2-stroke excel for ports, heads and pipes [Archive]

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JanBros

19th November 2019, 06:31

My 2-stroke spreadsheet is ready (for now at least), so I'm throwing it on the net so everybody can use it.
It contains pages for ports, the head and FOS pipe
On the seperate ports pages (exhaust and transfer), it calculates the STA numbers (Specific Time.Area) of your ports and you can matcch them to the target's, determinned by the BMEP
On the Head page, you can design your head and it calculates the MSV (Mean Squish Velocity) 100% accurtly with Blair
On the FOS-pipe page, it calculates a Frits Overmars FOS pipe, and you can ad a Wobbly-duct , and you can add extra header/diffusor/baffle sections to the pipe.

you are free to do with it what you want, as long as it is not for commercial use. If somebody has idea's to improve or add extra features, please share so we can all benefit.
In the manual I've tried to explain how it works, please read it first before you ask questions.
If somebody has any idea of how to print a portmap to correct size, please let me know, as I don't have a clue right now.

http://users.telenet.be/jannemie/JanBros%20%202-stroke%201.0.jpg
excel : http://users.telenet.be/jannemie/JanBros%202-stroke%201.0.xlsm
manual : http://users.telenet.be/jannemie/JanBros%20%202-stroke%201.0.docx

Frits Overmars

19th November 2019, 09:39

My 2-stroke spreadsheet is ready (for now at least), so I'm throwing it on the net so everybody can use it....you are free to do with it what you want, as long as it is not for commercial use.
excel : http://users.telenet.be/jannemie/JanBros%202-stroke%201.0.xlsm
(http://users.telenet.be/jannemie/JanBros%202-stroke%201.0.xlsm)manual : http://users.telenet.be/jannemie/JanBros%20%202-stroke%201.0.docxBravo Jan :clap:! I know that it has been a tremendous amount of work.
I noticed that you refer to my 'Leaning Tower of Pisa' story. If you wish, you can download the complete Pisa-story from https://drive.google.com/drive/folders/18l2ShH-MzrnTO0uEk9rNTk89_KgwgWof , from the folder 'FOS Tips & Concepts', and bundle it with your masterpiece.
In fact, you can use everything you find there and use it, provided credits are respected.
You might also take a look at the disclaimer accompanying the 'FOS Exhaust Concept'; it is a bit more extensive than the older version that you quoted.
:niceone:

husaberg

19th November 2019, 15:06

Great stuff

JanBros

20th November 2019, 09:10

apparently I seem to make the same mistake over and over : I keep forgetting the variable for the FOS pipe is speed of sound and not exhaust gas temperature. It had no effect on the workings of it all, but I've corrected it now in the manual and the spreadsheet and uploaded corrected versions ;-)

koenich

21st November 2019, 19:19

what an effort! thanks for making it available for everyone! :banana:

AndreasL

30th December 2019, 03:19

Have played around with your excel along side EngMod the last days and I can say its a great complement. :niceone:

You mentioned above that you uploaded a updated version of the program with corrected units (C° and m/s that I always get mixed up :brick:)...

...but cant find or see any new or different file compared to the initial one.

Just want to know so I haven't missed anything and that the version I have work as intended. So far, my hand calculations say its all ok but you never know.

Thanks again for great work!

Edit: If its not to much to ask...but the option for a straight header in the pipe section would be great. *wink wink*
I can add it my self, but your layout skills beats mine by far so... :)

JanBros

6th January 2020, 05:22

aparently there was an error in a BMEP-link in my 2-stroke excel, fixed it now.

and now there is a way of printing the portmap to actual size, so you can print it, cut out the ports and place it in your cylinder to see where you have to grind the ports some more.

anyone used it already ? any comments ?

I can'y edit my openings-post ? would be better to have the latest download links in there.

new download links to version 1.1 :
excel : http://users.telenet.be/jannemie/JanBros%202-stroke%201.1.xlsm
manual : http://users.telenet.be/jannemie/JanBros%20%202-stroke%201.1.docx

(http://users.telenet.be/jannemie/JanBros%20%202-stroke%201.1.docx)

AndreasL

7th January 2020, 01:37

Not tested the "Print"-function yet, but I like the idea.

Can see that you updated the C° vs m/s as well. Good.

