Corksil

Hey I am working on a build and I cannot find (2) parts i'm looking for.

One is a side-frame bay-brace which hides under the carbon fiber fenders and makes up for the loss in rigidity. They look like this...



The other is an H-type brace that goes under the chassis. It ties the front LCA to points back behind the jack-lift-points. Something like this...

https://honda-tech.com/attachment.ph...1&d=1265307931

thanks! (mods plz don't move this to WTB marketplace - i think my question is more tech than WTB)

v4lu3s

pretty sure tanabe makes an h brace that goes under the car. and i think the one you posted a pic of is made by megan racing.
never seen the other braces. i was always told the front fenders were skin only and not structural

dh

iTrader: (3)

Megan Racing makes some of those fender braces:



J's racing also makes them. I believe they're pretty rare though.

Corksil

correct. the front fenders aren't really structural. But if there are gains to be had, i want them.

thanks man, i will look into costs etc tomorrow morning.

Do these braces actually improve handling? Anyone care to chime in (who owns them)

thanks HT

ESP.net

Bolt in ones are koo but it is best to make your own and weld them in. $10 in steel. Using door hinge bolts has been talked over and over, sucks when jacking and door wont sit like it did before... plus welding is much more solid = more function.

Corksil

not to disagree but are you speaking from personal experience?

in that picture up there you can see that the brace appears to bolt on OVER the hinges (assuming you get longer bolts to hold it all on) - so why would the door sit incorrectly? if the brace was over the hinges instead of under, the lines of the car would be unaffected (assuming the fender would fit properly over the brace without contact or mods)

and why would the brace affect jacking? it doesn't look like it even comes close to the factory lift point below the runner..

i agree that welding sounds like a better option. i will be sure to revisit this thread with pics when i have my fenders off and am ready to undertake the custom fab.

thanks for the shouts dude

asianflava

Have you seen this?

http://www.crxcommunity.com/viewtopic.php?f=6&t=6911

Corksil

Not until now no.

I read the entire thread over there and i think i'm gonna have the guy who welds my cage in just weld me some braces directly to the shell..

thanks for the link dude.

DumpdEJ6

Let us know if you notice any significant difference in wheel hop or body rigidity, I'm very curious about these as well. It seems like a pretty cheap mod if you have access to a welder, if its effective then I'll be looking into doing this myself.

Corksil

I am hearing that welding steel stock directly to the shell of the car is far superior to using pre-made brackets and existing bolt-holes.

i recommend you do this.

Read this thread, it's someone asking the exact same question and having the exact same discussion with CRX owners...

http://www.crxcommunity.com/viewtopic.php?f=6&t=6911

gringo7718

This is a good thread >>> https://honda-tech.com/forums/road-racing-autocross-time-attack-19/fender-brace-firewall-brace-experience-updates-2526595/

here are some interesting photos to give you ideas.

http://www.iwsti.com/forums/gd-suspe...lots-pics.html

SSWorks CRX - stitch welds on chassis and bar from firewall to shock tower.


remove undercoating in preparation for stitch welding.




Welded in Gussets to reinforce the shock tower area called "boxing in"


Welded Bars from shock tower to frame rail


full tube chassis with tube to front frame rail


welding entire chassis

zrickety

iTrader: (1)

That's one of the best posts I've seen in awhile ^^
I like the welded seams...I might try that in the future.
I don't see the braces on J's Racing, but somebody should make these!

OneBadTurboCRV

If you like the idea of welded seams you might want to highly consider doing right. You can see in almost every picture that a lot of the "tack" welds aren't even fused properly on both sides. This isn't even close to true "stitch" welding... I am sure it may help a tiny bit, but by the looks of the welds I would assume under and real stress - popcorn anyone? Add all that to uneven spacing (while not crucial) starts to negate the benifit - what it that 3" gap you left WAS the weakest point to begin with?

