Weight reduction (titanium)
Posted by leftovr@reddit | projectcar | View on Reddit | 60 comments
Picture for attention to my lightweight toys (zzw30 & zc32s)
My project car is a Toyota mr2 (zzw30) I know not the most loved gen but I love it. Since I live in Belgium and engine swaps, turbo etc isn't allowed I've been mostly busy with dialing in the suspension and mainly weight reduction to get some performance out of this little frog.
Most of the heavy hitters that I've done:
Lightweight sparco buckets
Lifepo4 battery
Lightweight wheels
Prius calipers (alu instead of steel)
A lot of interior stripped
Some DIY carbon panels (drip tray, coil covers etc)
Now I don't want to delete all comfort like ac and radio as I use this for road trips (Italy, Poland, Croatia, Switzerland)
Since finding a trusty supplier in the Netherlands for titanium hardware I've gotten a bit obsessed with this. I regularly measure threads, lengths and ofcourse weigh them and order the corresponding bolts / nuts in grade 5 titanium. Only do this for non critical hardware. Could've gone aluminum for a lot but yea..
Now I'm wondering where do you draw the line with what needs to stay steel hardware? I'm no engineer but do my research. Has anyone gone full send in terms of titanium bolts? Some personal insights would be greatly appreciated!
JackTheBehemothKillr@reddit
From an engineering standpoint, when running titanium hardware you very well could run into significant galling on any and all threads of dissimilar metals. Been a while since I looked at it, but potentially with Ti on Ti hardware.
Gonna want to invest in some antiseize.
JCDU@reddit
Go watch Bargain Racement by the Bad Obsession boys on youtube, they lightweight a Citroen C1 for a race series.
While it's good to think about every little gain, the truth is there's usually a ton of far easier things you can do to shave that weight off - like instead of replacing a load of bolts with titanium to save a few grams, just half-fill the washer bottle to shave 1kg off...
leftovr@reddit (OP)
True, I already ordered a windshield washer bag. Should be only 300g and holds max 1l of fluid.
Thanks for the recommendation, I'll check it!
JCDU@reddit
What I learned when helping a buddy build race cars was just stop and look at everything - every bracket, every component, etc. and ask if it needs to be there or could be replaced with a lighter and/or simpler version.
Most cars have a ton of stuff that's there for one or two models - brackets that hold a switch or relay for the heated seats that aren't fitted to yours, stuff like that.
It's also common to unwrap wiring harnesses & strip out wires that aren't needed, the serious boys replace the wire with lighter/thinner stuff and even re-route to make it shorter.
On older cars you can replace the bulbs with LED and then cut down the gauge of all the wires by a load if you're being really pedantic.
Replacing glass with lexan can save a lot but really sucks on a daily driver in winter as it fogs like a bastard.
It's just getting your head into that thought process really - but look for the big easy cheap wins before you spend $1000 on some fancy carbon fibre & titanium part that only saves you the weight of a cupholder.
Also - don't assume factory = heavy, sometimes their crappy plastic part is actually way more efficient & lighter than you could fabricate it in alloy.
leftovr@reddit (OP)
Thanks for the advice, time to add this stuff to the whiteboard!
Looked at the lexan windows because there's a kit for my car. also inspection problem ofcourse.. Also a lot of the big things have been done, the titanium part is more like if I replace the bolts why not keep em from rusting and save some weight.
Don't know the pricing for you guys but the normal grade 5's aren't super expensive in common sizes. Stealer ship already got me on 4 Steel strut bolts and nuts, this cost me €160/$190.
Also I'm quite hyper focused on stuff like this so I tend to weigh everything. Expensive carbon panels are not my thing. I tend to fabricate stuff myself as I also really enjoy the process!
Pyropete125@reddit
Drill holes everywhere
leftovr@reddit (OP)
Speed holes it is then! If I can hide them lol
Dark_Guardian_@reddit
except for the places where you can just remove something entirely
I don't think I actually drilled any holes in my subaru, 800kg though
Pyropete125@reddit
Dark_Guardian_@reddit
whats the panel doing? no panel is lighter than panel with holes
Pyropete125@reddit
I agree but the dzus fastener brackets and tow hook too the aluminum with the holes
Tommy_Blues@reddit
Would a stealthy 2ZZ Swap be possible? The engines are very similar, you could argue it won't get detected. I understand legislation is a problem. Germany is world famous for TÜV after all. Same same but different.
Tr0z3rSnak3@reddit
Just dip your car in acid to lose a few lbs like they used to in Nascar (just kidding don't do this) Maybe a tune for more power? You said turbos and motor swaps are bad but maybe a set of cams could eek a bit more power out
leftovr@reddit (OP)
Standalone is waiting in my basement for the harness to arrive, it's probably not going to add a lot of power but it's more trial stuff. The smog inspection is quite strict here, so it'll probably first be trying to tune it and pass inspection.
