2017 STU Discussion!
Maybe I've just got lucky but as mentioned my Shorai has been kickass. If I had to replace it once a year or it exploded that would be a different story but in my experience it's been pretty much perfect.
If you've had bad experiences with mini batteries then I can understand the mindset of putting it in the trunk and being done with it. Also, if your car is already close to min weight then I also see it. But for me having an SSL being able to knock off 33# with a simple battery swap is a no brainer.
My goal is to get my car <3000# so I've got another 170# to go, lol!
If you've had bad experiences with mini batteries then I can understand the mindset of putting it in the trunk and being done with it. Also, if your car is already close to min weight then I also see it. But for me having an SSL being able to knock off 33# with a simple battery swap is a no brainer.
My goal is to get my car <3000# so I've got another 170# to go, lol!
I'm pretty sure I could get my evo in the 27xx range within SM rules but a big portion of that comes from the rear so I figure why bother. Accel and Braking aren't an issue for us but weight distribution totally sucks. So we stick with our 29xx weight and full rear interior since 2910 is my min weight.
So in my case it completely makes sense to do a big battery in the rear to forget about it. But in STU without any weight min and restrictions on other things that can be done, I would probably stick to lightweight lithium up front for a non-daily driver.
So in my case it completely makes sense to do a big battery in the rear to forget about it. But in STU without any weight min and restrictions on other things that can be done, I would probably stick to lightweight lithium up front for a non-daily driver.
You suck I wish my car was that light? To your point the biggest challenge we have is dropping the weight off the front and while that is preferred at the end of the day Im still in the mindset that less weight no matter where it comes from is better.
What were the big things you did to get your car so light? I've been all over the official weight reduction thread and while I know the 5# here 10# there stuff adds up over time it seems I need to either hack up my car or start getting really trick with expensive parts CF roof things like that. Im considering swapping on an AL roof to my car or CF granted the AL seems to be about half the cost of the CF and is something like 7# heaver than the CF but still something like 38# lighter than my steel roof.
What were the big things you did to get your car so light? I've been all over the official weight reduction thread and while I know the 5# here 10# there stuff adds up over time it seems I need to either hack up my car or start getting really trick with expensive parts CF roof things like that. Im considering swapping on an AL roof to my car or CF granted the AL seems to be about half the cost of the CF and is something like 7# heaver than the CF but still something like 38# lighter than my steel roof.
no I agree - if relocating the battery to the trunk were the easy button, I would do it. otherwise, can't hurt to cut 30lbs from the top upper left of the car.
I meant the alternator as far as it overcharging the battery/being too strong. That was one of the cited concerns from Shorai (posted above) as far as running a small battery. The 8/9 alternator, per LGTD, falls under appropriate spec for even a small battery - perhaps it is weaker/slower charging.
I meant the alternator as far as it overcharging the battery/being too strong. That was one of the cited concerns from Shorai (posted above) as far as running a small battery. The 8/9 alternator, per LGTD, falls under appropriate spec for even a small battery - perhaps it is weaker/slower charging.
Maybe I've just got lucky but as mentioned my Shorai has been kickass. If I had to replace it once a year or it exploded that would be a different story but in my experience it's been pretty much perfect.
If you've had bad experiences with mini batteries then I can understand the mindset of putting it in the trunk and being done with it. Also, if your car is already close to min weight then I also see it. But for me having an SSL being able to knock off 33# with a simple battery swap is a no brainer.
My goal is to get my car <3000# so I've got another 170# to go, lol!
If you've had bad experiences with mini batteries then I can understand the mindset of putting it in the trunk and being done with it. Also, if your car is already close to min weight then I also see it. But for me having an SSL being able to knock off 33# with a simple battery swap is a no brainer.
My goal is to get my car <3000# so I've got another 170# to go, lol!
I would like my car to be under 3,400 lbs LOL
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I also believe that lighter is better no matter where it came from and if that is in the trunk on our already light rear end, so be it. Too many benefits to ignore...
