time for a rebuild
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Joined: May 2009
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From: Houma, LA
Car: 1990 camaro rs
Engine: 305 tbi
Transmission: 700R4
Axle/Gears: 2.73
time for a rebuild
Ok guys I'm going to be rebuilding the LO3, and in all honesty it doesn't need it, but its getting tired and i want to pour new life into it. Don't tell me to swap engines or anything of the sort. This engine is in great shape to be rebuilding. I want to know has anyone else rebuild it and what they used. I would like to, at the least, switch the intake and throw on a carb. But not sure what to use or what else i should change. Throw me some recommendations...
thanks tim
thanks tim
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From: Moneta, VA
Car: 88 GTA
Engine: 305 TPI
Transmission: WC T5
Axle/Gears: BW 9-bolt 3.27 posi
Re: time for a rebuild
I know that carbs are a lot more familiar territory than EFI for a lot of people... but EFI is a lot more reliable and efficient.
Thread Starter
Member
Joined: May 2009
Posts: 327
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From: Houma, LA
Car: 1990 camaro rs
Engine: 305 tbi
Transmission: 700R4
Axle/Gears: 2.73
Re: time for a rebuild
mabye but efi is too annoying to work with I'd much rather run a carb setup and if no-one is going to help can a mod move this to the carb section thanks.
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Joined: Jun 2006
Posts: 2,199
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From: West-Central
Car: 91 Trans am
Engine: built 360 TBI
Transmission: built 700r4
Axle/Gears: 10bolt/3.23
Thread Starter
Member
Joined: May 2009
Posts: 327
Likes: 0
From: Houma, LA
Car: 1990 camaro rs
Engine: 305 tbi
Transmission: 700R4
Axle/Gears: 2.73
Re: time for a rebuild
No its still on there I just don't like the fact that I need a computer to tune it and I'm dont want to have to go get stuff to tune it,ect. I'd rather just set it up like that
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Joined: Jun 2006
Posts: 2,199
Likes: 1
From: West-Central
Car: 91 Trans am
Engine: built 360 TBI
Transmission: built 700r4
Axle/Gears: 10bolt/3.23
Re: time for a rebuild
So you whant to hack up your perfectly running LO3, just keep in mind that even a carbed engine will require a computer, WB and lots of datalogging to be set up and tuned properly.
Besides calculating and controling the fueling, the ECM does control spark advance, evap canister, torque converter lock up, egr, speed limiter
, ...
With what the carb conversion is going to cost, you can upgrade your whole TBI sistem to handle some nice performance, including EBL flash wich makes tuning a real vacation.
This tread will be helpful to tune an old carb https://www.thirdgen.org/forums/carb...ng-sticky.html
Besides calculating and controling the fueling, the ECM does control spark advance, evap canister, torque converter lock up, egr, speed limiter
, ...With what the carb conversion is going to cost, you can upgrade your whole TBI sistem to handle some nice performance, including EBL flash wich makes tuning a real vacation.
This tread will be helpful to tune an old carb https://www.thirdgen.org/forums/carb...ng-sticky.html
Last edited by thomas1976; Apr 17, 2010 at 05:37 PM. Reason: add link, ecm
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Thread Starter
Member
Joined: May 2009
Posts: 327
Likes: 0
From: Houma, LA
Car: 1990 camaro rs
Engine: 305 tbi
Transmission: 700R4
Axle/Gears: 2.73
Re: time for a rebuild
I'd be fine with still running a tbi system just not sure on the parts I should buy, I've read through the stickies and im still not sure what I should be doing... still need help want this done by summers end.
thanks tim
thanks tim
Member
Joined: Sep 2007
Posts: 449
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From: RHODE ISLAND
Car: 1988 iroc-z
Engine: 350 Vortec TPI
Transmission: 700r4
Axle/Gears: 3.73 4th gen Torsen 10bolt
Re: time for a rebuild
just keep in mind that even a carbed engine will require a computer, WB and lots of datalogging to be set up and tuned properly.
