Jump to content
SAU Community

Recommended Posts

hey,

i bought myself some used lowered front suspension, off a half cut: unknown lowered springs and KYB shocks.

When i had it put on my car, i just went to a average mechanic, seemed he didnt know alot about sports cars.

Anyways when we got the supsension all put on, he was worried about the safety of it all. Because while jacked up in the air, and with the shocks hanging down, the springs just sat about half way up them, so there was a gap (if ya get what i mean, between the top of the springs and the top strut bit).

As he didnt work with sports cars, he said on normal everyday cars, that shouldnt be the case, he said that the springs should always have contact with the struts when they are fully extended.

I am really happy with the hight, makes my front bar exactly 100mm from the ground. So i was wondering if there were any safety probs with this? Maybe if i went over a big hump or something, is there a safety prob with maybe the springs not sitting right on landing?

cheers for any help or advice you can give me :(

STL

Hi Sky, springs should at all times be incontact with the seats, firstly it is illegal for them not to be. Secondly whenever you jack the car up the springs may fall off the spring seat, when you let it down they may not line up. This means you can have the spring hanging out, hit the tyre, rip it to pieces or bind the steering. It is a pretty slim chance that you would have a bump large enough to bounce the car up far enough and for long enough for the springs to jump out, but I have seen it happen.

This is one reason why progressive springs are used, so you can have the car low enough because the soft initial rate compresses easily with the weight. Then the harder rate actually does the work of absorbing suspension movements.

I strongly suggest you have a read here

www.whiteline.com.au

There are some interesting articles on Skyline suspension, heights and spring rates. They have agents in WA.

Hope that helps

Are they just standard springs that have been cut down? If so you will bottom out, hit the bump stops and bounce off the road. If you happen to run into someone else you will be in deep shit as the accident investigation units are not fools and will discover this in no time.

Your insurance won't cover you and the cops will throw the book at you.

Sounds harsh but that's life. :P

thanks for the advice guys.

Yeah, the springs hang from the top seats by about 10cm when the car is jacked up.

Darn, looks like i'll need to go search for some springs :P

Red: nah these aren't cut down standard springs. They are unknown blue coloured ones that came with KYB shocks. They seem very hard compared to the standards. All i know is that was how the package was when they came off a half cut from jap land.

Also on the subject of lowering suspension on a car, i take it i need to have my wheels re-alined?? From what i can tell the camber has changed

thanks again,

STL

thanks for the advice guys.

Yeah, the springs hang from the top seats by about 10cm when the car is jacked up.

STL

I hope you mean 10mm (about 1/2") - 10cm is around 4"

WARNING - thread hijack!!!!

Gary is there any suspension info you don't know?

Seriously though, I have been in touch with several uni's down here to do a Masters degree in automotive engineering design and management (since I already have a number of management subjects under the belt). I feel a need to do more automotive study, but don't want to do the undergad SAE degree, for obvious reasons.

No-one offers even an SAE automotive masters. What would you suggest? My key interests are suspension design, engine management, emmissions, and ultimately performance and motorsport. I have searched a few TAFE campuses but am still at a loss. Where do you get training and experience in these areas?

blind_elk: unfortunately i do mean 10cm! :O That's how far they sit below the top seats when the car is up

After doing some reasearch and more driving, i have to get it fixed asap because the springs are also way too hard, they cause the car to jump around on uneven bumps, makes the car feel unsafe compared to the stokies

Does anyone know if changing to progresive springs will be an answer to my problem?? Any Reconmendations?

thanks,

cheers

STL

From what I know progressive springs are the go. The springs work two ways if you will. The softer part will soak up "sharp edge" bumps. That is, typical road bumps, small holes etc. The firmer part looks after handling charactersitics.

Do some research, there are a few aussie companies that make springs for the 33.

Good luck and keep us posted.

As he didnt work with sports cars, he said on normal everyday cars, that shouldnt be the case, he said that the springs should always have contact with the struts when they are fully extended.

why would a "sports cars" suspension be any different to a normal cars suspension... in this way......

I cant believe he let you drive away with it like this...

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

    • They care about emissions, and cost the most. Save weight where possible, and make manufacturing easier. Less material also let's the engine transfer heat to water quicker, and bring the engine up to temp quicker, better for emissions and getting them past their warranty period.
    • I was under the impression the reason why OEMs are going with solutions like relatively thin "right-sized" cylinder walls with technologies like PTWA and open deck is because they care a lot about whatever marginal knock margin benefits they get from that vs the structural rigidity benefits of a closed deck block and thicker cylinder walls. I also see some weird stuff like plastic inserts in the water jacket around the cylinders to try and equalize cylinder wall temperatures. re: the PRP blocks and heads at the end of the day it's hard to know what is and isn't going to work there, just have to see what the initial buyers say about it.
    • Which is why I didn't mention that hardness testing, and specifically mentioned the bore and deck thickness testing. Yeah, not really. The bore temperature will be a lot more even around the top half inch or so, where the material distribution is dominated by the deck, and which is the only place where the bore surface temperature heating any gas in the cylinder is likely to have any effect on detonation. Think about it. Another inch or so down the bore, you might have a hotter spot. The gas there might get a bit hotter, then the piston rises squeezes that gas away from there at high speed and mixes it with other gas from nearby. Instant dilution of the problem. I'd be surprised if it was an issue at any time other than in racing engines or OEM dev engines being run at the ragged edge of tuning. Say what now?
    • https://dsportmag.com/the-tech/education/engine-tech-material-hardness-testing/ The PRP testing on block hardness I'm not sure how much it actually can be trusted. The thinner cylinder walls on RBs is a bit of a problem vs 2JZ but it really depends on the design goal. Siamesed cylinder bores like a 2JZ cause uneven cylinder wall temps too, which means a bit of distortion induced by that + the hotspot can affect knock margin. Something that actually gives me a bit of pause with the PRP block, whether super thick cylinder walls are going to keep it from being drop-in compatible on an otherwise OEM rebuild. 
    • Yeah very valid point. I am waiting for one of the other tuners to come back from vacation so he can help me a bit when the cat is installed again. In the meantime I am going to finish up my polishing and ceramic coating that I have started myself.    N45 Dr Beasley product is highly recommended for a paint primer / polisher. Using this EXO Gtechniq also for the ceramic but next time might use the light serum before hand also. Looks great. 
×
×
  • Create New...