Offshoreonly.com - Dry exhaust

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I am having the same problems with my emi thunders. i have two 500hp motors just redone with three hours and i noticed water in the oil on one. i pulled the motor figuring i had a bad gasket or other internal problem and everything checked out fine. put the exhaust back on and ran motor for about twenty minutes on dyno and pulled exhaust off and it poured out of the manifold. Im getting reversion. I already had them make the risors with a 6 iI contacted EMI and they want me to send the risors back so they can modify them. Can you please let me know what exactly they did when you sent yours back. Im considering just to go dry to make sure i dont have anymore issues. Thank You! Frank

Had Cmi and went with a less radical cams to prevent reversion. Didn't work. Switched over to full dry. Might have to put mufflers on but so far no water in cylinders...

Quote:

Originally Posted by CAPTAIN JACK (Post 3986347)

Crap, now you guy's are scaring me. I've been piecing my engine together for 2 year's now and finally getting close to starting it. I too went with EMI thunder also with the long risers, my cam is a little bigger. 234/244 @.050 .629/.612 114 LSA , Does anyone think this cam will be a problem? They are going to have to lock me up if I have anymore issues with this #%$#$%#%$ boat.

I am having the same problems with my emi thunders. i have two 500hp motors just redone with three hours and i noticed water in the oil on one. i pulled the motor figuring i had a bad gasket or other internal problem and everything checked out fine. put the exhaust back on and ran motor for about twenty minutes on dyno and pulled exhaust off and it poured out of the manifold. Im getting reversion. I already had them make the risors with a 6 iI contacted EMI and they want me to send the risors back so they can modify them. Can you please let me know what exactly they did when you sent yours back. Im considering just to go dry to make sure i dont have anymore issues. Thank You! Frank

I love it when people post negative comments about products thay have not even used....not you guys....call EMI..ask for chris,tell him you guys want to make your risers semi dry pipes which go through the transom..you will have to give him a measurement and most end up being 30 to 40'' long..yes thay are loud but sound way cool..

also make sure your engines are operating at a minimum of 140* or the manifolds will sweat and act like reversion but they are doing the same thing the gil's do but eddie dont make the ss plate that burns odd the moisture..

The angle&drop have a lot to do with reversion. I have under the swim platform tips with CMI e tops. The drop is almost straight down . The drop is about 14".My cam is [email protected] on 112 lobe ctr. Never a sign of reversion.

I agree, call Chris at EMI. He has always been great to work with. Check this thread out.

http://www.offshoreonly.com/forums/d...e-exhaust.html

Ok so I shipped the risers back and looks like Im def. going to have to go dry with running them through the transom. My outlets are about 7 inches higher then normal Bravo exit locations and emi feels I dont have enough pitch on the pipes. anybody have an idea how much space is ok heatwise my pipes will exit under swimdeck with about 4 inches between the pipe and deck. Not sure with the dry exhaust if this will be to hot? Thanks.

You had to pay for it because the reversion wasn't their fault. I don't care if it is on a 112LSA, that cam is risky at best for not having reversion. They can't control what other components are in your build such as intake, carb, head design, intake port velocity, compression ratio, your idle speed, your ignition timing. You tell me which one of those is their fault. I only bring this to your attention because I spent a lot of time on the phone with Bob (RMBuilder) talking about reversion and cam timing isn't the only factor. It is a big factor, but you can build two identical engines, with the exception of say the AFR 305cc heads on one motor and 345cc heads on the other. The 345cc headed motor will be more susceptible to reversion due to the slower port velocity.
Their HP claim is based on what the manifolds can flow.

Got drys need wets if interested - [email protected] thanks