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-   -   Square top and BP5A cam = 13rwhp loss (https://www.miataturbo.net/engine-performance-56/square-top-bp5a-cam-%3D-13rwhp-loss-97903/)

Halcyon 08-28-2018 01:26 PM

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?

matrussell122 08-28-2018 01:34 PM

Have you done any tuning after changing the intake and cam

concealer404 08-28-2018 01:35 PM

What is the car/setup in question?

18psi 08-28-2018 01:53 PM


Originally Posted by matrussell122 (Post 1498840)
Have you done any tuning after changing the intake and cam

+1

ryansmoneypit 08-28-2018 02:21 PM

how many miles / time between dyno test?

Stealth97 08-28-2018 02:22 PM

Verify cam timing!

Halcyon 08-28-2018 02:51 PM

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

Halcyon 08-28-2018 02:59 PM


Originally Posted by Stealth97 (Post 1498853)
Verify cam timing!

Maybe I'm off a tooth? I'll double check.

18psi 08-28-2018 03:58 PM

definitely sounds like something is wrong/broken

Stealth97 08-28-2018 04:57 PM


Originally Posted by Halcyon (Post 1498857)
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

I missed the mp62 part...

Did boost pressure change? more boost = more restriction.. Did fuel have to be added? or taken away?..

sixshooter 08-29-2018 07:14 AM

404 Data not found

Halcyon 08-29-2018 12:53 PM

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

concealer404 08-29-2018 12:55 PM

It sounds like something is mechanically wrong... I would have expected the opposite at high rpm.

sixshooter 08-29-2018 02:52 PM

Sounds like cam timing.

Stealth97 08-29-2018 04:37 PM


Originally Posted by sixshooter (Post 1499055)
Sounds like cam timing.

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.

Halcyon 08-29-2018 05:10 PM

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?
​​​​​

concealer404 08-29-2018 05:28 PM

If it's wrong now and you fix it? Sure.

sixshooter 08-29-2018 05:53 PM


Originally Posted by Halcyon (Post 1499075)
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?
​​​​​

Easily.

Savington 08-29-2018 08:17 PM

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.

Halcyon 08-29-2018 08:20 PM

Thanks for the input.

I'll check the timing.


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