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turbo'd 6.2 power

guz71

guz71

1/2 ton status
Joined
Sep 17, 2006
Posts
387
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Location
lubbock/houston
I know beating a dead horse here but I would like to get some feedback from people that DD these motors. Ive heard the turbo 6.2/ tbi 350 comparision a few times, but after reading and hearing about some other experiences, it seems like a turbo'd 6.2 takes the cake.

I read an article where they turbo'd (banks kit) 6.2 in a k5 blazer that was lifted on 35's. They said after the upgrade, the were able to motor up vail pass on I-70 doing 65. Thats a 6% grade I beleive and its over 10000ft up top. I just did that stretch on I-70 and my tbi gave everything it had to pull 35 up that pass. So that really makes me think the 6.2 has a one up on a tbi 350. Know doubt, forced induction really helps out that high but still that would have blown past me and welded my doors shut.

I know even with a turbo, the 6.2 isnt going to be blistering, but I could live with the speed I have now all day. I just need some more umphh on the highway and do better than 12mpg. I have wanted to the swap for a while but the 203 took a dump, so I am getting ready for a doubler.
 
I think the comparison to the healthy TBI 350 is in acceleration. Being able to hold speed on a grade the turbo'd 6.2 should do better as it has a sh1tload more low end torque.

Rene
 
I have a 6.2L turbo K30 Dooley autoamtic with 4.10s in it and a buddy of mine had the same truck but with a 350 (carb'd) and a SM465 with 4.56s. His truck ran very well (about a 300hp build), but I think mine would be the same or a bit better (manual vs automatic might play into this). The big difference is how much easier the 6.2L moves the truck from a stand-still or going down the road. That 350 was laboring to do some of the stuff my truck does quite easily. Running on the highway is definitely easier with the 6.2. Roll on the throttle a bit and go, whereas the 350 was mash it to the floor until your leg twitches and hope you don't have to let off for slower traffic.
Oh, and I haven't been lower than 12mpg in my K30 Dooley that is driven in rush hour traffic to and from work.....
 
Interesting, the acceleration of my tbi 350 is liveable but its working hard to hold 70-75 on flat grade. I basically hold down the throttle just a little bit before the truck wants to shift into 3rd. I have a manual switch on my TC so it hasnt been a problem, but grades kick my arse. 12mpg is what I was getting on the highway cruising 70, the best I have ever done is 13. In town with traffic I dont even want to know what I get, it has got to be in the single digits. After reading many of Rene's and other's experiences, I think a 6.2 would be great for my application.

I want to do it right and go through it with a fine tooth comb so its going to take some saving up. I have pretty much figured out how to solve all the problems with swapping it into a TBI truck( one of my buddies did it on his 88 tbi c10). I also have to switch back to an accessory belt but thats no biggie. With the diesel I take it you have to run hydroboost, I am real close to getting my hydro assist so I dont know how I feel about the hydroboost. I almost want to say he didnt run hydroboost, but I am not positive.
 
BadDog ran hydroboost with hydro assist steering. Might want to pm him because he'll never read this thread...

You pretty much need hydroboost brakes, but they're much better than vac assist.

For great ideas and tech on 6.2 build/freshenup check out MaxPF's 6.2 build. Gear drive, stud girdle, ARP studs throughout, 'J' code, new Fel-Pro head gaskets (metal core I think) as well as the other regular junk like quick heats.

I'd try and find a diesel pick-up or K5 to use as a donor...all the little crap will kill you otherwise. Things like the engine bay wiring harness, rad, rad mounts, shroud, oil cooler lines, GP controller, fuel filter(s), battery trays, cables, throttle cable, TV cable, hydro-boost.

Rene
 
guz71 said:
Interesting, the acceleration of my tbi 350 is liveable but its working hard to hold 70-75 on flat grade. I basically hold down the throttle just a little bit before the truck wants to shift into 3rd. I have a manual switch on my TC so it hasnt been a problem, but grades kick my arse. 12mpg is what I was getting on the highway cruising 70, the best I have ever done is 13. In town with traffic I dont even want to know what I get, it has got to be in the single digits. After reading many of Rene's and other's experiences, I think a 6.2 would be great for my application.

I want to do it right and go through it with a fine tooth comb so its going to take some saving up. I have pretty much figured out how to solve all the problems with swapping it into a TBI truck( one of my buddies did it on his 88 tbi c10). I also have to switch back to an accessory belt but thats no biggie. With the diesel I take it you have to run hydroboost, I am real close to getting my hydro assist so I dont know how I feel about the hydroboost. I almost want to say he didnt run hydroboost, but I am not positive.
Click to expand...


