LS4 V8 Engine Swap

[Leon R]

The issue was that the EVAP system has to be as it was from factory, on the vehicle that the engine came FROM.
It can't throw a CEL, and the EVAP can't be deleted by a tuner.

Agreed! Pretty sure that this is a federal requirement for ALL states! What differs from state to state is the enforcement of such laws!

So, in order to get that to work, the gas tank from the donor vehicle would need to be transplanted into the VX with all EVAP systems attached and functional...

But this is where were we disagree Rules and regulations can be interpreted in many different ways (I am pretty sure that they made a profession out of this ). While your interpretation is correct, it is probably THE most difficult way of achieving desired effect!

Instead of transplanting an ENTIRE fuel system from the donor vehicle you need to understand how EVAP system works in the donor vehicle, compare it to VX's EVAP system and then figure out a way of making they play together! Most of these systems work in a very similar manner, so a simple purge solenoid valve swap might do the trick! Considering that Isuzu used many GM parts, you might even find that the two are compatible.

The bottom line, you want to make GM computer happy and CE light free! There are MANY different ways of achieving this without transplanting 100% of emission controls from the donor vehicle (which is impossible!). Are they 100% legal in a full sense? Probably not, as they weren't designed by GM to work together. But no one is going to apply THAT level of scrutiny to your project!

Have you tried talking to others in your state, who have performed an engine swap?

[SilverBullet75]

Yes, I talked to a couple tuning/mod shops actually. But the difference is that ALL of their customers that did a swap did it in an OLD vehicle that doesn't have the requirements applicable. None had done it in a '96+ vehicle where the rules are completely different.

I had thought about trying to fit the donor equipment to the VX as you said.
This might work. But, I don't have the knowledge required to do this.

Now, if you want to take point, PLEASE DO
I would love to start this project up again, but this time with an LS1/2/4!
(BTW... I too looked into the LS4. VERY interesting option.)

[bartmanS4]

Will it be possible to maintain the TOD or would this require a manual transfer case? I know the TOD has it's own computer but I have no idea how this interacts with the ECU. I think this would be a really cool swap and if not too complicated provide a good alternative to our standard power plants as they get older and older.

I my opinion the emissions standard should simply be: does the vehicle pass the individual output tests period. My guess based on, well nothing, would be that this would achieve a more efficient power plant solution resulting in lower emissions.

[SilverBullet75]

GREAT point! TOD would be disabled if I understand correctly. The VX or Trooper 5Speed computer is required to run it. In that case, wouldn't you be forced to go 5 speed anyway? Does the 4L30e receive input from the engine's computer?

[SilverBullet75]

Wait... I don't know WHAT I was thinking...
Scratch that last post.
The engine's computer doesn't control the TOD...

But, it does control the transmission, does it not? That's why there's two versions... Manual and Auto.

[BigSwede]

GREAT point! TOD would be disabled if I understand correctly. The VX or Trooper 5Speed computer is required to run it.

FWIW, 5-speed Troopers do not have the TOD transfer case.

In any case if I were you guys I would look at a different tranny than the 4L30E...

[Leon R]

FWIW, 5-speed Troopers do not have the TOD transfer case.

I know that it is a bit off topic, but what type of transfer case do they use?

[BigSwede]

I know that it is a bit off topic, but what type of transfer case do they use?

I think the 98+ 5-speed Troopers use an Aisin, don't recall the number.

[clipper 03 rodeo]

In any case if I were you guys I would look at a different tranny than the 4L30E...

My Rodeo doesn't have the 4L30E in it, mine has the better Aisin auto used in the 04 250hp Direct Injection Rodeo/Axioms. So I don't think i'll have any issues with it since it will only be about 50hp more than what the DI Rodeos came with.

[clipper 03 rodeo]

Well after chatting with some LS4 guys, they recommended I go ahead and use the GM 5.3L truck engine along with the matching tranny. Mainly because it would simplify the wiring greatly by being able to control the engine and trans from the single GM ECU instead of using a standalone system, it would cost quite a bit more and would require custom programming going that route. I was thinking maybe I could just use my Isuzu ECU to control the tranny alone and using the GM one to control the engine functions, but it seems like it's more complicated than to make everything work correctly.

So i'm thinking i'll just go the truck 5.3 route since it would be pretty easy for me since my Rodeo is only 2wd, the main thing i'd need is a custom length driveshaft and mounts to make this tranny work in my rig with the stock GM ECU.

P.S. The LH6 GM 5.3 V8 has an aluminum block, not iron compared to the LY5.