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10cm of up travel ( bump) from your static height. I bet there is less than 15mm of down travel, that would explain things happening on turn in.
You mean that i have perhaps too much up travel and not enough down travel ? I made a little check this evening and i saw that the rubber part under the right rear spring is not properly in place. I will remove it to replace it properly.
I will also remove the rear shocks to measure their total travel. If for example the total travel is 15cm. Should i set it with 7.5cm travel up and 7.5 travel down ?
Concerning the corner balance, i didn't do it. Don't see a place near me where i can measure the weight on each wheel separately.
Concerning the ride height, i found the car faster on the track with lower settings. Terramask and others who race their Z : What is you ride height ? (taken on wheels arches ?)
Car is pretty soft (assuming the rear spring is in the OE Position)...you could be bottoming out the rear shock with 10cm of available travel, especially over bumps.
+1.
Also are you sure that is 10cm usable travel with the wheel and tire on?
Also are you sure that is 10cm usable travel with the wheel and tire on?
So one of you say that perhaps i have not enough down travel, and others that perhaps i hit the bumpstops...
When the car is on its wheels, does the shocks has to be mid course up and down ? Or more up travel than down travel ?
I assume on the track up travel is more important than down travel since there are few bumps on track surface ?
Here is another pic on a very slow and tight corner on Fay de Bretagne track in France : the cars has roll, but don't forget i have massive grip from the 265 and 275 Toyo R888. I will buy Whiteline sway bars with endlinks this month to reduce roll and see what it does to the handling. I'm also considering buying SPL Bushings.
It's been also a long time since i'm considering gutting the car...
If my car wasn't up on jack stands I would measure for you. But my spring bucket arms are very close to parallel to the ground at ride height.
Take your springs out, just have your damper installed, install your tire ( pull a sway bar endlink to make this easier) and pout the jack under your tire and see where the bump stock engages. Mine allows the tire almost up to the wheel in the wheel well. If to stops way short you don't have enough travel , if the tire it touching sheet metal make adjustments. From your ride height you will want droop, I try to set between 25% to 50% of the usable travel in droop.
If you don't have enough droop, as soon as you turn in you are trying to lift the inside tire off the ground and cause cause a loss of traction at speed.
Last thing, what feels better and what gives better lap times is not always the same.
So one of you say that perhaps i have not enough down travel, and others that perhaps i hit the bumpstops...
It could be either or, really just depends on the combination of ride height and shock length.
It sounds like you have the OEM rear spring configuration, in which case keep in mind that shock body length does not affect rear ride height, only piston travel.
I am somewhere between 25in and 26in (closer to 26") ground to fender front and rear IIRC.
I will check what you propose in the comings days/weeks. I will keep you informed.
I have the rear springs at the OE place yes.
I assume there are some coilovers that put springs with the shocks then ? If so are the mount up to the task to have all the load there ? I'm wondering...
A question about SPL bushings : are they usable on the road ? Are they worth their price ? Is so, where should i begin to change my bushings ? Front or Rear ? If front perhaps somewhere specific ?
Most beneficial SPL bushing would be the front LCA inner and compression arm bushing. How long they last on the road, no idea. But I daily drive mine for over 20k miles before my car turned into track only
Most beneficial SPL bushing would be the front LCA inner and compression arm bushing. How long they last on the road, no idea. But I daily drive mine for over 20k miles before my car turned into track only
Ok thanks,
My car does less than 3k miles a year on the road. (and about 1k mile on the track) So it should be ok for some time then.
The Z is nearly a track car only. For my daily drive i have a very good and fast Renault Sport Megane 3 RS 275 (the former faster FWD car on the nurburgring ^^, perhaps still the fastest since the type R was clearly not stock in the way it build speed on its record compared to stock ones ^^)
i found my car was faster than same Z with aftermarket sway bars. My Z is indeed very fast, or i'm a faster driver than the one i met don't know.
The near square tires setup is praised here, in fact my 265/35 front toyo are in real wider than my 275/40.
Being faster that a same Z with XXX part does not mean much when there are so many adjustable variables. Also the near square setup only works when the rest of the car is right.
Your mentioning toe per axle, do you have it by tire? You could have one tire at 0 and the other with all of your measured toe. That would cause one side to do as your saying.
What hot tire pressure are you running?
I second what the others are saying in regards to shock travel and corner balance.
