What all is different between the 502MPI's "97" and "98" ???????????
06-18-2015, 08:24 PM
#11
Registered
Both the Mefi 1 and Mefi 3 can be reprogrammed. The 2 main differences are that the 1 can not be used on a boosted engine (Whipple, Procharger, Vortech, turbo, etc.) It has no ability to tune in boost while the Mefi 3 can. Also, the Mefi 3 has MUCH greater resolution and tunability than the Mefi1. The fuel and spark tables especially are much larger, giving you more cells to work with. The Mefi 1 fuel table is laid out in 20 Kpa increments while the 3 is in 10 Kpa increments. Also, the 1 is every 400 rpm while the 3 is every 200 rpm, over 1200 rpm.
If you are staying NA, the 1 would get the job done, but the 3 would be a HUGE step up and would make for a much better piece. If you are going SC, you don't have a choice. To further confuse the situation, the Mefi 4 is even that much better. You have a 1 right now. If you are going to try to switch to a 3, you may have a tough time finding them. They are getting harder and harder to get. You would be better off getting a 4B and harness. The 3's haven't been made for a very long time. Mercury actually has a bounty on them right now. They will buy them from you. The 4's are easier to get and in some cases, cheaper. We just make our own harnesses. I would be hesitant to trust a 20+ yr old harness anyway.
There are no internal differences in the engines.
Eddie
If you are staying NA, the 1 would get the job done, but the 3 would be a HUGE step up and would make for a much better piece. If you are going SC, you don't have a choice. To further confuse the situation, the Mefi 4 is even that much better. You have a 1 right now. If you are going to try to switch to a 3, you may have a tough time finding them. They are getting harder and harder to get. You would be better off getting a 4B and harness. The 3's haven't been made for a very long time. Mercury actually has a bounty on them right now. They will buy them from you. The 4's are easier to get and in some cases, cheaper. We just make our own harnesses. I would be hesitant to trust a 20+ yr old harness anyway.
There are no internal differences in the engines.
Eddie
06-18-2015, 11:32 PM
#13
Both the Mefi 1 and Mefi 3 can be reprogrammed. The 2 main differences are that the 1 can not be used on a boosted engine (Whipple, Procharger, Vortech, turbo, etc.) It has no ability to tune in boost while the Mefi 3 can. Also, the Mefi 3 has MUCH greater resolution and tunability than the Mefi1. The fuel and spark tables especially are much larger, giving you more cells to work with. The Mefi 1 fuel table is laid out in 20 Kpa increments while the 3 is in 10 Kpa increments. Also, the 1 is every 400 rpm while the 3 is every 200 rpm, over 1200 rpm.
If you are staying NA, the 1 would get the job done, but the 3 would be a HUGE step up and would make for a much better piece. If you are going SC, you don't have a choice. To further confuse the situation, the Mefi 4 is even that much better. You have a 1 right now. If you are going to try to switch to a 3, you may have a tough time finding them. They are getting harder and harder to get. You would be better off getting a 4B and harness. The 3's haven't been made for a very long time. Mercury actually has a bounty on them right now. They will buy them from you. The 4's are easier to get and in some cases, cheaper. We just make our own harnesses. I would be hesitant to trust a 20+ yr old harness anyway.
There are no internal differences in the engines.
Eddie
If you are staying NA, the 1 would get the job done, but the 3 would be a HUGE step up and would make for a much better piece. If you are going SC, you don't have a choice. To further confuse the situation, the Mefi 4 is even that much better. You have a 1 right now. If you are going to try to switch to a 3, you may have a tough time finding them. They are getting harder and harder to get. You would be better off getting a 4B and harness. The 3's haven't been made for a very long time. Mercury actually has a bounty on them right now. They will buy them from you. The 4's are easier to get and in some cases, cheaper. We just make our own harnesses. I would be hesitant to trust a 20+ yr old harness anyway.
There are no internal differences in the engines.
Eddie
Oh, and not to be a contrarian, but I have and use a 20 year old MEFI 1 harness.
Last edited by Trash; 06-18-2015 at 11:35 PM.
06-20-2015, 09:30 PM
#14
Registered
Thread Starter
Both the Mefi 1 and Mefi 3 can be reprogrammed. The 2 main differences are that the 1 can not be used on a boosted engine (Whipple, Procharger, Vortech, turbo, etc.) It has no ability to tune in boost while the Mefi 3 can. Also, the Mefi 3 has MUCH greater resolution and tunability than the Mefi1. The fuel and spark tables especially are much larger, giving you more cells to work with. The Mefi 1 fuel table is laid out in 20 Kpa increments while the 3 is in 10 Kpa increments. Also, the 1 is every 400 rpm while the 3 is every 200 rpm, over 1200 rpm.
If you are staying NA, the 1 would get the job done, but the 3 would be a HUGE step up and would make for a much better piece. If you are going SC, you don't have a choice. To further confuse the situation, the Mefi 4 is even that much better. You have a 1 right now. If you are going to try to switch to a 3, you may have a tough time finding them. They are getting harder and harder to get. You would be better off getting a 4B and harness. The 3's haven't been made for a very long time. Mercury actually has a bounty on them right now. They will buy them from you. The 4's are easier to get and in some cases, cheaper. We just make our own harnesses. I would be hesitant to trust a 20+ yr old harness anyway.
