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RAM Performance (140hp N/A EA81)


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I was not necessarily looking at the long blocks but the custom dual-carb manifolds and forged piston kits. The bore and stroke are the same, but the cam profiles in those motors is what sets it apart from a torquey low-end setup... who says you need to run the same cam? Anyways, the peak torque curve usually comes at about 2k rpm for these motors, and torque is what is needed for crawling. Just imagine if you added a turbo or supercharger to that motor and had it tuned...

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Gearing is whats needed for crawling. Our 80hp EA81's will crawl no problem, but the 4spd D/R has to be replaced. Which most have done recently. An engine like this would be better suited in a nice EA81 Coupe, or Hatch to race on some tarmac somewhere :) And yeah, a turbo would be super sweet on a setup like that.

 

-Brian

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  • 11 years later...

Didn't someone on here actually get one of these motors at one time? I thought I remembered a thread from around 2005 where someone got one. I wonder how well it held up. I have thought about getting their pistons and heads when its time for me to do a rebuild.

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yeah, those are the best EA81's you can get. But they're built to make peak hp at high rev's, and hold those rev's at high altitude for a long time. Probably not the best for street use unless you like cruising at 6000rpm and dont like shifting.

 

 

-Brian

No airplane engine ever has cruised at 6k rpm. It is so rare to ever get a propeller driven engine above 2800 rpm. The never exceed rpm on most single engine Cessnas is 2900 rpm. The little experimentals that people are putting ea's in certainly don't turn 6k.

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good bit of info to chew on there Lucas. Sort of makes sense to have the engine cruise at its torquiest rev for fuel efficiency, longevity, reliability etc

In the airplane world is most about fuel efficiency. On the smaller cheaper single engine airplanes ( any Cessna 100 series, piper single engine) they don't have any gear reduction for the prop so the tip speed of the prop is a huge issue. The 172 I fly regularly has a prop governor that controls the prop pitch. Prop pitch is used to control rpm more than the throttle.

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Those SUB4 guys in NZ created some DOHC EA82 heads at one point... Crazy good fabrication.

 

It would be interesting to see how much power one could get out of a built EA82T with these heads and a spider manifold...

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Ron @ Ram performance was great to work with. He is quick to respond by email.

 

He builds more than just aviation motors.  He builds all performance motors.  I think the FB page is "Ram performance engines"

 

I had him do my heads.  Hopefully i will have the car up and running this week.

 

He told me the biggest bang for the buck is to get bigger valves.  

I asked him to raise compression.  

I did my own port and polish.  I couldn't afford his flow balancing at this time.  

I also had him weld the cracks in the head near the valves.

 

He sand blasts the head so any polish work will have to be redone after he has it.

 

Turnaround time was about 3 weeks.

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Ron @ Ram performance was great to work with. He is quick to respond by email.

 

He builds more than just aviation motors.  He builds all performance motors.  I think the FB page is "Ram performance engines"

 

I had him do my heads.  Hopefully i will have the car up and running this week.

 

He told me the biggest bang for the buck is to get bigger valves.  

I asked him to raise compression.  

I did my own port and polish.  I couldn't afford his flow balancing at this time.  

I also had him weld the cracks in the head near the valves.

 

He sand blasts the head so any polish work will have to be redone after he has it.

 

Turnaround time was about 3 weeks.

 

Good to know!  Now I just have to decide if I stick with the crummy old EA81T or start saving my dimes for an EJ swap...

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hmmm, and many years ago when I got my first Sube, asked of my trusted, aging , race caring machine shop guy - felt EA81 valves were big by some standards and they would be good enough ???

 

Wonder what the compromise is when going bigger valves ?

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Another good question Jono,

 

We have all done the "bolt the bigger carb on" thing, as I did with my 38/38 and defied advice from those that have done it....to see if it can be done. But really, modifying a stock engine id more a science isn't it?

 

That's just my view. I mean in basic terms allowing an engine to breathe better eg larger exhaust and larger manifold. But even these mods can have traps. Make an exhaust too large with little back pressure and it causes issues. How much back pressure is ideal? How do you measure that pressure? From where the exhaust exits the head or 3 metres away?

 

Manifolds- does bigger mean better? Often it does but does it on a ea81/2 when is really more of a unique design? At 6mm bigger diameter my SPFI is likely double the volume of the stock ea81...does that have negatives? or real proven positives? Who knows? No one has posted not to use that manifold....so again, pioneering stuff and I love it as long as it works lol. To date for example a 65 on the idle primary jet was installed and a 70 is likely ideal. The 65 allows for the mixture screw to be 1.75 turns out....what is the goal. But I haven't seen a weber 32/36 use a 65 jet yet nor 70....mainly 50-60 max. So is that due to the manifold size? The short trike exhaust? The 9.5:1 compression ratio? Will the larger manifold contribute to better ecomony or worse?

 

So with the above, will bigger valves be wonderful or other things should be taken into consideration? Its a science

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