vtirocz

I'm looking to convert my '00 Z28 t-top car to a hardtop to increase the torsional rigidity of the chassis and have a couple questions:

1. Have any sponsors done this conversion and if so, what is the ballpark cost for this work?
2. How much would it cost for parts alone?
3. Do the hardtops on 4th gen f-bodys eliminate the dash 'creeks'?

I understand the hardtop only has two stamped pieces connecting the sail panel to the windshield, but I think this would significantly stiffen up the chassis and increase torsional rigidity.

Thanks,
Jim

BLKWS.6

Dont mess with it. Get subframes/X braces and call it a day.

EchoMirage

iTrader: (3)

subframes aren't a huge differance. talk to Sam Strano, his all out racecars don't have SFC. get them if you want, but it's not 'needed' to really beef up the car. Also, from what I've heard on here, hardtops have the same roof frame and bracing that t-tops do. Meaning the only real differance is sheetmetal. 4th gens aren't like 3rd or 2nd gens, where there was a big differance between t-top and hardtop rigidity. 4ths were designed to have t-tops, and are built accordingly.

vtirocz

Thanks for the responses. I do have BMR boxed SFCs and these seemed to stiffen up the chassis (although it is hard to quantify how much). However, when driving over railroad tracks or rough roads, the chassis does flex enough to get dash "creeks."

Also, the two stamped pieces connecting the sail panel to the windshield should be very rigid in compression/tension and would definitely increase the rigidity of the chassis. If you stick your finger in the t-top gap just driving down the highway, you will feel the chassis deflecting. The two stamped pieces will eliminate or significantly reduce this deflection. However, the rest of the chassis may flex enough to still have the dash creeks.

Anyone with both a hardtop and t-top car, could you please comment on the chassis rigidity between the two.

Thanks,
Jim

bww3588

iTrader: (49)

what the t-top car doesnt have that the hard top car has is the two braces above the windows on each door connecting the windshield to the sail panel. on the t-top cars these "braces" are part of the t-top itself so it flexes with the glass peice. thats the real strenght adder there. all you really would have to do is find a hard top car and cut the braces out of it and weld them in your car, remove the weather stripping and find a way to seal the outer skin to the inner shells. its the exact opposite of putting t-tops in a hardtop. i suggest you look up writeups on that, as to get a general idea of what needs to be done. plus, for all your parts you need to buy for this, you can make up the cost in selling your t-tops. i see them going from anywhere from 100-200 bucks a peice.

Ls1Bait

Seems like it would be alot of work, plus you couldnt enjoy the t-tops.

JD_AMG

His racers dont have them because the rules dont allow it, he himself said if they did allow it his car would have SFC's.
He often stresses though, to do SFC's later on, and go for things like shocks first.

JD_AMG

As for dash creeks, get a car that was not abused. I have 50,000 miles on my car and counting, 0 creeks or rattles.
Get some koni SA, they will probably eliminate the creeks by absorbing the bumps properly compared to the crappy stock shocks.

RevGTO

iTrader: (12)

Good advice on shocks, but our cars will often have squeaks and rattles even when they're not abused.

I've had both hardtop and t-top cars and don't notice much difference, except there will be some noise from the t-tops when it's really cold. The fixed roof panel is plastic or fiberglass and doesn't add any rigidity, although the fixed roof rails might.

Go through you interior and check for any loose pieces that can tighten down. Also, keep your tire pressures around the factory recommended 30lbs. Running 35 and up creates a lot of impact harshness.

chaman

iTrader: (5)

I dont think converting it to a t-top will give you a significant increase in torsional strentgh.

vtirocz

JD_AMG,
My '00 Z28 has 39k miles on it as was not abused. Under normal driving it has no squeeks/rattles/creeks... it's only when I go over rough roads or train tracks that I notice 'creeks'. The bending and torsional stiffness of these cars from the factory are not world class to say the least, so even a brand new one would do this.

RevGTO,
Thanks for your input. So the hardtop car does not feel noticeably stiffer than the t-top car?? Do you still have both?

chaman,
The hardtop will definitely have increased torsional rigidity over the t-top car, but I really can't quantify how much better it would be or if it would be worth doing this conversion.

Thanks,
Jim

JD_AMG

Are you absolutely positive its coming from the interior? These cars are known for going through suspension bushings, and when worn out/dry they will cause a creek/squeek noise. Lube up your sway bar bushings and see if that helps.
I dont see it helping very much. The hardtop cars are basically t-top cars without removable t-tops. They have the same bar running through the middle, connecting the windshield to the a-pillar, with just a plastic/fiberglass cover over it basically.

bww3588

iTrader: (49)

and 2 more FIXED peices connecting the A-pillar to the sail panel.

Benjamin Russick

iTrader: (1)

It would be less effort to put in a 4-point cage, which would be far more effective...

EchoMirage

iTrader: (3)

+1 for the cage, that will solve whatever problem you're after. Also, sometimes cars JUST make noise. F-bodies aren't caddys, built for ultra quiet, smooth rides. These are muscle cars. My 02 TA has not even 21k miles yet, and she makes a few squeaks here and there. Nothing major, and I don't notice anything when going over tracks. It's up for storage now, but when I do drive her in the cold, I do notice more squeaks, particularly from the t-top area. Sometimes cars just make noise, doesn't always mean they're lose or torsionally weak. If you want to really hear noise, go for a ride in my 78 TA. She makes more rattles then you'll ever hear, but it doesn't mean it'll fall apart with the next pothole.

Rhoop24

Here's what you need...
1. A for sale sign.
2. Keys to a hardtop car.

BLKWS.6

My 95 TA was hardtop, 170K highway miles, my 01 WS6 is T-top, 77K miles, babied. Both creak and squeek the same amount...VERY LITTLE!

jimoc

This is RevGTO posting on my brother's computer ... no, I don't have both cars currently ... Like BLKWS.6, I had a 94 Formula hardtop and now an 00 Formula w/t-tops. Each one had it's peculiar squeaks and rattles. But I wouldn't care if the t-top cars rattled more - I LOVE my t-tops off with the windows down on a nice sunny day. It would be worth it.

CJDZ24_Z28

iTrader: (75)

Waste of time. Look in my sig. I have a T-Top car and a hardtop car. My SS doesn't rattle or creek yet..but my hardtop with 119k has very few. Not worth it. You could prob go buy a Hardtop LT1 car for less than 3k now

PowerShift408

iTrader: (44)

+1 for a cage. No matter what, our cars squeak and rattle. You should drive mine with the spool out back. Maybe you should step up to a Vette?