72' Blazer with 6.5 and Twin Turbos

[Uncle Wally]

Hi all,

The project has started!

As the title says, this is what the goal is. For those that aren't familiar, I started a thread in Dr. Lee's forum a while back, asking questions about the feasablility of a twin turbo 6.5.

Well, I've done a fair amount of research, a truck has made it into the driveway and I have several pieces of the puzzle.

Goal:
Twin Turbo 6.5 in a classic Blazer.

Look:
It has to look close to original as I really like that classic look. I am very particular about things looking professionally done and working as intended. I also enjoy many of the modern convienences of today, so upgrades will be made. Color choice has already been made: hugger orange and white, with a white top. Black interior. Factory dash with modified gauges to include speed, tach, fuel, oil press and temp, coolant temp, EGT and boost. (I still have to figure out how to get all that in the factory dash bezel, along with making the tach work correctly). Seats will be more modern as comfort is extremely important as is 5 pt safety restraints. A full cage is also in order as this is a full convertable truck to start (seatbelts wouldn't do much good if you went upside down with the top off).

Drivetrain: Dana 60 front, Dana 70 rear, SM465 Trans w/ NP205 case. 35" mudders with a 4" lift kit.

Engine: New design GEP block, stud girdle, extra capacity pan, 18:1 pistons, coatings on many internals, porting/polishing of heads, custom intake, hand fabbed exhaust headers, mechanical IP, custom aluminum valve covers.... and the list goes on and on and on.

Issues I still need to resolve:

Turbos - I still need to solidify which turbos to run for desired power level and turbo lag.

Cooling system - The goal here is 450 horsies

***NOTE - This is the goal!***

It may not be reasonable to attain this with current cooling capacity mods. I am looking at finding a cracked block that I can do some mods to to see what it would take to increase cooling flow. More on that when I get to it.

I'll keep updating this as the project progresses. I already have the trans and t-case in the barn awaiting a thorough going through. The frame should be ready to send to the blaster soon for a cleanup and coating.

Waldo

[GMCHORSHAM]

Uncle Wally,
Sounds like a great challenge that you have set yourself. Can't wait for the updates to commence.
I will include this in my top must view list, along with MPs'- D'Max Diesel power project.
Thank you for the opportunity, to share such an exciting project.
Good luck and smooth sailing.
Rod.

[G. Gearloose]

Sounds like a solid plan, like the driveline. except for the horsepower..
Are the twin turbos just for bling-bling?
I didn't see intercoolers in the list, and thats a lot to stuff in there.

[AndyL]

Wally

I am always a supporter of carfull engineering, but 450 HP is not a reliable expectation from a 6.5. Pennsular said the only reason they made it to 400 HP was becasue they had the entire lake full of water to cool it with. At 450 HP that would put torque at somewhere in the 800 range, your SM465 wouldn't hold. If 450 is your goal, pick up one of those D-Max/ZF6 combos on Ebay for $4000 to $5000.

[Peter J. Bierman]

I would not worry so much for the cooling as long as you use the normal upgrades.
Big differance with a boat is that on the water you can use your 400 horses all the time.
With a truck you use the horses only on acceleration or when towing a heavy load.

I use the stock waterpump, the biggest radiator I could find and a home improvement fan.
I have trouble to keep the engine at operating temp when I drive the truck at normal conditions. :D

Intercoolers are a must however, and help to keep things cool.

Good luck with the project.

Peter

[Dezman125]

Uncle Wally
Next time you are on the net,check out www.justdashs.com (http://www.justdashs.com) ,i think. They have a new dash for the 67-72 body style,they have one that has three small gauge pods moulded into the top dash cover.Nice looking,will use one on my next classic project.

[moondoggie]

Good Day!

How do you feel about folks coming to visit periodically to see what you're up to? I (& a few others) don't live that far from you. I live in Spring Lake Park (Blaine/Mounds View/Anoka area); I've seen posts by others in the metro area too.

If you don't mind such company, let us know clearly when, etc. we might visit, as you would be doing those that might be interested in seeing your project a GREAT favor, & I'd prefer to visit completely on your terms. smile.gif

Blessings!

Brian Johnson, #5044

[Beedee]

Good luck Uncle Wally!!!
Can't wait to see the pics. :D
Keep us posted
Brian

[grape]

turbo sizing isn't an issue. You are doubling the power output of a standard 6.5......so two 6.5 turbo's, one on each bank should be equally matched to 400hp as 200hp is to one gm-whatever turbo.

[AndyL]

Originally posted by grape:
turbo sizing isn't an issue. You are doubling the power output of a standard 6.5......so two 6.5 turbo's, one on each bank should be equally matched to 400hp as 200hp is to one gm-whatever turbo. This isn't correct (no offense). To reach the 450 HP goal you will need close to 30 PSI of boost, any of the GM? turbos are only efficient to about 14 PSI. With GM? turbos you will have more than enough volume, just not enough pressure.