Well I have only been driving it for a couple of months but my suburban 6.2l banks turboed on 33" tires and stock axles ( I believe 3.73 but I need to check) goes fine anywhere I point it, including holding 65 up the grape vines on I5 CA that os a 6% grade, I have the 700R4 and I downshift to 3rd because I don't like to force it with the big tires and stock axles but it stays at 65 fine and I can actually go faster but that is the speed limit :D
I am getting 19-20 MPG depending on how steep grades I drive.
In comparison my 2wd c20 with a 350 has a problem staying at 55 up the same hills and I get 9MPG on the best days, 5 towing a small 5000 lbs load
I love it and would not go back to gas, I am converting all my vehicles to diesel.:bow:
 
Yeah I have ready through MaxPF's build probably 10 times already, truly is an inspiration. Yeah I agree on findin a donor, I can see where the little things would kill me. I am not sure if I want to buy a decent blazer(diesel) and swap my goodies over to it or just buy one with beat up body etc. and swap the goods over to mine. All of my money is in the drive train and suspension so it wouldnt bother me to much to just swap it over. I wouldnt mind losing the bush wacker cut out flares either... My budget will be 4-5K so I think I would go ahead and rebuild the diesel with all the goodies and hold off on the turbo if I have to.

If yall dont mind, after everything was said and done, what did the swap set you back? Like I said I want to rebuild with all the goodies and I think I could do the swap right for under 4K.
 
I grew up on small-block-powered 1/2-tons (1st and 2nd generation). They are fine trucks, but I was always tweaking and tuning and replacing various fluids.

I bought my first diesel 1/2-ton last year, and it has had a Banks turbo on it from day one of my ownership. I am in love. Those damn things just run.

It dawned on me as strange one day when I looked at my sig and none of my (running) trucks has a smallblock in it. Sacreligious?
 
Haha that is funny. I want to cross over to the diesel side bad but being in college and only working full time in the summers, money isnt exactly flowing. I kind of wish I would have addressed the engine before I did the 1 tons and everything else, but its a reliable DD and I can wheel now...just not very gas friendly. I have been doing a ton of research into these old diesels, hopefully by time this summer rolls around I will know as much as Rene and some of the other guys:bow: basically be a database lol
 
Granted mine isn't turbo'd, just a J-code engine, but properly geared for their tires the 6.2L isn't all that bad. I had driven them before in 3.08 geared CUCV Blazers (dogs) and CUCV trucks with 4.56 gears and 31" tires (WAY too deep geared) so I wasn't sure what to expect with mine when I got it last year. With the 4.56 gears and 34"ish HMMWV tires it was much better but still a bit low geared. Now I have the 38's and man, it's great. Not a powerhouse but neither were the ol' SBC's with carbs. 160hp is 160hp but mine has more torque and gets much better gas mileage.

A turbo is a ways off for me but DO THE SWAP! Even if you can't turbo it right away DO THE SWAP first chance you can. Some of the build threads on here and over on The Diesel Page make me wonder how powerful you can make a reliable NA 6.2L.:D
 
guz71 said:
Yeah I have ready through MaxPF's build probably 10 times already, truly is an inspiration. Yeah I agree on findin a donor, I can see where the little things would kill me. I am not sure if I want to buy a decent blazer(diesel) and swap my goodies over to it or just buy one with beat up body etc. and swap the goods over to mine. All of my money is in the drive train and suspension so it wouldnt bother me to much to just swap it over. I wouldnt mind losing the bush wacker cut out flares either... My budget will be 4-5K so I think I would go ahead and rebuild the diesel with all the goodies and hold off on the turbo if I have to.

If yall dont mind, after everything was said and done, what did the swap set you back? Like I said I want to rebuild with all the goodies and I think I could do the swap right for under 4K.
Click to expand...

All told I spent $2K getting the 6.2 into my truck. I bought a motor first and it supposedly came with everthing i needed. The deeper I got the more I realized I still needed, so I bought a running donor. That worked out as I got all the incedental crap I was missing, plus I sold what i didn't need for $100 less than i paid for the running truck.

What made my swap add up quick was the crap that went south right after I got it running. Two batteries, hydroboost pump, alternator, starter, lift pump...and 5 months later injector pump and injectors needed rebuilding. :doah:

Getting a known good runner is a less expensive option IMO...as long as everything is in decent shape. My donor was good for pretty much nothing but some wiring. Pretty much everything else I got off of it went bad within 3 months or less.

