Hello Tikie. I have about 300 hours in N133RM so I can speak a little about running a VW (Revmaster) engine with a turbo in a KR2S.
* If you are trying to gain maximum benefit for all operations and altitudes with a turbo, yes you would need a controllable pitch prop. That would add a lot of weight , complexity and cost to the airplane. * If you are trying to gain high altitude performance, yes a turbo will offer that new capability with a standard fixed pitch prop. Run the engine in what is called “turbo-normalized” mode to gain manifold pressure at higher altitudes to gain more power. As Larry pointed out below, oil and cylinder cooling are areas where you need to pay extra attention. Running a turbo at lower altitudes requires carefully watching effective boost to avoid accidentally overstressing the engine. When N133RM was built, the owner added a simple metal clip on the throttle control that limits boost to about 36” manifold pressure. About 5000 feet you can remove it and take advantage where the turbonormalized operation really cranks up your speed. Further, turbo engines are designed to run at lower compression ratios to avoid detonation so things like cylinder head volume and deck height are calculated during the engine build process. Just adding a turbo on a normally aspirated engine can … lead to issues. I hope this helps add to information about your decision making process. Cheers. John Bouyea / OR81/ Hillsboro, OR N133RM KR-2S – imported, fixed & flying www.bouyea.net/N133RM From: KRnet [mailto:[email protected]] On Behalf Of Larry Flesner via KRnet Sent: Sunday, August 10, 2025 1:54 PM To: [email protected] Cc: Larry Flesner Subject: Re: KRnet> 2L VW/ Turbo Tiekie, Not sure what Paul meant by "a constant speed" but it sounds like you are unhappy with the performance of the KR (too little power). Options: 1. Install a bigger engine 2. Reduce the weight of the airplane. Probably not an option. 3. Turbo the one installed. Concerns: Over heating and / or over-stressing the engine to failure Fixes: Install an oil cooler or a second oil cooler if you already have one. Install a plenum for better cylinder cooling or otherwise modify the cowl. You would also want a positive "boost" control so you don't over-boost. The boost is most effective at full throttle and/or altitude as below full throttle setting you can control engine output with throttle setting and at altitude where you can keep the manifold pressure at "sea level" or greater for maximum output. There is no such thing as a free lunch. Calculate the cost and effort of each option and see which one wins. Of course, the cheapest option is to fly it as it is. Larry Flesner ================================================================================================== On 8/10/2025 3:19 PM, Paul V via KRnet wrote: I have heard that tp benefit from a turbo you would need to have a constant speed. Because your max RPMs don’t change you’re still limited on RPM. Paul Sent from my iPhone ====================================================================================================== On Aug 10, 2025, at 1:36 PM, tiekie bernardus via KRnet <mailto:[email protected]> <[email protected]> wrote: Hi Everyone. Im thinking to install a turbo in my latest KR2 that i have completed. Im very hesitant to do that, as im sure i will run into oil cooling problems as the engine have to work harder therefore more heat is generated. Any advice would be appreciated whether to go that root or not. Im sure in the long run i will run into problems with the engine. Best Regards Tiekie Get Outlook for iOS <https://aka.ms/o0ukef> -- KRnet mailing list [email protected] https://list.krnet.org/mailman/listinfo/krnet
-- KRnet mailing list [email protected] https://list.krnet.org/mailman/listinfo/krnet
