Please help me design a gearbox to match my 2276 engine

[1961bluebug]

Finally due to money and time issues I purchased and ran Pro Street transmission in stock trim with 4.12 RP and ran it for two seasons. It runs very good in town and countryside driving I´m under impression it kills my 1/4 mile times a lot.

What gear ratios would you suggest for my 2276 with 86C cam, 11:1 CR , 48DRLAs, 1 3/4 CPS python. I run a full metal VW Thing on swingaxles, good rubber mounts, CSP trapese system, no problem with wheel hop whatsoever. Berg shifter, new shifter bar bushing, Dieken Copper disc and Stage 1 KEP plate. The car still weight around 2000 lbs with me.

I´m ready to run ERCOs with 215/65 m+H DOTs on the rear for the races, otherwise I´m driving on 205/65 Pirellis.

My gearing is:

4.12 RP,
1st Gear: 3,78
2nd Gear: 2,06
3rd Gear: 1,26
4th Gear: 0,89

I´m prepared to run close ratios if it still allows me to get to races at reasonable speed (no autobahns). Please design me a gerabox of your opinion.
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[jfats808]

A 1.04 4th wont be too bad to drive on the highway and still have some ratio umph. Call up Rancho and see what they say. How does your temp run atm with your current trans set up? THing going to take probably an extra fan cooler. A thing isnt exactly an aerodynamic deal also.
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2276 IDA's 86C 11-1 DD !
2017 48 Trijet DRLA's W125

[ALB]

Shorter gears are great for acceleration, but will affect highway speeds. You'll have to decide if it it's something you can live with. In my youth I at one point went to a gearbox with 4.37 r&p, 1.48 3rd and 1.12 4th gears (from a 4.125 r&p and stock gears) in my transportation. With the close ratios and shorter r&p, 3500 in 4th was about 52mph and it took forever to get places (but the car ran mid 14's at 88mph with a 1750). With the 4.125 r&p and stock gears 3500 happened at about 70mph and was probably 3/4 second slower in the 1/4 mile.
3500 x 1.04- 60mph
3500 x 1.12- 55mph
These figures all use a 24 1/2" rear tire.
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On a lifelong mission to prove (much to my wife's dismay) that Immaturity is Forever!!

[vwracerdave]

You can build a close ratio racing gearbox or a stock ratio street gearbox. Anything else will be a compromise between fast 1/4 mile ET's and happy highway driving. The only way you can have both is with a 5 speed.
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2017 Street Comp Champion - Thunder Valley Raceway Park - Noble, OK
2010 Sportsman ET Champion - Mid-America Dragway - Arkansas City, KS
1997 Sportsman ET Champion - Thunder Valley Raceway Park - Noble ,OK

[1961bluebug]

Thanks so far. I have other aircooled VWs for highway driving. So what would be your choice for real close ratio 4 speed?

Thanks,

J.
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[madmike]

Keep the 4:12 R&P and 1-2 gears and install 1:48 3rd & 1:12 4th and weld the hubs to the gears ,get a Super diff too
_________________
'Black Ice'Drag Buggy 'Turbo'
Rail Buggy 1915 turbo
76 Drag/Street bug 2180cc 'Turbo' 11:85 @113 mph"If I go any faster I'll burn up the Hamster" ,gets 28 mpg. also 10/09/22 11.90 @115 mph
"If I'm ever on Life Support,UNPLUG Me, Then Plug me back In see if that Works"

[ALB]

For a car that sees a lot of street time and only is on the track occasionally, Madmike's suggestion X2. 7000 rpm in top gear will be about 110 mph (again, assuming a 24 1/2" tire) and would be a good place to start.

For a 1/4 mile only transaxle a 3.88 ring & pinion is stronger, but for the best results custom 1st and 2nd gears will be needed as well, so it could get expensive.
_________________
On a lifelong mission to prove (much to my wife's dismay) that Immaturity is Forever!!

[ALB]

For a car that sees a lot of street time and only is on the track occasionally, Madmike's suggestion X2. 7000 rpm in top gear will be about 110 mph (again, assuming a 24 1/2" tire) and would be a good place to start.

For a 1/4 mile only transaxle a 3.88 ring & pinion is stronger, but for the best results custom 1st and 2nd gears will be needed as well, so it could get expensive.
_________________
On a lifelong mission to prove (much to my wife's dismay) that Immaturity is Forever!!

[neil68]

My 2332 cc, Web 86C, 1.75" header, IDA's, M&H 215's, etc, I first tried a Rancho 4.125 with 3.78/2.26/1.48/1.04 running low 13's in the 1/4-mile. However, it died noticeably on the 1/4-mile when shifting from 3rd to 4th.

Sold that transaxle and next I went with a 3.875 Rancho with 3.78/2.35/1.65/1.31 and all of a sudden I was down in the 12's. Of course, this limits the freeway speeds, as the rpms at 100 KM/H are getting up there
_________________
Neil.

Der Kleiner Rennwagens
68 Beetle 2332 cc, 204 WHP
12.5 seconds @ 107 mph
Dynojet Test: https://www.youtube.com/watch?v=M9B_H3eklAo

[ALB]

[Chip]

[1961bluebug]

Rviving my old thread. i modeled two graphs here:
http://www.teammfactory.com/gearcalculator.php?kmh...on+1+%26+2

First transmission is my actual transmission, second one is close ratio which I want to make out of my Pro Street. Would it work good for my application?

I´m still wondering if 1.125 or 1.21 4th would be better... I´m somehow copying neil68´s setup and want to get rid of the 3rd to 4th shift drop he mentioned above.. I also believe that my engine is similar to the engine he used...


Thanks.
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[modok]

He said he had a 1.04 fourth, and yeah that is too big a drop from the 1.48 third.

the fourth 1.48/1.125 should be perfect IMO if you don't change the mainshaft, if you space them any closer it won't feel like you even shifted


if you DO spring for a mainshaft, then maybe 3.78/2.26/1.58/1.21

[gears]

I'd advise against a swing axle super diff for street use. I've had better long term service using 15 tooth Euro side gears with dual circlips.
_________________
aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com

[neil68]

Following up on your PM.

The 4.125 with 1.21 4th is somewhat similar to my 3.875 with 1.31 4th, so great for racing...but, a bit high strung for higher speed road traffic (freeway/autobahn). I stay on roads that are 80-90 km/h only, as at 100 km/h the drivetrain is screaming a bit too much for me

The 1.12 4th might be a better choice, as others have suggested...
_________________
Neil.

Der Kleiner Rennwagens
68 Beetle 2332 cc, 204 WHP
12.5 seconds @ 107 mph
Dynojet Test: https://www.youtube.com/watch?v=M9B_H3eklAo

[AlteWagen]

[gears]

They all have oiling problems, and show excessive wear eventually. The stock diffs are wide open, and oil properly over the long haul.

Other options are LSD or TBD (although these are expensive).
_________________
aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com

[1961bluebug]

So here I am 6 years later and my car hasn´t changed yet. Ïn fact it stood in a storage for last 4 years. With early bay coming home as a 2 yr restoration project, and another 1961 bug that kept me busy.

But now I pulled the trigger and the transmission is being built. It will be Berg 5,
3.875:1 RP
3.75/2.25/1.65/1.31/0.89 gear stack.

Looking forward!
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[King_vw61]

[gears]

.
For swingaxle you'd step up to one of these:

Then again, the IRS super diffs don't suffer from the same oiling issues as the swingaxle SDs.
_________________
aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com