How much boost pressure do you think the head gaskets will take before you start having to modify them(the heads)? That is after the aftermarket turbos become available.http://www.dieselplace.com/forum/smileys/smiley2.gif

75PSI on LB7


110PSI on LLY


LLY is a far superior motor http://www.dieselplace.com/forum/smileys/hihi.gif

I thought the only changes to the LLY was that they moved the injectos and the new turbo, so how can the LLY be a far superior motor? You act as though they redesign to whole motor. Minus the different turbo, it is the same motor with the injectors in a deifferent location. Edited by: BassinRVer

I think Dmax Tim was being sarcastic.http://www.dieselplace.com/forum/smileys/smiley2.gif I hope the first # he threw out there for the LB7 is close to the max boost(although I think it is a bit high) we can run though. I hope we get a few more responses.

My thoughts?


FWIW, 50 LBS-60LBS is what i think we can do reliably on a stock gasket and non studded block without o-rings.


This is my best guess based on clamp load between block and head vs surface area / Compared to the CTD clamp load/surface area.


They pop at over 50-58+ PSIG


Ass U Me the intake and exhaust valves have springs that can keep up. that is an even larger question.


Truthfully, we have another potential problem, and that is the intake air feed pipe that divides the airflow between the 2 cylinder banks. There is some gain to be has there even running stock boost pressure as well as.....other small tweakshttp://www.dieselplace.com/forum/smileys/smiley9.gif

spill it juice,gains, problems, tweaks?

spill it juice,gains, problems, tweaks?


NEVER NEVER NEVER EVER SPILL THE JUICE!http://www.dieselplace.com/forum/smileys/hihi.gif


Problems will lie in the aluminum cast intake. Stud mounted, but the sealing setup i do not think (might be wrong here, but it won't be the first timehttp://www.dieselplace.com/forum/smileys/smiley9.gif)it will hold anything past 60PSIG


Tweaks to the rest IE: Port matching etc.... would i do that and not tell anyone about it?http://www.dieselplace.com/forum/smileys/hihi.gif


Geez i thought everyone would have done it by now.... sheesh there goes another little tidbit of information.


Take it apart and check the 'meat' of the intake ports compared to the gasket size and intake..... take your time and do some mild work... you will see some gains. This is also why i cannot run higher than 34PSIG post cac boost on a stock or ported turbo at sea level with a 'stoopid' box. with even less restriction in the intake pathing and no throttle plate there is less 'boost stacking' and therefore less flow impedance therefore more RPM in the turbine (closer to surge line ) in order to maintain 34PSIG. There are more gains to be had in the heads, and i do see a set on ebay (with all the kit needed to retorque a set of DMX heads this will be the most cost effective way for a DIY like me to get on the project)..... i might have to procure a set and try more aggressive work on them and see what the results are. Keep in mind i have a real job and limited $$$ otherwise i would try blowing up s'more stuff in the quest for power. But it does make me wonder what other 'corners' GM cut that i might have to put back onhttp://www.dieselplace.com/forum/smileys/Rock On.gif


There ya go. A freebie worth 15RWHP plan on a long weekend to do it yourself.


You can make more power with less 'observed' boost if you maximize flow potentials!Edited by: Got Juice?

I think Dmax Tim was being sarcastic.http://www.dieselplace.com/forum/smileys/smiley2.gif I hope the first # he threw out there for the LB7 is close to the max boost(although I think it is a bit high) we can run though. I hope we get a few more responses.











http://www.dieselplace.com/forum/smileys/hihi.gif





YES, being sarcastic since the LBs are having all the extreme fun and we got http://www.dieselplace.com/forum/smileys/smiley35.gif

I don't know how many have blown the heads due to psi. I blew mine because of a close to hydro lock situation (lifted head). ATS ran the twins at about 60 psi with out trouble, that I know of, but who knows. These heads are tougher than most think. I would like to get some real hard data on it though. Any crash test dummies out there?

