Max boost W/ I/C, 21:1 compression?

[84 Convert]

I have a lead on an inexpensive '01 Dodge intercooler. If I put a turbo on a 6.2 with that intercooler, what should the boost limit be without going to 18:1 pistons? Eventually I will go there but probably not immediately. Also, are 18;1 pistons less expensive for 6.2 or 6.5 bore size? I believe I saw somewhere one was much more than the other.


Thanks

Gregg

[Dieselboy]

The ready made low compression pistons for the 6.2 are 19:1 from Peninsular and are much less expensive that a set of 18:1 6.5s. IIRC ~$350 vs. $900

[gmctd]

With new orange sticky head gaskets, new intake gaskets, 14psi will effectively double 'seat of the pants' power.

Also is preventive 'coolant leaking from 6.2' maintenance.

Shoot for 7psi, otherwise.

[grape]

On a side note, try to find some 6.5 heads and injection lines. When I cc'd my stock bore 6.2 with the latest 6.5 diamond pre chambers, the CR came out to about 19.7-1. This is with the deck surface and the piston crown not touched from stock, using felpro gaskets. I didn't realize they changed the actuall volume of the chambers, I thought all they changed through the years was the design of the opening.

[TomEichenberger]

"With new orange sticky head gaskets, new intake gaskets, 14psi will effectively double 'seat of the pants' power.

Also is preventive 'coolant leaking from 6.2' maintenance.

Shoot for 7psi, otherwise."

Hey JD,

What's up with "the new orange stickey head gaskets? Would using these new gaskets and high tensile studs reduce the problem of blown head gaskets in high horse power, turboed engines.

Thanks

[gmctd]

Couldn't hurt, Tom. Those rubberized gaskets offer greatly improved sealing over the original 'dry' sandwich-type.

The stock 21.5:1 c.r is considered very high for a Diesel, but helped with cold-starting and other driveability considerations in 1982, before turbocharging was common. As did the indirect injection system.
GM was trying to get gasser drivers to switch to Diesel to comply with C.A.F.E.

The scheme for more power out of the 6.2L series is to lower compression to 18:1, allowing considerable boost increase, up to 18 - 20 psi . John Kennedy was running 18:1 at up to 26psi for testing, in his '96 6.5L hotrod truck, but does not recommend those high boost levels.
Splayed-bolt main caps, studs, and all the goodies. And he sells this stuff, if you need it.

Bill Heath was running 16.7:1 c.r. in a twin-turbo '76 swb drag truck, dyno'd at 582hp @ 4700 and 786 lb-ft at 2650 rpm. Total front wheels lift thru 40mph (pictures, not claim), 11.42 @ 116.34 mph. This was in 1993.

Hi boost is not real good, tho, for a 6.2L daily driver, because distributed forces from the oddly-staggered 5-headbolt per cylinder clamping scheme are not equalized around the cylinders. Six, and even seven, bolts are normal design for Diesels, and can hold the high resultant pressures with higher boost levels.

Studs help, but the bolt pattern is of concern, in my opinion.

Factory stock boost for a 6.5L EFI turbodiesel 21.5cr is ~7psi.
With improvements to exhaust, cooling, and charge-air cooling, it's typically 14psi.

p.s. grape, seems like you're doing something neat with this engine, from some hints I keep seeing.
Any comments, pro or con???

[ 04-20-2004, 09:05 PM: Message edited by: gmctd ]

[84 Convert]

Hmmm, very interesting. I may end up not getting the I/C , but instead a '93 6.5TD with one bad head, are the pre-chambers the only difference between the 6.5 and 6.2 heads? I have 4 6.2 heads to choose from. I haven't been able to check for cracks on any of them. Otherwise, I may just have to find a good 6.5 head.

GMCTD: How did the turbo fit with a/c in your truck? I'll check your photos to see what I can. This motor will probably replace the 454 in the k2500 because of the tall gearing, it needs more power to be driveable.


Thanks for the info!
Gregg

[gmctd]

First pop the pan, wipe the three center mains down along the machined block webbing and oil pan rails.
Look for cracks in the machined webbing between each main cap and the oil pan rails.

'90 - up heads had vertical injector angles for factory turbo manifold clearance - the '92-up turbo pre-cups were the only difference, iirc.

Pop the cups outta the bad head, put them in the '90-up 6.2 heads.
Pre-cup cracks are normal, long as they do not span from inner chamber edge to outside edge.

Use the 6.5L injectors.

Get the orange Fel-Pro head gaskets.
The same orange intake gaskets from GM are 92 bucks.
I prefer the Detroit Gasket dry versions, as they do not stick to the block or manifold, allowing for later R&R. And, at only 26 bucks!

And don't forget - this ain't a Chevy small block - parts are expensive, compared to.

Always be sitting down when asking about prices! ;)

[CleviteKid]

JD has a very clever, but somewhat complex, modification that allows him to run the 6.5LTD turbo setup and retain A/C in his "rounded line" body style truck. But he is shy and modest, so you need to ask him very politely, with the most respect and humility, over and over, and then he MIGHT be willing to share the secret design with you. But then again, maybe I just caught him in a good mood one day. ;)

Dr. Lee :cool:

[big swifty]

Although I should probably put this in the classifieds....
I have an extremely low mileage set of late model 6.5 heads that never made it onto my truck that I would gladly let go of.

