1978 LS3 Swap Completed.
Thread Starter
Melting Slicks
Joined: Jun 2011
Posts: 3,116
Likes: 598
mine is a .63 6th with a 3.08 diff. Which most people don’t like.
most like a 2-3 sec acceleration rush / spin tires mine is setup for road course driving and as little shifting to slow me down
optimized max speed on straightaways
Last edited by cagotzmann; Jul 7, 2021 at 10:55 AM.
Safety Car
Joined: May 2004
Posts: 4,363
Likes: 1,587
From: los altos hills california
With my carbureted motor I had to tune the advance curve from the settings that came with my controller. Guessing your motor comes with the knock sensors integrated into the ECM, mine didn't. Did you have to do anything to make your motor happy with the 91 gas in our state? Or were you plug and play out of the box?
Myself I backed off a bit from on the advance curve. There was a lot of discussion over on the LS carbureted forum at one time on what to set that too. I'm sure I sacrificed some performance.
Also, as your car is a 78, you have to meet smog in CA. Unless I missed it I didn't see any mention.
Myself I backed off a bit from on the advance curve. There was a lot of discussion over on the LS carbureted forum at one time on what to set that too. I'm sure I sacrificed some performance.
Also, as your car is a 78, you have to meet smog in CA. Unless I missed it I didn't see any mention.
Last edited by ignatz; Jul 7, 2021 at 11:47 AM.
Safety Car
Joined: May 2004
Posts: 4,363
Likes: 1,587
From: los altos hills california
It sure was. I decided to first crank with the ignition off. Took forever to see any pressure. Now it's instantaneous when I turn the key. And the oil pressure is right there too. I am baffled as to how well that works given the really long oil pickup tube.
Thread Starter
Melting Slicks
Joined: Jun 2011
Posts: 3,116
Likes: 598
Similar to what this guy did.
Thread Starter
Melting Slicks
Joined: Jun 2011
Posts: 3,116
Likes: 598
With my carbureted motor I had to tune the advance curve from the settings that came with my controller. Guessing your motor comes with the knock sensors integrated into the ECM, mine didn't. Did you have to do anything to make your motor happy with the 91 gas in our state? Or were you plug and play out of the box?
Myself I backed off a bit from on the advance curve. There was a lot of discussion over on the LS carbureted forum at one time on what to set that too. I'm sure I sacrificed some performance.
Also, as your car is a 78, you have to meet smog in CA. Unless I missed it I didn't see any mention.
Myself I backed off a bit from on the advance curve. There was a lot of discussion over on the LS carbureted forum at one time on what to set that too. I'm sure I sacrificed some performance.
Also, as your car is a 78, you have to meet smog in CA. Unless I missed it I didn't see any mention.
Safety Car
Joined: May 2004
Posts: 4,363
Likes: 1,587
From: los altos hills california
I did prime my motor with an Accusump, so I wasn't too worried about it being dry after sitting around for a year.
thanks
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7th Gear
Joined: Apr 2020
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From: Minnesota
Melting Slicks
Joined: Sep 2010
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Yeah I'm 150 miles west of the twin cities. The other thing we have run into when we have done the Power Tour is the local gas stations on the route run out of premium and you stuck with 87-89 octane gas. Never really had a problem. If the 91 octane tune costs me 10 hp I'm good with that.
Racer
Joined: Mar 2021
Posts: 278
Likes: 43
From: Kansas
you will need a 6 speed to get the higher mpg
mine is a .63 6th with a 3.08 diff. Which most people don’t like.
most like a 2-3 sec acceleration rush / spin tires mine is setup for road course driving and as little shifting to slow me down
optimized max speed on straightaways
mine is a .63 6th with a 3.08 diff. Which most people don’t like.
most like a 2-3 sec acceleration rush / spin tires mine is setup for road course driving and as little shifting to slow me down
optimized max speed on straightaways
3.55 Rear here and starting with a 2004r Trans so mine would be a .67 OD.
If I can get 23-25 mpg on cruise I'd be happy
Race Director
Joined: Mar 2017
Posts: 11,947
Likes: 4,506
From: Virginia
@cagotzmann, thanks for posting this!
It looks like you kept the stock heater/AC box to mount the ECU, vs deleting AC or using a vintage air setup. Is that correct, and did it cause any clearance issues?
It looks like you kept the stock heater/AC box to mount the ECU, vs deleting AC or using a vintage air setup. Is that correct, and did it cause any clearance issues?
Thread Starter
Melting Slicks
Joined: Jun 2011
Posts: 3,116
Likes: 598
@cagotzmann, thanks for posting this!
It looks like you kept the stock heater/AC box to mount the ECU, vs deleting AC or using a vintage air setup. Is that correct, and did it cause any clearance issues?
It looks like you kept the stock heater/AC box to mount the ECU, vs deleting AC or using a vintage air setup. Is that correct, and did it cause any clearance issues?
clearance from the Control Arms. LS3 in my 78 issues was more with the accessory drive setup. Comes with 3 options and is based on dampner depth. I have the corvette / cadilac spacing which pushes the accessory drive items to
the side, which limits options. I used a small PS pulley to clear the control arm. I worked due to me using SPC Upper arms. This also didn't require the heater hose locations to be modified as most.
Race Director
Joined: Mar 2017
Posts: 11,947
Likes: 4,506
From: Virginia
The ECU is mounted using the factory hood open / close sensor and the Heater blower relay mounts. Sits above the Heater box. I have not installed a AC pump yet, due to finding a braket that will factory mount to the LS3 and still provide
clearance from the Control Arms. LS3 in my 78 issues was more with the accessory drive setup. Comes with 3 options and is based on dampner depth. I have the corvette / cadilac spacing which pushes the accessory drive items to
the side, which limits options. I used a small PS pulley to clear the control arm. I worked due to me using SPC Upper arms. This also didn't require the heater hose locations to be modified as most.
clearance from the Control Arms. LS3 in my 78 issues was more with the accessory drive setup. Comes with 3 options and is based on dampner depth. I have the corvette / cadilac spacing which pushes the accessory drive items to
the side, which limits options. I used a small PS pulley to clear the control arm. I worked due to me using SPC Upper arms. This also didn't require the heater hose locations to be modified as most.
I have SPC arms in my 80. I'll do the same for my wife's 79 (which is, of course, is likely to be the first of the two cars to get an LS swap...). I may go with an electric power steering pump. We'll see.
Thread Starter
Melting Slicks
Joined: Jun 2011
Posts: 3,116
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Most factory pumps are ~ 2.0+ GPH for corvette factory PS units. Because of the hose movement side to side (factory) to many leak problems during track days. Worked great with the LS Swap.
Thread Starter
Melting Slicks
Joined: Jun 2011
Posts: 3,116
Likes: 598
Advanced
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