Have thought about the straight header of the FOS pipe combined with a Wobbly duct and realized that this might be something that ain't considered wise at all? Have to ask Frits what he thinks and the most logic approach to a set up like that. Hmm...

Thanks again for your time putting this program together. Its a great help.

When adding all zeros to i.e. the aux port data, I have an error (########) in "Data" for both the total exhaust as well as the BD total. In both tables.
If adding a small value, like 0.1, to one off the port width cells, it seems to work. At least no errors than.
If that was a bit hard to understand, ask and I will try to explain better when not in a hurry.

JanBros

7th January 2020, 10:40

Sorry, I seem to have mist/forgotten your request for straight headers.
but you can easily do it within the program as it is now : use the 2 (or 3-) stage diffuser, in which you can adjust all dimensions with the sliders.
all the way to the belly, the diameters can never be lower than the previous one, so just slide all the D-headerS to the minimum and they will have the same diameter as the spigot. only thing that is missing is that you have to add both length's together to get the length of a single header/diffuser/baffle. But you can easily make 3 cell's for that.
than if you don't want a staged diffusor SHOWN THE GRAPH, just change the the diameter of Diffuser-1 so that the cone-angles of diffuser-1 and -2 are the same and you have one big diffuser . And you can do the same with the baffle.

I haven't touched any of the port-pages, only repaired BMEP on the exhaust old page as that wasn't working.
for your zero's, you'll have to give me an example, as it's not quite clear to me where you are entering the zero's.

JanBros

7th January 2020, 23:38

they are the flow direction in the horizontal plane of the mixture/exhaust gases going through the port.

for the transfers and auxiliaries, they are the dotted lines you can switch on and off the in the circular graph on the transfer pages.

they depend largely on the directional angles (the full lines on the same grap) of the ports, and the curve the transfer tunnels make (A port to the front in the RSA, whch means the leading is more important, B port to the back, making the trailing more important).
You'll have to make an educated guess of the angle.

JanBros

12th January 2020, 12:36

another small error has come up : on the Data page , in cell Q14 both "exhaust new" should be "exhaust old" , so change it yourself or download it again in my previous post

AndreasL

13th January 2020, 00:49

Great JanBros!
That took care of one of the issues I encountered.

My problem still persist in the 'Data' - 'Port Areas effective flow'-table if adding only “0” to the 'Exhaust Old' - 'Port Map Data Aux'-table. (To simulate a single port exhaust.)
This gives empty cells in “Y20” and “Y23” thus an error in the Total Exh (“Y21”) and Total Bd (“Y24”) calculations. My workaround so far has been to add a small value to any of the “Aux Port Data”-cells resulting in “0” instead of empty spaces in i.e. “Y20”.
The same thing for 'Exhaust New' obviously.

Edit: Think I found it! Since the Total Tr sum is correct regardless of the number of ports used, I looked in to that formula. For the Total Tr a “SUM(xx:yy)” is used. For the exhaust ports above a addition (+) of the cells is used. Changing this to “SUM...” as per the transfers gets rid of this error and no need for the workaround mentioned above anymore. :)

JanBros

14th January 2020, 01:31

you'd better leave all cell's from port's you don't use blank : it's much easier to spot that you have left them all blank and no "left-overs" can influence calculations. I do it that way. just copy an entire blank colum in aux portmap from below and you'll see that automaticaly all aux cel's on the data page will be blank to.

AndreasL

14th January 2020, 07:03

Aha! Great!
Then I was misinterpreting your instructions.
Good to know.

The error caused by using addition instead of “SUM” for the total Exh and Bd values in 'Port Area Effective Flow’, like for the transfers, is still a reality though. Zeros or blank cells in the port maps does not matter in my (old) version of excel.
It would be interesting to hear if any one else gets the same result (error), making a single port exhaust. If not, then it’s most likely just me and I can stop taking your time with “non issues”.

Absolutely no criticism of your extremely thorough work.
And I have been able to solve my issues.
But if any one else, having the same problems as me, can get help from it I’m more then happy.

JanBros

14th January 2020, 07:48

think I've got them all now Andreas, some extra 'IF's where needed, and some zero's way down out of sight instead of #NB's

also added a printable page you can take into your shed where you can write down all the needed input-data on, so now it's 1.2 :

excel : http://users.telenet.be/jannemie/JanBros%202-stroke%201.2.xlsm
manual : http://users.telenet.be/jannemie/JanBros%20%202-stroke%201.2.docx

AndreasL

14th January 2020, 22:45

That sounds VERY useful!

