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I currently am looking at my options of upgrading my stock turbo. I am looking to be able to run boost pressure of up to 20 psi. I have heard of guys running 6.5 TD with higher than 20 psi but am wondering what turbos they use. I would like to hear from anyone that is running a high performance turbo on their 6.5; like what turbo they are running, and how much it cost, their boost pressure, and how much alterations it took to install.
More Power
10-08-2007, 15:01
There'll be a new article available on the web site in a few days that discusses turbocharger options for the 6.5 & Duramax. Photos of ones in use and a few different compressor maps are included. :)
Jim
Thanks. I will ldefinitely check it out. So, it'll come out on the 15th?
DA BIG ONE
10-08-2007, 16:36
There'll be a new article available on the web site in a few days that discusses turbocharger options for the 6.5 & Duramax. Photos of ones in use and a few different compressor maps are included. :)
Jim
Can't wait!
signgrafix
10-10-2007, 08:45
I have kind of got the impression that with the high CR of the 6.5 that a high performance turbo will do you no good because you can't use it. You can't run more boost than a stock turbo provides. It would only do you good if you had the lower CR pistons. Is that right?
DA BIG ONE
10-10-2007, 10:17
I have kind of got the impression that with the high CR of the 6.5 that a high performance turbo will do you no good because you can't use it. You can't run more boost than a stock turbo provides. It would only do you good if you had the lower CR pistons. Is that right?
Perhaps, more cfm into engine a lower boost levels is the way to go, lag more likely than not would be issue but upper rpms would be outstanding!
DennisG01
10-10-2007, 12:42
I have kind of got the impression that with the high CR of the 6.5 that a high performance turbo will do you no good because you can't use it. You can't run more boost than a stock turbo provides. It would only do you good if you had the lower CR pistons. Is that right?
Yup. That's why I went the way I did with a new engine. Ron Schoolcraft is even currently working on a plug-n-play, larger turbo. I'll be looking forward to that when he gets it ready to sell! He'd doing a lot of testing on it right now.
Slim shady
10-10-2007, 23:51
Yup. That's why I went the way I did with a new engine. Ron Schoolcraft is even currently working on a plug-n-play, larger turbo. I'll be looking forward to that when he gets it ready to sell! He'd doing a lot of testing on it right now.
did you check this out, we already have a basic bolt in turbo that does what you are asking for.
http://www.thedieselpageforums.com/photopost/showgallery.php?cat=500&ppuser=9327
Perhaps, more cfm into engine a lower boost levels is the way to go, lag more likely than not would be issue but upper rpms would be outstanding!
Exactly. Larger turbo same manifold PSI is same effective Cr ratio but more CFM puts cooler more dense air in the cylinder. Add fuel and you have more power at the same CR and manifold pressure. It can be done at stock CR. 18.1 would just make even more power. The real test is how big can you go before Lag is a problem.
What turbo is that in the pictures?
More Power
10-11-2007, 12:27
Perhaps, more cfm into engine a lower boost levels is the way to go, lag more likely than not would be issue but upper rpms would be outstanding!
Can't get more CFM at a lower boost pressure.... The engine CFM (air flow rate) is defined by the engine's displacement, its volumetric efficiency and the pressure ratio (boost pressure) produced by the turbo.
A more efficient turbocharger compressor just means it produces less heat at a given pressure ratio and flow rate - which is a good thing. :)
Jim
Can't get more CFM at a lower boost pressure.... The engine CFM (air flow rate) is defined by the engine's displacement, its volumetric efficiency and the pressure ratio (boost pressure) produced by the turbo.
A more efficient turbocharger compressor just means it produces less heat at a given pressure ratio and flow rate - which is a good thing. :)
Jim
If your engine is using all of the AFR. Then you can only supply more CFM by adding additional pressure. You can supply more air at a lower boost if you have not hit your max AFR.
AFR = ? air fuel ratio? If so diesel's not like that. I have read it will burn anywhere from 3:1 to 40:1. Maybe thats volumetric or mass ratio I don't know but my point is diesel fuel to air ratio is really wide so its either fuel limited combustion (normally) or air limited (wild HP machines).
