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Eric,
We understand your concern with low end torque production and respect your views!
Our only point is that a majority of our LH street customers are in hopes of creating maximum engine horsepower within the rpm range of the LH system (6200 engine rpm). This is accomplished by targeting upgrades for optimal use/provision at the maximum allowable engine rpm/6200 and will include camshafts, a properly formatted/updated 2.0 liter cylinder head/intake manifold, turbocharger, etc. If torque is a concern with the end user, we can typically reduce compression ratio, cam profile, or turbocharging boost pressures.
At the point of maximizing engine horsepower through the above listed modifications, employment of a 2.1 liter cylinder head and intake manifold would only reduce overall bhp/torque at 3,4,5, and 6K engine rpm. Because of the dramatic drop in induction velocity, we would also see a narrowing of the useable hp/torque band by nearly 750 rpm.
The EV-1 was a SAAB prototype that we have had direct experience with. Our initial street cylinder heads from the late 80s were even following the design of the EV-1 port and plenum design...a design which made use of a properly updated 2.0 liter cylinder head and intake manifold. Most of SAABs most progressive designs employed cylinder head intake port sizing only 7% larger than OEM production whereas the 2.1 liter port sizing is nearly twice this at . Port restrictions are eliminated/reduced but the overall size is kept realistic for engine rpm and specifics. This can allow for an up to 30% increase of volumetric improvement while fully retaining port velocities. Even SAAB understood the importance of induction port velocities and the effects on overall bhp/torque. Maximum torque on the EV-1 was reduced through cam profile and, most importantly, compression ratio reductions.
Yes, an advantage to the 4-6K rpm range can be realized by directly replacing the 2.0 liter cylinder head with the 2.1/2.3 design but even better results at this same rpm range can be seen by a properly updated 2.0 liter cylinder head design.
We do not wish to suggest that there is only one way to do things with respect to cylinder head updating and our analogy has always been "if you're happy and content with the results relative to an enhancement, stay with it".
Best of luck to you and regards!
GSK @ SWEDISH DYNAMICS,INC.
posted by 64.12.96...
, Thu, 9 Jan 2003 02:24:57
, Sun, 5 Jan 2003 16:32:20
, Sun, 5 Jan 2003 19:58:03, Thu, 9 Jan 2003 22:28:11
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