Re: My thoughts on 1.8T motors

["Chris DeLong" <green536@hotmail.com>]

<x-flowed>Thats some very good input Mike. Thanks!!


>From: Mike Smith <Mike.s@ise.co.uk>
>To: scirocco-l@scirocco.org
>Subject: My thoughts on 1.8T motors
>Date: Mon, 25 Oct 1999 11:08:24 +0100
>
>Hi All,
>
>My thoughts on the 1.8 20V (and 1.8T):
>
>The engines in the A3 / Golf / TT are mechanically identical. The Golf / A3
>have some slight
>differences in the layout of the inlet manifold on the non-T version.
>The Audi TT 'T' engine is slightly more powerful then the A3 / Golf 'T'
>through tweaks to the
>management / turbo / cams, and also has variable valve timing as per the
>non-T. The A3 / Golf
>'T' engine does not have variable valve timing, but almost all the late
>non-T engines do.
>
>There are two versions of this engine though:
>
>The version fitted to the A3 / Golf is a completely new block, which has an
>integral water pump.
>The exterior of the engine is very different to the Scirocco style lump
>which we are so familiar with.
>There are BIG problems with fitting the A3 lump into the Scirocco because
>the engine mount
>is **totally** different on the new block. You need to do some major cut 
>and
>paste on the chassis
>leg to get it to fit.
>(note - the very early engines are not like this, but anything you could 
>buy
>from the factory would
>be. See below)
>
>The 20V engine in the A4 / Passat is almost exactly the same block as the
>Scirocco, and will fit
>straight in. It has the same cylinder head as the A3 one, but the only
>problem then is the exhaust
>manifold and turbo location, which is obviously completely wrong, being
>arranged longitudinally.
>The very first A3/Golf engines used this block, but they changed it for the
>new one after a short while.
>
>The ideal solution is the A4 engine, with the A3 exhaust manifold and 
>turbo.
>This would be almost bolt-in.
>The cylinder heads are the same between the two blocks, btw.
>
>As far as throttle control, etc, these engines are cable throttle, but they
>have a very sophisticated
>'closed-loop' idle control which has a servomotor on the throttle body 
>which
>can move the throttle
>plate to control the idle. The engine management is extremely advanced as
>well. Consider this:
>Digifant II management for the 8V 1.8 Golf II engine uses about 16K of
>memory for its 'map'.
>The G60 Digifant (Corrado) uses 256k. The Motronic used on the 20V engines
>(T & non-T) uses
>2MB!!! This has control maps for virtually every aspect of the engine,
>including the obvious ignition
>timing, sequential injection (on some versions), turbo boost control,
>variable valve timing, idle-servo, etc.
>
>Both versions of the engine are highly restricted in standard trim. The
>turbo engine is trying to
>breathe through a manifold outlet of about 1 inch diameter! It also has
>softer cams than the non-t,
>and a restrictive inlet manifold design. It doesn't have the variable valve
>timing that the non-T has,
>and the management is programmed to produce exactly 150bhp and no more. All
>the tuning of this
>engine that I have seen in Europe consisted of fitting a proper turbo, and
>reprogramming the ecu. That
>will net you at least 280bhp, without even taking the cylinger head cover
>off!
>The non-T 20V engine will easily make 160-170bhp with decent inlet and
>exhaust design.
>
>Mike Truluck of Jabbasport (mkI Scirocco G60 20V 4wd) has used an A4 turbo
>engine, a highly
>modified G60 supercharger, G60 management, and variable valve control from 
>a
>non-T. Other than
>ceramic coating the pistons, this engine has no internal modifications, and
>makes about 350bhp!!!
>(that said, I don't think even the original designer would now recognise it
>from the outside!)
>
>Sorry for the long post, but I have researched this quite a lot by virtue 
>of
>having just fitted an A4 20V
>engine to my Polo (without the turbo - I'll be using a Rotrex supercharger
>when funds allow)
>
>BTW, all this applies to European engines - whether the US versions are
>substantially different
>remains to be seen...
>
>Cheers!
>
>	Mike
>
>--
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>


Chris DeLong
ICQ#45030867
'80 16V Rag
'65 Bus (ugly, but good for campin' W/toaster oven)
'82 GLI
'80 'Vert
'61 17 Window
'78 Scirocco


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