docmanrich37

Let Lori drive because it looks to me that they're going faster,I mean the boat is going faster.

mwdill

might get a little more bounce

Baddogg

The Restrictor Plates Are There For A Reason Reversion If They Wernt Needed They Probably Wouldnt Be There. For 1-2 Mph I Will Leave Mine Alone. Who Needs A Motor Full Of Water!

mwdill

they were only in the early model 496's the later models don't have them,i believe it was an extra security measure on a new motor.

SHOWGIRL

The restrictor plate that you mention is called a Turbulator and is made for Merc by Gil Exhaust Systems. It is supposed to keep condensation out of the exhaust valves when the motor cools. My 2002 Baja with 496 HO's has them in place. I have also considered removing them. If anyone can verify their absence in newer 496's please let us know.

Dave_N

Last summer I installed a 2004 model year 496HO. It had the turbulators.

Dave

Harper220

Good points to consider, but sounds like they're not really necessary and safe to remove. I'll take all the free hp I can get, plus a little extra hp goes a long way in a cat...

Raylar

I will see if I can intelligently answer the questions and put a final light on the Mercury "Turbulator" plate in the 496 engines. First, all the 496's I have seen or checked seem to have the plate irregardless of year of manufacturer. Thats not to say Mercury has or will not change on certain production years and models. As I understand from Mercury engineers themselves, these plates wetre designed to catch small amounts of exhaust moisture, not reversion!, no plate will stop reversion, reversion is a function of cam timing and overlap and it does not exist per say in the 496 Mag or HO engines. Exhaust moisture, depending on the individual boat , exhaust design and exhaust system exit heights coupled with silent choice or otherwise can sometimes be a greater water generator issue in some hulls more than others. The plate was designed to provide a substantial shelf to catch small amounts of actual water and provide a place where exhaust heat could cook it off and keep it from entering the exhaust manifold and possibly getting to the exhaust valve, especially after the motor is shut off. The idea is not a bad one but the execution was not the best. first the inside diameter of this hole in the "turbulator is just over 2-1/4" inches in size. This does not seem like a serious dimension, however you need to understand that the inside diameter of the Mercury sweep riser is over 3" and about 3-1/2" at the location of the "turbulator" plate. This small opening becomes a substantial restriction to the exhaust gas flow at higher rpms, especially under full WOT periods. Remember this is a fairly high horsepower 500 cubic inch engine! We have done actual flow bench runs on the manifold and riser, with and without the turbulator plate and I can personaly tell you that removing the plate has a considerable affect on how much exhaust gas the manifold & riser plate can flow at what would be higher rpms and throttle positions. I wish the manifold designer-Gil? had just designed a little more down angle to the exhaust port entrance at the cylinder head flange and any need for the turbulator plate would have been completetly eliminated. The low pocket this would have created would cook off small amounts of water., but what the heck, I didn't design the manifold, and it's really not a half bad part. This manifold is every bit a good as a normal aftermarket cast manifold such as Stainless Marine, Gil, Eddie or Imco standard . If you have a boat that has a s-pipe drop tube between the riser na d the transom exit tip or your boat has a moderate drop between the riser exit height and the transom exit you should be able to eliminate the plate and get the horsepower benefits accordingly. If your transom exit height is close to the bottom of the Merc riser height, you have a silent choice system which you keep set closed for through the prop exit a lot or you are one of these boaters with a below the water line tip exit, swim platform cap over the tip and you back down hard a lot of the time, then you may be better off keeping the turbulator plates installed. If you can safefly remove them, especially with our BIGPOWER kit you will gain power at higher rpms. Remember any impediment to air flow into or out of a high performance large cubic inch engine, especially in marine use will have a negative affect on performance. Otherwise no one would need to purchase marine header or high performance marine manifold systems. I hope this clears the air and clarifies the issue. "Will the real Turbulator plate please stand up!"

Good Luck,
Ray @ Raylar

Harper220

That clears the air for me... thanks raylar

causin trouble

Heres what i did with mine