The Cal-look Lounge

Hi Guys
I need a built swing axle box for my 72 beetle (and short axles!).
82x94
Ported 42x37 heads
FK10 adv 4º
10.2:1 (0.040" deck/ 50cc chambers/ 5cc dish)
1 5/8" sidewinder
36mm throttle bodies
EFI with crank trigger ignition

Not sure what power it's making, like to think around the 170BHP mark
Full weight car
205/60/15 street tyre

Not planning on drag racing although the odd RWYB may be on the cards
I want to cruise around and not need earplugs though

Currently running the stock 1300 box.
I think dropping from a 4.375 to a 3.875 R&P would do what I want but after extensive googling I know some gearsets are stronger than others. Need welded 3+4 etc

Super diff on the street? Seen some reports of them wearing badly.


Also, if anyone knows of any, or can recommend a good builder in the UK let me know

Look forward to hearing your thoughts :)

Hi Luke,

When my oval was first built I had a Cogbox built box. It was nowhere near a drag spec box but I got it second hand (although had never been used) and it was all I could afford at the time. It came with the spec on a card from Pete and it was a 4.12 r+p,  welded 1.48 3rd and 1.04 4th. It also had steel shift forks, superdiff and super beetle 1st.

It was such a nice box on the street, the 4th was a bit too tall for 1/4 mile as you could hear the revs drop a bit too much when racing. Alex Taylor@ Defcon 3 drove the oval and he said it was so smooth considering it would run 11.9 1/4's.

I still have the box, it needs a repair as something broke during a burnout with slicks. Pete used to call it the miracle box as it lasted a long time with slicks, 1.5 60 foots and probably a little over 200bhp.

Hope that helps.
Lee

Evening Lee.

I probably don't have the engine do push those kinda ratios then if yours struggled to pull 4th, that said, I'd happily lose 5/10ths in the 1/4 if it meant for a happier road car.

I've see Pete @cogbox mentioned many times, bears Motorsport, and John Walklett are all on my list. I'd much rather go that route than to buy a Rancho.
But I guess it's largely price dependant.

Was you on similar sized rear tyres?

I guess you could go to a 1.14 4th? But Pete is obviously a better person to take advice from than me  ;D

My tyres were 185/70 or M&h Slicks.

Things that can be good to know before
As the weight of the car What height of tires to use
Then to dyno drive machine (Why it To know what the maximum torque was where the next gear ends up)
It is very difficult to just say that you should use that type of gear if you do not have that info if you want to drive fast
I usually ask that as the first question if I should build a box
And how fast you want to drive
If you want to drive very fast Type 10a which is low or high, there is a lot of difference in gear
An example wants a 60 f on a low 1.35- 40 R&P 4.12 (nr1) 3.78 gears at 8000 rpm (nr 2) 2.25 8000 + rpm (nr3) 1.58 8000+ rpm (nr4 1.32 8200+ rpm This with 26 "tires and you should be down to 10.35 or lower with a car that weighs 750kg If you change to 3.78 in R&P you will have even more power in the machine to get a good 60 foot
But if you want a daily driver like that and you are happy with a mid 13
3.78 (I prefer 4.12) Nr1 std Nr2 std Nr 3 1.48 Nr4 1.13 super diff reinforced side end With (2165 40x35 ida) 150hp (137whp) regular 25.5 high tires, I am on 13.8-14 with my daily driver (stereo and such as you need when driving

Similar sidewall height tbf.
I guess it wouldn't hurt to get in touch with Pete.

Cheers.

I don't know the power of the car yet.
Still tweaking and tuning the maps and of course various covid restrictions mean a Dyno session is off the cards.

24.7" tyre diameter.

Cruising at 100-120kph is the norm in the UK.
Weight, idk, stock 72, full interior, no cage.

With this information that you have, it is very difficult to build a good box
If we take the tire difference from 24.7 tires to slicks 26 "it is difficult to build a box with that difference
With 24.7, you need 0.89 on four gears
Slicks 1.14 if you want to crusade in 100-120 to keep the engine speed ok
If there are no truck scales in England, you can check what the car weighs
/// M

We have a weighbridge where I work.

