496 HO - Remove Turbulator and Lost Speed?
08-19-2009, 03:51 PM
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Don't have 496's , but experimented on my 6.2's [ 377cu]
removing the turbulators on the port engine first. Didn't make any difference , rpm's [ speed] stayed the same. Same result for the starboard engine. The exh ports at the riser joints are small for both 496 and 377 , so the turbulator really doesn't make a diff in or out. Putting mufflers on or slip ins at the tips would affect rpm's at WOT , dropping as much as up to 200, hence loosing speed. The turbulators get red hot at high rpm's and burn up water droplets [ condensation ] while going down to idle while the engine cooling down. It's a Merc warranty issue .
An aftermarket exhaust manifold/riser and slightly more cam would be your best bet for some performance gains.
removing the turbulators on the port engine first. Didn't make any difference , rpm's [ speed] stayed the same. Same result for the starboard engine. The exh ports at the riser joints are small for both 496 and 377 , so the turbulator really doesn't make a diff in or out. Putting mufflers on or slip ins at the tips would affect rpm's at WOT , dropping as much as up to 200, hence loosing speed. The turbulators get red hot at high rpm's and burn up water droplets [ condensation ] while going down to idle while the engine cooling down. It's a Merc warranty issue .
An aftermarket exhaust manifold/riser and slightly more cam would be your best bet for some performance gains.
Last edited by spectras only; 08-19-2009 at 03:54 PM.
08-19-2009, 04:17 PM
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Spectras, Thanks for the advice. Unfortunately, Considering that I would have to take the motors out anyway to install the headers, it would be a tough call to spend 10k on a set of headers when for roughly the same price I could drop in a set of 525s with around the same amount of hours. With a 525 I would pick up over twice the power gains and also leave room for improvement ala a Whipple kit which would last much longer on the better stock bottom end than on a 496. If i can get a better deal, I may think a little hard about it but given that the 496 needs ALOT of parts to really get where i want to be It will be cheaper in the long run to get another set of motors.
Last edited by CheckedOut; 08-19-2009 at 04:23 PM.
08-19-2009, 04:20 PM
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$10K that is a stretch for Blue power... In this market you couldnt get more that $3000 a piece for used 496 HO's...
You can buy new 496 Mag HO's from IMCO for $5000!
Checked out - If you take the manifolds off and have them ported, you might pick up 100 RPM. A few people on OSO have been successful porting them. Even when I installed Stainless Marine Manifolds and reprogrammed the ECU I only picked up 150-200RPM.
You can buy new 496 Mag HO's from IMCO for $5000!
Checked out - If you take the manifolds off and have them ported, you might pick up 100 RPM. A few people on OSO have been successful porting them. Even when I installed Stainless Marine Manifolds and reprogrammed the ECU I only picked up 150-200RPM.
Last edited by Keith Atlanta; 08-19-2009 at 04:25 PM.
08-19-2009, 04:31 PM
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Wow that is rough........Considering that dealer cost is 14k. I would believe that when I see it. They probably dont have a warantee and were out of a repo or sunk boat.
Last edited by CheckedOut; 08-19-2009 at 04:43 PM.
08-19-2009, 05:24 PM
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Truck motor with some marine parts.
I just shopped all over for 496 HO's with warranty and paid more than I would have liked.
525's are higher in price then metioned as well from what I found.
08-19-2009, 05:33 PM
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Spectras, Thanks for the advice. Unfortunately, Considering that I would have to take the motors out anyway to install the headers, it would be a tough call to spend 10k on a set of headers when for roughly the same price I could drop in a set of 525s with around the same amount of hours. With a 525 I would pick up over twice the power gains and also leave room for improvement ala a Whipple kit which would last much longer on the better stock bottom end than on a 496. If i can get a better deal, I may think a little hard about it but given that the 496 needs ALOT of parts to really get where i want to be It will be cheaper in the long run to get another set of motors.
