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-   -   Hardtop vs. sunroof FD for track (https://www.rx7club.com/race-car-tech-103/hardtop-vs-sunroof-fd-track-990807/)

sittinSideways 03-11-12 03:04 PM

Hardtop vs. sunroof FD for track
 
Hey, so first of all I did use the search function (I searched "titles only" with the keywords "slicktop," "hardtop," and "hard top.") However, I am still not 100% sure what the weight difference is between a slicktop FD and a FD with a sunroof. Also, is the difference in rigidity remarkable? Would someone primarily interested in road racing/auto X be better off with a slicktop or is the difference in rigidity/weight negligible?

I ask because I know there can sometimes be a big difference between slicktops and other types of roofs - for example, the 300ZX slicktop is 300lbs lighter than the t-top model and noticeably more rigid.

Thanks.

j9fd3s 03-11-12 04:17 PM

i've never heard the term slicktop..

anyways the weight difference is about 10lbs, its going to vary a teeny bit if its a glass roof, or a metal one.

structurally the FD is very solid, sunroof or not isn't a big deal. Mazda actually has an sae paper on the body shell.

rcracer_tx 03-11-12 06:31 PM

The difference is so negligible that it not worth making a decision based on it. I personally have an r1 which doesn't have a sunroof which is nice to have the extra head room if you are tall but if I could choose I would have preferred having the sunroof. I will be doing some track days after I re-do the suspension on the car and built the car with that in mind (a half bridge t0r will have a great track power-band). If you don't have A/C it is a big plus to have a sunroof as the car got really hot this last summer when it didn't have functioning air conditioning...

ptrhahn 03-11-12 06:41 PM

Structurally, there's no difference at all. The weight is somewhere around 15-20 lbs, but of course it's at the very top of the car. Unless you're 6'8", headroom won't likely be an issue once you've mounted race seats.

sittinSideways 03-11-12 07:25 PM

Excellent, thanks for the responses guys.

EDIT: found that SAE paper you were referring to: http://papers.sae.org/920244/
Anyone happen to have a copy or know where I could acquire it for free?

jkstill 03-12-12 05:37 PM


Originally Posted by ptrhahn (Post 11013329)
Structurally, there's no difference at all. The weight is somewhere around 15-20 lbs, but of course it's at the very top of the car. Unless you're 6'8", headroom won't likely be an issue once you've mounted race seats.

It is not just your height and seats, but the length or your trunk (yours, not the cars) - basically your height minus inseam.

I am 5' 10.5" tall.

My FD has Corbeau race seats on sliders. The back feet of the seats were removed for better clearance.

With my sunroof FD I will hit my head on the roof sometimes.

Going to non-adjustable seat mounts will provide more clearance.

The only reason I have sliding mounts is seat adjustability for co-drivers.

HadaVette 03-18-12 06:02 PM

I would have chosen a non-sunroof if I knew then what I know now... Bot only because of the extra headroom. I'm 5-11, and a helmet with stock seats does not fit very well - I have to recline the seat a lot.

Travis R 03-19-12 04:01 PM

I've only driven 1 FD, but it had a sunroof, and I had a helmet on, and it was very annoying how far back I had to recline the seat. I'm 6'2"
So if I was looking for a track FD...

RockLobster 03-20-12 03:54 PM

6'4" tall and i dont fit in any FD with a helmet on period. Oddly enough it is one of the reasons I own FCs...

But there is about a 1.5" difference in headroom between sunroof cars and non-sunroof cars in stock form...both FC and FD.

ptrhahn 03-20-12 09:07 PM

You guys need fixed mount race seats, where the butt of the seat is hitting the floor.

RotaryRX-007 03-20-12 10:06 PM

+1 for ass of seat on the floor pan.

Non sunroof is the preferred for track duty for the prior reasons listed. But on the other hand, sunroof cars tend to be a little cheaper to buy. There's carbon replacement panels (i think one of the vendors offer it) for the sunroof and you can just gut the assembly to shave the weight. Since the rigidity between the two is kinda negligible, whichever car you get the best deal on, go for it.

RockLobster 03-21-12 09:54 AM

Makes no difference in my case. Too big for FDs...

Although a buddy of mine is an inch taller and he makes it work because he is all legs...

PandazRx-7 03-21-12 06:05 PM


Originally Posted by RotaryRX-007 (Post 11024640)
+1 for ass of seat on the floor pan.

Non sunroof is the preferred for track duty for the prior reasons listed. But on the other hand, sunroof cars tend to be a little cheaper to buy. There's carbon replacement panels (i think one of the vendors offer it) for the sunroof and you can just gut the assembly to shave the weight. Since the rigidity between the two is kinda negligible, whichever car you get the best deal on, go for it.


That's what I did...building a new track car with sunroof removed (probably 20lbs+) and plugged it a carbon fiber plug which weighed in at a hair over 3lbs. Cage hugs the roof so tight that there is no way to remove the nuts for the panel now. Also had the lowest possible fixed mount seat rails made so I should be good to go with head room. I'm about 5'11".

initial_r90 04-13-12 04:27 PM

good info I'm 5'10 but have a large torso I'm gonna have to check this with a helmet before I buy a car

FD3S4Life 04-23-12 10:44 PM


Originally Posted by PandazRx-7 (Post 11025668)
That's what I did...building a new track car with sunroof removed (probably 20lbs+) and plugged it a carbon fiber plug which weighed in at a hair over 3lbs. Cage hugs the roof so tight that there is no way to remove the nuts for the panel now. Also had the lowest possible fixed mount seat rails made so I should be good to go with head room. I'm about 5'11".

Which vendor? im looking for a carbon sunroof plug right now too.


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