I just bought an 08 GMC HD with the Dmax last weekend. Its my first diesel. I have experience with them as my friends have them and one owned almost this exact truck. The problem is none of them have ever set them up right. Just good enough. I want everything to be spot on with mine. Currently the truck has a K&N intake but Im looking for a stock setup to replace it with. Is this the right thing to do? I want to run a DSP5 ECM from nick. What exhaust do I need to go with? Will one from an LBZ work? I want to go turbo back with a 5'' as I plan on running the 500+ tune. I know the stock trans wont handle it forever but it will handle it for a while with some common sense and it wont always be run on it. I also plan on doing the EGR block and fuel rail mods from dmaxtuner. Is there anything else I need to do? What are the benefits of adding a fuel pump like the airdog or fast? Also what gauge setup is the best way to monitor everything? I appreciate any and all help and thanks in advance.

Airbox doesn't really matter. Some folks have trouble with K&N type filters and the MAF sensor but I never did on my LLY. Any full exhaust should work fine but some are easier to install and hang better than others(LBZ model is what you need -correct). If you run the 500+ tune you should start saving for the trans.(in a hurry), run a lift pump for sure(probably have to shim the FPRV but I would run a strong lift pump first and see if you get by, I was probably running 425+ on a stock FPRV with Kennedy Twin lp's), do cognito braces and tie rod sleeves for sure(maybe u joints). All kind of guages..........I tend to like the basic guages on the a-pillar personally!

So it wouldnt change anything as far as with my tune or performance wise if I just kept intake and maybe put a dry filter in it? Like the AEM brute force? Is it worth it to just change the drivers side manifold to an aftermarket one with a fitting for a pyro? I have heard they are restrictive compared to the passenger side.

You can bolt on several pieces and see some small gains but for the money.....

A solid tune will give you all the power you need for most bang for the buck. Look into the Diamond Eye quiet down pipe to help cut out exhaust drone.

Dump the KN oil filter, most have found the stock LMM intake to be very worthy with the dry Donaldson.

Add a lift pump for sure. Going with the AirDog or FASS filters will send much cleaner fuel to the injectors that will prolong life.

Start saving for a Trans but if you will run a 60hp tune and not mash the pedal forcing a 5-4 downshift the trans should last longer.
Add a trans-go jr to increase pressure and make things last a little longer.

If only the t-bars were cranked to level look for front end issues to start to present themselves especially running big tires.

Enjoy, but I see about $8k in upgrades and repairs within 2yrs with your currnet setup and stated plans.

Stock intake is plenty good for 500HP easily. A dry filter will have less issues if over oiled K&N filter may cause MAF issues. For exhaust even stock can push out 500HP easily meaning more like stock pipe size minus DPF and DOC. Bigger pipes just provide louder exhaust sound and some drop lower EGTs. As to which any turbo back exhaust kit will work on your truck it can be any of them sold for 2001 to 2007. they all work on the 2001 to 2010 series trucks. Just on the 2007.5 to 2010 there is a hanger bracket not used. A 4" downpipe helps a little more on lower EGTs to. Not a lot but a little. if you plan 500plus which 525HP is about the max for a stock turbo and injector setup. Of course to get to that point and keep the fuel pressure up the addition of a lift pump will be needed to keep the fuel rail full of fuel. Now at that power the Allison is not gonna hold up for to long. Some have have a good long run versus others. Just a gamble there but if you plan the power then you should be prepared for a built Allison long before you actually destroy it. If you cant afford to have it built and built right do not even plan on running high HP tunes. Just a word of caution. It suck to have a expensive toy setting in the drive waiting to find the money to fix it. A trans-go jr will help some but nothing like a built Allison. For gauges thats up to you. Either analog dial gauges or a digital display ones like Edge Insight CS or CTS that plugs into the OBDII port and provides data off the ECM. Add the expandable EGT probe to get the EGT option.

Brian

You might check out the DIY mods to the stock intake.
On mine the AAT lowered about 15 degrees compared from stock.
The IAT use to be 10-15 degrees hotter than the AAT now they are equal.
Several of us did some comparisons over 2 years ago, and found the stock intake mod was just as good as any other aftermarket CAI including the Banks with scoop.
More airflow = cooler egt's
This mod would even help the ones using the stock airfilter.
I have some pics in my photos.

Move to other performance discussion

Thanks for the help. If I had a stock intake i would put it back on but Im probably just gonna leave the K&N intake and add a dry filter. Which fuel system is right for me? Fass 75? 150? Are there different air dog units? Thanks for the info on exhaust. I will look into a diamond eye quiet downpipe. Is there any advantage to running a different exhaust system besides the diamond eye all the way to the rear? I'm really familiar with the front ends and stress of cranked bars. I plan on adding Cognito upper arms and toe rod ends along with pitman and idler supports. Will the transgo jr really help? I've read there is no difference on the 08 Allison? I understand running over 400rwhp will hurt the trans... I don't plan on doing it often I just want it there when I need it.

I don't think you will have to worry about the fuel system since your not going to pour a whole bunch of power. On the TransGo jr everyone swares by it, I found it helped a little, but only by monitoring the trans with my Edge Insight.
The nice thing with the Diamond Eye was the quiet zone front pipe, I would think if you was to put a muffler on another brand they would be pretty close on exhaust sound.
I like the DE down pipe compared to the other brands, mainly because of the heat wrap.
The only set back I can see is the DE is alluminized not SS

What differences did you notice with the insight after the transgo jr was installed? How hard is it to install? Did u do it yourself? I definitely want to add a fuel system but I may not add it right away. Still looking for some direction in that aspect. Do any/all also add filtration? Is there any better way to monitor everything besides the insight? What are some others?

