Twin turbo dynoed HP...

[Morse]

There's a lot of talk of how much power everyone is now pulling out of a single turbo. . Over 600 hp on a single is very possible. . So what kind of power is everyone getting out of their own twin turbo setup. . This could be a good way to compare what turbos just work, and what turbos really work well together. .

 

[Fishin Guide]

There's a lot of talk of how much power everyone is now pulling out of a single turbo. . Over 600 hp on a single is very possible. . So what kind of power is everyone getting out of their own twin turbo setup. . This could be a good way to compare what turbos just work, and what turbos really work well together. .

Better yet, how much of that horsepower is sustainable for more than a few seconds?



You can build a single to go to the moon, but you may not be able to drive it. Not saying that guys don't drive these 600HP trucks with a single.



For most of us, driveablility, cool EGTs while loaded or extended periods on the go pedal is what makes twins so attractive.



HP is cool to talk about. But, I have seen more than one 400+ hp twin'd truck flat outpull bigger horsepower trucks. Not to hard when they get to use all of thier available horsepower. Some of these big singles would have to back out due to EGTs or can never get the load moving without turning the world black.



Dave

 

[Jim Fulmer]

Even Twins will not sustain all of HP, small Twins 35/3B like I ran now years ago do great..... 670 on #2 but won't hot EGT's off as those numbers net 1800+ but will not hold more than 425-450... . if that towing.



Jim

 

[Diesel Freak]

Better yet, how much of that horsepower is sustainable for more than a few seconds?



You can build a single to go to the moon, but you may not be able to drive it. Not saying that guys don't drive these 600HP trucks with a single.



For most of us, driveablility, cool EGTs while loaded or extended periods on the go pedal is what makes twins so attractive.



HP is cool to talk about. But, I have seen more than one 400+ hp twin'd truck flat outpull bigger horsepower trucks. Not to hard when they get to use all of thier available horsepower. Some of these big singles would have to back out due to EGTs or can never get the load moving without turning the world black.



Dave

Dude, ya beat me to it!!!! :-laf

 

[Jim Fulmer]

One thing is for sure, towing HP get's your RV there faster, Dyno power gets your name know and on the net



Jim

 

[Fishin Guide]

One thing is for sure, towing HP get's your RV there faster, Dyno power gets your name know and on the net



Jim

Maybe I should twin this truck and tow a single charger dyno queen around? Cause it ain't gonna work the other way around! :-laf



And Cliff, I am just here to help.



Dave

 

[willyslover]

usable HP is the key. . Jim your and Cliff are spot on with yor thoughts. .



I rarely use the full power towing, and most pften don't have the box on at all when hooked up to the 5er. . however the twins allow much improved towing especially in the mountains. to keep 60/65 up the steepest hills is a easy task now while the EGT's and water temps are in check and the oil temp is still at or under 205



but to acheive all the goals of usuable power towing and a play rig is a very tall order... on my 6 speed rig, Jammer 5's are a bit too much for towing as I tend to load the 5er with diesel smoke/soot in the cabinets. . so ya have to drive very light footed and still it's a bit much. . I just got home from a several thousand mile drive with the 5er and the Wife was not toooo impressed LOL

 

[Todd T]

the above posts are dead on. its a much more satisfying feeling to know you have useable power than the ability to flash up high power for only a few seconds on the rollers.



But I'm with Willy on the soot. I can tow much easier than i ever could on my past 5 single charger trucks but the cost is on the take offs and the smoke. once moving it clears out. all temps are in check and i feel like i can drive forever at any speed no matter how big the hill. i no longer have to plan for hills and get a "big run" at them. or worry about getting slowed in the middle of a "big run".



In town i have to use a lite foot to get her moving or momma will use a heavy foot when we get back home and start cleaning.

 

[Fishin Guide]

Todd T,



What turbo, fueling combination are you running?



Dave

 

[BradyWilliams]

RE: Twins vs Single

Twins do have their virtues and what you say is mostly true. But a lot of the big chargers that are available have not done their home work on the exhaust side. Therefore, you may be comparing exhaust temps for BIG singles from past experience. I have towed a VERY large boat up some very long and some very steep mountains now. I have not seen HOT egt's as you have talked about. You can over whelm any engine with fuel no matter what turbo system you have. Since drive pressure goes hand in hand with egt's (more means higher) I think my next project will be measuring both egt's and drive pressure (twins and PS super 66) similar trucks and fueling. The Phat Shaft Super 66 runs a very low drive pressure. There is no way that twins can compete with a single when it comes to drive pressure. (If it's done right) Thanks

 

[Diesel Freak]

what about charge air density vs. drive pressure?



