New 8.2L Mercruiser engine
 

I am sure most of you know already but I finally talked to a Mercruiser guy in the know and the new 8.2 engine is a standard Gen VI 502 4.47x4.00 block. Same as the 525 and the old 502 Magnums. 8.75:1 compression, 87 octane. Nice, glad to see it back. Should scream once after market exhaust is available.

You brought up something interesting. I said WOW these babies would put out 50 more HP without that converter if you put a nice set of headers on it. The merc guy said it would basically blow up plus it immediately voids the warranty.

Post warranty it seems you could rid the catalyst and gain some hp.

Lots more flow so need a reflash I am sure. You would be trying to build a 525 clone. Cam, flash, Sport tubes, heads are close I hear, many other things I am sure to get toward a 525.

Sounds cool, I am sure many will try it.

Why upgrade the new 5.2 toward the proven 525?
 

It is simpler and also warranteed to start with a 525 from Merc Racing. Over 500 the cats are not required any way. Why do all that work?

Cost and availability. Lots of boat will come through with this new 8.2L and will be reasonably priced. People will love them as is for a few years and then start to tweak. Since you are starting from a platform similar to the 525, that's what people will shoot for. In 3-5 years there will be 100 threads on it.

I think that comment by the rep was probably a skewed statement. Depending on the restriction of the cat on this new engine removing it may make a lean condition. Therefore requiring more fuel either by way of pressure, larger injectors or an ecm flash. Possibly even a combination of them. I have yet to get one in to tweak yet for obvious reasons, but there are things that must be considered on some of the new units when adding or modifying things. So I dont believe the engine would fail simply because of free flowing exhaust, but failure to compensate other areas when adding a free flowing exhaust on some units can potentially do it if there is not enough margin built into the rest of the systems.. ;) This engine according to my rep will also have hypertectic pistons like the 496's, so being careful on mods will be important from what my rep has told me.

I too think that there will be a manufacturer that pops out an exhaust upgrade kit for the new 8.2, but it will probably be a while & it wouldn't surprise me to see it be more than what the 496 kits were fetching..

One other food for thought, depending on where you live & boat with these running an emissions motor without a cat may end up being cracked down on & allow for the law to issue tickets..

Jamie / Lakeside

Depending on the age of your boat along with a few other regulations, you can buy the new 8.2 Mercruisers without catalyst converters. See http://www.perfprotech.com/store/art...arch_main.aspx
for the regulations and talk to your favorite Mercruiser sales representative. It's a bit of messing around, as you have to swap them for an old engine and cash, but it can be done.
I bought two without cats and plan on upping the hp as soon as the gurus crack the code on the ECUs.
Bring it on!
I'm happy to be the guinea pig.

And I guess where you live ...............

They have forged pistons and are closer to the 525 already then they are to the old 502MPI. The one's running CATS have two computer's one controls the emission side of things, O2 sensors and stuff and they talk to each other so dumping the CATS may be a bit tricky. I'm sure Dustin Whipple or someone will come up with something before too long, depending on how the EPA or whoever is going to enforce emissions... Other then that there's nothing stopping anyone from using an aftermarket controller. The Holley HP/Dominator system is proving to be very durable in the marine environment and is easily adaptable.

OK, so who has one and is interested in playing with them? The first thing I'd be interested in would be the wideband a/f data of just how lean or rich it runs. The stock narrowband sensors are only going to be useful at or near stoichiometric values, and we all know Merc doesn't like to run them at those a/f ratios much.

I'd be willing to supply the widebands and LCD monitor device to log the data with, if someone has a boat and is willing to work with it. It will be interesting to see what the ECU does if you unplug the either the upstream or downstream O2 sensors. If either sensor being unplugged doesn't change the driveability of the engine, then the stock location could be used for a wideband sensor as well. I saw them at the LA Boat Show and the sensors are the standard 18mm size.