More input from Larry and Bill C. 10/13/98 (see below)
Discussion about exhaust systems and fuel valves for the Lyc IO540
From: JOHN HARLOW <jharlow@okeechobee.com>
To: jerico@sierratel.com <jerico@sierratel.com>
Subject: exhaust sys
Date: Friday, October 09, 1998 4:42 PM
Any thoughts on the exhaust sys avail. I'm building a series 90 with a IO540 and would like a equal length set of headers. John
From: jerico <jerico@sierratel.com>
To: John Harlow jharlow@okeechobee.com
Subject: Re: exhaust sys
Date: Saturday, October 10, 1998 8:59 AM
Good morning John,
Thanks for the email. Good to hear from you and that you are "building".
I believe you should be able to get the "tuned" exhaust system from Larry Olson at Express Aircraft Co. He also will custom build if that is what you want.
You could also check with Glasair as they use 540's in the III. Their
web address is on my web page.
I also will include Bob Gisburne in this email as he is flying the 540
and may have an idea.
Bill Copeland. Any ideas other than the above suggestions?
Cheers, Jerry
CC: Also to Larry Olsen.
From: Gisburne
Subject: Re: exhaust sys
Date: Saturday, October 10, 1998 7:15 PM
John:
I have an IO540C4B5 and modified a set of Glasair III exhaust. I have an
original EDI cowl (with the triangular inlet openings) which is not as
deep as the new EDI/Express Aircraft cowl. Thus I had to modify them. I
saw N90ED at Copperstate today. It looked like they had been able to use
Glasair exhaust, un-modified.
I have been happy with the performance of the exhaust. Spectators like
the sound of the engine... perhaps the augmentors help??
As far as performance... I'm still experimenting. My airplane is a
little slow compared to some. I true out at 170kts while I understand
N90ED gets 180+kts. I still need finish paint etc. My point is that I'm
not sure if the expense of the Glasair exhaust (~$800???) is justified.
The exhaust that came from EDI was a joke... a stainless erector set with
about 25 clamps to hold it all together!
Hope this helps! Bob
N4382A
CT converted to S-90
From: JOHN HARLOW
To: gisburne@neta.com <gisburne@neta.com>
Subject: Re: exhaust sys
Date: Sunday, October 11, 1998 4:07 AM
Thanks for the information. I presently have the Auriga cowl but Larry has
promised me an early set of the new cowls with slightly adjusted round inlets
for improve clearance on the front cyls. I thought Larry only supplied 3 into 1
sys for each side. From my days of hot rodding I know how important equal length
(tuned) pipes are. Room is an issue though.
As an added note to Bill Copeland, I have installed Andiar fuel valves. They
make a 5 port valve which allows each tank to feed separately (valve not listed
in any catalog) and then I feed to a on-off valve also by Andiar. Very clean
set-up and positive position sensing.
from: Gisburne to: Dr.@box.okeechobee.com
Subject: Re: exhaust sys
Date: Sunday, October 11, 1998 8:12 AM
John:
I recently installed an Andair valve as well. I did not opt for 4 tanks,
but rather just two. The Andair works VERY well as you indicate. I
mounted mine right between the from seats. Re-routing the lines was a
chore, but well worth the efforts. I think there is a picture of the
valve on Jerry's web page. Click here for the picture
John: what fuel servo are you planning to use on your IO540? I have the
RAS-5? servo... Larry said they recently installed the RAS-10 which is
standard on a 300hp Glasair install. I'm thinking maybe I'm not getting
enough air to the engine. My servo diameter is about 2.5" vs 3.8" for the
RAS-10.... I guess that why they call it experimental...
Bob (Gisburne)New below (10/13/98)
John:
Reading the discussion re: Tuned exhaust, I think you got all the relevant info about the normal sources, but, being an old "Hot Rodder" myself, it occurred to me that the automobile performance engine people probably know more about the subject than aircraft people do. You might want to check with your local speed shop or a header manufacturer - you might learn something for all of us.
Thanks for the clue re: the Andiar fuel valve. Could you possibly find and forward advertising copy or a pic of your installation together with information as to where the valve can be acquired. I think the info would be a great article for the EXPRESS Link.
Bill C. (Copeland)
John
Just remember when you go to design a tuned exhaust system for your
Express. Space is extremely limited under the cowling. In order to get all
tubes at an equal length you are either going to have the cross the rear
cylinders under the engine or bring them forward and back to the rear. When
you do this you have to be careful not to run exhaust close to the fuel
injection throttle body.In addition you have to keep the exhaust away from the cowling and miss the nose gear shock strut and throttle and mixture cables. If you run it forward you have the starter and alternator to worry about. In addition, you will have to support the exhaust system or the vibration of the long pipes will cause them to crack. Once you have all
this worked out then you are going to have to figure out how you are going
to accommodate for all the extra heat that is radiated into the engine
compartment by the long exhaust stacks. Hot Rodders don't worry about this.
When all is said and done you will probably have to enlarge your cowling
which will create more drag and eat up all the horsepower you have created
with the tuned exhaust.
Larry Olson
