I'm betting the H-Pipe located closer to the end of the collector
will be most effective.

Since the pressure pulses are stronger at the collector, rather than
a couple of feet down the system, the draw on either exhaust bank
will be more pronounced.

As for installing a dual 3" system (or larger), I wish to retain the
mid range scavenging for street use. Going to a large volume
exhaust system would benefit my track data, but not as fun for
the drive home.

I'm going to look into the mufflers you have suggested, as well
as tuning a pipe length directly off of the collectors for racing.

 

A little update for those interested. What would this post be without a little
practical application anyway!?

I took the advice of many here, as well as some tips from "the book".

With the addition of twin 2 1/4" x 2.5' pipes bolted directly to my collectors,
I have now changed the attitude of my engine.

It's MUCH quieter. As a comparison, with my previous setup, I could not hear
the tires burning out, nor the flex fan and cam gears over the exhaust. The stereo was pretty
much a $400.00 LED clock until this weekend!

The new setup now has long tube headers, with 2 1/4" x 2.5' pipes, followed by
single chamber "purple hornies".

My throttle response from idle has surprisingly improved. Without tuning the
carburetor accelerator pump cam, or nozzles, the car seems to squirt off the
line much faster.

I wont be able to confirm this mental feeling of acceleration without a visit to
the track, but so far, the longer exhaust length seems to help.

The mid to top end acceleration is difficult to quantify. It sounds slower, but
it seems to move forward quite nicely when dropping from 3rd to 2nd from an
80 Km/H roll (~50 MPH for the yanks )

I would think the top end will suffer with the extra length (shorter pipe = tune higer RPM). Does anyone make a pipe that retracts as engine RPM rises?

My next plan is to grab 2.5" pipe and run it back to a set of Magnaflows.
I checked out the fabrication of Magnaflow; nice and straight through! I
didn't realize the pipe extended straight through the can.

A quick estimate leads to five feet of 2.5" pipe to each muffler, then about
two feet of exit pipe after the mufflers.

These pipes will be capped with cat. covers and kept as straight as possible to rear of the vehicle.

Next year will be an expensive test of mathematics, physics and theory.
I'm hoping that some of you can confirm the exhaust lengths and muffler
position when I get around to trying the formulas found in Dr. Morrison's book.

 

Almost finished the book! Been a slow read, but well worth the buy.

Pg. 180, "Multi Cylinder Experiments" talks about Crankshaft phasing.

He mentions 90 degree and 180 degree crankshafts. What does this mean?
I'm thinking the bank angle of the cylinders (Flat 8 = 180 crank, V form = 90 degree crank).

Never heard of this (nor a flat 8 for that fact). He also mentions phasing these
cranks at said degree?

Next question: Single Plane and Two plane crankshafts?

Single plane for in-line engines, and two plane for V forms?

 

Just diifferent terminology used to describe the same thing. A 90º crank (two plane) has the pins 90º from each other as viewed from the crank snout. Where as a 180º has all the pins in-line 3 o'clock and 9 o'clock... however you want to look at it. 180º aka "single plane" crankshaft.

A picture

-Mindgame

 

Here's a link to a "flat crank" discussion in Advanced Tech.



http://web.camaross.com/forums/showt...7&page=1&pp=15

 

Thanks for both the picture and link. Back to the books

 

Just when you thought this thread was dead...

I'm planning for this season, and I'd like some confirmation please and thanks.
All the specs are next - the questions are at the end of the post!


I'll be shopping for some headers, and mufflers for the 1980 Z28.
Here she is:
http://www.rudyhelds.com/Customer_Ri...Camaro_Z28.htm

In addition to the above, I now have a Comp Cams 292H-10 camshaft,
3 angle valve job, 0.010" and shaved from the heads.

Cam specs @ 0.006

IVO 40 ____ IVC 72
EVO 80 ____ EVC 32

106 centerline
110 LSA
0.334" lobe lift, 244 degrees @ 0.050"

I will be grabbing new valve springs (Comp Cam PN# 986-16) and Comp Cam's
Pro Magnum roller Rockers (PN#*1302-16C) to raise the valve into more of the head's
flow range. (0.534" valve lift).

The heads are World Products Sportsman II, 72 c.c. (iron casting).
http://www.sallee-chevrolet.com/Worl...nII_Heads.html

Flow Data (?)
http://purplesagetradingpost.com/sum...ld%20Sportsman

My last power curve made 270 HP at the wheel @ 5800 RPM with a Crane 284-H12 camshaft.

Dynojet Graph:
http://members.rogers.com/tdese739/images/dynograph.jpg

The car went 13.2@105 MPH, 1.99 sixty, 3761 lbs., street tires.

Now for the reason of the post - Headers!

According to my math, I'll need a header primary that is min. of 37.5".

Primary length (ft.) = 244 * 3.48 * ( 4.030 ^2) /1,400 * (1.75^2)
= 849.12 * 16.2409 / 1,400 * 3.06
= 13 790.473 / 4287.50
= 3.216 ft. (37.5 inches)

I have been looking at the following:
http://www.hedman.com/pages/hedmanmain.html
(not sure)
http://www.holley.com/HiOctn/ProdLin.../f2455HKR.html
(2466HKR 2466-1HKR)
http://www.holley.com/HiOctn/ProdLin...SFT/FThdr.html
(31100FLT)

With all of the above 'smokescreen data', what headers do you recommend?
This is a weekend summer car which will see some drag racing. For the most
part, it's a loud obnoxious cruising car.

What will fit nicely in the engine bay of a 1980 Z28?

For the remainder of the system, I'd like to use 2.5" piping (reduced from 3" after the H-pipe) straight out to the rear.

I am leaning toward Magnaflow straight through 2.5" mufflers. This will be a
'true dual' system. I don`t care about sound level, or interior noise. I want
flow for power.

Thanks for reading all of this!
Tino

 

To be resonant, an exhaust primary would need to
be five feet long, at 5000 RPM, something similiar
for the intake.
That said, 30 inch headers, are useful, but not resonant.

 

Five feet @ 5000 huh ?

What rate are you using for velocity of sound? Is that a full length wave?

EDIT: Cut out. Sounds sarcastic.