Subaroo engine prop question

[mcbirdman]

I talked to a man who has been working soobs up to 160 hp. Specifically : 160hp@5400\173lbs torque@3400 RAM Ea81 MPEFI Dualport.

He wanted to lose the 39 lb 2.2:1 redrive if possible and wondered what prop could be used to get like 150 hp at 2900rpm and also handle 120hp @3700rpm, I believe. If I left something out in this question please let me know. I get confused about the hp and the lbs of torque.

The idea is that he thinks he can get the weight from 197lbs to 158. IF he can get rid of the redrive. Any help anyone could provide could make a big difference in packages available. We are interested in the posibility of putting these highly rated engines on our LW's.

Thanks for any information or input that I can forward to him. jtm

[Thumpernator]

James,

I may be full of it,,,,well,,,actually I am.......but I find it very hard to believe that you're going to be able to get 150hp at 2900 rpm from an EA-81.

But if you need to absorb a lot of power, I'd talk to Lonnie Prince. Remember, ya gotta keep the tip speed sub-sonic.

[mcbirdman]

HI Dave - You are right somehow... unless I simply transposed the rpms. As written 150 @ 2900 wouldn't make sense if 120hp at 3700. I'll have to check in with him again....

Dave go to .... http://www.ramengines.com/index.html and look at the engines. they are putting out more hp than comparable other engine modifications.... He said stock cfm is like 117cfm and sub 4 typical is 176 and he is getting 189. Also said he uses a deck to mount the heads taking into account exactly how bolts around the head will deform on every engine as it is torqued down. Using the deck he gets the perfect shape that gives him the 100% ring seal when typical is only 87%sealing. Fuel injected multiport heads and direct fire. with 4 coils. Also uses roller rockers that increases hp by 10-12hp. I think having a dyno to chart things out really helps him see if things are better or not. It appears that it is performing very well. Fuel injection works off from vaccum which helps with altitude changes better than sensor setups. Cockpit adjustability also ! Exaust and intakes are tuned and tested....

Forged heads that are a total of 322 grams lighter than standard and can stand up to 4400degrees instead of standard 2800.

Also note that Bauer Aviation has chosen them for OEM engines.
Let me know what you think, Good to hear from you, Thanks, jtm