TheSamba.com :: View topic - Is a Rancho Pro Street transaxle good enough for 150 hp?

Tue Apr 18, 2023 9:28 am

It will be used as a daily driver. I don't intend to be too hard on it, just maybe spin the tires a couple times and call it good. I am using stock rear tires. 165/80R 15.

Tue Apr 18, 2023 9:33 am

What does Rancho say?

Tue Apr 18, 2023 10:37 am

When in doubt ......TALK TO THE GUYS THAT BUILD IT. WHY WOULD YOU ASK ANYONE ELSE.

Tue Apr 18, 2023 10:37 am

Depends if you want it to be enough or not.
You could kill it in an instant. Or with a shred of mechanical empathy it should last just fine.

Tue Apr 18, 2023 11:18 am

It isn't horsepower that breaks transaxles. It is from abuse by smoky burnouts, wheel hop, launching with slicks, aggressive tactics when stuck in snow or mud, dumping the clutch, speed shifting, too aggressive of a clutch/pressure plate, and sheer stupidity. I could put a 200 HP engine in a Bug with a stock transaxle and drive for years and never break it. I could destroy a "Pro Street" transaxle with a stock 1600 if I tried hard enough.

You need to discuss your needs and driving style with the person that will build your transaxle.

Tue Apr 18, 2023 11:51 am

It might work just fine for you if you respect it and don’t abuse it.

For myself I had one built specifically for my intended use, I didn’t buy a generic off the shelf mass produced rebuild with just a few inexpensive strength upgrades. I’m guessing they use a Super Diff and a cast aluminum aftermarket side cover along with welded 3rd and 4th gear synchros as the main upgrades.

Having the later 3.78 mainshaft is a big strength upgrade over the earlier 3.80 mainshaft as well, however if they don’t state that in their description it likely won’t have that important upgrade.

Seriously consider having your transaxle built by someone who will ask questions about your intended use and will suggest the right upgrades and what core is the best to build it off of.

The one pictured below was built to my specs, and at least half of the components used were suggested by my builder MCM Scott of Metalcraft Motorsports. If you’re not completely familiar with all the options for stock parts (many no longer available new so good used are what you get) and aftermarket parts talk to a pro who has built hundreds or thousands of them would be my suggestion.

Mine was built using a new aluminum Rhino case with 2 Dave Folts billet side covers and EMPI axles amongst other good stuff, for my upcoming 160 hp 2180 street engine build. Spend the money to do it right, buying a generic performance transaxle is something I’d never do personally.

Tue Apr 18, 2023 12:28 pm

b-man wrote: It might work just fine for you if you respect it and don’t abuse it.

For myself I had one built specifically for my intended use, I didn’t buy a generic off the shelf mass produced rebuild with just a few inexpensive strength upgrades. I’m guessing they use a Super Diff and a cast aluminum aftermarket side cover along with welded 3rd and 4th gear synchros as the main upgrades.

Having the later 3.78 mainshaft is a big strength upgrade over the earlier 3.80 mainshaft as well, however if they don’t state that in their description it likely won’t have that important upgrade.

Seriously consider having your transaxle built by someone who will ask questions about your intended use and will suggest the right upgrades and what core is the best to build it off of.

The one pictured below was built to my specs, and at least half of the components used were suggested by my builder MCM Scott of Metalcraft Motorsports. If you’re not completely familiar with all the options for stock parts (many no longer available new so good used are what you get) and aftermarket parts talk to a pro who has built hundreds or thousands of them would be my suggestion.

Mine was built using a new aluminum Rhino case with 2 Dave Folts billet side covers and EMPI axles amongst other good stuff, for my upcoming 160 hp 2180 street engine build. Spend the money to do it right, buying a generic performance transaxle is something I’d never do personally.

Don't be modest, that thing has a bunch of nice parts in it, hence the long wait time. Thanks again for the bussiness and the comradery! (spelling?)

Tue Apr 18, 2023 1:09 pm

What I am saying is that I would like reliability. Its going to be a daily after all. I just want to know what would be strong enough to take 150 hp, and just do a couple doughnuts in the yard with the kids in the back seat. Nothing too crazy.

Tue Apr 18, 2023 1:35 pm

Strong transaxles are expensive to build.

Swing axle or IRS? They’re diffent animals with the swing axle being more expensive to do right.

It’s a crapshoot if you’re not the one specifying exactly which parts you want to be new and not used when new ones are still available.

Doing donuts in the yard is abuse, you’re taking your chances just like I would be doing if I took my car to the track and ran slicks or drag radials. All it takes is for the inside wheel to come up off the ground and grab traction again to break something during donut abuse.

Call Rancho and find out exactly what you’re getting and maybe upgrade from there.

Tue Apr 18, 2023 5:32 pm

A stock Transaxle with welded sycro hubs will take 200 hp for a long time if not heavily abused in my experience.

My 67 stock Swingaxle held 150 plus hp for 3 years before the sycro hubs slipped. I had them welded and the transmission gone through to replace any worn parts and it lasted another 7 years up to 200 wheel hp before the stock spider gears let go.
I tried a Super diff but it is not for a daily driver. On long distance drives...even with oiling mods it would get hot and the axle spades would start seizing.

