Vortex to mechanical 6.2 conversion

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05-22-2019, 20:34
Linhster

Vortex to mechanical 6.2 conversion

Got a 99 Tahoe that I will be doing a conversion to diesel. Would love some insight to any obscure details that I might have missed in doing research for this project.

Original: 5.7 vortex injected 2 door Tahoe with 4l60e.

Conversion: 6.2 TD studded heads with mechanical IP. ESS will be from 6.5 front mounted sensor. TPS is from humvee style TPS with a 5v reference. Hydromatic Power brake and steering. Low stall TC for 4L60e.

Concerns.
- OEM computer to control the 4L60e with lower stall converter.
- O2 sensors (check engine light)
- 4L60E ability to handle the torques without towing
- ABS issues
- speedo
- existing fuel pump over pressuring the IP.

Thanks in advance for any insights .
05-23-2019, 06:26
DieselDavy

There are a few 2 dr Tahoes out there that are already diesel with all of the 'diesel' stuff already there. You might want to start with one of those. Just a thought.
05-24-2019, 03:45
trbankii

Typically, swaps need to be to a same year or newer engine - so a 6.2 into a '99 isn't going to fly.

As Davy says, the 2-door 6.5TD Tahoe/Yukon was available - like my '94. It would be a lot easier to find one of those than go through the conversion. Even if you have custom work done to yours, it is likely easier to swap those items over to a 6.5TD model.

Other than that, they put the 4L80E behind the 6.5TD. A 4L60E could probably live behind a 6.2 (if that happens to be legal in your area), but then you're also talking less power without the turbo. You'll likely notice a drop from the performance of the 5.7 Vortec.

Separate computers are available for standalone 4Lx0E swaps, but cost you money. Without the computer for the mechanical 6.2 there won't be a check engine light. So no O2 and the ABS and speedo will have to be dealt with accordingly - you're not going to have the gasser computer still in the equation. You'll want the diesel lift pump, not the gasser setup.
05-24-2019, 06:06
DmaxMaverick

The N/A 6.5L was available with the 4L60E tranny, but I don't believe the Tahoe was a candidate. The 4L60E is essentially the electronic upgrade to the TH700R4. The correct OEM torque converter is available, but custom is better (and more $$). You could do this with a 6.2L, but a N/A 6.5L would be a much better build.

As you suspect, the electronics will be the bugger. I suggest sourcing a similar year PCM (OBD standard for that model year) and powertrain harness, and have a custom PCM program done to accommodate the features of the Tahoe that aren't optioned in the N/A 6.5L pickup/chassis. The year models need to be similar to accommodate the tranny electronics. Yours is a 99, so earlier models won't work with a later tranny. Research the 4L60E evolution to determine which years can be used. This is critical, as the late model trannies don't live long without effective torque converter lockup control. Simplify the job by sourcing a correct year model Diesel Tahoe that's used up or wrecked. As long as you have all the sensors in place, and the powertrain harness is correct, it shouldn't be that big of a deal. It will also have the accessory drive components that you'll need.

You will want to replace the gasser fuel tank sender/pickup with the correct Diesel unit, and install the Diesel fuel lift pump system. Lift pump controllers aren't cheap, but much advised to simplify the process, and start with a durable system that won't plague you later (because it WILL if you don't).

Go to www.kennedydiesel.com for the lift pump controller and custom PCM calibration, and probably a long list of other things you aren't likely to find easily elsewhere.
05-24-2019, 08:40
DieselDavy

You might want to contact me. I am thinking about selling my 97 2 door Tahoe.
d
05-24-2019, 11:31
sctrailrider

Quote:

Originally Posted by DieselDavy

You might want to contact me. I am thinking about selling my 97 2 door Tahoe.
d

I might be interested....
05-24-2019, 12:04
Linhster

Thank you for all the replies so far... really appreciate the community opinions.

I was hoping for more insight on the untraditional conversions but I guess there are not too many done out there.

Thanks DieselDavy for the offer, I am sure your unicorn will be a coveted one for many and it will sell quickly if you decided to let her go..
05-24-2019, 17:37
trbankii

Quote:

Originally Posted by Linhster

I was hoping for more insight on the untraditional conversions but I guess there are not too many done out there.

There is a whole forum of conversions: https://www.thedieselpageforums.com/...splay.php?f=58

GM diesels into Toyotas, Fords, Jeeps, a tractor, and (IIRC) a Camaro - not to mention GM diesels into classic GMs. Then there are Cummins, Cat, and other diesel swaps into GMs.

