rustrocket Posted December 19, 2006 Share Posted December 19, 2006 Hey all. While searching for ways to increase low end on my turbo KA motor, i came across this, albeit for a diesel engine. Could i do the same thing using a smaller t25 turbo for low end attached to my holset hx35 for mid-top end? I'm aware of the heating issues...the intercooler in the picture must be testament to that. well...? Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted December 19, 2006 Share Posted December 19, 2006 search for consecutive turbochargers...I am going to be doing it... T3 or other small turbo and then HY35...you have to overcome the problem of the flow restriction of the smaller turbo with the wide RPM rang you will want. Diesels have a short power range so they don't have to worry about restriction much. With a 4k+ power range you will encounter a lot of restriction with the smaller turbo. Quote Link to comment Share on other sites More sharing options...
naviathan Posted December 19, 2006 Share Posted December 19, 2006 This has been discussed and I believe the consensus was the restriction from the smaller turbo would slow the larger turbo and limit the upper end power. Also note the forced air from the larger turbo is routed through the smaller one which would cause a bottle neck effect and restrict air flow there as well. Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted December 19, 2006 Share Posted December 19, 2006 But there is a solution to the restriction problem...you just have to think outside the box... Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted December 19, 2006 Share Posted December 19, 2006 The thing is that diesel engines running multi-stage turbos typically use them to make boost levels that would be completely insane on gasoline - some of these run well in excess of 100 psi. It seems like a single turbo would be more efficient until you get to around 40 psi of boost. Multi-stage turbo systems are mostly for reaching insane pressure levels rather than decreasing spool-up time. Quote Link to comment Share on other sites More sharing options...
naviathan Posted December 19, 2006 Share Posted December 19, 2006 There is a solution to everything, it's all in how much modding you want to do. Quote Link to comment Share on other sites More sharing options...
rustrocket Posted December 19, 2006 Author Share Posted December 19, 2006 While it appears doable, it seems almost prohibitively expensive, at least in my case. I dont think i have the skills to tune and match turbos to get the most out of the setup. Quote Link to comment Share on other sites More sharing options...
JustinOlson Posted December 19, 2006 Share Posted December 19, 2006 I completely agree. Compound turbo systems have no place on gasoline engines. Unless you are trying to run 50+psi, I dont see the point. KISS The thing is that diesel engines running multi-stage turbos typically use them to make boost levels that would be completely insane on gasoline - some of these run well in excess of 100 psi. It seems like a single turbo would be more efficient until you get to around 40 psi of boost. Multi-stage turbo systems are mostly for reaching insane pressure levels rather than decreasing spool-up time. Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted December 19, 2006 Share Posted December 19, 2006 Well if you have a Z that is going to push 25+ PSI but you want it to have some boost earlier...I think it would work great. Like TimZ has a HUGE turbo on his car and makes huge power...but it does not really spool in the reguar driving RPMs... I am designing my CTS(consective turbo system) to spool early and make decent power but when you hit 3300-3500 at WOT it opens up and goes insane on the power...bypassing the smaller turbo. That is just my thinking so that you don't have to drive a slug around when you aren't in boost. Quote Link to comment Share on other sites More sharing options...
rustrocket Posted December 19, 2006 Author Share Posted December 19, 2006 I'm expecting full spool around 3500 rpm, which come to think of it, works great. IT'll keep me out of boost below 90 mph in 5th gear, which should help the gas mileage. And if my redline is set around 7200 or so, that's a decent useable powerband. Olderthanme - i look forward to seeing your turbo system completed. Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted December 19, 2006 Share Posted December 19, 2006 Well I am thinking 3500 is a tad bit high for decent low end boost...my primary wil be set to about 10-12 PSI by 3200 or so and then the secondary will be set as high as I can tune...20-25ish PSI up near the redline... http://forums.hybridz.org/showthread.php?t=111606 1: small turbo bypass 2&3 are just wastegates... Quote Link to comment Share on other sites More sharing options...
alexideways Posted December 19, 2006 Share Posted December 19, 2006 Would'nt it be simpler to build a twin charger setup like this guy. http://www.hilmersson-racing.com/start.asp?show=ea Was also wondering, could one use the small turbo's compressed air to drive the bigger turbo? Quote Link to comment Share on other sites More sharing options...
onephatz Posted December 19, 2006 Share Posted December 19, 2006 the only way to get your low end spool and your high end power is to do as toyota and mazda did on their late model sports cars. have all the exhaust run to one turbo till it maxes out then a exhaust gate opens and allows exhaust to the other turbo of equal size. the two turbos combined should allow for the upper limit of what you want in top end. Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted December 20, 2006 Share Posted December 20, 2006 That is basically what I am doing with my design onephatz... Quote Link to comment Share on other sites More sharing options...
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