CarburetorsCarb discussion and questions. Upgrading your Third Gen's carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.
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With the below completed, what should one expect as far as power is concerned?
Quote:
Originally Posted by sofakingdom
No, no one. Ever.
Seriously...
The choke points in that setup are, in the order they should be fixed:
1. Exhaust
2. Cam
3. Air cleaner
4. Electric fan
5. Gears
6. Heads
7. Converter (if it's an auto)
Notice that at NO POINT did I mention the carb, intake, or ignition system; hacking off any emissions eqpt; aftermarket "chips"; add-on ignition boxes; or other typical wastes of money. The reason those are wastes of money, is that THEY ARE NOT THE THINGS LIMITING THE CAR'S PERFORMANCE. Note also that I said "car", not "engine"; as not all of the things that make those slow, are under the hood.
1. Exhaust - needs to be replaced, as an entire unit. Every piece from the heads to the back bumper. The replacement MUST NOT be designed to fit LG4; because if it is, it will PRESERVE the LG4 exhaust bottleneck, namely, the itty bitty Y-pipe. Get one of the quality brands of headers SPECIFICALLY for one of these cars, BUT NOT for the LG4; get the ones for a TPI 350. Get a high-flow cat such as a Catco from Summit, and your choice of cat-back. All of this for something like 89 TPI 350 without G92 (single-cat setup). This will retain emissions legality (except for the EFE valve).
2. Look at cams in the 210 - 215 degree @ .050" range on the intake, with a larger exhaust lobe. Comp's XE256 and XE262 are known to work well. Crane has cams of somewhat similar specs that also give good results; I think it's the Energizer 272 but I could be wrong. Lunati's new Voodoo series is the right design for this, and may have something in the right duration range for it. Whatever cam you pick, avoid choosing it based on "sound"; any cam that "sounds" "good" will probably be too much for the rest of the engine and car. Replace the valve springs and their hardware, and the timing set, along with the cam. DO NOT try to use a modern cam under stock springs; you'll probably break something.
3. Get a dual-snorkel one from L69. This will give several HP over a typical open element, since it will give the motor cold (dense) air instead of hot, thin underhood air.
4. If your car has a clutch fan, it uses a good solid 12 HP just to run the fan. An electric fan will give you back those HP. Watch the classifieds on this site for a used fan setup.
5. Those cars were always the "sacrificial lambs" to CAFE in the V8 F-body product lineup. At the time they were new, the people who bought them were looking for the "image", not the "substance", of performance. Since anybody that was buying a new car and was seriously interested in performance avoided those like the plague, I guess GM figured they could nut them as much as they wanted to get their fuel mileage up, and nobody that bought them would care (might even like them better in fact, if they were cheaper to drive; no matter how slow). So they always got crappy gears. The best they ever got, standard, was 3.23; and most years they got 2.73 or the like. 3.42 or 3.73 makes an AMAZING difference to a 2.73 car. If yours already has 3.23s, it's not quite so urgent; but once you get the motor to breathe, it will benefit from 3.73s. In stock condition though, 3.73s will force the engine RPM so quickly up into a range where the motor has no power, that it won't really be any faster than stock; even though it will feel like it has this huge launch off the line.
6. The heads themselves are fine, entirely adequate for 305; except that they can use some porting, and larger intake valves. There is a great deal of HP available here.
7. This is like gears. The stock converter pins the motor to a very low RPM range, especially from a stop. Once you get it to where the motor has some higher-RPM power, letting it rev up when you punch it will give it a much harder "leave".
I cannot emphasize enough, RESIST THE TEMPTATION to un-bolt and re-bolt big shiny things that sit up there where everybody can see them, on top of the motor. There's an old saying you'll hear at the race track, from the people who WIN: "Chrome don't bring the money home". People who spend their limited cash on "dress-up" are choosing the path to a slow expensive car that loses races.
The parts that produce performance are INVISIBLE. Don't let that discourage you from doing the right thing. Spending your money on things you can "see", will produce little or no results; except maybe, the car will be lighter, because the driver's wallet will be thinner.
Which reminds me of another whole set of things you can do to make the CAR faster; and that is, lose weight. I don't advise hacking stuff off; few things make me puke as bad as all the people who hack off their AC, for example. But, any time you replace something, make an effort to get something lighter in its place. For example, a "mini-starter", a plastic/aluminum radiator instead of copper/brass, an aluminum drive shaft, lighter wheels, lighter flywheel if it's a 5-speed, aluminum bumper support to replace the steel one, the 82-83 "composite" hood, etc. etc. etc. You can shave an easy hundred pounds off of it that way, maybe more.
"San Leandro, CA" - I assume you have emissions testing and inspection. If that's the case, the only CA emissions legal headers for carb'd cars are the Edelbrock TES. The L69 headers are much better than the LG4 type, but if you have an LG4, you need an L69 EFE valve and L69 cat & cat-back to get the most out of it. However, an alert inspector may fail you for not having the headers and cat for your particular car.
"San Leandro, CA" - I assume you have emissions testing and inspection. If that's the case, the only CA emissions legal headers for carb'd cars are the Edelbrock TES. The L69 headers are much better than the LG4 type, but if you have an LG4, you need an L69 EFE valve and L69 cat & cat-back to get the most out of it. However, an alert inspector may fail you for not having the headers and cat for your particular car.
