Capote's 4.2L Rear-mount Turbo Build

Capote

Platinum Supporter
#1
The regulars are aware of this already, but i'm planning a Turbo build with the aid of an experienced friend. Decided to go the unconventional route and go for a rear-mount setup for a few reasons: to keep engine bay temps down, retain A/C, utilize airflow underneath the vehicle to aid the intercooler by further cooling down the exhaust (therefore making the air temps a bit lower before entering the engine), and to keep as much space up front as possible.

Why am I going Turbo?
Because I honestly don't want to do just another 5.3 swap. Yes it's a much simpler having helped a close friend do-so on his TB a few months ago, but power-adders for a V8 are more expensive. Yes, you can get even more power, there's plenty of parts, how-to's, and documentation out there, but what about guys like me whose pockets aren't too deep? I also want to be part of the small number of 4.2 enthusiasts out there to have a Turbo'd 4200. Some guys call this engine the "American 2jz" These engines have a lot of power to offer, that power depends on how much you want to spend to get "X" amount of power.

What Turbo are you using?
Small frame GT37, really suited for a remote setup like this.

What kind of power am I seeking?
400-500HP range, running anywhere from 8lbs to 14lbs of boost, 8lbs daily driven. The donor motor I have to get ready for this build is a 2005, out of a TB with roughly 170,000 miles IIRC. This motor was well taken care of and maintained vigilantly. Most of all internals are being replaced with new GM, Mahle, or Clevite brand ones.

Forged internals?
I could not find any forged bearings or rods readily-available, so i'm just going to replace the bearing with bi-metal ones that Mahle has. The reason for me not getting forged parts is due to the lack of their existence, since there is nearly nothing aftermarket-wise available for this engine to begin with; as well as pricing for having them made custom. $1700* for a set of pistons and rods. We know that a 4.2 with bone-stock internals, average mileage & wear can handle Methanol Injection and up to 17lbs of boost, albeit that's not what you'd normally run everyday obviously on a street-driven vehicle: http://vortec4200.com/forum1/viewtopic.php?f=10&t=798 - Quite an informative & interesting read-through. So all-in-all i'm not as worried as I once was about internals.

Lower compression pistons?
I haven't researched into that aspect yet. But I can't imagine those being cheap to be made-up.

Plans for after this project is complete?
Bring it to the 1/4 mile track every month or so to have some fun and to get some spot-light on the GMT360's again as well as the Atlas LL8.

This build is not going to be anything quickly moving, i'm still in the process of getting all the parts for the 2005 engine for the 1st phase of this project. The first phase will be getting the donor motor freshened up with new parts, swap in the donor motor with Kooks headers I have waiting to go on. I am also converting over to Efans with a larger capacity Mopar aluminum radiator. Once everything is in place and the motor is running fine we can swap the PCM for a 2006 one, and wire that all together with the '05 harness. I just want to ensure the engine is operating properly prior to switching over to the '06 PCM and accompanying MAF sensor. Once the '06 PCM and everything is operating correctly I can go ahead and install the 80lb fuel injectors and have the '06 PCM relearn idle. Once this phase is complete, we can move on to the second phase and focus our attention to the Turbo aspect, the whole point of this build. Figure out the best location to mount the Turbo, scavenge pump, run oil lines, best places to tap into block and/or oil pan, install intercooler & intercooler piping, install BOV, run colder plugs, figure out a warning system in-case the pump fails, etc. Then lots of tuning and testing until everything is dialed in and we have everything running smoothly.

Any comments and suggestions as this projects progresses will be highly appreciated. This thread will eventually be full of pictures, knowledge, and insight to share as it continues.
 
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OP
OP
Capote

Capote

Platinum Supporter
#2
Garrett GT37 w/ Red Powdercoat
IMG_20170917_230231.jpg
Limeswap's EV6 Injector Connector Harness
IMG_20171207_011731.jpg

Spare valve cover to be used on Turbo engine, painted in Rustoleum Gloss Black Engine Enamel so it's oil and fuel proof:
IMG_20170329_032016.jpg

Turns out I painted this over a year ago, when looking at the picture timestamp.... time flies...
IMG_20170329_032104.jpg
 
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MRRSM

Lifetime VIP Supporter
#3
Re: Forged Internals...

I know you've already visited this link... but for others closely following your Bat-Turbo-Engine-Build and still very curious about the existence of any High Performance Con-Rod Set:

https://gmtnation.com/forums/threads/after-market-hp-con-rods-for-gm-4-2l-ll8.16552/

...and quite a while back... I picked up this Complete Set of GM OEM Quality Mahle Pistons and Wrist Pins via eBay for under $70.00 from an LLC who apparently did not understand what they really had... and perhaps there are still a few sets of these available. What might also prove helpful about this link is that my Photobucket images regarding the Complete Piston Specifications can be used for referencing other Vendors who may be producing Forged Aluminum Slugs for your Build:

http://s557.photobucket.com/user/60...RENGINEREPAIR/GMMAHLEOEMPISTONS?sort=3&page=1

I would recommend using the appropriately sized "Howards Cams Spirolocks" for the better retention of the Wrist Pins vs. using the stock "C" Half-Moon Spring Clip Locks.

So Far... So Good, Brother...

For anyone who wants to visualize rather than just imagine what all of this "Easy Breathing" Turbo-Charging Hardware Looks Like Under the Hood ...and on the Engine ...Take a gander at THIS Article. It might be nice for @Capote to be able to email the Original Builder on this Project and get some additional empirical performance information ... Directly from The Horse's Mouth:

http://www.hotrod.com/articles/ccrp-1108-turbocharged-vortec-inline-six/
 
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OP
OP
Capote

Capote

Platinum Supporter
#4
Re: Forged Internals...

