What prevents a supercharger from being run on an AT?

Tinkles

Well-Known Member
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

Administrator
Staff member
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.
 

CajunJeff

Member
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.
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

New Member
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.
 

CajunJeff

Member
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.
This is pretty much exactly why I'd be interested in it, too.
 

Desert Sasqwatch

Goblin Guru
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.
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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Ken R.

Member
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
 

kellymax11

New Member
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!
 
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