Jon The Caddy you're referring to was the 4-6-8, a V8 with an electrically actuated MECHANICAL device which allowed or prevented actuation of some intake valves. The electronic system I was referring to is essentially a solenoid on each valve, i.e. no cam or rockers or pushrods. It's my understanding that some of the grand prix cars use this now. Talking to a Ford guy at an engineering show ~1990 he said that solenoids "used too much power" so there was no net gain. I thanked the guy and went elsewhere 'cause I know fertilizer when I hear it.
There is also a "variable valve timing system" which consists of hydraulic lifters with a calibrated leak. Low RPM the oil bleeds out & you get reduced lift, high RPM less oil bleeds out and you get more lift. Wear is an obvious problem, along with noise and mushrooming the valve stems. Bill -----Original Message----- From: GTS-1000 Owners List [mailto:[EMAIL PROTECTED]] On Behalf Of Crisler, Jon Sent: Tuesday, December 24, 2002 10:59 AM To: [EMAIL PROTECTED] Subject: Re: Airbox mods Actually, different length/diameter intake runners are fairly common now in cars, sometimes with valves that shut down one intake at low speeds. I have tuned runners in my lowly Ford Contour with the V6, which is actually a quite spunky littlecar. As for electronic valve actuation, a form of this design actually made it into a production Cadillac sometime in the 80's, known as the V4-6-8. At low power, only 4 cylinders had the intakes operating. Obviously, something was flawed in the design, as I think it lasted 2-3 years and they dropped it. -----Original Message----- From: wghalley [mailto:[EMAIL PROTECTED]] Sent: Monday, December 23, 2002 11:02 PM To: [EMAIL PROTECTED] Subject: Re: Airbox mods Nick Less air flow at low RPM due to airbox restriction won't make more torque. The way to make more torque at low RPM is to increase the air velocity, which requires smaller intake manifold, ports and valves, all of which restrict airflow at high RPM and hurt top end power. Essentially you get a ram air effect tuned for low RPM. Restricting the airbox is the same as putting an orifice plate in the intake. This will give you a pressure drop due to the decrease in air flow. This will decrease the charge pressure in the cylinder (because there's less of it) which has about the same effect as reducing the compression. What you can do is have two different size intake runners & valves, a small one and a big one. They work like the old spread bore 4 barrel carbs - small primary and huge secondary. This is part of the Caddy Northstar design. If you could combine this with variable valve timing you'd have what you want. Best hope is electronic valve actuation - which is being studied (for the last 15 years) but hasn't made it into production. Bill -----Original Message----- From: GTS-1000 Owners List [mailto:[EMAIL PROTECTED]] On Behalf Of nicholas.threader Sent: Sunday, December 22, 2002 5:02 PM To: [EMAIL PROTECTED] Subject: Airbox mods Hi all , Has anyone altered their standard airbox to flow slightly more air , i've used S&B filters for some time but they seem to flow a bit too much air in low to mid-range , so i've switched back to the standard box , now my bike feels like it could do with a bit more air from mid-range up . Maybe a tuneable airbox ? less flow at low rev's to give torque and more flow at high rev's to give power , am i barking up the right tree with my way of thinking ? I'm looking at altering the 2 rubber intakes that are stuck on the sides of the airbox . atb Nick T Happy Christmas to one and all . --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.431 / Virus Database: 242 - Release Date: 17/12/2002 The information contained in this e-mail including any attachments may constitute Corvis Corporation Proprietary Information that is subject to Non-Disclosure Agreement and cannot be disclosed to any other party without the express consent of Corvis Corporation. If you are neither the intended recipient of this e-mail nor responsible for delivering this e-mail to the intended recipient, note that any dissemination, distribution, copying, or retention of this e-mail is prohibited. If you believe you have received this e-mail in error, we request that you notify the sender by return e-mail and then delete this e-mail and any return e-mail immediately.
