Rollcage question on doorbars ?

[Kruizer]

I see that when lads use fibreglass doors they install x-bars for protection but from looking at other RX8's built I've notice they take the below approach, is there any advantage to this ? Is it stronger or what is the motivation for this option ?

http://image.superstreetonline.com/f/31798494+w750+st0/sstp_1002_07_o+2009_mazda_rx_8_r3+cabin.jpg

Also is it necessary to brace the floor ?

http://image.superstreetonline.com/f/31798581+w750+st0/sstp_1002_63_o+2009_mazda_rx_8_r3+fire_extinguishe r.jpg
http://image.superstreetonline.com/f/31798584+w750+st0/sstp_1002_64_o+2009_mazda_rx_8_r3+cage.jpg


Some more pic's of the car :
http://image.superstreetonline.com/f/31798608+w750+st0/sstp_1002_81_o+2009_mazda_rx_8_r3+cage.jpg
http://image.superstreetonline.com/f/31798599+w750+st0/sstp_1002_72_o+2009_mazda_rx_8_r3+door_pop.jpg
http://image.superstreetonline.com/f/31798578+w750+st0/sstp_1002_62_o+2009_mazda_rx_8_r3+passenger_seat.j pg
http://image.superstreetonline.com/f/31798485+w750+st0/sstp_1002_04_o+2009_mazda_rx_8_r3+rear.jpg
http://image.superstreetonline.com/f/31798476+w750+st0/sstp_1002_01_o+2009_mazda_rx_8_r3+front.jpg

http://www.superstreetonline.com/featuredvehicles/sstp_1002_2009_mazda_rx_8_r3/photo_01.html

[Robbie Daly Ps13]

Side impact protection is basically why there like that...! x bar would do for drifting as speeds aren't as high as other sports...!

[Kruizer]

Thanks Robbie... But if you had the option this method would be better ? Looking at cages alot recently and I know myself once I get a proper cage in her it won't see road, only track :)

[DaveM-sport]

An x-bar can take up more room in the door opening on some cars. If you think how high each end of the x would be on the A-pilllar and main hoops so that the lowest point of the 'x' would still offer enough side impact protection, there would be very little room to get into the car especially on an RX8 where the door opening is so long in relation to its height.

Also from looking at the pics, the main hoop bends in fairly low down (only on my phone though so might b differnent on a bigger screen)

Floor reinforced due to an RX8 having no B-pillar of course.

[Kruizer]

I'm planning on putting the main hoop at the locking points of the rear door which essentially will be a false b pillar as such :) Well thats the plan anyways...

[DaveM-sport]

Arent the locking points ahead of the seat back though even in a road car with original seats?

Could be pretty awkward fitting the main hoop and diagonal bars as well as the seats in a good position if your tall :o

[Kruizer]

True lad, thankfully I'm a skinny git so I'll squeeze in :) I'm sure the lad doing it will be more than capable at designing up something cool.