Also, cylinder pressures are higher at lower rpms which is more strain on the rods. Higher rpms at the same power will have lower pressure and momentum in it's favor.
the out come on 650-700hp
- Thread starter jgt1982
- Start date
Boy, this is a can of worms you all opened up, lol. Since Banks was brought up and he holds the fastest Dmax powered vehicle then he makes for a great example. They are making their power well above 4000rpms so tq is low but the HP is higher and they are going 7.17 in the quarter. Food for thought...
Thanks Mark. Makes sense now.
I wasn't trying to discredit Banks at all. Just wanted clarification. :hug:
You good bud, didn't take it that way at all. It's just the perfect example because they spin the crap out of their motors, far higher than I do, lol! I hope that I get some more rpm's when I put the twins back on...
Mark said it better than I did. Gale was describing piston speed in your quote at a given rpm with only a change in stroke unless I misunderstood the article.
Thought this was interesting:
So somewhere in the mix, tension stresses become a bigger issue than compressive forces. Equations are complex. One of the comments said that the rod is most likely to break just after TDC on the exhaust stroke because of the forces involved.
So I guess the calculation we need is how much compressive PSI are the rods subject to at peak torque vs peak hp? torque vs hp is essentially what we are arguing.
also, I wonder if the increase tensile forces of the high rpm's helps keep the compressive forces from shortening rods by reducing the time it is under compression and unloading the compression at a higher rate. I'm sure it increases stress, but it may help keep from "shortening" rods.
I'm tired, didn't sleep last night and may be confusing myself on the matter. I'll sleep on it and see what else pops in my head. There are smarter guys on here than me, I want to hear what they think. :thumb:
Thought this was interesting:
So somewhere in the mix, tension stresses become a bigger issue than compressive forces. Equations are complex. One of the comments said that the rod is most likely to break just after TDC on the exhaust stroke because of the forces involved.
So I guess the calculation we need is how much compressive PSI are the rods subject to at peak torque vs peak hp? torque vs hp is essentially what we are arguing.
also, I wonder if the increase tensile forces of the high rpm's helps keep the compressive forces from shortening rods by reducing the time it is under compression and unloading the compression at a higher rate. I'm sure it increases stress, but it may help keep from "shortening" rods.
I'm tired, didn't sleep last night and may be confusing myself on the matter. I'll sleep on it and see what else pops in my head. There are smarter guys on here than me, I want to hear what they think. :thumb:
head issues? hot spots? I would like to see a 75gpm electric
a 55gpm at idle combined with a stock pump a electric can bennifit by coooling at low rpm, however the stocker will reduce flow from resistance, (combined with a electric)it will still build 32 psi though, however I don't know the volume at that pressure? with just electric?
regardless I agree they don't pump the volume...
is that volume needed though? GM seems to think so.. What is you thought??
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oil cooling,seperate them!
if you don't ,you can only do so much. On a tow rig this is complex and costly, low milage dd or sled puller/race only quite simple.
if you don't ,you can only do so much. On a tow rig this is complex and costly, low milage dd or sled puller/race only quite simple.
head issues? hot spots? I would like to see a 75gpm electric
it will still build 32 psi though, however I don't know the volume at that pressure? with just electric?
regardless I agree they don't pump the volume...
is that volume needed though? GM seems to think so.. What is you thought??
The issue that I have seen with them is they want to vapor lock at rpm/high hp and start melting shit. Technically they need both and the only way to do it would be with two pumps with some sort of variable controller to increase the flow at rpm. When they get hot on the dyno just maintaining light load with two fans going full blast there is an issue. When it happens on multiple trucks then it is no longer an isulated issue with a single truck. That's what got my attention on them.
I agree on the separating the oil/coolant but for guys like me that drive them in the winter that becomes another issue for getting the temps up to operating temp. I have been stewing over this for some time now and will probably address it in the spring time.
I'm glad you started talking about this in the open as you can watch things so much easier on the dyno. I'm going back to a modded stock pump. I need to discuss with you the best way to plumb that also. Nice to see guys posting some tech again in this thread. :thumb:
I understand, it makes sense to me. Im thankful to actually see some intelligent conversation come out of this.
There are many fair points and sound reason stated here. The only real way is to test out the theorys, which has kind of been done already.
Me, I'm example B: I would lug "Candy" down to 17-1800 RPM cruising in OD with my IH 1066 in tow. (30,000 Gross) And the truck is still out there ticking away with 150,000+ on the clock...
There are A: guys out there that have there trucks live under the same circumstances.
Even yet there are those kids that could tear up an anvil, and regardless of mods or tuning, they shuck rods anyway.
Caleb
Yeah, I don't normal share alot of info due to the way most treated me before but it seems to have calmed down so here we are. I personally feel that it might be the reason your head failed this year, not enough cooling to put the heat out of the head under power.
The drama on here is worse than a bunch of little girls...:baby:
But if that's the game I guess I will play...
I too am very thankful of all your shared knowledge Mark, your the man buddy...
I feel that even if you are the only person who has evidence contrary to what is popularly accepted, you should post it.
I, like many others here, am not new to forums or the mindset that comes with them as they grow...and I'd like to think that here at DD we make a conscious effort to keep an open mind for the sake of sharing good tech ideas without letting personal matters interfere.
If you want to gossip and put down members with your "forum seniority" there are plenty of other duramaxforums where you will find this.
Sent from my iPhone.
I, like many others here, am not new to forums or the mindset that comes with them as they grow...and I'd like to think that here at DD we make a conscious effort to keep an open mind for the sake of sharing good tech ideas without letting personal matters interfere.
If you want to gossip and put down members with your "forum seniority" there are plenty of other duramaxforums where you will find this.
Sent from my iPhone.
The drama on here is worse than a bunch of little girls...:baby:
But if that's the game I guess I will play...
I too am very thankful of all your shared knowledge Mark, your the man buddy...
I wouldnt normaly bother replying to this, however you are just feeding to a fire.
the best way is just to ignore drama and add good tech.jmo
Mark
I did see a electric made in Australia iirc that was vvt it was a lower gpm but combined mightwork well. that starts to get aa lot of stuff though.
I understand about cold weather not working good. my race truck runs very cool even on hot days. its just so much easier on race only aplications but you lose fun factor from not dd!
on any of the truck with said vapor lock did they try running higher pressure rad caps? This will raise boil point of coolant system.
with my new system (race only) I'd be tough to even reach100c
During a pull this year one of his heads opened up between the exhaust valves and blew compression into the cooling system.
http://www.duramaxdiesels.com/forum/showthread.php?t=42553
Speculation ran wild but Dave and I both know what this issue was as there was no other damage nd pistons looked like brand new. Dave's was the 2nd or 3rd truck on the dyno that would get hot on the temp guage just cruising under mild load on the dyno. When the head failed like this it kinda connected the dots for me and the rest made more since. As far as a higher pressure cap, not sure that would do much as the factory cap holds a ton of pressure(blown head gaskets) to swell the upper radiator hose to almost twice it's side. Food for thought regardless...