GPI intake manifold

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Jan 18, 2026 | 02:40 PM

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Racer

Joined: Jul 2014

Posts: 483

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From: Long Island, NY

GPI intake manifold

I was looking into the ported rod-mod from GPI for my ls3 intake manifold. Would it be beneficial for my 2011 Grand Sport with the only mods being 1-7/8 headers and Borla Atack exhaust?

Jan 18, 2026 | 07:56 PM

jamieo

Melting Slicks

Joined: Oct 2010

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From: Tollesboro Kentucky

I did the rod-mod intake with no porting and got 12HP and torque through the complete range,Same dyno and same day.

Jan 18, 2026 | 08:24 PM

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Racer

Joined: Jul 2014

Posts: 483

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From: Long Island, NY

Do you have any other modifications?

Jan 19, 2026 | 06:04 PM

jamieo

Melting Slicks

Joined: Oct 2010

Posts: 3,024

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From: Tollesboro Kentucky

Same exhaust system as you,Small BTR cam but you will still see gains without an upgraded cam.I am sure GPI could tell you exactly what to expect.

Jan 19, 2026 | 06:36 PM

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Racer

Joined: Jul 2014

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From: Long Island, NY

Thanks for the information!

Feb 1, 2026 | 08:31 AM

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Racer

Joined: Jul 2014

Posts: 483

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From: Long Island, NY

I'm sure you didn't notice the gains but was there a difference in throttle response. Increased throttle response, any bogging off the line?

Feb 1, 2026 | 04:04 PM

jamieo

Melting Slicks

Joined: Oct 2010

Posts: 3,024

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From: Tollesboro Kentucky

No bogging at all.Already had a ported throttle body so tip-in and throttle response was addressed there.I THINK it pulls a little better and stronger but not anything amazing.Don't honestly know it I could have saw any difference without the dyno numbers to back it up.Would I do it again?Absolutely!!