08 2500 Suburban Questions

900sub6.0 · March 20, 2008

I see the subs listed in the 1/2 ton section but figure I got more in common posting here...

I just ordered a 2008 2500 suburban. The $69.700.00 (CAD) msrp hurts but I needed an 8 pass vehicle that can tow. I also ordered 20x8.5 Weld Cheyenne 8 wheels, Michelin 285/55/20 LTX A/T2 tires and a Magnaflow catback exhaust system. The sad part is that I have to wait 2 months for my sub. Now for the questions. Is anybody running these tires on there sub without any rubbing issues? How is the sub on fuel?

Thanks

ATMINF · March 20, 2008

For the wheels if the backspacing is correct they should be good, but I never put aftermarket rims on my old 2001 Burban so I really can't help. As for fuel milage on my 2001 3/4ton Burban it had a 6.0 gasser and 3.73 rear gears, I got 13-14 city and up to 17+on the highway. The new 3/4tons have the newer 6.0gasser and also the new 6L90 six speed trans so that may help, but I am not sure. One other thing is that the new GMT-900 3/4ton trucks do share alot with the olderGMT800 3/4ton platform so thats why I chimmed in. Hope this helps!

c4racer · March 21, 2008

For the wheels if the backspacing is correct they should be good, but I never put aftermarket rims on my old 2001 Burban so I really can't help. As for fuel milage on my 2001 3/4ton Burban it had a 6.0 gasser and 3.73 rear gears, I got 13-14 city and up to 17+on the highway. The new 3/4tons have the newer 6.0gasser and also the new 6L90 six speed trans so that may help, but I am not sure. One other thing is that the new GMT-900 3/4ton trucks do share alot with the olderGMT800 3/4ton platform so thats why I chimmed in. Hope this helps!

wow - that mpg is pretty good for a 6.0L burb - was it 2wd or 4wd?

And what speed on the hiway?

We used to get 12-13 around town and 15-16 on the highway in a 2001 1500 5.3L with 4.10 gears

My current 01 burb is a 2500 w/ 8.1L / 3.73 and gets 10-11 around town and 13mpg highway doing ~70mph ave.

both were 4x4's btw.

ATMINF · March 21, 2008

It was a 2wd, and my highway speeds were always in the 75 range. I don't know if I am just lucky or it also because of me switching over all the fluids to synthetics. Granted I also know the new trucks have all synthetic in the trans, rear dif. My current ride which is a 2006 2wd 2500HD with 4.10 rear and 4L80 trans gets 12-13 city and 16+ on the hwy, it also has a 89 performance tune.

c4racer · March 23, 2008

It was a 2wd, and my highway speeds were always in the 75 range. I don't know if I am just lucky or it also because of me switching over all the fluids to synthetics. Granted I also know the new trucks have all synthetic in the trans, rear dif. My current ride which is a 2006 2wd 2500HD with 4.10 rear and 4L80 trans gets 12-13 city and 16+ on the hwy, it also has a 89 performance tune.

Pretty impressive for a 2500HD - way better than I've heard other people getting, at least in ext or crew cab models. Congrats!! I think the tune must help quite a bit too - I am thinking I need to get one for my burb - both to improve mpg and also remove some of the TM nanny that GM builds into these things.

I have synthetic in everything but the trans at this point - and a whole pile of Amsoil ready to go in there when I get some time to work on it.

But the burbs are pretty heavy, so that doesn't help. I have one buddy with a 2002 HD2500 stripper LS 6.0 4.10 gears but in a 2wd standard cab, long bed - and that thing gets reasonable mpg too - better than my old 1500 burb, but probably because it is fairly light - no backseat, leather, elec gadgets - just the basics.

