502 MPI build up
12-01-2018 | 07:52 AM
#31
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Joined: Jun 2004
Posts: 7,317
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From: frankenmuth michigan
The tpis tb leaned motor out from 4500 up, especially from 5200/5400 up, picks up about 8 to 10 on a stocker 502, closer to 15 on a modded 502 or 540. If you bolt a gen6 fa or pos hardin/rex marine fa on it kills hp. Also took map at top from 92/94 to 97 ish. The rex marine adapter killed so much fliw even wo the element on it drove tune into low 90 map and sub 500hp from the 540 ish i was at at the time. Ive seen 540s w 502 mpi intakes w stock tbs and crappy fa pick up 2 to 4 mph in a boat, guys have to look at big picture. All the cu inches, cam, heads in world cant do much if motors choked off
12-01-2018 | 02:53 PM
#32
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Joined: Nov 2013
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From: Baltic Sea
Seems like all over 4500 the TB is too small. But you are right, all parts wich flow air have to be calculated to fit together.
At this time i will go with the old FA, 68mm TB, worked intake, better cam, reprogramed ecu, better pistons and stainless marine exhaust with o2 sensor.
I‘m actual not sure if i should go 540 and new bigger heads.
At this time i will go with the old FA, 68mm TB, worked intake, better cam, reprogramed ecu, better pistons and stainless marine exhaust with o2 sensor.
I‘m actual not sure if i should go 540 and new bigger heads.
02-28-2019 | 11:43 AM
#33
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From: Baltic Sea
The old heads look too wasted to re use them. I get some Dart Pro 1 heads.
How would you go forward, with 509 or a cast 540 set. A cast 540 set would only be a few hundrets more that the stock 509, but cast....
I´m going to order the Crane 168741, will the stainless marine exhaust work without reversion or do i need another exhaust system? I had the stainless marine exhaust for 14 years of saltwater operation, the stainless steal riser are ok, i only need the lower parts. But if there could be reversion i would go with anything other. I drive switchable silencer endtips. I may not make too much noise in my harbor and due to the stellings extension box i do not have an under water exhaust through the drive.
How would you go forward, with 509 or a cast 540 set. A cast 540 set would only be a few hundrets more that the stock 509, but cast....
I´m going to order the Crane 168741, will the stainless marine exhaust work without reversion or do i need another exhaust system? I had the stainless marine exhaust for 14 years of saltwater operation, the stainless steal riser are ok, i only need the lower parts. But if there could be reversion i would go with anything other. I drive switchable silencer endtips. I may not make too much noise in my harbor and due to the stellings extension box i do not have an under water exhaust through the drive.
02-28-2019 | 05:07 PM
#34
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Joined: Jan 2006
Posts: 3,865
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From: St. Pete Beach, FL
I bought some 1 7/8 vette headers to try, thinking they will bump bump up tq close to what manifolds made and knock off some top end hp, if they dont, ill buy some other ones. Its a big pia for me to run wet exhaust, we killed a 02 sensor w the Eddie manifolds too. Trying to find something thats as close as possible to numbers manifold made.
