Gen V Engine swap info

[vannatta20]

I started a thread on LS1tech and wanted to pass it on here to help anyone out doing this.

I would like to start a thread where we can all gather basic swap info into the new LT1, LT4, L86, and L83 engines. All the info given below is what I have experienced. I have about 3000 miles on the swap (2008 JK Wrangler) with no issues. So far I have done a few 6.2's and 5.3s. The 8 speed transmission is awesome and the 6 speed is great as well.


1. Fuel pressure requirements- So far the standard fuel pressure of around 57 psi works great. Fuel trims are dead on. Just make sure you have a pump that will support the engines power.

2. Programming- I used hptuners to delete vats and any DTC codes that showed up. Get the matching ECU and BCM from the donor vehicle. You will have issues programming a new OS and VIN if you do not. (BCM needed for transmission control and the brake pedal position sensor) This ECU has so many complex tables be careful of any changes you do. If you use GM SPS service you can not program off vehicle. You will need the ECU, TCU, and BCM at least to program. You most likely will not be able to change the VIN but it will program the new OS.

3. Transmissions- I have only used the matching 6l80e (six Speed) and 8l90e (8 speed) transmissions. Everything works including tap shift and power modes on the 6 speed. The 8 speed I don't have the tap shift working yet. The new transmissions really make this an awesome combo. I would stay away from using any other transmissions. The ECU are extremely complicated and to tune these is much different. With a matching drop out everything will work seamlessly. I did a L86 with a TH400 and it was a huge let down in drive-ability. The new transmissions shift lighting fast and are made to handle the power. Much better gear ratios. the 4.1 first gear is a tire shredder!

4. Accessory Drive- We just added a power steering pump on a truck layout. Holley will offer a kit soon. If using DOD/AFM you will need to keep the vacuum pump.

5. Wiring Harness- I modded the harness myself and is not too hard. Please recommend any companies that currently make custom harnesses. Having it modded will be by far the cheapest and quickest solution. The truck layout looks like a car layout now so it looks much better. The quality of the factory harness is much much better.

6. Fuel pump signal- This is now can bus driven. For now I can only think to use an ignition on for the fuel pump control. The Fuel pump control module is not needed.

7. Fan Control- You can use discrete or PWM. I am using PWM with awesome results. It controls the fan speed based on A/C pressure and ECT. PWM fans that can be used are from the new camaro and trucks.

8. Limp mode issues- I had no throttle without connecting the transmission computer up. If not using the matching transmission that came with the engine you will need to find a manual transmission tune. (If anyone finds a solution please post. GM's swap harness and ECU will not have this issue.Some of the computers do not allow the throttle to move until the engine is running. I see this on the Gen v 5.3. The gen v 6.2 will work without it running oddly.

9. DOD/AFM- It is highly active with the stock tune. At 65 mph it can be in 4 cylinder mode. Cruising around town it will kick in all the time. Its loud and annoying to be honest with loud exhaust. GM tuned the exhaust so you do not hear the change. For now I have it only working on steady cruises. Its not bad with quiet exhaust and makes a big difference in fuel economy. You need to run the GEN V Engine mounts if using DOD.

10. Engine Mounts- It is very important to use factory mounts if retaining AFM/DOD function. The mounts help absorb the extra vibrations. Please list any companies that make conversion mounts.

11. AC- The Factory GEN V AC compressor works great but it is a variable pump. This needs ignition power supplied to it and it will function fine.

12. Cruise Control
Only working so far with a aftermarket controller

On youtube check out the channel WranglerJKLS. Lots of videos with Gen V's running and driving.