Another option if you're patient is looking for a '93 6.5TD donor. They were rated about 190 hp and I think over 400 ft/lbs of tq. 93 was still purely mechanical too and of course you'd have the turbo stuff right away.

Rene
 
Interesting. Since the blazer is my DD and it will be for atleast 3 more years if not more, I want to totally rebuild the motor, unless I find one that is rebuilt of has extremely low miles. It only makes since since I have decent 350 and plenty of time. I think I would go ahead a shell out for a rebuilt IP and injectors. I think I would probably go ahead a replace most of the accesories with new ones. I definately want a higher output alternator, mine voltage drops when my blinker blinks...I have an optima so maybe I will actually be like the commerical where battery outlasts the truck haha. Things i would want from a donor would be like the radiator, wiring, hyrdroboost etc. I wish I could swap my accesories over but being an 89 its a serpentine belt so no such luck there. Id also have to get a new torque converter and governor for the tranny. So I can definately see where things add up.

My buddy that did the swap in his tbi basically left the ECM in there and unhooked the check engine light. I forgot what he used the ecm for but I want to say guages. He swears up and down he ran no hydroboost brakes and it was fine, but I think with the 1 tons and drums I will run the hydroboost for sure. It seems like there has been good results with hydroboost and ram assist too. This was interesting I thought, but he just wired the tbi fuel pump to a ignition source and used that. Hes a mechanical engineer and he just flat out knows his stuff when it comes to automotives and especially offroading, but I think with a donor truck I would swap over the tank and what not.

Thats a good point about the 6.5. I guess they are basically the same block so they weigh about the same. I dont want to loose my alcans up front, yet anyways. To me I think the 6.2 would be a much more simple swap but if the 6.5 is mechanical and same block then it shouldnt be any worse.One factor would be economy, I am guessing the 6.2 still has the upper hand even turbo'd?
 
The stock TBI fuel pump is relatively low pressure, and used in the diesel applicaiton all it does is act as a lift pump to the injector pump, so I don't doubt it works fine.

Not sure how he could get the brakes to work without hydroboost. The stock gas setup would require vacuum from the engine to power the booster...and the diesel does not make any vacuum. A lot of 6.2's came with an vacuum pump (my '90 did) but it was just used for stuff like the cruise control and such, and I didn't think they could supply enough vacuum to properly run a brake booster...but I don't know for sure. Part of my thinking is I don't know why the factory would bother spending the money on a vacuum pump and also the added cost and complexity of the hydroboost brakes on a Blazer???
 
Yeah he had a vacum pump on his. He had a bad leak for the longest time and couldnt ever figure out, finally figured out it was the vacum pump (something with the flap...I am still learning). I talked to him again yesterday and he siad he had zero problems running his brakes like that, but hydroboost doesnt look that complicated so I want to run that. The way my brakes are now, it doesnt push enough fluid so I think the hydroboost would be nice as long as it works fine with ram assist.

Cruise control... I completely forgot about it. Mine doesnt work now and even if it did Im sure the tranny would never stop shifting because the slighest increase in wind or grade slows me down. With the diesel, it should have enough grunt to hold a constant speed under normal circumstances, so I will be looking forward to hooking that up very much. A few weeks ago I drove 13 hours non stop with out cruise control...my leg is still sore.

That also reminds me about my torque converter. If I understand correctly, the TC lock up controls come from the ECM. I would just leave the ECM in there like my buddy but I am thinking with the absence of everything else hooked that its not going to work. I have manual switch that I control the lock up in OD, it is grounded out through the 4th gear pressure switch. All the switch is doing is breaking the hot running to TC, so it might work regaurdless if the ECM is completley hooked up. If not, its just the 3 wires running to it so it would probably be easy to just wire it up seperately.
 
For what it's worth I believe you'll need a diesel torque convertor when you do the swap.
 
Yea Ill have to swap out the torque converter and the governor gear in favor for there diesel counterparts.Definately replace those with new peices. I was just talking about the actual TC lock up controller, didnt think about but the diesel TC's maybe set up different too(as far as lock up goes I mean).
 
Just out of curiosity, what size tires do you have? What gears are in your axles? I think part of the problem is going to be gearing/tire size. You should not be constantly shifting the tranny on nearly flat ground with any motor.
 
A diesel TC isn't any different than a gasser. I've got an HD 1600-stall TC on my rig and it works just fine.
 
There's a difference in the factory transmissions and some other guts. Due to the diesel's lower torque curve.
 
The internals of the transmission are indeed different - I agree. The valve body and governor are set up differently.

The factory TC may (?) have a slightly different stall design, but they are fundamentally the same torque converter (and not much different in stall).
 
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