more power ... when is it too much?

[doncannon]

Hello All,
I have a 6.2 turbo(15 lbs), 4911 pump, 6.5 injectors and no muffler. I am looking for more power or am I a little crazy? (hehehe) what also concerns me is that something may break :eek: (the wife and checkbook would not like that). I have an intercooler and was contemplating purchasing a propane injection system or is that pushing the envelope to much (if there is such a thing). I hope you all had a Good Christmas and healthy and safe New Year !!! Thank you all again for the help in advance, Don Cannon

[john8662]

I vote INTERCOOLER!!!

At 15lbs, your just slighly passed the recommended boost w/o an intercooler, I think the general rule is 12psi w/o.

You still have some room for improvement tho.

How far turned up is the 4911? Is the pump basically setup for 6.5 turbo specifications or a 'lil more? IIRC the pump is capable of a little more. Are you getting black smoke when the boost is up? If hardly any smoke, then you can probably turn up the juice a little more.

Ok, Ok, I'll stop, you PROBABLY should not go any further on the more fuel (whether it be Diesel or Pane), but instead see how the Intercooler helps.

My first suggestion would be to find an Air Intake Temp gauge, and install it after the turbo, and see how HOT your charge air is getting. That will surely help make your decision.

Have a Happy new year yourself! I'm LOOKING forward to a fresh start, 2005 took a HUGE chunk out of my hide, don't wanna look back...

[4x4Dreamer]

more power ... when is it too much? Is that really a question a man should ask? :D

I would think an intercooler would be a prereq to propane. ;)

[CleviteKid]

Before you go much farther, you want to be sure your block does not have cracks around the main bearing saddles. You can pull the pan, wipe down the block near the saddles with lint-free rags, then wait about an hour to see if black oil weeps out of any cracks onto your nice clean surfaces. If yes, lighten up your right foot.

If no, intercooler and propane are clearly indicated, and the doctor prescribes same!

Dr. Lee :cool:

[Robyn]

HE HE HE HE
Well I have been around the little GM disels since they came out back in 82
I have seen all the go fast/more grunt goodies installed and a few that should not have been.
I have seen a pile of 6.2 Burnt toast too.
I really think that you are a tad past safe now.
If you are that hard up for power try a 3208T cat. I did one of these swaps back in the early 80's into a GM one ton and it was a terror.
Enough on that.
The 6.2/6.5 will only take so much before they go away. I think you should just be happy with what you have and go for good reliability at this point. More boost is not going to do anything unless you go with a good air to air aftercooler and then the thermodynamic stress on the engine is far more than it was ever designed to stand.
Believe me the 6.2 will put out some real power the question is just HOW LONG before it turns into a cinder.
Got to love em 6.2's
Robyn

[grape]

I've done the math before but nobody listens..............with a 1.84 intake valve and BRAND NEW valve springs at 15 pounds of boost you have less than 20 pounds of seat pressure holding the intake valve shut...........which with a heavy hydraulic lifter at 2500 rpm your camshaft isn't doing what it's supposed to do anymore.

Other than that, the limiting factor as to how much air you can get through an engine is primarily related to the camshaft........so everybody's making the same power because, you guessed it...........same camshaft.

[CleviteKid]

Hey Grape,

Happy New Year. Sorry but I have not been paying attention to your calculations before, being as I am allergic to turbos and all . . . . . .

Just wondering if you also took into account the pressure on the BOTTOM of the intake valve during compression, power, and exhaust strokes? There is probably 20 psig on the bottom of the intake valve during the exhaust stroke, to counter the 15 psig on top (minus the area of the stem, top side only).

But your basic point is dead on - diesel engines are air pumps and cannot perform any better than the air (or nitrous :eek: ) that we can move through them.

Dr. Lee :cool:

[doncannon]

Hello All,
I hope your New Year is going ok.

JOHN: I checked with Tim@accurate..he said the 4911 and 6.5 inj. are set up for a stock 6.5td

4X4: I love more power...cant get enough...just worried about the 6.2 having enough.

Dr: I will check on the saddles as soon as I get a pan gasket...They are just the points above where the mains mount/bolt on the block?

Robyn: was the cat 3208t hard to install? expensive? on the thermodynamics would a girdle help?

Grape: If that is the case what could i do to help it? would the valves be floating? how would i know?

Thank you all again,
Happy New Year,
Don

[grape]

Originally posted by CleviteKid:
Hey Grape,

Happy New Year. Sorry but I have not been paying attention to your calculations before, being as I am allergic to turbos and all . . . . . .

Just wondering if you also took into account the pressure on the BOTTOM of the intake valve during compression, power, and exhaust strokes? There is probably 20 psig on the bottom of the intake valve during the exhaust stroke, to counter the 15 psig on top (minus the area of the stem, top side only).

But your basic point is dead on - diesel engines are air pumps and cannot perform any better than the air (or nitrous :eek: ) that we can move through them.

Dr. Lee :cool: good point, i'm just going on what the cam grinder said. Which was for the lift and size valves we are using along with the small metric stems we have to add almost 50 pounds of seat pressure to hold the intake closed at 20 pounds of boost, versus N/A. Unfortunately we might start to run into a hydraulic lifter bleed off problem if the valve springs get too crazy.

Not to mention after timing the camshaft yesterday to get an idea of piston to valve, or my case piston through valve, this diesel cam timing event stuff is waaaay weird.

Anybody else got jesel shaft rockers on their 6.5 yet............? LOL i need my head examined.

