Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Intake developments. Porsche vs. Yamaha

I find this post most interesting. But, I had to raise an eyebrow when the spark plug wires where mentioned. The plug wires sit directly on top of the engine mount bushing cap don't they. The reason I mention this is because when I had my car dyno tested, I couldn't help but notice just how much the engine moved under acceleration. If you place this channel between the two runner ends, it may torque the entire intake system when the car is under acceleration. This new channel would act like a torque bar, and when the engine moves under acceleration, it would catch on this motor mount, which when combined with the torque jerk of the engine, will act like a prybar ... not good. I would check and double check clearance issues!

Chris,

Looks like he's a little busy today.. He
pointed me to the shotimes forum to his old
posts...(his experiment was inconclusive as
he never did get to dyno the car, but maybe
the book can help point you in the right
direction)

Here's one...

As a little late night reading, I picked up a book called 'Design
Techniques for Engine Manifolds'. On page 183, they show an intake
manifold geometry not unlike the SHOs. They go through a long
description of how to make the engine perform better. How? You know
the cross-over that connects the front to back plenums that supports the
DIS. The suggestion is to close that passageway at low and high rpms,
and leave it open in the midrange for improved torque. The book has an
example that shows how this boosted low end torque and high end power by
10-15%. Not too shabby....so.....

Since I don't have access to a valve to slip into this passage way, I
did the next best thing. Yep, taped off the crossover so that the front
and rear plenums can not communicate (don't try this at home unless you
are brave). The results so far? Geez. It's hard to say...got to give
it a bit more time but my initial impression is that there is more
torque right around 3000-3200 rpm and less at 4000-5000 rpm.

Now the low/high rpm stuff, that is a bit more challenging to
characterize as it happens so quick or we so seldom drive at this rpm.

High rpm: I can't tell for sure..maybe a little more but I've already
got the LPM & 80 mm MAFS.

Low rpm: It doesn't have much pull, but I'm not sure I remember how much
pull my car had there.....it's not like we drive our SHOs at 2000 rpm
too often. I'll keep my car plugged for awhile longer and report back
if anything becomes more clear.

Sound: Hmmm...Something is definitely different here. I can't quite
put my finger on it, but the engine sounds quite a bit different. The
point of sealing this crossover is to make the intake manifold act like
two independent 3 cylinder engines...I don't ever remember envying the
sound of the Geo Metro coming out of the intake. You'll notice a
distinct and immediate difference before the secondaries open up in
terms of noise, after the secondaries open, it sounds just like your SHO
does today.

Just a thought for anyone who gets their SHO on a dyno with more than 1
run. To cap off the ends requires bolting the crossover back down (as
this is how the DIS is grounded) but this is still a 5 minute change
with a generous helping of duct tape (careful people, don't want to
scrape 3M off your pistons). This really needs analysis on a dyno.

The real story is that you probably won't be happy with just leaving the
cross-over plugged as it will drop torque somewhere in the middle, but
if the benefits are there as predicted, a valve that switches with rpm
in this crossover could boost low-end torque & power.

A downside? The SHO's long crossover length, makes this connection
between plenums a little less effective at boosting mid range torque so
the effect may not be as dramatic as predicted. With that said,
consider that the new Jaguar 3.0L engine utilizes at least 2 of these
communication valves between the plenums to perform some additional
tuning tricks.

While the Yamaha engineers who designed this engine might roll their
eyes at this mod, I'd bet not, certainly Ford might've been a little
concerned to allow them to add another valve in this passage to boost
power above that of the beloved Mustang GT back in '89. Just a thought
for the ever-experimenting.


BTW, Chris, I believe he does have the
patent around somewhere. If it gets into my
hands, I'll get it to you ASAP.

Quote from the big bro...

based on my posting another member found a series
of Yamaha patents on this and rekindled my interest. I have a copy of it.
It is from 1988 or 1989 I believe.

[This message has been edited by pornstar* (edited May 02, 2001).]

Sandman, that patent (6209510) deals with a new piston/rod technology that appears to move the top section of the piston as the rod moves. I snagged the TIFF's and will put them on my website. The IP changed so I need to do it when I get home.

http://crush7.dyndns.org/piston/

This thing got me into thinking about changing my major from EE to ME again!






------------------
AirKnight (Dominic Ho)
Buffalo, NY

AIM: AirKnight on MTB

My BEAST

Patent search ...

http://www.delphion.com/

Ok Chris-

That is not what I am doing with my idea. My idea changes the piston motions/position/acceleration (all for the better) for a given crank angle/RPM. I have a few technical articles here that demonstrate the principles that I am basing my idea off of, and they appear to be very promising. They did not eliminate the wrist pin, however, or change any of the conventional design parameters of the piston/rod like what I have in mind.

I think you will be able to run higher compression ratios without fear of detonation with what I am doing.

Of course, this would require a complete tear down of the engine. Not fun.

------------------
95 Contour SE automatic, 37,000 miles

Chris-

Also, did you look and see how close the valve covers are to those freeze plugs? This would be an extremely tight fit, unless of course we could get some type of phenolic spacer made that would raise the upper intake plenum? What then about hood clearance?

Would it be possible to use the signal from the IMRC system to control a butterfly valve in the crossover? This seems to be RPM/Load/Throttle position dependant. Maybe an experiment to see if it should be open or closed based on the position of the secondaries?

Also, while I am playing 20 questions, what does IIRC stand for? (Newb here, I know)

------------------
95 Contour SE automatic, 37,000 miles

IIRC = If I Remember Correctly

------------------
Michael Amisano
1998 SVT Contour E1 5785 of 6535, Black 'n' Blue
Mods: MSDS Y-Pipe
Receiver: Kenwood CD HeadUnit w/5v Pre-Outs and Sub control, Speakers: Polk DB 6 1/2" Seperates in Front, 5 1/4" in Rear, 10" SAS Tube,AMPS: Sony 50x4, Sony 75x2 @ 200x1 Radar Detector:Valentine One
New Engine: 09/00 @ 42K Thank You Extended Warranty!
Waiting for Install: MSDS Headers, Granatelli 75mm MAFS, Conical K&N Filter
mamisano@optonline.net

The freeze plug location being close to the valve cover shouldn't be a problem. Looking at the SHO engine, the flow of air between the banks can be a sharp, 90 degree turn. The passage I was thinking of making would be narrow and tall, and have seperate pieces to go in the freeze plug location. I am thinking as long as there is some air going between the banks at certain RPM's we should see some kind of performance increase. The guy with the SHO said he dyno'ed his V6 with that passage closed up, and he lost lots of HP except around 3800 RPM's. So, a butterflyvalve would close around 3800 and open back up around 4200? I'm thinking the valve would operate independatly of the secondaries. Dyno'ing would be the best way to figure out RPM open/close points. My first guess at the valve schedule, based on the SHO's performance would be as follows:

Open: 0-3699 RPM
Close: 3700-4099 RPM
Open: 4100+ RPM

Manually controlling the valve while on a dyno would be best. Either that or a cable or something in the cockpit while you are driving, just for testing purposes

We'll see!


IIRC- "If I remember correctly"

I've always like thermodynamics