How to lose weight in my 1st gen ITS RX7

Hi there,

i was the first time on the scale with my 1st gen ITS RX7 GSL-SE.
The result: 200 pounds overweight. After reading the GCR i don't see much potential to lose some more weight. Maybe you have some ideas.

The current status of the car:
- No interior left (but dash)
- No fan
- Race radiator
- Stock fuel tank
- Right door still stock
- Stock windows (no drivers door window)

The potenital i see is:
- Replace stock tank with fuel cell (how much would that bring? Even though i like the weight on the rear)

- Get rid of the interior of the passenger door. That probably would require a change of the cage. So i'm not sure about the value here.

Any comments?

Bars in the door (and removal of all the window stuff) is a good start.

Is your cage overbuilt?

I am not a big fan of using a cell to save weight over a stock tank, but there is much freedom in that area in IT.

What do you weigh?

Alot of extra weight is often "hidden" in wheels and tires. If your running a heavier tire (toyos come to mind) you may weigh 3-4 lbs/corner more than a hoosier. Ditto for wheels where alot of 15x7's are 5-6 lbs heavier than Volks and other optimal (but expensive) wheels. Weight savings by running the Hoosiers and expensive lightweight racing wheels can add-up to close to 40 lbs (all of which is unsprung). Of course if you already have these on you car there isn't any weight savings to be had here. As for doors, on our z i think we saved about ten lbs a door by adding nascar bars and gutting the inerds out. As for cells, many cars actually add weight over a stack tank if the cell is installed with the proper protection.

The last few lbs are always the most expensive ;)

Look at unsprung weight first. Wheels/tires are probably your biggest gains.

Hollow sway bar? How much do your shocks/springs weigh? Sunroof chassis? There's some extra bracing up there that can be swapped IF the SE's were available w/o sunroofs (guessing that they weren't)

There's some weight to be saved if you have power windows on the pass side. You're looking at 1.426-1.7 lbs per foot for tubing so you need to be able to save ~8 lbs for it to be worth adding a bar.

Fuel cell will probably end up adding weight... but in the rear where you might want it.

How heavy is the seat and bracketry?
Exhaust system?

How much weight can you, personally stand to loose?

I bet everyone of us, except MAYbe 10% of us can lose 20 pounds. And should. Some of us could lose more.

• Wheels and tires. 25 per corner would be a decent goal.
• Fasteners are free.
• Strip chassis of all undercoating, and trim.
• A cel can save weight in a 1st gen, but, you'll need to do a Jaz cell probably.
• Mufflers are often overweight. Mine weighs 6 pounds.
• Headers for rotaries are often really heavy. Stainless weighs less.
• Seats can be as little as 8 pounds.
• Gut that door!
• ditch all the gauges and put in a dash.
• Hollow sway bars.
• Remove exhaust shield and replace with lighter peices where needed.
• ALL emissions gear can go,
• Air box and filter should be as light as possible.
• Radiator should't be oversized, there's weight in the rad itself, plus the water.

WHen I gutted the door with electric window the net result was a 16# reduction. I weighted everything too.

Hoosiers are really lighter than Toyos? Are not Toyos a narrower tire?

Unfortunately, I am in that 90%. My wife says if I could lose 20# I'd be perfect. I tell her that fattery never hurts, but nobody likes a liar.

If this is who I think it is I used to own the car. Some of you may know it as it belonged to Dave Dean before me. One of the "Marguerita Motorsports" cars that ran at MO and Nelson Ledges. White GSL-SE with a blue #5.
Panasports with Hoosiers so not much to do there without spending a fortune to save a couple pounds.
I told him the same thing about the fuel cell, probably won't save.
The only suggestion I came up with was to gut the passenger door and add Nascar bars.
No gauges as all it has is a Stack dash.
He's in good shape but I suppose everyone could lose 5#'s.
Other than that, sell it and buy a 2nd Gen since you cut your teeth and are perhaps ready to move up!

200 pounds overweight, meaning 2550? That seems awfully heavy for a 1st gen. I assume the FI 13B is a little bit heavier than a carbed 12A, and I know the brakes are a little bigger, but I don't know of any ITA/7s that are anywhere near 2550 except with a really heavy driver. My IT7 car came in at the last race at 2375 with a cool suit (35lbs) and a fat-ass driver (275 lbs). If I weighed the official 180, I'd need ballast for the 2280 I'm allowed.

I've done most everything Jake and others have suggested and you should too. The only other factor I've seen is that it seems the 79-80 cars are a bit lighter than the later models, so you could probably save 50-75 pounds by switching tubs. Mine's a 79. But switching to a 2nd gen would undoubtedly make more sense.

wow, you're right Tom, ITS weight is 2350. I forgot about that. 2550 is heavy! I'm just under 2300 when I roll the scales. I personally need to lose 10 or so pounds, but at 6'3, it's a long road to 180. I haven't weighed that since freshman year in high school. My car is an 84, and I still have the sunroof, and a solid front sway bar. The new hollow bar is on the workbench, and the roof is getting surgery this week, so I should be close to minimum.

I think the 13Bs do carry a bit more weight in the engine area, and the brakes are slightly larger, but I can't imagine how it could be 200 over.

That engine seems to have a lot of scoot from what I saw at the IT-Fest at Mid Ohio last year. He wasn't getting passed on the straight, that's for sure. (Standard disclaimer: it was just one example, with unknown mods, driver, and corner exit speed, YMMV ;) )

Quote:

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Originally Posted by lateapex911

That engine seems to have a lot of scoot from what I saw at the IT-Fest at Mid Ohio last year. He wasn't getting passed on the straight, that's for sure. (Standard disclaimer: it was just one example, with unknown mods, driver, and corner exit speed, YMMV ;) )

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Nice disclaimer! lol :D:happy204::rolleyes:


Love those first gens! have one for a street car...

