I put ceramic coated headers on my 1977, true dual exhaust, shift kit, 390 rear. Noticed a big difference.
1979 poor performance
Thread Starter
Heel & Toe
Joined: Jun 2009
Posts: 16
Likes: 0
1979 poor performance
I have a 1979 L82 automatic. I just had the carb rebuilt but still my Subaru Legacy without a turbo has more get up and go...I know that 79 wasnt a high power year but this car wont even chirp the tires, let alone smoke em....Any advice besides a swap
Burning Brakes
Joined: Jun 2008
Posts: 1,086
Likes: 1
From: Michigan
The least expensive and easiest thing you can do is to read the timing sticky at the top of the page and work on the timing. As mentioned above a good tune up and check up is a good idea to be sure you don't have any electrical spark or vacuum leaks. Get the timing as perfect as you can before you start messing with the carb.
The late C3's are real dogs so GM had to make them nice cruisers.
The late C3's are real dogs so GM had to make them nice cruisers.
Le Mans Master
Joined: Oct 2005
Posts: 6,247
Likes: 471
From: Glen Allen, VA
Agreed. Dialing in the timing curve will make a noticable difference. I did on my 79. Keep in mind that a stock 79 Corvette L-82 was clocked new if I remember right at 6.6 0-60 and 15 flat in the quarter. If you look up the specs, a new V6 Accord will run about those same numbers, so your Legacy may not be far off.
Racer
Joined: Mar 2002
Posts: 406
Likes: 1
From: Maroochydore QLD
Hee hee, your Subaru has more get up and go, well something is definately wrong if your 2 litre flat four torqueless tiger can out perform your 79, mine is absolutley stock but I can run a Subaru down any day, at the very least I hope your car has more torque than your subaru, even if it doesnt have off the line speed, horizontally opposed motors may be well balanced but they are never famous for their torque unless they are built specifically for it, just rotational speed.
Worse case scenario, de-tune your Subaru just so you feel better.
Cheers, Dennis.
Worse case scenario, de-tune your Subaru just so you feel better.
Cheers, Dennis.
Heel & Toe
Joined: Mar 2010
Posts: 20
Likes: 0
Its a 1979, most anything on the road today will burn that car in a race including a Ford Focus. It couldnt smoke or even chirp the tires when it left the dealer... Pull that small block out and hook it up with a fresh powerplant.
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Racer
Joined: Mar 2002
Posts: 406
Likes: 1
From: Maroochydore QLD
My stock L48 auto burns the tires in 1st any time I ask it to, it also drinks fuel at about 2 liters per second when I do but that fact remains that it is a stock L48 and burns rubber easily, it also menaces many cars on the roads, again if I ask it to, granted many ricers today can out run it from a standing start very few have the torque that gives you a woody, expecially under 6000rpm, mine does. I live at the top of a VERY steep hill, when I get a ricer trying to give me a run behind me coming up to that hill, I slow down to 40mph at the bottom of the hill and then I plant my foot, tires chirp (dropping back to 2nd) and ricer is a distant image in the mirror, yes even subarus, why? because they have no torque unless they already have their rpm above 4000 when I do it to them. Makes me smile. Only juice and milk comes in two liters.
Cheers, Dennis.
Drifting
Joined: Aug 2009
Posts: 1,635
Likes: 8
From: Enid Oklahoma
Here's my 2 liter
What color is the sky on your planet? maybe Orange?
My stock L48 auto burns the tires in 1st any time I ask it to, it also drinks fuel at about 2 liters per second when I do but that fact remains that it is a stock L48 and burns rubber easily, it also menaces many cars on the roads, again if I ask it to, granted many ricers today can out run it from a standing start very few have the torque that gives you a woody, expecially under 6000rpm, mine does. I live at the top of a VERY steep hill, when I get a ricer trying to give me a run behind me coming up to that hill, I slow down to 40mph at the bottom of the hill and then I plant my foot, tires chirp (dropping back to 2nd) and ricer is a distant image in the mirror, yes even subarus, why? because they have no torque unless they already have their rpm above 4000 when I do it to them. Makes me smile. Only juice and milk comes in two liters.
Cheers, Dennis.
