getrag 5 speed mods (Page 2/3)
cartercarbaficionado JUN 16, 04:14 PM

quote
Originally posted by Frenchrafe:

Yes, even here in France we can find F23s and F40s second hand for about 250€ to 350€.
Alot of them come out of Saabs and Opels. Does anyone know if they have the same bellhousing pattern?
This one for exemple is only 115€ on Ebay france:


Seems like the starter motor fixing is totally different?



that Is not the gm 90/60 degree fwd bellhousing pattern. also the starter is still bolted to the engine for all but I think 1 of the engines in the family
Frenchrafe JUN 17, 05:29 AM
Yes, thanks.
I did some searching afterwards and I have some of the vehicle models to look for:
- 2006-2007 Pontiac G6 with the 3900 engine (F40)
- 2000-2002 Cavalier 2.2L (F23)

Of course there aren't any in Europe!

------------------
"Turbo Slug" - '87 Fiero GT. 3800 turbo. - The fastest Fiero in France! @turboslugfiero
https://youtu.be/hUzOAeyWLfM

Raydar JUN 20, 11:34 AM

quote
Originally posted by Frenchrafe:

Yes, thanks.
I did some searching afterwards and I have some of the vehicle models to look for:
- 2006-2007 Pontiac G6 with the 3900 engine (F40)
- 2000-2002 Cavalier 2.2L (F23)

Of course there aren't any in Europe!





Are there no equivalent manual trans applications that used the 60 degree pushrod V6? I'm guessing Opel or Vauxhall.
(Edit - Just discovered that Vauxhall is now owned by Stellantis? Wow...)

[This message has been edited by Raydar (edited 06-20-2024).]

cartercarbaficionado JUN 20, 09:01 PM

quote
Originally posted by Raydar:


Are there no equivalent manual trans applications that used the 60 degree pushrod V6? I'm guessing Opel or Vauxhall.
(Edit - Just discovered that Vauxhall is now owned by Stellantis? Wow...)



there's really not many different manuals for the 60 degree fwd bell housing pattern. there's almost twice as many automatics which is unfortunate
Yellow-88 JUN 22, 11:40 AM
The basic rule in mechanical design is to do the physics math and then at least triple the result number. Something similar has been done on all the gearboxes being discussed hear. Yes, very dramatically increasing HP and or torque and you do need to consider a different gearbox, or a race prepared one. Sheet metal add on's are not the same.

Interestingly, Yellow uses the Isuzu 5 speed with the stock 2.8 V6 and I've never worried about breaking it no matter how robustly I drive. The torque or HP available from that engine is not enough to do that, unless one adds IMPACT forces to it. Dumping the clutch from red line or banging gear changes can push the limits of the design.

I learned early that you can break anything if you're not careful . Those who have become famous in the motorsports world know that all too well.

I think that the typical big block tire smoker muscle car driver would completely break a championship Lotus ...... and may logically consider it wimpy. Light weight mid engine sports car people are naturally different animals. I hope.
cartercarbaficionado JUN 22, 06:46 PM

quote
Originally posted by Yellow-88:

The basic rule in mechanical design is to do the physics math and then at least triple the result number. Something similar has been done on all the gearboxes being discussed hear. Yes, very dramatically increasing HP and or torque and you do need to consider a different gearbox, or a race prepared one. Sheet metal add on's are not the same.

Interestingly, Yellow uses the Isuzu 5 speed with the stock 2.8 V6 and I've never worried about breaking it no matter how robustly I drive. The torque or HP available from that engine is not enough to do that, unless one adds IMPACT forces to it. Dumping the clutch from red line or banging gear changes can push the limits of the design.

I learned early that you can break anything if you're not careful . Those who have become famous in the motorsports world know that all too well.