Your swap isn't that unconventional - GM actually put a diesel in that model. So it would just be easier to get one of the ones GM already converted than go to the trouble of doing it yourself.
05-25-2019, 09:06
Yukon6.2

Quote:

Originally Posted by trbankii

There is a whole forum of conversions: https://www.thedieselpageforums.com/...splay.php?f=58

GM diesels into Toyotas, Fords, Jeeps, a tractor, and (IIRC) a Camaro - not to mention GM diesels into classic GMs. Then there are Cummins, Cat, and other diesel swaps into GMs.

Your swap isn't that unconventional - GM actually put a diesel in that model. So it would just be easier to get one of the ones GM already converted than go to the trouble of doing it yourself.

Plus the cost of one that is already a diesel will probably be less than 1/2 of doing a conversion,without putting a price on your time:cool:
05-25-2019, 11:59
DieselDavy

"Plus the cost of one that is already a diesel will probably be less than 1/2 of doing a conversion,without putting a price on your time"

That's what I'm thinking too!
05-25-2019, 13:04
sctrailrider

Quote:

Originally Posted by DieselDavy

"Plus the cost of one that is already a diesel will probably be less than 1/2 of doing a conversion,without putting a price on your time"

That's what I'm thinking too!

Sent you a PM....
05-26-2019, 04:23
trbankii

Quote:

Originally Posted by Yukon6.2

Plus the cost of one that is already a diesel will probably be less than 1/2 of doing a conversion,without putting a price on your time:cool:

Exactly!

Quote:

Originally Posted by Linhster

Vortex to mechanical 6.2 conversion

And if the main consideration is the mechanical setup rather than the electronics, just get a 2-door with a diesel and then do the conversion to mechanical injection - much less work than swapping a diesel into a non-diesel vehicle.
05-26-2019, 10:27
More Power

Quote:

Originally Posted by DieselDavy

You might want to contact me. I am thinking about selling my 97 2 door Tahoe.
d

Say it ain't so!

Back to the topic... The TCM computer used behind a gas engine won't work with a diesel... The shift points will be all wrong because of how different the RPM ranges are for the two engines. Jim
05-26-2019, 14:20
Linhster

Quote:

Originally Posted by More Power

Say it ain't so!

Back to the topic... The TCM computer used behind a gas engine won't work with a diesel... The shift points will be all wrong because of how different the RPM ranges are for the two engines. Jim

Thank you, this was the stuff I was looking for. I think you can manipulate the shifting with some adjustment of the TPS but I could be wrong.

I have the following already:

- Tahoe
- refreshed 6.2 diesel (out of a running Humvee) with serpentine belt system
- New Torque converter with 1200 stall
- New flex plate to match
- 6.5 TD side exhaust system with crossover pipes
- Diamond Eye K4108A Turbo-Back Exhaust Kit
- Hydrobooster
- new engergy suspension motor mounts.
- hx35 clone turbo

So... I have already vested into the project. Got the 2 door from a friend but it had 206k miles on the motor. Yes, I can get all the part from a 6.5 but what the challenge in that? :)

And BTW, I have not seen too many 6.5TD Tahoe out there for sale, never mind the 2 door version (Beside what DieselDavy mentioned). And the ones that are for sales would need a freshened up since most of the ones I see have 200k+ miles already on it.
05-26-2019, 17:30
DmaxMaverick

Sounds like you have your mind made up (which is OK), so power on.

You'll actually be doing two conversions, gas to Diesel, then EFI Diesel to MFI Diesel. You can do them simultaneously, but keep them as separate processes in your progress. You'll need late model 6.5L accessory brackets and components (serpentine belt system), which will bolt to the 6.2L block. Once everything is in place and the powertrain and chassis harnesses are correct, you'll need a custom 1998+ 6.5L N/A PCM and calibration to allow communication and control. The PCM is also necessary to communicate with the BCM, which runs most of the chassis components unique to the late models, including the security system (which is another can o' worms).

Quote:

Originally Posted by Linhster

And BTW, I have not seen too many 6.5TD Tahoe out there for sale, never mind the 2 door version (Beside what DieselDavy mentioned). And the ones that are for sales would need a freshened up since most of the ones I see have 200k+ miles already on it.

There are no OEM 4-door Diesel Tahoe/Yukon here. All of them were either exported, or built out of country (Brazil). None were ever delivered here. If you see one, it came into the country from somewhere else, or it is a conversion.
05-26-2019, 17:45
DmaxMaverick

Also, the HX35 is too much turbo for the 6.2L. There's much discussion here about that. It's just too big for the 6.2L operating margins. If you TD it, you'll need HX30-ish size non-wastegate (Banks), or GM4/8 wastegated.
05-27-2019, 04:35
Linhster

Thank you DmaxMaverick for the insightful tips... I will definitely look more into those items you have brought up in discussion..