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Old 11-04-2006, 07:46 PM   #1
flyboymike
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Default Suspension guide from December 2006 issue

I got to tell you, I don't think it was very good. There were a few critical concepts that were not fully explained or left out and there were a few outright errors. The overall philosophy seemed more like "throw parts at the car" instead of "engineer yourself a suspension." Since you are a Subaru specific magazine, you could have gone into some details that work specically for Subarus.

The heart of any strut/spring or coilover system is the damping. The only advantage that a coilover would have over a good damper with an equivalent spring would be cornerweighting, which is only practically useful to an experienced driver. No mention of single or double adjustability, or even what "rebound" and "compression" mean, no ballpark figure for how much lowering is too much, no discussion of the control arm inversion problem that comes with too much lowering, and you jumped on the coilover bandwagon without even showing any of the high-end ones with good valving that actually can be comfortable and fast.

Your swaybar section was generally right, but did not mention any of the reduction in camber loss benefits that can accrue from a large front swaybar.

Your explanation of the ALK was very, very incomplete. Its purpose is not to add caster or to provide a less squishy bushing. These are side benefits. Their main purpose is to remove the anti-lift and dive geometry from the front of the car so that you can get some weight transfer and get traction coming out of corners.

Your alignment section had the most egregious error. Toe out helps turn-in and is destabilizing, while toe-in is stabilizing. Go hit an ice skating rink and see what happens when you put your "toes out".

This suspension geek is very disappointed.
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Old 11-04-2006, 10:27 PM   #2
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This guide is only a primer. In my experience a toe-in gives a darty feel with more immediate turn-in while toe-out is just the opposite. I will look into this and make corrections where needed.
This is not meant to be the end all be all guide, as was stated in the article. It is merely meant to be a starting point for those who have never purchased or thought about their suspension in any meaningful way before.
We could have gone into much greater detail and then there would have been no space for any other features.

We will be doing more in-depth this year on a variety of topics. Re-read the into, I think you will find that we state very clearly the intent of the piece. All journies start with a begining, and that is just what this article was.
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Old 11-04-2006, 11:49 PM   #3
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I have to agree with the first post. I read the article while at a friends, and it re-affirmed my feelings of why I don't have a subscription to this mag. It seems anything technical is geared toward the average Joe with zero mechanical and technical skills. Bland as hell with nothing worth chewing on. What's worse, is the Average Joe will come away with incorrect info and generic assumptions.

It would have made a great article, had this been SuperStreet Mag, and it was 1998.

Chris H.
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Old 11-05-2006, 12:17 AM   #4
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Sorry you feel that way guys, but the fact of the matter is that the guide is a primer. Glad you knew what was up with your suspension back in '98, but after seeing TONS of tuner cars with huge HP and no suspension mods at all, we felt that a primer was the way to go. That and we have never done one. The article was not meant for "gurus" it was meant for the average joe. If that is lame, then I guess we are lame.

And please keep listing our errors as you see them so that we may print corrections.
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Old 11-05-2006, 01:39 AM   #5
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Well, here's the thing. I think you kind of went at it backwards. You examined each part and what it does, instead of the problems with the Impreza suspension and how to address them. You said "here are the parts that will make it handle" instead of "here's what needs fixing, and here are the rules to follow to make sure you actually fix it." My primer would go something like this:

You've probably heard all the types of suspension bits there are out there. You know there are swaybars, struts, springs, coilovers, and camber plates. Perhaps you've heard about anti-lift kits, endlinks, and balljoint extenders as well. So, what the heck should you be doing to your RS or WRX to make it handle better? Here are a few simple rules.

1. Whether springs or coilovers, do not lower more than 1.5 inches. You will reduce the available bump travel of the suspension. You will also, in essence, pre-deflect the suspension to a part of its camber curve where you will lose negative camber, and therefore lose grip, as you take a set in a corner.

2. Match your springs to your dampers. The stock struts can handle slightly stiffer springs, but not by much. Tokico, KYB, and Koni all make adjustable dampers that can handle stiffer springs.

3. If you have to ask "do I need coilovers?" the answer is probably no (Rule of Biggly). Adjustable damping is far more useful than adjustable ride height, unless your plans include corner-weighting the vehicle.