Thanks again for sharing all this work in such unselfish manner.

I will have a look at 1.2 later tonight. I hope...

casal-fan

20th January 2020, 05:17

JanBros, did you forget to pay the server bill??? Or is it maybe just my Win7 running firefox browser thats not up to the task...
Have noticed the program for some time ago, but was gonna give it a look this evening, but the link just returns "not found"

By the way, having had my fair amount of goes at calculating sheets on excel, congratulations, and thanks man. Must have been a mammut task:clap::clap::clap:

Edit: now working, keeping the post for the congratulations and thanks part. It´s worth it

Jefferym

15th March 2020, 16:35

Says link not found can you help?

My 2-stroke spreadsheet is ready (for now at least), so I'm throwing it on the net so everybody can use it.
It contains pages for ports, the head and FOS pipe
On the seperate ports pages (exhaust and transfer), it calculates the STA numbers (Specific Time.Area) of your ports and you can matcch them to the target's, determinned by the BMEP
On the Head page, you can design your head and it calculates the MSV (Mean Squish Velocity) 100% accurtly with Blair
On the FOS-pipe page, it calculates a Frits Overmars FOS pipe, and you can ad a Wobbly-duct , and you can add extra header/diffusor/baffle sections to the pipe.

you are free to do with it what you want, as long as it is not for commercial use. If somebody has idea's to improve or add extra features, please share so we can all benefit.
In the manual I've tried to explain how it works, please read it first before you ask questions.
If somebody has any idea of how to print a portmap to correct size, please let me know, as I don't have a clue right now.

http://users.telenet.be/jannemie/JanBros%20%202-stroke%201.0.jpg
excel : http://users.telenet.be/jannemie/JanBros%202-stroke%201.0.xlsm
manual : http://users.telenet.be/jannemie/JanBros%20%202-stroke%201.0.docx

JanBros

17th March 2020, 10:15

I can not edit my opening post.
you must use the links a couple post above yours ;-)

Jeffrey28

18th April 2020, 16:42

Jeffrey28

18th April 2020, 16:50

I appreciate uploading link again thanks

JanBros

19th April 2020, 20:53

read the entire topic, they are still working. not those in the first post though.

Vannik

20th April 2020, 07:14

The ones in post #18 still works.

TZ350

20th April 2020, 09:33

mr bucketracer

25th April 2020, 17:22

This is really good work. Thanks.hey tz . What did the port timing of your stort stroke bucket engine end up been .just building my one

TZ350

25th April 2020, 21:38

hey tz . What did the port timing of your stort stroke bucket engine end up been .just building my one

Shortened Suzuki crank to 48mm stroke and NSR250 54mm bore. Packed up the barrel to get transfers opening 116 deg ATDC and that positioned the exhaust opening at 80 deg ATDC without any additional porting required.

The shorter 48mm stroke has the effect of increasing the blow down time area on the NSR cylinder that originally had a 54mm stroke. As the short stroke crank needs to turn a lot more degrees to get between Ex opening and Trans opening.

We did this conversion with a basically stock Suzuki GP100. A little later closing on the Rotary valve (80 deg ATDC). Used the original Suzuki GP carb and inlet tract. Honda RS125 NF4 pipe. Made a strong 25 RWHP. With another engine (my EFI bike) and a lot more work (and much more crankcase volume) we have managed a good 30 RWHP.

mr bucketracer

26th April 2020, 08:25

Thanks for that . Mines even shorter stroke again but good to see ratio difference From standard Nsr to yours . Just need to find that now

TZ350

26th April 2020, 12:14

Thanks for that . Mines even shorter stroke again but good to see ratio difference From standard Nsr to yours . Just need to find that now

Suzuki GP125 Bore 56mm stroke 50mm ratio 1.12: 1. RGV250 twins were the same bore 56mm stroke 50mm. It was popular at the time.

NSR MC21 Bore 54 stroke 54 Ratio 1:1

De stroked Suzuki GP with NSR cylinder Bore 54mm stroke 48mm ratio 1.12:1

So these hybrid 110cc engines have the same bore/stroke ratio as the original Suzuki GP's. Which proved to be not ideal but has worked well enough.