My stock L48 auto burns the tires in 1st any time I ask it to, it also drinks fuel at about 2 liters per second when I do but that fact remains that it is a stock L48 and burns rubber easily, it also menaces many cars on the roads, again if I ask it to, granted many ricers today can out run it from a standing start very few have the torque that gives you a woody, expecially under 6000rpm, mine does. I live at the top of a VERY steep hill, when I get a ricer trying to give me a run behind me coming up to that hill, I slow down to 40mph at the bottom of the hill and then I plant my foot, tires chirp (dropping back to 2nd) and ricer is a distant image in the mirror, yes even subarus, why? because they have no torque unless they already have their rpm above 4000 when I do it to them. Makes me smile. Only juice and milk comes in two liters.
Cheers, Dennis.
And it will take your Vette, notice the 125 C.I. badge and the Z rated car tire on the rear.
Just funnin, but it is fast and 2053 CC's
Heel & Toe
Joined: Mar 2010
Posts: 20
Likes: 0
Aussie my sky color is bright blue!!!!!!!!!!
What color is the sky on your planet? maybe Orange?
My stock L48 auto burns the tires in 1st any time I ask it to, it also drinks fuel at about 2 liters per second when I do but that fact remains that it is a stock L48 and burns rubber easily, it also menaces many cars on the roads, again if I ask it to, granted many ricers today can out run it from a standing start very few have the torque that gives you a woody, expecially under 6000rpm, mine does. I live at the top of a VERY steep hill, when I get a ricer trying to give me a run behind me coming up to that hill, I slow down to 40mph at the bottom of the hill and then I plant my foot, tires chirp (dropping back to 2nd) and ricer is a distant image in the mirror, yes even subarus, why? because they have no torque unless they already have their rpm above 4000 when I do it to them. Makes me smile. Only juice and milk comes in two liters.
Cheers, Dennis.
My stock L48 auto burns the tires in 1st any time I ask it to, it also drinks fuel at about 2 liters per second when I do but that fact remains that it is a stock L48 and burns rubber easily, it also menaces many cars on the roads, again if I ask it to, granted many ricers today can out run it from a standing start very few have the torque that gives you a woody, expecially under 6000rpm, mine does. I live at the top of a VERY steep hill, when I get a ricer trying to give me a run behind me coming up to that hill, I slow down to 40mph at the bottom of the hill and then I plant my foot, tires chirp (dropping back to 2nd) and ricer is a distant image in the mirror, yes even subarus, why? because they have no torque unless they already have their rpm above 4000 when I do it to them. Makes me smile. Only juice and milk comes in two liters.
Cheers, Dennis.
Dennis,
I take it you dont live in the US where pretty much anything on the road will smoke a stock 79 L48 (sorry for those of you who I offend, but its just a fact.....doesnt mean that its not awesome to own a 79 Corvette, just dont expect it to perform well). Your car I have no doubt could beat some of those little cars that the US will not allow to drive on the roads here due to safety issues or burn the tires for a split second with a manual trans if you drop the clutch (good luck trying to spin the tires on a stock L48 with an auto). I have driven 78's and 79's and know that the 89 Grand Prix I had with a 6 cylinder could have smoked either one of them. However (dakotagoon) with his 81 could prolly smoke most things on the road!
Racer
Joined: Mar 2002
Posts: 406
Likes: 1
From: Maroochydore QLD
Dennis,
I take it you dont live in the US where pretty much anything on the road will smoke a stock 79 L48 (sorry for those of you who I offend, but its just a fact.....doesnt mean that its not awesome to own a 79 Corvette, just dont expect it to perform well). Your car I have no doubt could beat some of those little cars that the US will not allow to drive on the roads here due to safety issues or burn the tires for a split second with a manual trans if you drop the clutch (good luck trying to spin the tires on a stock L48 with an auto). I have driven 78's and 79's and know that the 89 Grand Prix I had with a 6 cylinder could have smoked either one of them. However (dakotagoon) with his 81 could prolly smoke most things on the road!
I take it you dont live in the US where pretty much anything on the road will smoke a stock 79 L48 (sorry for those of you who I offend, but its just a fact.....doesnt mean that its not awesome to own a 79 Corvette, just dont expect it to perform well). Your car I have no doubt could beat some of those little cars that the US will not allow to drive on the roads here due to safety issues or burn the tires for a split second with a manual trans if you drop the clutch (good luck trying to spin the tires on a stock L48 with an auto). I have driven 78's and 79's and know that the 89 Grand Prix I had with a 6 cylinder could have smoked either one of them. However (dakotagoon) with his 81 could prolly smoke most things on the road!