[ 04-14-2004, 03:06 AM: Message edited by: AndyL ]

[Peter J. Bierman]

Have a look at my garett setup.
I run 17 PSI for the moment but thats the limit I set the wastegates on.
More should not be a problem.
I have boost at low RPM and hardly any turbo lag at all.

Hope this helps.

Peter

[bio-diesel]

Peter which garett turbo are you running?

[Uncle Wally]

Thanks for the encouragement. I might need it when things start moving more slowly.

With the 450 horse goal, I figured about 30 psi boost. I might be a touch shy, but we'll see.

'bling bling' ????

I have no idea what that means. I guess I need to get off the farm more often!

I orignally thought I would just stuff an old fat block inbetween the fenders and have a toy to play with. But then every single one of these I see has a hopped up gasser in it. Anyone can mod one of those with off the shelf parts into something respectable. Since I have a propensity to want something other than a 'belly button' vehicle, I thought the diesel idea was kinda neat. Then the wheels in my head really started rollin!

The twin turbo idea started from some thoughts about how the big turbo on my '94 truck performed. I was tickled to death with the oomph it had once you got it rolling. But driving around town, it's pretty much a dog. Unless you power break it a touch to spool things up. At any rate, a 4x4 Blazer with 35's won't do much towing. So I want as much bottom end as I can get. With one large turbo, there's too much lag. But if you used two smaller ones, spool up time would be minimal and there would be gobbs of bottom end. The whole trick is to balance the size so I still get a respectable top end. The drawback with a SM465 trans is the 1:1 final drive ratio. I looked into NV4500's and they are more than 5 times what I paid for the old SM. I'll try that one and see what happens. There is also the issue of trying to convert the clutch over to hydraulic with the NV unit. Everything is already there for the SM unit.

Intercooler? Of coarse. There's no way I'd get that much power without one. I have sat down with a photo of the engine bay and tried to figure out where I would runs tubes and place the core. I will need to get some body panels on before I can really start finalizing any of that. But I have ideas.

Visits to see the progress? I don't have an issue with that. Just give me some time to get things straightened up in my barn. I need to finish putting the trans in my '94 and then clip/shoot a Trans Am and turn that around before I can really concentrate on spending all my spare time on the Blazer. I am still digging up the axles at this point and want to have a rolling chassis before winter. Anyone have any?!! :D

At any rate - there's alot that goes into designing something like this before alot of wrenching gets done. That's where I'm at now!

Thanks for the enthusiasm,
Waldo

Moondoggie - my email is BBARCRANCH at LL dot NET

[ 04-14-2004, 06:45 PM: Message edited by: Uncle Wally ]

[G. Gearloose]

bling-bling = wow factor, not necessarily functional.

I think you can attribute your 94's lackluster off-idle to the ecm, not the turbo.

A fully mechanical injected, wastegated, matched-injector system can really bark from off idle; just ask britannic. My K5 is not nearly as optimized aas his cucv, but its fun to watch the front end get light when I punch it from a stop.

[Peter J. Bierman]

Bio diesel,

I use Garrett M27- A/R 51 's couse I had them lying around, after two years off service I find them performing very good.
I Run 17 psi wastegate setting for the moment but with the 300 HP peninsular pump it seems to be not enough.
I recently blew a head gasket couse of bad timing and some other minor reasons. :(
When I am done repairing the damage I continue research and go to higher boost pressure.
Had to wait for some testing equipment, couse I kinda want to know what I am doing.
I have some tricks up my sleeve I want to investigate as soon as the truck is on the road again.

For a detailed discription off the engine and surrounding equipment read the boost on a budget story in the members area.

Peter

[C.K. Piquup]

If you`re spending all that dough,you might want to talk to Peninsular about their twin turbo set-up($3000).Why not supercharge?The SM465 can certainly handle the hp you are talking.I`d think if it gets to be too much to achieve,you`d be happy with a 300hp motor and a built TH350 or TH400 in that lil`Blazer.I had a`71 w/37"Swampers and a 300hp 350 and it was a gas(to drive,I mean).It had a Hurst"His`n`Hers floor shifter which allowed snappy(and safe)manipulation of power.Consider a soft top,too.You can ride"surrey-style"to keep the sun off,then roll the sides down when you want to get messy.Enjoy,CK.

[grape]

450 hp takes 56.25 pounds of air per minute on a diesel engine. At a 2.0 pressure ratio a 62-1 wheel will move 55 pounds in 70% efficiency range. Thats 815 cfm at the mouth of the compressor. THIS IS ALL AT 14 POUNDS OF BOOST, with ONE turbo. It can be done with the right stuff. The crappy banks inlet wheel will move enough air at just shy of 12 pounds to make 300 hp in the 72% efficiency range. These formulas are all available, trial and error costs too much when your messing with turbos. Do it right the first time with the right components.