turbo modification (alan pritchard)

[Julian Stafford]

>Message: 4
>From: "alan pritchard" <alanthecelt at alanthecelt.screaming.net>
>To: <quattro at audifans.com>, "Adam Queripel" <adam at queripel.demon.co.uk>
>Subject: turbo modification
>Date: Sat, 27 Oct 2001 18:11:08 +0100

>I found a turbo in the scrapyard today, seems in good condition,  it has =
>an integral wastegate and it is a garret.  it came off of a mg metro =
>turbo (1275cc)  so im hoping it will be the basis for my lightly blown =
>coupe gt(t).
>
>I have a few questions though, obviously this turbo assembly is designed =
>to produce approx 5-7 psi at peak revs ,  i guess 4500 ish from a 1275 =
>cc engine.  Obviously this turbo will spin up quicker as my engine is =
>2144cc, and the wastgate will also open earlier, so what effect will =
>running the turbo with the wastegate open from lower revs have?  will it =
>be possible to run the turbo too fast and cause damage?  also the cfm =
>for the turbo will be much lower than an equivalent factory fitted =
>turbo, therefore i will have lower boost, but will this cause the engine =
>to suffocate???
>hopefully with this amount of low boost i will not require an =
>intercooler, but will have to stop the airbox from inflating/ leaking, =
>fabricate a manifold and downpipe adaptor, also do something with the =
>pipe that goes from the manifold to the metering head,  but will my =
>current fuel regulator compensate for positive manifold pressure (ke =
>engine , k jet) or would i be best to make a pcb to drive the 6th =
>injector?
>whats everyones opinion on not doing it the audi way?

The turbine and compressor housing and wheel sizes will be totally
inappropriate for the application. Think what the MG turbo engine made, less
than 100BHP, that turbo of yours is likely to restrict the output of the CGT
rather than boost it!

Consider also the massive work required, you would be much better of buying
an old 200 turbo and swapping the entire engine/fuel/turbo assy, 170 BHP
standard without I/C.

Regards Julian Stafford