Heel & Toe
Joined: Mar 2010
Posts: 20
Likes: 0
Ummmmm, do you actually know where Australia is? we build small block chev engines here (GM factory) and ship them to you guys to use in your cars. We have all the same japanese/korean cars here that you do, in fact same cars from all over the world you do, just not many American cars as import duties from you guys are too high. In fact, I bet we have more cars from around the world here coz we dont give a sh*t about smog laws here so we can get away with just about anything where you guys in most states are so restricted it just isnt funny. And say what you like, if I hold my car in 1st, perform a brake burnout I can smoke the tires as long as I want, in fact I just got new tires recently and thought I would smoke my neighbours out for fun with the old ones (I dont like them and they dont like me) so I did a 20 second burnout in my driveway (foot lightly on brakes) and you couldnt see their house for the smoke. Any experience you have in 79's must have been with worn out clunkers. Cheers, Dennis.
Ok, your are right! 79's must have had power because GM now has a plant that makes motors in Australia
...... makes sense to me! Anyway dakotagoon's 81 will probably smoke most things on the road (sweet looking ride)!!!!cheers
Last edited by Orange74UL5; Mar 11, 2010 at 10:13 PM.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
I'm guessing that your carb secondaries are not opening. Happens to a lot of C3 owners who think their car is a "dog". First thing to check is whether pushing the accel pedal to the floor really actuates the secondaries. If it doesn't, adjust the throttle cable or get rid of the floor mat. If it does actuate properly, then make sure the choke is fully releasing when the engine is warm [or the secondary lock-out will keep them from opening]. Good luck with your 'sleuthing'...
Drifting
Joined: Aug 2009
Posts: 1,635
Likes: 8
From: Enid Oklahoma
I'm guessing that your carb secondaries are not opening. Happens to a lot of C3 owners who think their car is a "dog". First thing to check is whether pushing the accel pedal to the floor really actuates the secondaries. If it doesn't, adjust the throttle cable or get rid of the floor mat. If it does actuate properly, then make sure the choke is fully releasing when the engine is warm [or the secondary lock-out will keep them from opening]. Good luck with your 'sleuthing'...
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
Q-jet secondaries are NOT vacuum operated. The venturi plates open with the throttle linkage but the upper airvalve opens with airflow and is self-regulating. The airvalve may [or may not] have a vacuum operated release mechanism which allows the secondaries to function under specific operating conditions.
The throttle linkage on a Q-jet only starts to open the secondaries at the very last bit of travel. More owners than you can count have their linkage/cable mis-adjusted to the point that they will never kick in.
To the OP: Read my post again and check it out for yourself. Don't get misled by those who profess knowledge, but don't really have a full understanding of the subject.
The throttle linkage on a Q-jet only starts to open the secondaries at the very last bit of travel. More owners than you can count have their linkage/cable mis-adjusted to the point that they will never kick in.
To the OP: Read my post again and check it out for yourself. Don't get misled by those who profess knowledge, but don't really have a full understanding of the subject.
Drifting
Joined: Aug 2009
Posts: 1,635
Likes: 8
From: Enid Oklahoma
Q-jet secondaries are NOT vacuum operated. The venturi plates open with the throttle linkage but the upper airvalve opens with airflow and is self-regulating. The airvalve may [or may not] have a vacuum operated release mechanism which allows the secondaries to function under specific operating conditions.
The throttle linkage on a Q-jet only starts to open the secondaries at the very last bit of travel. More owners than you can count have their linkage/cable mis-adjusted to the point that they will never kick in.
To the OP: Read my post again and check it out for yourself. Don't get misled by those who profess knowledge, but don't really have a full understanding of the subject.
The throttle linkage on a Q-jet only starts to open the secondaries at the very last bit of travel. More owners than you can count have their linkage/cable mis-adjusted to the point that they will never kick in.
To the OP: Read my post again and check it out for yourself. Don't get misled by those who profess knowledge, but don't really have a full understanding of the subject.
Whatever, you originally gave him the impression they were totally linkage operated then gave him more info that corrected yourself. Airflow/ vacuum semantics. The fact is that a low pressure gradient is introduced to allow for them to open... that low pressure (you call it airflow) allows them to open fully. So I guess based on your last comment we should all bow to your knowledge? If so, I am humbled by your presence, and give summary lordship to you over all things mechanical and promise not to ever be in conflict with your knowledge again..(bowing and backing away)
Last edited by 81pilot; Mar 12, 2010 at 12:29 PM.