70Turbobug´s 2 liter turbo

[70Turbobug]

Thanks guys!

On the TB's it looks like each throttle is independent (butterflies don't share a common shaft) My guess is it's one hell of a throttle cable splitter! Nice linear bearings on it as well.

Exactly! The 3rd pic is the junction box" where the 4 cables from the TB´s come together.The slide in the middle has ballbearings and slides on a shaft.I still need to get a CB Plate and housing.A friend of mine offered to make me housings from carbon fiber,but I´m not sure if I can get them to seal properly i.e. not be able to put much clamp pressure at the junctions.

Hi 70Turbobug and welcome.

That spec has the makings of a very quick motor.

I note you are going with a Uniball rear suspension and coilover. Why are you getting rid of the torsion bars, are you intending to race the machine?

Thanks! Occasionally I will race it. You are right about the brace.I will have one made out of steel.I had a CSP aluminum brace and I believe they are too soft.Not because it´s aluminum,but because it is cheap aluminum.The torsion bars will not be used at all and are not installed.This allows the suspension to move more freely and independantly.

You can just easily use a $200,- set of Mahle type 1 pistons, which are sort-of forged and very light weight too. They are twice as good and cost near nothing wrt this project.
and don't give me crap about the 'compression ratio' with the flat tops

Hi Wally! Well it´s hard to argue against that I guess and you are more than likely right. I had my eye on a set of Wiseco´s from JayCee advertised on VW parts unlimited for 350 Dollars.Using the stock pistons may cause a bit of misunderstanding but let me explain why I chose this way.The main enemy is temperature and rpm.A cast piston doesn´t trap the the heat as much as a forged piston.A forged piston is better for high rpm due to the denser material.I will be using piston oil squirters and will be running on E85 only and I have an efficient turbo and Intercooler.I´m optimistic that it will work out fine.Armin Klein also runs stock pistons in his 2 Liter turbos with great success on pump gas and blasting around the A1 ring at 1.8 bar all day (had a hole in his WG senseline) and the temps didn´t move away from normal values.It´s a risk I agree,but I´m not going to be revving that high eventhough the specs suggest it.

I noticed the Remmele front uniball suspension setup ... do you have a pic of that ?

Hi Sandeep! I don´t have the suspension put together yet.My Beam is getting powder coated.I will take some pics of the parts this week.

[Wally]

Originally Posted by 70Turbobug

The main enemy is temperature and rpm.A cast piston doesn´t trap the the heat as much as a forged piston..

I disagree humbly on both accounts though..
You main enemy in a turbo engine is knock. Period.
You really don't have the heads/headflow to worry about rpm.. (sorry)

The heat retention/conductivity differences of cast and forged alu is really futile in engine operation circumstances.

Knock is your enemy and you WILL encouter it sometime during tuning.
Then you have either forged ring lands or cast ring lands...
Thats my main point

[evilC]

Originally Posted by 70Turbobug

Thanks guys!
...................
Thanks! Occasionally I will race it. You are right about the brace.I will have one made out of steel.I had a CSP aluminum brace and I believe they are too soft.Not because it´s aluminum,but because it is cheap aluminum.The torsion bars will not be used at all and are not installed.This allows the suspension to move more freely and independantly.


...............

I don't agree about the suspension moving more freely. The only advantage to using the uniball set up is the adjustability for a race set up where various springs can be substituted. The torsion bars do allow the loads to be rgidly and efficiently transferred into the heart of the chassis whereas the Cup brace, although fully triangulated, still allows some flex. If this is primarily a road car then the torsion bar set up supplemented with helper springs on coil overs will give you the adjustability you need for the occasional foray onto the track. With this system the light weight alloy cup brace will be more than sufficient to control any residual loads and stiffen the frame horns.

Porsche ran their '70s 934s and 935s with uniball/coilovers not because the torsion bars were deficient but because it saved weight and it gave them a greater selection of spring rates. Neither of those reasons would apply to your bug.

Clive

[Humble]

Sounds like you'll have a hell of a motor when it comes together got any plans for the poor 091?

On the piston issue it doesn't make sense cost wise to use a cast piston. Even if you have already built the motor and gone through break in I would still strip it and get forged pistons. Those cheap cast pistons will cost you a fortune when they go, not if, when. It could be just a ring land (new piston and barrel maybe some head work), or maybe the piston crown goes (time for a new head, rod, maybe crank, cam, lifters, possible fire damage). The point is $200 now could save you thousands down the road.

I would also stay away from the wiesco pistons for a turbo motor. Even though they are forged the upper ring land is very thin and doesn't hold up the detonation under boost.