Jump to content

Welcome to Ultimate Subaru Message Board, my lurker friend!

Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.

We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!
  • Say hello and join the conversation
  • Subscribe to topics and forums to get automatic updates
  • Get your own profile and make new friends
  • Classifieds with all sorts of Subaru goodies
  • Photo hosting in our gallery
  • Meet other cool people with cool cars
Seriously, what are you waiting for? Make your life more fulfilling and join today! You and your Subaru won't regret it, we guarantee** it.

* The joy of participation and being generally awesome constitutes winning
** Not an actual guarantee, but seriously, you probably won't regret it!

Serving the Subaru Community since May 18th, 1998!

Guest Message by DevFuse

- - - - -

How hard does your EA81 rev and why.

  • Please log in to reply
5 replies to this topic

#1 Knucklehead Saloon

Knucklehead Saloon

    USMB is life!

  • Members
  • 137 posts
  • Singleton NSW Australia

Posted 14 November 2017 - 03:29 AM

I just got mine to hit 6100rpm.

Stock motor internals, stock intake manifold, stock exhaust, weber 32/36 with 140 / 155 mains, msd 4500v coil, race leads, iridium plugs, 2wd leone distributor. Advanced ignition timing till it pinged and then backed it off a bees wongleflute.
Attached File  tach10.jpg   96.35K   7 downloads

#2 DaveT


    Subaru Nut

  • Members
  • 3,627 posts
  • Colchester

Posted 14 November 2017 - 08:22 AM

That's not a surprising number. These engines are made to spin fast, not lug at low rpm.

#3 carfreak85


    Temple of Fuji

  • Members
  • 5,244 posts
  • Cascadia

Posted 14 November 2017 - 10:17 AM

I don't bother to wind mine out past the stock 5.5k redline.  The turbo kicks in at 1,500 rpm and all the power is in the middle of the rev range anyway.


If you're shifting at 6,100 rpm, you're not shifting at the right rpm for acceleration.

#4 jono


    Reader and writer

  • Members
  • 1,688 posts
  • Southern Hemisphere - AUS

Posted 15 November 2017 - 06:12 AM

I revved my first build to valve bounce and after 180,000km the crank flexed a bit too much and mushroomed the centre main bearing seat. Still went still revvedjust hhad a RUmble at revs but essentially the three mains ain't really made for revs

#5 DaveT


    Subaru Nut

  • Members
  • 3,627 posts
  • Colchester

Posted 15 November 2017 - 12:59 PM

I'll add, I am referring only to stock un modified engines, operating within their specifications, that is not above red line.

#6 subnz


    USMB is life!

  • Members
  • 241 posts
  • Glenorchy New Zealand

Posted 16 November 2017 - 12:58 AM

Not very high in standard form (EA81)


Other reasons  -  2 valves / cylinder single port intake and exhaust port heads / small shared manifolds (limitations to air flow increases for limited performance gains)

                          -  similar for EA82s


                       - OHV  limits high RPMs also


                       - Agree, 3 main bearing crank  - bottom end  not as  strong for high rpms  (EA82 similar)


IF serious about performance gains , EJ engines with 4 valves / per cylinder  bigger manifolds,   better  for air flow increases / performance gains - especially ones with 4 port heads DOHCs,      with freer revving OHCs,     better for higher rpms.

Also 5 main  bearings on crankshaft  - bottom end  stronger for higher rpms.


Wouldn't and didn't bother to try and modify my EA81 / 82s for those reasons.


The only one I would consider modifying is , if  had an RX2 AWD 5MT D/R  with EA82T  would replace heads with  4 port heads / manifolds etc  upgraded internals etc  ,do it properly.

Power gains from 115hp (stock)  up to 200hp


Also EA82 OHCs are more free revving so a better platform to start off with    than  clatterly  old school  OHV EA81s best left stock.


PS  EA81s are mid rangers  ie work best keeping motor spinning between 2500rpm  and 3500rpm  (ie max torque at 2400rpm  max hp at 4800rpm   

Nothing to be gained in exceeding 5000rpm just to prove a point apart from trying to destroy an engine .that isn't designed for high rpms.

Ea81s are bomb proof simplicity (gear driven cam) but over revving them is a sure way to try and kill them.

Edited by subnz, 17 November 2017 - 11:46 PM.

0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users