01 Hp500 Efi Performance Upgrade HELP!!??
11-15-2011, 05:19 PM
#41
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So, basically you lose 15-20hp doing from a marine dry to a marine wet. So, does that transfer into the real world? Meaning would you see a 15-20hp increase going from full wet exhaust to dry or close to dry?
Most people go dry or close to dry because of reversion from big cams. But is there power to be picked up as well on engines that do not require dry exhaust because of reversion?
In realty I know it's not worth it to most to go to dry exhaust for 15-20hp. The cost and noise wouldn't be worth it to me. I am just curious if someone did want to if they would see a 10-15hp increase.
Most people go dry or close to dry because of reversion from big cams. But is there power to be picked up as well on engines that do not require dry exhaust because of reversion?
In realty I know it's not worth it to most to go to dry exhaust for 15-20hp. The cost and noise wouldn't be worth it to me. I am just curious if someone did want to if they would see a 10-15hp increase.
11-15-2011, 06:56 PM
#43
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So, basically you lose 15-20hp doing from a marine dry to a marine wet. So, does that transfer into the real world? Meaning would you see a 15-20hp increase going from full wet exhaust to dry or close to dry?
Most people go dry or close to dry because of reversion from big cams. But is there power to be picked up as well on engines that do not require dry exhaust because of reversion?
In realty I know it's not worth it to most to go to dry exhaust for 15-20hp. The cost and noise wouldn't be worth it to me. I am just curious if someone did want to if they would see a 10-15hp increase.
Most people go dry or close to dry because of reversion from big cams. But is there power to be picked up as well on engines that do not require dry exhaust because of reversion?
In realty I know it's not worth it to most to go to dry exhaust for 15-20hp. The cost and noise wouldn't be worth it to me. I am just curious if someone did want to if they would see a 10-15hp increase.
11-15-2011, 07:02 PM
#46
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On my dyno we always run wet exhaust and run all accessories ,same exhaust, tailpipes wet and alittle longer on my dyno the merc 500efi usually makes 500-515 hp a lot of factors to keep it all the same,weather size of engine 502-509-516etc,when we did the upgrades they made 610-620hp on the same dyno with the smae set-up,basically 100hp gain when i make small changes i always do them the same day to see if the gains are real(jets,spacers ,different exhaust0 as baseline hp can be a little different day to day,correction factors help keeping the hp the same but are not always perfect
11-15-2011, 07:07 PM
#47
If you just changed from wet to dry and nothing else you'll pick up a little horsepower but, if you're no longer limited in your camshaft profile by the wet exhaust you can see some very substantial gains. I was actually a little surprised that there was only around 30hp difference running a tuned dyno header with a decent collector, vs a good wet exhaust the first time I tried it. The reason is, the wet exhaust cam isn't designed to take advantage of the scavenging properties in the header. Same deal with wet marine exhaust vs dry. Get Bob to design a cam for the dry exhaust and you'll pick up a whole lot more then 10hp. Mixing water in your exhaust is just plain wrong and creates a whole lot of compromises that, unfortunately, we all have to live with it.
I ask these questions as it seems that a 502 is limited to the 550-575 real world hp range with wet exhaust, pump gas, moderate rpm, etc.
Last edited by onesickpantera; 11-15-2011 at 08:25 PM.