[arveetek]

Don,

I'm really happy with the power output of my engine. At this point, I basically have more power than my 3/4 ton frame can handle. Here's what I mean: I haven't found a load yet that will pull my 6.2L down and have me wishing for more power. However, I have severly overloaded my little 3/4 ton on occasion. Basically, I have a lot of engine, but not enough truck to handle the loads it can pull. The biggest load yet was a backhoe on a custom-built triple axle 5th wheel trailer (I'll upload pics later). I only moved it a few miles, and had plenty of power, but the truck is really too small to handle those loads safely.

What I'm trying to say is, I think you would by happier with your engine if you modified your engine like I did: open up the engine, lower the compression a little, get the pistons ceramic-coated, and then increase fuel and boost a little more. I don't think stock 6.2L internals can handle much more than what you're giving it. By doing those modifications, you can increase the power output some more and hopefully the engine will hold together.

I see 18 psi on the boost guage from time to time, but the engine has shown no signs of being overworked or on the verge of coming apart. My next item on the list for my engine would be an intercooler, to help lessen the stress on a hot day. So, by all means, if you already have an intercooler, install it anyway. It can't really hurt, but I'm not sure if you'll gain much power. I'd say the biggest gains would be longer engine life due to cooler air induction.

Casey

[doncannon]

Hello all,

where can I get a gauge to put in the pressure chamber to measure the incoming air temp after the turbo? Would a water temp guage work?

arveetek: where did you get the 19.75 pistons? also where did you get the 4" exhaust?

thankyou all again for all your help,
hope everyone is having a good new year,
Don

[arveetek]

Originally posted by Don Cannon:


arveetek: where did you get the 19.75 pistons? also where did you get the 4" exhaust?

The Diesel Depot made me the custom pistons for a really great price. I made the 4" exhaust myself. I found a local shop that specializes in exhaust parts for medium and heavy-duty trucks. They carry all sorts of pipes and fittings in 3" and up. I was able to buy an assortment of elbows and pipe and weld it together myself without much hassle. I purchased a slightly-used 4" Kennedy Diesel muffler from another DP member.

Casey

[More Power]

Peninsular Engine (http://www.peninsularengine.com) sells 19:1 6.2L pistons that they developed for their 250 hp 6.2L marine TD engines.

John Kennedy and Brian Pederson are two 6.5 owners who have used 18-20 psi boost pressure without valve float. Pretty sure there are others. If memory serves, BD sells/sold an exhaust brake for the 6.5 that is regulated at 35 psi exhaust backpressure while in grade-braking.

Jim

[arveetek]

Originally posted by More Power:
Peninsular Engine (http://www.peninsularengine.com) sells 19:1 6.2L pistons that they developed for their 250 hp 6.2L marine TD engines.

Jim The only drawback to Peninsular's pistons is that they only carry them in stock bore sizes. I contacted them when rebuilding my engine, and like most rebuilds require, I needed oversized pistons. But, Peninsular only has stock size pistons, so I was out of luck there.

If the 6.2L in question has cylinder bores within factory specs, then these would be an option, and not a bad price, either.

Casey

[dieseldummy]

Another option is having your local machine shope "top" your stock compression pistons. A good rule of thumb is that .010" takes compression down 1 point on a 6.2/6.5.

You'll know when you make to much power, that's when the crank falls into the oil pan... I've ran 20-25 lbs of boost on a 6.5 with a maxed out -4911 IP. The block it's self had 148K on it when it went, the last 30K had the big boost and fuel. Just something to ponder...

[big61fourby]

Don,

Check the link in my sig. for a gauge. Think it cost me around $80. regular water temp gauge might work, but I've heard others say they respond pretty slow (mine is very responsive). Let me know if you have any questions.

Ben

[doncannon]

Hello All,

I ponder how much power I have now? hmm

Arveetek: I will check with Diesel Depot, too bad Peninsular only makes stock bore. thank you

More Power: Those pistons would be great! Are they running the wastegate turbo for the 250hp?

Dieseldummy: How much could you take off the pistons and still be safe? Wow 20-25 lbs of boost is GREAT!! too bad it about the crank :eek: I really hate when that happens :mad:

Ben: I tried the link...however could not find the gauge.

Thank you all very much,
Don

[big61fourby]

Here's my post from over at the 6.5 page: IAT gauge (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=009442)

My set up uses a temp meter used in industrial processes, so it doesn't look like a regular gauge. That first pic is the gauge mounted under the dash, not a real clean install, but it works. The next couple of pics in that album are of the gauge too, you can see it through the steering wheel by my left foot when seated. One of the downsides is that it requires 120V to operate.

[dieseldummy]

IIRC, Grape once stated that a stock piston is .5" thick, so taking .030" off shouldn't be too big of a problem.

[More Power]

Don, As I recall, all of their marine engines ran a non-wastegated water-cooled Switzer turbocharger.

One of their 6.2L TD marine engines ran to 6500+ hours in a boat...

Jim

[doncannon]

Hello All,

big 61: It is cool!! What was your gauge out of? I have never seen one like that.

dieseldummy: how much would .030" take down the compression? would it be 3. and that would be 20:1 compression? Is this right?

MP: Wow that is great 6500 hrs. Do they run any special pistons, girdle, etc?

thank you all again,
Don

[big61fourby]

Don, I have no clue what the gauge was used for. I imagine some production factory or something. Stumbled accros it on ebay, did a little research, and figured I'd give it a shot. Works great!

[doncannon]

Hello,

dieseldummy: how much would .030 lower my compression ratio?

thank you,
Don