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Discussion Starter · #1 ·
I am looking for LSD/ATB options on the 6sp manual.
From what I have been able to learn there was the Wavetrac (did many people buy these?) and Quaife ATB, but were there any other options available?
I have heard that Gripper made a one-off plate diff for a rally car, but these are not as street friendly as a torsen ATB such as the Quiafe.
Where would be the bast place to look for a quaife/wavetrac?
 

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Basically Stock
2009 GS Turbo. 2007 Mid Engine GT
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Most popping up these days are on eBay from guys who bought them, but never installed. Without demand, there isn't likely to be another round of the Quaife ATB. Wavetrac I didn't talk to. Gripper is news to me, and I don't think you'd want a plated LSD in a front drive anyway as it would have to be super mild to not ruin cornering ability, and fast wearing.
 

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Discussion Starter · #3 ·
Thanks for your reply.
Quaife did offer to make a one-off ATB, but the price reflected the 'custom' nature of a one-off order and I've never seen anyone mention using a Wavetrac diff.
I did follow up a lead in the for sale section of this forum, however the seller was not willing to provide details of use and only one grainy picture and then wanted payment via family and friends paypal that offered no security. It seemed a bit dodgy, so that was a dead end.
The Gripper plate LSD is being used locally in a Diamante/Magna dirt rally car - torsen style diffs are not that useful in such circumstances. See below
So my best option is likely to haunt ebay?
.
 

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Basically Stock
2009 GS Turbo. 2007 Mid Engine GT
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Are you using it on an Eclipse trans in a front wheel drive layout? I'm curious what your project is.

I run a Quaife ATB on my rear drive GT. When I was doing it, I found something odd. The documentation that Quaife gave me on it has the part number "QDH7B" and lists it as being for a 2wd turbo Eclipse. When I looked up the number, I found it listed for a 3000gt even, such as below


It's odd that Quaife would give me the info on the QDH7B if it's not the one that is to be run. I also was asking specific to manual trans on the GT. I'd shoot them a message if I were you, as that dif is definitely still available in places, just not marked as for the 4G eclipse anymore. I had also asked them previously about fitment in the auto trans, which they replied that they don't believe it's compatible (originally I was going to go 5A with my mid engine build for simpler shifting setup and paddle shift, but lack of dif options made me go manual)


On the forum however, I found these two posts relating to the auto trans

"The Quaife QDH7B is the best for our drivetrains.
But it needs machining of the crown wheel, the splines on the driveshafts need resetting and case hardening. "

And

"The two of us guys in this thread that have the superchargers fitted also now have custom Limited slip differentials on our 380/9g auto transmissions.

Basically you get the quaife QDH7b ATB differential and have it machined to fit as well as re-splining the driveshaft splines."

Hopefully that helps. It's as far as I'd ever had to dig into the situation.
 

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Discussion Starter · #5 ·
Well the short version is still quite long ... some time ago I used to be a publisher/editor of a motorsport magazine and I had a project within it to make my own mid-engine spaceframe sportscar. This is mostly due to the fact that at 6' 8" I cannot fit into a MR2/911 etc with a helmet on. Anyway, at the time Mitsubishi Australia had started making the 380 - the 6G75 Galant for the local market. Some of the engineers were racers and read my magazine and when I mentioned my regard for the 6G75 and manual transmission I was fortunate enough to get the complete running gear/harness etc from one of their test cars given to me. Then with the chassis mostly made life intervened and being a dad became far more important than running the magazine/making cars and it was all put on hold. 10 years passed and I'm restarting the project as I'm finishing off a couple of others sportscars.
So think of a Noble M400 with a bit more track and wheelbase and between 900-1000kg and you'll get the idea.
As for the LSD I've been told that the 5sp manual in the local Galant/380 is a F5M51-1-S5P. One of the ex-Mitsubishi test personnel, who used to race a Magna/Diamante now runs a Mitsubishi breakers buisness - he has reported that this transmission is different to the previous Diamante in that it uses the same gears as an Evo5 and the same QDH15B ATB as the 6spd from the 4G Eclipse. So the challenge is twofold: over the next two years find a final drive higher than the 4.11:1 in the manual 380 and find a LSD option. The 4.11:1 final drive will be a bit short for a smaller car 600kg lighter than the donor car, esp if forced induction is planned (it is).
I'd love to have the 6spd manual, but it was not available locally and shipping from the USA is hugely expensive ATM and finding trustworthy suppliers in the USA is not that easy for such a part.
I will mention that 6G75's are having a resurgence locally, as they are being transplanted into Diamante's and Lancers.
 

