warrenp Posted January 8, 2007 Share Posted January 8, 2007 whats better and why compound turbo's or twins?? i realize you could probably compound a set of twins for 4 separate turbo's i ask because this is the best place for info i know of. sorry this is not z related. but this set up would be for a 5.9 I-6 cummins diesel. every one on the cummins site i go to buy the kits (compound turbos) i was thinking of cobbling ups a set of twins. what do you guys think? Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted January 8, 2007 Share Posted January 8, 2007 SEARCH!!! This has been gone over in depth at least 4 times in the last 5 weeks!!! Quote Link to comment Share on other sites More sharing options...
warrenp Posted January 8, 2007 Author Share Posted January 8, 2007 lol that would help huh? but i guess most subjects have been discussed on here at one point in time. if we all searched no one would post does it matter if it on a Gasser or diesel?? bet that hasn't been discussed Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted January 8, 2007 Share Posted January 8, 2007 http://forums.hybridz.org/showthread.php?t=111606 and it does matter...and the turbos you must use are way different in size for the size of the engine... Quote Link to comment Share on other sites More sharing options...
warrenp Posted January 8, 2007 Author Share Posted January 8, 2007 so i couldn't use for exaple 2 t3's or 2 t4's??? Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted January 8, 2007 Share Posted January 8, 2007 sigh... read the link I posted up there...all of it. you don't use two of the same turbo for a compounded/sequential turbo setup... Quote Link to comment Share on other sites More sharing options...
warrenp Posted January 8, 2007 Author Share Posted January 8, 2007 sigh... read the link I posted up there...all of it. you don't use two of the same turbo for a compounded/sequential turbo setup... no no no........ i don't want compounded set up!! yes i know what compounded turbo's are. most dodge diesel guys utilize the stock turbo and add a hx50 and up to a hx60 for home grown compound set up. see all the diesel guys are using a compound set up. but why not true twins?? never been done as far as i know.. Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted January 8, 2007 Share Posted January 8, 2007 The compounded twins is for a longer boost range so you can have quick spool with the smaller turbo and then when the smaller turbo runs out of air the bigger one is spooled and boosting even more. That way you are almost always in boost. Quote Link to comment Share on other sites More sharing options...
warrenp Posted January 8, 2007 Author Share Posted January 8, 2007 lol your a funny fella.. i know how compounds work... i know how twins work..... i understand compounds are more efficient as far was low and top end power. but why not have a set of twins? i guess just to be different. i don't really have a goal in mind. Quote Link to comment Share on other sites More sharing options...
warrenp Posted January 8, 2007 Author Share Posted January 8, 2007 i guess lets say you had 2 dodge diesel trucs. mod for mod they are the same. but one has compound turbo's and the other had true twins. i'm betting the one with compound set up would win?? but could the one with twins hold it own? would it still do ok? or would it just lag behind like it had one single turbo?? Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted January 8, 2007 Share Posted January 8, 2007 So what will twins do for you over a good set of sequentials? Quote Link to comment Share on other sites More sharing options...
warrenp Posted January 8, 2007 Author Share Posted January 8, 2007 there yah go! thats what i mean yes!! Quote Link to comment Share on other sites More sharing options...
vashonz Posted January 8, 2007 Share Posted January 8, 2007 The compounded twins is for a longer boost range so you can have quick spool with the smaller turbo and then when the smaller turbo runs out of air the bigger one is spooled and boosting even more. That way you are almost always in boost. I think what you just described was sequential turbos IE one after the other but in parallel. What I -think- warrenp is interested in is compounded IE one after the other in series. I have see this used on BIG tractor pull diesels in order to make lots and lots of boost. The 1st turbo effectively precompresses the air for the second one. Quote Link to comment Share on other sites More sharing options...
warrenp Posted January 8, 2007 Author Share Posted January 8, 2007 ohh.... i guess i have been misunderstanding? i thought compounded and sequential was the same thing. but yes i meant one after the other in series. thanks for pointing that out Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted January 8, 2007 Share Posted January 8, 2007 compounded/sequential are the same thing. You don't want to have a big turbo and a small one in parallel...bad for engine with the unequal backpressure thing. Quote Link to comment Share on other sites More sharing options...
vashonz Posted January 9, 2007 Share Posted January 9, 2007 compounded and sequential are not the same Sequential is like on the RX7 where the inlet to each turbo is from atmosphere and the outlet is to a common manifold and then to intercooler then to the engine Compounded is where the first turbo compresses to X psi, the outlet of which goes to the inlet of the second turbo, where it further compresses it from X psi to Y psi. Sorry for the big image, it does not belong to me. Back to the original question: I think compounded would make more power, if the engine were built to handle the extra boost, IE lots of fuel and propane injection or whatever they run. Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted January 9, 2007 Share Posted January 9, 2007 WOW!!! I had not thought of that layout!!! VERY INTERESTING! Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 9, 2007 Share Posted January 9, 2007 Yes, Compounded turbos ARE NOT the same as Sequential! What you get with compounded turbos is PRESSURE RATIO. About the maximum pressure ratio you can get now is around 3.5/4:1. That means you are limited to 45-50 psi output. With Sequential turbos, that's it! With compounded turbos, you get 9:1 to 16:1, meaning in theory you can get 230 psi or so from twins, but normally the practical limit is 4:1 on the first turbo, and then run 2:1 on the second for less temperature rise and easier intercooling. This will give you a useable 100-110psi to the manifold. If you want more flow, the new Garrett Turbos are spinning TWO compressor wheels (for massive flows) off ONE Turbine wheel! This makes for the flow of twin turbos, with the packaging of a single. Theri pressure ratios are in the low 4's as well. Any way you look at it, a single stage of turbo compression will be limited to around 45psi. But add a second or third stage of compression (with water injection in between stages for intercooling and efficiency) and your boost pressure go sky high, and so does the possibility for additional fuel and combustion. Tractor Pulling engines routinely have upwards of 200psi of boost! Detonation is not an issue on diesels, as fuel is not present in the combustion chamber till it's supposed to be so boost and heat is not the same issue we see in Petrol Engines... Quote Link to comment Share on other sites More sharing options...
warrenp Posted January 10, 2007 Author Share Posted January 10, 2007 where can i see these new garrett turbos??? Quote Link to comment Share on other sites More sharing options...
warrenp Posted January 14, 2007 Author Share Posted January 14, 2007 bump Quote Link to comment Share on other sites More sharing options...
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