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| Joined: | 03-14-2005 |
| Location: | Atlanta, Georgia USA |
| Posts: | 406 |
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One issue we didn't discuss was the total valve overlap. You get more overlap when using the 110/110 timing which should equate to more top-end power at the expense of low-end torque.
However, switching to 115/115 forces the exhaust to open earlier and the intake to close later. Both of these conspire to reduce low-end torque as well. Kind of a damned if you do, damned if you don't delima. The 110/110 is really the lesser of the two evils.
We could discuss theory until the cows came home or just try it and see. With stock pistons I honestly don't think you'll see much difference either way. Without a dynamometer, g-meter, etc. it would be difficult to quantify any real changes. If it ain't broke, don't fix it!
Next time you shim your valves, my advice would be to install a 107 cam from the club store on the exhaust side and run 110/110 timing. If budget permits, buy a second 107 for the intake side. Drivability and low-end performance will increase with each upgrade.
If you ever do replace the pistons as part of a full rebuild, also invest in a set of later Lotus HTD sprockets with 104/104 timing (i.e. 'green dot' version). The higher c/r pistons will be able to take advantage of the increased overlap for a boost in top-end performance.
Judson