How much hp is the stock pump good for?
05-12-2010, 12:14 PM
#1
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How much hp is the stock pump good for?
On my budget build, I plan to run about 10psi max on the small t25. So i estimate about 200whp. Is the stock fuel pump able to support this. And maybe plan to run e85 so about 20%more fuel needed. I'm seeing some guys run stock pumps on 250hp miatas, is this safe
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05-12-2010, 02:57 PM
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4 High pressure fuel pump
The stock Miata fuel pump can only provide so much fuel (tends to max out around 85psi). And we have already discussed the potential of higher fuel pressures versus higher horsepower. So you need to upgrade the pump if you plan to fuel past 70-80psi; usualy due to running small injectors on an FMU setup. Raising the fuel pressure raises the size of the injectors. Since it requires an aftermarket fueling device to control +20/30% larger injectors, adding more fuel pressure is the logical solution.
Other than that, you don't need one. If you have an aftermarket ECU, the stock pump more than enough to support 300rwhp with the stock regulator. Changing the fuel pump does nothing but flow enough fuel...it doesn't change any other factors in the fuel entering the combustion chamber.
The stock Miata fuel pump can only provide so much fuel (tends to max out around 85psi). And we have already discussed the potential of higher fuel pressures versus higher horsepower. So you need to upgrade the pump if you plan to fuel past 70-80psi; usualy due to running small injectors on an FMU setup. Raising the fuel pressure raises the size of the injectors. Since it requires an aftermarket fueling device to control +20/30% larger injectors, adding more fuel pressure is the logical solution.
Other than that, you don't need one. If you have an aftermarket ECU, the stock pump more than enough to support 300rwhp with the stock regulator. Changing the fuel pump does nothing but flow enough fuel...it doesn't change any other factors in the fuel entering the combustion chamber.
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05-13-2010, 11:39 AM
#10
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At about 260 rwhp, my stock pump was starting to run out of steam above 6000 RPM. Datalogs showed it running leaner than target AFR, and adding injector ontime made little difference, so out it came.
--Ian
--Ian
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05-14-2010, 11:31 AM
#11
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New, I think it's well agreed that the stock pump can fuel enough for almost 300 whp, but with many of us running around with cars that are now boosted but were made back in the early 90's, it's quite possible the stock pump is old and limping.
-Ryan
-Ryan
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