Besides calculating and controling the fueling, the computer does control spark advance, evap canister, torque converter lock up, egr, speed limiter
Besides calculating and controling the fueling, the computer does control spark advance, evap canister, torque converter lock up, egr, speed limiter
fuel metering is done with jets and rods
spark advance will be handled by a vac. advance hei distributor.
evap canister goes in the trash
egr goes in the trash also
tcc can be handled by a 85 dollar kit.
computer can be sold on ebay (or go in the trash for personal gratification)
why would you want a speed limiter......................?
the lo3 is reliable but by no means fun to drive and if he dosent want to get into prom burning then go carbed
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Joined: Nov 2008
Posts: 1,545
Likes: 10
From: South Carolina
Car: 85 2M6, 87 'Bird 88 'burb
Engine: LX9, LG4, L05
Transmission: F23, 700r4, 700R4
Axle/Gears: 3.63, 2.73, 4.10
Thread Starter
Member
Joined: May 2009
Posts: 327
Likes: 0
From: Houma, LA
Car: 1990 camaro rs
Engine: 305 tbi
Transmission: 700R4
Axle/Gears: 2.73
Re: time for a rebuild
fuel metering is done with jets and rods
spark advance will be handled by a vac. advance hei distributor.
evap canister goes in the trash
egr goes in the trash also
tcc can be handled by a 85 dollar kit.
computer can be sold on ebay (or go in the trash for personal gratification)
why would you want a speed limiter......................?
the lo3 is reliable but by no means fun to drive and if he dosent want to get into prom burning then go carbed
spark advance will be handled by a vac. advance hei distributor.
evap canister goes in the trash
egr goes in the trash also
tcc can be handled by a 85 dollar kit.
computer can be sold on ebay (or go in the trash for personal gratification)
why would you want a speed limiter......................?
the lo3 is reliable but by no means fun to drive and if he dosent want to get into prom burning then go carbed
Supreme Member
Joined: Nov 2008
Posts: 1,545
Likes: 10
From: South Carolina
Car: 85 2M6, 87 'Bird 88 'burb
Engine: LX9, LG4, L05
Transmission: F23, 700r4, 700R4
Axle/Gears: 3.63, 2.73, 4.10
Re: time for a rebuild
Why not just leave the TB on and then you won't have to worry about emissions every year? my TBI 305 was about as reliable as it gets, and if you not going to put any performance goods into it, then you don't really have a whole lot of tuning to do.
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Joined: Jun 2006
Posts: 2,199
Likes: 1
From: West-Central
Car: 91 Trans am
Engine: built 360 TBI
Transmission: built 700r4
Axle/Gears: 10bolt/3.23
Re: time for a rebuild
fuel metering is done with jets and rods
spark advance will be handled by a vac. advance hei distributor.
evap canister goes in the trash
egr goes in the trash also
tcc can be handled by a 85 dollar kit.
computer can be sold on ebay (or go in the trash for personal gratification)
why would you want a speed limiter......................?
spark advance will be handled by a vac. advance hei distributor.
evap canister goes in the trash
egr goes in the trash also
tcc can be handled by a 85 dollar kit.
computer can be sold on ebay (or go in the trash for personal gratification)
why would you want a speed limiter......................?
I just mentioned the speed limitter because its one of the things that takes around 10 seconds to enable or set if you use EBL.
If you dont want to get into prom burning, you upgrade to EBL flash and go show off making impressive power without wasting lots of $$$ by evaporating fuel. Got to burn the fuel efficiently to make power.
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Joined: Sep 2007
Posts: 449
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From: RHODE ISLAND
Car: 1988 iroc-z
Engine: 350 Vortec TPI
Transmission: 700r4
Axle/Gears: 3.73 4th gen Torsen 10bolt
Re: time for a rebuild
i was under the impression he would be going with a decent cam,and headers, etc.
IT WAS BY NO MEANS A WAY TO MAKE POWER.
he suggested the carb.
that car with a cam,intake,headers and carb would make decent power.recurve the dist. and pick the right carb and it will run pretty good right out of the box.
put that stuff on a tbi and you would be lucky it ran. it can be done,it will need a tune.not everyone can tune.
with a carb you said he still needs a computer ................. i simply explained that he dident.
