Max rpm for using thru-prop exhaust?
#1
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Thread Starter
Max rpm for using thru-prop exhaust?
I don't want to get any reversion problems but wondering if there is a max rpm for using the corsa thru-prop vs. transom? This 509 sounds pretty damn rowdy at idle with 10.2-1 C/R and a Marine Kinetics .600" lift cam....... I have about a 15 minute run past at least 100 waterfront homes at idle power to get to the open bay....... This thing sounds downright angry with no mufflers!
My marine guy did a great job moving the transom exhaust holes up about 5" as the 496 exhaust with the tall risers was way higher than the stock 502 setup.... Plus I like the idea of the flappers sitting above the waterline...... TBF
My marine guy did a great job moving the transom exhaust holes up about 5" as the 496 exhaust with the tall risers was way higher than the stock 502 setup.... Plus I like the idea of the flappers sitting above the waterline...... TBF
#2
Registered
The hole through the gimbal is actually quite small like 1.5"-2" diameter and from there it is a long uphill stretch to the headers, I don't think you would have any reversion problems, but I wouldn't use the through prop at much above your minimum planing speed.
#4
Ginger or Mary Ann?
Charter Member
Do you have the accordion exhaust bellows connected to the drive? If so might investigate replacing that with the tube type so the exhaust isn't forced to go thru the prop reducing back pressure
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Some people are like Slinkies - Not really good for anything, but they
bring a smile to your face when pushed down the stairs.
Some people are like Slinkies - Not really good for anything, but they
bring a smile to your face when pushed down the stairs.
#5
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I also heard 2500 r.p.m. Very considerate for you to be thinking about the noise level.
Always a good idea to look out for the performance boat image before it becomes a problem.
Always a good idea to look out for the performance boat image before it becomes a problem.
#6
Registered
Thread Starter
Well, it was not too bad.... Idle speed is not too loud but when I put a load on it holy crap! I came in at sunset and anytime I come in late I will keep it thru the prop.... I do have the accordion style tube so maybe I will change it over....... Thanks.....
#9
Ginger or Mary Ann?
Charter Member
For reference...There are cruisers I run with that are straight thru prop exhaust with BBC's. I can't see those being much different than a HP motor being ran with closed exhaust at a lower RPM for the range you are referring too. Not like you are wanting to run WOT with exhaust closed, while these cruisers do it w/o issue.
__________________
Some people are like Slinkies - Not really good for anything, but they
bring a smile to your face when pushed down the stairs.
Some people are like Slinkies - Not really good for anything, but they
bring a smile to your face when pushed down the stairs.
#10
Registered
i was thinking along US1's line of reasoning. 260 thru 330 hp uses thru prop as only option. if your secondaries aren't opening, you are probably not into too much back pressure.