Not sure if you care about SCCA classing, but carbon roof is illegal till XP and alum roof is fine in STU (package conversion to SE would be easy since its not much).
The big stuff on my list are pretty much what everyone has already done, Exhaust, coilovers, battery, rear seats, etc. There are some harder to do big things like sound deadening (25lb for dash pad and floor pads), All radio crap (12lbs), Light rotors (5lbs for light, 15lbs for ultra light), AC (35lbs), Billet uprights/control arms (~12lbs, more if going from big bar back to stock), ACD relocation (16lbs off front, ~10lbs on rear), race seats (~5-10lbs each if you stick with stock belts).
Then are other things like a proper carbon hood (10lbs), carbon trunk (17lbs), wingless (7lbs), rear diff mounts (18lbs), carbon driveshaft (15lbs), and a whole host of ~5 things (Airbags, rear wiper motor, washer pump/res, motor mounts, intake mani brackets, evap can, trunk trim, BR crossmember bar...
Just depends how crazy you want to get
The big stuff on my list are pretty much what everyone has already done, Exhaust, coilovers, battery, rear seats, etc. There are some harder to do big things like sound deadening (25lb for dash pad and floor pads), All radio crap (12lbs), Light rotors (5lbs for light, 15lbs for ultra light), AC (35lbs), Billet uprights/control arms (~12lbs, more if going from big bar back to stock), ACD relocation (16lbs off front, ~10lbs on rear), race seats (~5-10lbs each if you stick with stock belts).
Then are other things like a proper carbon hood (10lbs), carbon trunk (17lbs), wingless (7lbs), rear diff mounts (18lbs), carbon driveshaft (15lbs), and a whole host of ~5 things (Airbags, rear wiper motor, washer pump/res, motor mounts, intake mani brackets, evap can, trunk trim, BR crossmember bar...
Just depends how crazy you want to get
Yeah I mean I dont really care about SCCA classing if Im being honest. I just play around locally with much more relaxed classing. While i would like to take a trip out to Lincoln at some point its by no means something that I really take into account and build my car around. For example I have a JDM rear on the car and a chromoly rear bumper beam which Im pretty sure already bumps me into XP, unless things have changed. So for me I modify my car in a means that I feel will be me the most bang for the buck so to speak.
My car hasnt been on scaled in a few years but it was 3205 when it was. Since then the only weight changes were I put in my 5# battery -33# installed a BR harness bar with harnesses +~13# I wanna say, relocated ACD to trunk and shaved probably around 5# off the bracket and just last weekend I put on a 2 piece Englewood driveshaft which shed another 13#.
So that puts me to around 3167 well call it 3170 for good measure.
There is a lot of low hanging fruit that I just havent gotten around to doing such as sound deadening and once I finally buy my truck Ill get rid of AC rear seats look into lighter front seats, probably go to an AL exhaust to drop another 20#.
But all in all I still have a ways to go. I think the SSL is something like 150# heavier than an SE although I cant seem to find that Vorshlag article at the moment where they weighed a few different models.
My car hasnt been on scaled in a few years but it was 3205 when it was. Since then the only weight changes were I put in my 5# battery -33# installed a BR harness bar with harnesses +~13# I wanna say, relocated ACD to trunk and shaved probably around 5# off the bracket and just last weekend I put on a 2 piece Englewood driveshaft which shed another 13#.
So that puts me to around 3167 well call it 3170 for good measure.
There is a lot of low hanging fruit that I just havent gotten around to doing such as sound deadening and once I finally buy my truck Ill get rid of AC rear seats look into lighter front seats, probably go to an AL exhaust to drop another 20#.
But all in all I still have a ways to go. I think the SSL is something like 150# heavier than an SE although I cant seem to find that Vorshlag article at the moment where they weighed a few different models.
I've been using a Deka ETX20L AGM battery. It's not Li-Ion light, but it's light enough and I don't have to worry about Li-Ion hassles and risks. My first one lasted through 4 winters of active use. It even outlasted the full-size Duralast I put in my wife's car at the same time.
