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What prevents a supercharger from being run on an AT?

Tinkles
To install it on the engine itself, nothing. Just install it and keep the power level at 250whp or less for maximum reliabilty. But clearance between the serpentine belt and fuel tank might be an issue with a supercharger or having enough room to fit all of the pluming for a turbo system might be an issue with the turbocharger. Either way if you expect to have to do a little bit of custom fabrication work then you should be ok.
 
Adam
Doing that on an AT Goblin won't be a problem. It'll work the same as a supercharger on an automatic Goblin.

The reason we don't offer an SS/SC Goblin AT kit (or any manual AT kits) is because of the manual transmission and the Cobalt gear ratios. The gear ratios work out well on the street with Cobalt sized tires but they aren't great for slow speed, off road climbing especially when you add in taller tires to the equation.

Throwing 31 inch tall tires on the car will lead to drivability issues especially when it comes to climbing up steep trails. Imagine climbing a tough trail at 5 mph. With the SS/SC gearing, your engine would only be turning 675 RPM. This is below the usual idle RPM. You'd likely have to slip the clutch to keep the engine from stalling because it is turning so slowly. I can't imagine the clutch would last long doing this. With the automatic, the torque converter takes care of this for you.
 
C
Adam said:
Doing that on an AT Goblin won't be a problem. It'll work the same as a supercharger on an automatic Goblin.

The reason we don't offer an SS/SC Goblin AT kit (or any manual AT kits) is because of the manual transmission and the Cobalt gear ratios. The gear ratios work out well on the street with Cobalt sized tires but they aren't great for slow speed, off road climbing especially when you add in taller tires to the equation.

Throwing 31 inch tall tires on the car will lead to drivability issues especially when it comes to climbing up steep trails. Imagine climbing a tough trail at 5 mph. With the SS/SC gearing, your engine would only be turning 675 RPM. This is below the usual idle RPM. You'd likely have to slip the clutch to keep the engine from stalling because it is turning so slowly. I can't imagine the clutch would last long doing this. With the automatic, the torque converter takes care of this for you.
Click to expand...

Kind of surprised by that, actually... first gear on the SS/SC/Redline is pretty low. I mean, not rock crawler low, but lower than I'd like for street use.
 
AZmoto
I'm torn here.

1) I like the looks of the AT better.

2) I would like a dual sport vehicle that gives up little on the street but can hit the unpaved desert roads as well.

3) I have no interest in rock crawling. I just want a little more ground clearance. Maybe a little more suspension travel.

4) I would really prefer the lnf turbo/manual transmission as I have been modifying this combo for years and have a lot of experience and parts.
 
C
AZmoto said:
I'm torn here.

1) I like the looks of the AT better.

2) I would like a dual sport vehicle that gives up little on the street but can hit the unpaved desert roads as well.

3) I have no interest in rock crawling. I just want a little more ground clearance. Maybe a little more suspension travel.

4) I would really prefer the lnf turbo/manual transmission as I have been modifying this combo for years and have a lot of experience and parts.
Click to expand...
This is pretty much exactly why I'd be interested in it, too.
 
Desert Sasqwatch
Adam said:
Doing that on an AT Goblin won't be a problem. It'll work the same as a supercharger on an automatic Goblin.

The reason we don't offer an SS/SC Goblin AT kit (or any manual AT kits) is because of the manual transmission and the Cobalt gear ratios. The gear ratios work out well on the street with Cobalt sized tires but they aren't great for slow speed, off road climbing especially when you add in taller tires to the equation.

Throwing 31 inch tall tires on the car will lead to drivability issues especially when it comes to climbing up steep trails. Imagine climbing a tough trail at 5 mph. With the SS/SC gearing, your engine would only be turning 675 RPM. This is below the usual idle RPM. You'd likely have to slip the clutch to keep the engine from stalling because it is turning so slowly. I can't imagine the clutch would last long doing this. With the automatic, the torque converter takes care of this for you.
Click to expand...
Adam is correct. The difference in tire size alone - going from the stock Cobalt diameter (@25.5 inches) up to a 31 inch diameter tire easily reduces your overall gearing ratio by 21%. That's 21% less felt torque and 21% percent less RPM for a given tire speed. A manual transmission, being directly coupled between engine and wheels, will sometimes require feathering the clutch in certain situations - and increased clutch wear. The automatic transmission, being fluid coupled, will allow for slippage in those situations and increase drivability.
I'm not saying that a manual transmission could not used in the AT, far from it that I would want to tell anyone what to do with their Goblin. With the correct gearing (4.05:1 from a SAAB or Opel) and the right clutch would probably make the AT a really fun ride with a manual trans. Just be aware of the laws of physics that sap out that 21% torque (and fun). :)
 