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Basically Stock
2009 GS Turbo. 2007 Mid Engine GT
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You're talking to a guy with a mid engine 6G75 powered car in a custom (3/4) tube chassis... This is hilarious. You're a nut just like me. I wanted an Alfa 4C, but can't fit in those with a helmet on at only 6'... Mine's sitting at 2660lbs right now (~1206kg) and has about 200lbs to shed still without doing anything crazy, with an Eclipse body. My next project I've been toying with in design phase is a 600-700kg 6G75 powered off road buggy (I've got complete eclipse harnesses, computers, engine, cluster, ignition, steering rack, steering column, key, four front stuts and even an ABS module if I wanted, might make it street legal). If you've got pictures of yours so far, I'm definitely interested.

I think at 1000kg you'd still have a great time with an NA 6G75. 0-60 I've cracked 4 seconds flat on some old 225mm 300tw summer tires with 200kg more weight. Something sticky back there and a turbo would undeniably be a rocket though (I'd never done a 1/4 mile run with mine, as I've been focused on handling all year and working out small issues, so I don't know how it does there)


I'd like to help you get a 4G 6MT trans down there, but I'm also in Ontario Canada. Much more sensible shipping would be from the west coast to begin with. Car-Part.com is a junkyard search a lot of people use in North America to find yards with the parts, and they could perhaps set up the freight at the yard. I just checked, it seems they also have remanufactured ones listed as well


I find the gearing a little short on the 6 speed while NA already for my local road course (mostly around 80-120km/h, hitting 180 on the main straight 160 on the shorter one that comes out of high speed corners), but decently wide powerband helps make up for it. I've wondered if a 5 speed would have been a better go, particularly when turbocharged (which is also my end goal on this one). A longer final might be the solution, like you're looking into, however.
 

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worth noting the LSD's out there for 3g GT manuals are physically compatible with 4g GS/4cylinder manuals, WaveTrac had identical part numbers for both end use cases, it should also be the case with Quaife's
 

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Discussion Starter · #8 ·
Saber there are even more similarities: the inspiration for me was in part the Alfa Diva, a show car by Sbarro. I've run on the track with 4C's and they are quick - they should be given the VX220/Elise origins - they're very good under brakes and in corners and are a pretty little car, but yes taller people will struggle to fit esp with a helmet!
There's not much to show on the middy (called Godiva), but I'll add a couple of pics of the base chassis when I was doing the welding to give you an idea of the scale. It FEA'd at 22,000ft lb/deg, but you need to treat such figures with =/-20%, it will be stiff enough. Designing a chassis is an interesting exercise, with many competing priorities and doing it gives you a better appreciation of the professional engineers who do this all the time. Building a vehicle like this is bound by many rules in Australia and the whole process needs to be tested and recorded by a specialist engineer, at a substantial cost. One of the biggest challenges is emissions - the 6G75 will be used with the stock ECM/wiring loom, which you know is extensive. It will also have to keep the std exhaust/cats so that I can make the argument that emissions will be unaffected in this use. The alternative is an emissions test which costs over $1000 a go. A big roadbock was getting the engine running without the ABS computer - this was bypassed by some Mitsubhi tech's with two paperclips! So the engine will run, I have the suspension calculated, working on getting a cable handbrake caliper to mount to the Galant front knuckle. This is done using a Saab rear caliper and Mazda disc and a dogbone mount.
The middy project was put on hold while I made a GSXR powered hillclimb car: see picture attached which I am just finishing. This is one of my favourite forms of motorsport as the car club I am a member of has their own track which you can see here from a friends run:
 

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Basically Stock
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This is hilarious. I was watching your friend's videos last winter while deciding if I go double wishbone or re use the stock suspension geometry (came up suggested after some engineering videos and similar cars).

Too bad I'm on the other side of the planet. We don't have much for Hillclimb or small displacement tube car fun here. Typically it's circle track sprint cars if it's small, and V8 tube frame full size trucks/cars otherwise for road course. You guys have some wicked toys.

Is that aluminum you're using, or painted?
 

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Discussion Starter · #10 · (Edited)
The single seat stuff is going to be all new for me. Until I made my own car I was never going to fit in someone else's, I'm not going to be competitive as I'm just too big/heavy. So the car you see in the workshop pic is designed tough so that I can double/triple enter it with my sons/friends and we can compete against each other and it won't fail. Not all hillclimbs are that long or that slow. It's a form of motorsport popular in Europe and we followed suit.
The alloy sheets on my car are structural, 1.2mm thick 6061 T6 alloy which is a challenge to work with. I'm experimenting will adhesive with them, using a structural acrylic adhesive similar to Plexus MA310 and a primer. This has much better temperature range than epoxy - I'm not familiar with Ontario, but we have frequent days of 35C+ and a car in the sun waiting for a run gets hot pretty damned fast - hence the heat capable adhesive choice. I'll a composite body to flop on the top.
This might give you an idea of the cars, all of which are home-made:

As for suspension, struts can work pretty well, just look at Porsche's. The challenge may be to get something on the front that works with the back.
I happy to tell you what process I followed, but I'm not suggesting that it's best practice or you should do the same.
 

