Builds LS2 L76 V8 and 6L80E Swap in 1997 40th FJ80 (1 Viewer)

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Here is a little better pic.
image-3487159457.jpg
 
one word!

Awesome.

Please report back with fuel economy and power impressions?

I had a GT35R turbocharged setup on my last Cruiser and it had good power especially at altitude. Probably only made about 350hp though as it was running about 8psi on factory tune/inj/fuel pump/91 octane. It would easily pull away from my friends supercharged 4.5 Cruiser. He wasn't too happy about that!
 
OK, so the LS2 vs LS3 thing just got me... I know crap about Chevy motors, so i Googled it... All the Corvette guys love the LS2, and extol it's virtues, but say that the LS3 is a genuine generational step up and (I quote) is THE hot motor of the future.

Oh, and it's a 6.2 liter. Damn. You are going to love this cruiser, I imagine. Your first post was quite...Casual about the swap, so how about some details?
-Want to hear about what works, what needs work
- any gauge switch outs or using OEM gauges?
-Ballpark cost for the conversion, including the LS3
-What was done to mate to the transfer case, or was that swapped.
-will you be running full or P/T 4WD?

Sorry for inundating you with ?s, but this is a cool project.

Ok, here are some of the answers requested...
The what works question is still to be determined as I drive her but for now, deceleration idle seems to be the issue I trying resolve so I can actually drive her. currently as we decelerate, she stalls out. Hopefully the guys at performance will have that all resolved by tomorrow. From what my mechanic has told me, my 2nd start button won't work anymore. I will post more on this question in the near future.

I am trying to keep her close to stock looking and have been using the stock gauges. Speedometer seemed to work ok, but the Tach was registering about half of what it should. Working on that issue now as well.

Costs... not for the faint hearted. So far, I found the LS3 Engine and 6L80e Tranny as a dropout with 43,000 miles on them and paid $6450.00 for them shipped to my mechanic (This was supposed to have been an L76 package out of a G8 GT, but I am not complaining about that err in my favor as it was a GXP). I bought an adapter kit from Marks4wd.com for $1260.00 shipped. New wire harness from Street Performance for $1060.00. Tuning package from Street Performance for another $370.00. New 3 inch exhaust piping for $375.00 Flowmaster Hushpower Pro Series Muffler for $120.00. Cam Shaft upgrade, $600.00 including Labor that that. Labor for the swap came in at $4700.00 for the Engine Swap work which also included some miscellaneous parts such as second battery set up, open air intake, and stand alone fuse management setup for the new engine and tranny. There has been a fair amount of fabrication work that has had to be done as well. I cannot say I got a steal on the labor portion of this thing, but I have been happy with the quality of work my mechanic is doing. However, after this OME Suspension upgrade... I am broke! Have to save up for a while to do the other projects on my wish list.

I am still planning on running full time 4wd on her.
 
Your stalling issue sounds like the torque converter is not unlocking.

Do you know if the installer added a circuit that tells the PCM to unlock the convertor when you hit the brakes?

This is from the LT1Swap website:

Brake Switch Signal - For automatics with lock up converter, the PCM needs signal when brake pedal is pressed. However, the signal needed is opposite how you're brake lights work. The PCM wants 12v+ constant on this wire when brake IS NOT pressed, and OPEN Circuit when the brake IS pressed. If you vehicle was equipped with a lockup trans to begin with, you probably already have the proper normally closed switch mounted by your brake light switch. If you do not, you can use a relay to perform the same thing. On most relays, there are 5 terminals, 2 of them turn the relay ON when provided ground/power. There are then a normally open leg and a normally closed leg on the relay and a supply. By feeding 12v+ on the supply leg, and hooking the Brake Switch Signal wire to the normally closed leg, you will now have the correct signal for the PCM. When the brake is pressed, 12v+ flows to brake lights, tap into this wire, and run it to the relay to turn the relay on. This will cause the normally closed leg to become open, thus turning OFF the 12v+ signal to the PCM. When you release the brake pedal, the relay will turn OFF, and then feed 12v+ to the PCM.

The tach issue can be fixed by getting a dakota digital convertor box and using it to modify the tach output from the PCM. The other option is to have your programmer use the software to output a signal that matches the 6 cylinder tach input.

Also, in regards to the second gear start - while the button no longer works, the transmission retains the ability for second gear start simply by shifting into 2nd gear.
 
Last edited:
rockrod said:
Your stalling issue sounds like the torque converter is not unlocking.

Do you know if the installer added a circuit that tells the PCM to unlock the convertor when you hit the brakes?

This is from the LT1Swap website:

Brake Switch Signal - For automatics with lock up converter, the PCM needs signal when brake pedal is pressed. However, the signal needed is opposite how you're brake lights work. The PCM wants 12v+ constant on this wire when brake IS NOT pressed, and OPEN Circuit when the brake IS pressed. If you vehicle was equipped with a lockup trans to begin with, you probably already have the proper normally closed switch mounted by your brake light switch. If you do not, you can use a relay to perform the same thing. On most relays, there are 5 terminals, 2 of them turn the relay ON when provided ground/power. There are then a normally open leg and a normally closed leg on the relay and a supply. By feeding 12v+ on the supply leg, and hooking the Brake Switch Signal wire to the normally closed leg, you will now have the correct signal for the PCM. When the brake is pressed, 12v+ flows to brake lights, tap into this wire, and run it to the relay to turn the relay on. This will cause the normally closed leg to become open, thus turning OFF the 12v+ signal to the PCM. When you release the brake pedal, the relay will turn OFF, and then feed 12v+ to the PCM.

