mpi and efi intakes?
09-20-2016, 03:34 PM
#31
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Update on this engine, I got it up to 642 HP at 5800 rpm with a lot of tuning and pulling some water out of the exhaust which seemed to be holding it back a little on top.
09-29-2016, 08:25 AM
#32
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Arcticfriends - looks like Jwurl and MER went thru this very thing with 500EFI intakes and then aftermarket 2000cfm tbody on Edelbrock carb type efi manifold.
They had done the tbody on 500EFI intake that Crockett does.
Post #340 here: http://www.offshoreonly.com/forums/g...ml#post4166342
and
They had done the tbody on 500EFI intake that Crockett does.
Post #340 here: http://www.offshoreonly.com/forums/g...ml#post4166342
and
My advise to you is ditch the MEFI system. The 500 EFI manifold is not as bad as everyone seems to think. I built a modified 540 EFI and had the stock 500 efi intake assy. with the top mount Tyler Crockett throttle body kit. This engine was 693 Hp at 6000rpm on the dyno. I had the same engine refreshed after 20 hours run time and switched to a Holley EFI system with an Edelbrock intake. This motor is 714 HP. Identical motor except the intake and injection system. So the 500 EFI intake costs roughly 25 HP on a 700hp engine. Mefi system is nothing but a headache. Not being able to tune anything yourself is a joke. My mefi system was always rich or not running right in some shape or form. With the Holley system you just put in the o2 sensor and it basically tunes itself. . Sending a mefi ecm back and forth for tuning gets old. Since switching to the Holley System the boat runs night and day different. It is worth every penny and selling your old system with net you half the cost of a Holley system. Call Mark at MER performance and get some real numbers from him. He has done both my motors and just got done doing a set of motors with ported stock 525 intakes and larger throttle bodies with the Holley Injection installed on them. Jeff Wurl
Last edited by SB; 09-29-2016 at 08:37 AM.
09-29-2016, 08:52 AM
#33
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[QUOTE=SB;4486150]Arcticfriends - looks like Jwurl and MER went thru this very thing with 500EFI intakes and then aftermarket 2000cfm tbody on Edelbrock carb type efi manifold.
They had done the tbody on 500EFI intake that Crockett does.
Post #340
They could have gotten much further IF they had bought mefiburn and were able to tune it on dyno, i made HUNDREDS of changes while tuning my last mpi on dyno, on something that modified i cant see a canned tune being ideal. Im also doing runner length changes in steps, will post data when i get started, Smitty
They had done the tbody on 500EFI intake that Crockett does.
Post #340
They could have gotten much further IF they had bought mefiburn and were able to tune it on dyno, i made HUNDREDS of changes while tuning my last mpi on dyno, on something that modified i cant see a canned tune being ideal. Im also doing runner length changes in steps, will post data when i get started, Smitty
09-29-2016, 08:57 AM
#34
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Arcticfriends - looks like Jwurl and MER went thru this very thing with 500EFI intakes and then aftermarket 2000cfm tbody on Edelbrock carb type efi manifold.
They had done the tbody on 500EFI intake that Crockett does.
Post #340 here: http://www.offshoreonly.com/forums/g...ml#post4166342
and
They had done the tbody on 500EFI intake that Crockett does.
Post #340 here: http://www.offshoreonly.com/forums/g...ml#post4166342
and
https://www.tpis.com/parts/view/269
09-29-2016, 04:16 PM
#35
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To add a little more to this thread. A few years ago I built a nice 598. Just to experiment, I used a 500 efi base and built a sheet metal top with 4 2bbl throttle bodies. Torque was fantastic but it pretty much quit at 5400 rpm, making 730 HP. I switched it out to a dart tunnel ram with the 4 2bbl throttle bodies on it and made 800 HP at 6000 rpm. No other changes. Lost a lot of torque down low though. I actually had to drop down an inch in pitch to get it out of the hole satisfactorily. But gained 4 mph on top.
Bob
Bob
09-29-2016, 04:32 PM
#36
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I know where theres a pair of low low hour 525 intakes,TB's fuel rails and injectors, no pcm's or wiring 
11-03-2016, 02:23 PM
#37
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Hey guys,
I don't mean to hyjack the thread but my questions are in regards to the intake on my motor. From what I've read so far in this thread, the 500efi intake tops out making power around 5200rpm and can be restrictive on air flow when trying to upgrade performance on an engine build. Over this past winter I had my 500efi completely rebuilt, including being bored over to 516cube stemming from a previous owner having the engine rebuilt and bored to a 509 after valve failure. I had to bore again due to the previous work not taking enough material to correct the scoring on the cylinder walls. dart pro 1 heads, larger cam(don't know the specs) and balanced and blue printed bottom end. The engine dynoed at 585 hp at 5300rpm peak and 640 ft lbs of torque at 4000rpm peak. I was told I could build more power at a higher rpm, but my original 500efi intake was restricting that. I was told the 500efi intake builds lots of torque vs the 525 intake which is better at building HP. It was explained to me that 500efi has longer channels/ guides where as the 525 intake has shorter ones. Would I benefit if I could get a 525 intake? Would it be worth it? What would I gain in HP and how much would one cost and also to install?
I don't mean to hyjack the thread but my questions are in regards to the intake on my motor. From what I've read so far in this thread, the 500efi intake tops out making power around 5200rpm and can be restrictive on air flow when trying to upgrade performance on an engine build. Over this past winter I had my 500efi completely rebuilt, including being bored over to 516cube stemming from a previous owner having the engine rebuilt and bored to a 509 after valve failure. I had to bore again due to the previous work not taking enough material to correct the scoring on the cylinder walls. dart pro 1 heads, larger cam(don't know the specs) and balanced and blue printed bottom end. The engine dynoed at 585 hp at 5300rpm peak and 640 ft lbs of torque at 4000rpm peak. I was told I could build more power at a higher rpm, but my original 500efi intake was restricting that. I was told the 500efi intake builds lots of torque vs the 525 intake which is better at building HP. It was explained to me that 500efi has longer channels/ guides where as the 525 intake has shorter ones. Would I benefit if I could get a 525 intake? Would it be worth it? What would I gain in HP and how much would one cost and also to install?
11-03-2016, 03:01 PM
#38
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With all things the same besides changing out the intake, dont think you will see any gains, who reflashed your ecm ??
