R32 Top Secret Rear Diffuser

[Sleepergm]

Hi all,

 

Anyone running this rear diffuser? Was just curious can I just install the center diffuser without the side fins or do the side fins act as supports to the whole piece? 
 

just in Hong Kong and the police will pull me over running the side fins I suspect. 
 

photo attached. 
 

thanks 

[GTSBoy]

The side bits just dangle in the breeze. They don't do anything. Neither does the rest of it, without a flat floor and some time spent testing to find out how low you need to make the car to gain any effect.

[Sleepergm]

On 19/03/2024 at 6:16 AM, GTSBoy said:

The side bits just dangle in the breeze. They don't do anything. Neither does the rest of it, without a flat floor and some time spent testing to find out how low you need to make the car to gain any effect.

so essentially I dont need to add the sides and can just add the back section if I wanted? 

Need to add the additional lip on the front of the car on top of the top secret lip and also the back to make the car look lower ... the car sits super high right now ... I have coil overs and will continue to lower them but worry about rubbing. If i want to also tuck the tires in what route do I have to go - charge control arms or does everyone just roll the fenders? I mean I just worry I will crack the paint with rolling as its original paint now. 

 

Thanks

[Duncan]

The rear wheel/guard position is a whole topic on its own.

Do you know what size and offset wheels you have?

In general, if you lower the ride height you gain camber which tucks the top of your tyres inside the guard. Depending on tyre width (careful) guard rolling is very commonly required.

It is much  more common to need to add adjustable bushes to reduce, not increase, the camber once the car is lowered a little.

[Sleepergm]

22 hours ago, Duncan said:

The rear wheel/guard position is a whole topic on its own.

Do you know what size and offset wheels you have?

In general, if you lower the ride height you gain camber which tucks the top of your tyres inside the guard. Depending on tyre width (careful) guard rolling is very commonly required.

It is much  more common to need to add adjustable bushes to reduce, not increase, the camber once the car is lowered a little.

Running 10J x 18 et25 bbs lm. With potenza sport 18 x 265/35 … photo before I dropped the height more. 
 

can we roll the fenders without damaging the paint u think? 
 

Shop eas talking about adjusting the camber with new arms… 

[GTSBoy]

Measure the vertical distance from wheel centre to guard.

If it is <345-350mm, do not consider going any lower. Should not be any lower than that, otherwise the LCAs will be at the wrong angle and you'll not have good handling. Although I'm guessing that in HK looks are more important than performance anyway.

As Duncan already said, when you lower the car you gain -ve camber anyway, which tucks the tops in more. But....as he also said, adjustable arms are usually used to wind some of that extra -ve camber back out, not increase -ve.

[Sleepergm]

23 hours ago, GTSBoy said:

Measure the vertical distance from wheel centre to guard.

If it is <345-350mm, do not consider going any lower. Should not be any lower than that, otherwise the LCAs will be at the wrong angle and you'll not have good handling. Although I'm guessing that in HK looks are more important than performance anyway.

As Duncan already said, when you lower the car you gain -ve camber anyway, which tucks the tops in more. But....as he also said, adjustable arms are usually used to wind some of that extra -ve camber back out, not increase -ve.

This is interesting … I will go and measure. I see everyone running alot lower to be honest with u. Yeah I really like a good seamless look but I like performance also. My car will be running around 550hp … and it handles amazing right now

[Sleepergm]

On 21/3/2024 at 9:17 AM, GTSBoy said:

Measure the vertical distance from wheel centre to guard.

If it is <345-350mm, do not consider going any lower. Should not be any lower than that, otherwise the LCAs will be at the wrong angle and you'll not have good handling. Although I'm guessing that in HK looks are more important than performance anyway.

As Duncan already said, when you lower the car you gain -ve camber anyway, which tucks the tops in more. But....as he also said, adjustable arms are usually used to wind some of that extra -ve camber back out, not increase -ve.

This is interesting … I will go and measure. I see everyone running alot lower to be honest with u. Yeah I really like a good seamless look but I like performance also. My car will be running around 550hp … and it handles amazing right now

[Sleepergm]

Also just checked I’m at 36cm on the back from middle rim to fender. So I guess 2cm more drop with the coilovers. That’s kind of what I was going to do anyway to be honest. 

[GTSBoy]

Well, maybe 10mm.

[morboost]

don't roll the fenders, I have been in this position before and had to make a choice between rolling the fenders or adding camber to fit wheels that didn't quite fit I thought about it for a while and added camber. The wheels are now gone I have better fitting wheels and i'm grateful I didn't mess up the body work. Even if you don't crack the paint a rolled lip on the rear guards is a prime spot for water, debris, dirt, leaves to get stuck and rust.

[Sleepergm]

15 hours ago, morboost said:

don't roll the fenders, I have been in this position before and had to make a choice between rolling the fenders or adding camber to fit wheels that didn't quite fit I thought about it for a while and added camber. The wheels are now gone I have better fitting wheels and i'm grateful I didn't mess up the body work. Even if you don't crack the paint a rolled lip on the rear guards is a prime spot for water, debris, dirt, leaves to get stuck and rust.

Awesome thanks. How u adjust the camber? What kit or tie arms did u buy to adjust it? 
 

thanks 

[morboost]

I used adjustment bushes in the factory arms, this is the superpro part number: SPF1869K for your application this kit goes in your rear upper control arms and traction rod arms its important to move the camber arm and castor arm the same distance in the rear to avoid axle tramp you will get +/- 1 degree camber adjustment plus the factory adjustment bolt for fine tuning. For the front use part number: SPF1659K for camber and use part number: SPF1202AK for front caster. Once these bushes are fitted everything looks oem, if you don't care about that and plan to track your car you might be better off to change to adjustable arms as fitting the bushes is time consuming but road legal in Australia.

 

 

[GTSBoy]

Adjustable length arms are legal in Oz. It's just spherical joints that are not legal (unless engineered). It is a pure myth that adjustable arms are an instant defect.

I have adjustable arms all over my daily driven 10000km/yr car. And some of them even have (very sneaky) spherical joints in them.

FWIW, for an R32, the ONLY way to have adjustable camber worth a damn in the front, is to use the GKTech FUCAs. They are a complete pain in the arse to work with on a streeter, but they are the only ones that don't bend or break and yet still do all the things that they absolutely have to do. Every other FUCA option on the R32 is a waste of time. I have used adjustable poly bushes in stock arms. They flog out badly. I have used the I shaped one from (I can't remember where right now, but have posted extensively on the topic so you could search if you cared) and they flog out and bend at the spot where they pivot in the centre. The pivoting in the centre is the feature that led me to try them, as the rigid stock style and almost every other aftermarket arm loads up the bushings massively (causing the flogging out) because the Nissan boys did not sort out the kinematics of the arms properly. This is why they changed completely for the R33&4.

On the rear, adjustable length uppers and traction rods. Then you have to make yourself a bump steer gauge so you can adjust the traction rod length to give the smallest amount of bump steer. You can't just guess and and you can't just guess when you use adjustable poly bushes there either (although there is far less possibility of f**king it up with poly bushes because they don't offer 3/10th of f**k all adjustment).

[Sleepergm]

Thanks for the info. I think the adjustable control arms are the way to go then. If lowering my car another 10mm to 15mm doesn’t cover it. I am wary also that I might rub at this height? Haven’t had any issues at the current height as I have flocked her on some heavy corners. 

[morboost]

no problems, arms are easier. When you measure how much room you need remember that 1 degree of camber gives about 10mm clearance and add some more room if you still have hicas.