[h018871]

This subject has been discussed many times........I believe that in most occasions the wrong info has been reinforced. I had been following incorrect advice.

84154731 is the 2 piece track kit that has the small 'air dam' strips that go in front of the curved tire deflectors

84234055 is the 4 piece curved tire air deflectors, also includes bolts and a rivet.

84234055 should be run on the car during street driving and removed for the track. I suspect that these are for fuel mileage improvements
84154731 should be installed for track days and removed for street driving. Stated to reduce front end lift for better handling.

Most posts are indicating that the small pieces are thrown away and the curved pieces should be run all the time. A lesser number of posts show all 6 pieces installed (this probably comes from the performance driving supplement, the picture shows *4055 still on the car.

Looking at step 4 of the *4055 installation instructions, the one with the race track and checkered flag, show only the *4731 pieces installed in front of the tires.

[h018871]

Would someone with a ZLE measure the height of the chevron shaped air dam under the bumper in the front?
they are different part numbers and in the drawings, not always accurate, the ZLE one looks to be bigger

84114187 - (ZL1) DEFLECTOR,FRONT BUMPER FASCIA CENTER AIR, "chevron" rubber piece, # 44 of ZL1 drawing
84244390 - (ZLE) DEFLECTOR,FRONT BUMPER FASCIA CENTER AIR, "chevron" rubber piece, # 29 of ZLE drawing

The ZLE piece is approx 2x the price of the ZL1 piece, most likely due to volume.

[RUQWIKR]

Sent info already to you, but for all other's sake: ~1.25" tall (plus any material that has been worn down after lots of scraping) and 15.75" wide center to each wing end along surface.

[h018871]

Originally Posted by RUQWIKR

Sent info already to you, but for all other's sake: ~1.25" tall (plus any material that has been worn down after lots of scraping) and 15.75" wide center to each wing end along surface.

Thx,the ZL1 version is 18.5" on each wing and ~1" high with an unknown amount that has been scraped off

I did not expect a width difference, learn new things every day. The increased height will help to reduce air pressure under the car. It's something to consider.

[RUQWIKR]

Originally Posted by h018871

Thx,the ZL1 version is 18.5" on each wing and ~1" high with an unknown amount that has been scraped off

I did not expect a width difference, learn new things every day. The increased height will help to reduce air pressure under the car. It's something to consider.

Our info even matches the two parts imager pics if you look closely!

[JT Camaro]

soooo..whats the verdict?

[h018871]

Originally Posted by JT Camaro

soooo..whats the verdict?

84154731 should be run at the track, 84234055 should be run on the street under 'normal' circumstances, possibly giving better fuel efficiency.

The ZLE (84244390) lower air dam ~may~ provide better front stability by creating lower pressure under the front of the car at the track. Possibly at the cost of poorer fuel efficiency on the street.

[JT Camaro]

Originally Posted by h018871

84154731 should be run at the track, 84234055 should be run on the street under 'normal' circumstances, possibly giving better fuel efficiency.

The ZLE (84244390) lower air dam ~may~ provide better front stability by creating lower pressure under the front of the car at the track. Possibly at the cost of poorer fuel efficiency on the street.

Interesting, I always read the manual as pulling 84154731 off for track use

[h018871]

Originally Posted by JT Camaro

Interesting, I always read the manual as pulling 84154731 off for track use

I know, right. The majority of posts here state this. A lot of folks say they threw 84154731 away and run 84234055 on track and street. Nothing wrong with it, but perhaps a bit better performance can be gained from running only *4731 on the track.
I'm going to run them for my next track day......Probably drop 6-7 seconds off of my PB

[h018871]

I ordered 84244390 - (ZLE) DEFLECTOR,FRONT BUMPER FASCIA CENTER AIR
It is indeed taller, as an added benefit it fits the bottom of the spoiler better too. For proper installation you will need one #11516807, pop rivet.
TX does require a front plate. I use the Sto-n-Sho, holes have to be drilled for the mount, the picture is from their instructions.

It measures just under 1.5in (36mm) in the center, slightly less than 50% more than the ZL1 piece.

[RUQWIKR]

I guess I have lost some material, about 4-5mm off the height! Not too bad considering how long I've had the same one on and how much the car is tracked.

[h018871]

From the front it looks severely worn. It's hard to tell from the picture, but the rear edge still has the factory round edge. So not much wear actually. This is the ZL1 air dam

[Badmojo]

The 2018 Track Preparation manual appears to contradict the 2018 High Performance Supplement.

[Stephen12ZL1]

wow...how are we going to get an accurate answer to these confusing potentially contradicting documents? Is this an "ask Al" situation?