In two weeks the H1 will be getting a new 6.6 Dmax and Allison 6spd transmission and a stage 1 predator kit. Will be shooting for between 450-500HP and close to 1,000trq.

Those of you who have a 6.6 or work on one,How reliable does this HP sound for a daily driven truck? Anything to look out for? What should I know about this motor? Diesel/heavy duty trucks are completely new to me, so any info will be appreciated.

 

I hate you.

 

I know an Allison 6 spd transmission is about as good as it gets for a truck. Not sure about the duramax though. Sounds like it's gonna be a beast.

 

No experience with a diesel? Torque is addictive.

 

Yeah so far I love having power down low. It just needs more of it!

 

EFI live tune and DSP 5 position switch and you can run what you are looking for all day. Idaho Rob is who you are going to want to get the tunes from, he tunes a ton of duramax trucks. Get something to monitor injectors, sounds like you are planning on a new duramax though. It is not necessary to build the engines, if you are looking for a built engine I may know where there is one.

 

Sean, I DD a modified diesel truck (an F-250), but here are some modified diesel basics;
- Make sure you have an EGT (Exhaust Gas Temp) gauge istalled. Rising EGT's will destroy your turbo and factory settings on these motors are set to be "idiot proof" and will protect the motor no matter how hard it is being hammered. Modify them, and they dump more fuel in, and if a sufficient amount of air is not being pushed into the motor to burn that fuel, EGT's will rise quickly and fry your turbo. Install the gauge where it is visible and watch it constantly.
- Also have a boost gauge installed. Boost is the best indicator to how your engine is running. For instance, if you typically make 28lbs of boost and all of a sudden you are only making 20lbs, something is wrong and needs to be checked out ASAP.
- I would also install a trans temp gauge. The extra power will put lots of strain on your tranny and heat is the primary indicator that something is going wrong with it.
- Most chips/programmers add fuel and change the fuel delivery timing, so you need to take the proper measures to ensure you are getting enough air through the motor. That means upgrade the intake and exhaust.
- Be careful not to be too aggressive with your programmer. Too much power can blow the head studs and shred the tranny very quickly.
- Be sure the have the transmission valved properly for the amount of power your are making. This is typically done with a valve body kit which are not too expensive and don't take long to install.

These are a few of the basics. Hope they help. cstroked also knows quite a bit about modded diesel trucks, so he may chime in as well.

 

Ditch the Diablo and go EFILive like yzracer mentioned.

Make sure you have a free flowing exhaust and CAI. What year is the H1 (I forget which years the Alpha was in production)? This will determine the types of emissions equipment it has - this may or may not require mods

SoCal Diesel is a great Dmax shop close to you. Merchant Automotive is great but they are in MI. If you're looking to do something from the tune to a full build that's who I would recommend.

I don't think with a tune you're going to need to worry about too much if you get into the injectors etc you're going to want to make sure the injector cups are good to go. SoCal Diesel would be able to tell you more, but if you go with a hot tune you will also want to make sure the LP fuel pump is up to the task because the CP3 high press pump is lubricated by fuel not by oil, so if the low press fuel pump is subpar relative to the amount of fuel the tune calls for, you can fry the CP3. Airdog, FASS (I run a 200gph FASS on my Ford), or Fuelab make great pumps. The first two are fuel/air/water separators and the Fuelab is a traditional pump, but is brushless so the durability is probably the best on the market of the electric pumps.

Once you get into the higher HP the duramaxes have been known to lose injector cups and chuck rods. I don't care what anyone says, it will happen. Also notable is that 85% of the failures in the diesel world are kept quiet and off the net due to many of the people involved behaving like ricers with PMS so it's best to talk with reputable shops not individuals. If you're staying at or under 500rwhp (all figures I reference are in rwhp - diesel world works off of rwhp not crank hp) I wouldn't worry too much though, anything beyond 600 I would look into studding the heads, 700whp I would consider billet rods and a girdle to prevent cap walk which is inherent in V8 diesels due to their V design (compared to I6).

MPI (Maximized Performance) makes nice twin turbo kits using the stock turbo as the high pressure in the set up, not sure how much of this type of stuff translates from the pickups to the H1 though.

My advice is set a reasonable goal and be happy with it. It gets labor intensive and expensive FAST.

 

I think you guys misunderstood me. It's going to get a completely new motor, tranny, pretty much a new drive train. Predator motorsports is doing the work, they have done more H1's than anyone. But I want to make sure that the numbers sound reliable for I know nothing about the 6.6. Unfourtuately I don't have specifics on what they are doing to get the numbers. I'll make sure to get plenty of photos of the build.

I will also make sure to get extra gauges set up for temp watching.

Thanks guys.

 

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