Suburban Conversion and first post

[CumminsBurban]

Hello all! I have reviewed this board for a long time and just yesterday finally spent the money so I could post. I have seen several things I would like to respond to but never have been able. Now I can.



I have a 1996 GMC Suburban 1500 that I put a 12Valve in last spring. I will give more details on it later but I wanted to at least put a post here quickly and let you know I have done it and love it.



I am at my office right now and I have several things to do but hopefully, I will get a chance to post some pics and some stories of the conversion within a couple of days.



Shane Gardner

Indiana

 

[truckstom]

Oh yeah we gotta have pics... lots of 'em... and welcome to the board.

 

[CumminsBurban]

First, I have no pics yet. I will try to get some over the weekend but here is what I've got.



I put a 12Valve with 150,000 in my 1996 Suburban. I used a '93 dodge radiator, and intercooler. I used the 47rh transmission with the triple lock TQ from Goerend Brothers. I used the original transfer case. I had to put a 3" body lift on so that I could get the transfer case between the body and support beam for the torsion bars. I had my driveshafts custom made and my rear one is only slightly longer than my front one now. I used the dodge alternator and the gm a/c. We had to make a mounting bracket for that. I think that looks pretty slick. I have Autometer gauges installed on the pillar. I'm using a Dodge intake system. I pretty well have everything working now except my tach.



My brother, father and I did the conversion. We started January 2, 2004 and I drove it for the first time in March '04 and we spent every weekend on it. I actually felt like it was close to being completed sometime in April '04. Like many projects, it is still not done but once it got driveable I kind of relaxed since my Dad's shop is 100 miles away. I am pushing 40 lbs of boost and have had the egt over 1700 degrees. It was still climbing. My suburban will not spin but it launches.



I have broken the input shaft in the transmission and Dave Goerend replaced it completely. I don't know how much I'm aloud to say here so if I say too much, please let me know, but Dave has been absolutely awesome to work with. He is over 500 miles away from me but we have worked well together and when I had problems, I was completely honest and told him things I had done and he still warrantied his work. Now, I had not done things to intentionally harm the transmission but I am an aggressive driver.



Right now, I shift into lockup and overdrive with two switches mounted on my dash. That works pretty well. My a/c unit runs all the time right now also. I have the pressure switches bypassed because the gm computer does not see an engine signal. I'm hoping to get that all straightened out this fall.



Here are some numbers. I had a 350 and was getting 11. 5 mpg. I got 6. 5 mpg pulling my 24' camper to PA.



After the conversion, I am getting 15 mpg and 11 mpg pulling the same camper. I now have a 37' camper that I pull and I get about 9 - 10 with it and I have an injector messing up. I do have 300 hp injectors and I think one is bad. I have a dead miss at idle but at full throttle you can't tell it. Well, there are so many things to say about this conversion, I don't know where to end so I guess I will say more if there are questions.



One last statement: This is our main transportation so of course, my wife gets to drive it during the day, and I drive our little Rodeo and my Honda Valkyrie to work. I only drive the Burb in the evenings and weekends. I told her I would try to buy her a brand new suburban and I get that one. The response: well, I'm still driving my bike and theRodeo and she still has her Cummins. She loves to make it smoke.



If I could do one thing only differently, I would have put 4" exhaust from day one. I currently only have 3" exhaust and now have to spend more money to get the 4" on.



Shane

 

[FordCummins]

1700?? :--)

 

[truckstom]

To do a swap like that in that short of time, and mostly on week-ends is awesome.

Where do you have the EGT probe? Before or after the turbo?

 

[CumminsBurban]

It is pre-turbo. One reason for the high temp is my 3" exhaust. I am expecting it to drop considerably when I get my 4" exhaust on. Another reason is I have my fuel plate ground and moved forward as far as it will go.



Shane

 

[rhedelius]

I have been contemplating this exact swap! I have a 98 Suburban K1500 and the 5. 7 just doesn't have the torque that I'd like to move all that weight. I love my father's 01 Ram 2500 with the cummins and wished my 'burb had that long torque band that comes on early. I'd love to see pics of your setup.



also, is the rear axle beefy enough to handle the power?

any changes to the front suspension? or is the IFS in the 1500 series strong enough for the weight of the motor?