Slicks aren't on the cards, I won't be swapping to drag tyres. If it sees any drag action it'll be on the street tyres I drive there (and hopefully home!) On :D

I have a spreadsheet somewhere, pm me if you want it. I went for a 3.44 R&P, super Beetle first, then evenly spaced ratios thereafter, until 4 is roughly where VW put it, but it's too tall for racing, great for a street car capable of going on longer runs and still fun. To race this combo you would need more power than I have, ported, balanced 1956, or a 3.88.

https://weddleindustries.com/gear-calculator


Use this. Good calculator

Thanks guys.

I'll have a play around with the calculators.

Where is a car happy cruising at 70mph/120kph? 3000 rpm? 3500rpm? I know it's rather engine specific, the efi gives me brilliant low rpm driveability that is sometimes missing with Ida's though :)

My car runs a stock 1972 1300 ratio gearbox, and I've added a superdiff, heavy duty sideplate and short axles. It's full weight, street tyres and I reckon around 160bhp - it ran 14.4 @ 93mph in this car and 12.50 @ 108ish in my old race car on slicks with a close ratio box. I expect it to go 13s at 100+ with seat time, but the stock ratios do make it quite nice to drive on the road. Couldn't tell you what rpm it's doing - I really should get a rev counter!

That sounds interesting

How is it holding up? I thought the 3+4 gears were meant to be pretty weak? Just press fit?

That could be a cheaper alternative, have mine rebuilt to that spec, with a 3.88 r&p in it. That would bring cruise rpm down nice

Is that a bad idea?

Is that a bad idea
There are no bad ideas
If you want a good street box it can be a good idea
But if you want to run a good time on the strip
Maybe it's not such a good idea
Would think it is next the same cost to modify a box with other gears of 3-4 as to build a new one
It is a lot of work to build because you have to measure a lot
It's not just changing gears as many people think in a VW box
Because if it is a 3.88 and the old type of gear then you have to modify the shaft before you can put the gears there
If you change to the Hd side plates, you must measure R&P

I have a 67 with a 2.2 liter motor.  It has a 4.12 with the stock 3.78,2.06,1.26, .89 gears in it.  I drove it with 205-70 tires and put 26” slicks on it for the strip.  I haven’t been able to run the 1/4 in it yet, just 1/8 stuff.  It’s 1775lbs and runs 7.40s-.50s.  The stock gears are good for street and highway and I should be able to do 111mph in the 1/4 still in 3rd gear.  I had closer gears in it but hated it on the street/highway sand took them out.   Super diff, welded 3rd and 4th, chromoly retainer, super beetle mainshaft, sway a way axles.

My original 1/4 mile race box was setup so that 6000+rpm was flat out at the end of the strip at close to 95 to 100mph, trouble is, on the highway that equated to 70mph and approx 4500rpm, it was noisy and thirsty. I can't recall exactly but the rpm has dropped by at least 1000 at the same speed, I can't now see this ratio working that well on the strip, however; it's very hard to cover both jobs with the same box.

Stock 1300 gearing with a 3.88?
Super beetle main shaft
Course tooth 3 and 4 with welded hubs
Super diff
Hd sideplate
 
Would that play nice on the street, take lots of abuse and the odd run up the strip?

stock 1300 gearing and 1600 are about very similar with the slight diff on 3rd and 4th, but if you are going course tooth means they will be changed out anyway.

i am not a fan of super diff, since this is a complete dissassembly, i would save hard for a quaife or the GT atb or LSD, yes they cost quite a lot more

i would use either a rebuilt/rebushed gear carrier or a new aluminium gear carrier, HD thrust plate and a rebuilt nosecone.

