emilio700

iTrader: (3)

Compared to my AP1, the ND feels far more responsive and quick around town, stock for stock. A stock NB2 feels slower than both. NB2 engine with I/H/E , square top and ECU is quicker than both

18psi

iTrader: (76)

plot/determine the actual accelerative torque vs weight being accelerated up to 3-4k

And to at least somewhat keep this on topic: keep in mind that the ND has extra funky gearing that is really helping it's thrust and torque curve and probably why everyone is so impressed with how they drive

sixshooter

iTrader: (12)

So the s2000 weighs at least two 250 lb fat chicks more than the Miata. That's pretty hard to hide with a 20-25 hp difference below 6200 rpms. Maybe if it made 40 hp more than the Miata when off Vtec, but... those are some pretty big chicks to hide in the trunk and not notice it around town. So I call bullshit.

aidandj

iTrader: (5)

<p>You haven't seen the kind of chicks ben rolls with.</p>

aidandj

iTrader: (5)

<p></p><p>Drag race time </p>

18psi

iTrader: (76)

haha exactly Steve.
in fact, I just did some calculations, not fancy with a spreadsheet mind you, I'm just a peasant and in the middle of a teleconference so correct me if I'm wrong:
not taking tire diameter into consideration, between 2-3k, in 1st gear
s2k
.567tq/lb
nb2
.584tq/lb

I'll have to re-do this properly with tire diameters when I'm not busy.

*edit:

for those that are bored:
AP2
~125tq 2-3k rpm
wt: 2835
tire dia: 24.72
3.133
2.045
1.481

NB2
~95tq 2-3k rpm
wt: 2387
tire dia: 23.26
3.760
2.269
1.645

Dunning Kruger Affect

I'm the Atkinson cycle F20C/F22C powered S2000.

concealer404

iTrader: (3)

Before i share my findings... As a real ghetto way to calculate "thrust" at a given RPM, does anyone have an objection to this?

(final drive * gear ratio * ftlbs @ given rpm)/weight


Ok actually that's exactly what Vlad did, unfortunately Vlad... you've missed a very important part. The S2000 trans has a reduction of 1.208. If you run your numbers exactly as you did through a gearing calculator, you'd end up with a top speed in 2nd gear for the AP2 north of 70mph, and we know that's not the case.

When i did the same calculation at 2000rpm, i got 0.581ftlbs/lb for NB2, and 0.691ftlbs/lb for AP2. At 3000rpm in 1st, the difference is quite a bit larger. 0.614 for Miata, 0.816 for S2000.

Accounting for tire size difference, at best, MIGHT put them in a tie. Which by definition, does NOT support "S2000s are slower around town than Miatas."


Here's what my maths came up with. I mapped 1-2-3-4 gears at 2000, 3000, and 4000rpm.

S2000 1st gear: 0.691, 0.816, 0.816
S2000 2nd gear: 0.393, 0.464, 0.464
S2000 3rd gear: 0.285, 0.336, 0.336
S2000 4th gear: 0.223, 0.264, 0.264

NB2 1st gear: 0.581, 0.614, 0.614
NB2 2nd gear: 0.351, 0.37, 0.37
NB2 3rd gear: 0.254, 0.268, 0.268
NB2 4th gear: 0.194, 0.205, 0.205

aidandj

iTrader: (5)

<p><img src="http://cimg8.ibsrv.net/gimg/www.miataturbo.net-vbulletin/709x532/80-thrsteq_f13943a273c2881d8bd8312e184717519344e933.g if" title="" /><br /><br />&nbsp;</p>

codrus

(torque (in ft-lbs) * tranny ratio * rear end ratio) / wheel+tire radius in feet == force (in pounds). Divide that by mass and you get acceleration.

--Ian

concealer404

iTrader: (3)

Ok cool, that's a very small adjustment. One sec!

concealer404

iTrader: (3)

Revised using the correct formula taking tire diameter into consideration.

Car, gear, 2000, 3000, 4000.

AP2 1st: 0.67, 0.792, 0.792
AP2 2nd: 0.381, 0.451, 0.451
AP2 3rd: 0.276, 0.327, 0.327
AP2 4th: 0.217, 0.256, 0.256


NB2 1st: 0.6, 0.633, 0.633
NB2 2nd: 0.362, 0.382, 0.382
NB2 3rd: 0.262, 0.277, 0.277
NB2 4th: 0.201, 0.212, 0.212


This is pretty cut and dry. Can we put this dumb crap to bed now? Tell all your friends? Maybe email blast to all the Miata.net forum members?

aidandj

iTrader: (5)

Add ND

concealer404

iTrader: (3)

Maybe tomorrow. ND might be faster, so that would be cool.

18psi

iTrader: (76)

I won't double check the math. I'm assuming you did it right.
so they're close?
so basically both are slow around town?

Sav didn't even say they're slower than a miata, you just put that in there for dramatic effect. The point is they're not much faster, and suck.
The difference is not as dramatic as you thought it was, is it? And agian, that's taking the differently corrected dyno's as the base tq measurement and guesstimating.

Now put in the ND like aidan said.

aidandj

iTrader: (5)

<p>Sav may not have said it, but ben's right. That **** is repeated everywhere you go.</p><p>People do make the &quot;but AP2&quot; argument. I would rather have seen an AP1 vs NB2, they line up production years better anyways.</p><p>Make the spreadsheet easy to use and upload it to google sheets. This might go somewhere.</p><p>Would be easy, power at different levels, gear ratio, tire size, weight.</p>

concealer404

iTrader: (3)

The thing is... what looks like really small number differences on paper there is actually pretty big.

I don't think anyone here actually said that they were actually slower around town, it's just amusing to me that the biggest detractors of the S2000s low end performance seems to be Miata owners, like they have to find a fault with the car.

"But it sucks so bad to drive around town!!!....... despite being faster than my car in every situation."

I just have pet peeves. This is one of them.

I knew you were going to point out the dynos. Go ahead and find me an NB2 on Church's dyno or something. ilu

ND tomorrow. Maybe. If i care. I already know i like the ND, i don't need to validate it against a car not being made anymore.


If i have a slow spell tomorrow i'll add ND and AP1. And NB1 with my gearing setup.

My spreadsheet isn't easy to use, i suck at excel. I manually entered everything.

aidandj

iTrader: (5)

<p>Some people just have to justify why they bought a miata.</p><p>S2ks are cool, but to me a waste of money.</p><p>You should generalize it, then you could do any car.</p>

18psi

iTrader: (76)

aside from being cramped inside, the torque delivery of the s2k is the single biggest reason I don't own one. I absolutely love them otherwise.
it also happens to be the biggest reason I love me my vette's
I also would never have a long term n/a project miata for any reason ever. In fact, if I couldn't boost or swap a miata, I would never own a miata either. Ever.

Mazda really worked on avoiding the torque delivery deficit with the ND, and I'm sure we can all agree that we really appreciate it.

concealer404

iTrader: (3)

Absolutely, no matter how much M.net cries about it, the ND seems to be a huge step forward, and i'm not even someone who gives a single **** about what happens in a sports car below 4000rpms. I agree with you.