I think that the typical big block tire smoker muscle car driver would completely break a championship Lotus ...... and may logically consider it wimpy. Light weight mid engine sports car people are naturally different animals. I hope.


yeah I would probably do alot of those *ahem* dumbass maneuvers so your right about th sheet metal not helping but I don't think quarter inch plate is sheet steel anymore (my 69 toronado begs to differ lol) really I'm probably just putting off having to go find an f40 and doing the conversion to have a 6 speed instead which for me would be nicer especially since I could have a much lower first gear for when I drive up to Seattle and have to deal with people creeping up to my bumper everyday
Yellow-88 JUN 24, 10:08 AM
I think that if I did any gearbox mods, I'd start with a hydraulic release bearing. Long levers and push rods just seem old technology. The other would be a less sloppy gear shift system. The cables are fine but the linkage is sloppy and crude. Full size, serious rod ends may be all that's needed. Modern gearboxes have a swinging counter weight on the gear box end of the linkage that seems to help the "feel". That might be something to consider.
cartercarbaficionado JUN 24, 11:31 PM

quote
Originally posted by Yellow-88:

I think that if I did any gearbox mods, I'd start with a hydraulic release bearing. Long levers and push rods just seem old technology. The other would be a less sloppy gear shift system. The cables are fine but the linkage is sloppy and crude. Full size, serious rod ends may be all that's needed. Modern gearboxes have a swinging counter weight on the gear box end of the linkage that seems to help the "feel". That might be something to consider.


oh yeah that would definitely be the way to go but the linkage isn't that bad on these honestly. a decently taken care of fiero doesn't feel like I'm rowing a boat like the mk1.5 focus (has that counterweight you mentioned) or the 2013 v6 6 speed mustang which was incredibly notchy and grindy feeling. it would also skip the teeth of the syncros together at 5k and above meaning you had to double clutch.
I have some ideas on how to make the fiero better but I need to start prototyping them to really throw together a short shifter (a practical one that isn't just for racing use or a modified 84 4 speed unit) and allow the transmissions to have a faster acting syncro that can allow for much smoother and quicker shifts. that one is the big deal I'm still working on modeling and prototyping for my getrag since I don't have a spare 4 speed to rip apart (I do but I know every bolt is gonna snap on the 84 sport 4 speed I have since it came out of a car that was partially submerged when I saw the thing) I have some ideas for some better dog style syncros but the issue with those is material. like I can make it out of ductile hard chromoly that's only really hard on the wear surfaces to prevent a brittle failure once they slam and lock together but then wear is an issue unless I redirect oil onto them constantly which is inefficient and could compromise the lubricant quicker. or I could use a carbon fiber clutch to help bring them to a closer speed quicker but wear becomes an issue again. an asbestos alloyed material would allow for a stronger more aggressive style of clutch but would have the very obvious issue of having asbestos
I've been prototyping with a 2 horse lathe and a drill press to mimic road speed and the engine speed to make long lasting fast syncros but so far the best I've done has been a modified honda style with a brake pad clutch and a large teeth lead in to help the speed. it performed wonderfully but broke and wore very quickly when pushed to higher revs and more aggressive shifting
Craig71188 JUN 25, 07:27 AM
Muncie 4 speed (85+ case) was used in the GTU IMSA Fiero's with Webster made straight cut gears to convert it to a dog box. Lots of gear ratios were available given the disadvantage to the other cars in the class running 5 speeds. They were durable enough to handle 300+ HP through 12" slicks. Had my first experience with mine a week ago - shifts great on track!
cartercarbaficionado JUN 25, 08:15 AM

quote
Originally posted by Craig71188:

Muncie 4 speed (85+ case) was used in the GTU IMSA Fiero's with Webster made straight cut gears to convert it to a dog box. Lots of gear ratios were available given the disadvantage to the other cars in the class running 5 speeds. They were durable enough to handle 300+ HP through 12" slicks. Had my first experience with mine a week ago - shifts great on track!


unfortunately the only case I have is an 84 which I've been told is like a cracked glass bottle in strength. does sound like some mods oll look into