also steel shift forks, new single roller bearings from Weddle

Driving my white swing axel 68 (specs below) now with the Rancho with 3.88 RP and stock ratios I find the engine revving still too high while cruising and considering changing to a 3.44 RP.
It's not ridiculous, but feels better at around 100kph so I end up doing that in the right lane with occasional faster sections. The trouble is that now the govt has raised the limit by 10kph and everyone has upped their speed, including the big trucks so they want to overtake me as well.
I could drive it faster, but the vibrations increase which damage parts over time (I had an aluminum bracket break from fatigue) and seems unnecessary with the kind of power to weight we both have with these cars.
I suppose the real answer is a Berg 5 where you can "have it all".

btw, what is the reason behind the Rancho hate I see everywhere? Are they famous for failing early, or making noise, or bad service, just curious as mine has been fine and works as advertised.

Sorry to pick on you Luke, but here goes my rant.
There is no such thing as a "Super Beetle" main shaft.  There are two main shafts.  Early 10 tooth first, and later splined 9 tooth first gear.  A 71 and 72 1302 Super Beetle got the early 10 tooth first. It did NOT get the so-called "Super Beetle" main shaft.  Standard Beetles, Karmann Ghias, and Type 181s after 1973 got the stronger 9 tooth first gear. Same for the 1303.  Given that, which main shaft is a "Super Beetle" main shaft?
If you think this is all semantics, it's not.  A local guy came to me wanting me to build him a strong gearbox for his street car that he could thrash at the drag strip from time to time. He sent me a photo of his stock core with its trans number. I recommended upgrading to the 9 tooth main shaft (more $$). I never heard from him. Then later I found out he was trash talking about how I tried to rip him off by charging him extra for the 9 tooth main shaft when he knew for a fact that his core gearbox came from a 71 Super Beetle, so it had to have the "Super Beetle" main shaft in it.


"Super beetle main shaft
Course tooth 3 and 4 with welded hubs"

Whenever you see a trans builder offer this, walk away. IMO this is the dumb way to build a trans.  When you talk about welding the synchro cones to the gears, that means early 113 gears.  Those gears require you to use the early keyed main shaft, which only comes in a 10 tooth first gear.  To get the stronger 9 tooth first, the main shaft has to have the splines for the late 3-4 hub turned down, then a keyway cut so you can use a woodruff key. Then you can press on the keyed 3-4 hub and use the early gears.
The better way is to simply get stock Bus 002 3rd and 4th coarse tooth gears from a 72 or later Bus trans. Then just assemble them onto the stock 9 tooth main shaft using the splined 3-4 hub as if it was a stock build.  The Bus gears have their synchro cones welded on by VW using a tiny electron beam welder. The weld goes all the way around, and causes no distortion like what happens when the trans builder TIG welds 113 gears.

Sorry to flog a dead horse here guys but I've just dropped my box off with John Walklett..

I'm torn between
3.88 r&p, 3.78 1st, 2.06 2nd, 1.44 3rd and 1.04 4th.
4.125 r&p, 3.78 1st, 2.06 2nd, 1.32 3rd and 0.93 4th.

I guess the 4.125 option will use fewer aftermarket parts and thus be cheaper but I don't know if I need the extra strength of the 3.88 build.
Also, is a 3.88/1.04 on the street useabale day to day?

That with gearboxes and gears
4.125 is so strong that you can not understand how strong it is
With about 300 hp we have driven 50 turns down the strip (1.40-42 60f)
99 cases out of 100 when you kill a box it is the clutch that does not work 99% of the cases it is too hard pressure plate so it locks so hard and the gears break into pieces
On the strip, you want the clutch to slip a little at the start
If it does, the box will hold together for a long time
/// M

If you're not using slicks, the strength of the R&P is not a concern. You won't be able to break either.

Only you can answer that.

According to the calc, 3.88/1.04 your engine will be spinning 3800 rpm at 70 mph.
With my big engine, and stock .89 fourth gear (3.88RP) it's doing around 3200 rpm.
Still pretty loud and buzzy so I usually avoid cruising that fast and like to keep it around 3000 rpm max.
It just doesn't seem worth the risk to vibrate the motor that much continuously.