Engine Build Concerns

B

BigTexas68

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Mar 5, 2014
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First off I am new to this forum. I recently had a cracked piston in my LMM and went back with the 16.8cr Mahle Motorsport Delipped Pistons. The cylinders measured 4.056 and were honed using a bead hone. Oil clearances were well withing spec and std.bearings were installed and grade C headgaskets. It had a B on the right and C on the left. My compressor wheel had some damage and I installed a Batmo. I have 1,000+ miles on it now,no blow by and it has started to loosen up but it still feels down on power in the 2700-3200 rpm range. I have the rail pressure,boost and pulse width. It just feels like a dog. I'm down 8mph in 1\4 mile speed. I have stepped it up to my 390rwhp tune.

Does running these pistons require different tuning to make the the same power as the stock piston design or does it take longer to get the cylinders polished to get rid of the resistance?
It was a little noisy at first and I had to make some timing adjustments in the low rpm load areas. It seems to be taking the fuel better now.
 
Maybe consider letting someone else take a swing at tuning it? Not saying you aren't capable, but guys like Mark, Rob and Tony that do this every day, might notice something in the logs that you might not pick up on??
 
I know they are great tuners. But this isn't my first one to tune. The truck made great power before the build without any issues. Im confident that its not the tuning. I will put some more miles on it and get it loosened up before I start over with drastic tuning changes. It feels like its just tight. I will be putting a load behind it this weekend and see if that helps.. I had a SBC that took some time to finally get broke in.
I'm getting the air flow,boost,rail pressure and pulse that is being commanded.
 
BigTexas68 said:
I know they are great tuners. But this isn't my first one to tune. The truck made great power before the build without any issues. Im confident that its not the tuning. I will put some more miles on it and get it loosened up before I start over with drastic tuning changes. It feels like its just tight. I will be putting a load behind it this weekend and see if that helps.. I had a SBC that took some time to finally get broke in.
I'm getting the air flow,boost,rail pressure and pulse that is being commanded.
Click to expand...

I actually saw a thread like this the other day but the guy was getting a lot of blowby. He just beat the piss out of it and it fixed his problem haha. Hopefully you get it figured out!
 
I gave it 200 miles before I started putting some power to it. I drive 150 miles a day to and from work with mixed driving conditions so that should help . I think the honing was a little to coarse for plasma moly rings.
I don't have any blow by at all. The pistons and batmo are the only things that are different. The engine sounds better than the old one. It always had a little piston slap untile it warmed up. Done it since it had 50,000 miles on it.
I'm kind of on the fence about the batmo wheel. It makes boost and sounds good,seems to have a broader torque curve. I will know more after it gets broke in.
 
I know when guys first started tuning LMMs with different chargers they were having issues with underboost codes and then it would kill power but I wouldn;t think the batmowheel would have any effect on that. Hopefully someone else can chime in. I know this might sound dumb but any time I have any issue with my truck I go to the fuel filter first haha.
 
Yeah I would definitely look at the filter if I wasn't hitting the commanded pressure. The boost isn't laggy on the bottom end.
I've tune a couple LMM's with Garrett 4094vvt on them and haven't had any problems making them work.

I figured since I have good boost with the batmo that its not that. But as rpms and load go up I takes longer to get from 2700-3200rpm.
 
Update- Finally found my problem. It ended up being clogged injector nozzles. I had sent them to a shop for clean/test and I believe they just pushed all of the crud in the fuel inlet down to the tip. I put new nozzles on and its runs better than ever.
 
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