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C
According to the Cobalt forum guys, there actually were 4.45 gears available at one point, but they're rarer than hen's teeth now. Pretty sure you could still get them for the right price, but 4.05's from an SS/SC are probably the best you're going to find for a reasonable price. (Nuker's right, SC's are 4.05, TC's are 3.82)

Source: https://www.cobaltss.net/forums/drivetrain-79/4-45-gears-update-302836/
 
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K
This site offers 4.45 final drive ratio for $550. With a larger final drive i bet you could use taller tires. Possibly equivalent to smaller tires with smaller final drive
 
K
1) I like the looks of the AT better.

2) I would like a dual sport vehicle that gives up little on the street but can hit the unpaved desert roads as well.

3) I have no interest in rock crawling. I just want a little more ground clearance. Maybe a little more suspension travel.

4) I would really prefer the lnf turbo/manual transmission as I have been modifying this combo for years and have a lot of experience and parts.
[/QUOTE]

Same here!
 
C
Ken R. said:
This site offers 4.45 final drive ratio for $550. With a larger final drive i bet you could use taller tires. Possibly equivalent to smaller tires with smaller final drive
Click to expand...

Nice find... I'd be curious to know where they sourced the gearsets from. Regardless, we know there's room for a 4.45 combo in there.

If you're running a TC setup, switching from 3.82's to 4.45's (assuming going from 25.5" to 31" tires, from 80.1" to 97.4" circumference) will give you almost the same wheel speed per output shaft revolution. Only an increase of about 4%.

If you're running an SC 4.05, then going to the 4.45 won't give you much more reduction than you've already got... will increase wheel speed by around 8% overall with the bigger tires. (This is where I'd probably be)

Cheapest option, if you go from 3.82's to 4.05's, again assuming putting 31" tires on, it's a roughly 14.3% increase overall.

Of course, this is rough quick math, but... still better than 21% from just tires.
I kinda still want to do this.
 
C
comegetjoe said:
Thats good to know. My 09 ss/tc donor currently has a 4.05 transmission in it.
Click to expand...
Think it was replaced at some point? Can you check the numbers on it?
I mean, we're going off of numbers posted from GM on the internet... but it might be within the realm of possibilities. Stranger things have happened.
 
comegetjoe
CajunJeff said:
Think it was replaced at some point? Can you check the numbers on it?
I mean, we're going off of numbers posted from GM on the internet... but it might be within the realm of possibilities. Stranger things have happened.
Click to expand...

Yeah. Supposedly it was a replacement trans at some point. I didn't get to drive am ss/tc sedan, but 4.05 is definitely a welcomed gear set in the coupe.
 
Ross
CajunJeff said:
Nice find... I'd be curious to know where they sourced the gearsets from. Regardless, we know there's room for a 4.45 combo in there.

If you're running a TC setup, switching from 3.82's to 4.45's (assuming going from 25.5" to 31" tires, from 80.1" to 97.4" circumference) will give you almost the same wheel speed per output shaft revolution. Only an increase of about 4%.

If you're running an SC 4.05, then going to the 4.45 won't give you much more reduction than you've already got... will increase wheel speed by around 8% overall with the bigger tires. (This is where I'd probably be)

Cheapest option, if you go from 3.82's to 4.05's, again assuming putting 31" tires on, it's a roughly 14.3% increase overall.

Of course, this is rough quick math, but... still better than 21% from just tires.
I kinda still want to do this.
Click to expand...
The 4.45 differential came from a Saab 9000 naturally asperated 2.0L and 2.3L engines according to this forum.
 
Rauq
Just to back up a little bit, the F35 transmission came in factory FI Cobalt, while the NA Cobalts got the F23. I believe there's some interchangeability with attention paid to the flywheel, but you can do your own due diligence there.

In order of ascending gear ratios, here's the US GM applications:
AppliactionTransGear Ratio
Cobalt XFEF233.63
Cobalt SS/TCF353.82
Cobalt NA (including SS/NA) + early HHRF233.84
HHR (2009-10) + older GM (Cavalier, etc)F233.94
Cobalt SS/SCF354.05
Saturn VueF234.41

The comparison I did in the other thread included a setup with the Vue trans with a 30% underdrive if you fitted some UTV portals or something like that.
 
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