tune on the duramax...

**0rion** · 02-17-2011, 06:21 PM

Loaded a 90HP tune today on the truck and corrected for the larger tires. The speedo still feels like it's off to me but after driving it again tonight I'm not so sure. I'll have to pace my wife's car to see where it's at. Definitely gave the truck more pep. I'm not running a pyro or boost gauge so I want to stay conservative until I get those. Also on the stock tranny so that's a concern.

**HOBS** · 02-17-2011, 09:07 PM

What tuner did you get? Its a mighty slippery slope once you start modding diesels, just cause the power is so easy to get. Have fun!

**chuck75** · 02-18-2011, 03:08 AM

I never understood why the factory didnt put better transmissions in the deisel trucks. there are guys pulling alot of hp out of these thing and the trans is always a problum from the very start. oh well good luck with yours

**konigandy6** · 02-18-2011, 02:44 PM

Do you not have an Allison? Can't get much better than that.

**0rion** · 02-18-2011, 04:56 PM

Originally Posted by HOBS

What tuner did you get? Its a mighty slippery slope once you start modding diesels, just cause the power is so easy to get. Have fun!

just a tune out of the repository on the diesel boards. I'm gonna have to adjust it....shifts like ass. I'll have to log the truck first and get some good logs and see what's going on but I'm not liking the shifts at all.

**0rion** · 02-18-2011, 05:19 PM

hmmmm.....doing some reading. Looks like I got more modding to do.

I think what's going on is the truck is de-fueling and that's why the shifts feel so shitty. Looks like a transgo jr is in my future and probably a lift pump. Or I put the stock tune back in and call it good to go

I already have 1 money pit....don't need another one.

**eacostad** · 02-18-2011, 06:40 PM

are you using efi live to tune your duramax, Ive been running a 150hp tune on mine for 2 years now with stock trans and no problems. You are going to need to add a lift pump and exhaust to run a good tune correctly. Im running an Airdog 150 lift pump, 4" MBRP straight piped exhaust(no cat, no DPF), Efi live tuning on my 2007 ecsb. thats all you need to have one fast a** duramax

**0rion** · 02-18-2011, 08:21 PM

yeah...efilive. I have 4" diamond eye straight piped exhaust on there. Looks like I'll be in the market for a lift pump. Them bastards are pricey!!! If I do that I'll do a trans go jr too. It starts adding up in a hurry. I'll have to decide ultimately what I want to do.

**Tyler_LS1** · 02-18-2011, 08:31 PM

I don't see why you would need a lift pump for a 90hp tune, you should have Rob sen you a tune and try it. I mean a lift pump won't hurt but I've got a couple friends running smaller tunes without a lift pump and they run and shift great. Do you have a DSP switch?

**0rion** · 02-18-2011, 08:43 PM

not yet.....my bumper to bumper just expired so I haven't really done anything to the truck yet. I need to get out and log and see what's going on with the shifts. The 1-2 shift just feels like shit. Feels like it's shifting early (the tach looks like it's close though) and doesn't really shift with authority. It kinda limps into 2nd gear. I gotta log it is all.

**eacostad** · 02-18-2011, 09:01 PM

Originally Posted by Tyler_LS1

I don't see why you would need a lift pump for a 90hp tune, you should have Rob sen you a tune and try it. I mean a lift pump won't hurt but I've got a couple friends running smaller tunes without a lift pump and they run and shift great. Do you have a DSP switch?

I'm running Idaho Robs tunes on a dsp5 switch, the lift pump actually makes a world of a difference, with it you aren't going to run outta fuel at wide open throttle and your truck will shift better because it will eliminate defueling with on your smaller tunes.

**HOBS** · 02-19-2011, 09:48 PM

It shifts funny so you think its de-fueling? I doubt a 90HP tune would drain your rail and if by some oddity it is it would only do it under WOT. Still de-fueling feels different from a bad shift in my experience. Try a different tune lots of people think they're masters at efilive but few are.

**Gama6970** · 02-25-2011, 07:25 PM

Hey listen to eacostad. That truck hauls ass like I've never seen one do.

**0rion** · 02-25-2011, 08:00 PM

my tranny adjusted and is shifting fine now.....took it forever to adjust to the tune. Wonder if you can disable adaptive shift in the tune? I haven't even looked at the tranny side of things yet.

**5.0THIS** · 02-27-2011, 01:00 AM

I thought 50-75hp was the limit on a tune without putting the tranny into limp mode... or did your tune account for that? You could always just throw a 50hp handheld tune into it live with it. those are pretty safe and still add some power.

**HASTINGSRJ** · 02-27-2011, 02:38 AM

you will put the tranny into limp mode if you do boosted launches. On a 90 hp tune he should be fine. I run a 100 hp, tow, economy, stock and hot tune on a stock tranny with no problems. I dont play with the hot tune (200 hp) too much though.

**joejenkinsglass** · 02-27-2011, 04:19 AM

be carefull the stock ally is only rated about 70 hp more than the stock dmax. It is so easy to over power. What we have to remember is when you add a little hp it comes with alot of torque. My old 93 chevy has the drivetrain of a 2008 dmax and its great but your right the shifts are nothing like a gasser. It will defuel between shifts unless tuned out. We need a site like this one for our diesel trucks. Diesel place was alright till lately now they are wanting a subscription f that. Mods we could use a good free place to talk smoke

**pajeff02** · 02-27-2011, 06:08 AM

I don't speak "diesel" -- what's a lift pump?

**Tyler_LS1** · 02-27-2011, 09:16 AM

90hp with the stock 6speed ally is pretty safe, you can always add the transgo jr to help beef it up a tad. what ruins the ally is the High HP tunes on the 4-5-6 shifts. a lift pump is a lower pressure pump (11-12.5 psi) that pumps more volume up to the CP3 (safer and necessary when running bigger tunes) the CP3 pump is the injection pump using higher pressure to feed the injectors some will run Dual CP3s

**FasstChevys** · 03-01-2011, 08:31 AM

Originally Posted by joejenkinsglass

be carefull the stock ally is only rated about 70 hp more than the stock dmax. It is so easy to over power. What we have to remember is when you add a little hp it comes with alot of torque. My old 93 chevy has the drivetrain of a 2008 dmax and its great but your right the shifts are nothing like a gasser. It will defuel between shifts unless tuned out. We need a site like this one for our diesel trucks. Diesel place was alright till lately now they are wanting a subscription f that. Mods we could use a good free place to talk smoke

http://www.duramaxforum.com/

Have you tried this one? It isn't too bad from what I can tell.

I have a Hypertech Powerprogrammer III in mine with the 100 hp 'setting'. No issues as of yet. I think what it has is enough - I don't want to lose the transmission by thinking it's a race car. It gets right around 18 mpg - I'm pretty happy with that.