Jump to content
SAU Community

Recommended Posts

Just saw an article on Whiteline's kit for the Dugong ie latest model WRX, including fairly straightforward underbody chassis bracing. Despite the fact that there's probably a good market, I suspect it will be quite some time before they produce similar for Skylines, if ever, unless Sydneykid can convince them otherwise.

The R32 GTR could do with a bit of stiffening and most of us are using front and rear strut braces. The only other thing I've seen around is the Do Luck brace that goes across the tunnel and bolts to the inner sills but I'm not sure it does much. Of course a cage would do the trick but it's illegal for road use. The R33 GTR has a big panel between the rear shock towers that seems to keep both of them moving in the same direction quite well, and the R34 GTR improves on this again.

There is a lot of stuff in Japan - various brackets etc but I'm not sure of their effectiveness. Last thing I want to do is add 10 kg of weight for no improvement in rigidity.

Has anyone got experience with Japanese stuff or their own, that actually works?

Cheers

Edited by Scooby
Link to comment
https://www.sau.com.au/forums/topic/211975-chassis-bracing-components/
Share on other sites

Kansai service centre sell a whole packaged of underbody braces/brackets for the R32 GTR. I have no idea if they work or not though.

http://www.hkskansai.co.jp/html/parts/roa/roa.htm

Unlike the Wrecks, Skylines have good suspension pick up point rigidity, which should not be confused with general chassis rigidity. Obviously in the areas of general chassis rigidity R33's are an improvement over R32's and R34's are even more rigid. What is perhaps not so obvious is that series within those model changes have chassis rigidity improvements. Mostly as a result of mandated improvements in occupant safety. Hence an R32 S2 (post 1990) is more rigid than an R32 S1 (1989/90).

I can say without exception that I have yet to see any bracing that I would consider worthwhile. Simply put, they all fail the triangulation test.

Cheers

Gary

I've got a Nismo (at least I thought it was Nismo) full underbody brace kit installed on my R32 GTR... freakin' solid and massive amounts of "feeling" through the wheel with exactly what the car is doing...

I know I am asking a lot here...but any chance you could post up a pic of the one you got fitted ??...

Unlike the Wrecks, Skylines have good suspension pick up point rigidity, which should not be confused with general chassis rigidity. Obviously in the areas of general chassis rigidity R33's are an improvement over R32's and R34's are even more rigid. What is perhaps not so obvious is that series within those model changes have chassis rigidity improvements. Mostly as a result of mandated improvements in occupant safety. Hence an R32 S2 (post 1990) is more rigid than an R32 S1 (1989/90).

I can say without exception that I have yet to see any bracing that I would consider worthwhile. Simply put, they all fail the triangulation test.

Cheers

Gary

Hi Gary

so...you're going to start making the good stuff for us? :D or are there reasons why it's simply not production feasible? also is it feasible at all or are there fitment / design issues that make it impractical to pursue rigidity improvements unless it's a full cage ?

Cheers

Edited by Scooby
I've got a Nismo (at least I thought it was Nismo) full underbody brace kit installed on my R32 GTR... freakin' solid and massive amounts of "feeling" through the wheel with exactly what the car is doing...

I am not a big fan of seat of the pants judgement, the placebo effect is strong in car modifications. In a pure technical sense I have yet to see a value for money result as far as improving torsional rigidity goes. The testing is actually quite simple, a basic home garage test of rigidity. Stick the car on 4 stands, under the sills is OK. Then jack one corner of the car up 100 mm and see how much the other corners move. I do that 4 times, once for each corner. Now bolt on any number of underfloor, in cabin, under bonnet and in boot braces. Then repeat the test. Note any differences. An example, my own R32GTST before and after the 6 point roll cage fitment across the chassis.

LHR 100 mm - RHR 87 mm before, 93 mm after

RHR 100 mm - LHR 86 mm before, 92 mm after

LHF 100 mm - RHF 91 mm before, 95 mm after

RHF 100 mm - RHF 90 mm before, 94 mm after

That's obviously the across, you can also do along, put the jack in the middle, again under the sill and measure;

Centre LH 100 mm - LHF 90 mm before, 95 mm after

Centre RH 100 mm - RHF 91 mm before, 96 mm after

Centre LH 100 mm - LHR 90 mm before, 94 mm after

Centre RH 100 mm - RHR 91 mm before, 97 mm after

This is not an absolute test as the chassis walks on the stands, it is a comparison test only. So when you do it yourself don't get hung up on the numbers themselves, the difference (improvement) is all that matters.

The other test is corner weights, how many mm of adjustment of the spring seat on one corner alters how much weight on that corner. A soft (flexible) chassis means more turns to achieve the same weight transfer as a rigid (inflexible) chassis. That is a more reliable real world test as it is the wheels that move up and down and that is what is passed though the chassis. That's how we tell when a V8Supercar chassis is due for replacement, it gets lazy in its response to changes, hence why a new chassis is built each season. Usually around Bathurst time as long distance events show up any lack of rigidity.

