Quaife (big LSD manufacturer) has a 6 speed close ratio gearkit available for SS, anyone have any feedback or experience with the product?

Seems like it would be the ultimate driveline:eek:

:welcome: to the best place for anything :hhr: I don't have any info on the six speed kit, but if someone on here has, they'll chime in I'm sure. If quaife makes it, I'm sure it's a quality kit, but expensive!

I know they were offering them at a pretty good price on www.cobaltss.net but i don't know if any one acutally jumped on it.

Quaife (big LSD manufacturer) has a 6 speed close ratio gearkit available for SS, anyone have any feedback or experience with the product?

Seems like it would be the ultimate driveline:eek:

I am not so sure that there is a lot of advantage to the 6 speed since the turbo motor has such a flat torque curve, but maybe I am missing something. Very expensive that's for sure.

http://www.chevyhhr.net/gallery/files/4/9/0/4/DynoChart.jpg

I know they were offering them at a pretty good price on www.cobaltss.net but i don't know if any one acutally jumped on it.

Don't see any more info on the Cobaltss.net forums, but I'll post up there and see if I can get some feedback:thumb:

While the Quaife gears would be great strength-wise, I fear the F35 case will still be a weak link as they tend to have cracking issues (from what I have read elsewhere, not personal experience). Now, if the case cracking issues can be attributed to shaft flex, etc that the stronger Quaife unit corrects, this could be a great, although expensive, mod.

I have no intentions of leaving my HHR SS in stock form as this 2.0 Ecotec is a strong engine. The gearbox scares me though.

While the Quaife gears would be great strength-wise, I fear the F35 case will still be a weak link as they tend to have cracking issues (from what I have read elsewhere, not personal experience). Now, if the case cracking issues can be attributed to shaft flex, etc that the stronger Quaife unit corrects, this could be a great, although expensive, mod.

I have no intentions of leaving my HHR SS in stock form as this 2.0 Ecotec is a strong engine. The gearbox scares me though.

A 6 speed would likely lose acceleration due to the broad torque curve of the LNF with VVT.

As far a "The gearbox scares me....", so it does GM! :eek: That's why they incorporated "launch control" and "no lift shift", which are nothing more that nanny controls to prevent abuse and subsequent warranty claims.

No, I think you've got that wrong. Seems to me that if you wanted maximum acceleration capability, especially with the broad, flat torque curve of our motors, then this gear kit would certainly be the way to go. With the same torque, but better gearing, you will pull harder, and acclerate faster. And yes, the Quaife kit is undoubtedly stronger.

Where have people been breaking their cases?

Very expensive that's for sure.

It's all relative, I suppose, but I actually saw this kit advertised for only $3399.99 from Turbo Tech racing: http://www.turbotechracing.com/productcart/pc/viewPrd.asp?idcategory=5615&idproduct=5076

And that they are apparently working on a package deal that will include the installation into a supplied gearbox. That would be SWEET! :smile:

For all of the benefits: speed, strength, fuel economy, cool factor... it seems like a reasonable mod.

Where have people been breaking their cases?

There's several threads over on the Cobalt SS forums with discussions about the F35 and F40 gearboxes. Several discussions regarding the F35 cases cracking (and apparently at the same location). Sent some messages trying to get more info

There's several threads over on the Cobalt SS forums with discussions about the F35 and F40 gearboxes. Several discussions regarding the F35 cases cracking (and apparently at the same location). Sent some messages trying to get more info

I see on the http://media.gm.com/us/powertrain/en/product_services/2008/08car.htm site that the F40 six speed is used on Saab 2.0L combinations, I didn't think the 4 cylinder block bolt pattern was the same as the V6 pattern that this transaxle is used on? :confused: I've got an F40 here at home that I'm using for a 3.1L V6 in a Beretta. Maybe GM didn't use this six speed in the SS because it requires an intermediate shaft & equal length axles, requiring mods to the HHR engine cradle/suspension? :confused:

From what I understand, it is no easy task to swap in the F40. It has a different bolt pattern on the bell housing, different axles, and a different shift mechanism. No thanks. I'm still very interested in the Quaife six speed conversion for the F35. If only I knew why the cases were breaking....

I wonder if the Quaife conversion makes the tranny stronger by reason of the two extra bearings that support the ends of the shafts outside of sixth gear? I'll bet that makes a difference, and limits shaft flex.

