C7 Corvette ZR1 Cold Air Intake: Before and After Dyno Numbers

Corvette ZR1 picked up 6 horsepower and 22 lb-ft of torque at the wheels with the GMPP cold air intake.

It is a popular point of discussion as to whether cars like the C7 Chevrolet Corvette ZR1 can benefit enough from a cold air intake to justify the cost. With many vehicles, a cold air intake offers very little real world power improvement, but with the kit from GM Performance Parts promising a 17-horsepower gain, the $625 list price doesn’t seem so bad.

At the same time, some people question the claims of 17 horsepower being added to the C7 ZR1, so “.gearhead.” recently purchased one of these intake kits and headed to his local dyno shop to test the real world gains. As mentioned above, this kit does offer better numbers, but they are not as high as GM claims.

Corvette ZR1 CAI Testing

When the OP shared his findings with the forum, he included a picture of his gorgeous Corvette ZR1 strapped down to the dyno, followed by the dyno sheet with before and after numbers.

I don’t see many dyno posts so I thought I’d post mine. We did a baseline run in bone stock trim and a run with the GMPP CAI installed. Car has 1700 miles on it. Air temperature was in the low 80’s.

Before: 660 HP / 657 TQ
After: 666 HP / 679 TQ
Gains: +6 HP / +22 TQ

As you likely know, the new ZR1 has official power figures of 755 horsepower and 715 lb-ft of torque, but those measurements are taken at the crankshaft. By the time the engine turns the driveshaft, the transmission, the differential, the axles and the wheels, it “loses” 95 horsepower and 58 lb-ft of torque.

However, as we can see in the included dyno sheet, the GMPP cold air intake tacks on 6 horsepower and 22 lb-ft of torque at the rear wheels. That is short of the 17-horsepower advertised gains, but that is a nice torque increase with a little extra horsepower.

The Community Chimes In

The first person to offer a detailed reply to this information was “TheRobSJ”, who pointed out some key points on the dyno graph.

Yeah I shoulda known that GM’s claim of 17hp was a lie.

What is very interesting is that you pick up some power from 4250 to 5300, but then you actually lose power from 5300 to about 6250? A pretty decent chunk of power too. But then it comes back for the peak just before redline.

In the end, that bump from 4250 to 5300 makes the airbox worth it. Most people probably spend more time there driving it hard than really wringing it out pulling all the way to the fuel cut.

While “Jam421” talked about where the differences occurred in the power band.

My interest is in looking at the shape of the power curve. I’m sure on a road course more HP/TQ between 4300-5300 would feel great. But in a straight line race with the motor or manual driver shifting around 63-6500rpm it will land right where the new airbox loses significant HP. We’ve all been in races where a guy seems to pull 2-3 feet up top…after each shift…somehow after a few gears he’s out by a car.

Haven’t some videos shown the locked out ECU positively adapted to changes after a series of 3-4 pulls? The different shapes/dips of red vs blue lines seems like the motor is screaming for an AFR tweak. Just wondering if after 3-4 dyno pulls the ECU would’ve made that adjustment. Or….after a few open road stabs if the ECU takes back that significant 43-5300rpm HP loss. If the ECU smoothed out the AFR it may lift both TQ/ HP curve power curve above stock thru the entire power band. A tuner with more expertise might say ” let me at that ECU !” LOL. In the meantime maybe even the Butt Dyno might feel the ECU tweaking for change after 3-4 back to back straight line highway pulls.

And of course, someone had to question the results, and in this thread, that person was “Sub Driver”.

I don’t think this is a very good representation to prove anything. You are losing close to 40hp around 5500rpm. To accurately say this CAI provided xx amount of hp you would need to do some more dyno runs before and after since these have some pretty odd deltas.

To which the OP replied with a basic disclaimer of sorts, following up by pointing out that he doesn’t feel the extra power.

Made five pulls. This is simply one example, one point of reference. Results may vary…

I don’t really feel a seat of the pants difference, to be honest. I did a CAI just to see if the claims were accurate. I tried them on a lot of cars and never was much of a believer. The real mods will be fun.

If you want to participate in the discussion on power gains from the C7 Corvette ZR1, click here to head into the forum.

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