NG horsepower upgrades

[Alan Pritchard]

Thanks Jorgen, so perhaps my work may be a bit trickier than anticipated..
my cam will be my 272, I will not be using equal length headers, and as for
cr of 12:1, sounds a bit high for my liking for reliability, what is
everyones opinion on a sensible cr? I do plan on keeping the intake temp as
low as possible by isolating the 2 manifolds with a suitable coating, and a
heat shield. Cold air will be routed in (from somewhere :S).
Anyway, on holiday from today, so hopefully by the time im back on list ill
have a box full of bits to examine ;)

Best Regards,
Alan Pritchard

Network Administrator
Mechanical Design Engineer
Seaeye Marine Ltd.
+44 (0)1329 289000

 -----Original Message-----
From: 	Jörgen Karlsson [mailto:jorgen.m.karlsson at home.se] 
Sent:	26 August 2004 19:06
To:	quattro at audifans.com
Subject:	SV: NG horsepower upgrades


> Now ditch cis, the figures I have heard of for removing the airflow
> restriction are reputed to be between 15-20......
> So ditching cis, going efi and programmable ignition...... according to
> others, should unleash 27-37 hp..... these seem incredibly high
> figures, but
> this is working on ideas I have  heard....add that to a
> conservative 160 hp
> for a ng with raised cr, lumpy cam, p+p and bv head, good downpipe and
> exhaust system.

I have used EFI on an otherwise stock I5, don't know the engine code but the
engine was an european 130hp solid lifter engine (2144cc). I didn't optimize
the ignition and only spend a few minutes mapping the fuel but the
difference compared to CIS was huge. The logs indicated that the little
80Q -83 did the 0-60mph sprint faster then a stock 200TQ. I would not be
surprised if it had 140hp on the crank.

To get anywhere near 200hp most stock parts has to be replaced with custom
items. That incudes a custom intake and I5 header.

I have done a few simulations and it seem hard to reach 200hp without
sacrificing drivability or emission compliance. A _good_ port job, 40/35
valves, 276deg cam with 12.7mm lift, 12:1CR, thermally isolated intake with
10" primaries, 3" TB, 30-38" tuned 5-1 headers and a free flowing 2.5"
exhaust should put you at over 190hp with good vaccum and a stock like low
rpm range.

But with all that money in the engine it would feel strange not to go with a
295 - 308 deg cam instead. My simulations indicate that it really unleach
the power on a free flowing head. 210-225hp with these cams also match what
I have seen here on well built 2v engines.

Note that the _good_ port job is the equalizer, the differencies between
good and bad heads tend to disappear when a real wizard gets his hands on
them. The ports have a bit thin walls on the 10v heads though, some welding
may be required to build an optimal port.

Jörgen


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