I've also thought about putting in a ch*vy 383 when my engine goes since the swap would be less expensive, but I would really love the diesel. The 5. 7 in there now is still going strong, but at 179K I know the time is coming when I'll have to make a decision, engine swap or new truck... . (that mega cab is looking real nice).



Rick

 

[CumminsBurban]

Once I figure out how to post the pics, they will be here. I have not done anything to the rear axle. I did have to put a new rear end in because the limited slip busted. I now have an Eaton Posi Locker that still allows it to slip in turns. I love it. Can't tell any difference from stock.



As for the front suspension, I did nothing. I think the truck actually set a little higher with the Cummins and I think it is because it sits farther back than the 5. 7 so some of the weight is on the rear. I did tighten the torsion bars the last time I had it on the lift. I may tighten them a little more but it rides the same now as it did with the 5. 7 My 5. 7 only had 86,000 when I pulled it and there was nothing wrong. Just got back from vac. with a 37' camper and got 10 mpg running 70 and 75 mph.



Shane

 

[CumminsBurban]

First pics

Wow, some on here have some really nice professional looking conversions. I would not say that is the case with mine yet because it is not finished, but it runs and so we're taking a break from the work.



Here are the first pics if this works.



Shane

 

[CumminsBurban]

Try again

Ok, we'll try this again. My pics are too large, but I have put them in the reader's rigs so if I can't get this to work, you can see them there.





Shane





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[CumminsBurban]

Another

Here are some more.



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[CumminsBurban]

And for the rest

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Hope they come through ok. I have a good camera and a cheap camera. I took these with my cheap camera. I hope they are ok.



Shane

 

[rhedelius]

that looks pretty good, thanks for the pics! I figured the rear axle could take a bit more power, I was a little more concerned with the IFS front, but it sounds like it should be ok. My buddy seems to think the IFS front ends are mostly the same on the 1500 and 2500 GM trucks other than a few parts, but I would like more confirmation from someone who knows about that.



Did you use any specific engine mounts to make it work? I noticed you had to fabricate a few brakets for AC and Alt.



Some claim a body lift is needed for the motor itself and I was hoping a cowl hood would solve that, but you put a dodge transmission in and had to raise it to clear everything? The reason I ask is my wife isn't too keen on lifted trucks, up to maybe a 4" lift might be ok, but any higher than that and she loses interest. This is our main family vehicle and with 3 kids, I'd have to get it done quick.



I love the vehicle, it fits our needs and it's paid for so I would just be paying for the conversion itself (which could be around $10K). The next option would be a diesel Excursion. I have to weigh all the options and make a decsion I guess. I wish I had a place and skill to pull it off, in my case it may be better to have it done by someone who's done it before.



Rick

 

[CumminsBurban]

Rick,



I also believe the IFS is the same. I bought brackets from some guy out west. I forget his name but I will get it. We used 5. 7 gas mounts. The transfer case and the IFS is why we put the lift on. We actually had the engine in without the lift, but the transfer case sits right over top of the torsion bar support mount, so there was not enough room between the mount and the body without the lift. I put a 4" lift on and it works well. I did also have to beat in the underside of the body slightly where the transfer case would hit when I would get on it hard but you can't tell it from inside.



Feel free to call me anytime if you want to discuss in more detail.



Shane

 

[rhedelius]

Shane, it looks great! When I get closer I just may have to contact you. I would love a Cummins with an Alison in my burb, but I need to make sure it will all fit.



Rick

 

[CumminsBurban]

Rick,



It will definitely fit. Why would you want the Allison? There are parts of it I think would be good but the 47RH is mostly non-electric so it is an easier conversion. I have a friend who has the Allison and he loves it. I just don't know that it would be worth the hassle to get the adaptar plate and all that to make it work behind the Cummins.



Shane

 

[rhedelius]

I just think that would be the ultimate setup (IMHO). A while back there was someone on here that was putting the Allison in a 98 Dodge 2500/diesel. On another site someone put a Duramax/Allison in an early 90's GM truck (1500). I figured that maybe a Cummins with an Allison would work in a 90's GM truck/SUV. Would definitely be a neat setup. (oh to have deep pockets to go along with the imagination... . )



Rick