The ETX20L is a bit bigger than the tiniest Deka that everyone uses, but I think the few extra pounds are a good tradeoff for the much higher reserve capacity. But the best part is that it's the same length as the stock battery width, so you can just lie it down in the stock battery tray. I re-use the stock battery hold down bracket with some shorter J-hooks I bought from McMaster. I can switch back to a full-size battery whenever I want by swapping the J-hooks.
I've thought about putting some high-current quick disconnects on the battery terminals so I can swap in a ~2lb battery for competition, but that's a lot of work for 10lbs weight savings.
The ETX20L is a bit bigger than the tiniest Deka that everyone uses, but I think the few extra pounds are a good tradeoff for the much higher reserve capacity. But the best part is that it's the same length as the stock battery width, so you can just lie it down in the stock battery tray. I re-use the stock battery hold down bracket with some shorter J-hooks I bought from McMaster. I can switch back to a full-size battery whenever I want by swapping the J-hooks.
I've thought about putting some high-current quick disconnects on the battery terminals so I can swap in a ~2lb battery for competition, but that's a lot of work for 10lbs weight savings.
Last edited by Construct; May 13, 2017 at 07:07 AM.
I've been using a Deka ETX14L AGM battery. It's not Li-Ion light, but it's light enough and I don't have to worry about Li-Ion hassles and risks. My first one lasted through 4 winters of active use. It even outlasted the full-size Duralast I put in my wife's car at the same time.
The ETX14L is a bit bigger than the tiniest Deka that everyone uses, but I think the few extra pounds are a good tradeoff for the much higher reserve capacity. But the best part is that it's the same length as the stock battery width, so you can just lie it down in the stock battery tray. I re-use the stock battery hold down bracket with some shorter J-hooks I bought from McMaster. I can switch back to a full-size battery whenever I want by swapping the J-hooks.
I've thought about putting some high-current quick disconnects on the battery terminals so I can swap in a ~2lb battery for competition, but that's a lot of work for 10lbs weight savings.
The ETX14L is a bit bigger than the tiniest Deka that everyone uses, but I think the few extra pounds are a good tradeoff for the much higher reserve capacity. But the best part is that it's the same length as the stock battery width, so you can just lie it down in the stock battery tray. I re-use the stock battery hold down bracket with some shorter J-hooks I bought from McMaster. I can switch back to a full-size battery whenever I want by swapping the J-hooks.
I've thought about putting some high-current quick disconnects on the battery terminals so I can swap in a ~2lb battery for competition, but that's a lot of work for 10lbs weight savings.
FWIW the shorai batteries are lithium-iron, but i don't know anything about anything to know what difference that makes for risks/trade offs. sorry to totally jack this into a lightweight battery discussion!
That theory is increasingly flawed as the portion of your lap times that are dependent on cornering performance increases. More front heavy (%) makes more push and you are limited in your ability to correct the balance by the fact that the inside rear will lift off the ground at a lower and lower threshold as your weight distribution shifts forward. Of course you can throw some 225's in the back to get it to balance out but then you absolutely destroy the forward accel capability.
So I get that, and by no means am I trying to argue with you as I have no leg to stand on if Im being honest so this is merely speculation. But what would you do in my situation being that I want to drop weight?
From a power perspective, Id say my car is fine in thats its not holding me back. Suspension is pretty decent at this point too. Seems like the biggest difference from my car and a true SM prepped evo is the weight and no r-comps which is an easy swap. Well, and of course the driver can always use some work.
But basically in my position what would you recommend? There are many avenues to explore when it comes to dropping the weight and I've been working on compiling a spreadsheet so I can go about this in a methodical manor. And not that I wouldnt much prefer to shed weight off the nose, things like rear seats and belts is a solid ~40# difference simple removal and not a permanent mod so seems very appealing. From the sounds of what you just said removing them would be doing myself a disservice. Same thing with BR chromoly mustache bar. I think its around 13# and a simple swap gratned that one cost money but still easy swap relatively inexpensive but in a terrible place. So do I not bother? And if I keep skipping out on these things then how the eff do I get my car sub 3000#?