Because ofcourse again, standalone/engine tuning illegal.
SleestackMcGee@reddit
How involved was the Prius caliper swap?
PulsarGTI@reddit
It's a bolt on replacement, very easy. The stock MR-S caliper bracket stays, it's just the caliper itself that you replace.
SleestackMcGee@reddit
Sweet. I wonder who figured that out.
leftovr@reddit (OP)
A guy on spyderchat, the weight reduction thread node wrote is quite insightful. Only some stuff not applicable here lol because of legal issues
curious-chineur@reddit
How old is your car ? By chance you may get simplified inspection because of that.
You van possivlybslide something because of that collector status.
It works for heavily modified vws.
If you pick the right eu country you can get your certification there and bring it back home on sheer admin. Equivalence.
Maybe yes maybe no. Not sure at all. Belgium is supposedly not as stringent as france for example.
leftovr@reddit (OP)
Not old enough, 22 and it needs to be 30. Don't know the laws in France but oldtimer inspection is indeed much easier but some things still don't fly.
Friend of mine has an e30 which can't pass the inspection without the right connections and enough money and even then it's not foolproof. He passed 2 years ago and this year he failed
curious-chineur@reddit
It is the same now 30 years. Beforebit was 25. Cannot you find more lennient / lax onspection centers ? It is common in France. Somebwill be pretty "up tight " some may be much less...
leftovr@reddit (OP)
Not really much difference in between because there's quite some monopoly going on. I have to be patient for 2 years and then all registered mechanics will be allowed to do inspections, so I hope for the best
danny_ish@reddit
The american in me wanted to laugh at the roadtrip distance, considering these are all weekend drives we make often (anything under 12 hours 1 way is normal to some of us) but honestly i value comfort above all else. A/c, cruise control, smaller rims and more sidewall on my tires.
As for the bolts- as a mechanical engineer who works in automotive, id say start with looking at torque values. Sometimes we use bolts because assembly is easier, sometimes we use them because we really need high clamp loads. Almost any bolt that is a lower torque values would probably be safe to swap over to titanium, especially if it was a lower grade bolt to start with.
So yeah, look for 4.6, 5.8, and maybe some of the 8.8 grade bolts. If you have the same fastener used elsewhere on the same assembly and it’s a low torque in some areas and a high torque in others don’t replace the high torque ones but replace the low torque ones.
leftovr@reddit (OP)
I get why you would laugh at the distance here I'm considered as crazy lol. Would go further if my gf could handle it
And this is the kind of answer i needed, it's time to whip out the repair manual and start checking those torque specs. Greatly appreciated!
therealhairykrishna@reddit
I loved my Mk3. You don't mention it, but I assume you have an underbody brace for it? If not, you should
leftovr@reddit (OP)
I love it so much, and yea different bracings installed. All of them custom 7075 t6 to keep it as light as possible ofcourse!
myfishprofile@reddit
It’s crazy to me how different car cultures are based on local laws
Sorry I don’t have much to add as I definitely fall into the “add power” camp of hot rodding.
Jmauld@reddit
Removing weight is adding power
myfishprofile@reddit
No, it’s not. It’s removing weight
They’re fundamentally different approaches With unique build strategies
While you can achieve similar goals they’re not the same
Jmauld@reddit
They’re the same.
SupraMK4@reddit
A 250 hp 800kg car and a 500 hp 1600kg car will drive insanely different.
Jmauld@reddit
Lots of things affect the way a car drives.
leftovr@reddit (OP)
Would love to be in this camp but removing a turbo yearly and everything related to it would be a pain.
Not to forget when police notices you're fucked, if you get in a car accident and you're not at fault insurance can deny your claim. Police also can take you to court..
So yeah a small rotrex or little turbo have crossed my mind numerous of times but sadly not happening
myfishprofile@reddit
I definitely get it, nothing to be done about super restrictive places where the risk just isn’t worth the payout. I’ve been through a bit of that myself but nothing close to that degree.
Which is what eventually led me to my other hobby, motorcycles 🤣
chubsplaysthebanjo@reddit
How much cheaper is going on a diet for the pounds that you'll save by swapping the hardware?
leftovr@reddit (OP)
Knew I was going to get these answers, not as common in Europe. It's cheaper but I don't need a diet. Gym 5/week, 5'8'' 165lbs at 12% body fat.
Illustrious-Art-7465@reddit
Whether you want to or not it would be a lot easier to lose 5 lbs and be at 160 than to replace all the hardware to save 2lbs
chubsplaysthebanjo@reddit
Good work! I think you should treat yourself to a titanium exhaust
silent_sparrow_909@reddit
Nice backpedal too... smh
LiqourSnatch@reddit
Right? 5'8" he's still got an easy 20-30 lbs he could save before he's under weight, 40-50 lbs before things start getting serious
danny_ish@reddit
Goddam. Im 5ft 6in and 190 lbs, muscle isn’t light! (But i do have a gut)
leftovr@reddit (OP)
I know I could do it but I actually like my physique now. I've been underweight for most of my life so getting here was not an easy journey.
leftovr@reddit (OP)
Thanks! Inspection would also murder me if I came with a titanium exhaust.. Belgium is a shit show for project cars and I'm trying to stay within legalish boundaries.