There are no internal differences in the engines.
Eddie
If you are staying NA, the 1 would get the job done, but the 3 would be a HUGE step up and would make for a much better piece. If you are going SC, you don't have a choice. To further confuse the situation, the Mefi 4 is even that much better. You have a 1 right now. If you are going to try to switch to a 3, you may have a tough time finding them. They are getting harder and harder to get. You would be better off getting a 4B and harness. The 3's haven't been made for a very long time. Mercury actually has a bounty on them right now. They will buy them from you. The 4's are easier to get and in some cases, cheaper. We just make our own harnesses. I would be hesitant to trust a 20+ yr old harness anyway.
There are no internal differences in the engines.
Eddie
Great info and thanks. This is really getting down to the nitty gritty of build up options.
So here is another scenario that might make up my mind based on limitations. If I stroked these 502's would this intake system even be able to feed these engines? If the Mefi-1 could program the next prob might be the intake and if that is the case would it be better to scrap all the OE computer and go aftermarket with the intake and controllers?
Since the Mefi-1 rules out boosting, then, if I whipple charge does whipple have a control system or would I be better with the 4-system?
Would aftermarket or the Mefi-4 be better for build up options?
06-21-2015, 01:36 AM
#15
Registered
The best route to go will depend on what you want not only now, but in the future. You have to be honest with yourself. You may only want 550 hp now, but what about in a year or 2. Most guys get a taste of a little more power and speed and want more. It's like crack. The reason that I say to be honest, is that intake is going to be the limiting factor. You can only squeeze about 525-550 without extruding honing and shortening the runners in the intake. You will also need to bore the throttle body. Those mods will run about $1300-$1400. You will still be limited to about 600-625 hp. That is all that intake will support, whether its a 540-555 ci or not. That is the limit of the intake. So, if you think you only want 550 hp today, but think that there may be a chance that you want 650 next year, or the year after, then modifying that intake isn't the answer. You will need to replace the intake at that point. It doesn't make sense to dump that much money into that intake if it isn't going to get you where you want to be because you sure won't get that money back. You would be better served putting that money toward an intake like the Holley single plane. You can get the entire setup, minus electronics, for about $2500. That includes the intake, fuel rails, injectors, 2000 cfm throttle body, and sensors (TPS, IAT, IAC, ECT, MAP). You can use your Mefi ecm to run it. Even though your harness could be modified to work, you would be better off replacing it.
This is a mod that we have done countless times. Now you will have an intake without any limits for the future. We have used them on NA 598 ci to make near 800 hp so they will certainly do what you want. And they look and work great doing it.
Eddie
This is a mod that we have done countless times. Now you will have an intake without any limits for the future. We have used them on NA 598 ci to make near 800 hp so they will certainly do what you want. And they look and work great doing it.
Eddie
Last edited by Young Performance; 06-21-2015 at 01:38 AM.
06-23-2015, 07:45 PM
#16
Registered
Thread Starter
The best route to go will depend on what you want not only now, but in the future. You have to be honest with yourself. You may only want 550 hp now, but what about in a year or 2. Most guys get a taste of a little more power and speed and want more. It's like crack. The reason that I say to be honest, is that intake is going to be the limiting factor. You can only squeeze about 525-550 without extruding honing and shortening the runners in the intake. You will also need to bore the throttle body. Those mods will run about $1300-$1400. You will still be limited to about 600-625 hp. That is all that intake will support, whether its a 540-555 ci or not. That is the limit of the intake. So, if you think you only want 550 hp today, but think that there may be a chance that you want 650 next year, or the year after, then modifying that intake isn't the answer. You will need to replace the intake at that point. It doesn't make sense to dump that much money into that intake if it isn't going to get you where you want to be because you sure won't get that money back. You would be better served putting that money toward an intake like the Holley single plane. You can get the entire setup, minus electronics, for about $2500. That includes the intake, fuel rails, injectors, 2000 cfm throttle body, and sensors (TPS, IAT, IAC, ECT, MAP). You can use your Mefi ecm to run it. Even though your harness could be modified to work, you would be better off replacing it.
This is a mod that we have done countless times. Now you will have an intake without any limits for the future. We have used them on NA 598 ci to make near 800 hp so they will certainly do what you want. And they look and work great doing it.
Eddie
This is a mod that we have done countless times. Now you will have an intake without any limits for the future. We have used them on NA 598 ci to make near 800 hp so they will certainly do what you want. And they look and work great doing it.
Eddie
This very well explains what I wondered about and I agree that planning for the long haul is money well spent. You are right about wanting more power; it is addictive. So before I piddle with these intakes I will plan for the long haul because I will probably want to stroke them like I did my 242LS and like my 357 SR1 is.
Thanks for the explanation and info and I am glad your not far from me.
