Some of you may have heard of Triples.....

[Ben46a]

I've always been a fan of KISS-keep it simple, stupid, And i can see the niche for twins on a driver that wants to work and play where a big single wont fit the bill. But triples on anything but an all out mod truck is just plain rediculous. especially for making a hair over 700 hp like the video on the other site depicts. Thats Small twins territory.

 

[juddski88]

that dyno of JDWOP's truck, i have a feeling, wasn't even close to pull potential of that build and mods are putting out a lot more power than 710, they arent going to downsize

i understand your view now nathan, thank you :hug:

if i put twins on my build and get smoked by a tripled-goat i am going to be sooooooooooo pissed:spit:

 

[McRat]

I still believe the best solution for producing 60+ psig of good air will end up being a big single mated to a supercharger. With big/little compound twins, the small charger is going to be a restrictor at high RPM, but positive displacement superchargers do not care. You will be able to run 14:1 compression with big injectors and idle fine, and have boost at all engine speeds.

Someday I will get around to playing with it. Need a decent mill first.

 

[Idaho CTD]

The downside to superchargers is efficiency. They can't hold a candle to a turbo. So your making the motor produce more hp to get the same results at the rear tires providing they make a supercharger big enough for the application.

 

[McRat]

The downside to superchargers is efficiency. They can't hold a candle to a turbo. So your making the motor produce more hp to get the same results at the rear tires providing they make a supercharger big enough for the application.

Modern positive displacement superchargers are pretty efficient, I'm thinking even more efficient than turbochargers depending on RPM, but their main failing is that they are "constant". Always on, at all RPM, all loads.

But that is what makes them desireable for a hi-po diesel application. The boost exists at all RPM's.

 

[juddski88]

can you give an example of one pat?

 

[McRat]

Detroit Diesel two-strokes. The supercharger doesn't boost much, and doubles as a reed-valve. The turbocharger feeds the roots blower.

When you see a supercharger like "8-71", what that means is it's from a 8 cylinder Detroit with 71 ci per cylinder.

As far as a Dmax application, there are several out there, with varying degrees of success. But remember, when people first started twinning Dmaxes, they weren't more powerful than the single-turbo trucks at first. As more people play with this, you'll see better and better results. Plumbing would be a lot simplier on a Cummins though.

 

[MadMaxx61]

I want to see this beast LMM finished and running.

http://www.duramaxdiesels.com/forum/showthread.php?t=8982

 

[WolfLMM]

I still believe the best solution for producing 60+ psig of good air will end up being a big single mated to a supercharger. With big/little compound twins, the small charger is going to be a restrictor at high RPM, but positive displacement superchargers do not care. You will be able to run 14:1 compression with big injectors and idle fine, and have boost at all engine speeds.

Someday I will get around to playing with it. Need a decent mill first.

Pat, I have tons of decent mills. Get me a model and I will get you a part!

 

[Turbo Buick 6]

Pat, I have tons of decent mills. Get me a model and I will get you a part!

Wanna sell one really cheap

 

[Leadfoot]

This could be totally off base here but....

When people started pushing singles for more power, we started seeing EGT's increase. A bigger single was used to keep EGT's in check but low end suffered (and so did towing). Then twins came out, at first there was not much gain in overall HP, but EGT's and low end towing shined, as people worked on them the power numbers seemed to be higher than singles too. It also seemed like twinned motors at X power levels were living longer than those running the same power on a single. Now we have twinned motors that are having issues with heat (Pat's Bonneville motor and the mormon missle) as we did with singles when we pushed them to their limit. It seems like we may be finding the limit for twins in this specific application (long WOT runs).

Not saying the 3 turbo setup is the "magic pill", but would make sense in the evolution of power to keep engines alive and "cool". There is a reason why the big boys (tractors and semi's are running them), and I would put money on the fact that it's due more for engine longevity than anything else.......I have a feeling projects like the Mormon Missle may have to consider a setup like this (not for power output, but for survivability).


Again I could be way off base here......

