hey guys, was wondering what sort of drivetrain would be reccomended to handle about 300rwhp rotary (thats my ultimate goal). i know i could just get a transmission in the short term that can handle the standard 200 or whatever it would make with a microtech and higher boost.

but it is too easy to get carried away with rotors.

so suggestions would be GREATLY appreciated. as now that i have a job i have to start making decisions and aiming for something.

Anthony

Lenco airshift 4speed and a Mark Williams 9inch rear end.

71, this is a street car right? You're not made of money either, right? Coz a 300rwHP rotor won't last very long under a young man's right foot.

No only that, but you'd need a very extensive custom chassis to deal with that sort of power in a beetle. Might be time to to do a rethink. 200rwHP will make it dangerously fast, that right, with an emphasis on dangerous. Talk to any onf the guys racing proper VW drag cars on the forum and they'll tell you.

Now, u2u Quickcamper and ask him how much power his old 13Bt produced and what held it in the bus. Then speak to the local VW guy you'll be dealing with and find out how you're gonna stop the car literally ripping itself in two.

A stock series5 13bt with an aftermarket ECU, exhaust and 12psi of boost will put out around 200hp at the rear wheels.
This is enough to rip the teeth clean off first and second gears just accelerating when the turbo hits full boost.

I think traction is the enemy with this engine mounted in the rear end of a beetle.

A 200hp rotary + extra rear wheel weight + big rubber + heavy clutch = massive load on the gearbox.

Ive had stock kombi boxes last as little as one week on the street in my car with this setup.

Build a decent gearbox. Theres nothing worse than having to hold back worried that somethings going to break.

hi mate i don't care how young you are and sometimes it's good to dream, you will find the same thing said to you all the time. the weakest link in the drive train is the transaxle. sort this out and all is fine. for example my transaxle is worth 4000/5000 thousand way more than my bus is worth.as for the motor being a 13bt they are fine they rev hard and go great yes you will need deep pockets but thats the sacrifice you make, quickcamper sold his 405 rwhp 13bt for about $4500 which i believe is a dam good price for a high hp well sorted motor. as for body mods you should be looking at a drag car. at the syd dyno day wayne penrose in his purpose built strip monster pulled 270 rwhp. so good luck and happy planing.
if you want a chassis that will handle it go for a kombi they look way cooler then bug anyway ha ha ha ha
cheers
wacked1


[Edited on 16/3/2005 by wacked1]

haha not a fan of the kombi. the aerodynamis are somewhat similar to a brick

300rwhp isnt too hard to pull from a 13bt rotor.

i am wondering about suggestions for drivetrain. eg which box to use, axles .etc


remember that rotors arent the torqueist of motors. and only actually rev to 7k

Anthony

What do you mean by this Anthony:

"and only actually rev to 7k"

I used to rally an RX3 with a 13b in it (long before I'd ever heard of a turbo Rx) and that used to rev WAY over 7k.
12 to 13k if my memory is not too faded!

yeah the atmo rotarys can rev to 12-13k. but the redline on a 13bt is actually 7k. and i dont plan on bridgeport or anything so it wont rev any higher.

Anthony

How are you going to get the big power...just boost it up? Not sure about rotors...Apart from the various ports, seals and exhaust and obviously engine management....what else do they do?

Get a rancho from the states....they are pretty good, not so exoensive and you will read about them taking 500hp out of 2.8 litre turbo charged sand rails. You know they have special raised points on their rims , because they spin them inside the tyres....

Is it just going to be a drag car???? If just a street beast then it doesnt have to be as full on...unless you are prone to hard starts everytime you get in it.

Matt

street beast is what it will be.

i plan on having a 13bt with an extend port, get the motor dowelled. highflow turbo (maybe bigger). microtech. more boost.

should make close to 300 atw.

u sure a rancho can handle 300 atw?

which rancho box are you referring to?

and what do you mean hard to start and doesnt have to be as full on?

Anthony

Same problem here, don't know which gear box to put on my 280hp suby engine. I called Rancho performance about it and the person at the shop said the rancho pro street/drag couldn't handle that power. He said something about I needed an an automatic gear box from rancho but I don't have any more info on that.

I have a set of steel brace plates that hold the gearbox together for drag racing, they dont do me much good as they sit in a box cos I'm too lazy to actually fit them.
You may already be aware that Herbie Has a Rotary in him, and will be getting the bridge turbo treatment when money permits,

I find I have more trouble with axel tram than anything, he needs some sort of Brace to the body to limit the twist on the frame horns.

