Are Headers worth it?
05-30-2002 | 07:28 PM
#1
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From: Houston, TX, USA
Are Headers worth it?
A none computer boater asked me to post this question. I gave him my answer but he did not like it.
Boat is 2000 28' daytona, twin 454 (365hp) mpi engines with stage 1 prochargers. Motors have the stock mercuiser exhaust. He is wanting to install CMI elbow top headers. Do you think it is worth the money to change to headers or would he be better off to put the money towards shorty drives? It is well documented that the shortie drives in this boat will give him 5-10 mphs. Anyooe have guess on if this will give motor more HP since he has EFI. Would the EFI need to be reprogramed? Has anyone done this before & what were the results?
Boat is 2000 28' daytona, twin 454 (365hp) mpi engines with stage 1 prochargers. Motors have the stock mercuiser exhaust. He is wanting to install CMI elbow top headers. Do you think it is worth the money to change to headers or would he be better off to put the money towards shorty drives? It is well documented that the shortie drives in this boat will give him 5-10 mphs. Anyooe have guess on if this will give motor more HP since he has EFI. Would the EFI need to be reprogramed? Has anyone done this before & what were the results?
05-30-2002 | 08:34 PM
#2
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From: Tulsa, OK, Grand, Beaver, LOTO
Shorties!
If he is looking for speed the shorties are the answer, if he want's eye candy, CMI's.
Dustin told me that my 454mag efi with his S/C would only gain 20 ponies (dyno tested not wild guesses) compared to the stock Merc pieces. Gain is less than an N/A application because with the blower pushing you are less reliant on efficient scavenging.
20 ponies per side will not touch the gains to be had with the shorties. HB had an article where they put 2" shorties on two different 28 daytonas, one custom N/A and the other custom blown- If i rememper right they gained close to 11 and 15 respectively + improved the cruise.
If he has stock programming with the Prochargers that is the first place i would spend money. Good luck- I hope this info helps!
Dustin told me that my 454mag efi with his S/C would only gain 20 ponies (dyno tested not wild guesses) compared to the stock Merc pieces. Gain is less than an N/A application because with the blower pushing you are less reliant on efficient scavenging.
20 ponies per side will not touch the gains to be had with the shorties. HB had an article where they put 2" shorties on two different 28 daytonas, one custom N/A and the other custom blown- If i rememper right they gained close to 11 and 15 respectively + improved the cruise.
If he has stock programming with the Prochargers that is the first place i would spend money. Good luck- I hope this info helps!
05-30-2002 | 08:38 PM
#3
I hate the winter!!
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From: long island, new york
Personaly I don't have any experience with headers, but I did change my stock exhaust for a set of Gil Wet Offshores. I picked up about 200 rpm and about 2 mph. My motor is otherwise all stock. I didn't expect to pick up any more than that. However, in your friends case, having a supercharger changes things. That Procharger is forcing all that extra air into those cylinders while the exhaust has a cork in it. I think he would pick up from that change over.
05-30-2002 | 08:41 PM
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From: LaPorte IN.
Blower motors need all the help they can get on the exhaust side. On stock 454 mags 20HP, but on the charged motors I would say 50 HP easy per motor. The shorties are a good idea also. He should do both. Then he'll be flyin!!!
