This could be a long shot thread, or this could lead to something remarkable.
After over a year of searching for the proper turbocharger for my TowBoss build, I'm just about to throw in the towel and start learning how to modify these turbos to craft a one-of-one turbo for my rather specific application. The goal of this build has always been break 500RWHP with a solid race file, and dial in a stock level file for heavy towing at high altitudes (26K Gross, and over 12,000 ft) and be drivable on Ford's programming (though this last requirement there is starting to fall lower on priorities list). I was looking strongly at the MTW Stage 2, however it has since been discontinued.
I'm getting to the point where a turbo supplier, any supplier, doesn't seem to have exactly what I am looking for, or has an excessive wait time, etc. I feel that with my schedule, building my own solution that I have full control of makes more since. That is, if the project can be considered achievable.
Current Market Offerings:
So we take the stock turbos specifications:
Stock (GT3782VA)-- Comp: 59mm x 82mm T-52 (03-04s) 57mm x 82mm T-__ (05-07s) .58A/R -- Turb: 72.5mm x 64.0mm (05-07) (72.5mm x 66.4mm, 03-04 and 13 blades on both) T-78 .90A/R
And we look at what is on the market currently that falls into the level of my build:
MTW Stage 1 LBZ (Discontinued)-- Comp: 62.8mm x 88mm T-51 .58A/R -- Turb: 72.5mm x 64.0mm (Or 72.5mm x 66.4mm, both 13 bladed turbines) T-78 .90A/R
MTW Stage 1 LLY (Discontinued)-- Comp: 63.5mm x 88mm T-52 .58A/R -- Turb: 72.5mm x 64.0mm (Or 72.5mm x 66.4mm, both 13 bladed turbines) T-78 .90A/R
MTW Stage 1 -- 63.5mm x 88m T-52 .58A/R-- Turb: 72.5mm x 64.0mm (Or 72.5mm x 66.4mm, both 13 bladed turbines)T-78 .90A/R
MTW HYBRID -- Comp: 64.7mm x 88mm T-54 .58A/R -- Turb: 72.5mm x 64mm Or 72.5mm x 66.4mm, both 13 bladed turbines
MTW Stage 2 (GT4088)(Discontinued)-- Comp: 64.7mm x 88mm T-54 .72A/R -- Turb: 72.5mm x 64mm Or 72.5mm x 66.4mm, both 13 bladed turbines
Garrett Powermax -- 63.5mm x 88m T-52 .58A/R-- Turb: 72.5mm x 66.4mm 10 bladed turbine.
MTW Powermax -- 64.7mm x 88mm T-54 .58A/R Comp: -- Turb: 13 or 10 blade 72.5mm x 66.4mm
Peixinhos 68mmKC -- Comp: 67.8mm x 94mm T-59 .58A/R -- Turb: (Unknown)
MTW Stage 3 (GT4094)-- Comp: 67.8mm x 94mm T-52 .58A/R -- Turb: 77mm x 68mm Larger than Stock GT40 Series - 10 Blade)
I list the MTW Stage 3 here, because of the reduction of back pressure with this larger turbine wheel over that of a 13 blade GT37. This is a very interesting aspect of this, and if there are 13 blade versions of larger turbine wheels available they will be investigated (not sure if there even is any). This would be the absolute upper limit tier built turbo for this truck, based on a max injector of 155/30s(or stock nozzles). It is something for me to look at, but I am leary of a compressor that large with small injectors.
The other aspect of the Stage 3 is the possibility of clipping the wheel a bit, raising the trim value and seeing what happens. Say clipping it to a 67.8mm x 88mm T-59. Pitfall of this plan is getting every blade trimmed perfectly without any structural stress, and maintaining a balanced wheel.
An interesting Alternative(s):
There was another idea suggested to me quite a while ago, looking at a GT35 series wheel:
Random Idea -- Comp: 62.5mm x 82.5mm T-58 (from GTX3582R) .58A/R -- Turb:68mm x 62mm T-84 (from GT3571Va-early F450/F550 trucks)
Could theoretically mate this compressor to a my stock turbine with some machine work and see what we end up with. The compressor maps as I look at them seem very positive that it would be a great set up - though final power numbers may lay slightly shy of the 500RWHP goal. This is a smaller wheel that the current MTW Stage 1, really a minor gain over the stock compressor. Mating this wheel to a GT37 series turbine could make it a viable towing option.
Reading over Adrian's thread I have another promising concept turbo, a re-creation of the MTW Stage 2:
GT4088 for Baseline-- Comp: 64.7mm x 88mm T-54 .72A/R -- Turb(Preferred): 72.5mm x 66.4mm T-83 .90A/R (From an '04) Or Turb(Alternate) 72.5mm x 64mm, both 13 bladed turbines T-78 .90A/R (From '05-'07)
--Or taking that one step further (depending on what my Back Pressure would look like and how the truck would respond):
GT4088 for Baseline-- Comp: 64.7mm x 88mm T-54 .72A/R -- Turb: 77mm x 68mm Larger than Stock GT40 Series - 10 Blade)
Take that GT4088 and mate it with the turbine out of the GT4094, would take considerably more machine work and expense (follows a similar concept as the GTX35 series idea). And I may run into a similar problem - simply too much surgeing / or too much lag.
Stock and Powermax Compressor Map:
GTX3582R Compressor Map:
GT4088 Compressor Map:
GT4094 Compressor Map:
Stock Turbocharger in great shape: $450.00 Remanufactured: $xxx.xx
Garretts Rebuild Kit with 360* thrust bearing: $160.00
Billet Upgrade Wheel of the size chosen: $400.00
Machine Work on the Compressor/Wheel: (Unknown)
Balancing of the Compressor and Turbine Wheel: $65.00
Where it could get worse:
GT4088 Compressor housing: $xxx.xx
Powermax Compressor housing: $xxx.xx
Trimming a Billet Wheel: $xxx.xx
--Doing the whole job over again because something doesn't go right the first time, or the turbo build is too large / too small for my application (which simply results in me selling the prototype and starting from the bottom).
The Way this whole project would come together:
-Find a low mileage Stock turbocharger for the right price.
-Initial Inspection, and Cleaning.
-Upon reciept of the correct wheel, and compressor housing (if required) get the machine shop to conduct the required modifications to the compressor housing / wheel (as well as shaft if required)
-After all parts are on hand, rebuild the turbo with the Garrett kit, and prepare the turbo for installation.
-I intend to have solid numbers for each stage of this thing, so this is where I would go get the base numbers for my stock setup, running my current race file, and Fords programming. More to follow as I get to this stage.
-Install the new turbo, get the relearn process complete, and get the initial numbers for the truck under Ford Programming. This gives us the initial progress of the gains made without adding programming (which is at this point somewhat expected), and on the stock Intake Manifold and Air Filter (Yes, even going to get some testing with an aftermarket air box).
With each set of changes I decide to make, or for those attempts that fail completely - I'll keep the thread up to date.
For the ORG:
So, I'm looking for input from members on the ORG as to holes in my plan. See what others have done without simply running 'Insert Brand Here's" Stage "X/max" 'charger.
I'm just getting comfortable at least understanding the theories behind what makes a specific 'charger work. I realize though there has got to be something out there I am overlooking.
Also, if there are members/vendors that come across this thread and know of additional wheel sizes, compressor or turbine side that are in this range, be sure to bring them up.