To give an example, you want to lower your car? You need certificates from the manufacturer specially issued for Belgium, you need a report from a registered mechanic who installed them. lastly you need to pass a special inspection in terms of car geometry (failed it 4 times)
chubsplaysthebanjo@reddit
That's insane. You can make a car from scratch in the US and get it fully inspected and registered. I wish you luck in skirting those regulations!
silent_sparrow_909@reddit
This is such an asshat reply. Might as well ask f1 teams why they r/d lighter more aerodynamic parts, instead of just highering skinnier drivers. They are both lighter and more aerodynamic.. that way they could just race stock cars.
AKA_Squanchy@reddit
He’s European, I’m sure he’s already fit lol
leftovr@reddit (OP)
Gave me a chuckle lol, nice Z!
crappyroads@reddit
If you want to get really geeky, I'd recommend you start removing non-structural interior compenents and see how much they weigh, then see if you can get anywhere close by switching hardware. You can find parts diagrams for most cars so I'd pick a quadrant of the car and count up the fasteners, multiply by 4. I'd be willing to bet that you could get the same weight savings from removing a couple interior trim panels. There's not actually that much weight in fasteners. As others have said, titanium has some really great properties, but the eye-popping cost of it will add up quick.
Do you already have light wheels?
leftovr@reddit (OP)
Thanks for the insight, not much interior to be stripped a lot is already taken out. And yes sl04's fronts are 4.5kg (10lbs) and rear 5.2kg (12lbs). Was looking for ssr type c's but unobtainable here, and regamasters don't come in 15's
crappyroads@reddit
Bummer about the car inspection rules. I have a friend in Switzerland and it's exactly the same there. The US sucks in a lot of ways, but at least we can work on our cars.
Do they make aluminum suspension compenents? Aluminum subframe? It seems likely that even swapping one or two of those pieces will get you more savings than titanium fasteners.
leftovr@reddit (OP)
Only steel suspension components, not really much aftermarket for this platform but yeah. also everything suspension that's not oem = illegal lol. My white line sway bars are not allowed so have to swap them out every year for oem.
I was already thinking about fabricating my own aluminum brackets etc because can be hidden and it's not structural. Done 7075 t6 bracing underneath (also comes out for inspection)
umdv@reddit
Just paint sway bars black 🤷🏻♂️ And measure weight of subframe, maybe titanium would be a major reduction. Also painted black for inspection reasons
leftovr@reddit (OP)
Tried it with the sway bars painted black, they saw the adjustment holes so it was instant fail.
They really aim to fail people because that's how they earn money. Like for every allowed modification you have to pay extra they call it tuning inspection, different shift knob? €7 please, Exhaust with all the needed documents? Again €7 please, and it's not once registered it's permanent. Every yearly inspection you got to pay the tuning inspection again.
aliennick4812@reddit
the possibilities are endless with enough money. depends person to person. some people can drive an open top tractor to work every day and some people need heated seats and ac etc.
leftovr@reddit (OP)
For sure! I'm more wondering where titanium lacks strength. In high level race teams the whole car gets checked every event so they can do all the fancy stuff.
I was hoping to see if someone had experience with critical bolts swapped to titanium and how well they hold up. Suspension bolts etc
darianbrown@reddit
Titanium is usually a stronger fastener material. Really, the concern would be damaging the parts you're threading into.
RIF_Internet_Goon@reddit
Im a simple man...I see Mr2/MrS I upvote.
Entire-Extreme7327@reddit
Titanium is outright better in so many applications, especially if you have titanium nut and bolt combo. It is much stiffer, so there is very little give. With that, use split washers or star washers to prevent from coming loose from vibration. I would also avoid titanium bolts into threads in cast materials, as the titanium is so stiff, it can gall and damage threads. Consider this: if a thread is going to get damaged, which thread will likely give way first? And, which damaged thread are you ok fixing?
Hot-Bluebird3919@reddit
What has your research uncovered? Did you find out about titanium and high temperature creep? That requires extra measures for bolts running at high temperature. Did you find out that titanium yields at a lower stress than steel? It’s great for corrosive environments and some high temperature applications. Realistically how much steel could be replaced by titanium and how much weight would that save you? Is it more or less than half a tank of fuel? The MR2 is relatively light to start, you might consider other options such as composites.
leftovr@reddit (OP)
That's why I've only done non critical bolts. By this I mean interior bolts, undertray bolts etc.
Thats why I'm already dabbling in fabricating carbon panels (illegal again but hideable)