[s-cars] RS2 Conversion and Taboo Question...

[S4audinut at aol.com]

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In a message dated 07/30/2002 9:29:00 PM Eastern Daylight Time,
t44tq at mindspring.com writes:


> If you put a larger turbo on your car, it will spool slower- if
> you want low end and high end increases, that won't happen unless
> you increase displacement.
>
> Taka
>
>

Taka,
In theory and talking about fully maximized setups I agree. I think that it
will be surprising to see how much a well balanced engine and a good (better
than rs2) exhaust manifold will do to speed spoolup. My current setup is fine
to drive around town with a lot of power above 3200 and this is due to the
upgrading of components. Anyone thinking of grtting much bigger than the rs2
turbo should look at going thru the engine and strengthening and freshening
top to bottom. I dont advise anyone to put bigger than a rs2 turbo by more
than 10%, unless you go all the way.  I think anyone who is honest will say
that getting one of these to run well above the 340 hp level is hard. Going
above that will take a lot more work and some custom pieces. So yeah, if you
dont do it right you suffer big time by having a big turbo without the energy
to drive it. You can however minimize the boost threshold by building the
engine for 'super duty' and getting air in and out of the engine ( the bigger
SQ maf and the bigger and more eff. sq ex.mani.) . While the rs2 exh mani.
was an improvement over stock I saw  much better % of perf. increase after SQ
exh. I beleive that this is because the exhaust pulses have been ' tuned ' to
spin the turbo more effeciently. The equi-tube headers on some cars currently
being finished take this to the limit but are much harder to maintain vs. the
cast SQ and slip joint custom pieces. You can get extreme acceleration about
400rpm higer than where the rs2 comes on but having had both setups I feel
the maximized setup with much bigger turbo has no down sides, with the
notable exception of the large leak in cash flow.
SSSSSO yeah unless you go all the way, you dont need a t54 turbo, let alone
the 57/60 or like Tommys friend the T66, and it will hurt your overall perf.,
but the pull for a second is Good. The increase of displacement to the point
where it requires a diesel block has to be done right, but will (always has)
give significant increases in low end torque which will increase low end
accaeleration/exhaust gas energy and put the turbo to work sooner. The jury
is out about what this will do at top end (6500+) without significant
lightening and knifedge of the counterweights on the diesel crank. This costs
even more money which in my opinion should only be done if everything else is
maximized.  Some rally guys use this setup and is is supposed to be great to
6000rpm.
Rod