F40 Transmission - Will It Work?

KLMOTORSPORTS

KLMOTORSPORTS

Well-Known Member
I went with the Regal as offered by ZZP...spoke to them and it will work fine with my LSJ SC...they do have steep gears in them, but I’m only concerned with 1st and 2nd and maybe 3rd, so it meets all I want...will be fun!
 
Desert Sasqwatch

Desert Sasqwatch

Goblin Guru
DFG forum, after doing some research I may have come across the right formula for the driveshafts when using the F40 trans with the LNF hubs.

The Regal GS halfshaft mates with the F40 trans on the passenger side and it appears the pillow bearing bracket is the same bracket shape and bolt hole location as the Cobalt (at least 90% sure at this point). The GS halfshaft looks to be in neighborhood of $200 for the entire assembly new.

The Regal GS drive axle inner ends mate to the F40 trans drivers side and outside end of the halfshaft on the passenger side. The inner CV joint (transmission end) for the GS axle appears to be obtainable for about $100 each. Separating the inner CV joint from the SS shafts and installing the GS inner CV joints appears to be feasible. A set of LNF drive axles can be obtained for about $100 for the pair.

I will be calling into GM to ask some questions, maybe I can get some answers, otherwise I will be trying this myself and hope or the best.
 
Brian74

Brian74

Goblin Guru
Desert Sasqwatch said:
DFG forum, after doing some research I may have come across the right formula for the driveshafts when using the F40 trans with the LNF hubs.

The Regal GS halfshaft mates with the F40 trans on the passenger side and it appears the pillow bearing bracket is the same bracket shape and bolt hole location as the Cobalt (at least 90% sure at this point). The GS halfshaft looks to be in neighborhood of $200 for the entire assembly new.

The Regal GS drive axle inner ends mate to the F40 trans drivers side and outside end of the halfshaft on the passenger side. The inner CV joint (transmission end) for the GS axle appears to be obtainable for about $100 each. Separating the inner CV joint from the SS shafts and installing the GS inner CV joints appears to be feasible. A set of LNF drive axles can be obtained for about $100 for the pair.

I will be calling into GM to ask some questions, maybe I can get some answers, otherwise I will be trying this myself and hope or the best.
Click to expand...
If you go on rockauto, they usually provide the lengths of the axle assemblies, both compressed and decompressed, spline counts, ect. Not sure if that helps at all.
 
Desert Sasqwatch

Desert Sasqwatch

Goblin Guru
Brian, yes that information is available and I have been using it for reference in my research. I am asking Kyle for information from the ZZP F40 conversion kit that he bought, so I can attempt to match up the ZZP supplied parts with parts that are available at stores like O'Reilly or Autozone or even from GM.
 
Desert Sasqwatch

Desert Sasqwatch

Goblin Guru
I pulled the trigger this morning and ordered the F40 (MR6) Regal 6 speed transmission (new), plus dual mass flywheel/clutch kit (new). Also purchased a Saab 6 speed shifter (new) to match up with the transmission. I am now committed to utilizing the F40 for my build - working on the purchase of a Quaife LSD next.

Ken, Kyle, looks like we will do doing much more future communication so we can all make this work.
 
KLMOTORSPORTS

KLMOTORSPORTS

Well-Known Member
Definitely look forward to working together and sharing lessons learned. I should have some real good information in the next few weeks....the F40 and ZZP Kit (minus axles...those are expected in 3-4 weeks due to backlog) will ship this week to Adam and Lonnie @ DF and then will see how the integration goes on my chassis...expecting it won’t be too hard, mainly different left side mount and maybe some modification on lower mounts (not sure if ZZP kit uses existing Cobalt rubber mounts, but believe it does...I won’t be using them...mine will be all solid mounts). Excited to see how it goes...I’m sure it will be top notch fab work knowing Adam and Lonnie!
 
Desert Sasqwatch

Desert Sasqwatch

Goblin Guru
Go check out the latest post from Adam for the DoyleFab video reworking some axles. The disassembly of the transmission side looks straight forward and gives me confidence the Regal GS Turbo F40 axle ends can be installed onto the Cobalt SS axles.

Kyle, Ken, can I request the spline count and compressed length of the ZZP F40 conversion axles once you get them, please?
 
KLMOTORSPORTS

KLMOTORSPORTS

Well-Known Member
Desert Sasqwatch said:
Go check out the latest post from Adam for the DoyleFab video reworking some axles. The disassembly of the transmission side looks straight forward and gives me confidence the Regal GS Turbo F40 axle ends can be installed onto the Cobalt SS axles.