No free lunch with these things ! It's pretty much a small tune, exhaust, maybe trans-go jr. OR full out trans, lift pumps, exhaust, etc. and go for it !!

Playing around with it in my experience .......ends up with a $5k-$6k transmission and a lot of FPRV problems ! That's why my LMMs run stock tunes........been there and done all of that with my LLY!! Kinda nice to go 3 years and never see a CEL light or have a freakin P1093 code fuel limp you !!

With the trans the insight monitors torque converter slippage, input and output.
The insight is easy to install plug in and play, except for the egt`s you have to install a egr probe. With the insight you can monitor up to 7 parameters X 4 pages on the unit which = 28 parameters with one time setting. You can change what you want at anytime on any page. The only better way would be to invest in at least 28 gauges.
I have 4 different parameters on each page X 4 pages which = 16, I can monitor at the flick of the screen.

My only problem on whats going on with the slippage is the shop that installed my TransGo Jr screwed me over big time and put in Dextron III instead of Transynd which is what I asked for and paid for.
He felt it was not that big of a deal. Dumb A$$.
I towed for the first time since the transgo last weekend and had hotter trans temps than usual 217 flat ground 90 degrees outside temps.
Mines never been above 210 towing up a 7 % grade on a 210 degree day.
The slippage was higher in 5th gear compared to before the transgo before it went into lock-up, not using towhaul and not towing.
I got suspecious from this and found out the shop screwed me putting in Dex III

That issue will be taken care of Wed. and not by that shop.
The past 3 yrs I`ve been limited on what I can work on, this really sucks finding someone I can trust.
And that shop I can not trust.

Sounds like the insight is the way to go then. I was just making sure there weren't other similar monitors made by other companies that may be better or newer. I dont plan to go all out with a trans just yet and I will run it on stock trans safe tune most of the time. What are FPRV problems?

Your gonna get a bunch of different opinions but here's what happened to me:

I was running a Predator tuner on 85hp on my LLY. Plenty of guys on this site think that is a tranny safe tune and there is always the guy that ran the 100 tune like he stole it without a problem. My truck ran fine around town but the first time I topped it out at 120mph on the hwy it started shuddering a little. I let off and the next time I punched it in 5th it limped. That was the "first two times" I ever nailed it in 5th gear on the 85 tune. I switched my tune down to 65hp and it lasted about 6 months and started limping regularly. Hence, the transmission build and a mad as hell wife...especially with a truck on less than 25k miles.

The FPRV problems........do a search. Again most people say you can run up to a 100tune without issue but mine started with just a 65hp tune. You have a releif valve on the back of the fuel rail that has a spring in it. I don't know all the technical stuff about rail pressure and fuel drain....but when you fuel limp you get a P1093 code and power is reduced and you can't run over like 1500-2000rpms until you pull over and turn the truck off and back on again. Once you do it one time, it's easier to do it again(and so forth and so on until it starts limping everytime you mash down hard). You can pull the FPRV and take it apart and shim it , but that only worked for me for a year and then it started limping worse than ever. It is very agrevating and the FPRV is a bitch to remove and if you strip it out......you have some problems ! Do a search on P1093 and FPRV's !

I know the 6speeds in the newer trucks are stronger. But slip is slip whether you know it or not.Hard to say how long one will hold up. From what I have looked at.......about 700ft lbs is about the max the stock 6 speed can handle and there are overachievers and underachievers. Seems like the 6 speeds don't "limp mode" but they still slip and damage clutches. Makes me worry about thinking you are getting away with more than you really are !

I don't want to do another tranny so I can promise you my truck will stay stock tuned or maybe run a mild tow tune with 40-70hp and keep the torque around 700 ft lbs or less. But hell, my truck runs descent stock and with the DPF and DOC gone and top speed off........this one stock still runs over 120mph if I want to do it!!

Don't mean to try and talk you out of it but these trucks are expensive, repairs are expensive, and they are way too easy to over tune. If you do your research, you should be able to make your mind up but I am just giving advise from someone who played around with the wrong(underachieving)truck. And it was an expensive lesson !!

Thanks for your input and I understand what your saying. Some people have no problems and some have all the problems. Guess its the difference between the friday builds and the wednesday builds ha. Same situation. I tuned my friends 08 dmax with EFI live when he first got the truck and he ran it on the 500rwhp tune constantly and ran the piss out of it. Eventually it gave way and started to slip and not pull as hard and it would always lose rail pressure. Then he ran the 400 race/smoke tune and it did ok on that till it started to limp and lose rail pressure more and more till the trans almost wouldnt go in drive anymore without turning it on and off several times. Then put it back to stock brought it to the dealer under warranty and they couldnt find anything wrong with it. It still ran normal with a stock tune and you couldnt tell it was hurt. I am just tryin to research everything and do it right the first time and have the truck built right. Except for the trans which will be last on the list, but I will pay attention to my limits until then.

Any idea which airdog or fass I should run? 75? 100? 150?

I don't know about the FASS. I ran Kennedy twins and they were not all that hard to install, ran unbelievably quiet, and I never had an issue. Like I said, replaced my FPRV and ran the twins and never had to shim the stock FPRV running the Predator 100tune(which really dyno's about 140rwhp ). I know you can't overdo it(fuel pressure wise), might as well go for the bigger one and at least you won't have to add any more for a big tune. Unless the cost is way different, I would go with the biggest one. The thing you want to do is get it going before you ever pop the FPRV, if it never 1093's then you may not have to mess with it !