Hard top, soft top up or soft top down for motorsport?

Nuddy · Postby **Nuddy** » Fri Mar 03, 2017 10:11 pm

I have just located a hardtop for our NB8a
I am wondering what configuration to use for motorsport. Running class1 - standard.
If i use the hardtop the car will be heavier, can i remove the soft top to compensate for the weight of the hardtop?
If I can't remove the soft top I imagine the car will be faster without the hardtop.
Will it be faster with the top up or down?

MX593 · Postby **MX593** » Sat Mar 04, 2017 5:23 am

You'll have to leave the soft top in the car when you use the hardtop in class 1. It's not till you get into the race type classes that the soft top can be removed when running a hardtop. There's not that much in the top speed between hardtop and soft top. The aerodynamics may be a bit better with the hardtop and the car may be a bit stiffer. I sometimes run the hardtop and sometimes run the soft top and haven't noticed any appreciable difference.

MX593 · Postby **MX593** » Sat Mar 04, 2017 5:24 am

And Wakefield Park rules require the soft top to be up unless a full roll cage is fitted.

Guran · Postby **Guran** » Sat Mar 04, 2017 8:35 am

I faced this dilemma years ago with my NA6. MX593 is correct. You must leave the softtop in if you want to run in stock class. Using a stock hardtop just adds ~20kg with no significant benefit. I did try using a carbon fibre hardtop for a short while - the eligibility officer at supersprints gave the OK provided the softtop was still in. But it was a pain to remove, stank of resin, the window quickly went cloudy, and made no real difference to laptimes from any possible aero benefit. I just run with the softtop up which is quicker than with it down.

manga_blue · Postby **manga_blue** » Sat Mar 04, 2017 8:44 am

MX593 wrote:And Wakefield Park rules require the soft top to be up unless a full roll cage is fitted.

or unless you are to tall to fit under the soft top with a helmet on, in which case you must seek dispensation to run top down.

Nuddy · Postby **Nuddy** » Fri Oct 27, 2017 5:40 pm

manga_blue wrote:
MX593 wrote:And Wakefield Park rules require the soft top to be up unless a full roll cage is fitted.
or unless you are to tall to fit under the soft top with a helmet on, in which case you must seek dispensation to run top down.

OK different question now.
I bought Dan's NC and the NB is now sold.
My NC has a CAMS approved welded in half cage. It has no soft top. It has a carbo fibre hardtop which bolts on, not a 'clip-on".
I leave the top at home when I go for a country drive but so far for the track I run with the hardtop on.
I know I must keep it on at Wakefield but would like to run with it down elsewhere.
Is it only required at Wakefield?

hks_kansei · Postby **hks_kansei** » Fri Oct 27, 2017 6:08 pm

Never really.understood the "no bar, top up" rule.

It's not like a sheet of vinyl stretched over some 20mm tuning is going to do anything in a rollover other than snap off and impale you.

Nuddy · Postby **Nuddy** » Fri Oct 27, 2017 11:18 pm

Yes sometimes it is hard to make sense of some of the rules.
I have learned over many years and several sports that rule makers have something in mind that they want to achieve and they write a rule that they hope will achieve it. However instead of making it clear exactly what they want to achieve they devise a round about way which often does not achieve the desired result and carries unintended consequences.
So we blindly obey.

rascal · Postby **rascal** » Sat Oct 28, 2017 9:47 am

A slightly unrelated to rollbar part of the reason for the softtop up rule is so arms don't flail around and get crushed betwen car and outside ground/objects if the car rolls. Having a flimsy covering whilst offering no impact protection, does contain your limbs somewhat.
Similar reason why some tracks/organizers specify that windows must always be up (even on 30+ degree days) else you get black flagged.

Nuddy · Postby **Nuddy** » Sat Oct 28, 2017 6:40 pm

Yet if you have a full cage you can run without the soft top.

hks_kansei · Postby **hks_kansei** » Sat Oct 28, 2017 9:43 pm

rascal wrote:A slightly unrelated to rollbar part of the reason for the softtop up rule is so arms don't flail around and get crushed betwen car and outside ground/objects if the car rolls. Having a flimsy covering whilst offering no impact protection, does contain your limbs somewhat.
Similar reason why some tracks/organizers specify that windows must always be up (even on 30+ degree days) else you get black flagged.

I considered that, however it doesn't make sense since a rollbar won't contain limbs in a roll, if anything the bars just give you more crush points if your arms flail about.

But yeah, I can only assume it's just a weird general rule that makes sense on some classes not mx5 related.

wasp47 · Postby **wasp47** » Sun Oct 29, 2017 9:21 am

Hard tops, soft tops, roll cages, crash helmets, seat belts
Where are the real men in their silk shirts :lol:

ps the obvious answer is DEAD!

Nuddy · Postby **Nuddy** » Sun Oct 29, 2017 11:57 pm

Started in 72 with no roll bars etc. Didn't get my first cage in 77.
These days I want all the safety gear I can get. My 3rd roo without a bar or cage:

160075a.jpg

The American · Postby **The American** » Mon Oct 30, 2017 6:13 am

I changed my helmet and added a neck restraint before the last Hillclimb, and as a result my seating position has changed slightly, and my helmet now has little/no clearance below the roll bar.

The scrutineers told me I had to run with the soft top up in order to continue after the first run - that or be excluded from the event. I complied and sweated.

In truth, I agree with them (although not with the ‘see no evil’ solution) and am trying to work out how to get lower.