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Basically Stock
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I'll probably go shocks on my buggy just for the off-road side of things and availability of materials. Similar to my GT, I'd just have to build strut towers again, mate them to the chassis, and can use them to set alignment partially. Thank you though

Would a construction urethane hold for your needs? Urethanes tend to be fairly heat resistant, strong, and have a good adhesion. I actually use construction urethane from a tube (PL brand, not sure if you have it) to fill motor mount bushings cheaply and easily to stiffen them.

Ontario definitely gets 35c and hotter days, but not many of them. We see about as many +35 days as -25 where I'm at. My first track day in my GT, with a non burped heater core and holes in the firewall, started around -30c and warmed up to -25 hahaha. It was chilly, and the heat only worked above 4000rpm to start.


I checked out that video, and it looks like an amazing time.
 

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Discussion Starter · #13 ·
-25C! No, we don't get anywhere near that even in the snowfields in winter. A really cold day for us will be 7C and max hot will be 45C (rare). Most hillclimbs will stop at 35C as the super-soft tyres don't work and they are very expensive, though ironically it will help me running Yokohama AO50's.
I don't know the PL brand, but common here is Sikaflex - a PE adhesive with lots of different grades. I've used it for the driver's bulkhead (firewall) but like all adhesive's it's a trade-off. I used PE there as it's got great gap filling properties and I needed to seal the firewall to meet regulations. PE adhesives need a thick bond line (I think around 2mm was recommended for panelbond sika) to work well and the adhesive is quite flexible (low shore hardness and long elongation numbers), which is not what I wanted on the alloy panels, which are structural and intended to add stiffness to the chassis. Many have used this adhesive in their cars, but then you need to rely on a mechanical fastener to hold the panel - usually rivets every 30-50mm, which can be a lot of work. A panel done this way relies on the rivets and the PE helps limit the loosening of the panel over time, but is not the primary bond and eventually the rivets can loosen. If you look at the number of cleco's in the side of my single seat car you'll see that they are spaced every 100mm, they are that far apart as they are not really structural in shear, but are there to limit peel as the SA is the primary joint. The SA adhesive has a much higher shear performance (20-30mpa) as well as higher shore number (around 70), so if you try the 'fingernail' hardness test - the PE feels like moderately hard rubber, but the SA feels like hard plastic - much stiffer. SA adhesives are forgiving on the prep side of things in comparison to epoxy, but the downside to SA adhesives is the working time: structural epoxies can have a two hour working time and what I use, which is a long set SA, is 12 - 15 minutes.
Having said all of that - my car is an experiment to test for the mid-engine car. I've never used SA in this role before and it is a relatively new chemical form of adhesive. I could find no one who has used it for this purpose, in part because it's new and also it's twice the price of PE at $100 for 400g, though it's much cheaper than equivalent epoxy.
If I was gluing panels onto a car for bodywork I'd use PE every time, though if you mess up PE it's like doing a bad nappy change on your child - the stuff gets everywhere!
I'd go long double wishbones on a buggy - I'm jealous of your access to the USA market, as there is so much choice with things like shocks, or at least the online catalogs indicate that.
Getting the weight distribution forward in the mid-engined car was difficult and it's strongly rear weight biased.
 