Got Juice - While you're at it, are you going to check into heavier valve springs??? I would imagine that along with your gasket-match porting, perhaps a stronger valve train may be in order too...I have no clue if a guy could put bigger valves in the duramax head or not?? If so, get some made out of stainless, get the guides cut back for better flow along with some decent bowl porting...If all of this is possible, I would imagine another 20-60 horsepower is available right there if the has enough material to be ported/modified this way...Hmmm I might have to get a spare set of heads and spend a few hours with the air grinder! It would be nice to get a head that was beyond repair and cut it with a band saw to see just how much meat is in the ports, so we knew how much we could machine without hitting coolant ports.....

Got Juice - While you're at it, are you going to check into heavier valve springs??? I would imagine that along with your gasket-match porting, perhaps a stronger valve train may be in order too...I have no clue if a guy could put bigger valves in the duramax head or not?? If so, get some made out of stainless, get the guides cut back for better flow along with some decent bowl porting...If all of this is possible, I would imagine another 20-60 horsepower is available right there if the has enough material to be ported/modified this way...Hmmm I might have to get a spare set of heads and spend a few hours with the air grinder! It would be nice to get a head that was beyond repair and cut it with a band saw to see just how much meat is in the ports, so we knew how much we could machine without hitting coolant ports.....





Our stock springs are fairly stout. I have seen 454BB springs with less initial action to them. Double coil springs are definately not an option (i should say probably not an option due to clearances and possible coil bind) In truth, i am NO expert on this stuff, i am blindly feeling my way around without a map.... which is to say pushing beyond what i know in terms of a DMX. There is another DMX running around with ported intake and heads as well (found that out last week) Since we do not rely on helmoltz principals (inducted pressure wave resonance) for our intake air charge (turbo forces air in unlike a N/A motor) we should be able to unshroud the intake area for some gain in performance.3 angle or back cut on the valves is not a good idea with our current EGT problems, we need that 'heatsink effect'.


Bowl porting??? i do not think that will help us as we do not want to interfere with the quench area.... we could easily get too much variance from cylinder to cylinder especially doing it by hand... which would make some cylinders run cooler / weaker than the other or worst case scenario really mess up a cylinders CR... i don't want to try that out too badly. The DMX LB7 has had a lot of good engineering into it... there is some improvements in remocing excess casting flash etc, nothing too major, just a PITA to get too and it is time consuming. I do believe we have larger CAC ducting than the LLY as well as a more direct inlet air feed...the LLY intake is a bit 'squished'. I dunno, would someone with better smarts than me please start on the road i have been travelling? I need some expert help here.


Thanks


J

Juice - By "bowl porting" I mean in the heads, not the cylinder or
piston...Just smoothing out the "bowl" under the valves for a smoother
entrance of air or exit of air depending of course on which valve we're
talking about....This will have zero effect on compression ratio...You
do bring up a valid point that it would be very difficult to get every
port, valve bowl the same, thus the possibility of making the cylinders
un-equal......I've ported a few gas heads before, but I have yet to
monkey with a diesel...Having said that though, the same principles
apply as far as getting air in and out....

dammit, you're making me think too much here..http://www.dieselplace.com/forum/smileys/smiley17.gif

You don't have to be real exact smoothing out the ports and guide "bowl". It all helps, tho you may have slight differences from hole to hole on the torque curve. The prob is cutting it too much and raising the entire torque curve so high it's makes it a single purpose vehicle. The more you grind out, the more low end you'll lose, especially inline Cummins. Seems to work best just makin 'em look nice and opening up the intake as big as you can from the first tube...T

Juice - By "bowl porting" I mean in the heads, not the cylinder or piston...Just smoothing out the "bowl" under the valves for a smoother entrance of air or exit of air depending of course on which valve we're talking about....This will have zero effect on compression ratio...You do bring up a valid point that it would be very difficult to get every port, valve bowl the same, thus the possibility of making the cylinders un-equal......I've ported a few gas heads before, but I have yet to monkey with a diesel...Having said that though, the same principles apply as far as getting air in and out....
dammit, you're making me think too much here..http://www.dieselplace.com/forum/smileys/smiley17.gif



Ok, on the same page now, yes some bowl porting in the velve area should help us. Until i get my spare set of DMX heads though i am not to keen on breaking out the die grinder or dremel on my Daily driver.


I think to properly do this, we would need to do one of 2 things.


Extrudehone the intake and exhaust ports first. Then measure flow in both intake and exhaust. Once everything is as equal as we can make it, then move to the valve area and do the same flowbench tests.