4. Whichever end of the car has the bigger swaybar will probably lose grip first. Therefore, when picking swaybar sizes, do not pick a rear bar too much larger than the front. A bigger front bar will improve turn-in and reduce camber loss, increasing overall grip, but particularly in the front. The massive 27mm and up front bars are usually used by people limited by stock class autocross rules and might not be the best solution for people who can upgrade their springs.

5. All WRX and RS owners should upgrade their rear endlinks if going with a bigger bar. Wagon owners should upgrade their front endlinks as well. 2002 and 2003 have weaker swaybar mounts, so those year should upgrade those if going with larger bars.

6. Get a good alignment. Maximize your front negative camber to maximize the grip up front and set zero toe all around. Playing with toe out can enhance turn-in, but you can also burn through your tires much more quickly.

Some amplifying information about dampers
Compression is the wheel moving upwards. Rebound is the wheel moving downwards. Most adjustable dampers are one-way. Some adjust compression and rebound together, which is actually less desirable than just adjusting rebound on its own. Increasing rebound damping will make the car respond more sharply and ride more harshly over bumps. Make the rebound too heavy and you will lose grip. Making rebound damping stronger in the rear than the front tends to promote oversteer, particularly through transitions.

Other bits
Camber plates can be installed with a strut/spring combination, but are sometimes included with coilovers. It's a convenient way to increase negative camber. Some plates also increase caster, or can be flipped to increase caster, which increases steering forces, straight-line stability, and helps gain negative camber as the wheel is turned. All good things. There are also hardened rubber strut tops from Subaru, called Group N mounts, that do not have alignment adjustment. They usually have less NVH than camber plates and are good for removing the slop that is sometimes present with stiffer springs on stock tops.

Anti-lift kits remove the stock anti-life and anti-dive geometry from the suspension. This increases weight transfer, helping the car put down power coming out of the corner. They also add caster and have a stiffer, more responsive bushing. If you intend to autocross, these will put you in at least the Prepared class for SCCA rules.

Balljoint extenders ameliorate some of the effects of lowering on the camber curve, gaining back about half a degree of negative camber. If you intend to autocross, these will put you in at least the Street Mod class for SCCA rules.

A matched spring/damper combination topped with camber plates, a well-thought out set of swaybars with endlinks, a good alignment, and (unless thinking about autocross competitiveness) an ALK and balljoint extenders will simply turn a Subaru's handling around.
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Old 11-05-2006, 02:35 AM   #6
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MeanEditor,

While your concept was good, I believe that your implementation was just a bit off. No worries; the first time out folks don't always get things quite right and practice makes perfect. Be it autox, chess, or tennis.

Now that you know what could be wrong, the first thing to do is to look at how you approach the primer concept itself. Do you want to focus on parts specifically or do you want to focus on inherent problems with the car and the way to fix them? Or approach from another angle of the average joe who just wants to tighten up the handling of the car and fixing suspension issues are just a side benefit?

Flyboymike is spot on in my opinion on addressing the root problems and then the solution and why it works.

Also, Chris H isn't terribly kind so just take that with a grain of salt. Sounds like he had higher hopes than what you guys were able to deliver this first time out.

To expand further upon flyboymike's theme, one could break the primer down to two basic issues with the car:

1) Lack of grip
2) Balance

The car is nose-heavy and grip-limited in the front of the car from the get go. Plus there is a general lack of grip with no camber and horrid body roll. Want proof? Take a stock car and set someone up with a camera and start doing deep turns or slaloms. The issues from bodyroll and lack of camber will rear their ugly head with a quickness.

Visuals will likely be needed to go with any sort of suspension bits; I can tell you exactly how to set up the shots you need (from my own autox experience + my photography experience) to give visual proof of stock vs. any alterations.

Feel free to PM me if you have any specific questions and good luck for future issues.

-Biggly
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Old 11-05-2006, 01:45 PM   #7
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Quote:
Originally Posted by flyboymike View Post
Your explanation of the ALK was very, very incomplete. Its purpose is not to add caster or to provide a less squishy bushing. These are side benefits. Their main purpose is to remove the anti-lift and dive geometry from the front of the car so that you can get some weight transfer and get traction coming out of corners.