I know you've already visited this link... but for others closely following your Bat-Turbo-Engine-Build and still very curious about the existence of any High Performance Con-Rod Set:

https://gmtnation.com/forums/threads/after-market-hp-con-rods-for-gm-4-2l-ll8.16552/

...and quite a while back... I picked up this Complete Set of GM OEM Quality Mahle Pistons and Wrist Pins via eBay for under $70.00 from an LLC who apparently did not understand what they really had... and perhaps there are still a few sets of these available. What might also prove helpful about this link is that my Photobucket images regarding the Complete Piston Specifications can be used for referencing other Vendors who may be producing Forged Aluminum Slugs for your Build:

http://s557.photobucket.com/user/60...RENGINEREPAIR/GMMAHLEOEMPISTONS?sort=3&page=1

I would recommend using the appropriately sized "Howards Cams Spirolocks" for the better retention of the Wrist Pins vs. using the stock "C" Half-Moon Spring Clip Locks.

So Far... So Good, Brother...

For anyone who wants to visualize rather than just imagine what all of this "Easy Breathing" Turbo-Charging Hardware Looks Like Under the Hood ...and on the Engine ...Take a gander at THIS Article. It might be nice for @Capote to be able to email the Original Builder on this Project and get some additional empirical performance information ... Directly from The Horse's Mouth:

http://www.hotrod.com/articles/ccrp-1108-turbocharged-vortec-inline-six/
Thanks for the info and once again providing links to your Photobucket. I've actually come across this article before on HotRod.com and have it bookmarked. I'm loving that custom intake manifold. I might be upgrading my fuel pump like he did. I have some Walbro ones saved just in-case.
 

MRRSM

Lifetime VIP Supporter
#5
Without knowing whether or not you have pulled off the Crankcase-Oil-Pan off of The Donor Motor yet... I wanted to mention my concern about the matter of the dynamic motion of your vehicle... lurching off the line in a Drag Race...and if your Oil Pan is without a Proper GM OEM Oil Baffle in-dwelling... you could run a serious risk of two problems ruining your Project Turbo Build:

(1) When the Christmas Tree Light pops "Green"...and you go... The Oil inside the Crankcase will tend to shift and slosh suddenly upwards from the Deep Well of the Oil Pan and rapidly rise like a Wave up the steep incline in the back of the Oil Pan and to the rear... thereby possibly making Direct Contact with the rapidly Rotating Assembly and causing the Crankshaft Throws and Counterweights to whip that Mass of Motor Oil into a Useless Brown Froth that will resemble something like Beaten Egg Whites in a Blender.

(2) If this occurs... Oil Starvation is only momentarily away as soon as the Oil Pump Pick Up Tube attempts to suck that Brown Froth up inside of the Gerotor Oil Pump ... and it stops functioning as a pump. The Gerotor Oil Pump can only pump a straight, solid stream of incompressible Liquid Motor Oil. But if that life giving liquid becomes this Foamy Oil Froth ... Then the Gerotor Pump will simply squeeze down upon the Air Bubbles in the Oil Foam and the Maximum Oil pressure that should be at 65 PSI will suddenly drop to "0". If this happens ...instead of moving around 11+ Gallons of Oil Per Minute through the Engine Oil Galleys and Bearing Surfaces... they would rapidly heat up from Friction via Metal on Metal contact and this would unfortunately doom any motor under such conditions of approaching 7,000 RPM in a Racing Build with No Oil inside to protect everything from harm.

When you perform your Tear Down... Please compare what you discover down inside your Crankcase as either having an In-Dwelling Oil Baffle as depicted in these attached images... Or Not. If you find anything contrary to having this Necessary Baffle being riveted in place within your Crankcase-Oil-Pan... please let me know:

http://s557.photobucket.com/user/60...NEREPAIR/TRAILBLAZERENGINEPARTS?sort=2&page=4
 
OP
OP
Capote

Capote

Platinum Supporter
#6
That was a concern of ours as well. I know the TBSS guys have an aftermarket baffle available to fix their issue with oil starvation during launches. If there is no baffle, I'm sure my friend can fab up a modification to the oil pan to include one.
 

MRRSM

Lifetime VIP Supporter
#7
If it comes down to cases... Never mind the effort to fabricate one... I'll just give you the exact Crankcase-Oil-Pan shown in those images. Just think of of it as being my contribution to your Turbo-Charged Bat-Blazer... If yours turns out to be 'naked' down inside ... Just say the word here in this thread and after posting some images of it... send me a PM with your particulars. I'll cover the cost of the S&H of it as well. You know... We ALL want you to succeed here... in a very big way, Brother. :>)
 
#8
I don't know how the oil pickup tube in the I6 oil pan is, but I think one of the best things you can do to prevent oil starvation at hard launch is relocate the tube. This extends the pickup towards the rear of the pan instead of the front stock location.
 
OP
OP
Capote

Capote

Platinum Supporter
#9
If it comes down to cases... Never mind the effort to fabricate one... I'll just give you the exact Crankcase-Oil-Pan shown in those images. Just think of of it as being my contribution to your Turbo-Charged Bat-Blazer... If yours turns out to be 'naked' down inside ... Just say the word here in this thread and after posting some images of it... send me a PM with your particulars. I'll cover the cost of the S&H of it as well. You know... We ALL want you to succeed here... in a very big way, Brother. :>)
That'd be much appreciated buddy.
I don't know how the oil pickup tube in the I6 oil pan is, but I think one of the best things you can do to prevent oil starvation at hard launch is relocate the tube. This extends the pickup towards the rear of the pan instead of the front stock location.
The pick-up tubes are pretty cheap, so it wouldn't hurt to experiment modifying one to do-so. Good idea.
 

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