Then i would expect to see some real gains in those areas... someone has to be doing it.

Absolutely juice...I think a good baseline test of the duramax heads on
a flowbench would help a ton....then, with each modification, see if a
guy gained or lost in the flow departement..

Absolutely juice...I think a good baseline test of the duramax heads on a flowbench would help a ton....then, with each modification, see if a guy gained or lost in the flow departement..


Caution on the turbo when porting the intake. Mo betta cylinder filling more flow=less observed boost Post CAC... that does not mean TURN UP THE WASTEGATE to compensate for the 'observed ' pressure drop.


Back away from that actuator now! That is partially why we need more turbo... with some porting work (not alot just basic cleanup) you will observe more power and LESS boost. But then again, i am just a dummy trying for 600 or better on #2 only. It will be this year (I Hope)

Seems to work best just makin 'em look nice and opening up the intake as big as you can from the first tube...T





Yup

[/QUOTE]


Caution on the turbo when porting the intake. Mo betta cylinder
filling more flow=less observed boost Post CAC... that does not mean
TURN UP THE WASTEGATE to compensate for the 'observed ' pressure drop.


Back away from that actuator now! That is partially why we need more
turbo... with some porting work (not alot just basic cleanup) you will
observe more power and LESS boost. But then again, i am just a
dummy trying for 600 or better on #2 only. It will be this year (I Hope)[/QUOTE]

I think that's why porting would help so much juice....better cylinder
filling, (or should I say more efficent?) With a cylinder head that was
flowing to it's maximum capability, we culd get better gains out of all
of the other power-adders out there. Next thing you know we'll be
looking into custom camshafts too http://www.dieselplace.com/forum/smileys/smiley17.gif

Next thing you know we'll be looking into custom camshafts too http://www.dieselplace.com/forum/smileys/smiley17.gif






Yeah, I asked about this a year or so ago. If I recall correctly, there was a member who knew someone who was doing cylinder head and turbo porting, as well as looking into making a "hotter" camshaft.


I've asked this before as well: Does anyone know what the valve clearance specs are? Should they ever be checked/adjusted? You can tune the torque peak to occur at different rpm's on a gas engine by varying valve clearance specs, can we do this with our roller cammed roller lifter equipped Duramax engines?

its a hydralic roller so no. you can adjust lash and move the power band around a bit on a solid but not on a hydralic. Gasser or disel its still changing your cam timing a bit so it would have an effect. One thing some racers do with thier hydralic cams is to set em to were the plunger is almost colapsed. There ussually isnt much to be had there though but every little bit helps. But for us with the rpm we are running and such doing this aint no big thing I would think? http://www.dieselplace.com/forum/smileys/smiley5.gif one way to find out. Are the rockers pedestal mount? I forget?http://www.dieselplace.com/forum/smileys/smiley5.gif

what about using higher ratio rockers? Has anyone thought about this on a diesel?

I think it's a solid roller lifter...at least that's what I thought I read initially.

It's a solid. I got a real good look at it when I did the injectors. GM lists it as a mechanical roller.

its a solid roller? I'm spewing wrong info again I guesshttp://www.dieselplace.com/forum/smileys/smiley9.gif I gotta stop going off my memory.


May as well do a cam instead of some rockers if you are going that wroute. JMO

Any one know of what the cold and hot lash are for the intakes and the exhausts???

Don't forget about the exhaust, while you're at it... The path from the
heads to the turbo is very restrictive, and building a good set of
headers would show real gains. Unfortunately, there isn't much space
available for such a system. http://dieselplace.com/forum/smileys/smiley19.gif
Insulating the headers would help, even on a stocker. As for
ports- I'm waiting to see if any of our members with thicker wallets
than mine will pay to have a set CNC ported, and build a good intake
manifold to go with it....and if they will tell anyone about it, should
they go that route http://dieselplace.com/forum/smileys/smiley4.gif.