Your alignment section had the most egregious error. Toe out helps turn-in and is destabilizing, while toe-in is stabilizing. Go hit an ice skating rink and see what happens when you put your "toes out".
I'm not sure how I feel about a guy making criticisms of technical articles when their criticism includes major technical flaws. Also, in my experience, toe-in can also be very destabilizing.

I do agree that the best way for a primer to be constructed is to have a statement of problem and then a solution, not the other way around.
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Old 11-05-2006, 02:07 PM   #8
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Quote:
Originally Posted by nhluhr View Post
I'm not sure how I feel about a guy making criticisms of technical articles when their criticism includes major technical flaws. Also, in my experience, toe-in can also be very destabilizing.

I do agree that the best way for a primer to be constructed is to have a statement of problem and then a solution, not the other way around.
You're right, my take on the ALK was not correct. I'm glad to have people who do know what they're talking about help me out.
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Old 11-05-2006, 03:37 PM   #9
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I see where you all are coming from, however, you guys are coming from a place where you know the deficiencies/flaws of the suspension. I appreciate all your input and it will probably make it's way into a future issue where we go more in-depth. The point is still that for most owners, and after working sales at a few Subaru performance companies i can attest to this, most enthusiasts think power and not balance, handling etc. This is merely a starting point, a way to get people thinking about suspension and we do address that in the article.

We fully expected some flak on this one, suspension tuning is about as dark and archaic a topic as it gets so when we decided to do a "guide" we figured all the "gurus" would either say "nice basic guide" or, "you guys suck."

Keep it coming, and we will take it all into consideration when we go to the next level.
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Old 11-05-2006, 03:56 PM   #10
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MeanEditor, I have not read the guide, so I can't truly talk about the specific style or content, but I would just like to point out that although it is very common for suspension tuning guides to make some generalizations that lead novices astray, further from true understanding, it rarely accomplishes the goal, which should of course be to help people make their car handle better and understand why. It is reasonably easy to go the alternate path and give only good correct information that is still very basic and leads the novice into a higher realm of understanding.

It would be awesome if future articles keep this in mind! The last thing any community needs is more misinformation just for the sake of getting content on the topic out there.
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Old 11-05-2006, 06:42 PM   #11
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Quote:
Originally Posted by DrBiggly View Post

Also, Chris H isn't terribly kind so just take that with a grain of salt. Sounds like he had higher hopes than what you guys were able to deliver this first time out.


-Biggly
Really? I'm unkind? Was I unkind when i wrote a couple pieces for Driving Sports for free, back when they were trying to get off the ground?

I had no expectations of this article, as I didn't know it was coming out. But it turned out to be like most suspension articles in tuner mags. Generic and a quick read.

Brighten up sparky!

Chris H.
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Old 11-05-2006, 08:20 PM   #12
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I don't think there are enough pages in Subiesport to do a complete suspension guide...

Anyway, I thought the article was superior to any other Subaru Suspension article i've seen published.
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Old 11-05-2006, 10:12 PM   #13
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I haven't read the article so I'll reserve judgment on it's content, but will offer up that it may be easier to "piece meal" the suspension stuff out ie an article on tires, an article on alignment, sway bars etc.

Even individually these are no doubt daunting subjects, w/ entire volumes written, but you would be able to provide more detailed info (the how and the why- and just importantly the why not )

I'm guessing you could get all kinds of help from folks here- I think we would all like to see a good and successful suby magazine
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Old 11-05-2006, 10:23 PM   #14
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At the end of the day, our hope is that someone might forgo the MBC or a turbo timer and consider instead, an ALK or sway bars. If this happens, we have done our job. Granted, we may never know, like the proverbial tree in the forest, but maybe a bell will ring or something and we can rest knowing that some ricer, somewhere, has some really big sway bars, instead of neon or something atocious like that ( i have been around and seen it all, even on an STI). There will be more tech heavy stuff, we promise. Especially since the LGT needs some love in the suspension dept. It has lots of cool gear but it needs a little tweaking. As we dial in our cars we will tell you how to do so as well.

