C5Natie

Hey there peeps. I've had my eye on some 3/8" tunnel plates for my C5. I've seen positive reviews about how much stiffer and solid the car supposedly feels but I haven't really seen any feedback from someone who tracks their car and could/would notice an actual improvement. Was wondering what your opinions would be on this and whether it makes a difference and is worth $250-280. Thanks.

Last C5

Noticed a big difference right of way. The cockpit was much cooler. Can't say I really noticed much difference in stiffness in the car, but the reduction in heat was worth the investment.

C5Natie

Thanks for the input. Sometimes I cant even keep my phone in the center console because it gives me a high temp warning lol

mountainbiker2

I had one. The inside is way cooler for sure. It will diffenently stiffen the car. You can feel the stiffnes without a doubt. Does it make your car go faster? When I use to go through the canyons at a good pace, it would bounce all over the place off the bumps.

Steve

Nowanker

I installed one one my base C5, immediately noticed reduction in cowl shake. On the freeway, I could feel a wave of vibration start at the F, roll through the car to the back, then start over at the F. It's still there, but diminished by about 80%.

aaronc7

I have my stock one off right now, in the middle of a clutch swap. Was going to try painting mine with high temp ceramic paint to see if it would do anything in the heat department...if not....oh well, only $10 wasted.

TRAKOUT

Get it! Insulate before install. Well worth the $$ and labor

janky

I installed an EE 1/4" version with ceramic coating about a year ago and noticed an immediate increase in body stiffness and cooler center tunnel temps. No downside other than a touch of added weight, but it is extremely low and centralized in the chassis.

troyguitar

I was told by the phoenix racing guys that they only use them as a good place to put ballast.

C5Natie

Thanks guys. I decided to pull the trigger on a 3/8" plate from Elite Engineering. Looking forward to the results.

Nowanker

Do their cars run a cage? That alone might increase stiffness enough to make the plate irrelevant. I don't have back to back lap times to cite, but the reduction in chassis shake on the street was impressive (Base C5). C5 Z06 is stiffer already with the hard top... but I'd do one in a heartbeat there too.

Supercharged111

What is this chassis/cowl shake of which you guys speak? I have a C5Z and may well have accepted this phenomenon as normal.

Nowanker

The whole car develops sort of a rythmic vibration that you can feel traveling through... Sort of like wheel imbalance, but vaguely different. Unibody convertibles show it the worst... if you drive an e30 BMW 3 series 'vert, you'll know exactly!
I can feel it on the freeway as a vibrating wave, starts at the front and rolls through to the back, immediately starts again at the front. Maybe a 2 to 3 second period? Maybe 90% diminished with the tunnel plate, from really noticeable to almost gone.

JakesBlackZ06

what do you mean it felt like it would bounce all over the place? as-in too stiff? or like rear end hop or something?

ive also thought on and off about a tunnel plate, just never really got good info on them besides vendors trying to get me to "buy theirs because its better then all the competitions" instead of just the facts. Come to think of it ive noticed more of that kind of stuff on here in the last year of so, but oh well sorry for the rant.

troyguitar

Yeah they are only running caged cars, that is another variable for sure.

VGLNTE1

How does adding a thicker plate reduce temp?

z06801

Mine has a ceramic coating, helps keep the heat from exhaust out.

Larry Myers

I installed the EE Engineering insulated tunnel plate.

Was unable to discern any improvement in heat reduction or increased chassis stiffness.

77vette05

I'm installing a 3/8 plate this winter. I have read a few post that the oem bolts for the factory plate will work but are a little short for the 3/8" plate.
Check out Hillman body bolts M6-1.00x25 from home depot. There about 5 threads longer than factory. They also have a 10mm head instead of the factory 8mm.

Guard Dad

I can't speak to the plates' effectiveness but as to vibration in general, if you have a targa just try driving around with the roof off and you will notice a bit more vibration and flex in the car in general and the cowl/dash area in particular. That is the sort of vibration everyone is talking about.