I'm more worried about making him stop before I make him any faster.
I used to run Water/alcohol injection on my Turbo rx2 coupe,
What a blast, nothing could ever catch it, it would hit 22 psi and just fry tyres, I used to race motor bikes as they were the only good match.

Porsche G50 box or the 915 box with a Modena Engineering disc diff with 2 ramps he makes diff centres for all types cars and motor sport and supplys them world wide and he is located in Melbourne ph 0397824420 I,m looking at using his diff, they also make torque biassing diffs and willing to talk to you as well.

yeah i'm running a 5L with 915

Not Hard to start....Hard starts, just a term for holding, say 5000 rpm and dumping the clutch.

Jak, Paul, myself and I believe Humpty's brothers wrx powered notch all have late model single side plate box's with some form of upgraded diff. It took ages for Humpty's brothers box to go, and the type 3 is heavy.

Get an L bug box with a superdiff, get your brakes and suspension done.....then if you end up braking it...get something else..if you dont brake it then .:thumb

Choppa's notch had all Albins gears in it too - it was a 'built' SSP box.

This is a very interesting discussion, as to what is 'capable' it all depends on how you drive it and what clutch you put in it. Its shock loading that destroys gearboxes if I'm not mistaken, so if you were to stick with a more conventional friction material, and just upgrade the clamping force you will have a clutch that 'takes up' slightly slower than the on/off nature of brass puck and the like. The slower the take up (we are talking factions of a second), the less shock load transmitted to the box.

The less load, the lower the bearing force between the gear teeth meshing faces, which means lower pitting stress and lower bending stress on the actual tooth itself. Lower stress = longer life.

I'd imagine that a good clean tranny oil would make a difference too.

Reuben (VWRX) has a G50 in his, and I believe (dont take it as gospel) that his EJ20 is about 350 at the flywheel. Mind you, a G50 box is about $6000, + alot of heartache to fit (think full custom cradle, cutting about six inches out of the torsion bars, coil over conversion and custom shift linkage).

I agree 100% with Boof. Get a rebuilt single side plate IRS box. Replace all the bearings, ensure the synchros are good (replace if required). Consider getting 1st and 2nd welded. Install a super diff (4 spider gear conversion and heavier diff carrier), and consider a strengthened side plate. Spend some dollars on a modified pressure plate, to increase the clamping force, but use a conventional type (Wes can give some good advice here) friction / clutch plate.

Drive the above gearbox sensibly and it should last you a lifetime. Drive it spiritedly and it should still last quite a while. Try and destroy it and I am sure you will succeed.

I have personally been in a bug that produced around 270 rwhp (Keith Hauslers HALTEC TO4'ed) some years back and from memory that car ran SSP box built by Shimo I believe....Now this car hooked along nicely (12second ET's I think!), made very good streetable power and managed to ripe the car to shreads...Keith wasn't exactly gentle with the car, but he wasn't totally nuts either!
My brothers Notch is way more driveable at a fraction of the cost and it took 5 years to kill the last TRANSFORM transaxle. I think the clutch Mark was using was BERG disc and KEP 2100lbs PP. A little heavy on the left foot in traffic, but continues to do the job 7 years on. Crap tyres help...No traction mean longer transaxle life!!! :duh
Just remember to dial out any axle tramp. Personally 300rwhp is nuts and IMHO, unuseable on the street, but at the track, things could be different. I like my cars to be driveable, but maybe I'm just getting old!!

this would be a street/strip/track day car.

would not be a daily driver, just a weekend car with occasional weekday drives.

but would also like to be able to drag it a few times and take it to track days when they are on.

some hard launches would be used. but not everywhere i go.

i thought about the porsche g50 option but like someone said. its a shitload of work and money.

this might help somewhat.

Anthony

would this power - weight be legal in a bug in Perth? i know in parts of Aus it is illegal/very difficult to register a powerful subi-bug, so should make sure it will be possible to pass reg first. as far as gearbox goes, maybe talk to the boys at RC Speedsters. they are building replica speedsters with scoobi engines and are sopposedly using a VW 4spd tranny, cars are meant to be up to full current RTA requirements, so might eb interesting to see how they build their boxes.

Right on Kojak, U hairy little man.

Anthony. My notch is similar ideas tho less power and an absolute daily drive.
I now run full synthetic oil in the box and run a KEP 2300 PP. Stage three I think they call it. The disc is an old Berg street strip, which doesnt seem to have worn in 7 years.
An important point to remember when doing a drag start is to preload the tranny.That is to roll up to the line with the handbrake slightly on and hold it there till the last yellow.
This will remove all the tolerance/backlash out of the trans and help your box . Anouther prob is axle tramp. All comes from soft springplate bushes , soft engine and gearbox mounts and chassis flex and crap tyres , like I run. I think the weight of your wheel and tyre combo and shocks and torsion bars will also affect axle tramp. Thats possibly one reason why the North Americans use light skinny wheels and tyres.Better "roll out" they say.

