Variations in 308 Transmissions

Hi

Can anyone educate me as to the variations in 308 transmissions,
eg fitting, gears, syncro etc...

As I am trying to source a spare unit, and obviously don't want to buy the wrong variant.



thanks.

 

What year/model/version 308 are you trying to match?

 

Great timing for this post question for me.

This past Friday I drove a friend's 85 US model to Atlanta. I couldn't believe how high it was geared in 5th compared to mine. At an "indicated" 80mph it was running right at 2450 rpm. My 84 is probably 3800 or so at the same speed (just a guess)

After I got home I remembered the tires.... It has stock wheels but I would be really surprised if the tires were stock sizes (Mine are factory spec). I can find out in a little while and I will post the size

But how much of a difference could that make or are the transmissions geared differently between 84 and 85?

I am really curious.

 

No difference that I'm aware of between '84 US 308QV and '85 US 308QV gear ratios, but a euro 308QV is quite a bit taller gear-wise -- if your friend's car is a euro... (in addition to any tire size effects).

 

I know my speedo and a few others I have seen are a bit optomistic in their reporting but good part is that it improved my 0-60 times. The change you observed would similar to changing the rear drive almost a 1:0 ratio taller in the 85. 3800 @ a gps reported 80 is similar to where I am at in my 82. You could be right on the tires but they would have to be signifigantly taller to make that much difference. I have also read the the QV's had a slightly lower ratio to improve accelleration and if I can find the article on that I will post it.

 

It's not. Just a regular USA model. Sold new in California 20 May 1985.

Something is really weird here because the difference is striking on the highway. I have 15 years and 60,000 miles of seat time in my 84 and I couldn't believe the difference. What actually cought my attention was the needle position. My tach needle and speedometer needle are almost exactly in the same position on the highway but his tach needle was way lower.

 

Bad tach ? About the only cars I know that run 2400 rpm at 80 are diesels!

 

+1

Your ~3800 RPM for 80 MPH is in the right ballpark for a US 308QV. Unless your friend has monster truck tires, the tach must be off

 

That's what it was too. 2450 (just a tick under 2500) at an indicated 80 mph.

Also, I really was driving about 80. I know about speedometer error and all but I was driving along at my normal comfortable speed when I noticed this. What I mean is I know I wasn't driving 50 mph and it was just a funny acting speedometer.

 

Could be a different set of transfer gears?

 

According to Willoughby's book the Qv had a final drive ratio of 3.82 whereas the previous injected cars where 4.06 With the 328 the gear ratios remained the same but the crown wheel and pinion changed from 17/65 to 17/63. If that helps.

 

I'll have to dig it up, I put together a xcell file a couple yrs ago with all the variants of gearing. There is a few over the yrs and markets.

 

My 84 is at least 3800 indicated at 80mph. I just drove 550 miles on I-95 last week and it seemed to be running a little above 4K at 80. Maybe my tach is reading a little high..

 

Back to the task at hand

 

My car is a race car, so not so easy to say 'year of production' and all that.

I need to learn about the variations and how to identify them, so that i can determine what is currently hanging off the bottom of the engine and then go looking for a spare.

So most keen to know/get info...

1. spreadsheet of ratios

2. Any physical variations, like '84 won't fit a '78 because....

3. Ratio varitions in transfer gears / final diff gears

4. Upgrades, eg convert syncro to dog engagment, straight cut gears etc....



thanks

 

The only sets of Xfer gears you can get that change things tend to make the gearing shorter - which is fine if you want the thing for track use & to top out at 130.

I looked into this a while ago in the hope of finding a gearset that would add maybe 5-10% more legs to the 328 & there is nothing that would do it.

(Have since abandoned the idea having put a standard exhaust back on the car & found it cruises quietly enough if you keep the engine just off the cam & also driven it in the mountains where the gearing all makes sense).

Tommy's talking about a gearing that looks like its 30+% longer - never do that with Xfer gears or even a combination of Xfer gears & a diff & tyres even!

Bad tach I think.

 

Page E7 in the 550/89 308QV/328 WSM is a good reference for those models -- although you have to be careful about understanding their calculated ratios. The tooth counts are OK, but:

1. the table on the left side = the gear set ratio inside the gearbox only

2. the table in the middle = transfer gear ratio X gearbox ratio (no diff ratio included)

3. table on the right side = gearbox ratio x diff ratio (no transfer gear ratio included)

Surprisingly, they never give the whole thing (gearbox ratio X transfer gear ratio X diff ratio)

The OMs also have the same sort of data in Section 1 (but it applies only to the model/year/version that the OM covers).

This WSM and the OMs can be downloaded from here:

http://www.ferraridatabase.com/The_Downloads/Downloads.htm

I believe on 328, another bearing was added to support the outboard end of the gearbox input shaft and the clutch shaft -- obviously requires a different gearbox input shaft, different clutch shaft, and transfer gear housing. Not sure that they can be mixed-and-matched, but, if you plan on serious thrashing, having these extra bearings might be a good thing. There are other small changes (like 2 different clutch shafts on 308QV that mount different gears) so you'll need to do a lot of SPC study IMO.

There are some aftermarket transfer gear set-ups available:

Image Unavailable, Please Login

Image Unavailable, Please Login

but cubic $s required

Please let us know what you learn...

 

Straight cut & noisy!

....and well north of $5K a set ISTR

 

True for the bottom set, but the top set is helical -- probably even more $!

 

My application is Race only, so the more noise the better.

I can see a long and steep learning curve before me - once again.

Attached is a pic of the engine.

So over the coming months we have to put gearbox on it's naked bottom,
but one thats up to the task of handling 420bhp, although I don't think I have the guts to rev it to 9k, so 8k will do fine.

So what companies offer aftermarket transfer cases and other assorted goodies ?
Image Unavailable, Please Login

 

Nice intake setup. The stock gearbox will handle 420Hp, I've pushed over 500Hp thru them. The clutch is whole 'nother thing. a multidisk tilton, quatermaster etc.. style is for the moment your best bet.

I need to get that gear ratio file up. I think I posted it once before yrs ago, but the 'fantastic' search function here will take longer then me plugging in the 'ol back up drive.

 

Yep, I recall having to sort thru and calculate the ratios. I have found the file and it's messy due to this problem. I have a variety of columns and 3 for gear, idle and final. these then are used against an RPM for a final MPH. Looks like I even spent some time doing Tq calcs too, don't recall finishing that though and the sheet bears that out.

there is a Base, US and CH or Swiss, versions and also the same for the Mondial that has the added internal oil pump not found on the 3x8's. So there are 8 basic variations not counting the iterations one could make combing those 8. the differences are in the gears in the box, not idle or diff.

The file is far to messy to post up, sorry. I'll see If I've got free time in the next week or so to clean it up.

 

What? You expected something different?

Modena Engineering (in Australia?) is my vague recollection of one supplier of the aftermarket transfer gear stuff.

 

Steve, in your last post with 2 pictures, one shows helical gears the other straight.

Can you elaborate some more on this.

 

So lets start wit the base enclosure for the transmission, the part that bolts up to the engine.

Did this vary across 308 models?

Where there different sizes, bolt patterns. Long or short this and that?