Well about a year ago i bought my wife a new minivan so I inherited the suburban. It wasn't long until it had 35 inch tires and a tuner, but it wasn't quite enough so I started this endless project. It now sports a cognito leveling kit, 11.5 inch aam rear end out of a 2005 duramax, a texas speed 408 lq9 with FAST LSXRt intake manifold, a TCI 4l80e, PSC hydro-assist steering, and much more. Here's some pics so you don't get bored and i'll get into details in a bit.

This is how my suburban sat for WAY too long while we got everything installed:


First we pulled the rear weak 9.5 inch ring gear semi-float axle.


got the duramax 11.5 inch ring gear axle all cleaned up, threw on a mag-hytec cover, new brakes, and 5.13 gears.






ordered a 4l80e first from Performabuilt (HORRIBLE HORRIBLE, more on that later) which was eventually replaced by a 4l80e from TCI


Got my 408 stroker lq9 from texas speed and dressed it up, FAST LSXRT 102 intake, etc


painted everything and got it lined up


pulled the old clanky rattly 6.0


which left a nice big hole:


last time i'll ever see this beautiful chevy orange paint job...


oh yeah i got an aluminum driveshaft for the rear since i had to change it for the new axle anyways



just FYI if you use a FAST lsxrt intake, you HAVE TO USE a fast bigmouth throttle body. I first ordered a nick williams, but it didn't fit, there was about a quarter inch of intake manifold sticking out below it. So I ordered the fast bigmouth 92mm throttle body and it came in a fancy case:


More of the intake manifold:


just another fyi, the FAST fuel rail conversion kit does NOT fit the lsxrt, so we put together our own


got the exhaust all welded up with v band clamps:


ready to roll

 

So I ordered a $3800 performabuilt 4l80e. I had wanted Jakes, but there was a 6 week wait and Alan from performabuilt told me he could have his to me in a week. Well, 3 weeks later it finally showed up. It was nasty, with bubbling peeling spray paint on it, so we cleaned it up and painted it POR 15 chevy orange. Then we waited for the torque converter which showed up from FTI, but it was the wrong one. IT was an old rusty th350 converter with dirt and crap inside. When I finally convinced them they sent the wrong one they sent a big beautiful billet cover 2200 stall converter. Well after getting it all put in, the shifts were firm, except for 3-4 shift which was back-breaking/jarring. We pulled the pan off after 200 miles to discover a TON of metal on the plug. After a week of back and forth with Alan/Frank from performabuilt, (during which Frank admitted to not knowing which length springs go where) I send the thing back. To their credit i got a refund as well as a check for taking it back out. After all that I went with a TCI 4l80e which has not cause any problems as all so far.

 

So I have a love/hate relationship with this FAST LSXRt intake manifold. It looks GORGEOUS. It works GREAT, on the high end. But there is a serious lack of low end pull, and it has been a major pain in the rear to get it together. First off, it turns out that although it is a truck-specific manifold, truck injectors don't fit. I had to order a set of ls2 injectors. Second, they produce and make a fuel line conversion kit to get stock fuel lines to plumb into the FAST billet rails. Well, that doesn't even come close to fitting the LSXRt manifold. Stainless lines were way too short. We ended up putting together our own setup and ran stainless lines down to the tank. The last complaint was that i was pretty much stuck with using the FAST bigmouth throttle body since the nick williams 92mm i had wanted to use didn't fit the intake.
OTher than those small issues it has been great. Easy to drill open the ports i wanted, and leave the others blocked.

My real problem with it is that its beauty is hidden under all the wiring in the engine bay

 

I cant see the pics (at work), but it sounds like a great project! I had a similar trans experience with them but not quite as bad. The 9.5 rear is not weak at all, but is a good 150lbs lighter than the 11" unit.

 

weird my old performabuilt lev2 60E was a great trans kicked the **** out of it never talked back once guess there getting to big for there own good to bad

 

Awesome build, looks great.

How do you like the big beautiful billet cover 2200 FTI stall converter?

 

unfortunately the FTI converter went back with the performabuilt trans. Put in a TCI converter with the TCI trans so I don't void the warranty...but it's a not-as-big, but still kind of pretty, billet cover converter.

 

Well, now I am having issues getting my FAST lsxrt intake and throttle body tuned. It will not idle on cold starts. I have to hold the rpms at about 2000 for 30+ seconds and then it will idle and drive perfectly, otherwise it just dies. any thoughts?

 

it surges a lot too right on start up. instead of going to high idle and sitting for a bit til it warms up, it wants to bump up and down 500 or so rpms repeatedly. Again, as long as i hold it for 30 seconds or so then let off slowly i am fine, but anything else and it surges and stalls.

 

sorry one last symptom. It hangs up when i let of the accelerator while cruising down the highway, almost a cruise control effect.