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Basically Stock
2009 GS Turbo. 2007 Mid Engine GT
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-25C! No, we don't get anywhere near that even in the snowfields in winter. A really cold day for us will be 7C and max hot will be 45C (rare). Most hillclimbs will stop at 35C as the super-soft tyres don't work and they are very expensive, though ironically it will help me running Yokohama AO50's.
I don't know the PL brand, but common here is Sikaflex - a PE adhesive with lots of different grades. I've used it for the driver's bulkhead (firewall) but like all adhesive's it's a trade-off. I used PE there as it's got great gap filling properties and I needed to seal the firewall to meet regulations. PE adhesives need a thick bond line (I think around 2mm was recommended for panelbond sika) to work well and the adhesive is quite flexible (low shore hardness and long elongation numbers), which is not what I wanted on the alloy panels, which are structural and intended to add stiffness to the chassis. Many have used this adhesive in their cars, but then you need to rely on a mechanical fastener to hold the panel - usually rivets every 30-50mm, which can be a lot of work. A panel done this way relies on the rivets and the PE helps limit the loosening of the panel over time, but is not the primary bond and eventually the rivets can loosen. If you look at the number of cleco's in the side of my single seat car you'll see that they are spaced every 100mm, they are that far apart as they are not really structural in shear, but are there to limit peel as the SA is the primary joint. The SA adhesive has a much higher shear performance (20-30mpa) as well as higher shore number (around 70), so if you try the 'fingernail' hardness test - the PE feels like moderately hard rubber, but the SA feels like hard plastic - much stiffer. SA adhesives are forgiving on the prep side of things in comparison to epoxy, but the downside to SA adhesives is the working time: structural epoxies can have a two hour working time and what I use, which is a long set SA, is 12 - 15 minutes.
Having said all of that - my car is an experiment to test for the mid-engine car. I've never used SA in this role before and it is a relatively new chemical form of adhesive. I could find no one who has used it for this purpose, in part because it's new and also it's twice the price of PE at $100 for 400g, though it's much cheaper than equivalent epoxy.
If I was gluing panels onto a car for bodywork I'd use PE every time, though if you mess up PE it's like doing a bad nappy change on your child - the stuff gets everywhere!
I'd go long double wishbones on a buggy - I'm jealous of your access to the USA market, as there is so much choice with things like shocks, or at least the online catalogs indicate that.
Getting the weight distribution forward in the mid-engined car was difficult and it's strongly rear weight biased.
You wanted weight in the front? I'm at 48:52 on my Eclipse and love it. It responds very well to trail braking like that while letting me get on the gas again very quickly. I kept all the mass I could between the axles so the moment of inertia would be very close to promote rotation and lessen yaw forces on the front tires to give more ultimate cornering grip.

In the video I'm seeing a lot of cars that seem like they could benefit from a bit of weight in the rear as they don't seem to be grabbing well enough in the back on corner exit.
 

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Discussion Starter · #15 ·
Blank sheet design might be a bit different, given the added variables. Even with the 6G mid-engined car's very solid structure, I'm struggling to get weight up the front without adding more weight to the car just due to packaging constraints. I did a spreadsheet and weighed all of the components and calculated the CoG of each and then added them to the design. This helped with wheelbase calculations and helped with F/R tyre selection and calculating the F/R understeer budget (called a Bundorf Analysis)- this bit I had help with as I don't fully understand the intricacies of tyre friction. The aim to have a steady understeer condition with varying friction coeffecients (dry/wet road etc). The other factor with this was making sure the steering rack ratio was no too fast, as over control is very common and the 'tank-slapper-spin' is best avoided.
One challenge is sump modification: locally the 6G75 sumps suffer from oil starvation in corners (when the car is driven hard on motorsport tyres) as there is no baffling to control surge - not sure if the MIVEC engine is better. Local Diamante/Magna racers have made semi-dry sump setups using a two stage scavenge pump to an external tank and the original pressure pump drawing from the tank. Personally I'd love to drop the 6G lower if I could to lower the CoG, but the sump is pretty much level with the transaxle and I don't have the ground clearance. At this stage I'll be notching the sump, adding an X baffle and adding capacity to the sides if I can.
The hillclimb cars are a challenge, with the mix of mechanical and aero. Bryant park, where this event is run is a slow track (reducing the aero impact) and has significant elevation changes, which leads to occasionally abrupt weight transfer - you'll see some cars get loose at some corners when suspension travel. More rear grip could mean slower rotation and this migh mean a slower lap on a track with this many cornering events. From memory there was less than a second covering the first 3-4 cars. Greg's run here is one of the faster cars from a decade ago - things are lighter and faster now:
 

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Basically Stock
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That was a great run to watch. Very well set up, and good driving skills.

Part of what I was seeing could also be from spring frequencies. Too fast or slow a rear vs the front, and itll slide when upset. I went with about 15% faster frequency in the rear (2hz front 2.3hz rear) and it works great on my local track, but your track looks smoother.

For 6g oiling, aside from a custom dry sump there's accusump, which is basically just a pressurized bladder in a tube pushing against the oil pump with a reservoir. When pump pressure supply drops below the bladder pressure, the bladder pushes the oil reserve into the engine.

What sort of weight balance are you going for? 40:60 has become fairly common in high end motorsport vs the 50/50 of the past. Also where to do put your fuel?
 

