I want to replace my hatch with a CF hatch and lexan.

My car already has a Greddy TT setup up front which added about 80 lbs up there. More like 100 but I have a 3lb dry CF shock tower brace replacing the heavy stock one.

Would removing approx 75lbs from the rear going to upset the balance? I also have removed the spare, jack, carpet etc.

A 4 point cage in going in there next to add some weight to the rear and I will relocate the battery to the trunk.

Would all these changes end up being a negligeable affect on balance or detrimental?

 

Keep in mind the hatch is located quite high in relation to the rest of the car. Reducing weight there should reduce the Zs center of gravity with negligible effects on weight distribution.

Having said that, the changes you're making to your car won't do you any favors if you decide to compete in any organized class. Most likely will place you in unlimited classifications against cars with HUGE HP and changes...

 

Taking weight out is generally more important then balance, unless you're limited in some odd way by rules. Remember, cars with 65F and 35R weight distributions can be made to get around a race track very quickly.

 

I have huge HP and changes.... 670 HP isn't enough?!?!?!?!? We'll I'll have to turn the boost up then.

My car is so very far from OEM.

I agree on the lower CG, but I'm not convinced about the little effect on balance.

 

do it...

 

You do it..... then report back.

 

You caaannnnnn dooooooo IT!!!!!!

 

Unfortunately I have not seen the numbers from a Z with similar mods to yours in the front get corner balanced, and I have also not seen numbers from the same car with a CF hatch and lexan installed.

I can say, that I would certainly like to do it.

You'd have to think that it would change the weight distribution %, but not as much as you'd think. Compensate by running a slightly softer rear shock setting or maybe 1 lower PSI in the rear tires?

 

Just trying to be helpful. 670 Hp is plenty, but when you're running the super unlimited (NASA) or SPO (SCCA) classes, you'll find PLENTY of quick cars!

If you're that concerned about balance, the best way to find out is to locate a local shop with corner scales and the knowledge to use them. After getting baseline figures, roll the car off and remove the rear hatch. You can even add a few pounds in the rear to simulate the lightened hatch and record the new F/R balance.

 

I believe the lexan glass replacement, though it saves the most weight, will be the mod to put you into really rediculous competition categories. Not sure of the street legality, either, though convertibles run with plastic rear windows. Moving the battery won't make much difference, seeing as it is already close to the middle, on the passenger side to balance some of the weight of the driver. The roll cage should help balance things out though, as you mentioned.

 

Why not CF doors?

 

Unlimited isn't just about power but weight. Can you get your car down to 1200 lbs? How about 1000 lbs of down force?

It's a very expensive area to run, and going against Ultimas and Radicals can be frustrating. Just keep that in mind.

 

hey Jet are you planning on competing with your car or just continue
doing track days? i think a lot of the members are getting that
impression from what i am reading but i have not gotten that from our
previous discussions. I forgot to ask before, but is this car your daily
driver? mine is but i do not have half mods that you do.

 

I use my car on the street occasionally to take to car meets, and I don't want to put in a NASCAR style cage. But I was looking for a set of CF doors, and none of them are actually CF. They are FRP with a layer of CF venear. The lightest I found was a set of B-Magic doors which use FRP with a honeycomb sandwhich and a CF venear.

I certainly am not up to the level of a competition driver yet. But I would like to eventually compete on some level. What type of racing I will do is still up in the air. I have to do more research into what the next step would be after running HPDE.

My car is not a daily driver. It's just not a comfortable car to drive around anymore.

 

i have a 5 point rear roll over bar (weld in), cf hatch, but stock glass, pretty much the same setup as you Jet, but obviously not as powerful :P (but i probably have more carbon than you!)

i had the car corner balanced when i did my alignment. i didnt notice that much of a balance difference, the scales said i'm 53% front, 47% rear weight distributed, with me in the seat. car feels good.. during acceleration, probably would shift more to the rear, getting close to 50/50..

i would say lexan and cf hatch would be negligible for your z.

 

Do you remember what it weighed?

I'm just curious.

 

Hit up member "SpoilsofWar" he's turbo'd with a CF hatch and Lexan.

 

im getting re-corner balanced/aligned next week (hopefully) i'll post the specs up. i've added stuff since last time-

 

Thak you for the information!

 

Jet, a few things come to mind....

If you are going to go with big HP and run the super unlimited, you will need to lighten the car as best you can. CF doors, CF fenders, CF hood, CF trunk, lexan, drop the entire interior, etc.

If you are going to lighten the car up and run big HP, get a NASCAR style cage. You are entering an area with your car that can bite you with only a very little mistake. I have driven a Z such as yours and say this from the heart...don't skimp on the safety stuff with that kind of performance. You may not live to regret it. It's not the HP that kills you, it just can kill you faster. If you are lucky, you only end up

If I am reading correctly, you are an HPDE'r and have not actually raced yet. I REALLY suggest you think about starting with less HP before you crank it up to that level. Remember the saying "you have to slow down to go faster?" It applies to the learning curve, too.

Figure out what class you want to run before you dump a ton more money in the car. You may find you built a car that won't compete and has a very limited area to run in. I have seen a lot of people build a car that is just useless and then spend just as much making what they should have in the first place. One suggesting I have is endurance racing. It's more about car preservation and consistency. Don't get me wrong, you're still hauling ***, you'e just not at full tilt the whole time like a sprint race. I think they are great and every racer should try them. Some try them and don't go to sprints again.

lastly, you are entering the point of no return with the streetability of the car...even for weekends. With the mods you are doing and where you are going with it, you really should decide if you want to drive it on the street anymore. Oh, something to think about, CF parts are not designed for street use due to their make up and their ability to stand up in a crash. Again, think about your safety level and what the car is really being built for.

Just some things I think are important. GL with whatever you choose to do.