2000, 502 mag minor upgrades
#31
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The 34' Phantom with 32" Bravos was turning 4900/4950 rpms before changing from cast-iron exhaust to Gils. ECU were reprogrammed to increase the rev-limiters, and what ever else Tyley Crockett knew that would help (boat still idles at 650 rpms), the larger flame arrestor is more aestically appealing and may gain only some minimal power.
Ther bottomline line is that the same 32" Bravos are now spinning 5100/5150 rpm. The boat was a consistent 84/85 mph boat, now it will run 87/88 mph consistently.
That is the gain in speed gain my father experienced from these changes, as far as how much more hp was gained is ????? Don't know hp gain.
I don't know exactly how much the Phantom weighs, ask Will Smith at Phantom Boats.
Hope that clears up any confusion.
If you want to get some better info modifications, ask Smitty, "Artic Friends," he is very knowledgeable with 502 MPI's and engine mods, he knows his chit!
Ther bottomline line is that the same 32" Bravos are now spinning 5100/5150 rpm. The boat was a consistent 84/85 mph boat, now it will run 87/88 mph consistently.
That is the gain in speed gain my father experienced from these changes, as far as how much more hp was gained is ????? Don't know hp gain.
I don't know exactly how much the Phantom weighs, ask Will Smith at Phantom Boats.
Hope that clears up any confusion.
If you want to get some better info modifications, ask Smitty, "Artic Friends," he is very knowledgeable with 502 MPI's and engine mods, he knows his chit!
Last edited by Smarty; 09-23-2007 at 08:53 PM.
#32
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They have programs that will give the engine a little more kick if you are willing to run 91 octane. I'm assuming the timing is changed along with upping the rev limiter.
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Patrick
Patrick
#33
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Rev limiter was increased to 5400 rpm. Boat runs on 89 octane.
#34
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For the guy who's just learning about this stuff. These stock cast iron heavy exhaust manifolds that you normaly see on these lower grade engines are obviously adequate enough to fulfill the manufacturer's power output goals i.e. just enough to get the job done.
I have had to learn since the early 1980's that having or adding a better breathing exhaust system is the first REAL step in gaining any kind of power or potential for power----even if you only gain very little on top.
I used to hear the 1960-70's term "Free Horsepower" by adding a better breathing exhaust system. The idea being that by adding a better breathing exhaust you will make more horsepower or at least creat a platform for creating more horsepower as you upgrade/modify the engine. Of course we all know that a marine aftermarket exhaust system isn't exactly free. Generaly speaking, once a better breathing exhaust system is installed, then the better the engine will respond to any mods/upgrades thereafter.
Sorry for being so long winded. Have fun
#35
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Changing out the stock cast iron exhaust is always a great place to start. I run Stainless Marine on my 502MagMPI.
A good HP exhaust manifold system will give you better mid range power and 100-200rpm extra on top. Headers like CMI E-tops will not gain you much more than a set of Stainless Marines.
You do not need to recal the ECM with just an exhaust change. Maybe up the fuel press a little if you go with headers.
Long tube headers with a cam change could give you another 100HP.
A good HP exhaust manifold system will give you better mid range power and 100-200rpm extra on top. Headers like CMI E-tops will not gain you much more than a set of Stainless Marines.
You do not need to recal the ECM with just an exhaust change. Maybe up the fuel press a little if you go with headers.
Long tube headers with a cam change could give you another 100HP.