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-   -   Adding lightness lll (https://www.rx7club.com/race-car-tech-103/adding-lightness-lll-438477/)

jgrewe Jun 28, 2005 06:05 PM

Adding lightness lll
 
In my quest for weight reduction here is the latest on the FC Eprod car.
The tilt steering column weighs 10 lbs all stripped of plastic, ig. switch and wires.
The non tilt weighs 6 lbs. I could save another couple pounds but I like the colapsing column.

CrackHeadMel Jun 28, 2005 08:26 PM

what are you asking?

jgrewe Jun 28, 2005 10:35 PM

Nothing, just contributing to the collective knowledge. Somebody somewhere might be wondering how to take weight out of their car. As I've built my car I've been weighing stuff as it gets removed or changed. Soon I'll be posting pictures now that it's starting to look like a car again.

SPiN Racing Jun 29, 2005 12:16 AM

The funny part John..... I have 2 Tilt racks I am saving for my EP.
Granted.. I may end up just doing a coleman shaft and heim joint on the cage... with the borg(?) joints.. BUT... when it comes down to it in the end.. Cash may dictate I use the tilt column.

jgrewe Jun 29, 2005 09:52 AM

Yep, I was thinking a similar thing until I looked at the $250 price tag at Speedway Motors for a colapsable column(rules say we have to have one). I just made new mounts that moved the column over about 3" and back 2" then extended the section between the rack and column. Just go to u-pull-it and grab a non-tilt. No wait, you'll be racing against me, keep the heavy tilt column :D

tims Jun 29, 2005 05:50 PM

using a u-joint at the base of the column will ensure the column collapses under impact. The Sweet, Coleman, and Woodward columns are nice but not required to meet the rule. A simple modification of the stock setup, while removing the entire stock column, can yeild a very light and collapsable steering setup.

TrentO Jun 29, 2005 05:52 PM

Another option is to remove all the tilt hardware and just weld the tilt sections together. You cut off most of the bulk with a cut off wheel. I'd have to say all stripped down and gutted it probably isn't much heavier than the non-tilt columns

-Trent

jgrewe Jun 29, 2005 07:59 PM

I think the fact that there are 2 u-joints in the stock system qualifies it as colapsable for SCCA. So just putting a straight piece of DOM or steel rod in there in place of the stock column might be OK. If you only have a tilt column I would remove everything from the u-joint for the tilt back toward the driver and weld a shaft on the column to make it as long as you need. Then again, its only worth a few pounds so unless you've done everything else to lighten the car(as I have), there are many easier ways to shave weight. Heck I think you could save the same amount of weight by changing the stock steering wheel to an aluminum racing wheel!

tims Jun 30, 2005 05:25 PM

you can also remove the sheet metal "horn" that holds the column assembly. there is alot of unneeded material up high and the straight shaft leave alot of extra room on the drivers side. this is not a hard or expensive modification and is easy to do when the cage is being built. I also frees up room for the pedal assembly if converting to a twin master manual brake system. I would also cut out some of the sheet metal under the window frame right under the original fresh air vent to give even more access to the area under the windshield. this helps access the pedal assembly when the windshield is installed(wish I had done this on my car).

88IntegraLS Jul 1, 2005 01:00 AM

Strut tower cables instead of bars. Considering the struts bars get loaded in tension under hard cornering. Could be worth a pound or two.

scotty305 Jul 1, 2005 03:51 AM

88IntegraLS, that's a fascinating idea. How did you determine that they're seeing tension? I had always assumed the opposite.

-s-

EProdRx7 Jul 1, 2005 06:19 AM

Jeez guys stop thinking so much and just get the car on the track. Chances are that you will be under weight anyway. BTW I made the one in my car and there are no specs as to what constitutes a "calapsable" unit. So if it takes 1 or 1000 lbs of force to colapse who cares. Point is get the car on the track as soon as you can. There will be plenty of thins to fix and remake once you get it going. I hope you understand my point of view...

Travis R Jul 1, 2005 07:26 AM

...git 'er done?
;)

JEC-31 Jul 1, 2005 09:26 PM


Originally Posted by 88IntegraLS
Strut tower cables instead of bars. Considering the struts bars get loaded in tension under hard cornering. Could be worth a pound or two.


Good point for innovation, but I feel that it may be worth the grams to retain bars and their resistance to not only tension loads, but compression, up-down, and fore-aft movements also.

Stiffness in a car is much more valuable if it resists forces in lots of directions and not just one.

Drive a floppy car hard over an undulating track (cough backroad cough) and you'll feel it moving all over the place.

88IntegraLS Jul 3, 2005 12:47 AM

I'll have to try it one day when I'm bored. I'm pretty satisfied with my FC chassis as is, although what I think it really needs is a belly pan to bridge the transmission and exhaust tunnel, which would give a little drag reduction too. The twist strain on the chassis in cornering is what I think would cause problems with understeer / oversteer / transitions.

SPiN Racing Jul 3, 2005 05:00 AM


Originally Posted by EProdRx7
get the car on the track. .

Woot

(bit drunk after a 9+ hour party at the house.. and done having sex etc.. but the rooms spinning too much to lay down)

YEP... You are right.
And thats why I am racing the SHIT out of the ITA car.. and looking for a 5th wheel 40-50 foot trailer.... like the one you took to Sebring.. so I can get the EP car done and bring em BOTH to the track.

Sooo John.... If I get the EP car done.. you gonna fly/drive down and help run laps and make sure its set up right??

I do owe you for the Sebring and RA stuff.

EProdRx7 Jul 4, 2005 05:59 AM

Scott,
Sounds good to me. I'll even bring the rest of the parts I owe you!
JW


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