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Discussion Starter · #17 ·
Spring rates and suspension setup all changes when you start getting downforce - there's a 6' wide triple element wing on the back and a dual element on the front. Keeping the car off the ground and bumpstops is very important. Similarly balancing grip with the ability to rotate the car in a corner is an issue - too much rear grip and you get understeer, which means you're off the throttle in early corners, until your fronts heat up. If you've got too much grip then you'll understeer and have to feather the throttle to make the corner and thus lose time.
Greg in the video is a talented punter and knows his cars very well. He's also used to dirt-bikes, so stays on the power when it slips and gets squirrely ... where I and many others back off.
BTW those tyres around the track are full of dirt and do not give an inch!
The 6G spaceframe car is roughly 60/40.
 

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Basically Stock
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That's why I do spring frequency for grip, not spring rate alone. Spring rate plus geometry is good for figuring out ride height drop under load however. When I did my setup, I was accounting for up to 600lbs downforce, split with a 50:50 force. I am aiming for 50:50 to keep my car feeling the same with and without downforce at play. I'm 3D printing a wing element to use as a core right now good for about 270lbs downforce at 40lbs drag at 160km/h in clean air. Nothing crazy, but it all adds up.

Mentioning tire temperature is a good point. I don't do hillclimb, so I can get some warm up laps in on road course. You don't have such a luxury.

60:40, so front biased? Or do you fellas in Australia show it the other way around? Front biased is something I'm very used to seeing people get rid of, even on FWD cars, on our tracks for better times
 

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Discussion Starter · #19 ·
LOL, no rear biased - it was late when I wrote.
Hillclimb tyres are the softest you can get, specially made by Avon. When new they actually feel sticky and you can press a coin onto them and it will stay there. It will cost you upwards from $2000 for a set and what I've been told is that you get 5 really good runs from them, but if you want to make up that second on the time sheet there's not other way to do it. The tyres settle down after that and get used for the rest of the season. Doing a burn-out to warm the rears is accepted, but can create issues as you've got to run hard from the start and you can see from Greg's run that he's comfortable with slip.
I'd be interested to hear why you went mid engined in an Eclipse bodyshell?
 

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In short: I'm poor and wanted a project that could play with faster cars, while also being street legal (it would have been easier to make a fully custom tube frame car street legal, I learned later, but I managed and it's all declared and legitimately plated). In any case, it feels to me like a true Mitsubishi parts bin supercar


What I could afford wouldn't handle how I wanted, and I was quite familiar with the platform in general from a custom turbo setup I did on my 4 cyl Eclipse I owned. I knew I needed something that could handle better, as my buddy in his Civic race car on 200tw track tires was running the same lap times at 2600lbs and 170hp as my 2800lbs 400hp car (although, on 300tw all seasons). Drunk with friends one night I threw the idea out there, we all had a laugh, then my friends found out I actually started buying cars to cut apart to build it (starting with a buddy who had JUST blown his motor on his GT of EXACTLY the trim I'd need for the project, and was moving ~42 hours drive away per google maps). Had I had (~2000+) 911, NSX, or Viper money I'd probably be running one of them in fairness. Beyond all that, it was a nice summer project to pick up

The changes in grip and handling are fantastic, it feels a lot like driving a 4C, except with less body roll, more power, and my head doesn't touch the ceiling. Comfort wise isn't bad with the digressive valved shocks. Normal valved wasn't doing it for me. I'm not a big 0-60 guy, but even on 300tw basic summer tires it has done a 4 second flat 0-60 time, which outdoes my 400hp Audi TT Quattro (although it is just a daily on all seasons). It's well balanced, and the control is fantastic. Even in a slide (fastest slide was about 140 so far during a high speed left/right pair of corners) it's not jumpy, it's smooth and easy to correct. Since I removed my rear sway bar, I've been able to come onto power unnervingly early in corners. It takes a few laps every time I'm out to get the confidence to go full throttle as soon as I hit my apex, but typically it's capable. Prior to that it would slide.

There are definitely challenges involved, and using the OEM suspension is both a regret and something I appreciate depending on the day. The control arm sweep on the MacPherson is just awful, hitting parallel to the ground with as little as 1" of travel on my winter autocross setup (~4" wheel gap), or being in the negative on my summer setup, ready to eat away camber (flush with fenders). Right now I'm leaning into it as a rally car more than circuit racer due to the poor suspension choice for a low ride. In the rear when I was designing the tube frame, I did raise the suspension mounting up by about 1.5", so it helps a lot there. But it's still a major weakness.

Even with it's weaknesses, and constant alterations, it made me very happy when I paced an off the lot 911 Carrera in the corners and took them on the straights on a set of old summers. Even if I could only maintain that for 2 laps due to lack of oil cooler, it showed I'm on the right path.
 
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