With so many suggestions it can be hard to nail it down so I suggest making a step by step so you don't miss something or undo something you did earlier. This can also become part of your pre track checks.
I would do something like:
1. check ride height and travel.
2. Corner balance the car.
3. Align the car.
4. Set or remove pre loads
After that you can make small adjustments at the track with shock settings and tire pressures to fine tune the feel.
Also a real differential will make a world of difference. The factory VLSD is garbage.
BC Racing ER Coilovers, about 5cm lower than stock. (on the track: compression 30/30, rebound 20/30. 12kg spring front 10 kg spring rear)
- Cusco Front Upper Arms
- Stock sway bars
- Enkei RPF1 9.5*18 ET15 wheels
- 265/35 18 Front Toyo R888 tires
- 275/40 18 Rear Toyo R888 tires
Does this coilover setup place the rear springs in the oem spring bucket or on the rear shock body?
What are the coilovers rebound and adjustment setting range?
The R888's how far are you from the wear bars at all four corners?
Being faster that a same Z with XXX part does not mean much when there are so many adjustable variables. Also the near square setup only works when the rest of the car is right.
Your mentioning toe per axle, do you have it by tire? You could have one tire at 0 and the other with all of your measured toe. That would cause one side to do as your saying.
What hot tire pressure are you running?
I second what the others are saying in regards to shock travel and corner balance.
With so many suggestions it can be hard to nail it down so I suggest making a step by step so you don't miss something or undo something you did earlier. This can also become part of your pre track checks.
I would do something like:
1. check ride height and travel.
2. Corner balance the car.
3. Align the car.
4. Set or remove pre loads
After that you can make small adjustments at the track with shock settings and tire pressures to fine tune the feel.
Also a real differential will make a world of difference. The factory VLSD is garbage.
Thanks for your answer.
It seems it's better since i put back in place correctly the rubber under my right rear spring.
I also put 1.5cm more up travel on both rear shocks.
I will put a Quaife Helical LSD this spring. My traction is really bad.
Need to find where to corner balance the car now...
It seems it's better since i put back in place correctly the rubber under my right rear spring.
I also put 1.5cm more up travel on both rear shocks.
I will put a Quaife Helical LSD this spring. My traction is really bad.
Need to find where to corner balance the car now...
I just bought the Quaife. Will be installing this Spring unless my impatience gets the best of me. I'm sure it will be light years ahead of the VLSD. Well at least I hope
my rear traction bars/arms bushings are begining to crack :
And i also found that my diff bushings are quite in the same shape...
Could it cause my sloppy oversteer problem ? (more the traction arms bushings than my diff bushings of course).
What is the common symptom of dead rear diff bushings ? the 2 front ones are ok, but the rear one on the subframe seems to be crushed : the bolt is not centered anymore, the rubber is flattened)
Common symptom of the rear diff bushing is a trail of fluid residue leaking from it. If you have tracked the car at all its likely done, especially if your other bushings are cracking.
Go with a solid rear bushing, don't waste money or time on any of the poly bushings, they are not made for the track.
Common symptom of the rear diff bushing is a trail of fluid residue leaking from it. If you have tracked the car at all its likely done, especially if your other bushings are cracking.
Go with a solid rear bushing, don't waste money or time on any of the poly bushings, they are not made for the track.
I have nothing like a trail of fluid leaking from my rear diff bushing for now. but it seems it is flatened..
Does it seems to be right ? To low on the front ? I heard some of you said that too much low is not good : i was considering lower equals lower gravity center equal better handling and response..
Ground to arch will be different depending on tire. Will post mine shortly
656mm front
667mm rear
285/35-18 front and rear
Thanks, yes i will calculate that considering you tire height. i will have to make also measurment with my track wheels, because 645mm front was with 245/35 19 road tire not my 265/35 18 track tires.
So after a quick calculation, you are 10mm higher in term of suspension front and rear considering you tire height.
when i'm on my track wheel you wheel arches are 16mm higher in front.
Don't think it's a good thing that my front wheels are 35 profile front and 40 rear for the track. 265/35 18 front and 275/40 rear. i should consider 275/35 rear or 265/35 to have a real square setup...
Yesterday i raised the front by 15mm to 660 mm, didn't drove the car yet. i will put it back to around 655mm i think. i should also raise a bit my rear...
12-05-2015, 09:34 AM
