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Originally Posted by MILD THUNDER
(Post 3851242)
With its low compression, I don't see why 7lbs, maybe even 8lbs with that 871 non intercooled, with better headgaskets. I bet the 871 is making less heat at 7lbs than the 256 was at 4.5 lbs.
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Originally Posted by 4bus
(Post 3851633)
In the process right now. Following precision marine's set up (pmefi.com) Same 575 story-
full roller conversion 3.5 pulley ECU reflash 120 degree stat plumbing for chillers but going to test without to start. My objective was to improve more than it was to add speed. I thought the boat performed well on top stock, and was very reliable. My issues were idle, loading up, soot/extreme richness, and known HG failures. The cam change was a give in, seeing that we had the heads off. I have to say if I did not read oso I most likely would have left them in and just did an ecu and pulley.....the talk on this site scared me into tearing the heads and cams out of engines with 60 hrs! My engines and boat also sat for 8 years, showing only 3 hrs on the ecus. Builder saw signs of spring fatigue on a few valves and the edge of an intake lifter was missing tiny pieces and marked the cam. Lower end is perfect. Man I ramble.......sorry, back to the OP :lolhit: |
Originally Posted by mcprodesign
(Post 3851655)
Do you think temp on an intercooled 250 is similar to a non intercooled 871 @ 7lbs? Thanks for the input
I have never seen a test on a typical "superchiller'' style intercooler, providing temperature data or efficiency numbers. I know if I was manufacturing a product and selling it, I would provide those numbers, especially if they were worth talking about. I am also not aware, of anyone adding a superchiller, keeping the same boost level, and netting mph gains anywhere near what the OP did, or myself, from stepping up to a larger blower. Sure, adding a chiller AND upping the boost, has netted speed gains, but then again, it should. Boost is HP. |
I am running 6-7 lbs on my new DMPE rebuilt blowers without chillers. Running aftermarket aluminum heads though. Eddie @ Young Performance got me some nice custom ground roller cams. This combo is perfect.
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Originally Posted by keegan
(Post 3851765)
I am running 6-7 lbs on my new DMPE rebuilt blowers without chillers. Running aftermarket aluminum heads though. Eddie @ Young Performance got me some nice custom ground roller cams. This combo is perfect.
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Originally Posted by TRL505
(Post 3851750)
What speeds were you seeing when stock?
I am hoping to see a real 5 mph gain from my mods with out a prop change or chiller, then go from there. I am running the plumbing for the chillers but waiting on the install. I want to get spring run numbers, then summer heat numbers first. I will then add the chillers in the heat of the summer and see there is a a change. I will also monitor the knock sensor activity with and without chillers. This is my plan, we will see if I have the same desire this summer. |
Originally Posted by 4bus
(Post 3851865)
Runs a consistent 88 mph in the summer heat. Cooler days it has broke 90. Last run of last year with water and air temps in the 50's it did 92.7 on the limiters. I wish it ran like that every day. The thought is chiller would give these engines cold weather performance year round???
I am hoping to see a real 5 mph gain from my mods with out a prop change or chiller, then go from there. I am running the plumbing for the chillers but waiting on the install. I want to get spring run numbers, then summer heat numbers first. I will then add the chillers in the heat of the summer and see there is a a change. I will also monitor the knock sensor activity with and without chillers. This is my plan, we will see if I have the same desire this summer. |
Originally Posted by 4bus
(Post 3851865)
Runs a consistent 88 mph in the summer heat. Cooler days it has broke 90. Last run of last year with water and air temps in the 50's it did 92.7 on the limiters. I wish it ran like that every day. The thought is chiller would give these engines cold weather performance year round???
I am hoping to see a real 5 mph gain from my mods with out a prop change or chiller, then go from there. I am running the plumbing for the chillers but waiting on the install. I want to get spring run numbers, then summer heat numbers first. I will then add the chillers in the heat of the summer and see there is a a change. I will also monitor the knock sensor activity with and without chillers. This is my plan, we will see if I have the same desire this summer. |
Originally Posted by 4bus
(Post 3851865)
Runs a consistent 88 mph in the summer heat. Cooler days it has broke 90. Last run of last year with water and air temps in the 50's it did 92.7 on the limiters. I wish it ran like that every day. The thought is chiller would give these engines cold weather performance year round???
I am hoping to see a real 5 mph gain from my mods with out a prop change or chiller, then go from there. I am running the plumbing for the chillers but waiting on the install. I want to get spring run numbers, then summer heat numbers first. I will then add the chillers in the heat of the summer and see there is a a change. I will also monitor the knock sensor activity with and without chillers. This is my plan, we will see if I have the same desire this summer. |
Originally Posted by TRL505
(Post 3852024)
Do it!!!!:evilb:
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