From this specification it looks like a stock SS is right at the torque rating of the F35. Probably conservative, still....I wonder how much more we can safely boost the power: http://www.gminsidenews.com/index.php?page=trans_guide

A 6 speed would likely lose acceleration due to the broad torque curve of the LNF with VVT.

As far a "The gearbox scares me....", so it does GM! :eek: That's why they incorporated "launch control" and "no lift shift", which are nothing more that nanny controls to prevent abuse and subsequent warranty claims.
I swear just a few months ago I read where Chevy tried the SS with a 6 spd gear box and it slow the car down. Thats why they opted for the 5 spd. I can see that with a turbo car.

From what I understand, it is no easy task to swap in the F40. It has a different bolt pattern on the bell housing, different axles, and a different shift mechanism. No thanks. I'm still very interested in the Quaife six speed conversion for the F35. If only I knew why the cases were breaking....


I wonder if it's because of the solid motor and trans mounts people are installing to "get robbed power back"...

F35 will probably take a lot more power and abuse than it's rated for. Just have to be smart in how you use it.

So now that I have lived with the SS for almost 20,000 miles, I really can see that the 6 speed would be a very nice upgrade. First gets taller (3.00) vs 3.38 stock, which is good since 1st seems too short in most folks opinion I believe, 2nd and 3rd are shorter than stock which means 3rd would be very useful for tight back roads where I find 3rd a bit too tall. Third gear pull with the tune (GM or Hahn/PPC) would be even better than it is now (which is fantastic)! Now slight problem is still almost $4,000. to do this swap.

Now slight problem is still almost $4,000. to do this swap.

I recall reading a snippet on one of the Cobalt boards that you lose reverse. I tried to contact Quaife via email for clarification but never got a response.

I recall reading a snippet on one of the Cobalt boards that you lose reverse. I tried to contact Quaife via email for clarification but never got a response.
Hmm, now that would be a problem :smile: .

Hmm, now that would be a problem :smile: .

OK, maybe not. I was surfing my way to their site again to send them another query on the subject when I found the following on cobaltss.net...

5-Speed FGP F35 Transmission using Quaife's 6-Speed conversion:

Type: Transverse front wheel drive, five-speed manual transaxle ( Optional with limited slip differential )
Engine range: 2.0L I-4 supercharged
Maximum engine torque: 200 lb-ft ( 271 Nm)
Maximum gearbox torque: 258 lb-ft ( 350 Nm )
Wheel+Tire Circumference: 2044mm
Gear ratios: MU3
First: 2.72
Second: 1.89
Third: 1.368
Fourth: 1.045
Fifth: 0.833
Sixth: 0.704
Reverse: 3.17
Final Drive Ratio: 4.04

So... never mind :red:

Yup..looks like a good trans for a closed course....no real benefit on the street other then bragging rights and having to shift more. The main reason for more gears is to maintain torque peak,something not lacking in this little motor.

Worthless mod for a show car. Second doesn't need to be shorter, as I spin through most of it as is. With a little more power, third will be the same way.

OK, maybe not. I was surfing my way to their site again to send them another query on the subject when I found the following on cobaltss.net...

5-Speed FGP F35 Transmission using Quaife's 6-Speed conversion:

Type: Transverse front wheel drive, five-speed manual transaxle ( Optional with limited slip differential )
Engine range: 2.0L I-4 supercharged
Maximum engine torque: 200 lb-ft ( 271 Nm)
Maximum gearbox torque: 258 lb-ft ( 350 Nm )
Wheel+Tire Circumference: 2044mm
Gear ratios: MU3
First: 2.72
Second: 1.89
Third: 1.368
Fourth: 1.045
Fifth: 0.833
Sixth: 0.704
Reverse: 3.17
Final Drive Ratio: 4.04

So... never mind :red:
These ratios seem to be different, wonder what the actual specs are. http://www.turbotechracing.com/productcart/pc/viewPrd.asp?idcategory=5615&idproduct=5076

Worthless mod for a show car. Second doesn't need to be shorter, as I spin through most of it as is. With a little more power, third will be the same way.
Tough to say, third gear tops out before the end of the 1/4, so would times be faster with closer ratios and the same number of shifts? A lot of experiments with 3 gears to 7 with 4-stroke MX bikes and also cars, seems like in general 6 speeds has been where most perf vehicles end up turbo or otherwise.

Tough to say, third gear tops out before the end of the 1/4, so would times be faster with closer ratios and the same number of shifts? A lot of experiments with 3 gears to 7 with 4-stroke MX bikes and also cars, seems like in general 6 speeds has been where most perf vehicles end up turbo or otherwise.