Another problem I see with the bolt on ones - that area of ALL vehicles sees a lot of stress and is typically under engineered (like most things now days) to handle the constant stress of opening and closing doors. While you could say that adding bracing should help - my retort would be - have you ever jacked up a vehicle from the front lifting point and seen the front end flex up? Or much more noticeable placed jackstands under the "proper" jacking point to watch the front end sag down? This is what the one poster was referring to I believe...

You can do anything - but to do it right is a completely different story.

gringo7718

Only you would find something "wrong" with the engineering of this car.





The only way to prevent the flex you are describing will be to tube frame the entire thing. That being said, big improvements can be made by using all of the discussed techniques together.

-Bolt in fender brace
-stitch welded chassis
-good solid strut bar
-Box in some areas
-Weld in a few misc. bars
-Foam fill the upper fenders & frame rail


As far as the welding technique, I have seen several different techniques and I wonder which is best?

long stitches



vs.

short stitches (I can only assume this is the winner)

OneBadTurboCRV

I call it like I see it - poor welds/craftsmanship is just that - poor work. You don't get an "A" for effort in the real world for trying... If you can't weld Appropiately when someone's life may be on the line, then why take the risk at all? I can assure you that the picture of the red vehicle is most certainly the "winner". The tack welds are not even applied properly on the white car let alone good welds... Even the gussets are tacked in - its just pathetic really. You must understand, I never said the vehicle was not capable from being fast or performing - I am strictly looking at it from a "right or wrong" perspective.

Red car = stitch welding
White car = tack welding

A typical properly tack weld for 1/4" plate is good for around 6,800 lbs shear strength... and can lose a lot of that if it's not "perfect". While a properly applied weld (even in stitching scenarios) wit 7018 can be 70,000 lbs tensile strength... You tell me which is better?

(Just because you see 6,800 for a tack doesn't mean you can't easily rip it apart by hand...)

4drEF

I ran the original A-sports fender braces
(10+ years ago)
As well as Upper and lower front braces

The chassis flexes in so many places (consumer commuter bucket cars that weren't designed for race) that the fender braces alone are worthless.
With the front chassis braced, ES master kit, and then the fender braces were noticeable.
Negligible, but noticeable.
Opening my door with a front wheel off the ground was greatly improved so -yes- they work.
I would NEVER buy them again though.
For the price, welding a solid bar would be more effective and stronger.

gringo7718

Think about it this way.......
Everything on this car was selected to be this way. They didn't go with one product because they got a deal on ebay, but rather because the engineers selected the parts. The car performs well and that is not a mistake. I have to assume that the engineers that helped build the car knew what they were doing, and selected these types of welds for a reason - regardless of wether or not we understand those reasons.

Perhaps they had made a decision to sacrifice rigidity in order to save weight. Or maybe they found that these types of welds are "better" for their setup/environment. In their defense, they are able to make a higher # of stitch weld attachment points for any given length and maybe that offers some advantage.

OneBadTurboCRV

... I guess we will just leave it at that. I have been doing this for over 40 years and have watched many "engineers" come and go... Praise them as you wish - but the facts still remain the same.

K7-1Ktrevor

just because the car preforms doesn't mean it could preform better. he's right about the welds but maybe thats all the strength that the chasis needed. we are talking about a 1600lb car or so here. probably lighter.

gringo7718

Here are a few more pics of fender braces.

Ultra Racing Fender brace (looks like a poor design to me)


and a few others

Corksil

Thanks for postin the pics. It's inspired me and I have reworked my plans with this build. I have decided to purchase a welder and begin practicing. I will be bracing my chassis and reinforcing everything in the same style as done in the pictures you posted. I'll stay away from the bolt-on mod areas, as I would like to use boltons instead for aesthetic appeal. (weld reinforcements everywhere, but still use bolt-on braces.)

it's good to see the pics you posted because it gives me an idea of where and how to reinforce the chassis. I will be looking into this further..

