Drove a Durabux today.....

[Dvldog 8793]

Test drove a 2003 duramax today for a friend and can say that I was not real impressed. I am fairly sure that my 6.5 would walk all over it. Maybe this truck was just a dog??? Anyway it sure made me feel good to get back in my '99 6.5 rattle wagon :D
L8r
Conley

[RT]

I drove one that had a Diablo chip, exhaust, intake, etc. Bloody thing was like a NASA rocket ship. Too bad it cost as much too. 40+K for a truck is a joke. I'll be driving old reliable for a while yet. RT

[LanduytG]

I am fairly sure that my 6.5 would walk all over it Think you need to go ride in it again. I can tell you that a stock Dmax will flat walk away from a 6.5TD. My son has my 6.5 now and I still drive it from time to time. When I get out of it all I can say is what a slug it is.

Greg

[markrinker]

My truck #2 performs on par with a stock Duramax. I have tested both on the same 25' trailer loaded with two skidsteers.

Personally, I wouldn't miss my old 1994 with the bench seat and foam innerds leaking out under my butt. A Duramax with the LS package would be great!

[Dvldog 8793]

Howdy
Guesse I should clarify.... My truck(4.11) is fairly maxed out and the Dmax was COMPLETELY stock with 3.73 gears. BUT my truck still has about an extra 1000lbs to drag around. I suppose I would say that the two were pretty close to equal with my '99 having a slight advantage. I suppose if the same amount of mods were done to the Dmax then I could probably take it to the local NHRA races! :D
L8r
Conley

[Govt issue]

The only thing that i don't like about the d max is that the trans seems to shift all the time. My 4l80 lets you lug threw the gears a little more. Although most of the trucks that i have driven are 8.1 the diesel may have a different shift pattern. I like to crack the throttle to half way and just feel the tq. The allison feels like a school bus i drove once. although i havent got much expercence with the diesel.

[LanduytG]

My 95 is not stock by any means. I have large injectors with big IC, exhaust, gear drive, BD chip and run 12 psi boost. It does very well but still not up to my stock LLY. During the pull off last year ronniejoe pulled and was slower than my stock LLY. And Ronnies 6.5 is not stock.
Ron ran a 42mph at 1 min 42 I ran 51mph at 1 min 19. We both ran late and in the heat of the day. Another member with a stock LLY pulled a 53mph at 2 min 17.

Here is the link to the 2004 Pull Off. (http://www.thedieselpage.com/features/pulloff04.htm)


Greg

[rjschoolcraft]

Greg,

The actual time for my run was 1:22.

I wish I had that to do again, because I'm sure it could have been better. At best, I might have equaled your stock D-Max.

I had reached 47 mph and should have shifted into direct, but did not. As rpms continued to climb, my boost fell back and I lost speed.

This is not to take anything away from the point you're trying to make here because I think it is valid. Just clearing up the small discrepancy and giving a little extra insight.

[Kennedy]

On a good day, my 96 would run about on par with a stock Duramax. With the OE turbo, the bottom end was good, but top end suffered. With the Peninsular turbo, the bottomend suffered, but the top end was now fairly decent.

The Duramax just flat runs from top to bottom, especially with a quick program upgrade. The stock Allison cannot even come close to holding it's power.

RJ had dyno runs similar to a stock Dmax, but even adding an exhaust to the Dmax would step it up and away. We'll see how well his new engine runs...

[Govt issue]

So I guess the major difference in the two eng ines that we can't duplicate in the 6.5 is cylinder head design? Cid is almost the same. What is the major difference that causes such a power improvement. maybe some one need to redesign a cylinder head.

[Dvldog 8793]

Howdy
I think structual integrity has something to do with it also. The 6.5 was never intended to put out the same amount of power as the duramax.
Who knows????
L8r
Conley

[Michael McRae]

OK, you can all call me a traitor after reading my e-mail.

Well, I have put 250K+ miles on a 1982 Chevy 6.2 Diesel, and I know own a 1995 6.5 suburban. I was not happy with the GM tranny problems with the 82 model, and now I have learned that the electronic IP models (my 95 suburban) have some serious injector pump problems!

Of course, my suburban is currently not running due to injector pump problems....... and I need a truck right. Well even the used Duramaxes are incredibly expensive, so while having a bad GM taste in my mouth I broke down and bought a 2000 Ford Powerstroke 7.3L.

All I can say is WOW. This baby has all the power I could ever imagine needing. Ford (International Harvester) really seams to have cracked the Diesel nut quite well. Everything seems well thought out, filter placement is excellent, 18 mpg, and so forth. My only complaint is that it is so loud under acceleration. The sound level is OK once my speed levels out. I'll have a better feel for it after I put on some more miles.