The tach issue can be fixed by getting a dakota digital convertor box and using it to modify the tach output from the PCM. The other option is to have your programmer use the software to output a signal that matches the 6 cylinder tach input.

Also, in regards to the second gear start - while the button no longer works, the transmission retains the ability for second gear start simply by shifting into 2nd gear.

Thanks Rockrod. I sent your recommendations over to my installer and he said that he had done this. He sent my computer off to be retuned to increase the deceleration idle, I am also scheduled to have the transmission retuned to have the corvette shift points on Friday morning. He thought this would help with the hunting for gears along with these issues.
 
Got the Dakota Digital part installed and the Tach works, however the Speedometer isn't coming to life. Any advice?
 
jwdodd1 said:
Got the Dakota Digital part installed and the Tach works, however the Speedometer isn't coming to life. Any advice?

Dakota got us all squared away. Everything appears to be working now.
 
Also, in regards to the second gear start - while the button no longer works, the transmission retains the ability for second gear start simply by shifting into 2nd gear.

The transmission he has allows that?
I have never seen any automatic transmission allow you to start off in second gear just because you have the selector lever in 2nd.(except for the button allowing it on LCs) The trans will start in 1st and only allow the vehicle to go as high as 2nd gear if you have the selector on 2nd.
 
This is a awesome setup, where in NOVA are you located? I would like to check it out in person if its not a problem .:cheers:
 
The transmission he has allows that?
I have never seen any automatic transmission allow you to start off in second gear just because you have the selector lever in 2nd.(except for the button allowing it on LCs) The trans will start in 1st and only allow the vehicle to go as high as 2nd gear if you have the selector on 2nd.

Yes - putting the shifter in second will force the trans to start off in 2nd. It serves the same purpose that toyota implemented with the '95 and later trucks and reduces torque to the wheels as a poor-mans traction control. I don't think all domestic autos can do this, but it's pretty common in the GM, Ford and Mopar. It does lock the trans in second gear unless you go so fast that you hit redline and the PCM forces the upshift into 3rd. The trans will protect the engine.

I never thought to test this on my '94 before the swap. It does not have the second gear start button like the later trucks and I don't recall the owners manual calling this out either.
 
Dakota got us all squared away. Everything appears to be working now.

including the speedo?

It uses a speed sensor on the t-case so power and ground need to be provided to the sensor, and the output signal goes to the speedo. The wires are buried in the toyota harness that operates the original toyota transmission and the CDL.
 
rockrod said:
including the speedo?

It uses a speed sensor on the t-case so power and ground need to be provided to the sensor, and the output signal goes to the speedo. The wires are buried in the toyota harness that operates the original toyota transmission and the CDL.

Yep, speedo is working fine. Picked her up today and drove home fine, but when I shut her off, I heard a gurgling noise. When I opened the hood, it sounded as though the coolant was boiling. I think it may have been on the verge of overheating. Any ideas on what to check to verify?
 
rockrod said:
including the speedo?

It uses a speed sensor on the t-case so power and ground need to be provided to the sensor, and the output signal goes to the speedo. The wires are buried in the toyota harness that operates the original toyota transmission and the CDL.

Thanks for getting back to me on this though.
 
slow91fj90 said:
This is a awesome setup, where in NOVA are you located? I would like to check it out in person if its not a problem .:cheers:

Thanks, it has been fun seeing her come together. I just need to work out the little bugs now. And yes, Winchester. Let me know if you are ever this way.
 
HGiles said:
JWDODD1,

That is one impressive LC you got! Damn impressive! BTW, I am in Charlottesville, VA.

Thanks HGiles! Does anyone on here know of any Cruiser trail rides that are local to VA. Hope to get her a little dirty in the not too distant future.
 
Yep, speedo is working fine. Picked her up today and drove home fine, but when I shut her off, I heard a gurgling noise. When I opened the hood, it sounded as though the coolant was boiling. I think it may have been on the verge of overheating. Any ideas on what to check to verify?

it depends.... the LS series motors are notoriously difficult to fill with coolant. Most folks recommend removing the upper radiator hose and filling the block until it's full and then reconnecting the hose to the top radiator port.

Then fill the radiator and start the motor and allow it to come up to operating temp with the radiator cap off.

Did your installer make the OBD2 port operational? If so, you can plug a scanner in and it will read out the engine temp. You need a way to get an accurate temp reading to see what's going on.

I use a scan gauge even though my stock in dash gauge is functional. My motor usually runs about 197 with spikes to 200 at a stop light. This is pretty normal since the stock t-stat starts to open at 187.6F and is fully open by 198F. I am switching to a 'so called' 160f t-stat because the hot weather in denver is causing my motor to ping a bit, even with 91 octane fuel. The tuner I used went a little nuts with the tuning he installed - but I like the power so I am willing to try and control the pinging by other means.
 

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