Kyle, Ken, can I request the spline count and compressed length of the ZZP F40 conversion axles once you get them, please?
Click to expand...
Yep, you bet
 
Desert Sasqwatch

Desert Sasqwatch

Goblin Guru
Pulled the trigger and made a deal on the Quaife LSD for my F40 and got it ordered - less than $1K delivered. I will have to get my LSD and check the fit to be 100% sure, but the F40 is a European design (Saab?) so it should work sourced from the UK. I worked with Tom at WG Motorparts, he was very helpful to determine which LSD works in the US spec F40 and get a good price shipped from the UK. I used eBay for the purchase and made all communications through the eBay site to arrange the purchase.
 
Desert Sasqwatch

Desert Sasqwatch

Goblin Guru
I've seen some discussion that the F40 transmission has 'steeper' gears and its mph to rpm range is too tall for the Goblin. For those who may be curious (as I was) in the differences between the F35 and F40 in gearing, I ran the comparison at 2500 rpm to 6500 rpm mph range for each gear, starting rpm at next gear when shifting at 6500 rpm and *cruise in top gear at 75 mph:

F35 - 4.05:1 ring & pinion ratio (MU3) with 25.0 inch diameter tires
1st - 14 mph to 35 mph range
Drop to 3380 rpm at 6500 rpm shift
2nd - 26 mph to 68 mph range
Drop to 4360 rpm at 6500 rpm shift
3rd - 39 mph to 101 mph range
Drop to 4900 rpm at 6500 rpm shift
4th - 52 mph to 134 mph range
Drop to 5110 rpm at 6500 rpm shift
5th - 66 mph to 171 mph range
*75 mph cruise in 5th gear is 2850 rpm

F40 - 3.76:1 ring & pinion ratio (MU9) with 25.0 diameter tires
1st - 13 mph to 33 mph range
Drop to 3380 rpm at 6500 rpm shift
2nd - 24 mph to 63 mph range
Drop to 4360 rpm at 6500 rpm shift
3rd - 36 mph to 94 mph range
Drop to 4980 rpm at 6500 rpm shift
4th - 47 mph to 122 mph range
Drop to 5260 rpm at 6500 rpm shift
5th - 58 mph to 151 mph range
Drop to 5430 rpm at 6500 rpm shift
6th - 70 mph to 181 mph range
*75 mph cruise in 6th gear is 2700 rpm

Based on the above comparison, the F35 and F40 are nearly identical in gearing - based on rpm drop at gear shift and useable speed range - in the first 3 gears. These are the important gears for racing and street driving. The remaining gears are shorter ratio in the F40 which will result in faster acceleration at higher speeds (long straight on road race course). Cruise in top gear at 75 mph is a more leisurely 2700 rpm in the F40, for those looking to use their Goblin as a (semi) daily driver.
 
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George

George

Goblin Guru
What about SADEV ST82-14 transaxle so you can tailor the rations to use the horse power correctly

Brad
 
KLMOTORSPORTS

KLMOTORSPORTS

Well-Known Member
Good data...I actually was curious as well, but going by just comparing the ratios blindly, they seemed to be pretty comparable...thx for posting the info!
 
Desert Sasqwatch

Desert Sasqwatch

Goblin Guru
I made my comparison to satisfy the discussion for the F35 being a superior transmission in the Goblin versus the F40 transmission. The data indicates there is no difference in the first 3 gears and the F40 is superior in the upper gears. Based on the 'affordability' of each trans mission, it becomes a matter of budget and availability.

I have not heard of the SADEV transaxle? Looked it up and it is a racing transaxle that costs more than the whole Goblin kit. I am curious why someone would put this trans into a Goblin and has the funds to do so? It has selectable ratios, make the analysis and determine what will work. This trans is definitely outside of most everyone's budget.
 
George

George

Goblin Guru
Now that is out there maybe some day some where a use we popup for an insanely low price.

Brad
 
Desert Sasqwatch

Desert Sasqwatch

Goblin Guru
I am passing along some information: WG Motorparts - the place I purchased my F40 LSD from - will have several new F40 Quaife LSDs available in late April/early May. If you are interested, go to their website and contact Tom, let him know that Tim Marks recommended this contact. He can help arrange a better deal on the LSD than buying direct from Quaife. Please feel free to contact me if any additional information is needed.
 
KLMOTORSPORTS

KLMOTORSPORTS

Well-Known Member
Lonny just sent me some pictures from the DF shop on the first mock-up of my F40 sitting in a frame. They are going to build a frame without the transmission mount and sit it in there and see what needs to be done. Looks promising to me and excited to see what they can do!

Thanks Lonny for all your help on this....much appreciated!!

Ken


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