Don't forget about the exhaust, while you're at it... The path from the heads to the turbo is very restrictive, and building a good set of headers would show real gains. Unfortunately, there isn't much space available for such a system. http://dieselplace.com/forum/smileys/smiley19.gif Insulating the headers would help, even on a stocker. As for ports- I'm waiting to see if any of our members with thicker wallets than mine will pay to have a set CNC ported, and build a good intake manifold to go with it....and if they will tell anyone about it, should they go that route http://dieselplace.com/forum/smileys/smiley4.gif.


Don't i know it.


But this is at best a stopgap in our current turbo situ.


to really take advantage of the porting, we need more turbo.


Yes i am observing less boost, lower EGT's (100-120F) more power (and more barking) but we are out of airsupply.


unfortunately working on the exhaust at this point is not feasable because of our turbo right now.

Yes, Juice, you're right. And the space problem comes up with turbo
upgrades, as well. But hey, who needs all that crap inside the dash-
just yank it all out and make some space for the important stuff, eh?http://dieselplace.com/forum/smileys/hihi.gif

Yes, Juice, you're right. And the space problem comes up with turbo upgrades, as well. But hey, who needs all that crap inside the dash- just yank it all out and make some space for the important stuff, eh?http://dieselplace.com/forum/smileys/hihi.gif


LMFAO...bigger Juicegrips Eh? Hopefully we will have some turbo options this year to make life (and EGT's) easier.


I should say (tongue planted firmly in cheek here) that porting the Exhaust area is not a total waste of time, because when a bigger turbo does become available you will have that job done.

I'll go warm up the air-chisel....

I'll go warm up the air-chisel....


PLASMA CUTTER!http://www.dieselplace.com/forum/smileys/Rock On.gif

Figuring we have to make less power per hole compared to a dodge and I also believe better sealing(or am I wrong? how thick are our castings, what is our bolt placement like, gaskets as good ect???) Wont we be able to make more HP on a stock gasket than a dodge? Isnt the HP level what is actually killing the dodge gaskets and not how much boost they are swinging? Should the dodge guys be saying" it will hold to about x rwhp not x boost?" water meth asid since i think that has claimed a few duramaxes due to hydrolockinghttp://www.dieselplace.com/forum/smileys/smiley11.gif, just HP number what do you think the gaskets will go at?


Anybody up to take some bets? In theory and all speculation of coursehttp://www.dieselplace.com/forum/smileys/smiley1.gif

Didn't GJ already blow his head gaskets with 550 HP with the VA 200+?

BTW, juice, you need to learn to drive. I havent barked my turbo in months. Just dont lifthttp://www.dieselplace.com/forum/smileys/hihi.gif Its like the sure fire way to eliminate hangovers, you cant get hung over if your still drunkhttp://www.dieselplace.com/forum/smileys/hihi.gif


or on a serious note, you getting em on upshifts?

There have been many over the 550 mark with happy headgaskets, I didnt know you poped yours juice? both one none?

Didn't GJ already blow his head gaskets with 550 HP with the VA 200+?


Nope, headgaskets fine.


Turbohttp://www.dieselplace.com/forum/smileys/smiley11.gif

Figuring we have to make less power per hole compared to a dodge and I also believe better sealing(or am I wrong? how thick are our castings, what is our bolt placement like, gaskets as good ect???) Wont we be able to make more HP on a stock gasket than a dodge? Isnt the HP level what is actually killing the dodge gaskets and not how much boost they are swinging? Should the dodge guys be saying" it will hold to about x rwhp not x boost?" water meth asid since i think that has claimed a few duramaxes due to hydrolockinghttp://www.dieselplace.com/forum/smileys/smiley11.gif, just HP number what do you think the gaskets will go at?


Anybody up to take some bets? In theory and all speculation of coursehttp://www.dieselplace.com/forum/smileys/smiley1.gif


The term BMEP is an engineering term that means Brake Mean Effective Pressure. Mean is another word for average, which in this case means average effective pressure of all stroke cycles. This is used to evaluate all engines whether they are Two or Four Cycle.


BMEP is a function of temperature of the gases in the cylinder. To increase the temperature you need to burn more fuel, thus making more heat. Or another way is to make better use of the existing fuel.


Torque is a function of BMEP and displacement only. HP is a function of torque and rpm.