Wow! What an overwhelming response. Thanks to everyone for their input.

@ITS5GB: Yep, its me. And nope, won't sell it. I still need to find 1 solid second before that day comes :smilie_pokal:. I just thought i could accelerate this process by losing some weight.


Car is on Panasport wheels and Hoosiers so no potential there.
Fuell cell will obviously not bring it either.
Gutting my right door, ok, maybe 10 pounds.
The exhaust might also bring 10 is guess.
Radiator is big but needs to, cars getting borderline hot if i'm chasing a pack.
Stack dash is in.
And me and my belly is 230pounds.

So what i take with me from this discussion: Improve the driving.

Weight is supposed to be 2350?, so required tube is now 1.5x.095 correct? (been a while since I've caged anything "light" for SCCA) My guess is that the cage may be overbuilt with heavier tubing. .120 wall or maybe even 1.75x.120? That's a difficult place to loose weight w/o a lot of expense...

Do you run an Optima battery? If so ditch it for the stock battery....Optima's are heavy.

R

Quote:

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Originally Posted by Doc Bro

Do you run an Optima battery? If so ditch it for the stock battery....Optima's are heavy.

R

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Thats a great idea. Never would have thought of that!!!! I think I will use that one!

I have an Optima as well. With my 200# of raw muscle (I jest) I cross the scales at 2340. Do you think my battery is 60# heavier than a stock unit? ;)

Seriously, how much heavier are they? I'm not going to run out and replace a perfectly good battery, but the next one that dies in my wife's SUV might get replaced with a gently raced Optima and a lighter battery would go in the IT7.

Optima Red Top Group 35 battery RED35: Weight 31.7

Quote:

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Originally Posted by tom_sprecher

I have an Optima as well. With my 200# of raw muscle (I jest) I cross the scales at 2340. Do you think my battery is 60# heavier than a stock unit? ;)

Seriously, how much heavier are they? I'm not going to run out and replace a perfectly good battery, but the next one that dies in my wife's SUV might get replaced with a gently raced Optima and a lighter battery would go in the IT7.

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My POS Optima was 40#... I'd rather lose the weight with a battery than get on a treadmill....Let's face it 5# is 5#, replace the battery and you won't feel guilty about that 1 "extra" beer!!:happy204:

Revisit the wheels. What size are they? If they are 13x7, there are options out there in the 8-9# range. If they are 15x7, you are giving up a lot of tire weight with wheel weight. So there may be a little room here.

The cooling is often an issue of airflow management and proper ducting. This made a big difference on cars I have worked on, to the point that I have looked at using a smaller radiator in my car. Of course water and water wetter as a coolant (minimal antifreeze if you are in a place/time that requires it) will also maximize heat transfer. Maybe try some different water pump speeds and see how that impacts cooling.

There is some weight to be lost in pullys.

The hard part is the area with the most potential - you. I am blessed to be 180-190 despite a 6-4 frame, but have racer friends that work very hard on this one, especially the one that is trying to get his rabbit down into the 1500s with him in the seat.

The Optima came with the car, which at those prices ($150), that's the only way it would be there. It also weighs 41#. I'm having a hard time finding out what group was stock. Some sites say 21, some 25, some 34. Which is it?

It all adds up. Or down. I still can not fathom how that car is 2550! Something isn't right. From the description though, there's certainly some weight in the car that could be lost (50) ....

In the end, it becomes a money deal. And often the money is better spent developing the driver. Once the driver is not the dullest part, then it gets spendy to find the last bits.

My car has gotten to it's weight the classic way. Every time something needed to be done, weight was a strong consideration. My fuel tank was rusting, so, I could replace it with new, ($$$) or put a cel in. In the end, the cel cost nearly what the stock tank cost, but there were weight savings with the cel. And so on.

The car is a good strong car. When Dave owned it he ran 1:45's at MO. I ran it at Gingerman(1:39's) and Grattan(1:32's) in my Sophmore season('04) but mainly at Waterford Hills. ITS record at WHRRI was 1:16:604 and I had run the car as fast as 1:17:303 but normally in the 18's. Mat is still working on getting the car consistently in the 19's.
Mat, what you need to do is let me take it out to see if it still "has it"!:cool:

BTW, Robbie Huffmaster, who, with his dad Ray, used to be regulars at WHRRI before heading off to the pro ranks, recently returned and completely decimated the old ITS record. Robbies new record in the #27 former ARRC and IT Festival winning RX7.........1:15:067.
Unbeleivable. Just when you think your getting better..................and it's not like these cars/drivers are slouches. I'm running Chris Ludwigs old car, albeit not his motor, one of the cars is Kris Smith's former IT Festival winning RX7, and one of the drivers qualified 4th in the Pro-IT at The ARRC in '07 before being punted off and totalling that RX7, and 2 of the drivers finished 2nd(or 3rd, can't remember) in the ARRC Enduro last year so.....
I should post the picture of the following day grid as all of us gridded 2 through 6 put for sale signs on our cars that read "Humiliated by Rob Huffmaster, For Sale, cheap!"
Glad to have them back though, great guys.

Am i allowed to:

- Remove the actuators that operate the headlights?
- Remove the structural enforcement for the bonnet?

No. You are only allowed to do the things that are listed as allowed modifications. First line in the book (OK, fist page or so of the ITCS) says you can't do anything that's not mentioned. Therefor, anything else is illegal.

In other words, IIDSYCYC.
If It Doesn't Say You Can, You Can't