 

[Idaho CTD]

Heat soak and intercooler/plumbing restriction are some of the biggest reasons for not keeping the egt's down with twins. Triples won't magically fix that.

 

[Leadfoot]

Heat soak and intercooler/plumbing restriction are some of the biggest reasons for not keeping the egt's down with twins. Triples won't magically fix that.

Not trying to stir the pot, just trying to learn.

By heat soak you mean as a part is in contact with heat it continues to absorb it until equilibrium is reached?? At some point (1 turbo, 2 turbos, etc), the incoming air charge reaches a max temp and the parts will absorb heat up until they become close to or the same temp as the incoming air. The intercooler and plumbing become a bottle neck and will only flow so much air. The thing I don't understand is that efficiency equals less heat into the intake air charge, and is why twins are better at cooling than a single, why would not a third turbo do even better if it helps efficiency? I understand given the current constraints of off the shelf intercoolers and plumbing twins are probably enough, but as people are thinking outside the box if a custom plumbed/intercooled setup were to be feasable wouldn't a third turbo be more efficient if setup correctly?

Your twin kits seem to be the ticket for those that tow or are looking for a 1000hp capable daily driver, but what's the next step.....is it bigger twins and better plumbing? I guess I'm trying to find out from those who know more than I do (which are most of you) why 3 turbos are a detriment besides the space and plumbing arguments? There are some pretty ingenious men/women on here who would be able to "fit it" (you being one of "them").

 

[TrentNell]

The only reason twins run cooler on EGT's is pure volume, heat soak is actually worse because the air is compressed twice which in turn creates more heat . I can see that it being compressed 3 times with 3 turbos, seems like it could be worse ............... maybe ................... the question is if enough volume could be made to offset it ?

My next project when the truck is running is to get an actual IAT temp sensor in the Y-bridge to see if the intercooler system needs some attention , or just switch to W/A over the winter , Simon has been tempting me with his new setup he is working on :cool2:

 

[Leadfoot]

The only reason twins run cooler on EGT's is pure volume, heat soak is actually worse because the air is compressed twice which in turn creates more heat . I can see that it being compressed 3 times with 3 turbos, seems like it could be worse ............... maybe ................... the question is if enough volume could be made to offset it ?

My next project when the truck is running is to get an actual IAT temp sensor in the Y-bridge to see if the intercooler system needs some attention , or just switch to W/A over the winter , Simon has been tempting me with his new setup he is working on :cool2:

I could be wrong (have been before), that as air compresses it heats up at a fixed rate (Boyle's Law) assuming several non variable conditions. In a turbo charger or multiple turbo charger setup I thought how much the air heats up was due to the efficiency of compression. The more efficient you are at compressing the air, the less heat that is created.

I have heard a big single running 50PSI of boost has a higher IAT than a well matched set of twins at 50PSI.

If the above statements are false (than disregard my comments), if it is true then finding more efficient ways of creating boost can be ONE of the factors to help lowering IAT and helping to keep parts from melting. Artificially cooling the air (Water to Air intercooling, water injection, etc.) may work, but I was thinking along the lines of not getting the air so hot that it has to be artificially cooled. Maybe there is no way around it.......

 

[Leadfoot]

or just switch to W/A over the winter , Simon has been tempting me with his new setup he is working on :cool2:

W/A seems to be the ideal setup for a puller and/or drag racer that see's short runs, but I'm thinking for the long haul (land speed records or even daily highway towing).

W/A can cool the intake charge down furthur than a A/A intercooler, but as it cools the intake charge, the water returning to the reservoir brings heat (the heat absorbed during intercooling) back with it. Eventually the "cold source" (ice, water, liquid nitrogen, etc) will heat up and become ineffective whereas an A/A will always have fresh air to cool it. You could run a refrigeration system in the back to constantly cool the W/A, but that it just another headache.

It's like the nitrous bottle, great for short bursts (such as drag racing) but not great for long hauls as it needs refills/maintainence. The sad part is I probably won't need either one, but an issue has arrisen (in all platforms of turbo charged engines) and it would be cool (pun intended) to find a viable long term solution. I think there are enough great minds on this and other forums to do it if we work together. Sometimes stupid ideas give way to brilliant ones....