CARBONX2

3rd May 2020, 01:30

JanBros

On the FOSpipe page, if I click to remove the Wobbly Duct selection from the 3-stage diffuser, the tuned length reduces a lot. Is it because I have updated all engine details?

JanBros

3rd May 2020, 21:23

Hi,

you probably did not touch the sliders ?
the stage 3 pipe (when downloaded) shown is not based on the calculations, but by me adjusting the sliders to get the dimensions of the Tubo102 correct so the comparison to an original FOS-pipe is visible.
so if you did not touch the sliders, your calculated stage-3 is also done based with the sliders well of the charts.

to get them back, re-adjust them so that the yellow cell's under % (of length) are back 100%, resulting in the stage 3 having the same length as the original FOS. if you then click on the Wobbly you'll see the total length stays the same.

CARBONX2

3rd May 2020, 23:14

Thanks
Yes, I haven't touched the sliders yet

JanBros

4th May 2020, 06:21

I'm re-working some things at the moment (forgot the piston-pin diameter), so if anybody has some requests , now is a good moment ;-)

Javier Ruda

6th May 2020, 01:08

I'm re-working some things at the moment (forgot the piston-pin diameter), so if anybody has some requests , now is a good moment ;-)

Hello JanBros, this is my first post. I have been reading and reading and reading for a long time as a guest, now as a member. First of all big thanks to you, Frits Overmars, Jan Thiel and all the engine tuners that contribute here.

Your Excel file has helped me A LOT to understand the theory, since it is a very good summary of the knowledge of the forum.

I have good skills with Excel and its associated Visual Basic. As i am confined at home, not working now, please let me know if you need help to further develop your file.

Wos

11th June 2020, 09:02

Hey jan,

In the Moment i am working with your fantastic Excel! :)

New for me bore 54 x 54,5 stroke are 247,82 capacity ? :)...and msv is very high too
...think a tiny Misstake. .. :)...page
Head Design... when using Input from data ...without any changes...

Thank you for heaving a quick look on it :)

Grüße Wolfgang

JanBros

14th June 2020, 10:57

Hi,

tnx for your kind words.
ever wondered why people write manuals ? The writers do hope you read them before you ask questions :msn-wink: a lot of time goes in writing them, and I'll be the first to say it's not perfect, but I still think there is a lot of good info in it.
copied from it :

 Ticking this box :

will make all the light green input cell’s meaningless, as all those parameters will be taken from the DATA sheet.

if you look at "data new", you'll see that it's a 66.2/75 B/S engine, not a 54.5/54

Wos

15th June 2020, 00:44

Thanks jan for support and clarification! :)

And if you allow me another question to pipe Design

Surley your remember frits words to the restrictor size... depends on if a engine is thermally sound or not...

On the underdogracing calculator there was the possibility to choose between air and watercooled. ..

In our case the aircoolde factor for the restrictor of a aircooled classic enduro worked perfektly :)

Do you remember what the factor was? ;)

It could help us for a thermal unsound minarelli 75 cc conversion to watercooled. ..with poor and small radiator

Thank you very much jan!

Grüße Wolfgang

JanBros

15th June 2020, 12:08

don't know what it was on the (I believe it was) underground site.
For my mopeds I use +/- factor 1.7. FOS says 6.9mm, I use 12mm.

Wos

17th June 2020, 08:43

Thanks for your help jan! *top*

The underdog calc was not supported or approved by frits. ..right jan ;)

1.7 seems to be a lot. ..a advice with a lot of safety... ;)

However ...we have to test whats sound for our specific engine...and gives us power :)

Grüße ! Wolfgang

JanBros

17th June 2020, 19:08

I don't think Frits will approve any calulator ;-)

testing the nozzle for power will probably result in the same nozzle as a "thermaly sound engine" : a too small nozzle that could overheat your "thermaly not-sound engine" .

I did test different diameters and chose one big enough that didn't lose too much power. I didn't say 1 .7 is a general rule, it's what I use for my MX-moped.

Wos

17th June 2020, 20:23

2 stroke tuning is always and everywere tecnical gambling ;) like it jan! ;)

Frits Overmars

19th June 2020, 22:50

I don't think Frits will approve any calculatorThere are two main reasons.
The first reason: suppose I make an adjustment in my concept, for example in the size of the restrictor diameter. This has already lead to various calculator versions that contradict each other on the internet. And because these calculators use the FOS name, I may be held responsible for things that are beyond my control.