@n3v454+|5f!3d - it's good to read a more technical criticism of the reinforcement-welds. Like I said I plan to do this to my chassis with my own welder. You mentioned how the front of a car sags when lifted @ the jack points. I have witnessed this myself and I'm aware that it is an issue. I agree that using boltons to 'stiffen' the chassis does help - but i also agree that we need a lot more than boltons to achieve the rigidity we need in an ideal scenario.

so what are the options then? weld an entire chassis from scratch out of steel stock and then fit the oem bodypanels over it or something? That would be too heavy. there have to be compromises... what do you recommend for overall chassis stiffening?

I also agree. but what do you mean foam fill the fenders.. What sort of foam and is there anything else i should know..?

@n3v454+|5f!3d - I will be sure to use stitch welds when I reinforce my chassis. I will be sure they are atleast 1/2" long and properly done/prepped etc. The red car looks much stronger to me.

Did you notice that the white car has a bolt-in rollcage hiding up in the wheelwell above the RTA? That in itself doesn't look very safe.

I'm going to reinforce the entire chassis and use boltons etc etc. Thanks for the tip, I will use flat steel stock instead of purchasing expensive parts like these.

Very true - tho I can't help but notice they went with a bolt-in roll cage. That doesn't scream DONT CUT ANY CORNERS to me... I just want to make sure my own car is built right.

I like the second pic you posted of the braces best. Looks like it may be this car and this is the design and style I will be emulating - atleast for the fender braces.



as trevor pointed out these cars are very light to begin with. And they do perform quite well in OEM spec. And theoretically improving them with welding/braces will only increase the performance further. The handling of these particular cars tops that of 95% of all other vehicles on the road - improving them further is almost idiosyncratic.

Thanks HT!

OneBadTurboCRV

Personally, I would just weld all the seams, brace the unibody front and rear, and all crossmembers and shock towers. Take a blend of all the pictures you see and you should have the "ultimate" setup. The best part of a "FF" vehicle (front engine, front wheel drive) is the chassis flex is on one line on a plane for the most part (front to back). On a "FR" vehicle chassis flex can be seen in "3D" as it moves in all directions - front to back and side to side. Obviously a SCAA type vehicle sees flexing in all directions due to the nature of the driving, but most of this is taken care of by the suspension. Any well conceived setup for both straight line, circle, or "crazy" racing can help the vehicle greatly.

Somewhat a negative to all this stiffening is the suspension must be fine tuned to compensate for no/minimal body flex. If you have the same suspension setup across 2 vehicles - the one with a stiffer chassis will grip less. This of course can be easily compensated by a proper suspension. This will involve different spring/shock rates, weight, and ect for each corner to "balance" the vehicle out. If you are serious I highly recomend all this is done with the primary driver in the drivers seat.

That's about as "deep" as I am going to go for now.

gringo7718

Apparently there is a foam that you can mix together, and pour it in the negative spaces of your chassis. It is supposed to be poured in the frame rails and other gaps to improve rigidity.

here is a link about it
http://www.autofoam.com.my/index.php...me/application
ttp://www.subrosa.com.my/automotive_foam.html
http://www.sr20-forum.com/suspension...chassis-6.html

Here is the foam
http://www.junauto.co.jp/products/re.../index.html?en


examples of places to foam chassis

neg space in front fenders, and frame rail which runs length of cabin under car


Front Frame Rails


just more ideas

Corksil

..."weld all the seams, brace the unibody front and rear, and all crossmembers and shock towers. Take a blend of all the pictures you see and you should have the "ultimate" setup.."

consider it done. thanks for your input on this. I will be continuing to study this and I will post any new epiphanies here.

I have read every single link posted in this thread, and just finished reading the foam ones. I have decided that I will foam the chassis, but the extend of it I am unsure. I do not want to create dead/inaccessible areas that I may need access to in the future (fixing rust, installing electronics in between inner/outer subframe shell etc..) - But I plan on foaming most everything I can get away with.

Thanks for the intel to everyone who posted here. I can't wait to get on the plane and go find my CRX in the next few days...

I love HT!

m_shake

Alternative to j's racing
http://www.more-japan.com/nagisa-aut...civic-crx.html