2. Jim is a little more technically correct. I believe you know what's what but may mislead some the way you typed it. Pressure is really made by a resistance to flowrate. The engine will "pump" its displacement only. I can't do it justice but Ron has a few posts that make it clearer. You have to be on the same page as to which pressure you are referencing air mass because its compressed in intake. Something about lbs mass of air at ambient vs manifold actual "pump" CFM of engine is the same but Mass of air is different.
So to increase flowrate CFM measured at turbo inlet or exhaust outlet for a modded 6.5 you have to increase sizes and or effeciencies. Or the more air you can push for the given pressure differential across the turbine and or compressor the better.
Air is the only thing that cools the combustion event gasses ie EGT. The block, head, oil and coolant are all there to harness the power and pump heat out radiator and stack coolers that they absorb.
on edit.
OOPS! I guess you mean AFR = air flow rate. Paragraph 2. is still the point. Air flow rate of the 18:1 6.5 "engine pump" is higher than a GM-x can effecienctly supply to build higher HP. I don't think you realistically will run into an air flow rate cieling of the "engine pump" (partly because diesel fuel to air ratio is so wide) its more an effeciency cieling (compression heat of turbo and turbine back pressure) and drivability. Note pennsilar uses a big non wastegated turbo and w/a intercooler on its high HP marine units. But I imagine they roll smoke on WOT acceleration and can't jump up on plane from a standstill like the lower hp units can but top speed is higher.
You explained with much more detail but thats exactly what I am talking about.
Can't get more CFM at a lower boost pressure.... The engine CFM (air flow rate) is defined by the engine's displacement, its volumetric efficiency and the pressure ratio (boost pressure) produced by the turbo.
A more efficient turbocharger compressor just means it produces less heat at a given pressure ratio and flow rate - which is a good thing. :)
Jim
wrong, engine airflow rate in boosted applictions has nothing to do with physical displacement..........camshaft decides how much air goes through an engine while it's under boost.
With a camshaft change you can move more air volume with less boost................
From what I have seen on the 6.5 the heads are very poor as far as the valves, intake and exhaust runners and port size.
A serious port job and some help in the valve and cam dept will certainly help.
With the close proximity that the valves run to the pistons during the overlap time there would need to be some careful calcs done on any cam change. Possibly a faster opening intake may help some.
I agree that a cam change may help BUTTTTT the engine can only hold so much air at any given PSI. If the flow of the intake system, valves ect will allow the cylinders to completely fill to whatever pressure the turbo is pushing then you will have reached the maximum. To gain any more volume of air the pressure will have to climb.
With a slightly different cam grind one may be able to overflow the engine and blast a large amount of fresh air through the cylinder and out the exhaust that would result is a big cooling effect on the EGT.
I really dont think that the 6.5 is that poor of an air pump that it is not filling the cylinders well enough.
The ideal situation would be 2 intakes and 2 exhausts but that is not in the offing.
Even a little bit bigger intake would help but GM did some messing around with valve sizes during the 6.5's production runs and reduced the size slightly to improve durability of the heads.
Personally I would go with as good of a port job as I could do and reduce the imperfections as much as possible.
A larger Xover pipe and of course the largest ehaust system I could fit.
4" will flow all the 6.5 can possibly flow anyway.
If it was 500 inches the situation might be somewhat different but its only 395 cubes.
The RPM range is relatively low so again there are limiting factors in the amount of air it can pump.
As far as the fuel ratio goes, with a compression ignition engine the fuel is popped into that white hot air and burns instantly so it really means little unless you just drown the the thing.
A turbo thats as good or slightly better than the GM 8 will provide all the air this engine can use. One of the biggest issues is the turbo exhaust housing, the thing is restrictive and at high boost and power levels tends to choke things up. This is probably one of the more major limiting factors.
I might consider a custom turbo manifold and housing to eliminate that torturous mess that GM installed. Possibly a twin setup.
