R32 Turbo Onto 1600cc Vw Motor

[lows_13]

My friends wants to turbocharge his 1600cc VW engine.

I want to use a R32 standard turbo as i can use my old dump pipe, etc, etc.

The tricky part of the conversion is, the carby needs to be located prior to inlet of turbo.

As it needs to be a suck through system. So the Dynamic seal inside the R32 turbo would need

to be changed to a Carbon seal so that fuel can pass through the turbo.

What would happen if a ran a setup with a pod on the inlet and a SU carby prior to inlet manifold,

will this work so that i can leave the turbo seal alone?

Someone has said that the increase of pressure may cause the SU to run incorrectly....

Edited March 29, 2007 by lows_13

[discopotato03]

Carburetted turbo setups are not nice but anyhow .

You mentioned a "Blow Through" system which means the turbocharger literally blowing air through the carburettor and into the engine .

When the carburettor is on the atmosphere side of the turbocharger (upstream) is is said to be suckthrough . Actually the term is nonsensical because the turbo can't "suck" , it can create a depression or area of lower pressure before the carburettor and then its up to the atmosphere to "push" the air through .

Both systems are poor because .

1) Blow through : The whole carburettor/s need to be enclosed in a box so that positive pressure doesn't blow air out of every orifice the carby has ie throttle plate shaft/s . You have to pressurise the float bowl/s otherwise positive pressure blows fuel out the jets rather than the air stream drawing fuel in through the venturis . According to David Visard you need to put rings inside the throats of an open choke carburettor in an attempt to make it boost sensative . Different situation with constant depression carbs like SU's or CD Strombergs .

Provided you get on top of all these issues its usually the better method . You don't have to bother with a carbon or dynamic (mechanical face seal) doing it this way provided the air filter has no noticable pressure drop .

2)"Suck Through" : This really is a crude read shitty system . The carburettor is upstream of the turbo so from its point of view it just has what it thinks is a larger engine drawing on it . It all gets bad because the throttle mechanism is upstream of the compressor housing so this see's lower than atmospheric pressure , lower pressure than is inside the turbos bearing housing so it tends to draw its lube oil out through the compressor end seal - if its a labirinth or piston ring type seal . Horror no 2 is that all of the engines air and fuel goes through the compressors housing and into the inlet manifold . Its all full of fuel vapor (wet systemn) so when you close the throttle its impossible to stop the engine running filthy rich on the over run . No3 , you have to then feed lots of fuel back in when you open the throttle in an attemp to get around the lean or flat spot . Very poor mixture control is the result . Single carb inlet manifolds are usually very crude and even then stupid things like overly rich mixtures are needed to cater for the worst fed cylinder . 4 Shoud the engine spit back or backfire there's lots of fuel and air in the inlet system and you can guess the result .

Really either system is only good for mild performance increases and don't get anywhere near the result of blow through multipoint EFI . You would have to rate very crudly made inlet manifolds with the cheapest nastiest EFI system available as lightyears ahead of carburetted turbocharger systems . The fact that the conversion is going on an NA engine is a worry because they are very easily damaged in a boosted environment .

My advise is don't do it , it will not be cheap/easy/effective so IMO not worth the effort .

Your call .

[paulr33]

carby & turbo = forget it

[lows_13]

What would be the best carby to use for a 'Blow through' system?

Stromberg?...

[paulr33]

do not run an intercooler whatever you do

[lows_13]

I didn't plan to.

Would it cause problems though if i did?

[paulr33]

it will explode

[lows_13]

I assume you are talking about a Suck through system?

In theory a Blow through system should work with a intercooler?

[paulr33]

do not use an intercooler on a carby

period. regardless of setup.

its a bomb. it will explode

[lows_13]

Ok, duley noted

[understated]

If you are ingenious and cluey enough to put a turbo on a v-dub engine, then u are ingenious and cluey enough to build an efi system for it. It will be more reliable, smoother and easier to tune and less likely to be a grenade waiting to explode. Upon my internet browsing I stumbled across www.megasquirt.info which is about a DIY efi project which seems cheap enough to set up if you're that way inclined. My last car before my r33 gtst was a 63 bug, and even with a stock engine it had pinging problems. So I suspect something would have to be done about the compression ratio.

[lows_13]

Installing EFI is a option we have considered, we've yet to work out a rough cost though.

I'd imagine it would be at least $1000 +

I plan on making the turbo setup and running it, if the compression needs to be lowered

we have another motor we can re-build with lower compression