A C5 Z51 with stock tires does 78mph at 6000 rpm. The stock diameter is 26.7" and switching to a 285s with a 24.9" dia drops top 73mph.

Stock limit is at 7600rpm, On stock valve springs you shouldn't have any problems with a bit more over-rev to 7900-8000. I believe Aaron at English Racing said 8200 was the limit on stock spring/cams before floating. 8000 rpm would get an Evo IX to around 68mph.

 

on short tires (285 or 245), 8k rev limit gets you 65mph in an evo.

 

For a 24.8" tire, the math says its 66.7 @ 8000rpm :P

 

You guys can't let the trainy just to shift to 3rd??

 

I found some numbers for a stock 2003 350Z (Track)

TOTAL....3118 lbs
LF...849 lbs
RF...886 lbs
LR...697 lbs
RR...687 lbs

Front 1735 - 55.6%
Rear 1348 - 44.4%

Someone else also posted motion ratios for their 350Z
.688 F and .649 R (*squared)

Brian posted last year (STR trim)
Spring Rates: 1000/850. Wheel Rate = 473/358~ish(edit) (a typical EVO 10/12k setup's WR = 515/400~ish)
Power: 265HP and 250ftlbs of torque on a Dyno Dynamics. 12% correction for DynoJet = roughly 297HP and 280ftlbs +/- (edit)
Weight: 3100lbs

My car recently weighed in at 3197lbs
Front 1980 lbs - 62%
Rear 1217 lbs - 38%


these are the numbers from our latest corner balance, spring of 2014. EVO IX GSR

275/35/18 RS3’s - tread width (measured on a 9.5" rim) = 10.2"
285/35/18 RS3’s - tread width (measured on a 10" rim) = 10.1"
245/40/17 RS3’s - tread width (measure on a 8.5" rim) = 9.1"

...math

 

So we agree that AWD cars in STU need wider tires?
If so what should be the tire size? 255, 265, 275? - I do not see any Evos or STIs being able to fit 285s or wider under the STU rules…

Should we all send letters (I have done that before but it was denied)
Could we compose a letter gathering all the facts & data available in this thread to make it easier for everyone; people could change or add anything else to this letter or keep it the same if they agree with the original letter.

 

Well, since you dropped those numbers above, you could have added this one as well:
275/35/18 RS3’s - tread width (measured on a 9.5" rim) = 10.2"

Although, all the numbers are from the Tire Rack, I think it was posted elsewhere that 285s are wider than 275s in real life.

One more detail here is that 275s are a bit shorter than 285s as well - 25.6 vs. 25.9

Another thing to consider is to see if there are any 285/30/18, since those would be even shorter for better gearing.

Edit: just checked few others and Rivals are the same as RS3s, but ZII have 285/30/18 and they are even wider and shorter than those two: 10.7" width and 24.8" for OID - if they would just offer contingencies...

 

Interesting. I recall Nissan's own advertising and literature claiming a 53:47 weight distribution. The marketing story was that 53:47 was superior to 50:50 because it was more ideal once load transfer due to acceleration was taken into account.

By the logic, our 62:38 weight distribution should be even better under even more acceleration. Right?

I guess the 350Z probably loses weight from the rear of the car easier than the front, much like the Evo.

 

Multiple people sending identical (or nearly identical) letters isn't going to help our case.

Each letter needs to be individually written, polite, professional, and reasonable.

But I do agree that we should try to settle on the most straightforward change set, or even one single change, that would level the playing field. Bringing 08+ Evos and STIs into the fold should be a high priority too, IMO.

 

truth. it is no coincidence that the fastest way to drive an evo is slow-in/fast-out.

but it doesn't mean 62:38 is quicker than 50:50 or 40:60 for turning. it's just better at straight line accel when AWD.

 

I have no idea how they interpret or review the letters. I was thinking that they will see it as signing a petition; it is the same document and everyone signs it if they agree? But I may be wrong.

Either way we should ask for a similar change; either increase size width for AWD or decrease width for RWD or both.
2003-2007 = 255
2008-2015 = 275
RWD cars = 275

 

They actually read the letters. The board is composed of reasonable human beings.

Having year-specific or vehicle-specific limitations is not an option. We'll have to keep it simpler than that.

I think removing the AWD tire restriction is the most straightforward approach here. Keeps the rules simple and it's not an unreasonable request.

However, we should compile a list of fact-based reasoning for people to pull from in their letters. Current nationals results, the rough weight balance/power math from this thread, etc.

 

I'm in a sharing mood. Here's the numbers from our latest tune, Spring of 2014, post motor rebuild.


DynoJet
304HP and 292ftlbs of torque

here's what Brian posted, "Dyno from just before (2013) nationals showing the 100 octane tune vs 91" (STR trim)

 

Am I reading something incorrect or your numbers are quite higher than his? 304/292 vs. 268/250 from what I can see...

 

correct, STU EVO vs 350Z