Transform said to me recently that to handle big power, they would recomend a Mendolia box. These are super tough im told and a virtual bolt in .So I hear. Sometimes you will see an add for this box in Hot Vw's magazine. Prices start at about 2.5 k USD.

My main concern over the years is that I just cant stop this car. So I am mostly very carefull where I use its full potential.

Its all good fun. Good luck with this project, you wont regret doing it.

Choppa

thanks mate.

good to hear from someone else in perth taht has done a conversion.

by time 13b goes in i would have alrady done brakes, suspension, transmission. motor would be the last thing to go in.

mendiola box = BIG dollars. 2.5k? where u see that i looked on the site and they were like 6k U.S

by axle tramp do u mean wheel hop? :s

im not very familiar with the term axle tramp.

Anthony

axle tramp = wheel hop. Same thing.

Anthony,

What is the figure that automatically jumps into your head when you are doing the costings for the car. We have a rough idea of allocated funds to each section..what is yours for the box.......

This will be the deciding factor...So your post would have read..What is the best box for about $2000(example ) for my 13b turbo..which will be used for occasional drags, track events...but mostly street smashing.

Your choices and advice will then be specific to your budget...
Do not forget CV's and drive shafts.......Although I think Steve Carter recently said he would rather shatter a CV and replace it on the spot, than transfer the breakage some where harded to fix(more$$$$), like inside the box.

Matt

yeah thats why i just said drivetrain. i meant wat axles, cv's .etc to use.

and as for box. i am not sure of budget for box.

but i will spend wat it takes , maybe not first off but i will eventually spend wat it takes

Anthony

So,

At first go with the SSP box with albins and a superdiff. It has been tried on cars before and done well for the money..then from there you will have a base from which you may or may not need to progress from. Takes a while working out clutch, box etc...luckily its easy to pull motors and boxes out. Mine had been in and out 3 times in the first month...Good luck...

Matt

yeah. im thinking of having a removable rear apron for ease of pulling motor. cos i figure with a conversion it will need to be done alot at the start until everything is worked out.

so...a fresh ssp with albins and superdiff. all albins gears or just 1st, 2nd?

Anthony

has anyone got a full cost on rebuilding s/s/p box with albin gears 1st,2nd&3rd, super diff ,heavy duty sidecover andfull rebuild plus none welded stubs if changing cv,s .

Depends how much you get charged for the build..I paid $150 for the box, $450 for the diff, cant remember what the gears were..I think $450 for the set????..figured it would be about $1500-$2000. Anyone.....???

The removable rear apron is the best thing you can do...I pulled my engine by myself with removing everything but the wiring(wasnt in) at 1am in 25 mins..pulled it out on the jack, and then fitted the next morning alone as well....would have been alot harder with the panel in place.

Matt

$500 for a set of Albins gears is pretty good - if I ever need to rebuild my box thats what will go back in there. Currently all it has is a superdiff and a few new bearings.

Anthony.

Gearboxes! Ask 10 people.......

In my opinion you should get your box built by someone who knows.
And who has access to parts.
Thats why I would recomend that you talk to a proper VW Trans crowd.
I dont know any here in Oz.
Thats why I call California.
The price for the Mendiola was from Transform in Long Beach.
I would call them or Rancho or someone similar.
Get them to advise you on what you need.
These guy's know what they are doin.

If you do want to go to a non standard 1st and 2nd gear sets , then your gonna need an aftermarket mainshaft like FTC's cos from my memory 1 and 2 are machined on the mainshaft. I run HD superbeetle mainshaft, which is strong but not unbreakable.I now run a 3.88 R&P but I was running a 4.12. The 412 is good and ive heard that Muffler Mike ran one in his big power bracket racer for years without it failing.
Definately weld 3 and 4 syncro's and get 181 output flanges.
So you can run Bus Cv's. You can buy T1 stb axles with T2 flanges welded from the US or get them made local. I think Troy down at VW Repairs has em on his buggy. Mine are from Transform.
I run a regular trans case with aftermarket heavy cover on the left side , cos this is where the load is. SSP boxes are not really needed for their case. Just the mainshaft and diff if you like the 3.88. and strong 4th I think.
Get a good super diff and..and...and.

Thats enough me gassin

Choppa