LSJ/ECOTEC Transmission info

[Bottoz]

Assuming Brammo keeps the stock gear ratio and final drive... here are the results on a 205/50-15 tire:

Gearbox:-  LSJ
Tyre:-      205/50-15
-------------------------------------------------------------------------------------------
Top Gear gives 24.210 MPH/1000 RPM and a top speed of 157.368 MPH at 6500 RPM

Engine speeds in top gear:-
    30 MPH = 1239 RPM  40 MPH = 1652 RPM  50 MPH = 2065 RPM  60 MPH = 2478 RPM
    70 MPH = 2891 RPM  80 MPH = 3304 RPM  90 MPH = 3717 RPM  100 MPH = 4130 RPM

Top Speed in 1 gear = 32.591 MPH
    And changes into 2 gear at 3385 RPM dropping 3115 RPM
Top Speed in 2 gear = 62.590 MPH
    And changes into 3 gear at 4358 RPM dropping 2142 RPM
Top Speed in 3 gear = 93.354 MPH
    And changes into 4 gear at 4903 RPM dropping 1597 RPM
Top Speed in 4 gear = 123.773 MPH
    And changes into 5 gear at 5112 RPM dropping 1388 RPM
Top Speed in 5 gear = 157.368 MPH
******************************************************************************************

[Lightning]

Damn, now after having the STI I fully realize the benefit of having a 6spd gear box.  I wish GM had that option in an adaptable format for Brammo.

Still, second and third look pretty tasty!

[McFred]

(for comaprison)
Assuming Brammo keeps the stock gear ratio and final drive... here are the results on a 205/50-15 tire with the Honda drivetrain (applicable to UK atoms too):

Gearbox:-    npr3 (if it really is a JDM CTR gearbox)
Tyre:-      205/50-15
-------------------------------------------------------------------------------------------
Top Gear gives 18.47 MPH/1000 RPM and a top speed of 157 MPH at 8500 RPM

Engine speeds in top gear:-
    30 MPH = 1600 RPM  40 MPH = 2150 RPM  50 MPH = 2700  RPM  60 MPH = 3250 RPM
    70 MPH = 3800 RPM  80 MPH = 4350 RPM  90 MPH = 4850 RPM  100 MPH = 5400 RPM

Top Speed in 1 gear = 37 MPH
    And changes into 2 gear at 5400 RPM dropping 3100 RPM
Top Speed in 2 gear = 57 MPH
    And changes into 3 gear at 6000 RPM dropping 2500 RPM
Top Speed in 3 gear = 81 MPH
    And changes into 4 gear at 6800 RPM dropping 1700 RPM
Top Speed in 4 gear = 101 MPH
    And changes into 5 gear at 6800 RPM dropping 1700 RPM
Top Speed in 5 gear = 126 MPH
    And changes into 6 gear at 6800 RPM dropping 1700 RPM
Top Speed in 6 gear = 157 MPH

[Bottoz]

Thanks McFred! 

And Lightning... I agree. 6th would be nice in the US Atom.

[bolus]

Is this the GME F35/5 transmission that is also in the Cobalt SS and Satrun Ion Red line?
http://media.gm.com/us/powertrain/en/pr ... %20LoR.jpg

from here: http://media.gm.com/us/powertrain/en/pr ... LI4ENGINES

[Bottoz]

bolus, I'm pretty sure thats the ones. I browsed some CobaltSS/Ion Redline forums and got the gear ratios.

[Driver]

It's my understanding that there is only the one 5 speed manual tranny and GM has not publicly made available any car with a EcoTec and a 6 speed manual. Is that correct still? I'd like to see a Atom with a useable 1st gear before I get around to ordering mine (at current pace I have plenty of time). I like the idea of a monstrous overdrive for highway cruising and keeping revs down.

[Bottoz]

Anything with a huge power to weight ratio will have trouble grabbing traction in 1st. 1st gear in my Cobra went to 50mph, and I STIL had traction problems.

[DarthChicken]

The ecotec just screams to have some valve springs and head work down to allow for 7500rpm.  If you could get it that high (which honestly should be no problem), 180+mph looks like its possible. 

[Bruce Fielding]

[quote="DarthChicken"]
... 180+mph looks like its possible. 
[/quote]

Sigh...

[DarthChicken]

or maybe a better way to look at it, is that every gear will SEEM taller, because you can get more speed out of it

Assuming Brammo keeps the stock gear ratio and final drive... here are the results on a 205/50-15 tire:

Gearbox:-  LSJ
Tyre:-      205/50-15
-------------------------------------------------------------------------------------------
Top Gear gives 24.210 MPH/1000 RPM and a top speed of 181.575 MPH at 7500 RPM
Top Speed in 1 gear = 37.605 MPH
Top Speed in 2 gear = 72.219 MPH
Top Speed in 3 gear = 107.716 MPH
Top Speed in 4 gear = 142.815 MPH
Top Speed in 5 gear = 181.575 MPH

I like it! 

[bolus]

I cant find the specifics on the aerodynamics but I dont think it would even be possible to get to 180 without a huge increase in HP.  It's just not aerodynamic enough. 

[DarthChicken]

I figure SIR would be a great place to find out.  PIR I don't think would be long enough, unless you end up running without the chicane (but all the clubs run with it for just that reason from what I've seen, to keep folks slowed down).  I say 180mph tongue in cheek though.. 157mph is probably more than enough, I just don't want to run out of gear.

[Jamin]

Nah - a 6 speed would allow SHORTER ratios (like in the Honduh tranny) - which is the LAST thing the Atom needs, lol.  Maybe the lower power versions, but even they can sit & spin in first from what i hear....

No, what it needs is a 20% (or more) TALLER gear set.  If 1st was a tad shorter than the current 2nd and they went from there, that'd be about right for the 220 on up IMHO.  No 6th needed - there's enough weight-to-power surplus here to make 5th even taller than most cars 6th and have room to spare. 

Note:  The LSJ's gearset was designed from the outset for the stage 1's 7k redline.  People were lamenting the barely too tall gearing for two years, then the stage kits were released - and suddenly, the ratios were JUST RIGHT.  Someone want to recalculate that table with a 7k redline? 

[Bottoz]

[quote="Jamin"]
.....  Someone want to recalculate that table with a 7k redline? 

[/quote]

As... you... wish.

Gearbox:-  LSJ
Tyre:-      205/50-15
-------------------------------------------------------------------------------------------
Top Gear gives 24.210 MPH/1000 RPM and a top speed of 169.473 MPH at 7000 RPM

Engine speeds in top gear:-
    30 MPH = 1239 RPM  40 MPH = 1652 RPM  50 MPH = 2065 RPM  60 MPH = 2478 RPM
    70 MPH = 2891 RPM  80 MPH = 3304 RPM  90 MPH = 3717 RPM  100 MPH = 4130 RPM

Top Speed in 1 gear = 35.098 MPH
    And changes into 2 gear at 3645 RPM dropping 3355 RPM
Top Speed in 2 gear = 67.404 MPH
    And changes into 3 gear at 4693 RPM dropping 2307 RPM
Top Speed in 3 gear = 100.535 MPH
    And changes into 4 gear at 5280 RPM dropping 1720 RPM
Top Speed in 4 gear = 133.294 MPH
    And changes into 5 gear at 5506 RPM dropping 1494 RPM
Top Speed in 5 gear = 169.473 MPH
******************************************************************************************