EA81 - tacho said 6000 rpm !!

steptoe · Post by **steptoe** » Wed Mar 16, 2016 7:12 am

My goodness - I know Willys five speed FWD box has a different ratio for each cog compared to the 4 sp 4WD box in my Brumby ... I had my eye on my new SAAS in cluster tacho last night and saw it just nudge six grand in second gear and suspect it was near 90 kph. I'm not planning on doing it again. Willy hits 100 kph + in his EA81 second gear - must be near 7000rpm ?

My tune is a bit on the lean idle side of things and cannot just put the boot into it - have to sort of feed it to get it out of the lean circuit then stomp it

Also got to take it up a steep incline in 1st 4WD HI , light throttle and it willingly ate up the hand size rocky stretch in comfort .

Pretty happy I was not moved to sell my twins. This was with a standard diameter exhaust

Post by **TOONGA** » Wed Mar 16, 2016 8:48 pm

The EA81 is very hard to destroy 6000 rpm is 500 rpm from the 5500rpm beginning of the red line.

here is an analogue dash with the red line showing.

stolen from here

showthread.php?t=22655

TOONGA

Willy Fisterbottom · Post by **Willy Fisterbottom** » Thu Mar 17, 2016 8:39 am

Yes, 7000 rpm in the EA81 Brumby in 2nd at at 100kmh, same in the Carb EA82 L series as seen in that facebook pic.

Phizinza · Post by **Phizinza** » Thu Mar 17, 2016 7:50 pm

I hit 8300rpm in my old dual carb ea81 a couple of times. I did end up replacing a few broken valve springs before it was bought by SilverBullet. No lasting harm was done

Silverbullet · Post by **Silverbullet** » Thu Mar 17, 2016 7:58 pm

Phizinza wrote:I hit 8300rpm in my old dual carb ea81 a couple of times. I did end up replacing a few broken valve springs before it was bought by SilverBullet. No lasting harm was done

Good thing the 6 gauge cluster tacho goes up to 8,000 then

Might have to program a rev limit into the Megajolt for safety reasons

YouTube · Post by **El_Freddo** » Thu Mar 17, 2016 11:42 pm

Pfft... "Safety reasons"!! You mean "LEAD FOOT reasons"??

Cheers

Bennie

Post by **Bantum** » Fri Mar 18, 2016 3:40 am

Silverbullet wrote:Good thing the 6 gauge cluster tacho goes up to 8,000 then

Rarely seen it go past 6000 in the Auto Touring Wagon ( probably governed ), but I have maxed out the Brumby going down the straight at Hidden Valley, NT ... Not sure what RPM it was pulling as didn't have a taco, probably doing top speed of about 150 km/hr before nerves & brake fade came into effect ...

Silverbullet wrote: Might have to program a rev limit into the Megajolt for safety reasons

I wonder does the Megajolt you have contain a OBD II outlet or some way of plugin in a monitoring system ?

That would be one way to see what RPM's you are getting ...

Cheers, Bantum ...

Silverbullet · Post by **Silverbullet** » Fri Mar 18, 2016 6:06 pm

Bantum wrote:Rarely
I wonder does the Megajolt you have contain a OBD II outlet or some way of plugin in a monitoring system ?

That would be one way to see what RPM's you are getting ...

Cheers, Bantum ...

Not OBD, but you can plug a laptop in via serial/VGA port for programming the ignition map and you do have this screen

Thread derail over - What bad things happen to an EA81 when you over-rev them? Broken con-rods? bent crank shafts? Blown up crank case?

Subydoug · Post by **Subydoug** » Fri Mar 18, 2016 8:41 pm

I set my redline at 5500 because Im already asking for it

. I don't think you will hurt anything revving it up. Its got a square bore from memory and I personally think the con rods are more then up for the amount of power going thru the engine. The heavy pushrod valve system and large single valves will be the choke point. Better on an ea82, but still large valves. Well done Though Jonno, 90 in second gear. I thought about giving it a go in the vortex the other day but watching how slowly the tacho creeps up in that car I couldn't be bothered waiting

.

Regards

Doug

Post by **TOONGA** » Fri Mar 18, 2016 9:19 pm

Silverbullet wrote: What bad things happen to an EA81 when you over-rev them? Broken con-rods? bent crank shafts? Blown up crank case?

That is the worst end of the scale, normally the valves bounce / float causing a loss of power. the valve bounce / float can lead to bent valves as well.

TOONGA

YouTube · Post by **El_Freddo** » Sat Mar 19, 2016 6:50 am

Either way the ea81 is still a piston engine at the end if the day so any one of those things could happen. Typically a conrod through the block comes after hearing a knocking sound on start up or if it's really bad - all the time.

With a fresh rebuild it should be able to take 4000-5000 rpm all day every day quite easily IMO. Your fuel economy won't like you for it though!

Cheers

Bennie

Phizinza · Post by **Phizinza** » Sat Mar 19, 2016 8:11 am

The aero guys would take off at 10000rpm and cruise at 8000 in their modified EA81s