 

[juddski88]

The only reason twins run cooler on EGT's is pure volume, heat soak is actually worse because the air is compressed twice which in turn creates more heat . I can see that it being compressed 3 times with 3 turbos, seems like it could be worse ............... maybe ................... the question is if enough volume could be made to offset it ?

My next project when the truck is running is to get an actual IAT temp sensor in the Y-bridge to see if the intercooler system needs some attention , or just switch to W/A over the winter , Simon has been tempting me with his new setup he is working on :cool2:

what you say here, compressed 3 times, would it still hold true if the triples were still only acting as 2 stages?

i also am a firm believer in w/a intercooling for competition, but longevity at 650+ hp, daily driven is what i am after, then a quick (maybe 4hrs) to swap to competition mode for a race day.

 

[juddski88]

W/A seems to be the ideal setup for a puller and/or drag racer that see's short runs, but I'm thinking for the long haul (land speed records or even daily highway towing).

W/A can cool the intake charge down furthur than a A/A intercooler, but as it cools the intake charge, the water returning to the reservoir brings heat (the heat absorbed during intercooling) back with it. Eventually the "cold source" (ice, water, liquid nitrogen, etc) will heat up and become ineffective whereas an A/A will always have fresh air to cool it. You could run a refrigeration system in the back to constantly cool the W/A, but that it just another headache.

It's like the nitrous bottle, great for short bursts (such as drag racing) but not great for long hauls as it needs refills/maintainence. The sad part is I probably won't need either one, but an issue has arrisen (in all platforms of turbo charged engines) and it would be cool (pun intended) to find a viable long term solution. I think there are enough great minds on this and other forums to do it if we work together. Sometimes stupid ideas give way to brilliant ones....

kinda like de-lipping pistons or stroking the engine.... or hell, running EFI Live instead of an "Extreme" program was a "handicap" for a while there

i like where this thread is going, thank you chris, now we just need someone whose trying this theory to step up and add their opinions :hug:

 

[Idaho CTD]

First off 2 turbo's in a compound situation are less efficient then one. Every time you add a turbo you loose efficiency. The reason they make more power is it allows you to run a larger turbo (as the primary) then you would normally be able to as a single turbo. Think about it for a second......you have to blow nearly twice as much air through a smaller turbo. That smaller turbo also chokes down the exhaust stream. But it drives nice and has low egt's . The low egt's comes from the boost pressure being higher, packing more air in the cylinder per stroke.

By heat soak I mean the heat needed to make a given hp can't neccessarily be cooled by the coolant/water injection/intake temps.

 

[Leadfoot]

First off 2 turbo's in a compound situation are less efficient then one. Every time you add a turbo you loose efficiency. The reason they make more power is it allows you to run a larger turbo (as the primary) then you would normally be able to as a single turbo. Think about it for a second......you have to blow nearly twice as much air through a smaller turbo. That smaller turbo also chokes down the exhaust stream. But it drives nice and has low egt's . The low egt's comes from the boost pressure being higher, packing more air in the cylinder per stroke.

By heat soak I mean the heat needed to make a given hp can't neccessarily be cooled by the coolant/water injection/intake temps.

Cool, thanks for the explanation. Starting to make a little more sense. If I understand what you are saying is that it takes more exhaust power to run a compound turbo than a single (less efficient), but even though it takes more power to run you see more boost.

I assume that is where drive pressure and boost come in. You want to make as much boost as possible with as little drive pressure as possible (in an ideal world). Everytime you add a turbo (restriction), the drive pressure goes up (in theory), and at some point the added drive pressure negates the gains in boost????

Am I close?

I'm assuming that is why Ford is trying to use a single exhaust wheel and two inlet wheels on a common shaft. Basically 1 bottleneck (exhaust wheel) running two impellers instead of two bottlenecks. Yes it's more weight to spin, but less restriction in the exhaust.....?