Cheers

Gary

Unlike the Wrecks, Skylines have good suspension pick up point rigidity, which should not be confused with general chassis rigidity. Obviously in the areas of general chassis rigidity R33's are an improvement over R32's and R34's are even more rigid. What is perhaps not so obvious is that series within those model changes have chassis rigidity improvements. Mostly as a result of mandated improvements in occupant safety. Hence an R32 S2 (post 1990) is more rigid than an R32 S1 (1989/90).

I can say without exception that I have yet to see any bracing that I would consider worthwhile. Simply put, they all fail the triangulation test.

Cheers

Gary

I would have to argue that... true that it is ideal to have a 3 point brace for that brace to be as rigid as possible however you are not after multi directional rigidity in a lot of situations. For instance the plain old strut brace works wonders and is a 2 point brace (in most cases anyway). It works fine because its job is to tie 2 points together and stop the distances between those two points getting greater or smaller hence preventing suspension geometry change through chassis flex...

same would apply underneath the car for chassis flex as I would imagine that when the car goes over a ripple strip or just leans hard under heavy cornering on one side that the chassis would have a tendency to flex in the middle. By tying the 2 chassis rails together with a brace (or 3) you would help prevent this flex...

I would have to argue that... true that it is ideal to have a 3 point brace for that brace to be as rigid as possible however you are not after multi directional rigidity in a lot of situations. For instance the plain old strut brace works wonders and is a 2 point brace (in most cases anyway). It works fine because its job is to tie 2 points together and stop the distances between those two points getting greater or smaller hence preventing suspension geometry change through chassis flex...

same would apply underneath the car for chassis flex as I would imagine that when the car goes over a ripple strip or just leans hard under heavy cornering on one side that the chassis would have a tendency to flex in the middle. By tying the 2 chassis rails together with a brace (or 3) you would help prevent this flex...

Not really. the car can still twist the same as ever.

Front strut braces are ok as it ties a point thats close to the inner upper control arm to another point close to the inner of the other upper control arm. so yes, they are good at effectively boxing that section of the car and yes, it improves it. The same can be said for the rear to a lesser extent, as the upper contol arm mounts to the subframe so bracing the strut tops has less effect. The load of the rear struts is almost all vertical, only minimal horizontal. They don't move towards each other or away from each other to any great extent anyway, the main concern is the vertical loading. Whats bracing against that if you have a strut brace running horizontally?

And again, whats stopping the front end of the car twisting one way while the back twists the other? It's effectively a torsional force so bracing two rails together to form a ladder is doing 2/5ths of f*&k all to brace against it.

And again, whats stopping the front end of the car twisting one way while the back twists the other? It's effectively a torsional force so bracing two rails together to form a ladder is doing 2/5ths of f*&k all to brace against it.

that seems to be the downfall with underbody braces - they don't have anything that braces across the chassis effectively in the direction of the force. i'm not sure how you could achieve that without having height in at least one domension of the brace with the other dimension being across the chassis, such as the panel at the rear of the R33 GTR. the underbody stuff would help if the problem was with the front meeting the rear in a horizontal plane, but its not.

pics please paul! I need ideas for how to get the cage to the strut towers while still keeping the booster

bit hard to get a decent pic...but these will give you an idea.

NOTE...these are nothing like the AutoSelect ones...the jap ones are much beefier with cross bracing as well. But display's the general idea.

post-23582-1206611835_thumb.jpg

Would pop riveting inside the engine bay to the door sills be any good? i know disadvantage is the little extra weight of the rivets. Thats how my car came from japan and it also have similar to what dirtgarage but does extend as far, by AS.

Probably getting more spot welds would be better than riveting.

post-24749-1206617030_thumb.jpg

post-24749-1206617078_thumb.jpg

bit hard to get a decent pic...but these will give you an idea.

NOTE...these are nothing like the AutoSelect ones...the jap ones are much beefier with cross bracing as well. But display's the general idea.

I have seen that bracket used as the mount for the front on board jacking system.

Cheers

Gary

Would pop riveting inside the engine bay to the door sills be any good? i know disadvantage is the little extra weight of the rivets. Thats how my car came from japan and it also have similar to what dirtgarage but does extend as far, by AS.

Probably getting more spot welds would be better than riveting.

Rivets work loose, not a good idea. Extra spot welds or stitch MIG/TIG welding is a far superior solution.