Good call (I'm in CA and emissions are a pain here).
Question; are you saying that the L69 version of the TES headers are better than the LG4 version of same header or that the stock L69 manifolds are better than the LG4s?
compression beyond 8.6-1 REQUIRES better gas than 87 octane my fresh LB9 with 9.6-1 compression will only run on 92 or better gas.if you can afford avgas it is 100 octane you will notice avgas has NO ethanol .as ethanol destroys aluminum it should be avoided at ALL costs
do NOT waste money for a haynes or a chilton manual they are SOOOO vague and downright dangerous to try to use.i bought a factory service manual online from helm.com and answered ALL my questions DEFINITIVELY once and for all really the quality was well worth the $100 bucks
any 305 chevy thats healthy, that has 9.6-1 compression flat top pistons and as much cam lift and duration as possible and TPI induction maybe the 58cc heads and headers will make, say 250 hp and 320 lbs. ft. torque .and thats BEFORE spray if you balance it you can spin it all day to 6000 rpm safely.get my point?13sec time slips are YOUR reality dig?
compression beyond 8.6-1 REQUIRES better gas than 87 octane my fresh LB9 with 9.6-1 compression will only run on 92 or better gas.if you can afford avgas it is 100 octane you will notice avgas has NO ethanol .as ethanol destroys aluminum it should be avoided at ALL costs
Besides some very technical reasons, that would take a small book to explain, you do not want to put 100 LL (Avgas) in a modern engine. It will clog your Cat and destroy your O2 sensors among other things. There's also a
bromide chemical in 100LL that when it gets in your oil will have a corrosive effect.
according to my 86 factory service manual it plugs into inline fuse#1 which in turn goes to fuseable link "j" that in turn goes to the starter solenoid thru fuseable link"b" or in simpler terms ,,,a inline fuse holder with a 4 amp fuse to the bat.+ side. since its a mercury switch it only comes on when you open the hood....
compression beyond 8.6-1 REQUIRES better gas than 87 octane my fresh LB9 with 9.6-1 compression will only run on 92 or better gas.if you can afford avgas it is 100 octane you will notice avgas has NO ethanol .as ethanol destroys aluminum it should be avoided at ALL costs
Really, the l03 in my caprice runs just fine on 87, gm states that it has a 9.5:1 cr.
well i agree with you five7kid. because that plug come from the sylinoid from the cowl induction but what does that plug into. and second how hard is it to swap out carbs wanting to go to an edlebrock but mine has 3 plugs that plugs into the factory carb. the edlebrock doesn't so how do i fix or get around this problem.
Did you READ this thread? Particularly post #3 that specifically DOESN'T mention swapping the carb?
__________________ "A man who voluntarily drives a car like that and still manages to maintain such impervious confidence that it will faithfully start the next time he turns that key is an encouragement for us all to take greater risks in life."
well i agree with you five7kid. because that plug come from the sylinoid from the cowl induction but what does that plug into. and second how hard is it to swap out carbs wanting to go to an edlebrock but mine has 3 plugs that plugs into the factory carb. the edlebrock doesn't so how do i fix or get around this problem.
My experiences with Edelbrock carbs isn't vast but I've owned one and I know others who have too. If you are going to swap your carb out stay away from the Edelbrock. Its a piece of ****.
Just wondering if true dual exhaust was an option to put on an 85 with the LG4 to remove airflow restrictions, or if the best bet is to just cut off the Y pipe entirely, since that seems to be the major bottleneck in the system.
Quote:
Originally Posted by five7kid
Could you explain why you posted here?
BTW, you aren't exempt.
Yes, I am. My car is no longer required to take emissions tests.
Just wondering if true dual exhaust was an option to put on an 85 with the LG4 to remove airflow restrictions, or if the best bet is to just cut off the Y pipe entirely, since that seems to be the major bottleneck in the system.
Yes, I am. My car is no longer required to take emissions tests.
Just wondering if true dual exhaust was an option to put on an 85 with the LG4 to remove airflow restrictions, or if the best bet is to just cut off the Y pipe entirely, since that seems to be the major bottleneck in the system.
Yes, I am. My car is no longer required to take emissions tests.
I do not believe that these cars got factory dual exhaust until the N10 dual cat option was available. At least not "true dual" exhaust. As for your car no longer being required to take emissions tests, that may be true. However no vehicle produced after 1973 is ever exempt from emissions regulation. You no longer have to pass emissions testing but you are not legally allowed to remove emissions control devices that the car was originally equipped with. If you even so much as throw away the charcoal canister then your car can be failed during visual inspection. Now, many emissions/inspection facilities and their employees do not know that much about emissions laws or specific vehicle models. They may or may not catch the lack of some emissions equipment like a smog pump or charcoal canister. If they do they aren't supposed to pass your vehicle.
Just fair warning. You aren't except from Federal emissions laws, just emissions testing.
The following vehicles are exempt from vehicle emissions tests:
...
Vehicles of model year 1995 or before that were in compliance with the Illinois Vehicle Emissions Inspection Law on February 1, 2007;
...
...I'm just saying...
Since the car passed three years ago, it never needs to pass again. Therefore no testing, no inspection, nada. It could be blowing pure hydrocarbons out of the tailpipe worn-out cat and they would never know.
Although, that would mean the cylinders weren't firing, and that's another problem entirely.