Hi,

As my car is progressing, I am thinking about weight issues. A couple of
questions.

1. Can the sunroof be replace with a fiberglass top?
2. How much weight is saved by removing the window motors and such, but
leaving the glass?
3. Is is easy to remove HVAC while keeping the defroster working?
3. Are most people hitting the 2600 weight?

Thanks
Sid

1. No, you can "gut" it however

2. Alot, but you may want to "gut" the doors as well. Search for earlier threads on how to do this and what can be used as a replacement for towing/storage purposes.

3. I don't know the answer to this. I removed it completely. If i had to hazard a guess I would say not effectively.

4. I believe so. Look at pulling the windsheild wiper assemblies and headlight motor assemblies.

First a qestion . What year car do yo have and is it a 944 or 924S ?

Now about weight. The early (up to 86 in this case) 944's and the 924S's use a lighter tub in general these cars are easy to make weight. The 87/88 tubs have extra weight and are "hard" to make weight but with a 200# driver it can be done without going crazy.

How light can you get a 88 tub using the 944-spec rules. Ask Eric (Midwest series director) He did it for Nationals to run with GTS.

1. According to the rules (section 16.3.6), if you’re only replacing the sunroof, the replacement has to be metal. But, if you’re replacing the entire roof panel, it sounds like fiberglass might be ok as long as it’s fashioned to be similar in contour and weight to the roof of a stock non-sunroof car - or at least, that's the way that I read that rule, though it would seem to be a LOT of work to replace the entire roof panel.

2. No idea.

3. Yes, it’s possible to do this, but it takes some effort. On my car, we removed all of the AC components, and all of the ductwork that runs behind the dash, with the exception of the main duct that comes in through the firewall (we left the heater core and all other heater assemblies). We covered up all of the openings from the main duct assembly except for the top ones that blow straight at the windshield through the top of the dash, and set all of the operating controls that the HVAC console manages to what they would be set on if you wanted only the defroster to be on (full heat, defroster on, etc.) We then removed the HVAC console except for the fan switch (leaving the control wires that the HVAC console controls behind the dash), so that if I want to run the defroster (very handy in the rain or on a cold/soggy morning), I just turn the fan switch to the speed that I want, and I have an instant defroster. This can also come in handy for pulling some excess heat from the engine bay if it starts to overheat.

4. I think that most people are getting very close to the 2600 weight, but a late 944 needs to get a little more extreme with the gutting and weight reduction (the new rule provision for not needing to run the stock gauges helps with that, as you can now build a totally custom dash with all-aftermarket gauges and save a lot of weight over what the stock late model dash weighed.)

The roof has to be metal, but considerable weight can be saved here by putting in an aluminum panel.

The main wiring harness & fuse panel is over 30 lbs - can be replaced by a couple of pounds (at most) of wiring - Nick @ Bennington Motorsports has a custom harness for an early car available.

There's lots of motors, switches, and brackets that are not needed - spend some time looking under the car, and you'll find some weight.

A smaller battery helps as well.

You have to be pretty fussy to get to 2,600 lbs, but not ridiculously so. I got my '88 just under 2,400lbs dry. (2,570 with me in it). My new car will be lighter than that, but I'm adding in a big 4 liter fire supression system, and a big cool suit that will bering the wt. up, and maybe a passenger seat as well.


I found just a piece of ducting bent 90 degrees and zip-tied to the side-view mirror defrosted pretty well in a race situation, but if your stiff considering street use, it's different.

Post up some pics of how things are going!

Eric

Omn3d0n wrote:


1) No. The sunroof can be replaced with a metal panel. That is all. Stock sunroof planel is fiberglass.

2)Window motors are 15lbs for both. I have full doors with glass no motors. I operate the glass with pull straps.

3) I am sure there is a way. Defrost just pumps warm air up to the inside of the glass. The lightest sytem would be by keeping the heater core and fabbing a custom box. Early cars (83-85 and 924S)use a seperate hear box and AC box. You can ditch the AC box and leave the header box. I have my box still in with the flaps points up to defrost mode. My heater core is still in the box, but not connected. I even still have the fresh air blower too. This set-up worked well in my only fogging style rain race about 3 years ago.

4) I just ran over the scales at 2621lbs with driver at the end of my last race. I had 20lbs ballast and 1 gal or 2 of gas left over at the end of the race. In my car which is an 84 chassis I have alot of weight can still pull out. I figure at least 40-50lbs if needed to.