Yes I am a happy traitor..... but I plan to keep my 6.5L suburban for a while longer. Of course I have to get the injector pump fixed before I can drive it again.

Mike McRae, 95 Suburban, 95K miles.

[Kennedy]

Just wait till you have to work on something like the turbo...

The 7.3 is a pretty solid unit that will run just shy of 200 RWHP in most cases. Stock Dmax will do around 250 pretty consistently. Just for comparison sake.

[matt-max]

having enjoyed four duramxes (2 LB7 and 2 LLY)as well as numerous carbureted 350's, efi 5.7's (vortec & non), 2 6.0's, 5 6.5td's, and ford 302's, 360's, 390's, 351's and 460's i can objectively say that nothing else i've had pulls anywhere near as well as a duramax.

yes, the LLY is a dog in first gear without any modifications. i met a 5500 LLY tow truck driver who considered it dangerous it was so slow off the line....swears his 6.5td 3500hd wastes it from a stop and in getting a load moving. he agreed that once into second gear, the LLY would 'walk the dog with the best of them' whatever the heck that means.

adding an AFE or S&B intake on the 2004 and 2005 LLY's has made a very noticeable difference in economy as well as first gear perfomance and throttle response through the operating range.

on the 2004, i put the 100k+ mile kennedy 4" system (came off my 2001 and 2003 LB7's and still looks about the same as when new) and the performance improvement is staggering. this truck has never been reflashed and needs no more power with just the intake and exhaust on it...although i will probably still block off the egr at some point....

anyway, there is no way that any of our 6.5's will come even remotely close to accelerating loaded or towing like the duramaxes regardless of any level of modification we have tried.

then figure in the added reliability, braking and handling performance, and overall comfort levels and it's apples and oranges.

[Kennedy]

Originally posted by matt-max:



on the 2004, i put the 100k+ mile kennedy 4" system (came off my 2001 and 2003 LB7's and still looks about the same as when new) and the performance improvement is staggering. this truck has never been reflashed and needs no more power with just the intake and exhaust on it...although i will probably still block off the egr at some point....

http://www.kennedydiesel.com/photogal/images/KD-4-5-Exhaust-HP-and-TQ-pl.gif

http://www.kennedydiesel.com/photogal/pages/4-5exhaust_lly.htm

[matt-max]

thanks john

that dyno graph is a great example of why the area under the curve is more important than the max height along the curve....unless maybe you're dragracing, i suppose.

i must be feeling the near 100#ft and 50+hp increase around 2250rpm, cause the difference in feel is as i said above, staggering. truck feels like it has another 50+hp that's for sure!

may need to order one for the 05 too....gonna try the LB7 downpipe route first.

matt

[JoeyD]

It looks like a 10 rwhp gain and a 15-20ftlb gain. It's hard to tell exactly.
The 2250 rpm #'s look like a shift spike. I doubt the acual power curve bumps up like that.

[rjschoolcraft]

I doubt that it is a shift spike...

The testing that I've witnessed John do and have had him do on my Suburban does not allow shifting. He locks the transmission in direct with the Tech II and does a sweep from about 30 mph to about 75 mph in direct. If converter clutch control is available (BD TorqLoc in my case), then the converter is locked for the duration of the test.

[JoeyD]

If it's not a shift spike then it must be a glitch or something if the dyno run is a stock truck with just exhaust right?

[Bill Voitel]

Hey Mike another Die Hard Chevy fan here...O.K not so much now after GM told me to pi$$ off. same old story here cracked block at 113K miles to dealer compression check yep right rear cylinders (2) down 150 psi and sucking in coolant burning it out exhaust. opened claim with GM they told me Sorry out of warranty....Sold it bought a PSD.... Don't really like the way it rides compaired to the burb but with the Diablo Predatior and exhaust work Wholey $hit. and I got the truck with 32K on it for 26K cash. Just hope it last's longer than it's 100K motor warranty.....More up-dates from the DARK-SIDE to follow :eek: :eek: :eek:

[Kennedy]

Originally posted by Joey D:
If it's not a shift spike then it must be a glitch or something if the dyno run is a stock truck with just exhaust right? That is an excursion that the LLY turbo seems to take the engine on. It will come at different times based on tuning and airflow. It is likely part of the variable turbo geometry and map changing. If you take the stock exhaust run and shift it down a couple hundred RPM you'll see the similarities in the runs...