It now has a 10 tooth spider diff in it but is all stock except the welded sycro hubs.

I don't do burnouts but do shift quite hard.

For the price I get charged to go through a stock trans I can afford to run them a long time compared to buying a built transmission

I have a spare 68 swingaxle trans and it cost me $450.00 to have it gone through, sycro hubs welded and any wear items replaced.

Tue Apr 18, 2023 5:34 pm

Folks have said, "a stock swing axle trans can take up to 150HP". If you're nice to it!
That said, I have drag raced a stock swing axle 67 and didn't break the trans.

However a few weeks later after racing the car. I did manage to break the trans side gear, during a hard street launch. Revved up the rpm and aggressively released the clutch pedal.
Heard an awful BANG! From the rear of the car. I got lucky and managed to limp the car home.

When I drained the gear lube. I found a few chunks of side gears in the effluent.

After that I paid handsomely for a stronger trans by a local builder.
HD side gears, welded 3-4 gears, HD side plate.

^All that, was with a 158HP est. 2180.
I keep that broken tooth, as a reminder of what can happen,, when you're careless while playing with your VW.

Be careful what you do with your trans. It can cost you $$$$, to get it repaired.

Tue Apr 18, 2023 6:15 pm

The price of a "nice" trans should be at least 50% of the cost of the engine. I don't know how many times I've heard people bragging about how much money they have in an engine only to complain about the price of a gearbox.

Or they say "I want a box that will handle 150 hp, burnouts, launching the car(with effed up suspension). Then you give a price(pending parts available) and then they refere to a "named" transmission.
On top of that, they give you the most coroddid 6v pile of shit for a core,,,, because they want to keep thier core as it is still a nice trans that only jumps out of fourth and makes noise.

To the og poster, just buy a "pro this or that, freeway goodie or flier" transmission, as we all have to start somewhere

Tue Apr 18, 2023 6:16 pm

When I had my tranny rebuild I asked how much to have it insured for return shipping... I was told $6000. That was 11 years ago.

Wed Apr 19, 2023 8:26 am

b-man wrote: Strong transaxles are expensive to build.

Swing axle or IRS? They’re diffent animals with the swing axle being more expensive to do right.

It’s a crapshoot if you’re not the one specifying exactly which parts you want to be new and not used when new ones are still available.

Doing donuts in the yard is abuse, you’re taking your chances just like I would be doing if I took my car to the track and ran slicks or drag radials. All it takes is for the inside wheel to come up off the ground and grab traction again to break something during donut abuse.

Call Rancho and find out exactly what you’re getting and maybe upgrade from there.
I am going to be using a swingaxle.

Wed Apr 19, 2023 11:46 am

vw66bug wrote: b-man wrote: Strong transaxles are expensive to build.

Swing axle or IRS? They’re diffent animals with the swing axle being more expensive to do right.

It’s a crapshoot if you’re not the one specifying exactly which parts you want to be new and not used when new ones are still available.

Doing donuts in the yard is abuse, you’re taking your chances just like I would be doing if I took my car to the track and ran slicks or drag radials. All it takes is for the inside wheel to come up off the ground and grab traction again to break something during donut abuse.

Call Rancho and find out exactly what you’re getting and maybe upgrade from there.
I am going to be using a swingaxle.
And a Subaru engine I gather from your previous postings, something you need to share here so others can better evaluate your situation. A swing axle should be upgraded with all new side gears, spider gears and fulcrum plates along with Sway-A-Way or EMPI aftermarket axles, as I did for my “street racer special”.

A Subie may well be harder on the transaxle than a built VW engine putting out the same horsepower I would think because of the torque output.

The tire and wheel choice also has a big influence, lightweight wheels and narrower/smaller diameter tires help out immensely. A set of tall 31” off-road tires on 8” steel wheels are much harder on the transaxle and axles than 25.5” tall 165/80-15 street tires on lighter 5” wide Centerlines.

Reliability means don’t skimp on the transaxle. Get one built specifically for your intended use that matches your powerplant choice. Or roll the dice and hope that “pro street” transaxle will handle it.

Wed Apr 19, 2023 12:09 pm

b-man wrote: vw66bug wrote: b-man wrote: Strong transaxles are expensive to build.

Swing axle or IRS? They’re diffent animals with the swing axle being more expensive to do right.

It’s a crapshoot if you’re not the one specifying exactly which parts you want to be new and not used when new ones are still available.

Doing donuts in the yard is abuse, you’re taking your chances just like I would be doing if I took my car to the track and ran slicks or drag radials. All it takes is for the inside wheel to come up off the ground and grab traction again to break something during donut abuse.

Call Rancho and find out exactly what you’re getting and maybe upgrade from there.
I am going to be using a swingaxle.
And a Subaru engine I gather from your previous postings, something you need to share here so others can better evaluate your situation. A swing axle should be upgraded with all new side gears, spider gears and fulcrum plates along with Sway-A-Way or EMPI aftermarket axles, as I did for my “street racer special”.