IT WAS BY NO MEANS A WAY TO MAKE POWER.
he suggested the carb.
that car with a cam,intake,headers and carb would make decent power.recurve the dist. and pick the right carb and it will run pretty good right out of the box.
put that stuff on a tbi and you would be lucky it ran. it can be done,it will need a tune.not everyone can tune.
with a carb you said he still needs a computer ................. i simply explained that he dident.
Last edited by regal301; Apr 16, 2010 at 05:53 PM.
Member
Joined: Sep 2007
Posts: 449
Likes: 0
From: RHODE ISLAND
Car: 1988 iroc-z
Engine: 350 Vortec TPI
Transmission: 700r4
Axle/Gears: 3.73 4th gen Torsen 10bolt
Re: time for a rebuild
so i take it you have never driven a PROPERLY SETUP AND TUNED 4BBL CAR(qjet) . pop open the secondaries and it feels like a 75 shot and the sound is something else to
and you can ride the primarys all day at 20+mpg
anyways
Last edited by regal301; Apr 16, 2010 at 06:13 PM.
Supreme Member
Joined: Jun 2006
Posts: 2,199
Likes: 1
From: West-Central
Car: 91 Trans am
Engine: built 360 TBI
Transmission: built 700r4
Axle/Gears: 10bolt/3.23
Re: time for a rebuild
Fuel supply needs to be addressed with both systems.
Since he already has TBI and posted in the TBI forum, its pretty obvious that keeping EFI and using the computer will be recommended because of all the good resons mentionned.
Assuming a mild 220 rwhp 305 ci, with the same circumstances the TBI with tuned EBL will have 1/4 to 1/3 better fuel economy. Thats a lot of money.
If you want, you can load 8 different tunes for different driving styles, different ambient themperatures, altitudes, circumstances, ... in the EBL flash and use the bank selector switch to go from one bin. to the other, by driving. With a light foot fuel efficiency tune you could make a Prius gelous.
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Joined: Jan 2008
Posts: 112
Likes: 0
From: Fort Worth, Texas
Car: 1991 RS Vert
Engine: LO3, 305, TBI
Transmission: 700R4
Axle/Gears: 3.42
Re: time for a rebuild
I'd second the EBL Flash. It's a quick install (for the most part, don't be afraid) and it will give you access to all the tuning you need.
Sure, if you are going to do some major upgrades...to a 350 with a cam, headers, turbo, etc., you might need to go a different route.
On the other hand, a nice mild 305 rebuild with some tuning capabilities, stick with the EBL Flash.
I've had my share of experience in the past with tuning carbs. It can be done, and done effectively, but sitting at my laptop and tuning the car is much more intuitive and fun.
Sure, if you are going to do some major upgrades...to a 350 with a cam, headers, turbo, etc., you might need to go a different route.
On the other hand, a nice mild 305 rebuild with some tuning capabilities, stick with the EBL Flash.
I've had my share of experience in the past with tuning carbs. It can be done, and done effectively, but sitting at my laptop and tuning the car is much more intuitive and fun.
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Member
Joined: May 2009
Posts: 327
Likes: 0
From: Houma, LA
Car: 1990 camaro rs
Engine: 305 tbi
Transmission: 700R4
Axle/Gears: 2.73
Re: time for a rebuild
wow,....not sure what to say with all the suggestions and everyone has there own opinions of course, but since I do have to pass emissions every two years I might just keep the whole setup exactly how it is take it out and store it where it wont get messed up, and swap in either a crate, 350tpi, or a Lt1. not sure what would be the cheapest to do...but that wasy I get 350 setup the way I want and just switch when emissions come, ( would be a PITA) might go for emissions early this year and get a swap going by winter, (another PITA)
thanks tim
thanks tim
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From: Moneta, VA
Car: 88 GTA
Engine: 305 TPI
Transmission: WC T5
Axle/Gears: BW 9-bolt 3.27 posi
Re: time for a rebuild
IMHO (Again, just my opinion) The least painful option other than to leave it as-is would be to go to TPI. You should have no problems with emissions inspections, and there is a wealth of resources out there for everything from running bone-stock to wild mods.