And please don't think Im arguing with you as I am not. I value your opinion so am more than open to what you have to say...
From a power perspective, Id say my car is fine in thats its not holding me back. Suspension is pretty decent at this point too. Seems like the biggest difference from my car and a true SM prepped evo is the weight and no r-comps which is an easy swap. Well, and of course the driver can always use some work.
But basically in my position what would you recommend? There are many avenues to explore when it comes to dropping the weight and I've been working on compiling a spreadsheet so I can go about this in a methodical manor. And not that I wouldnt much prefer to shed weight off the nose, things like rear seats and belts is a solid ~40# difference simple removal and not a permanent mod so seems very appealing. From the sounds of what you just said removing them would be doing myself a disservice. Same thing with BR chromoly mustache bar. I think its around 13# and a simple swap gratned that one cost money but still easy swap relatively inexpensive but in a terrible place. So do I not bother? And if I keep skipping out on these things then how the eff do I get my car sub 3000#?
And please don't think Im arguing with you as I am not. I value your opinion so am more than open to what you have to say...
Marshal and I typically agree on this point, If weight comes out of the rear easily sure take it out. But don't spend money to remove it from there. And if something happens to add weight overall but reduce front weight, then do it.
Also, remove weight up high and beyond the wheels. So something like your roof swap is a great place to start but diff brackets (spending money, way down low, inline with the axle) is not.
Also, remove weight up high and beyond the wheels. So something like your roof swap is a great place to start but diff brackets (spending money, way down low, inline with the axle) is not.
OK we're in agreement then and that is exactly what I've been working to come up with a solid plan of attack within my spreadsheet. There is the first portion where its weight savings per $ spent which sorted gives me a good starting point of bang for the buck. However what Im struggling factoring in and weighing, no pun intended is how to take into account where the part resides on the car rotational mass, reversible and other compromises given the switch.
The roof seems to be good bang for the buck although cost of entry is a lil higher and the necessary work to get the job done is a lil more involved.
I just did the driveshaft, arguably rotational mass granted some comes from dropping one mount and the AL shaft does have a slighly larger diameter so that has a negative impact. But placebo or not car seems to like it seems a lil more responsive certainly less slop and while its very low the rotational aspect seemed to justify the cost IMO. 2 Piece rotors great sure but the replacement cost of disc rings is making me a lil hesitant.
AC seems like an easy low hanging fruit thing that is up front so that should have a good impact on the balance. Then Im looking into lighter FMIC and chromoly front bumper beam (STM unit) or perhaps fabbing up something custom from aluminum. I can go on and on.
Also, newb question but what do you mean by beyond the wheels? Are you referring to sprung weight?
The reality is that I want to drop as much weight as possible but do it in the best places as well as go about doing it tactfully such that I dont swiss cheese my car and also dont care to spend thousands upon thousands to accomplish it. So while I would like to chip away slowly its the cumulative where it will really start to show.
The roof seems to be good bang for the buck although cost of entry is a lil higher and the necessary work to get the job done is a lil more involved.
I just did the driveshaft, arguably rotational mass granted some comes from dropping one mount and the AL shaft does have a slighly larger diameter so that has a negative impact. But placebo or not car seems to like it seems a lil more responsive certainly less slop and while its very low the rotational aspect seemed to justify the cost IMO. 2 Piece rotors great sure but the replacement cost of disc rings is making me a lil hesitant.
AC seems like an easy low hanging fruit thing that is up front so that should have a good impact on the balance. Then Im looking into lighter FMIC and chromoly front bumper beam (STM unit) or perhaps fabbing up something custom from aluminum. I can go on and on.
Also, newb question but what do you mean by beyond the wheels? Are you referring to sprung weight?
The reality is that I want to drop as much weight as possible but do it in the best places as well as go about doing it tactfully such that I dont swiss cheese my car and also dont care to spend thousands upon thousands to accomplish it. So while I would like to chip away slowly its the cumulative where it will really start to show.
