Mobius

iTrader: (2)

So

I feel I have valid contributions to this discussion, being a) a driver of a rotrex C-74 car @210whp for 5 years and b) currently a driver of a 250whp TSE EFR 6258 car.

1) You don't have to run the EFR at 300wtq. The great advantage of a turbo over the rotrex is variable boost under variable conditions. Currently I have my EBC set to give me about 200wtq from 4000-7200. When I get on it on track, it just pulls.

2) the EFR spools quickly, and the integrated recirculating BOV helps to keep it spinning off throttle. Between the two, yes the Rotrex gave crisp definitive absolutely no lag throttle response - but the EFR response is such that if you had not previously driven a Rotrexed car of a similar power level, you would say the response is not noticeable.

3) the EFR gives me torque from down there to up there. I can change that response as I wish with EBC control. I've currently limited it to 200wtq to save the trans ... I'm now thinking that's overly conservative, and will probably bump that to 230 wtq. That flexibility is another advantage of the turbo over the rotrex.

4) I enjoyed my rotrex setup. It was simple, easy, and light on heat management. I also enjoy my EFR setup. It is somewhat simple, not as easy, not nearly as light on heat management. Under hood temps are significantly hotter. Water and oil lines had to be run. But the the power flexibility and usable power potential is so much greater with a 6258 compared to a C30-74. Even a -94, really.

So here's my tl;dr. If you want ultimate easy boosted reliability, go rotrex. If you want boosted reliability with flexible power management, with a vastly greater torque band, but with corresponding increases in needs to deal with heat rejection, go TSE 6258. Other turbo kits have no place in this discussion, really, as they were not originally designed for track use. Apples to oranges.

I 100% do not regret moving from C30-74 to TSE EFR 6258. But, I will also say that I enjoyed the **** out of my C30-74 and the simplicity of its installation.

Braineack

iTrader: (62)

Coincidentally, this does not change for a belt driven turbo either.

there's some appeal here, but everything you've listed at this point is a non-issue and not mutually exclusive to a turbo.

I drove fast on the track with my turbo and lived to tell the tale.

again: the only thing I was commenting on was "too much tq" with a turbo. If you have "too much tq" then make it not.

18psi

iTrader: (76)

It's always so amusing to see how hard people will continue to repeat silly statements to justify their bad or unpopular decisions. Tell yourself whatever makes you sleep better at night =, but at the end of the day if you were right this place would be called miatarotrex.net or at least have enough rotrex Miata's to justify having a subsection for em.

Meanwhile we're enjoying torque

Nailed it. prop cat deserved

Goingnowherefast

iTrader: (1)

I think Mobius hit the nail on the head. There's merit to both setups. If I had unlimited money and a trailer it would be TSE EFR all the way.

18psi

iTrader: (76)

rotrex Miata is still infinitely better than n/a Miata so...

Goingnowherefast

iTrader: (1)

Now that we can agree on.

poormxdad

I also enjoy the **** out of my Kraftwerks C30-74 kit. I went Rotrex three years ago because I got the complete kit, new, shipped, tax free for $3000 as an Indiegogo perk for donating to a Skunk2 effort. I couldn't resist. I have had zero Rotrex-related issues. None, after more than three dozen track days and more than 17,000 miles. And, as 18psi said, it's infinitely better than an n/a Miata. A 211hp/170tq Miata is a surprise to a lot of people.

Braineack

iTrader: (62)

hey we all agree!

Savington

iTrader: (31)

You have your preference for a Rotrex, which is fine, but their **** hardly smells like roses. Belt and tensioner issues are a relatively common S/C problem that few people like to talk about. They also can suffer from broken supercharger brackets, completely separate oiling system filled with extremely expensive oil that must be configured in a specific way, and extremely expensive replacement units if required are all things that can be issues with Rotrex issues.

From your list of "issues" with turbocharger setups, five of your six items* are easily solvable with off-the-shelf parts (studs, good manifold, good radiator+ducting, good IC, and an EFR IWG or any turbo with an EWG). All of those issues are a result of people being cheapskates when trying to put a track car together. If you buy cheap ****, cheap **** breaks. There is no "cheap ****" Rotrex kit. No eBay bracket, no knockoff supercharger, no shitty off-brand tensioners. If you buy a Rotrex, you're getting nice stuff, and it all works. If you buy a nice turbo kit (like mine), it all works. There are half a dozen dedicated race cars built in the last 6 months using my kit, and all of them work. Probably another dozen guys using the kit in road/HPDE configurations, all of those work too. None of them suffer from the supposed cornucopia of issues you've laid out.

Rotrexes are easy to drive in part because they have great response, and in part because they make much, much less torque than a turbocharged car with the same peak output. If you tune an EFR car to run the same as a Rotrex, it would be (nearly) just as easy to drive. The driveability is not inherent to the FI solution, it's inherent to the powerband. If you have a big, high-power Rotrex car, it will arguably be HARDER to drive than a high-power EFR car, since the Rotrex's throttle will be incredibly touchy (boost based on RPM and nothing else, for better or for worse), whereas the turbo can be tuned to use a TPS sensor to alter boost levels and deliver less boost at lower throttle positions (more driveable). The saving grace is that, again, a high-power Rotrex car makes way less torque than a high-power turbo car.

Rotrexes are generally easier to get set up because they make less power. Period. Look at the dyno chart for any Rotrex setup and compare it to a chart of a turbo car making the same power and you'll see what I mean. If you make power, you create heat. Rotrexes create less power, so they create less heat. Because of the high average power output of a turbo car, heat management can be difficult, but again, there are known strategies for dealing with those heat issues that are easily implementable for the average enthusiast. Aluminum heat shields, reflective heat wraps, firesleeve, etc. is all inexpensive and effective.

So yes, Rotrex kits have their appeal in simplicity and reliability, but so do good turbo kits. It comes down to response vs powerband and which is more important to you. I have driven good Rotrex cars, I know what they are capable of, and they are the right solution for some people, but a good turbo kit is far, far, far better than you make it out to be.

(* - The sixth (higher oil pressure) is just not a thing, at all, so I'll ignore it entirely and assume you made a typo or something. As in, turbos don't substantially alter oil pressure in any way, and even if they did, raising it would not be a bad thing within reason, but they don't, so it's not, so ????)

Braineack

iTrader: (62)

well put.

bschonman

You guys are starting to sell me on an EFR, although it'll likely be years from now.