It can be said a high BMEP and a low rpm, or a low BMEP and a high rpm, can equal the same power. Larger valves, ports, pipes, compression, etc. all come into play to increase the volumetric efficiency of the engine. The most effective is to increase the number of cylinders. The more efficient it is, the higher the average pressure or BMEP.


Pressure increases by compression alone can do wonders to a stock engine. Note that after compression gets very high it starts to work against you in pumping losses, and in the amount of heat lost to the surrounding parts. So in a nutshell, Higher boost equates to a higher BMEP and more stresses to the sealing materials and fasteners of the head. USUALLY the headgasket does not fail without warping the head slightly which allows the headgasket room to 'push out'. This is also why studs are preferred to bolts as you get more clamp load for a given fastener torque, which in itself can resist the forces of higher cylinder pressures. More boost means higher BMEP. Most of the HP increases from Crystal Meth comes from the vaporization of the water from liquid to superheated gaseous state that effectivly raises BMEP. Yes, the methanol acts as a fuel, but that is really secondary to what is happening within the cylinder itself upon ignition. On edit: The reason we see an EGT drop when running Crystal meth is the energy absorptive state that occurs when we change a liquid to a gas. In this case, we are changing the water from a liquid state to a gaseous one, and that requires energy to do so, which in this case is heat; therefore the EGT reduction... the water has 'absorbed' the heat to a higher energy state to achieve a gaseous state. A point of diminishing return can happen (catastrophically i might add) when there is too much liquid and not enough heat to render said liquid to a gaseous state.... HYDROLOCK anyone?


http://www.epi-eng.com/ET-BMEP.htm


http://energy.power.bmstu.ru/e02/diesel/d215eng.htm


http://www.btinternet.com/~ucrs/ucrs/rl/rl430.htmlEdited by: Got Juice?

Juice........ you don't know Jack.

Whaddaya mean- He invented, out of necessity, the latest state of the art-


PlasmaGrips http://www.dieselplace.com/forum/smileys/hihi.gif

Hey where's PEANUT? .............. Hey NUT! .... where are ya?


Nut eu'll tell ya....... it's the stickers man, the stickers...that's what really makes ya fast. All that fancy talk about "air" and stuff......... who does O'le Juice think he's kidd'n.





Sticker's!





Burner-------------> http://www.dieselplace.com/forum/smileys/smiley4.gif

The silence in this post is deafaning, i thought BMDMAX or MTomac or Steve Cole John Kennedy would have something to add to this...C'mon guys, i need some help here!

I saw my first Dmax head the other day for a few minutes. Weirdest head I've ever seen. Good quality casting, just bizarre ports. The boss around the exh guide looks like it would really show big flow gains by some porting. It's very large and greatly reduces the little ports cross section. Not sure how long the guides are, but I'd make it flush if the guides are long enough.

I guess there is just too much speculation right now. I fully agree that porting and polishing will yield gains, I have seen most of the parts in this equation to know that there is fat that can be trimmed.


As far as max boost? Nary a clue. Too much secret squirrel stuff. Until the masses can easily add a bigger turbo or a couple of em I don't think we have enough test mules running around with the necessary goods to really find out. Those in the know certainly are not telling.


I do know the heads will hold at least 40 pounds until the spinny thingy screams in agony and blows up. http://www.dieselplace.com/forum/smileys/hihi.gif Then again I don't suppose that is news to anybody. http://www.dieselplace.com/forum/smileys/smiley1.gif

I saw my first Dmax head the other day for a few minutes. Weirdest head I've ever seen. Good quality casting, just bizarre ports. The boss around the exh guide looks like it would really show big flow gains by some porting. It's very large and greatly reduces the little ports cross section. Not sure how long the guides are, but I'd make it flush if the guides are long enough.








I have a friend who is an engineer at Chrysler/Jeep Truck. A couple years ago they had a Duramax engine there to look at. Now this guy is used to seeing Mercedes diesel engines, since they do a lot of European development. Long story short, he said the Duramax head was the best designed diesel head he had ever seen.Edited by: GSXRTURBO1

LOL? that's it?


Steve, John, anything else to add?


Geez i tried to keep it somplehttp://www.dieselplace.com/forum/smileys/smiley9.gif

so I take it 30 isnt bad? I get turbo barks all day on upshifts.......

I see 30 quite a bit and have only barked it once.