In reply to Rodan :
Yeah, when I called Berg Racing, who did the tuning, they asked for the details, and said that it should make 190-200hp. I know that their dyno tends to read low, but that seemed a little disappointing, considering that Track Dog said it was good for 240hp. Then, after they cleaned up the map enough to start making pulls, it made 216 on the first pull at around 6000rpm. And then it just kept going up. Good to see that it made exactly what TDR said it would
Rodan said:Nice!
Most Rotrex results have seemed a little disappointing, but that's very impressive. Congratulations!
Maybe that's because it requires or benefits more from those breathing mods up top?
Interested to see the dyno curve. Is rotrex pretty much the only supercharger that is getting used for track day like stuff now? The other style ones have more torque lower but less power with rpm?
Most of the positive displacement blowers will heatsoak on track, so you don't see them much except for AutoX, and casual HPDE cars. The Rotrex gives a really nice linear power curve, which makes it great for a track car.
I was seriously interested when the kits first started getting developed, but folks were having issues with cracking brackets and slipping belts, and the vendors seemed like they weren't very committed to the kits. Dyno results for the vendor cars were great, but the customers weren't duplicating the results. The TDR kit that Nick has is, I think, the only one still on the market...
There are a few guys that have gotten them to make good power and be reliable. It looks like Nick's is going to be one of those, and I'm glad to see him get good results!
I know one of my buddies in Socal built his own off a Kraftwerks kit and was not really pleased but he is a fan of the TDR build quality.
I just keep wondering where is the best way to spend that 6kish for the FI and supporting mods. Trackspeed still doesn't sell a soup to nuts complete EFR kit, FM does/did, TDR has the rotrex
Jaynen said:I just keep wondering where is the best way to spend that 6kish for the FI and supporting mods. Trackspeed still doesn't sell a soup to nuts complete EFR kit, FM does/did, TDR has the rotrex
It really depends on your goals... the Rotrex is a great solution for simplicity if your goal is 200-250hp, though there have been mixed results. If you're building a turbo track car, Trackspeed's EFR kit is really the only solution if you want it to be bulletproof at 300+hp. As noted, it's still an a la carte solution, and I don't think that's really going to change given it's designed as a race setup. For a street car that sees the occasional HPDE day, FM2 is still a solid choice, though the MKTurbo kit is a darn good value for a street car.
If I decide to go turbo on our track NA, it will be the Trackspeed setup. Buy the manifold, turbo and intercooler from Andrew and fab everything else from scratch. For a street car, I'd go MKTurbo at this point.
In reply to NickD :
That's a great looking graph... and that's why the Rotrex is so nice on the track. It wouldn't be any more linear if you used a ruler to draw it! 
Yeah, it is a textbook example of a linear power curve. On the street, below 3500rpm it feels like an NB with maybe a little more kick. Then it takes off like a rocket ship and just keeps pouring on the coals. I broke the tires loose in the rain from a roll at the top of 2nd gear, which completely caught me off guard. And when you are cruising, it is completely unobtrusive.
I originally looked heavy into Eaton blowers because I wanted some low-end punch, but I saw a few issues there. A) There aren't many new kits except for the Fast Forward kits (the pricey ones with the goofy fifth injector) so you are getting into used secondhand stuff that is often in need of overhaul or missing parts. B) The numbers for a lot of them just weren't that great. C) Heat-soak. Talked to the owner of a Jackson-blown Miata and he said on a dyno, the first pull was stout, second pull was down from the first, third pull was stock N/A power levels. I was still considering them, due to the fact that they are typically cheaper and I could use the money saved to vent the hood and run a meth/water injection system, but the mutt nature of my engine swap caused some confusion on what I exactly needed, and there doesn't seem to be much knowledge.
I also considered a turbocharger kit. Problem was, at the time, it seemed like some of FM's components were constantly backordered and I didn't want a CXRacing (or similar) chinacharger kit.. I also didn't like how a turbo adds extra coolant and oil lines that are potential sources of failure (as the magazine's turbo Miata has demonstrated) and I also don't like that it shares oil supply with the engine. In the event of a turbo failure it contaminates your engine oil, and vice versa. Not a fan. Turbochargers also seem kind of fiddly in general.
I settled on the TDR Rotrex kit after a suggestion from Jaynen and doing some reading, and remembering an article where Hot Rod delved into the Rotrex. I liked that it was a fully comprehensive kit that addressed everything (like ducting for the traction fluid cooler) and that they had spent 2+ years developing the kit before releasing it on the public. Also, you can't just go on their website and order a kit, you call them and they ask you questions and take your info and configure the kit to your car. For example, I told them I had a Koyo radiator and they gave me the heads-up that it doesn't work with their charge piping due to Koyo's extra-tall top tank. And when I informed them that I was running Megasquirt, they swapped up to 700cc injectors and sent me a charge pipe with an IAT bung and a MAF delete. The customer service was just absolutely phenomenal.
Also, swaying my choice a little: the kit looks super bitchin' when installed, with the laid-back radiator and charge piping over the radiator and new close-out panels. And I have seen numerous turbo kits, Jackson blowers and every engine swap under the sun in person, but I have never seen a TDR Rotrex Miata in person ever.
The only downsides are A) price. Not a cheap kit. B) Rotrex superchargers don't sound particularly cool. At idle they sound like a broken A/C compressor and under power they don't have the cool whine of an Eaton. But that's a really minor complaint
So, stock style pistons? How stock?
white_fly said:So, stock style pistons? How stock?
Design and compression, I'm sure. I think they may be stock material as well. Not sure. They aren't in production anymore. The machine shop that did all the machine work on the engine had them sitting on a shelf for at least a decade, and when he saw that it needed an overbore (rust in the #1 cylinder) he punched it out to that size and gave me the pistons and rings and bearings for free.
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