Twin's got singles beat HANDS DOWN!!!

 

[Diesel Freak]

Brett, I gotta ask... . what is your background?



Education, and experience.

 

[Fishin Guide]

Twins do have their virtues and what you say is mostly true. But a lot of the big chargers that are available have not done their home work on the exhaust side. Therefore, you may be comparing exhaust temps for BIG singles from past experience. I have towed a VERY large boat up some very long and some very steep mountains now. I have not seen HOT egt's as you have talked about. You can over whelm any engine with fuel no matter what turbo system you have. Since drive pressure goes hand in hand with egt's (more means higher) I think my next project will be measuring both egt's and drive pressure (twins and PS super 66) similar trucks and fueling. The Phat Shaft Super 66 runs a very low drive pressure. There is no way that twins can compete with a single when it comes to drive pressure. (If it's done right) Thanks

The only problem I have with that statement is that I have been asking for information just like what you are throwing out there. You have never given solid numbers for drive pressure vs boost, Charge air density, inlet temperature vs. boosted temps, ect.



If you want to be taken seriously with these comments, I would hope you, the vendor would at least have some basic info other than it spools really quick and works great.



How about some technical data to support your claims? I have asked for various specs on your SP66s and have gotten no information in return.



BTW, I would be very surprised if a large single on my truck would work nearly as well as a set of twins that I can spool much more easily. Reason is, I have that tight auto and those tall gears. There's more to the story than pulling a boat up a hill and saying that it runs great. We know twins work. The jury is out on the feel good big singles.



Dave

 

[Hohn]

We know twins work. The jury is out on the feel good big singles.



Dave

BINGO! I have to ask that if singles are so beneficial, why are more and more OEMs looking at compounded twin chargers?



Seen the new ACERT Cat Engines?



How about the Borg-Warner paper that Diesel Freak posted earlier?



Also, in a sense, it's somewhat contradictory to say that most larger singles have the exhaust side down wrong, THEN turn around and say that twins have higher drive pressure (obviously, many twins setups use the same chargers with the supposedly wrong exhaust sides!).



The real proof of this would be running a PS66 in as small charger in a twins setup. Then would could see how the superior hot side of the PS66 would enable twins to continue outperforming singles.



The design advantages of a properly designed compound setup are undeniable. The key there is "properly designed". Because a proper compound setup DRASTICALLY reduces the operating envelope each turbo is required to supply, each can be designed to be more efficient within the operating range that it IS required to meet.



We all know that there's no free lunch in turbo wheel design. You can give a wheel a really high pressure ratio, but then you end up with a narrow, flame-shaped map. You make the map wider, and then you get the air too hot at higher PRs.



I'm pretty confident that given access all the turbo maps that Garrett or T-netics have (and a spreadsheet and some other calculations), one could EASILY select two turbos that (when compounded) will provide 50psi of boost pressure with UNMATCHED air density, low temps, and breadth of operating envelope relative to ANY non-vgt single charger.





Just my amateur opinion

 

[Diesel Freak]

yee haa.



time for some popcorn... this is goona be good!!!!!

 

[Fishin Guide]

:-laf Aww c'mon Cliff,



pessimism doesn't suit you well. To date, the best information I have gotten from any vendor regarding compounds is clearly BD.



With good testing, data to back up claims and customers who reinforce what they say and in some cases, exceed the manufactures claims says alot.



I honestly think that some of us could design turbos and market them with the same success as some of these operations. Very few seem to have done any controlled testing with only a very little real world testing.



I would love to hear more how a big single is better than compounds in my appliation.



Still waiting.....



Nothing yet?



:-laf



Dave

 

[Diesel Freak]

well, while we are at it... lets throw another factor into the mix.



Dyno Type!!!!



would one use a 2500# inertia, a 5000# inertia, a 7000# inertia...



or an eddy current dyno set to for 10K, 15K or 20K



I wonder how the comparrison would go with two identically fueled 500 HP trucks on an eddy current dyno set for 15K and a 6% grade? One with one of the "self proclaimed answer to our prayers" singles, and the other with a "tuned" and "ballanced" non-hilljack engineered set of twins.



Obviously we would want to datalog coolant temp, boost pressure, EGT, drive pressure, pre CAC boost temp, post CAC boost temp.