You'll get the most out of going to an LS1, but that is a very costly mod... and TPI is a lot easier to afford and install.
You'll get the most out of going to an LS1, but that is a very costly mod... and TPI is a lot easier to afford and install.
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Joined: Dec 2006
Posts: 469
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From: TX/FL
Car: 88 GTA/86 C20 Burb/91 325i
Engine: L98/454/M20
Transmission: 700R4/NV4500/Getrag
Axle/Gears: 3.27 9-bolt/3.73 14 Bolt/3.73 IRS
Re: time for a rebuild
Thomas, pardon me for being blunt, but you have no idea what you are talking about. I don't know what kind of fellows you've got over there in Switzerland, but someone with half a brain doesn't need anything more than a vacuum gauge, a tachometer, and a timing light to properly tune a non-computer controlled V8 with a Quadrajet carb and mechanical advance distributor.
Well you obviously don't get out very much do you. Or then again, it could just be you swiss, but I've been successfully running quadrajets on every car I've owned for as long as I've been driving.
And just how do you figure that? My factory short block 305 with a JEGS HEI distributor, Petronix mechanical advance spring kit, non-computer controlled carburetor, and a B&M manual converter lock up knocked down 29 mpg with a TH700R4. On the low end of your figure (1/4 more gas mileage with EFI), you're claiming you could get 36.25 mpg? 
And the high end of your figure... 38.57 mpg? Have you lost your mind?
A basic carb? Not something I would use to describe a Quadrajet... Have you ever personally worked with one? (A real one, not one of those computer controlled things) If you're dumping "crazy amounts of unburnt fuel into the air", you obviously don't know jack about tuning to begin with...
Perhaps if you have absolutely no mechanical ability, you leave the work on your car to be done by parts changers at the shop, and the extent of your tuning ends at entering numbers into the computer, you should stick with EFI. If you can read a vacuum gauge, work a timing light, and turn a screwdriver, you are more than capable of properly setting up a Quadrajet car with absolutely no computers, wide-band gauges, or voodoo involved. And the best thing about a quadrajet? If you want to build that engine in the future, heads, cam, intake, exhaust, what have you, it only takes a few minutes and the same basic tools to retune the engine. No new flashes, no programming, and no hinky code to have to try and figure out.
Tim, if you'd like any info on doing the carb conversion, let me know. I didn't go straight from TBI, but I did go from a computer controlled quadrajet back to pure mechanical controls. It's very simple, much easier to work on, and a heck of a lot more reliable than any 20 year old fuel injection system I've ever worked with. And just to quantify, I've got a TBI on my Suburban, and I'll be going Q-jet on that as well in the very near future.
Just my $.02. Sorry for the rant, I just can't stand people bashing carbs who don't have a clue what they're talking about.
-Levi
I do not know anybody, owning a sports car with a carburator, that does not use a computer and a WB wenn tuning it, to make the best power and to make sure they dont ruin the engine by doing so.
Assuming a mild 220 rwhp 305 ci, with the same circumstances the TBI with tuned EBL will have 1/4 to 1/3 better fuel economy. Thats a lot of money.
And the high end of your figure... 38.57 mpg? Have you lost your mind?
Are you seriously suggesting someone should slap such a basic carb on a LO3? Thats like turning a not soo fun car into a junk mobile that evaporates crazy amounts of unburnt fuel into the air. Hope you realize he won't make any more power with that carb then now, either.
Perhaps if you have absolutely no mechanical ability, you leave the work on your car to be done by parts changers at the shop, and the extent of your tuning ends at entering numbers into the computer, you should stick with EFI. If you can read a vacuum gauge, work a timing light, and turn a screwdriver, you are more than capable of properly setting up a Quadrajet car with absolutely no computers, wide-band gauges, or voodoo involved. And the best thing about a quadrajet? If you want to build that engine in the future, heads, cam, intake, exhaust, what have you, it only takes a few minutes and the same basic tools to retune the engine. No new flashes, no programming, and no hinky code to have to try and figure out.