ATMINF · March 23, 2008

Yes I remember that my old 2001 Burban weighed about 6200lbs, and my current 2006 Silvy is around the 5600-5700 mark. I don't have the number on me, but got it weighed empty and loaded, when I was taken in some scrap metal (old office desks, and file cabnets, and wall lockers) to our Post scrap metal yard. My truck is also a stripped down LS, roll up windows, maual locks, seats etc. It does have dual AC, CD player, cruise, so I am happy. All in all I can't complain it does well fo a big truck.

pmbss396 · March 25, 2008

I just got a 08 2500 Suburban a few weeks ago, I love it. I got 14mpg last tank, mixed driving 2/3 highway. It is a LS with only a few options. If you are worried about mileage wider tires probably won't help, but they will look cool.

900sub6.0 · March 25, 2008

Thanks for the replies.

What is the "89 performance tune" being mentioned???

pmbss396

How do you like the ride unloaded? Hows the power? Any issues?

pmbss396 · March 25, 2008

It rides great I haven’t loaded it up to see how it rides with a load but I would have to say A+. The wife falls asleep almost before the seat belt is clicked. I think it is fast for the size, with that six speed, first gear is real low and it pulls out of the hole strong. I was pretty surprised how well it moves. It has a pretty deep rumble when you get on it I like it. It isn't my big block chevelle '68, but I am impressed. It's hard to wipe the smile off my face when driving it, well filling the 39 gallon tank turns that smile around. But it is worth it.

900sub6.0 · March 26, 2008

When I test drove the 1/2 ton it felt nice and felt slower than you were actually going. I am a gm automotive tech here in alberta and have been really watching what comes in and for what reasons. Being 75% truck country and oil country. The big oil companys can kill a truck within 2 years so we see the weakest link in the nbs early on. The thing is I haven't been able to personally drive a 3/4 Suburban because the only ones around are rental companies. We are in the process of replacing about 10 more torque convertors and pumps in the allisons (06 and up) we just replaced about 20 allison trannies in the last month and a half due to -40 C weather.

ATMINF · March 26, 2008

The 89 performace tune is about getting the PCM retuned by a aftermarker tuner. When I got my PCM re-tuned I got it done by Charlie Wheatley( gowheatley.com) and he did alot of different stuff for me, so the truck was not bogged down so much by the torque managment, engine management, and changed the shift points/firmness, etc. Do a seach in PCM tunes on this site and you should be able to get alot of info. Or you can always ask and the people on this board you be able to help you out. Basically it really woke the truck up and removed all of the hesitation that these trucks have"built into" them.

pmbss396 · March 27, 2008

Just a note i just got some weather tech front floor liner for the suburban. They fit great and Amozon has a great price. Way cheaper than anywere else.

http://www.amazon.com/WeatherTech-440661-B...1277&sr=1-1

900sub6.0 · March 28, 2008

I just picked up my WeatherTech Floorliners yesterday. 1st, 2nd, 3rd and cargo area. yes they are expensive but look and feel very high quality. My magnaflow exhaust came in today also. The catback is straight through with the 2 into 1 "Y" inside the muffler. The system looks real nice.

I am going nuts waiting fo this burb. I just recently sold my 2005 GMC Crew Cab. Full Alpine Audio/Visual through out.

c4racer · March 29, 2008

Wow - I just ran my first tank of the summer gas in my 8.1L 2500 burb and it returned an amazing 13.4 on a ski trip up above 7K feet with 5 people and a Yakima rocket box on top. Gotta love that!! Best I've seen previously on the winter gas was 13.0 and that was on a flat lander all highway trip doing ~70mph average. In comparison my Audi only gets about 19mpg going to the same mountains and that is on 91 octane, although it might also do better on the summer gas. But no way 5 people and gear for a 3 day ski trip would ever fit in that little thing!!

Funny - my buddy commented that about 20% of the ski area parking lot was comprised of Suburbans..... No wonder why that is - best ski rig made for hauling a whole crew to the mountains. Of course I will take my S4 any time for a blast up with 1 buddy or just me and my two daughters.