Incidentally, the Zero to Hero car is a handling MONSTER. It may not have all the power in the world, but it coners like none-other. It may just be the best handling car (other than a lotus 7) that I have ever driven. We will keep you posted. BTW, how did you all like the shoot-out piece? We have some video on that too, stay tuned.
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Old 11-06-2006, 12:55 AM   #15
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Mean,

Your goal of the piece was definitely noble, and I look forward to seeing tech-heavy suspension articles.

The shootout was a pretty fun article. I like the mix of cars, from all modified suspension and (relatively) no power to all aftermarket power and no suspension, plus an all stock ringer to an all stock boulevard cruiser. I would've added a track map and put the type of tire and tire size in the specifications block.

To really bring it to the next level, check out some of what Grassroots Motorsports does with their testing. They had a test with three Evos of varying modification levels. They broke down the track map and pointed out where each car was fast and where each car lost time. When they get together with the Tire Rack for some of their tests, they'll have multiple drivers in each car and give out both fastest laps and average lap times.
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Old 11-06-2006, 05:31 PM   #16
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i agree with Flyboymike, with the arcticle could have had better exicution, but was meant in all good intentions.



Just curious who wrote it?


Also when will we be seeing a V2.0 that is more in depth?
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Old 11-08-2006, 02:59 PM   #17
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I appreciate where some of these guys are coming from. But I also know that like you say a big part of your intended audiance has never thought about or has been too scared to touch their suspension. I think for a first primer it wasn't bad. I do think you should go more in depth, but I think maybe as it's own issue, or suplement. with set-ups for all kinds or drivers and rides, from autocross suggestions, to set-ups for the fools that think going straight is the only way. Address all aspects all the way down to alignment suggestions for tire size and ride height.

As far as the shoot out I too think would have been nice to get a better picture of where each excelled or fell behind.
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Old 11-08-2006, 04:14 PM   #18
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Quote:
Originally Posted by MeanEditor View Post
I see where you all are coming from, however, you guys are coming from a place where you know the deficiencies/flaws of the suspension. I appreciate all your input and it will probably make it's way into a future issue where we go more in-depth. The point is still that for most owners, and after working sales at a few Subaru performance companies i can attest to this, most enthusiasts think power and not balance, handling etc. This is merely a starting point, a way to get people thinking about suspension and we do address that in the article.

We fully expected some flak on this one, suspension tuning is about as dark and archaic a topic as it gets so when we decided to do a "guide" we figured all the "gurus" would either say "nice basic guide" or, "you guys suck."

Keep it coming, and we will take it all into consideration when we go to the next level.
I haven't read the article either...need to go pick up the new copy.

Anyway, I'm enthused to hear that someone has decided to try and educate the general public on suspension and handling. Its too common for people to shoot for maximum power and never think about new brakes to slow it down or a better suspension to actually get some use out of it.

I really like the ideas stated above. To keep it simple and get their attention, point out and address the large issues with the subaru suspension and its handling tendencies. If you want them to read you need to tell them there is a problem. If they hear there is something wrong they will want to know how to fix it. Then in progressive articles you can cover little bits of the suspension on closer detail and discuss how they can change your car's ride and handling and why that is good or bad.

I suppose that's enough for now. I'll have to stop by the subaru dealership and pick up a copy of the magazine and read before I post more comments.
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Old 11-12-2006, 02:05 AM   #19
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It looks like a shopping list to me. No primer at all. "Here's the bits, the prices... now go fix it".

20 years ago we had half the parts ~ but twice the need. Intercoolers we had to source from race houses... Coil overs? Design them from scratch for rebound and compression.

This was simply a lot of pretty 'postage stamp' pictures of products, and was absolutely no help for anyone trying to correct limitations in our suspensions ~

Sad. But true...
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Old 11-12-2006, 11:01 PM   #20
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Default way wrong

Here's another point you guys completely botched. In the article, you state that hollow sway bars are better because they act like a thicker solid bar. This is totally wrong. A hollow sway bar is more flexible than a solid bar of the same diameter. The reason that hollow bars are better is that for a given weight, a hollow bar can be made much larger and have much greater stiffness. Or, a hollow bar can have the same stiffness as a solid bar and have a larger diameter and lower weight.

