Supercharger help
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Supercharger help
I have a Scarab with a stock 502 mpi. Looking hard at putting a 5 psi supercharger on it. One problem is there is no marina here with premium fuel,only 87 octane. Does anyone have any advice? Short of putting a bigger engine I thought the charger is the only way to go. Just want to go fast! Oh ya Whipple says 92 or higher only! I can't see all those boats out there running premium gas!
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I only run 93 in mine. I do have several bottles of this I keep on board in the event I can only find 89:
ValvTect Octane Performance Improver
http://www.valvtect.com/marineGasAdditives.asp
As a general rule I will not use 87 in my boat. Not worth the risk.
ValvTect Octane Performance Improver
http://www.valvtect.com/marineGasAdditives.asp
As a general rule I will not use 87 in my boat. Not worth the risk.
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http://www.manhattanoil.com/octane-boosters.php
The 2-1 racing formula.
Last edited by rgrgoog; 08-07-2011 at 05:20 PM.
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502mpi running M1 Procharger @ 7psi i only run 93 if they dont have it I put on the trailer till I find it. Its not worth the risk at all IMO. Oh and my 502 is all stock except for the entire fuel system and ecm update and the procharger. Runs like a beast and knock on wood been on the lake all summer long and no problems .
Last edited by swan2; 08-08-2011 at 09:54 AM.
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forced induction
I wouldnt reccomend running any boost into that engine with lower octane fuel unless an aftermarket engine management system is installed. The factory system installed on your MPI only utilizes a 1 bar map sensor and cannot sense a load under boost, therefore you have to use piggyback boxes for the ignition and fuel to "cheat" the engine into believing its still operating under a vacuum. Those systems in my experience are extremely unreliable and prone to tuning mistakes and problems, in fact most tuners will steer away from playing with them. Your best bet would be to sell your complete MPI and build a new engine with low compression, aftermarket EFI/DFI and a whipple setup. OR go carbed with 7.5:1 compression and low boost... Or just pull it out of the water and put 93 in it like we all do!
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I wouldnt reccomend running any boost into that engine with lower octane fuel unless an aftermarket engine management system is installed. The factory system installed on your MPI only utilizes a 1 bar map sensor and cannot sense a load under boost, therefore you have to use piggyback boxes for the ignition and fuel to "cheat" the engine into believing its still operating under a vacuum. Those systems in my experience are extremely unreliable and prone to tuning mistakes and problems, in fact most tuners will steer away from playing with them. Your best bet would be to sell your complete MPI and build a new engine with low compression, aftermarket EFI/DFI and a whipple setup. OR go carbed with 7.5:1 compression and low boost... Or just pull it out of the water and put 93 in it like we all do!