Tim, if you'd like any info on doing the carb conversion, let me know. I didn't go straight from TBI, but I did go from a computer controlled quadrajet back to pure mechanical controls. It's very simple, much easier to work on, and a heck of a lot more reliable than any 20 year old fuel injection system I've ever worked with. And just to quantify, I've got a TBI on my Suburban, and I'll be going Q-jet on that as well in the very near future.
Just my $.02. Sorry for the rant, I just can't stand people bashing carbs who don't have a clue what they're talking about.
-Levi
Supreme Member
Joined: Jun 2006
Posts: 2,199
Likes: 1
From: West-Central
Car: 91 Trans am
Engine: built 360 TBI
Transmission: built 700r4
Axle/Gears: 10bolt/3.23
Re: time for a rebuild
Thomas, pardon me for being blunt, but you have no idea what you are talking about. I don't know what kind of fellows you've got over there in Switzerland, but someone with half a brain doesn't need anything more than a vacuum gauge, a tachometer, and a timing light to properly tune a non-computer controlled V8 with a Quadrajet carb and mechanical advance distributor.
Well you obviously don't get out very much do you. Or then again, it could just be you swiss, but I've been successfully running quadrajets on every car I've owned for as long as I've been driving.
And just how do you figure that? My factory short block 305 with a JEGS HEI distributor, Petronix mechanical advance spring kit, non-computer controlled carburetor, and a B&M manual converter lock up knocked down 29 mpg with a TH700R4. On the low end of your figure (1/4 more gas mileage with EFI), you're claiming you could get 36.25 mpg? And the high end of your figure... 38.57 mpg? Have you lost your mind?
A basic carb? Not something I would use to describe a Quadrajet... Have you ever personally worked with one? (A real one, not one of those computer controlled things) If you're dumping "crazy amounts of unburnt fuel into the air", you obviously don't know jack about tuning to begin with...
Perhaps if you have absolutely no mechanical ability, you leave the work on your car to be done by parts changers at the shop, and the extent of your tuning ends at entering numbers into the computer, you should stick with EFI. If you can read a vacuum gauge, work a timing light, and turn a screwdriver, you are more than capable of properly setting up a Quadrajet car with absolutely no computers, wide-band gauges, or voodoo involved. And the best thing about a quadrajet? If you want to build that engine in the future, heads, cam, intake, exhaust, what have you, it only takes a few minutes and the same basic tools to retune the engine. No new flashes, no programming, and no hinky code to have to try and figure out.
Tim, if you'd like any info on doing the carb conversion, let me know. I didn't go straight from TBI, but I did go from a computer controlled quadrajet back to pure mechanical controls. It's very simple, much easier to work on, and a heck of a lot more reliable than any 20 year old fuel injection system I've ever worked with. And just to quantify, I've got a TBI on my Suburban, and I'll be going Q-jet on that as well in the very near future.
Just my $.02. Sorry for the rant, I just can't stand people bashing carbs who don't have a clue what they're talking about.
-Levi
Well you obviously don't get out very much do you. Or then again, it could just be you swiss, but I've been successfully running quadrajets on every car I've owned for as long as I've been driving.
And just how do you figure that? My factory short block 305 with a JEGS HEI distributor, Petronix mechanical advance spring kit, non-computer controlled carburetor, and a B&M manual converter lock up knocked down 29 mpg with a TH700R4. On the low end of your figure (1/4 more gas mileage with EFI), you're claiming you could get 36.25 mpg?
And the high end of your figure... 38.57 mpg? Have you lost your mind?A basic carb? Not something I would use to describe a Quadrajet... Have you ever personally worked with one? (A real one, not one of those computer controlled things) If you're dumping "crazy amounts of unburnt fuel into the air", you obviously don't know jack about tuning to begin with...