P.S. I still like the mag anyway but I'd like to see more in depth articles on feature vehicles and tuners/shops.

Stuart
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Old 11-13-2006, 11:36 AM   #21
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Try this little test. Take a solid bar that is say ten feet long, suspend it by both ends with a weight in the center. The bar will bend. Add more weight and it will bend more. Now take hollow tube and do the same thing. It won't bend. Hollow tubing is much more ridgid than solid bar. So if we have two sway bars, one hollow and one solid, the hollow bar will be stiffer than the solid one since it does not flex/bend as readily as the solid one.
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Old 11-13-2006, 02:16 PM   #22
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Try this little test. Take a solid bar that is say ten feet long, suspend it by both ends with a weight in the center. The bar will bend. Add more weight and it will bend more. Now take hollow tube and do the same thing. It won't bend.
If the outer diameter of the hollow tube is the same as the solid bar, then it will bend more than the solid bar.

If you think otherwise, I am sorry but you are just completely wrong and I don't know what else to say to you.
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Old 11-13-2006, 02:40 PM   #23
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That a is totally wrong "assumption"- the solid bar will be stiffer given the same diameter. That's the reason hollow bars are larger in diameter than their solid counterparts (a 25mm hollow bar is roughly equivilant to a 22mm solid bar)- they DO bring weight savings to the table and that's why people manufacture them and some people buy them.
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Old 11-13-2006, 03:42 PM   #24
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Here's a quick ref. for you, MeanE:
http://www.engineeringtoolbox.com/to...fts-d_947.html

Following your logic, if it was possible to remove material from a bar and make it stronger, then where would the limit be? Theoretically, we could keep removing more material making the walls of the tube thinner and thinner, and the bar would get stronger and stronger. Obviously, this is not true. The bar would not keep getting stronger and stronger but would fail.

This is the same basic theory behind Cannondale bicycles having such big aluminum tubes.

Stuart



Quote:
Originally Posted by MeanEditor View Post
Try this little test. Take a solid bar that is say ten feet long, suspend it by both ends with a weight in the center. The bar will bend. Add more weight and it will bend more. Now take hollow tube and do the same thing. It won't bend. Hollow tubing is much more ridgid than solid bar. So if we have two sway bars, one hollow and one solid, the hollow bar will be stiffer than the solid one since it does not flex/bend as readily as the solid one.
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Old 11-13-2006, 05:18 PM   #25
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The equation for a anti-roll bar is fairly simple:

500,000 x ((D1^4)(D2^4)
K = ----------------------------------------------- = 233 lb/in
((0.4244 x LA^2 x CS) + (0.2264 x LA^3))


D1 = outside diameter
D2 = inside diameter (zero if solid)
LA = lever arm
CS = center section length


If you happen to own a 1972 Fiat 128 Sedan with the 22mm solid 128 Wagon front bar, it looks like this:


500,000 x 0.984^4
K = ----------------------------------------------------- = 233 lb/in
      ((0.4244 x 11.25^2 x 31.5) + (0.2264 x 11.25^3))


There is also a modifed version of this formula for lever arms connecting at a less than 90-degree angle to the center section of the bar.

The benefit of a hollow bar is that you lose a great deal of the weight out of the center "hollow" section, but only lose a relatively small amount of cross sectional area. A perfect Subaru example is the so-called "32mm Strano bar" manufactured by Addco, in comparison to the big Whiteline adjustable 27-29mm bar.

The Strano is a 31.75mm bar with a 1/4" wall thickness. It has about the same rate as a solid 29mm bar (assuming all the other parameters remain the same) yet weighs a couple pounds less.

There are numerous other issues that have cropped up in this exact comparison of bars, but I digress

CN: The basic principle of hollow bars is that they can weigh less than a solid bar, given the same effective rate.

Chris H.

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My free STUFF subscription lasts until December 2006! jmonusko Off-Topic 7 08-12-2003 11:33 PM
('93-'01) R&T WRX Guide from Subaru of America asusimpreza Impreza Forum 19 07-19-2001 02:37 AM


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