Overall there is room for some improvement and it is within reach BUTTTTTTTTTT how Much $$$$$$$$$$ do you want to spend.
IMHO the 6.5 should be setup to run at or around 12-15 pounds even with an intercooler and the little creature will put out some good power and have a fairly good duty cycle.
I personally would not go after the 20+ psi unless the rig is going to be driven by a gauge nut that can keep it out of the crispy zone.
My DaHooooley will push 10-12 PSI and I have not installed an aftercooler.
The exhaust temp will run about 900 post turbo on a hard pull with 8K trailer behind it and this was on a 10% grade for 2 miles.
If more power is wanted than these numbers can give I think another direction is needed.
DMax, Cat, ??????? :)
Jim did some great things with the project truck and the facts just dont lie, but I would not turn just anyone loose with that setup unless they had been heavily briefed on the protocols of running it.
I have educated my daughter on running my 95 as to what to do and what to expect. The EGT was pointed out and the finger waved at the 900 max mark.
She is very good with these things and understands stuff like this.
An exception to the norm.
Good luck on getting more huff in the 6.5
wrong, engine airflow rate in boosted applictions has nothing to do with physical displacement..........camshaft decides how much air goes through an engine while it's under boost.
With a camshaft change you can move more air volume with less boost................
Just wanted to point out. Jim is correct. Engine Air Flow Rate is the maximum air flow in pounds per minute that can be flowed threw an engine at a given displacement/RPM/boost. The mathematics aSSume 100% efficiency. Perfect heads cam etc. Now getting the maximum air flow rate threw engine is another story. Better heads, cam, turbo etc. all help to get to the maximum AFR. The only way you can raise the AFR of a given displacement is more boost, more RPM.
More Power
10-15-2007, 20:10
The hazard with increasing boost pressure in the 6.5 is not so much the boost pressure, but with the associated fueling (& combustion pressure increases). An excess of efficient boost pressure primarily serves to make the engine run cooler and cleaner.
Fuel the engine to produce 10-20% exhaust opacity at 15 psi boost (this is just a light transparent haze), then increase boost to 20. The exhaust will be entirely clear and the engine will run cooler (exhaust & ECT temps) than it will at 15 psi. On the other hand, fuel the engine to produce 20% opacity at 20 psi, and you've increased power another 20-30 (just a guess), and you'll be pushing 250 RW. Can the 6.5 handle 250 RW - with reasonable durability? A lot depends on the build and components used (whether you're using a new AMG block, or old GM oil spray block, or splayed mains, or balanced, or 18:1's, etc.). All the talk of block & crank failures has everyone on the edge of their seat.
I do know Peninsular has sold some number of 400FW twin turbo marine 6.5's. Pen says these are "intermittent" duty engine applications (fire, rescue, law enforcement, etc.). By the way, Pen can get away with talking FW power cuz they have an inhouse engine dyno (and boats don't have wheels... :))...
Personally, I'd feel just fine with fueling for 15, but run 20 for the cooling.
Jim
By the way, Pen can get away with talking FW power cuz they have an inhouse engine dyno (and boats don't have wheels... :))...
this the same dyno that charts 100 hp at 1000 rpm? lol
More Power
10-15-2007, 22:22
this the same dyno that charts 100 hp at 1000 rpm? lol
It would be if the engine made 525 FW lb-ft of torque at 1000-rpm.
I'm with you though... We should hold every performance part vendor's feet to the fire on their advertised power/tq claims. Would be fun to hold a dyno shootout... don't ya think?
Jim
DA BIG ONE
10-16-2007, 04:08
wrong, engine airflow rate in boosted applictions has nothing to do with physical displacement..........camshaft decides how much air goes through an engine while it's under boost.
With a camshaft change you can move more air volume with less boost................
I had built a hi-pressure turbo gas 4 banger then used a radical hi-performance bumpstick for N/A engine power increase from bumpstick was shocking to say the least. Because un-burnt fuel gets past turbo resulting in major EGT increase and flame an issue if considering using this type of setup for street.
Good N/A bumpstick would be great addition to what is out there for the 6.2/6.5 TD.
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