Thats why we can up the rev limit 200 to 400 rpms more and still be in 3rd going through the traps. ;)

No, I think you've got that wrong. Seems to me that if you wanted maximum acceleration capability, especially with the broad, flat torque curve of our motors, then this gear kit would certainly be the way to go. With the same torque, but better gearing, you will pull harder, and acclerate faster. And yes, the Quaife kit is undoubtedly stronger.

Where have people been breaking their cases?

I cracked mine wide open @ 7200 miles With just DR's on.

I cracked mine wide open @ 7200 miles With just DR's on.

Hi unclesams,

Would you elaborate on the circumstances, or give any knowledge that you have with "cracked cases"?. I'm sure many here would like to know.
Thanks.

its possible to do but very exspensive...you would have to change the final drive ratio too or your gears would be extremly short. Now the only reason this would be of use is gas mileage ,it would drop your rpm lower at higher speeds... not really help your performance at all except add a extra gear change which would probaly slow you down.

When these cars were being tested the engineer form gm said that the cars were slower with a 6 speed so this a expsensive mod with very little gain. I can find the ;inl on the cobalt forums if needed.

Tough to say, third gear tops out before the end of the 1/4, so would times be faster with closer ratios and the same number of shifts? A lot of experiments with 3 gears to 7 with 4-stroke MX bikes and also cars, seems like in general 6 speeds has been where most perf vehicles end up turbo or otherwise.

Thats why we can up the rev limit 200 to 400 rpms more and still be in 3rd going through the traps. ;)

Exactly. Get HP Tuners and that won't be an issue.

With that said, I'd like to revise my statement.

It's a worthless mod for show cars IF YOU REMAIN ON STOCK TURBO.

If you were running a big, laggy turbo, say a GT35 (journal bearing), I could see the benefit.

Thats why we can up the rev limit 200 to 400 rpms more and still be in 3rd going through the traps. ;)
I have the HPTuners and the Hahn/PPC tune, but I was talked out of raising the rpm limit in 3rd gear by someone with more experience than me with these drivelines due to possible durability considerations with 3rd gear and high rpm/horsepower. If I was actually competing for best 1/4 mile time I would definitely do it though as that last shift definitely costs time (although I don't think 400 rpm would be enough to avoid the shift). As far as the 6 speed, the cost/possible_benefit is not there for me or most folks.

anyone bite the bullet yet on this kit?

anyone bite the bullet yet on this kit?

We have sold about 5 of these kits, 2 have went to Canada, and the other 3 to USA customers...

They have all been in the cobalt, which the HHR is the same with the F35 trans.

We have sold about 5 of these kits, 2 have went to Canada, and the other 3 to USA customers...

They have all been in the cobalt, which the HHR is the same with the F35 trans.
And what is the feedback from owners, and how are the cars used? (Daily Drivers, Quarter Mile, Track days, SCCA)?

Exactly. Get HP Tuners and that won't be an issue.

With that said, I'd like to revise my statement.

It's a worthless mod for show cars IF YOU REMAIN ON STOCK TURBO.

If you were running a big, laggy turbo, say a GT35 (journal bearing), I could see the benefit.

I agree 100% with this statment. When you're running a fast spooling turbo like the factory one in the SS, having shorter gears will give you the illusion your vehicle is quicker given how fast the turbo/motor spools out, but realistically with a little taller gears in succession from 1st to 4th with the F35 trans, it will provide much smoother and more reliable acceleration. GM did in fact do a study with this, I dont remember nor can I find the article to show you guys unfortunately, so I'll leave that as speculation for now, but they found the same issues as I pointed out that the smaller turbo is just too responsive to have access gearing. Not to mention your fuel economy will suffer. Having the shorter gear ratio in city driving will do some damage.

NOW, if you were going to use a lag prone turbo set up like aaronSS had mentioned, then a closer range of gearing is ideal to keep your RPM's and boost pressure in the power band between gear sets.

And what is the feedback from owners, and how are the cars used? (Daily Drivers, Quarter Mile, Track days, SCCA)?

Awesome feed back, and most are drag or track, which all are daily drivers.

Hi unclesams,

Would you elaborate on the circumstances, or give any knowledge that you have with "cracked cases"?. I'm sure many here would like to know.
Thanks.

Under hard acceleration I shifted between 2nd to 3rd and heard a loud boom. When I looked under the car I could see a crack all the way around the bottom of my transmission, and all of the fluid started leaking out all over the ground.