Perhaps if you have absolutely no mechanical ability, you leave the work on your car to be done by parts changers at the shop, and the extent of your tuning ends at entering numbers into the computer, you should stick with EFI. If you can read a vacuum gauge, work a timing light, and turn a screwdriver, you are more than capable of properly setting up a Quadrajet car with absolutely no computers, wide-band gauges, or voodoo involved. And the best thing about a quadrajet? If you want to build that engine in the future, heads, cam, intake, exhaust, what have you, it only takes a few minutes and the same basic tools to retune the engine. No new flashes, no programming, and no hinky code to have to try and figure out.
Tim, if you'd like any info on doing the carb conversion, let me know. I didn't go straight from TBI, but I did go from a computer controlled quadrajet back to pure mechanical controls. It's very simple, much easier to work on, and a heck of a lot more reliable than any 20 year old fuel injection system I've ever worked with. And just to quantify, I've got a TBI on my Suburban, and I'll be going Q-jet on that as well in the very near future.
Just my $.02. Sorry for the rant, I just can't stand people bashing carbs who don't have a clue what they're talking about.
-Levi
It was no big deal to make 32 mpg with the LO3, LT1cam, full exhaust, 2.73 and EBL on the highway.
If you say you can make the same power and then have the same fuel efficiency, daily driving, using a carb intead of EFI, in that case you would have interpreted correct.
You preferring the carb and slaping a carb on all of your cars, dosen't make EFI a bad invention.
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Joined: Dec 2006
Posts: 469
Likes: 1
From: TX/FL
Car: 88 GTA/86 C20 Burb/91 325i
Engine: L98/454/M20
Transmission: 700R4/NV4500/Getrag
Axle/Gears: 3.27 9-bolt/3.73 14 Bolt/3.73 IRS
Re: time for a rebuild
No it does not, and I have run EFI as well, but the fact remains that a carb is just as efficient, just as powerful, and a whole lot simpler to work on.
To claim that you can get 1/4 to 1/3 more gas mileage and more power than a well tuned quadrajet is simply ludicrous. No insulting involved, just facts.
-Levi
To claim that you can get 1/4 to 1/3 more gas mileage and more power than a well tuned quadrajet is simply ludicrous. No insulting involved, just facts.
-Levi
Supreme Member
Joined: Jun 2006
Posts: 2,199
Likes: 1
From: West-Central
Car: 91 Trans am
Engine: built 360 TBI
Transmission: built 700r4
Axle/Gears: 10bolt/3.23
Re: time for a rebuild
No it does not, and I have run EFI as well, but the fact remains that a carb is just as efficient, just as powerful, and a whole lot simpler to work on.
To claim that you can get 1/4 to 1/3 more gas mileage and more power than a well tuned quadrajet is simply ludicrous. No insulting involved, just facts.
-Levi
To claim that you can get 1/4 to 1/3 more gas mileage and more power than a well tuned quadrajet is simply ludicrous. No insulting involved, just facts.
-Levi
Member
iTrader: (16)
Joined: Dec 2006
Posts: 469
Likes: 1
From: TX/FL
Car: 88 GTA/86 C20 Burb/91 325i
Engine: L98/454/M20
Transmission: 700R4/NV4500/Getrag
Axle/Gears: 3.27 9-bolt/3.73 14 Bolt/3.73 IRS
Re: time for a rebuild
What's there to reinterpret? You were very plain in what you had to say about the efficiency benefits of EFI while bashing the Quadrajet with numerous derogatory insults. The OP was looking to alternatives to EFI, and mentioned a carb, which IMO is a good idea if he's making the move to convert anyways. Then you proceeded to bash such a logical alternative in a manner that was neither based on fact nor reasonable claims.
The simple fact is, there's no way you can pick up 25-33% more efficiency over a properly tuned quadrajet by switching to EFI. There's also no reasonable expectation of producing more power with EFI as opposed to a carburetor. To claim either is simply a falsity.
-Levi
The simple fact is, there's no way you can pick up 25-33% more efficiency over a properly tuned quadrajet by switching to EFI. There's also no reasonable expectation of producing more power with EFI as opposed to a carburetor. To claim either is simply a falsity.
