SB

iTrader: (1)

One other thing, that just popped into my head while talking to a customer, lol, is double stacking the FA. I remember, way back in the day when I was actually young, seeing some hotrodders double stack their factory flame arrestors. Too young to bother to ask, but it looked like they removed the lid off one, base off another, and sandwiched them together some how.

SB

iTrader: (1)

Listing + pics off all Mercruiser flame arrestors, including clamp ons:
http://www.marineengine.com/parts/me...alog-00809.htm

Revspan

Well, I found and ordered two new Mallory FAs. They will require a little modification, but will certainly help in airflow. Over the weekend, I will be also getting some testing done regarding more airflow and the impact on engine temps.

Revspan

I am now convinced more than ever that there is a breathing issue in the 292. Pulled the beauty cover off the starboard engine and during a hole shot, this engine world pull 2-300 more rpm than other engine. The first time this had ever happened. Repeated and this is a fact. Once on plane, the rpm would balance, but the starboard engine made more torque with the covers off. In addition, with the hatch cracked about 8", intake temps would steadily drop. With it closed, it would steadily rise. Outside temps at 86 and engine intake temps would run up to 135. Open hatch as little and the temps go to 115.

Not sure my next step, but also did a quick run with hatch cracked and hit 66 with full tank and two adults. Made 5000 rpm with stock 28p B1s

08 fastech 292

We will be out tomorrow and I will pull the beauty covers and see what happens.

What model FA's did you order?

Revspan

I ordered 9-31103. I don't have them yet, but they will certainly flow more than the stock ones, eliminating the possibility of any restriction. I will be interested if your boat behaves the same without the beauty covers. To repeat the test, take off one cover, let the engine get really soaked, have the hatched cracked....I used a 2x4 on edge. So, the improvement is due to the engine getting access to cooler air quicker. It makes sense to me....especially when you have the huge cats and heat exchanger for closed loop cooling surrounding the TB.
Good luck.

4mulafastech

Revspan - Very interesting topic and thanks for sharing your findings so far. I was in our 292 yesterday and took a few pictures of the stock flame arrestor to add to your thread. Does yours look the same?

My engines are 2006 6.2 liter MPI's with no cats. I plan to try and get temperature measurements with hatch closed plus open some and will add to the thread for comparison. Curious, where are you putting the 2X4's for running with the hatch cracked?

I was looking at how the engine compartment is ventilated and mine is the same as you described. Like you said there definitely is room for improvement. I like your idea about ducting cooler air to directly feed close to the flame arrestor.

Good stuff and looking forward to reading how your new flame arrestors work out!

[ATTACH=CONFIG]557780[/ATTACH][ATTACH=CONFIG]557781[/ATTACH][ATTACH=CONFIG]557782[/ATTACH]

4mulafastech

SB - Our flame arrestors are molded plastic and not able to be taken apart and double stacked. Great idea though if we could.

Thanks for all the flame arrestor links and information! There has got to be one in all of these that could be modified and make a major improvement compared to stock.

Revspan

Dave, those are the same as mine....just imagine a log exchanger in front, cats on either side and hoses to all of it. But, the solution for the arrestor will be the same, as the layout and clearances should be common.
I got a mock up today of piping that will work in the starboard side. Gonna stare at it, test it and maybe convert to 4" aluminum intercooler piping with silicone couplings. Just need to see what the FA ends up looking like, and then make it look professional. The piping layout I made has a nice dip in it too, to make sure there is kind of a p-trap in case water got in it. Drill a small hole in the bottom and it should be good.
I can't. Post pictures, but if you shoot me a pm with your email, I will show you what I am working on.

Oh... And the shelves for the Bimini top had to be removed. Nice for storage, but is a huge obstacle to get around. For now, they are on the garage shelf.

4mulafastech

PM sent Kai.