The second reason: some calculators offer multi-stage diffuser or reflector options that were not included in my exhaust concept and for which I cannot take responsibility.
I recommend to keep things simple anyway. Fiddling with multi-stages before you have neared to an optimum means extra work which will slow your development down.

JanBros

20th June 2020, 21:25

That's why I said it Frits, and I include the picture with your concept, so people know the version :msn-wink:

Wos

21st June 2020, 05:36

Condyn

22nd June 2020, 11:26

Hi, I have built a set of FOS pipes with 3 stage diffusers utilizing the JanBros spreadsheet. I enjoy everything about it so far, including the price. I donated these pipes for dyno work, and against the proper design, the team that received them insisted I use a fixed 23mm stinger. Currently working on a personal set that will be done properly. Just want to give a thanks to everyone who has put a great deal of work into making this happen. 346206

Wos

12th July 2020, 10:13

Hey frits, hello jan :)

My fellow and i made a pipe now, using the Excel. ..3 stage diffusor. ..2 stage baffle. ..

And you both go to jail if it dosent work propperly :p :)

Little joke!
Thanks for your work...pleasure to use it!

Maybe in about two weeks there is the rollout of the 75 cc minarelli :)

Grüße! Wolfgang

To give your some Feedback ;)...and say thanks to you!!! :)

Jan. ..frits...the spreadsheet lead us to new Dimensions in bulding pipes...:eek5:

Rollout today...the minarelli k6 has a unbeliefable broad useable band of power...7000 to 11500...peak set in speadsheet to 10000...75 cc... 18 hp...phenomenal for enduro use:hug:

Grüße Wolfgang

JanBros

9th February 2022, 23:05

another smal error reported by a member.

The error is in cell P19. It refers to the percentage of the 2 stage diffusor in cell M18
but it should refer to cell R19, which is the percentage of the 3 stage diffusor.

change it yourself or download a new version

http://users.telenet.be/jannemie/JanBros%202-stroke%201.2.xlsm

JanBros

27th August 2022, 21:42

NEW DOWNLOAD LINKS due to dissapearance of webpage :

excel 1.2 : https://www.dropbox.com/s/704mkuizswtd038/JanBros%202-stroke%201.2.xlsm?dl=0
doc 1.2 : https://www.dropbox.com/s/kthd5k7nntidg8u/JanBros%20%202-stroke%201.2.docx?dl=0

jonny quest

13th September 2022, 12:54

Very nice work!

I just downloaded latest link. Instructions say there's a 250 MX engine data. I only see 2 125s. Did this change? I'd like to see the 250 data and what it was from (make/ model/ year)

JanBros

25th October 2022, 05:38

due to a new post from Frits : https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/page2494

I made a small correction to the calculation of the target Bd and transfer STA to get the correct target-value spot-on again with the new BMEP of the RSA

excel 1.2.1 : https:// (https://www.dropbox.com/s/lng9du2bxfic02e/JanBros%202-stroke%201.2.1.xlsm?dl=0)dl.dropboxusercontent. (https://www.dropbox.com/s/kthd5k7nntidg8u/JanBros%20%202-stroke%201.2.docx?dl=0)com/s/lng9du2bxfic02e/JanBros%202-stroke%201.2.1.xlsm?dl=0 (https://www.dropbox.com/s/lng9du2bxfic02e/JanBros%202-stroke%201.2.1.xlsm?dl=0)

(https://www.dropbox.com/s/kthd5k7nntidg8u/JanBros%20%202-stroke%201.2.docx?dl=0)
doc 1.2 : https://dl.dropboxusercontent.com (https://www.dropbox.com/s/kthd5k7nntidg8u/JanBros%20%202-stroke%201.2.docx?dl=0)/scl/fi/1nd418esc40e76r8xrcbc/JanBros-2-stroke-1.2.docx?dl=0&rlkey=cy9a7q74h74oy48633s5yj8e1 (https://www.dropbox.com/s/kthd5k7nntidg8u/JanBros%20%202-stroke%201.2.docx?dl=0)

https://dl.dropboxusercontent.com/s/laspqd4zy21eo2d/JanBros%20%202-stroke%201.0.jpg?dl=0

(https://www.dropbox.com/s/kthd5k7nntidg8u/JanBros%20%202-stroke%201.2.docx?dl=0)

(https://www.dropbox.com/s/kthd5k7nntidg8u/JanBros%20%202-stroke%201.2.docx?dl=0)

JanBros

28th October 2022, 06:55

another small error reported, which caused the exh port width to be a little too low.
corrected link in post above

husaberg

28th October 2022, 17:55

another small error reported, which caused the exh port width to be a little too low.
corrected link in post above

Thanks for making this available, I appreciate the work that goes into this and the selfness nature of sharing it.