[gmctd]

Hey...I resemble that remark, Dr Lee! ;)

I just figgered a picture is worth a thousand words. :cool:

But, for those thousand words on the subject, check TBO's fuel filter post in Dr. Lee's 'Ask Dr. Lee' column.*

Has all the gruesome details.

* Sorry - I'd post the link, but along with being shy and retiring (in two years, no less!), I also don't know how to work these new-fangled computers, with all their user-friendly functions!

Fix'em, jes' cain't use'em.... :confused:

[grape]

Well in theory my truck will run great...all the 300 horse injectors and pump stuff, but we will see. The inlet wheel and housing I chose delivers 300hp worth of air at only 9 pounds at about 72% effeciancy, but at 12 pounds it is in the 76% effeciancy range. So on an 80 degree day my actuall temperature rise is only about 80 degrees at 12 pounds, moving 37.5 pounds per minute of air. Therefore the compressed air should be around 160, then it goes through the powerstroke intercooler I got for free. Along with a serpentine set up I snagged out of a wrecking yard for $150. Even got the high pressure p/s hydraboost line and it works on my '82 truck without cutting. All this for my truck I haven't been able to drive since early Feb, but the long block is done so I should be back in the old K5 everday for work in about 2 weeks. Still wish I had time to figure out how to post pics.

[JeepSJ]

GMCTD - Ahhhh. Very interesting solution. I am running into the same problem with my Jeep. The housing looks identical to a GM unit (probably is - most parts on this thing are either Ford or GM). I had looked at installing a complete under-dash system from Vintage Air so that I could remove the box under the hood, but I like your solution.

[gmctd]

One man's answer to the perennial question -

"Make up your mind, Vern. What's it gonna be - turbo or air conditioner?"

First, you must needs repair to a local boneyard of choice.

Therein, amongst the varied and sundry goodies and playpurtys, should you espy an S10\S15 vehicle, '88 to '94 vintage, check out the A\C evaporator housing.

Of similar evaporator size and nearly correct angle to clear the turbine housing, a certain amount of grafting will be required, via pop-rivets and black hi-temp RTV, in re-angling the entire housing.
It mounts in the original location on the firewall.

Results are barely discernable, even to the inquiring eye.

The C\K trucks were equipped with molded epoxy\ fiberglass housings thru the first years, then a switch to molded thermoplastic housings in later ('86 up) years.

S-10\S-15 housings were also molded from those same materials.

I used the molded epoxy\fiberglass versions.

Close proximity to the 600deg (avg) turbine housing will require some manner of foil-over- fiberglass R-12 insulation.

Otherwise, the R-134 converted A\C system performs flawlessly.

And, it was buried in the fuel pumps post, not filters......

[ 04-21-2004, 06:17 PM: Message edited by: gmctd ]

[84 Convert]

Ahah! So it WAS you that used the S-10 stuff! I thought I remembered seeing that somewhere, but couldn't place it. I sure couldn't easily pick it out in the pics... I'll have to go have another look.
Now if I could just come up with the dough for the Brownie thats in the paper, I might just make JD think I'm copying all his good ideas! Ah well, maybe another will pop up later.

Once again, thanks much for the good info.

Gregg

[JeepSJ]

Also - good information about the "sticky orange" gaskets. I would have gone with the good old permatorque blue gaskets. Are the sticky orange made by Felpro?

Arrg - the S10 a/c unit idea may not work for me. My big under the hood box is heater only (heater, fan, ducting). All of my a/c stuff is under the dash with its own fan and ducting. If I did pull all this factory junk out, I would have plenty of room under the dash for a Vintage Air unit, plus it would give me lots of room under the hood for a dual battery setup, plus maybe even enough room for a water tank for an air/water intercooler.

[gmctd]

I think they are Fel-Pro, and may be the same stuff as permatorque blue, but GM uses the orange.

Probably all NASA spin-off stuff.

The 'economy' gaskets are same old stuff I've used since the '50s.

Gregg, there are more installation tidbits about my truck, spread about in the three main forums, here. Do a search by subject, or my member number.
May help fill in a gap or two with yours.
Or, just ask.

Glad to help, folks.

[JeepSJ]

Do I have to go to GM for the sticky orange, or can I get them through my local Felpro dealer?

[gmctd]

IIRC, mine came from GM, but also seems like Fel-Pro was stamped into the steel, along with a part number or two.
I suggest checking them both out for comparison.

[gmctd]

Memory reflash - the orange head gaskets are not Fel-Pro brand - my apologies for any inconvenience(s).
Musta been that all the parts were put in a large Fel-Pro box for 'carrying convenience'.

I'm R&R'ing the heads on my engine, and Fel-Pro is the first brand I checked - gray with blue stripes.

On to GM, or Detroit Gaskets....

[mdapperdan]

I have gained alot of useful information reading this tread. Only a feww word's I did not understand?
thanks Dan

[84 C2B2]

I'm getting all of the stuff needed for a rebuild on my 6.2. Any lead on the part numbers for the orange sticky gaskets?

Jerry