duramax performance

[cjohnson]

I know many have talked about this and I also know it is hard to campare the Duramax to the Cummins. But I am curious what the technical reasons are that a Duramax can obtain so much performance with only fueling enhancements. I would suspect that the stock turbos in that motor are subject to being pushed beyond their map just like the holsets in our trucks. So how is it that they can continue to make power beyond a given point without exceeding the limits of the stock turbo. Obviously the motor is able to efficiently combust large amounts of fuel even with the limitations of the stock turbo. Obviously at some point, they will and do exeed their limit, it just seems to take quite a bit more than what our 5. 9 do before requiring turbo upgrades. All this being said, even though a lot of power is easily achieved through fueling upgrades alone, it also appears their isn't much room left to go after that. Otherwise I suspect we would see lots of upgraded turbos and such. Anyway, I am looking for some technical responses from those who know, not just a bunch of bickering. This is just to satisfy my curiosity.



Thanks,



Craig

 

[mfunderburgh]

Don't have any answers for you but just wanted to let you know that they are coming out with turbos now. It will be interesting to see what the duramaxs will do with some aftermarket turbos. They are very impresive trucks with just stock turbos and stock engine parts and some fueling upgrades. Matt

 

[cjohnson]

Yeah, I figured the turbos were coming. I just wonder how much they can benefit from upgraded turbos as some aspects of the engine design seem to be at their limit as it is. Where there is a will there is a way. I'm sure they will come up with ways to squeeze everything possible out of it. Still wonder how they get so much from the stock charger.



Craig

 

[Big P]

They are substituting a bigger turbo for NOS. The current turbos don't supply enough air, so they are shooting the NOS to burn it.

 

[Ncostello]

Its a VGT turbo for the 04 LLY engines. Plus other major changes have been made making them far superior to the 03's and older.

 

[Breck]

Over square motor that likes to rev. I am pretty sure that the short stroke, revs and common rail have a lot to do with why the dmax does well with just a box.



You will notice that the OTR tractors are not going to an over square v-8 for performance/durability.

 

[CSilkowski]

Does anyone know what #'s these Duramax's are putting out with fueling boxes? I got SPANKED by one the other day. Cruising together at 80 mph up a 7% grade and he walked away from me like I was stand'in still. Bummed me out the rest of the day

 

[robertyoke]

Originally posted by CSilkowski

Does anyone know what #'s these Duramax's are putting out with fueling boxes? I got SPANKED by one the other day. Cruising together at 80 mph up a 7% grade and he walked away from me like I was stand'in still. Bummed me out the rest of the day

call tst and you will do the spanking

 

[Forrest Nearing]

they're definately runners empty... as stated above, they've got a rev-happy V8... RPM = horsepower, that's all there is to it...



that's about all they've got going for them though...

 

[mfunderburgh]

I think the combination of the allison transmission and their motor is a very good combination. If you call tst you had better hope they didnt call quadzilla and have gotten a stealth(215hp)tuner. I've road in a truck with a tst box and a stealth tuner. Very impressive. Ask dave mitchell what he thinks. He was in the same truck and i think he was impressed. I think its more than just rpms too. My truck will rev close to 5000 and when i had an auto in it it wouldnt run with that dmax that could do 4500rpms. Their trannys just seem to keep them in thier power band better. Matt

 

[jwinnie]

Originally posted by robertyoke

call tst and you will do the spanking

No doubt about it!!!

 

[Buffalo]

I have a buddy with an'03 Duramax/Allison. He had a Duramaximizer and a Duramaximizer Tech. 4, with a K&N Filter system and guages installed. He says it's supposed to have 525 HP , now. It seems to be fast, but he's on his second allison, now. Apparently, there is a sensor in the trans that senses an over-powering situation in fifth gear and locks it out. I guess you have to turn the truck off and it will reset itself. He's, also, had the pyro up to 1550 deg's. A little too hot for me. If you have one be careful not to over power it. Joe.

 

[lmills]

bully dog also has a 220 hp setting on their programmer for the duramax's

 

[cjohnson]

So it doesn't seem that anyone really knows why it is that the Duramax is able to attain the power levels it does with just fueling boxes and the single, stock turbo. I know that for us to make 500 horse on the B motors using the stock charger is pretty much unheard of. It seems there are a fair number of Duramaxes doing this. How are they burning all that fuel especially with a single stock Charger? Apparently the common rail injection system is flexible enough to provide the fuel, that I can accept, but how are they burning it with that charger? Obviously the stock charger isn't all that big as it doesn't have a lag issue. So what gives? And no I'm not thinking about getting one, I'd never have anything other than the B, I'm just curious. Must have something to do with the efficientcy of the heads/combustion chamber. Because they don't run the high boost numbers either.

 

[NPloysa]

Good question. Are there even any fueling boxes that go past 150 HP for an ISB? I know Common Rail is different but wow, I thought my box at 120 HP was nice, I can only dream of a 250 HP version...

 

[lmills]

I heard from one of the bullydog vendors that they were working on a programmer for the new common rails that would work the same as the programmer for the duramax. Supposedly it would be able to download your stock program and reload a hotter program. The vendor is usually reliable so I bellieve him, just never checked with bullydog to verify it. By eliminating the stock program they would be able to control the CEL's. I also heard of a possible 200-220 hp. Who knows, it could have just been talk. That was about 6 months ago when he told me that.

 

[Rebel_Horseman]

Well here's my opinion form when I had my Dmax running the regular Juice.



The module works with the injection system and advances the timing somewhat and adds gobs of fuel to make more power. The injectors, much like the injectors of the ISBe trucks, can atomize the fuel and add the fuel more precisely than the 12v & 24v trucks. With the regular Juice module I had, the power levels were 40, 60, 75, & 90 hp with the 90 hp setting adding 250#'s at the rear wheels. The 120 setting on the Hot Juice added a little over 300 I think. I fully expect to see similar things to be available for the new generation of ISBe trucks. I know for a fact that with the box on Level 4 I could spank a Mustang GT and hang with Z28's. It was simple to get my mud tires to spin out... just powerbrake to build a few pounds of boost, dump the brakes and stomp on the fun pedal and 1st and 2nd gears were nothing but tire spinning smoke shows. It was a very fun truck to drive, and had I not had fuel system problems with it, I would still have it. The Allison defueled between shifts, as well as defueling if slippage was detected.



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[Big P]

Like I said before, nitrous. I don't think, not positive, that the Duramax can run over 500hp without it. Their boxes can dump alot of fuel into the motor but the turbo CANNOT supply enough air to burn it. That's why they add NOS. It's like O2 in a bottle. Also a motor with a larger displacement doesn't need as much boost as a smaller motor, it already has more cylinder volume.

 

[DavidTD]

The Duramax can run over 500 without NOS. I have seen a best of 525, and I have seen over 500 many times.



IMO, Aside from the Common rail fuel system and slightly larger turbo than a factory HX35, they have more cubic inches. We use boost to make up for the smaller displacement. Yes they run high EGT's and yes they run well on the track.

 

[Big P]

I was close.