A Subie may well be harder on the transaxle than a built VW engine putting out the same horsepower I would think because of the torque output.

The tire and wheel choice also has a big influence, lightweight wheels and narrower/smaller diameter tires help out immensely. A set of tall 31” off-road tires on 8” steel wheels are much harder on the transaxle and axles than 25.5” tall 165/80-15 street tires on lighter 5” wide Centerlines.

Reliability means don’t skimp on the transaxle. Get one built specifically for your intended use that matches your powerplant choice. Or roll the dice and hope that “pro street” transaxle will handle it.
I would rather not roll the dice. what transaxle would everyone here recommend for my use? 150 hp subaru swap, I would like to have a bolt in installation into a 66 beetle. stock wheels and tires.

Wed Apr 19, 2023 12:38 pm

Since you have no location posted it’s hard for anyone here to recommend someone local to you so as to avoid the cost of shipping.

I’d suggest a budget of close to double the cost of a generic “pro street transaxle, mine was north of 4k so be ready to open your wallet. Part of that additional cost is the aftermarket axles and related parts, those transaxles come without any axles.

Scott will ship whatever you want on a pallet, he’s a great builder and can recommend whatever upgrades are necessary. Probably starting with a 3.875 ring and pinion and a 3.78 mainshaft.

Choose whoever has a good reputation, I went with Scott after seeing numerous Samba members posting good experiences. His shop is a 200 mile drive one way from me, it was worth the drive just to meet the man and tour his busy shop and explain in person exactly what I wanted.

Wed Apr 19, 2023 1:06 pm

b-man wrote: Since you have no location posted it’s hard for anyone here to recommend someone local to you so as to avoid the cost of shipping.

I’d suggest a budget of close to double the cost of a generic “pro street transaxle, mine was north of 4k so be ready to open your wallet. Part of that additional cost is the aftermarket axles and related parts, those transaxles come without any axles.

Scott will ship whatever you want on a pallet, he’s a great builder and can recommend whatever upgrades are necessary. Probably starting with a 3.875 ring and pinion and a 3.78 mainshaft.

Choose whoever has a good reputation, I went with Scott after seeing numerous Samba members posting good experiences. His shop is a 200 mile drive one way from me, it was worth the drive just to meet the man and tour his busy shop and explain in person exactly what I wanted.
Canada, Alberta.

Wed Apr 19, 2023 1:56 pm

vw66bug wrote:
I would rather not roll the dice. what transaxle would everyone here recommend for my use? 150 hp subaru swap, I would like to have a bolt in installation into a 66 beetle. stock wheels and tires.

Convert to IRS. That's what we did. Otherwise, the question becomes

How many 60 year old transaxles will adequately and cost effectively handle 150hp?

Once you have an IRS setup in place you can use a much stronger Bus transaxle.

Our EJ25 is makin' around 175hp. I wonder what a 250hp WRX or a 300hp STi motor would be like?

Write a check. The Subarugears transaxle costs $8k. Their site says $4600 FOB Australia which in reality means around $8k delivered with mounts and axles. It comes in its own nifty road case.

It's a 5 speed...

Apply sweat equity. The Subarugears flippy- flop ring gear costs around $2k. I haven't checked lately. Again, the price goes up with shipping, mounts, axles and flanges.

There's a trick little part that locks out the 4WD. Or, if you can weld watch YouTube and roll your own.

Don't hack up a perfectly good '66 Bug to fit a Subaru conversion. There is a lot more room for it in a Ghia... :idea:

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Thu Apr 20, 2023 8:00 am

Dusty1 wrote:
How many 60 year old transaxles will adequately and cost effectively handle 150hp?

Once you have an IRS setup in place you can use a much stronger Bus transaxle.

Our EJ25 is makin' around 175hp. I wonder what a 250hp WRX or a 300hp STi motor would be like?

Write a check. The Subarugears transaxle costs $8k. Their site says $4600 FOB Australia which in reality means around $8k delivered with mounts and axles. It comes in its own nifty road case.

It's a 5 speed...

Apply sweat equity. The Subarugears flippy- flop ring gear costs around $2k. I haven't checked lately. Again, the price goes up with shipping, mounts, axles and flanges.

There's a trick little part that locks out the 4WD. Or, if you can weld watch YouTube and roll your own.

Don't hack up a perfectly good '66 Bug to fit a Subaru conversion. There is a lot more room for it in a Ghia... :idea:

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See that's the thing.. front end crash, rear end and side. its pretty rough. no point in keeping it original anymore. I did buy the proper repair panels and did all the repairs however. It's not original anymore lol. New dash, seats, front clip, entire side section, all of the rear sections along with all the standard rust repair. it's not even the same car anymore. I am just going for a little bit of a sleeper build. That's why I still want a swing axle. The only original looking part of the car will probably just be the exterior of the car itself, and I want a easy bolt in installation. I got the car for 100 bucks lol. dumped all my money into it, disc brakes, etc. going to be running a stock ej22, so there will not be too much hacking the car anyway. only thing left is the transaxle. I am in no rush to get things done though.