Jackson Racing C38-81 Supercharger - CARB legal - Page 13 - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

Bykov · 04-18-2016, 08:38 PM

Quote:

Originally Posted by byun

I'm pretty much at sea level. Wasn't able to get a baseline. Ended up with 236whp mods are JRSC c38 w/ ace header 250 and greddy supreme sp catback.

I think a stock brz on there dyno is around 135-140whp

Based on your gains you are getting exactly as advertised power. Are you on the stock MAP sensor? If you are that probably explains it. It loses resolution after 5 psi I hear. Maybe you are losing boost pressure due to some valve overlap?

byun · 04-18-2016, 08:43 PM

Quote:

Originally Posted by Bykov

Based on your gains you are getting exactly as advertised power. Are you on the stock MAP sensor? If you are that probably explains it. It loses resolution after 5 psi I hear. Maybe you are losing boost pressure due to some valve overlap?

Nope, we upgraded the map sensor. We checked intercooler piping and all hoses that could cause a leak. Everything checks out. Car runs strong, just not getting up to 9psi.

byun · 04-18-2016, 10:40 PM

Figured of the issue. The bypass valve doesn't hold the boost past 7psi.

Had a turbo smart bpv that I had from another car so threw it in and boost is now 9-9.5psi

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Hicklinc · 04-18-2016, 10:43 PM

Was thinking that was low with that header

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SoCalArgento · 04-19-2016, 01:27 AM

Quote:

Originally Posted by byun

Figured of the issue. The bypass valve doesn't hold the boost past 7psi.

Had a turbo smart bpv that I had from another car so threw it in and boost is now 9-9.5psi

Sent from my iPhone using Tapatalk

Wait so the C38 bypass valve won't hold over 7psi?
Meaning it's restricting potential power at 9psi or did I misunderstand?

Hicklinc · 04-19-2016, 01:29 AM

Quote:

Originally Posted by SoCalArgento

Wait so the C38 bypass valve won't hold over 7psi?
Meaning it's restricting potential power at 9psi or did I misunderstand?

My guess would be a faulty unit but I would also like the answer to this

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byun · 04-19-2016, 09:46 AM

Guessing it's just a faulty BPV. I'm sure others are working fine and holding past 7psi.

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johan · 04-19-2016, 11:56 AM

It's pretty common for those BPVs to fail. They're some cheap Volkswagen crap that JR/KW use on all their kits. Upgrading to a metal unit from a reputable source is a common practice for Rotrex kits on other platforms.

CSG Mike · 04-19-2016, 12:20 PM

I would imagine I've seen more of these kits than anyone else, and I've yet to see a bypass from the JR kit fail without a good reason (e.g. bad removal on a used kit).

If for some reason yours DID fail (never say never), then @Jackson Racing will gladly replace your unit; their warranty is solid.

PandaSPUR · 04-19-2016, 12:39 PM

Quote:

Originally Posted by CSG Mike

I would imagine I've seen more of these kits than anyone else, and I've yet to see a bypass from the JR kit fail without a good reason (e.g. bad removal on a used kit).

If for some reason yours DID fail (never say never), then @Jackson Racing will gladly replace your unit; their warranty is solid.

I dont imagine theres any easy way to check for improper boost without a gauge or just noticing the loss of power, right?

byun · 04-19-2016, 12:39 PM

Quote:

Originally Posted by CSG Mike

I would imagine I've seen more of these kits than anyone else, and I've yet to see a bypass from the JR kit fail without a good reason (e.g. bad removal on a used kit).

If for some reason yours DID fail (never say never), then @Jackson Racing will gladly replace your unit; their warranty is solid.

My kit was purchased new and has a little over 1k miles on it. Still works just keeps me from hitting full boost.

byun · 04-19-2016, 12:43 PM

Quote:

Originally Posted by PandaSPUR

I dont imagine theres any easy way to check for improper boost without a gauge or just noticing the loss of power, right?

I have a boost gauge and also upgraded map sensor so I can see where i'm maxing out at in the logs.

also knew something was up when we were tuning and i was making about 20whp less than similar setups.

CSG Mike · 04-19-2016, 03:10 PM

Quote:

Originally Posted by PandaSPUR

I dont imagine theres any easy way to check for improper boost without a gauge or just noticing the loss of power, right?

You'd need a MAP sensor that can read boost past 20psi absolute, and a tune scaled to that MAP sensor.

Alternatively, an external boost gauge would also catch it.

Most people probably wouldn't notice the loss of power unless they had a fully functional, but identical car for comparison.

PandaSPUR · 04-19-2016, 04:36 PM

Quote:

Originally Posted by CSG Mike

You'd need a MAP sensor that can read boost past 20psi absolute, and a tune scaled to that MAP sensor.

Alternatively, an external boost gauge would also catch it.

Most people probably wouldn't notice the loss of power unless they had a fully functional, but identical car for comparison.

So would this be a good reason to get a boost gauge on a SC car then? I usually only see boost gauges in turbo cars.

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04-18-2016, 10:43 PM	#172
Hicklinc Member Join Date: Nov 2015 Drives: N/a Location: Kennesaw ga Posts: 45 Thanks: 407 Thanked 11 Times in 8 Posts Mentioned: 1 Post(s) Tagged: 2 Thread(s)	Was thinking that was low with that header Sent from my SM-N910T using Tapatalk

04-19-2016, 11:56 AM	#176
johan Senior Member Join Date: Aug 2014 Drives: '14 981CS, '99 NB1 Location: Oregon Posts: 1,274 Thanks: 1,234 Thanked 1,201 Times in 631 Posts Mentioned: 114 Post(s) Tagged: 2 Thread(s)	It's pretty common for those BPVs to fail. They're some cheap Volkswagen crap that JR/KW use on all their kits. Upgrading to a metal unit from a reputable source is a common practice for Rotrex kits on other platforms.

04-19-2016, 12:20 PM	#177
CSG Mike Join Date: Jul 2012 Drives: S2000 CR Location: Orange County Posts: 14,535 Thanks: 8,927 Thanked 14,181 Times in 6,837 Posts Mentioned: 966 Post(s) Tagged: 14 Thread(s)	I would imagine I've seen more of these kits than anyone else, and I've yet to see a bypass from the JR kit fail without a good reason (e.g. bad removal on a used kit). If for some reason yours DID fail (never say never), then @Jackson Racing will gladly replace your unit; their warranty is solid.

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