor, you will pick up horsepower, but it will be at the expense of low speed torque which is one of the things that makes a C4 fun to drive.
I've messed with carburetors for over 40 years, and quite proficient with them if I might say so myself, but I wouldn't rip the L98 TPI off my Vette for all the corn in Iowa.
All that said, it's your car and you have the right to do with it as you please.
My $0.02,
Doc
05-22-2009, 08:30 AM
#53
no hood hacking...Victor JR with the right air cleaner base fits under the stock hood.
05-22-2009, 09:46 AM
#54
Burning Brakes
Going from carbs to fuel injection takes some study. Excellent book recommedation. I respectfully submit some 6 to 8 circuit carbs are not simple at all. They may operate on simple physics (pressure differential) however after you add circuits for air conditioning, secondary throttle plates, acceleration, transmission functions, timing, etc etc. Not so simple. If you can fix carbs, you can fix fuel injection. I grew up helping my Dad at his automotive garage and saw the range from 2 barrel carbs from 1950 to the 70's in trying to make them meet emissions standards. After you read a couple chapters in various books, you'll be on the internet helping people solve various problems.
Trust me. Spend a few hours reading a few chapters per night, and you'll be a expert in two fields.
Enjoy your car.
dlmeyers
Trust me. Spend a few hours reading a few chapters per night, and you'll be a expert in two fields.
Enjoy your car.
dlmeyers
Last edited by dlmeyers; 05-22-2009 at 09:48 AM. Reason: spelling
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sahhas (08-15-2021)
05-22-2009, 11:49 AM
#55
There are many agruments for FI and for carb, but don't make the the choice based on not wanting to learn FI.
05-22-2009, 01:14 PM
#56
Safety Car
Just curious if you have no smog laws that dictate what you can/can't have on your cars and yet complain TPI cant run at high RPM why not just buy a single plane EFI manifold/miniram and so on? Carb's suck in my opinion hell I'de take CFI over a carb any day.
whats so hard to understand about and maintain fuel injection? The ecm diagnoses most any problem associated with it.
ditch the TPI, buy a single plane efi manifold, buy an elbow and mount your throttle body to it. That should get you the higher RPM's and the lowend torque of port injection. Probably cost you not much more then using a dinosaur carb.
whats so hard to understand about and maintain fuel injection? The ecm diagnoses most any problem associated with it.
ditch the TPI, buy a single plane efi manifold, buy an elbow and mount your throttle body to it. That should get you the higher RPM's and the lowend torque of port injection. Probably cost you not much more then using a dinosaur carb.
05-22-2009, 03:46 PM
#57
Yes, carburetors are easily understood with a little reading. Once you understand the basic subsystems of a carburetor, you can dissect and figure out ANY carburetor.
05-23-2009, 08:37 AM
#58
For me carbs are a mystery.....computers on the other hand I feel at home....laptop,cable,software... easy....plus if you want you can have different tunes in your chip and switch at will.
01-27-2012, 11:19 PM
#59
Instructor
hello, just wondering if you are still willing to talk about swapping to a carb from tpi, I am having trouble with tpi fuel delivery and am thinking about a swap to carb.... thanks
I swapped out my EFI setup for a Holley 750 & Performer intake, and the RPMs pick up a lot better, especially 3k-5500, but because it's not an RPM intake it falls off after 5800. Don't know what your gears are, but I have 700-R4 w/3.07s and torque is plentiful all over the powerband. I'm considering a port match & portwork on the intake this year.
The main difference between the EFI and carb is drivability - it starts rough until it warms up, may be in part for the cam, but I know most carbs have trouble in the cold. I lost about 6MPG on average, down to 14 in city and 17-18 on highway. It really depends on how many RPMs you're hitting, I cruise around at over 2500 in the city so that may be why it's so low for me. :P
If you don't like EFI, and you like tinkering with carbs, I'd go for it if you're sure that's what you want. I haven't had any problems since the swap last year, and parts for the whole setup were ~$500. It's a lot cheaper to maintain a carb than all those damn sensors with the fuel injection..
The main difference between the EFI and carb is drivability - it starts rough until it warms up, may be in part for the cam, but I know most carbs have trouble in the cold. I lost about 6MPG on average, down to 14 in city and 17-18 on highway. It really depends on how many RPMs you're hitting, I cruise around at over 2500 in the city so that may be why it's so low for me. :P
If you don't like EFI, and you like tinkering with carbs, I'd go for it if you're sure that's what you want. I haven't had any problems since the swap last year, and parts for the whole setup were ~$500. It's a lot cheaper to maintain a carb than all those damn sensors with the fuel injection..
01-27-2012, 11:35 PM
#60
Have a look ;
every aspect of carb swapping has been covered over last 10 years.
FWIW
http://forums.corvetteforum.com/foru...s-or-more.html
Not supposed to bring back up any threads that has been dead for more than 45 days;
this one is 2 1/2 years old
Last edited by vetteoz; 01-27-2012 at 11:38 PM.