GregM Posted April 11, 2022 Share Posted April 11, 2022 (edited) My yellow "DSK 13B" has finally showed up. Lots to explore but everything works and looks solid and well put together. Needs a good detail and a bit of TLC. I am still talking with David Kaplan, DSK founder, about this car since, per him, the car has not been assembled by DSK. I am being told however that the chassis is the last chassis DSK has sold which is what I am trying to verify. Anyway, besides its origin and history, this car has a Mazda 13b rotary engine which should make things more interesting. More to come! Edited April 11, 2022 by GregM Link to comment Share on other sites More sharing options...
MV8 Posted April 11, 2022 Share Posted April 11, 2022 Nice score with some minor/fun fixes but clean otherwise. I don't see an oil injection tank so you will probably need to mix it yourself or retrofit an injection system but I've no experience with that. I think oem apex seals when treated well can last about 80k without excessive smoking. Something to look for is the internal chrome plating can be damaged and require replating. These are known to be very loud so for road use, you might consider shelving the race exhaust and make/have made a quiet system in stainless or have it ceramic powder coated using an oem application 6-7 inch round muffler and a transverse oval or resonator/glass pack under the trunk/spare. I can post a pic of a list I recently put together of oem replacement walker mufflers and resonators that could be suitable if you are interested in the option later. Link to comment Share on other sites More sharing options...
GregM Posted April 11, 2022 Author Share Posted April 11, 2022 You are possibly right regarding the need to run on premix. The engine is not very loud as it goes through 3 different mufflers (2 pre-mufflers then a supertrap) besides, I like it a bit on the loud side. Link to comment Share on other sites More sharing options...
MV8 Posted April 11, 2022 Share Posted April 11, 2022 Good to know. Sounds like it runs well. Does the exhaust loop up over the axle or run straight back under the car? I've seen donkervoorts loop over. Some handy info on premix/oil injection: https://rotaryperformance.com/blogs/news/84479876-to-premix-or-not-to-premix It sounds like a pre-88 refurbished mechanical system would be the most practical. 1 Link to comment Share on other sites More sharing options...
fastg Posted April 11, 2022 Share Posted April 11, 2022 It looks very well put together, all neat and tidy, just needs a good clean. It that twin alternator belts, if so a little strange. Getting a airbox with cold air would help a lot, just sucking air from under the bonnet is never good. Supertrap exhausts suck, they may reduce sound but the kill performance. I had a Supertrap on the first Honda setup to reduce the ear splitting sounds levels. The dyno operator said that has to go, we removed it for the final dyno runs and picked up 25BHP. Graham 1 Link to comment Share on other sites More sharing options...
GregM Posted April 11, 2022 Author Share Posted April 11, 2022 (edited) Yeah I will most likely experiment with the exhaust. Not only I'm not completely sold to the Supertrap idea but the entire exhaust system on this car is over complicated and heavy. Yes, it does loop above the rear axle. All that might not be unique but it goes against the "light is right" motto. For the intake, right now, I need to find a new filter. Not sure what air cleaner this is but the carburetor is a Mikuni 44PHH. First on my to do list, after a good clean, is to sort the wiring harness. Everything works but some wires seem to have been added after the fact and will cause electrical gremlins as soon as humidity shows up. Edited April 11, 2022 by GregM Link to comment Share on other sites More sharing options...
fastg Posted April 11, 2022 Share Posted April 11, 2022 One issue with Rotary engines is VERY high exhaust temps, so it will take carful design, and maybe why the current setup looks a little overbuilt. Graham Link to comment Share on other sites More sharing options...
GregM Posted April 11, 2022 Author Share Posted April 11, 2022 If that is the case, isn't it better to release them away as soon as possible instead of heating up 3 mufflers and 15 feet of pipe? Link to comment Share on other sites More sharing options...
GregM Posted April 11, 2022 Author Share Posted April 11, 2022 Link to comment Share on other sites More sharing options...
SENC Posted April 11, 2022 Share Posted April 11, 2022 Looks and sounds great, well bought! 1 Link to comment Share on other sites More sharing options...
MV8 Posted April 11, 2022 Share Posted April 11, 2022 4 hours ago, GregM said: For the intake, right now, I need to find a new filter. Not sure what air cleaner this is but the carburetor is a Mikuni 44PHH. Looks like a KNN e-3341 filter from a 56-1350 assembly, fitting Weber DCOEs. Overall assembly dims 4.5 x 7 or 5.5 x 9? Link to comment Share on other sites More sharing options...
GregM Posted April 12, 2022 Author Share Posted April 12, 2022 3 hours ago, MV8 said: Looks like a KNN e-3341 filter from a 56-1350 assembly, fitting Weber DCOEs. Overall assembly dims 4.5 x 7 or 5.5 x 9? The filter itself is 4.5 x 7 by 4 inches tall. I initially looked into that e-3341 but it turned out that it needed an e-3954. The difference is one being an oval, the other a rectangle which is what I need. Thanks for the suggestion though. https://www.jegs.com/i/K-N/599/E-3954/10002/ Link to comment Share on other sites More sharing options...
GregM Posted April 12, 2022 Author Share Posted April 12, 2022 Maybe one of you guys know: the oil filler neck on that 13b engine has a small port at its base and it’s currently not connected to anything (left open to the engine bay) which doesn’t look right. What is this supposed to connect to on the rx-7 ? I’m thinking PCV valve but since it’s a rotary, it’s obviously different. Oil catch can? Link to comment Share on other sites More sharing options...
MV8 Posted April 12, 2022 Share Posted April 12, 2022 It is a crankcase port like a valve cover. Could go to an inline pcv or a can/breather filter. Link to comment Share on other sites More sharing options...
GregM Posted April 12, 2022 Author Share Posted April 12, 2022 Yeah, that's what I thought. It's definitely missing. It should be a quick fix. Thanks. Link to comment Share on other sites More sharing options...
GregM Posted April 14, 2022 Author Share Posted April 14, 2022 (edited) The builder is believed to be Bill Giltzow from NJ. Edited April 16, 2022 by GregM 1 Link to comment Share on other sites More sharing options...
Croc Posted April 14, 2022 Share Posted April 14, 2022 Thats great news! 1 Link to comment Share on other sites More sharing options...
GregM Posted April 14, 2022 Author Share Posted April 14, 2022 Some interesting documentation that came with the car. Link to comment Share on other sites More sharing options...
7Westfield Posted April 17, 2022 Share Posted April 17, 2022 (edited) Looks like fun YEARS ago, I put a 13b in a Lotus 51, made one hell of an autocrosser Don't run it without figuring out the oil situation, or at least dumping some in the tank for insurance. I left the stock mech system on mine, never had a problem, it just uses crankcase oil. Edited May 5, 2022 by 7Westfield typo 1 Link to comment Share on other sites More sharing options...
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