Re: How to Keep the Tourque Low in the Power Band

["Randy B" <sirocco@telocity.com>]

Tosha wrote:
> > I am planing on building up an Audi 2.0 bubble block (w/ 84 GTI head)
> > this summer and adding it to my Mk1 Scirocco.  [Finally]

Scott wrote:
> There's plenty of torque with this package.

I agree, you will get pretty good torque from the 8V, my 1.9 isn't a monster
but she does have a lot of torque.
Q. Can you actually mount the JH solid lifter head to the 2.0 motor without
modification?

> > I wanted to avoid pushing the power band up into the stratosphere
> > because, well, I like low end torque more than screaming revs.
>
> -smart! Horsepower gets the mack daddy points with the chicks. Torque wins
> on the street.
>
> > Larger exhaust (w/ lower back pressure), porting and polishing the head
> > and intake, all these seem to have trade offs I could live without.
>
> You'll be fine with a 2.0" Techtonics exhaust. A *properly* ported head
with
> stock-sized valves will certainly boost your grunt as well as high-rpm
> power. IIRC, you can also install valves from a crossflow head and make
some
> minor gains. The stem diameter is a mm or two slimmer or something.
However,
> some machine work might be needed -making it a low gain/dollar
modification.
> I forget the exact details.

When I had the JH head worked on for the tt1.9, I had a race shop "pocket
port" the head and shorten the valve guides.
I have no complaints :) She will pull hard as low as 3200rmp and still pull
up to 7K (actuall put the tach into the gas gauge once in 3rd @ 7150) 8^]
Because of the shortened valve guides I was told the head would only last
about 60K before needing new guides.
This seems like it might be a good time to replace the valves.
Where can I find more info on the slimmer cross flow valves, are they the
same dia. as the ones in the big valve JH head.
I am also considering running a smaller exhaust system (1 7/8) because I now
have too little backpressure for the 1.9. (Bellvue MS tri-Y header, no cat,
Autotech 2" exhaust, and a free flow muffler)
Do you think a slightly smaller exhaust would be an advantage for torque. (I
really don't drive much above 6500, at least not daily)

> > So, rather than making a sewing machine out of my tractor, how can I
> > keep it low but still flow?
>
> early 4/2 iron manifold
> Techtonics 2/1 downpipe (long non-cat version for most torque)
> 2.0" Techtonics exhaust (there is nothing better than TT)
> knock sensor ignition (running Audi/1986 GTI map)
> full-throttle fuel enrichment circuit (from Rabbit GTI, etc.)
> G-grind camshaft
> Audi/A2/etc. throttle body on ported intake manifold plenum
> ported intake manifold runners
> 4.25 ring & pinion!!!!*

What about a lightened flywheel?
An adjustable cam sprocket is also invaluable. I had to play with mine for
awhile before landing on 2 deg adv. She now makes power where "I" want it.
Knock sensor ignition? Is this really needed? Would the CR be the same as
stock (the 2.0) if you run the JH head?
Could a thicker head gasket be used to lower it?
Seems 10:1 would be fine with 92oct gasoline if you are running an oil
cooler.
I am running 9.7:1 with 15 initial/32 final (<IIRC) with an oil cooler and
have only had predetonation with 87oct at WOT in 5th.
I do plan on installing the full-throttle fuel enrichment (had it on my old
Cosmos-JH and there was a noticeable difference)
Porting the intake plenum and runners? Why not use a VW Fox plenum?
I actually had to have the intake runners on the head enlarged to match port
the Plenum/head.
The VW Fox manifold already has a larger plenum, larger dia runners and
longer runners than the Rabbit/Scirocco setup.
The Audi 5K TB is a direct bolt on to this plenum.
I totally agree on the G-grind although I have been thinking about
experimenting with other cams for my motor.
If you could get enough torque out of the motor wouldn't the FF be the ideal
transmission?
With about 20 more hp I think it would be perfect with my 1.9.
If I can't find those extra ponies I will eventually have to find a new
gearbox :(

> *do this and you'll be able to run a ferocious cam and still lay stripes
> down the block

he he, now there is an expensive proposition, :^)

Sorry to jump in on this one, but I have been thinking about this stuff for
awile now.
Other combo's I have been thinking about:
Turbocharging the tt motor (Randy at tt sternly steered me away from this),
Installing the 1.8L G-60 motor (Cost prohibitive and too much down time),
Pulling the tt motor in favor of a CIS-Lambda controlled, solid lifter,
stroked (95.5 X 83) 2.1L 8V.
(see no reason not to do this except for loosing the uniqueness of having a
Techtonics built motor)
Find ways to get more power from the 1.9L without losing it's driveability
or ability to be smogged.
(What I have finially decided to pursue)
Thanks,

Randy
81 Scirocco S (X2) - "The Twins"





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