Final drive swap

JSATX

JSATX

Goblin Guru
It sounds like the consensus is wait and see. I’m nearing finishing my new engine build so I won’t run out and buy a different one just yet.

I will still say the 3.63 is too tall for my current 220hp engine. Sounds like I should get a different trans for that one and maybe move my current one to the big engine.
 
Ross

Ross

Goblin Guru
So SliderR1, Lonny and I are all driving ~205hp LSJ SC goblins witk 4.05 diffs, running tires that are the stock highth?
My 1st gear is good until about 40mph, second, 70mph.

I'm not sure I am getting a full 205hp yet, as my car isn't instantly at red line in first...
Unless I do a clutch dump at 4500rpm... then the tires just spin and I hit redline. (Lol... I have never been on a prepped drag track.)
Dragy said I did a 0-60mph in 3.9 seconds yesterday, but the road was a bit downhill, so it doesn't count.
 
KLMOTORSPORTS

KLMOTORSPORTS

Well-Known Member
Lonny said:
My biggest problem is first gear is instantly at red line. I feel I need a taller final drive as it is. If I were to up the power I would most definitely need to change
Click to expand...
This is what I believe I will run into with mine in Autocross (F40 Regal trans)....launch in 1st and immediately into 2nd...pondering on how much power is really “value added” in this situation....would think 250-300 is about max “useable power” in Autocross based on the weight of the Goblin...
 
Desert Sasqwatch

Desert Sasqwatch

Goblin Guru
Keep in mind the transmission designator defines the torque capability of the transmission, in terms of the stock limit:

F23 = 230 Nm = 170 FtLbs
F35 = 350 Nm = 258 FtLbs
F40 = 400 Nm = 296 FtLbs

Before anyone jumps in, yes these torque ratings are based on a 3000 + pound vehicle. With the Goblin being roughly 1/2 the weight, a conservative estimate of torque rating can be reached by multiplying each torque value by 150%. This should give a good estimate of the maximum long-term torque rating for a stock transmission to live in a Goblin with a reasonable amount of 'abuse'.

F23 = 255 FtLbs
F35 = 388 FtLbs
F40 = 444 FtLbs

If you are planning to up the 2.2 liter horsepower, and torque, the engine with a supercharger (possibly) or turbo (more likely) mated to the F23 transmission may not hold up under long term 'abuse'.

Since a better gear ratio is desired from the stock F23 final ratio, it may be desirable to locate a F35 transmission. This is just my 2 cents on this item. :)
 
JSATX

JSATX

Goblin Guru
Theoretically you're right. But if you search there's literally hundreds of accounts of the F23 being run to over 300HP in the cobalt and cavalier.

Even the Wiki page for the F23 mentions it: "It also has a following in the ecotec racing community for being able to handle 700hp with an LSD insert and only costing about $200. It does not have the problems that plague the F-35 found in the SS, so it makes for a good transmission swap candidate."

I plan on sticking with it. Sure if I blow more than one or two, it's time to figure something out. Until then I plan to keep it.
 
Desert Sasqwatch

Desert Sasqwatch

Goblin Guru
Since there are many transmission swaps occurring lately, I pulled up this thread for those who have not seen it before. Post #26 above provides some of the manufacturers information about the F23, F35 and F40 transmissions - published torque ratings and some assumptions putting these transmissions into a Goblin that is approximately 1/2 the weight of a Cobalt.

Thought I would also provide some additional information about the gearing for each transmission. The gear ratios and splits between gears can make a big difference in the acceleration and cruising RPMs that each one can provide.

In the below is provided the gear ratios, shift mph when selecting the next gear at redline, and the rpm the shift drops down to. Please note all the data provided is based on the stock sized 25.0 inch tall tires and shifting at 6200 rpm stock redline.

F23 - with 3.84 ring & pinion
1st (3.58) Shift to 2nd - 34 mph - rpm 3500
2nd (2.02) Shift to 3rd - 59 mph - rpm 4145
3rd (1.35) Shift to 4th - 89 mph - rpm 4500
4th (0.98) Shift to 5th - 123 mph - rpm 4365
5th (0.69) Cruise at 70 mph - 2500 rpm

F23 - with 4.17 ring & pinion
1st (3.58) Shift to 2nd - 31 mph - rpm 3500
2nd (2.02) Shift to 3rd - 55 mph - rpm 4145
3rd (1.35) Shift to 4th - 82 mph - rpm 4500
4th (0.98) Shift to 5th - 113 mph - rpm 4365
5th (0.69) Cruise at 70 mph - 2700 rpm

F35 - with 3.82 ring & pinion
1st (3.38) Shift to 2nd - 36 mph - rpm 3230
2nd (1.76) Shift to 3rd - 69 mph - rpm 4160
3rd (1.18) Shift to 4th - 102 mph - rpm 4675
4th (0.89) Shift to 5th - 136 mph - rpm 4875
5th (0.70) Cruise at 70 mph - 2500 rpm

F35 - with 4.05 ring & pinion
1st (3.38) Shift to 2nd - 34 mph - rpm 3230
2nd (1.76) Shift to 3rd - 65 mph - rpm 4160
3rd (1.18) Shift to 4th - 96 mph - rpm 4675
4th (0.89) Shift to 5th - 128 mph - rpm 4875
5th (0.70) Cruise at 70 mph - 2650 rpm

F40 - 3.76 ring & pinion
1st (3.92) Shift to 2nd - 31 mph - rpm 3230
2nd (2.04) Shift to 3rd - 60 mph - rpm 4000
3rd (1.32) Shift to 4th - 93 mph - rpm 4460
4th (0.95) Shift to 5th - 129 mph - rpm 4960
5th (0.76) Shift to 6th - 161 mph - rpm 5060
6th (0.62) Cruise at 70 mph - 2200 rpm

This is being provided as general information.
 
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