aidandj

iTrader: (5)

My low boost setting is less than 150ft/lbs of torque. EWG or a really low boost actuator does the same thing but lets you do more.

wannafbody

iTrader: (1)

I own a water cooled twin turbo F150 that was designed for durability and torture tested and despite that there have been some turbo failures. I'm not convinced that non water cooled turbos in a race track environment are gonna last. What's the average lifespan in miles? 10K, 20K 30K? Anyone know?

aidandj

iTrader: (5)

Why would you use non watercooled turbo? That would reduce the life.

Whats the lifespan of a rotrex?

wannafbody

iTrader: (1)

I wasn't aware that the turbos Miata guys are using are water cooled.

aidandj

iTrader: (5)

You do realize there is more than 1 turbo in this world.

Joe Perez

iTrader: (8)

I'd say that the split is probably somewhere around 60% WC / 40% non-WC, or something around that. Maybe slightly higher numbers for WC, as my own observations are likely skewed towards the cheapskate side of the community.


A lot of folks are still running old Greddy kits which came with non-WC Mitsu turbos, and a lot of folks buy cheap Chinese-made turbos, many (most?) of which seem to also be non-WC.

What I'll call the "mainstream" Miata turbo packages mostly use Garrett 25/28-series turbos, which are all water-cooled. And more recently, the "all of it" crowd have been discovering the BorgWarner EFR series, which are also water-cooled.


And there are yet other "minority" turbos out there as well from manufacturers like IHI, Holset, etc. Again, some WC, some not. There's even one (can't recall who makes it) which comes with a "permanently greased" center section. Weird.

You see about the same split phenomenon in the sleeve-bearing vs. ball-bearing decision.

wannafbody

iTrader: (1)

thanks

18psi

iTrader: (76)

You realize that water cooling really just does what it needs to do when you shut the car off hot right?
So this discussion is dumb, and you should learn how turbo's work.

Joe Perez

iTrader: (8)

I've been trying to find some good photos of a current-gen F1 turbocharger. Not coming up with much.


Regardless... My point wasn't "turbocharger is better than supercharger" per se. Positive-displacement superchargers still have a large and loyal following, and I can understand why; they have no boost threshold, no spoolup time, and can produce maximum PR right off idle. So for a drag-racer, or someone who spends their whole life below 4,000 RPM, I can totally see the appeal.

I just don't understand centrifugals. They produce the least-flat torque curve of anything, and don't offer any advantage which I can perceive over any alternative form of forced induction. Regardless of whether you're on the street or the tack, I just can't see why you'd want to only ever be able to produce peak torque at peak RPM. That concept does not positively correlate with the maximization of either fun or reliability.

18psi

iTrader: (76)

Maybe I'm misunderstanding, but what do you mean maximum PR right off idle?
My MP62, and most others I've seen only build 3-4 psi and then slowly taper up to 10 or so at redline in both the cold side and hot side variation. The 45s offer even less.

The really big ones produce way more from the get go, but this is not the case with the 46 or 62. Though even that much is still enough to make a healthy improvement in low end, of course.

wannafbody

iTrader: (1)

I was under the impression that the water cooling prevents coking of oil in the turbo. Isn't that a good feature?

patsmx5

iTrader: (16)

Yes, my Whipple will make more and more boost as you rev it. The SC lets air leak past the rotors/screws, so at low RPM since they spin slower, more air leaks back so less boost. With more RPM, the SC becomes more efficient. Also, at high RPMs, the motor's VE drops but the SC's doesn't drop hardly any, so again, boost builds because of this.

My setup makes 22 PSI at 8,000, 5 PSI at 2,000, 12 PSI at 3,000. Those are the only numbers I know off the top of my head.

18psi

iTrader: (76)

Correct, but when the oil is moving, it's not gonna bake on, it spends almost no time inside the turbo before draining back.
It's when you shut the car off and the oil is no longer being pressurized through the chra that you need the water to cool the chra off as fast as possible to prevent what you're talking about.

Operation is kinda like of the oem "oil cooler" which is really a heater.
Yep that's what I've observed. Yours is a relatively big charger too, compared to the normal ones used on miata's.

patsmx5

iTrader: (16)

Why not.

Savington

iTrader: (31)

CF blowers can be intercooled without altering throttled volume, unlike most PD blower setups. The only way to do that with a PD setup is a dual-throttle hotside blower, and nobody offers that in an off-the-shelf solution.

The rising torque with RPM makes the car easier to manage on track, and the lower average power output results in less strain on the cooling system.

I think turbos are better, but I can absolutely see why CF blowers are popular, and for some people, they are the right solution.

Mobius

iTrader: (2)

More power makes more heat, but with the SC that heat is mostly sent on out through the exhaust, where with the turbo it is contained and made to do work inside the engine bay. There is significantly more heat in the engine bay with the turbo because of this. Engine bay heat management is a non-issue with the Rotrex.

The some people are people who:
* want some more power
* want to keep reliability
* want ease of installation & maintenance
* the absolutely predictable torque delivery is better for novices, and preferred by some advanced drivers.


What Aidan is lacking is the 8-10 years of watching various forced induction track pioneers on this board blazing a laborious trail towards trackdaybro reliability. It didn't just happen.

Akuma R

So back on topic. I talked to JR at MRLS this year and they said they were having overheating issues with the kit. So they developed a 2 in one radiator/oilcooler, where the cooler is built into the rad as a single unit. I believe it was an oil cooler.... anywho cant remember exactly what the rep said about the release date, just my .02

Alternative

That doesnt sound correct being that the maximum operating temperature of the rotrex is well below engine coolant temperatures.

aidandj

iTrader: (5)

From what I've read i believe its an engine oil cooler.

Chilicharger665

iTrader: (2)

CSF is making a custom radiator with an oil cooler in it exclusively for Jackson Racing for NA's and NB's.

CSF announces The "O" Series - CSF Racing

They have an MSRP of $650 for the Subaru STI versions, but it says the Miata version should already be out, but just like everything else that deals with Jackson Racing... it is late to the show.

I have no idea what they plan to supply to get the oil to the radiator in the first place.