Square top and BP5A cam = 13rwhp loss
08-28-2018, 01:26 PM
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Square top and BP5A cam = 13rwhp loss
Went from 202rwhp to 189 rwhp after installing square top and BP5A cam. Also installed egr block off and coolant reroute but that shouldn't have affected anything.
I've read the msm cam gear is timed different. Would an adjustable cam get help me gain the power back? Any other ideas I should pursue?
I've read the msm cam gear is timed different. Would an adjustable cam get help me gain the power back? Any other ideas I should pursue?
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08-28-2018, 02:51 PM
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13 hp lost was discovered after dyno tuning and comparing with last dyno tune.
Approximately about 1k miles between tune.
94 Miata, bp4w head, mp62, 84.5mm 9:1 pistons
borla exhaust, no cat
Approximately about 1k miles between tune.
94 Miata, bp4w head, mp62, 84.5mm 9:1 pistons
borla exhaust, no cat
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08-29-2018, 12:53 PM
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Manifold pressure increased from 5-7k compared to last session (no change to supercharger setup)
Fuel was 8-10% richer in the midrange to redline
Adding and pulling fuel and timing resulted in negligible improvements
Fuel was 8-10% richer in the midrange to redline
Adding and pulling fuel and timing resulted in negligible improvements
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08-29-2018, 04:37 PM
#15
Agreed. I would expect to see a boost pressure DECREASE. The blower is going to try to move the same amount of air per revolution, no matter what.. so if pressure increases that means either restriction has been removed on intake side of the BLOWER, or added on the exhaust side of the blower - which is the engine..
And verifying timing in this case means find out where 0deg is on the stock cam lobe... compare to new cam, could have some advance/retard ground in. Cheaper/quicker way is throw on adjustable gear, make adjustments on dyno, which you'd want to do anyway.
And verifying timing in this case means find out where 0deg is on the stock cam lobe... compare to new cam, could have some advance/retard ground in. Cheaper/quicker way is throw on adjustable gear, make adjustments on dyno, which you'd want to do anyway.
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08-29-2018, 05:10 PM
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I ordered an adjustable cam gear as soon as I got off the dyno. Should be here Friday.
Just not sure if he'll be able to squeeze me in for more dyno time anytime soon.
Will a few degree adjustment potentially gain 13+ hp?
Just not sure if he'll be able to squeeze me in for more dyno time anytime soon.
Will a few degree adjustment potentially gain 13+ hp?
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08-29-2018, 08:17 PM
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If you lost 13whp, it's broken. Throwing more parts at it is not going to fix it, it will just mask whatever you broke. You added a cam with more duration and lift, and an intake manifold proven to show less high-RPM restriction in other applications, and you saw an increase in intake restriction (more boost at same blower speed). That's totally illogical and it indicates an additional external variable which you have not accounted for. That variable is likely something along the lines of "the cam is installed one tooth advanced". You can advance the intake cam up to two full teeth, and the car will run fine, aside from making poor high-RPM power.
The increase in MAP pressure should have set your alarm bells ringing. You should have seen the opposite.
You are operating on the assumption that your 13rwhp loss is the appropriate result for the changes that were made. I think that assumption is a poor one.
The increase in MAP pressure should have set your alarm bells ringing. You should have seen the opposite.
You are operating on the assumption that your 13rwhp loss is the appropriate result for the changes that were made. I think that assumption is a poor one.
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