blow through turbo

[drleonvds]

hi
i'm playing with a spare 1600
built a exhaust manifold with a recon mitshubishi turbo from 2.5 diesel
put on a spare weber 38 side draft
engines runs but not very well
i'm playing around with different jets, but wonder if i should not change to a suck through
i only want a very mild setup not for racing
if i do suckthrough what carbb should/could be used
thanx
leon
strand

[jmvv]

There are pros and cons to both systems.

In a blowthrough system you have certain parts of the carb circuitry exposed to positive pressure and other parts exposed to atmospheric pressure. To get the carb to work properly the positive pressurised circuits must not interfere with the other circuits. To get this right can be a real bitch. A solution is to mount the whole carb inside a sealed presurised box (pressure from the turbo) with only the fuel line and accelerator entering the box to the carb. This will place al circuits at equal pressure and allow the carb to work. This was done by a Britsh Tuning company in the early eighties on turbo conversions of carburetted Ford V6 engines.

On a suck through system you introduce a "wet" air mixture to the turbo compressor (Fuel mixed with air) and on the long run the fuel particles leads to accelerated wear of the turbo compressor and premature failure.

For turbo applications a "dry" system with fuel injection is best. With a proper stand alone engine management system you will have the best tunabilty where it comes to fuel/ignition/engine load requirements.

Guys like 4AGEDUB really are the turbo experts.

[Edmond]

Get hold of Dave Rowley he really knows turbo setups well, he can also supply a modified weber IDF carb for blow thru turbo use.
will pm you his email address

[Tony Z]

be careful you dont kill the turbo. Petrol turbos are made to handle higher temps than diesel.
Honestly, not sure if it will make a difference.
But the turbo might be wrongly sized for the car, that might contribute to your issues

[dubster]

Can you post some pics of the setup...try get a t2.5 with 0.45 AR on the hot side....or thats what ive read...

[johanb]

hi
i'm playing with a spare 1600
built a exhaust manifold with a recon mitshubishi turbo from 2.5 diesel
put on a spare weber 38 side draft
engines runs but not very well
i'm playing around with different jets, but wonder if i should not change to a suck through
i only want a very mild setup not for racing
if i do suckthrough what carbb should/could be used
thanx
leon
strand

I like a suck thru turbo.. less hassels to set up, have discussed on this thread
http://www.aircooledvwsa.co.za/viewtopi ... =6&t=11748
and another
http://www.aircooledvwsa.co.za/viewtopi ... 3&start=15

If you running presurized carbs the best is to go for the Weber "H" carbs as they were designed for turbos. Just remember to get a very good fuel pressure regulator when going for a 'blow thru' system as petrol tend to be pushed back in the lines and make the car run lean under boost,, Obviosly with the relevant fuel pump,, Golf GTI pump work wonders.

What the turbo's are concerned, will take it to a turbo shop to have a look at as Diesel turbo's don't need as tight clearance as a Petrol turbo, that why there are more diesel turbo's cars out there than petrol (one of the reasons)

All the best with your project

Johan