-Levi
Supreme Member
Joined: Jun 2006
Posts: 2,199
Likes: 1
From: West-Central
Car: 91 Trans am
Engine: built 360 TBI
Transmission: built 700r4
Axle/Gears: 10bolt/3.23
Re: time for a rebuild
What's there to reinterpret? You were very plain in what you had to say about the efficiency benefits of EFI while bashing the Quadrajet with numerous derogatory insults. The OP was looking to alternatives to EFI, and mentioned a carb, which IMO is a good idea if he's making the move to convert anyways. Then you proceeded to bash such a logical alternative in a manner that was neither based on fact nor reasonable claims.
The simple fact is, there's no way you can pick up 25-33% more efficiency over a properly tuned quadrajet by switching to EFI. There's also no reasonable expectation of producing more power with EFI as opposed to a carburetor. To claim either is simply a falsity.
-Levi
The simple fact is, there's no way you can pick up 25-33% more efficiency over a properly tuned quadrajet by switching to EFI. There's also no reasonable expectation of producing more power with EFI as opposed to a carburetor. To claim either is simply a falsity.
-Levi
Supreme Member
Joined: May 2000
Posts: 2,963
Likes: 3
Car: 1982 Z28
Engine: LS1
Transmission: T56
Re: time for a rebuild
If electronics annoy you, then an LS1 will be down-right maddening for you.
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Joined: May 2000
Posts: 2,963
Likes: 3
Car: 1982 Z28
Engine: LS1
Transmission: T56
Re: time for a rebuild
Let's suppose you spent time on a dyno with a wideband O2 crammed into the exhaust, jetted your Q-jet and dialed in the metering rods just right, got the secondaries opening at the optimum rate.
Those adjustments would only yield a "properly tuned" carb for the ambient conditions at the time it was tuned.
As soon as the temps change, or you drive it to a significantly different elevation, or that darn Winter blended gas arrives...you're no longer "properly tuned" are you?
Saying that a carb can run an engine as efficiently as a closed-loop EFI system that accounts for varying operating conditions is what you referred to as a "falsity."
Fuel atomization downstream of a venturi is never, ever, no matter how bad you want it to be, going to be as good and as homogeneous as a direct port injector can deliver.
The reality is that the average tinkerer gets the carb tuned enough for the engine to run and stops there. "Properly tuned" is not the state of most do-it-yourself carbs.
And yes, I used to tweak Q-jets and was a big fan of the spreadbore design versus the Holley symmetrical bores. Great throttle response and efficiency from the tiny primaries, and massive response when the big secondaries open up.
I wouldn't trade back from EFI for any reason other than a massive atmospheric EMP detonation.
Thread Starter
Member
Joined: May 2009
Posts: 327
Likes: 0
From: Houma, LA
Car: 1990 camaro rs
Engine: 305 tbi
Transmission: 700R4
Axle/Gears: 2.73
Re: time for a rebuild
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Joined: Dec 2005
Posts: 1,244
Likes: 1
From: Texas City, Texas Area
Car: 89 RS, 92 Z28
Engine: 305 TBI, 350 TPI
Transmission: 700R4 Both Cars
Axle/Gears: 3.23 Posi.. 4 wheel disc both cars
Re: time for a rebuild
Not everyone is a fan of EFI...I myself have mixed feelings, and have swayed between carb, and EFI...a properly tuned carb will work just fine, and provide good throttle response, and power...economy can be good also..now as far as passing the smog test, that is another subject...EFI can be pretty damn scary...I have been working on cars for 30 plus years, and I am still intimidated by chip burning, and such...Also it is hard to get direct answers on the subject...I do know how to read plugs, and tune a carb, and yes you can use a o2 sensor for tuning, but it is not critical...Many a race car still run on carbed motors, and they have pretty good effecincy....I know they seem ancient to alot of folks, but they have been around for years...That said, I still have my TBI on my car which I have had for a good number of years...My last 3rd gen was a carbed 350 "built"...I do like my TBI, but I wish I knew more about the tuning part...I am a total beginner....To each his own guys....
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backtothe80s
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Sep 5, 2015 12:39 AM