Then once that "short" dyno run was complete, load each one contuinuously for 5 minutes at a mild 400 HP output while datalogging all the previous parameters.



I bet that would answer all of our questions!!!

 

[Hohn]

Exactly.



The fact that BD only rates their twins at 500hp says a lot about BD, and even more about the "other" twins guys.



Dyno hp may fail to be sustainable in actual usage.



Just for fun, wouldn't it be cool to have a dyno cell where you could change the weather in the cell? You want a dry 115°? NO prob-- dial it up. You want a Soggy, miserable 90° and 90% humidity? DONE! Finally, for the creme de la creme, you could CHANGE ATMOSPHERIC PRESSURE. That's right-- a dyno that can make your truck think it's pulling a grade at 8K elevation-- and climbing!



Back to twins, though. My limited experience on this leads me to believe that "dyno hp" and "sustainable hp" are worlds apart. Just as an example, I'll mention the contrasts between when I dynoed on a DJ248C (intertial) and a Superflow eddy current dyno.



On the DJ, I hit 390hp, 918 lb-ft, "corrected" (yeah right) with just DD2s and an EZ. EGT never passed 1300.



On the superflow, I hit 349. 9hp, 908lb-ft "corrected" (again, whatever), with the same combo. However-- EGTs were SCREAMING-- they hit every bit of 1550 and then some.



So while I was putting down the close to the same power, the EGTs tell the story. I could sustain the dynojet hp all day long. On the Superflow, though, anything more than just a short moment would be guaranteed meltdown. Yet, the SF measure LESS hp!!!



Maybe we should update that old saying to say something to the effect of: "Dynos lie, and liars dyno. " Uh oh-- here come the flames!



All this just to say that it's not so much the dyno that is at fault-- it's our incorrect assumption that the dyno reflects the sustainable HP you have at the wheels.



There's a reason that Top Fuel cars have 7000+hp, while endurance racing cars rarely have more than 700 or so. Why? Because A Top Fuel engine is a controlled, slow-motion disintegration/detonation. The engine is practically spent after every run. Similarly, NASCAR engines built for qualifying are different than those built for the actual race (when allowed), because the HP/endurance needs are different.



Now, we bring this full circle and see that the amount of useable HP you can build into the engine is inversely related to the amount of HP you intend to use. In other words, the guy who runs empty all the time can build in a lot more HP than can the guy who tows every day. Less still for the guy who tows HEAVY all the time.



When you talk about sustaining a certain output of HP, the allowable limit goes down quite a bit. Heck, if you could sustain 600hp out of a 5. 9, why would Cummins bother with ISXs?



The truth is that it's pretty easy to build a 5. 9 to easily tow any legal weight up any paved road in America at any legal speed. Doing that indefinitely is a different story.



BD rates their twins at 500hp, but I'm guessing they could support 650+ of "dyno power".



That said, technology moves on, and I would LOVE for the PS66 to raise the bar for single chargers.



But everytime a single charger raises the bar for singles, it ALSO raises the bar just that much higher for twins, to the point where singles CANNOT pass twins.



JMAO, again

 

[Morse]

I'm not into towing with my play truck, and I see statements of hp a lot on single chargers. . I was hoping we could see some real world feedback on what turbo combinations truely work well. . Not necessarily sustain peak power level, but max power for competition. .

 

[BradyWilliams]

RE: Twins or Single?

We agree with your analogy about raising the bar. WE SELL TURBOS, we love TWINS. I didn't try to trash any twins or singles. We sell twins also, but we have not went to market yet with a twin set up. We do sell turbos to people that make twins. We have Pro 52's instock, also GT 42's or how about a S400. As far as our experience goes, how about several of us with a life time of experience, factory training galore. Turbo training from the smallest of turbos to the biggest frame turbos. on engine experience, trouble shooting experience (in house and in the field), remote classes taught by Gayle Banks, factory training from Detroit Diesel, Cummins, Borg Warner, Garrett, Roto Master, RayJay etc. etc. , experience from supplying turbos to the after market for 33 years, and yes college. Whats yours? Our only goal is to offer you a TURBO that WORKS. If you love your twins I'm happy. If we can help you in any way with your twins or singles we will and by the way it doesn't always need to mean money with us you can call us for any reason. You know I helped a lot of TDR members about their VP44 injection pumps on another thread. They appreciated the info and products. GO Figure!