Subaru Stratus

9 posts in this topic

Posted

A friend is trying to give some instruction to a guy with a stretched Mk 4 with a stratus Subaru in it.

They have little operating data for the motor.

Do any of you guys have any details you can share as far as rpm, temps, etc to operat this system with?

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Posted (edited)

Larry,

     Suberavid has the Stratus, and lots of experience with it - He don't get on here too often - Send him a PM to get his attention.  I think one other on here has a Stratus?

I believe 4800 is torque peak for Stratus, and max is about 5400, but Randy tells me his tach shows a lot slower - Could be in tach or something else.  

     Stratus2000 was the new company name last time I looked - Maybe they have info or phone on their site?

My non-stratus EA-81 with 1.84 ratio is supposed to turn 4200 static and unload at 4800, but Stratus has a 2.2 reduction and runs faster than mine.  Possibly, he might turn 4800 static?

EdMO

The Soob takes a 190 or 195F thermostat - If you need exact, I can look it up.  Cars don't show EGT or CHT.

note:  I JUST read that STRATUS2000 went out of business in 2008...RAM may publish some figures on theirs.

Edited by Ed In Missouri

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Posted (edited)

A vacuum gauge is nice. In a pretty much stock EA81 you are looking for about 5 inches at 4000 rpm cruise. (holley carb)This will give you 80 mph with warp drive prop at 8.5 degrees. Oil pressure should be 40psi, temp 170. Temp will go as high 190 on a hot day climb out. The rpm increase in the stratus is primarily from the s-250 cam grind. Raises the torque curve to higher rpm. Without the higher rpm cam grind you are not making more power. Flattening the pitch increases rpm but no more pull after that 4200+ static (stock). Carb balancing would be critical on the stratus with the bing carbs. To do it right you need gauges just like a 912. I'm sure the stratus makes more heat though because it is making more power. Michael Templeton in Washington bought the company and renamed it Stratus 2000. He's closed up but maybe you can track him down. I chatted with him once and he was informative and easy to talk to. 

Edited by IFMT

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Posted

I was told to set my WD prop at about 11 degrees for the 4200 static - haven't tried it - Believe Suberavid said same degrees for his?

EdMO

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Posted

When I first got it I was at 11 or so as well. Plane would easily exceed 100 mph but takeoff roll suffered. I can't remember exactly but maybe I was a little higher static at 8.5. Wide open around 4600 with 1.84 reduction. I found with the stock cam it just makes more noise and no more pull by flattening below 8 degrees. 3 blade warp drive cut down to 68 inches. I think Randy has an in flight adjustable.

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Posted (edited)

Mine has the heads milled and cam ground, sort of like Stratus - Owner said some fool before him flew it at 5700 and burned crank - Don't understand that, since Subaru ran these at WOT for 6 or 7 days, continuous, to test them in cars.

Had a Major overhaul and 75 hours since then - He told me to not exceed 5000, but 4800 better - that is highest torque.

Suberavid had a  GA WD before IFA -

EdMO

Edited by Ed In Missouri

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Posted

Was there ever a manual or published data card concerning this motor/conversion?

I'd like to find some "in writing" data in order to mark the engine instruments.

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Posted (edited)

Wide open in a car is rated at 4600 I believe. Not 5700. I don't know of an actual specific aircraft data parameter. The temps and oil pressure are derived from automotive application manual and experience. 

Edited by IFMT

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Posted (edited)

Larry,

     In the early conversion days, RFI (Rotary Flight International) did a lot of work converting them to Gyros / Choppers, and wrote about it in "Contact" magazine.   Mine are stored away somewhere.  Other than that, like IFMT said, it is in the car manuals.  I have at least 2 manuals in my cabinets.

     RFI wrote an article about Subaru testing these engines in cars driving them for days at WOT, but it has been misquoted so many times now that I would have to find the original to copy it.  I think it was about 60,000 miles for each car, and they had about 6 cars running the race track?

     RAM is doing, or was doing, these conversions, maybe if you check with them.

Suberavid said he just treats his like driving a car:  get in - turn the key - and go!

EDMO

Edited by Ed In Missouri

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