JanBros

26th December 2023, 01:53

small Christmas present, I've changed my FOS-exhaust page, so it includes the header and diffuser %'s, and some other changes.
excel : https://greentrade.international/Janbros/JanBros2-stroke2.0.xlsm
doc : https://greentrade.international/Janbros/JanBros2-stroke2.0.docx

and a stand alone Exhaust, which has an extra exhaust-comparator sheet
https://greentrade.international/Janbros/FOS_PIPE_3.0.xlsm

Pursang

26th December 2023, 02:26

Thank you for your efforts.
Merry Christmas and have a great 2024.:2thumbsup

SwePatrick

21st March 2024, 01:24

JanBros

21st March 2024, 23:56

It seems like your program is calculating wrong when trying to make a head.
Known bug?

I can´t point at specific problems as it seems there are a lot.

anything is possible, but you would be the first .
and without something specific, it's hard to look for it.

JanBros

2nd June 2024, 06:31

new links as of 1-06-24 since the other site is down

excel : https://dl.dropboxusercontent.com/scl/fi/3pvcei60h9pzysn9kksjd/JanBros-2-stroke-1.2.3.xlsm?rlkey=s8aqw3u2ir1wi49nig6lkap2h&st=90e3iewd&dl=0
doc : https://dl.dropboxusercontent.com/scl/fi/1nd418esc40e76r8xrcbc/JanBros-2-stroke-1.2.docx?rlkey=cy9a7q74h74oy48633s5yj8e1&st=8dmk16js&dl=0

and a stand alone Exhaust, which has an extra exhaust-comparator sheet
https://www.dl.dropboxusercontent.com/scl/fi/o60fnwy0juw3dug0hnvdr/FOS-PIPE-3.0.xlsm?rlkey=x3krlbq8ybzzowrd4fz8ozs2b&st=0vgjxfr4&dl=0

JanBros

20th July 2024, 22:40

new link as of 20-07-24 due to update of Frit's FOS concept :

excel : https://dl.dropboxusercontent.com/scl/fi/ln8om2082vxe2s1846rgz/JanBros-2-stroke-2.1.xlsm?rlkey=4rubscgnbo5ew3vr29u95n7wo&st=1wakchjk&dl=0
doc : https://dl.dropboxusercontent.com/scl/fi/1nd418esc40e76r8xrcbc/JanBros-2-stroke-1.2.docx?rlkey=cy9a7q74h74oy48633s5yj8e1&st=8dmk16js&dl=0

and a stand alone Exhaust, which has an extra exhaust-comparator sheet
https://www.dl.dropboxusercontent.com/scl/fi/xfa6z1f538xdvbfq7ir3v/FOS-PIPE-3.1.xlsm?rlkey=1vvacku7nu4ebktlfckvmz2u4&st=3jwq49jo&dl=0

JanBros

21st July 2024, 21:55

new link as of 21-07-24 due to update of Frit's FOS concept and a small error in the calculation of "Deck-Aux Open" calculation which had no effects on the STA's:

excel 2.2 : https://dl.dropboxusercontent.com/scl/fi/kkrtwe77k1k0l29ue6m1c/JanBros-2-stroke-2.2.xlsm?rlkey=xoauprgm0rhwklrr24mkbi7gq&st=g69206c6&dl=0
doc 1.2 : https://dl.dropboxusercontent.com/scl/fi/1nd418esc40e76r8xrcbc/JanBros-2-stroke-1.2.docx?rlkey=cy9a7q74h74oy48633s5yj8e1&st=8dmk16js&dl=0

and a stand alone Exhaust, which has an extra exhaust-comparator sheet
FOS 3.1 https://www.dl.dropboxusercontent.com/scl/fi/xfa6z1f538xdvbfq7ir3v/FOS-PIPE-3.1.xlsm?rlkey=1vvacku7nu4ebktlfckvmz2u4&st=3jwq49jo&dl=0