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How do I put my ISF on a diet?

6942 Views 14 Replies 6 Participants Last post by  Gymkata
Hey All,

I have just started looking into products to lighten up the ISF a bit. I don't want to break the bank, and for me its more about performance than aesthetics (i.e. I don't think a carbon fiber hood would really drop much weight).

I would appreciate it if anybody who has reduced the weight of their ISF would post what they have done so far. If anybody has weighed various ISF parts to see where weight could be shaved, please post this also.

So far, after cursory inspection and thought, I think there are two easy ways to drop weight. One would be replacing the battery with a lithium iron phosphate battery such as is sold on voltphreaks.com. I don't know how much the ISF battery weighs, but I am guessing between 45 and 50 lbs. The comperable lithium iron phosphate battery is about 5-7 lbs. These batteries are REALLY expensive though.

The other easy way to drop weight where is counts could be replacing the roof with a carbon fiber roof. I certainly wouldn't miss the sun roof, and I am guessing there would be a pretty hefty weight reduction.

Like I said, just wanted to voice what I had been thinking about and ask for anybody and everybody's input on the subject. Thanks in advance!
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CF mods are really the only way to go. I wouldn't suggest ripping out seats and such. You drive a luxury automobile, if you want a hot rod then go pick up a plastic Vette. :p

The IS-F has a beastly engine, if you want to go faster, upgrade the engine. :)
CF mods are really the only way to go. I wouldn't suggest ripping out seats and such. You drive a luxury automobile, if you want a hot rod then go pick up a plastic Vette. :p

The IS-F has a beastly engine, if you want to go faster, upgrade the engine. :)
Does anybody have any figures on what CF body pieces are available for the F and how much weight can actually be saved?

Phlabrasca, I wouldn't dream of ripping the seats out. I was just looking for heavy stock pieces (with little visibility) in the car, especially the engine bay, that could be replaced with lighter ones.

I am still hoping that someone out there has some suggestions other than taking out the spare tire. I know someone out there was planning on some serious weight reduction...I just can't remember who it was, or what thread it was in. They said they were aiming for 35XX pounds.
Does anybody have any figures on what CF body pieces are available for the F and how much weight can actually be saved?

Phlabrasca, I wouldn't dream of ripping the seats out. I was just looking for heavy stock pieces (with little visibility) in the car, especially the engine bay, that could be replaced with lighter ones.

I am still hoping that someone out there has some suggestions other than taking out the spare tire. I know someone out there was planning on some serious weight reduction...I just can't remember who it was, or what thread it was in. They said they were aiming for 35XX pounds.
http://www.superhonda.com/tech/weight_loss_guide.html

That gives you a good idea on weight reduction.
Thanks...interesting and helpful page.
carbon body parts would add up in a hurry. removing the spare tire and equipment drops 50lbs..... you could remove all the sound deadening from tire wells and whatnot for another 25lb loss like import tuner did i think? a significant performance gain could be had from getting lighter wheels and tires. the actual loss in lb would by magnified by the loss in rotational inertia and unsprung mass. improving accel, decel, turning, ride quality. you could swap out the front seats for light weight racing seats...perhaps bride or recaro. definately lighter then the 10 way power stock seats..... removing all the under hood panels will shave probably 4lbs lol....joez exhaust is lighter then the stock setup. other then that right now i dont have many ideas....
carbon body parts would add up in a hurry. removing the spare tire and equipment drops 50lbs..... you could remove all the sound deadening from tire wells and whatnot for another 25lb loss like import tuner did i think? a significant performance gain could be had from getting lighter wheels and tires. the actual loss in lb would by magnified by the loss in rotational inertia and unsprung mass. improving accel, decel, turning, ride quality. you could swap out the front seats for light weight racing seats...perhaps bride or recaro. definately lighter then the 10 way power stock seats..... removing all the under hood panels will shave probably 4lbs lol....joez exhaust is lighter then the stock setup. other then that right now i dont have many ideas....
Thanks doublexl. Yes, CF can get expensive. That is why I was wondering what other ideas people had. I like the idea of weight reduction because it mildlly improves every area of the car's performance...acceleration, handling, braking, etc.

I had thought about some lighter wheels. I think in the end they would probably be as heavy as stock considering I would go as wide as possible. I think I will wait at least another year until I do that though...was considering the HRE setup running 255 fronts and 295 rears. I know it would be expensive though.

I wish JoeZ would make a full Ti version of his exhaust. That would definitely drop weight. I would buy it. So far it is the best sounding system I have seen for the F...with a real clean setup too.
i plan on an HRE setup as well. you might end up saving weight. if you went with the carbon rims you would definateyl save weight. i really like the monobloks. funny that you also say 255 front 295 rear....cuz thats my plans...thats as big as you can go. 19x9 front 19x10.5 rear.
Yep...you gotta go as wide as possible with a relatively heavy car and decent power. The ISF slips and slides too much with the thin 225s and 255s. My S2000 has 225s and 255s, but is 1000 lbs lighter. I LOVE how glued to the road it is.
They make CF hood, front fenders and trunk as far as I know. I saw them at SEMA and they looked pretty good. I think the hood would save a considerable amount of weight, but as always...it's your money and the choice is yours. Losing the spare and new rims are both good choices as stated above. Plus with rims you get a fresh look and more grip if you go wider and get sticky tires.
If you're considering to change wheels, check out the WEDS wheels. They weigh about 17 to 19 pounds, compared to our stock which is about 24 or 26.
If you're considering to change wheels, check out the WEDS wheels. They weigh about 17 to 19 pounds, compared to our stock which is about 24 or 26.
Some of the WEDS look really good!

I thought I remember reading in one of the threads that there were minor rubbing issues running stock tires. I would want to go much wider. Do you know if the WEDS can be purchased in the correct offset to run a minimum of 245s front and 285s rear, but preferably 255s and 295s as HRE claims is possible with no rubbing. I have purchased too many wheel/tire packages in the past that did not fit properly.

I am probably not going to buy new wheels/tires until the stock ones need changing (hopefully a year). At that point, hopefully there will many more options for the ISF and more information about exact wheel widths/offsets to fit the widest tire possible.
http://www.lexusfforum.com/forums/showthread.php?t=1971&highlight=weds&page=3

Here's the thread you were talking about. Check post #24. There's a contact information you could use to verify your question.
I would be surprised if the carbon hood is much lighter than the aluminum stock one. I think most of the seibon products are pretty crappy and actually add weight. Last year when I actually felt the one on the 0-60 ISF, it was really flappy. I would always be concerned with it as speed. Light wheels and the light exhaust make a big difference. The Sunroof I would expect to be next most significant and easily targeted.

Carbon back seats for the front.

....not much else that is an easy target.
I would be surprised if the carbon hood is much lighter than the aluminum stock one. I think most of the seibon products are pretty crappy and actually add weight. Last year when I actually felt the one on the 0-60 ISF, it was really flappy. I would always be concerned with it as speed. Light wheels and the light exhaust make a big difference. The Sunroof I would expect to be next most significant and easily targeted.

Carbon back seats for the front.

....not much else that is an easy target.
I was thinking the same thing regarding a CF hood. I was also thinking that the roof would be the most beneficial place to drop weight when considering body roll reduction.
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