Tag

 

Car will look and go awesome!

 

I'm glad I came back in this thread and noticed this. You're still on the Swift Rs and Koni yellows correct?

I've been thumbing over this idea, but always get swayed by other with "coilovers this and that", but it's to my understanding that unless you're going super high end they're all made in the same place anyway.


Awesome build man, keep up the good work

 

Yeah Koni Yellow and Swift Spec R.

I do get the feeling that you would have to go high end to out perform it. Like at least KW Clubsport. But thats a guess.

If I had to do it over I would have gotten the threaded collars for the Konis and gotten it corner balanced right out of the box.

 

And have you been periodcally adjusting the dampening to compensate for all the weight loss from the chasis?

 

Yes I make a lot of adjustments. I had the car sorted out, then I added the front camber arms and an aggressive alignment. That created massive oversteer. So I had to spend another entire day sorting it out. Now I've added aero and stickier tires, so its going to take 1 or 2 days again to get it sorted out again and I will be breaking in the new clutch at the same time.

 

I've just broken in my JWT clutch/fly about 300 miles on it. It's amazing. The pedal feel,how quickly it rebounds after an upshift, the deceleration.

So much better than the act/fidanza set I was running prior

 

So I'm doing more studying/ bench racing because I'm stuck in the house and both kids are napping.

This is the effect of mass on lap time at TMP.
This is a typical DE with bolt ons or stock HR. 263 rwhp.
The green line/ time is a totally stripped out stock car. 1375 kg with driver and fuel.
Thats a 3025 lb car. Lighter than mine. Optimum time on star specs is 1:20.54

The purple line is a full weight car. 1690 kgs! 3718 lbs! That's like roadster or fat driver.
It's predicted time is only 1 second slower! That yields a roughly 700 lb per second ratio with our power levels and grip levels at TMP! That is both depressing since I destroyed my car. But reassuring since I will be going up against lighter cars.

The moral of the story. Tires are everything.

Even checking at other circuits around the world yields the same result. The f1 circuit at catalunya... 2:12 vs 2:14 for 700 lb weight difference.

 

^ That's a little disheartening.

 

2TH, I couldnt sleep last night so I watched your youtube videos on your channel like a teenage girl looking through Justin Bieber's window

 

Wow this is getting creepy.
I actually joined a Bieber fan club recently titled " Cut Yourself for Bieber ". It's pretty neat.
You just cut yourself where no one can see and then when you go to sleep Justin Bieber will visit you in your dreams!

 

http://www.hotrod.com/projectbuild/h...t/viewall.html


I don't think you did anything in vain or anything that won't show even the slightest gains...

Only gripe is the fenders but even that technically has a purpose!

 

Yeah, to anyone reading this I would just suggest that if you want to go faster in a 350Z, remove the easy to remove things, pay attention to tires, suspension damping and alignment, and get a clutch based LSD and you will have a fast track car. Yes a completely gutted Z might be a half second faster but you have to ask yourself if that half second is worth it. To me... HELL YAH! lol.

Power is important, but not as important as the things I've listed above.

 

Where are you getting the data for that? It looks to ONLY take into consideration the increase in acceleration, but does not take into any account of shorter braking time, as well as faster corner speed.

A lighter car simply corners faster. Less mass to change directions. Thing the hair pin, you think if you added 1000lbs to the car you could move around it as fast? Do you think you could brake as late as you could with 5 passengers?


The green line would brake later, brake less. Your graph is wrong :P

 

There is such a thing as to light,which is where aero comes in

 

You are kinda right. But tires are what's stopping the car and tires are what's turning the car. If you look at the braking points the lighter car is actually braking slightly earlier because it's coming in hotter. The slope of the deceleration is dependant on the tires co-efficient of friction. Which for all intents and purposes is equal at our grip levels.

I'm not saying weight plays no role. But the 100 lbs/ second argument in a street car seems to fall apart. This is is showing like 650 - 700 lbs per second which might be extreme. The reality probably falls closer to 400 lbs / second, which is about as much as you can take off a 350Z yourself. You are better off to take out the tools, the tire, the passenger seat, buy lightweight wheels and exhaust, and achieve most of the benefit at a fraction of the effort. Because studies show the most important weight you remove is the first weight you take out. More and more weight shows less and less benefit. It's an exponential curve. To the point where more reduction is just no benefit at all.

At the relatively low cornering speeds of a track like TMP, max achievable mid corner speed is close to the same.

And this is also a comparison of optimum vs optimum with a 19% difference in weight between the two cars which are otherwise identical. The heavier car will probably fall off faster.

But in time attack, all that matters is that one best lap where your tires are up to temperature.

 

one lap...to rule them all

 

Well you are crazy if you think a 3700lb, 260hp ZR on Star Specs will do a 1:21. Add 3 or 4 seconds to it and you might get there. That right there should be proof enough.


The tires traction are directly ruled by the amount of force on them. The amount of force on them is directly ruled by the mass of the car. Ever seen a go-kart in action? Skinny *** tires but could pull that hair pin faster than you ever can, and has 1/10th the power.

Formula Vees pull the same lap times as Matt at MIR, only they do it with 40hp and skinny all season tires and no aero. If you think its power to weight, they weigh about 800 lbs (20:1 weight to power is pretty weak!).

Or look at Jimbo around TMP. Hes in a FWD honda with 250hp running sub 1:20s on streets. Then again, his car weights less than ours without an engine!


I dont think the car coming in faster will brake sooner, as it doesn't have the same amount of mass to slow down. It will also brake to a faster speed, since it can move around the corner at a faster speed so it has a fast entry and exit. In fact that green line should be above the purple in every point, top and bottom.



I dont agree that 100lbs = 1 second around TMP, never have. The general rule was .1 for every 10lbs in a FF around a power track like MIR (mostly in the back uphill straight). In a road car at TMP hard to say, but I bet its close to .5 seconds depending on how much it throws off the balance (taking 400lbs off the outside rear might hurt more than it helps for example).

 

Not saying the simulation by Optimum G is perfect. Its not. But just advising Z owners, just take out the easy stuff!
ZR. Weight ~3650 with driver. Power 220 whp? coilovers and RS3s.

I pull him down the straights. The rs3s are better tires slightly but i'm only slightly faster through most corners, except for T10 where I noticed I am significantly faster. But that is not physics. That is line selection. I think tim could have used 2nd gear to gain more speed in T6 exit. T10/ 11 complex could be more aggressive.

 

Agreed Mike. I most definitely should be in 2nd coming out of turn 6. I think there are a couple different exits I could benefit from being in 2nd too.

If that program is any where near accurate, it definitely isn't worth the aggravation. But the more I think about it it, the less sense it makes. 700 lbs is alot. Look at cars like the s2000, frs, or the lotus on the more extreme end. Although being down on hp, they seem to be quick on road courses right out of the box because of their ability to carry speed through the corners which I thought is highly attributed to their low weight. You would think the Z that is 700 lbs lighter would simply do everything a little bit quicker. Quicker acceleration, quicker braking, quicker steering response, quicker transitions, and ability to carry higher speed through the corners translate to a much better time than 1 sec.