2011 Mustang GT - 7700RPM Power Drop Off

[EQ Tuning]

I'm working on a built 2011 GT and running into an odd issue. The car has a built block, GT350 heads, 2018 manifold, headers, intake, 85mm throttle body, 47# injectors, etc.

I got everything running nicely but we get a consistent sharp power drop at anything over ~7600RPM. I already applied the rev limiter patch as instructed and I don't believe this is an actual rev limiter. The throttle stays open, timing stays on target, injectors are not being cut and if you drive through it, it will get to 8000RPM+ very slowly. The dyno chart nosedives almost like a rev limit and airflow definitely falls off as well. My only guess is valve float, but that shouldn't be the case with these heads?

Any thoughts or suggestions?

Thanks
-- Ed

[paulsmithsr]

Cobra jet intake

[Cranked Automotive]

I agree with above ^

[Danielerevia]

Agree with above also what cams?

[blackbolt22]

What cams does it have? I hope they aren't stock cams O.o. Show us the dyno chart.

[aaronson]

Cobrajet like everyone else said and for cams Comp NA stage 2 or 3, or contact L&M enignes and ask for their suggestion. I prefer L&M because the make cams from fully functional VCT all the way to fully Locked. Plus they give you suggested VCT bracketing values to build a base tune with. Also im sure you know but make sure the cams you get are compatible with the timing compenents.

[aaronson]

I would also suggest a stock throttle body. Theres really not need to upgrade and they usually cause way more issues then hp

[murfie]

You said cobra jet then stock throttle body? When trying to make power above 7700RPM? The massive oval cobrajet throttle body is half the reason why it out flows the GT350 and 2018+ manifolds, and always will.

[Robert00MustangTurbo]

Here's a dyno graph on my 2012 Mustang GT with 174XXX miles with the following modifications:

2012 Mustang GT M6

Ported Cobra Jet Manifold
D-Mark Cold Air Intake
VMP 137 Monoblade
BBK Cat Deletes
FRPP LU47 Injectors
E85


Check out the graph below. Tested on my Land and Sea DYNOmite Dynamometer 20".

Testing both manifolds

You can see the power Difference between the two manifolds and where the 2018+ manifold just absolutely eats it above 7200RPMS compared to the Cobra Jet Manifold where it can carry all the way out to almost 8000RPMS, with STOCK GEN 1 CAMS.

Even with the GT350 Cylinder heads, you're choking the engine out in the upper power band with the 2018+ Manifold. Get a Cobra Jet.

123596493_388297042526589_1874755610946105336_n.png

[aaronson]

I was meaning stock throttle body with his current setup. The 18' manifold. sorry for the confusion