Cheers

Gary

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Update 3: Hi all It's been a while. Quite a lot of things happened in the meantime, among other things the car is (almost) back together and ready to be started again. Things that I fixed or changed: Full turbo removal, fitting back the OEM turbo oil hardlines. Had to do quite a bit of research and parts shopping to get every last piece that I need and make it work with the GT2860 turbos, but it does work and is not hard to do. Proves that the previous owner(s) just did not want to. While I was there I set the preload for the wastegates to 0,9bar to hopefully make it easier for the tuner to hit the 370hp I need for the legal inspections that will follow later on. Boost can always go up if necessary. Fitted a AN10 line from the catch can to the intake hose to make the catchcan and hopefully the cam covers a slight vacuum to have less restrictive oil returns from the head and not have mud build up as harshly in the lines and catch can. Removed the entire front interior just shy of the dashboard itself to clean up some of the absolutely horrendous wiring, (hopefully) fix the bumpy tacho and put in LED bulbs while I was there. Also put in bulbs where there was none before, like the airbag one. I also used that chance to remove the LED rpm gauge on the steering column, which was also wired in absolute horror show fashion. Moved the 4in1 Prosport gauge from sitting in front of the OEM oil pressure gauge to the center console vents, I used a 3D printed vent piece to hold that gauge there. The HKB steering wheel boss was likely on incorrectly as I sometimes noticed the indicator reset being uneven for left vs. right. In the meantime also installed an airbag delete resistor, as one should. Installed Cube Speed premium short shifter. Feels pretty nice, hope it'll work great too when I actually get to drive. Also put on a fancy Dragon Ball shift knob, cause why not. My buddy was kind enough to weld the rust hole in the back, it was basically rusted through in the lowermost corner of the passenger side trunk area where the wheel arch, trunk panel and rear quarter all meet. Obviously there is still a lot of crustiness in various areas but as long as it's not rusted out I'll just treat and isolate the corrosion and pretend it's not there. Also had to put down a new ground wire for the rear subframe as the original one was BARELY there. Probably a bit controversial depending on who you ask about this... but I ended up just covering the crack in the side of the engine block, the one above the oil feed, with JB Weld. I used a generous amount and roughed up the whole area with a Dremel before, so I hope this will hold the coolant where it should be for the foreseeable future. Did a cam cover gasket job as the half moons were a bit leaky, and there too one could see the people who worked on this car before me were absolute tools. The same half moons were probably used like 3 times without even cleaning the old RTV off. Dremeled out the inside of the flange where the turbine housing mates onto the exhaust manifolds so the diameter matches, as the OEM exhaust manifolds are even narrower than the turbine housings as we all know. Even if this doesn't do much, I had them out anyways, so can't harm. Ideally one would port-match both the turbo and the manifold to the gasket size but I really didn't feel up to disassembling the turbine housings. Wrapped turbo outlet dumps in heat wrap band. Will do the frontpipe again as well as now the oil leak which promted me to tear apart half the engine in the first place is hopefully fixed. Fitted an ATI super damper to get rid of the worn old harmonic balancer. Surely one of the easiest and most worth to do mods. But torquing that ARP bolt to spec was a bitch without being able to lock the flywheel. Did some minor adjustments in the ECU tables to change some things I didn't like, like the launch control that was ALWAYS active. Treated rusty spots and surface corrosion on places I could get to and on many spots under the car, not pretty or ideal but good enough for now. Removed the N1 rear spats and the carbon surrounding for the tailpipe to put them back on with new adhesive as the old one was lifting in many spots, not pretty. Took out the passenger rear lamp housing... what do you know. Amateur work screwed me again here as they were glued in hard and removing it took a lot of force, so I broke one of the housing bolts off. And when removing the adhesive from the chassis the paint came right off too. Thankfully all the damaged area won't be visible later, but whoever did the very limited bodywork on this car needs to have their limbs chopped off piece by piece.   Quite a list if I do say so myself, but a lot of time was spent just discovering new shit that is wrong with the car and finding a solution or parts to fix it. My last problem that I now have the headache of dealing with is that the exhaust studs on the turbo outlets are M10x1.25 threaded, but the previous owner already put on regular M10 nuts so the threads are... weird. I only found this out the hard way. So now I will just try if I can in any way fit the front pipe regardless, if not I'll have to redo the studs with the turbos installed. Lesson learned for the future: Redo ALL studs you put your hands on, especially if they are old and the previous owners were inept maniacs. Thanks for reading if you did, will update when the engine runs again. Hope nothing breaks or leaks and I can do a test drive.
    • No those pads are DBA too  but they have colors too. I look at the and imo the green "street" are the best.
    • I’m not sure what happened I told them about sonic tunes free OTS tune and the next the I know .. I was booted..   To funny 
    • Yea - I mean I've seen my fuel pump which is decades old and uh, while I'm not saying this with real knowledge... but I sure get the ick at using anything in the fuel system that produced the state of that pump. Many years ago I went through multiple pumps (and strainers) before I dropped the tank to clean it out with extreme violence. I'm talking the car would do maybe 50km before coming to a halt, which resulted in me cleaning out the filter with some brake cleaner and going on my way. None of my stuff ever looked like what came out of your fuel tank. I don't think I'd be happy with it unless every single component was replaced (or at least checked/cleaned/confirmed to be clean here).
    • I'm not going to recommend an EBC pad. I don't like them. Just about anything else would suit me better. I've been using Intima pads for a while now.
×
×
  • Create New...