WOT with hatch open
#1
Registered
Thread Starter
WOT with hatch open
Yesterday I had an opportunity to make a WOT run with the engine hatch cracked open 2” in accordance to OTIS311’s suggestion.
Results: I made two passes. One with the hatch closed. One with the hatch open and flame arresters removed. I tried hard to duplicate the conditions one each pass (flat water, same starting point, same direction, etc). The pass with the hatch closed saw 76.1 on gps. The pass with the hatch open and arresters pulled saw 76.9 on gps.
Conclusion: Who knows. Did the open hatch make a difference? Did the absence of flame arresters make a difference? Was it just a case of two passes yielding two different speeds? If I knew it was the flame arresters, I would buy two K&N’s tomorrow. If I knew it was the hatch, then that’s too bad since I just get a bad feeling riding with it open. Also – with the hatch open the handling at top speed seemed to be a lot more squirrelly. May have been my imagination but I can’t help but wonder if it had something to do with all that air rushing into the engine compartment with no place to escape causing the ass end of the boat to do strange things.
Note: Both speeds posted above are below my best of 77.2 but I attribute that to the fact that it was 97 degrees out yesterday vs. the low 80’s during the 77.2 run.
Results: I made two passes. One with the hatch closed. One with the hatch open and flame arresters removed. I tried hard to duplicate the conditions one each pass (flat water, same starting point, same direction, etc). The pass with the hatch closed saw 76.1 on gps. The pass with the hatch open and arresters pulled saw 76.9 on gps.
Conclusion: Who knows. Did the open hatch make a difference? Did the absence of flame arresters make a difference? Was it just a case of two passes yielding two different speeds? If I knew it was the flame arresters, I would buy two K&N’s tomorrow. If I knew it was the hatch, then that’s too bad since I just get a bad feeling riding with it open. Also – with the hatch open the handling at top speed seemed to be a lot more squirrelly. May have been my imagination but I can’t help but wonder if it had something to do with all that air rushing into the engine compartment with no place to escape causing the ass end of the boat to do strange things.
Note: Both speeds posted above are below my best of 77.2 but I attribute that to the fact that it was 97 degrees out yesterday vs. the low 80’s during the 77.2 run.
#3
Registered
Thread Starter
By the way, if any of you guys with twin engines decide to pull the flame arrestors off and run with the hatch open at WOT, the noise sounds so sweet. It just screams
#7
Guest
Posts: n/a
I disagree, running with the hatch open with both the old and new motors gives and instant 100 rpm and about 1 mph. I've seen it enough times, so I know it works on my boat. In theory plus with two different motors, you guys have to have seen some gains. Later. A4
#9
Registered
Join Date: Jun 2002
Location: Central Ohio
Posts: 910
Likes: 0
Received 0 Likes
on
0 Posts
Before this thread, I've opened mine out of curiosity to see if there would be a performance difference. I opened mine about 2" and found that I instantly gained 100 RPM and 1 MPH.
I have an 272 w/502 MPI.
I have an 272 w/502 MPI.