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Posted: Wed Nov 05, 2008 7:53 pm 
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Jaysen wrote:
backpressure is a falacy, exhausts work on velocity and waves, and its as simple as you said it. Lower pressure in the exhaust will encourage cylinder scavenge and initial filling. The thing here is that normally anything apart from WOT is going to mean that your exhaust is at a higher pressure than the intake, and even at WOT, there is enough boundary effect from the intake manifold runners to create a lower pressure at the intake port.

See Scientific design of intake and exhaust systems for further clarification, its a book that most will need to read several times to understand what they are on about, I know that I did.



i've got that, read it twice from front to back and still went back through some sections for a third go.

there are alot of people on here that could learn alot from that book!

 

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Posted: Wed Nov 05, 2008 8:09 pm 
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yeah that's the same one I was reading at uni...the bit i found craziest to understand was about the design of the intake to best take advantage of the pressure waves at different rpm's

i knew physics was useful for something!

 

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EVL098 wrote:
Cramping in the hand from having it on your Wang for an excessive period of time is a definate con.
Seriously do people google "f**k up modifications for Fords owned by Jews" and get linked straight to this site nowadays?

AU,factory fitted tickford kit/IRS, t5,Sports ryder/KYB: gone.

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Posted: Wed Nov 05, 2008 8:18 pm 
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skidder wrote:
yeah that's the same one I was reading at uni...the bit i found craziest to understand was about the design of the intake to best take advantage of the pressure waves at different rpm's

i knew physics was useful for something!


get a copy of engine analyzer pro3.3 and start playing with some of the ideas.

i cam up with a very different set of extractors for the I6 a while back.
i'd almost put money on people from this site telling me it wouldn't work,

some times still wish a had the car and the money to do it.


Jaysen might recall the ones i'm talking about.

 

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Posted: Wed Nov 05, 2008 8:53 pm 
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tickford_6 wrote:
some times still wish a had the car and the money to do it.


I know, so far I have built 2 engines for my mates but not a single one for myself (annoys me that they have all the money and are sh*t drivers too 8-) ).

I had that on my old computer but that was before i really understood anything...haha, seeing as I'm avoiding uni work atm I might as well start mucking around with it again

 

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EVL098 wrote:
Cramping in the hand from having it on your Wang for an excessive period of time is a definate con.
Seriously do people google "f**k up modifications for Fords owned by Jews" and get linked straight to this site nowadays?

AU,factory fitted tickford kit/IRS, t5,Sports ryder/KYB: gone.

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Posted: Wed Nov 05, 2008 9:49 pm 
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cool engine analyser pro 3.3 eh now thats info i can use i am assuming i cant just download it off the net so where can i buy the software

 

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Posted: Wed Nov 05, 2008 10:13 pm 
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i found it the program is made buy performance trends oh if only i had a brand spanka computer and a credit card i'd go nuts buying those programs be on the computer for hours screwing around learn s**t loads to

 

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Posted: Wed Nov 05, 2008 10:58 pm 
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gogetta wrote:
I have been hearing this for years (decades) and I believe its just a typical jump on the band wagon mentality...

I have not seen any scientific proof that a big bore exhaust looses low down torque...

from my experience all it does is give u more top end....


and i also by implication it does not destroy your bottom end torque

have a look at a set of pacmakers they have 3" flange on them...aftermarket cats are easy to get in 3" so why then downsize the rest of the system....u might as well run 3" all the way....

 

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Posted: Thu Nov 06, 2008 12:20 am 
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EA Pro is a good program, but you have to remember that s**t in = s**t out, and therefore cant be taken as gospel. Look around, and you can find a hacked verison of it, but its not easy to find. One of my pet hates is having to pay numerous times for the same program to be run on different computers. I dont mind paying for software, dont get me wrong, but if they really wanted to sell it, then sell it once to the consumer and Im sure that they will be happy to recomend others to just buy it, and not rip it off the net. My GUI tuning software TunerPro is like that, as is VM Ware, both great programs, and both I recomend all to have if your needing that style of software.

I do remember having discussions with you Tickford6 about your header designs, Im sure that you may have sent it to me to run on my version of EAP, but that software has long since gone due to formatting, and hence the setup files with it.

 

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Posted: Thu Nov 06, 2008 10:31 am 
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gogetta wrote:
and i also by implication it does not destroy your bottom end torque

have a look at a set of pacmakers they have 3" flange on them...aftermarket cats are easy to get in 3" so why then downsize the rest of the system....u might as well run 3" all the way....


just remember that a 3 inch cat might only have the flow of a piece of 2.25 inch straight pipe.

Pacemaker 4480
Primary Pipe:
1 ⅝"
(41mm)
Secondary Pipe:
1 ¾"
(44mm)
Outlet (flanged):
2 ½"
(63mm)

Pacies do not have a 3 inch flange if you team them up with a 3 inch cat you need to cut them back a few inches and weld on a new flange at the 3 inch diameter mark.

the idea is to keep flow rates up. a fast flowing cat, and straight through single chamber mufflers would be a better port of call than increasing the size of your pipe that far. Its not a v8, its only 4 litres, and only revs to ~5500 rpm. the ricers only use 3 inch pipe to get better spool up, due to a hi pressure on one side of the vanes, and low pressure on the other. having 3 inch pipe after a 3 inch cat would see low rpm air speed drop after the cat, as it is restricted and slowed, and then fed into a low pressure chamber.

just to put it into context about mass and velocity, a 6 litre V8 revving to 6500 rpm will need the exhaust capacity to move 39,000 litres of air a minute (on paper, reality differs slightly with gass expansion, sacavenging, and residual deposits). a 4 litre 6 revving to 5500rpm needs to move 22,000 litres of air a minute. which is almost half!

Im not saying 3 inch is bad, just size the pipe for where you want it to be most efficient, and thus make its power. size it to your mods. Biggest is not always best.

I garauntee you, get a stock falcon on a dyno, then put on a 3 inch and dyno it again. there will be a small hole in the torque on the graph early on.

 

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Posted: Thu Nov 06, 2008 1:45 pm 
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well finding the program was easy but working out hw to use it properly is a hole different story but i having fun with it

 

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Posted: Thu Nov 06, 2008 8:51 pm 
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Jaysen wrote:
EA Pro is a good program, but you have to remember that s**t in = s**t out, and therefore cant be taken as gospel. Look around, and you can find a hacked verison of it, but its not easy to find. One of my pet hates is having to pay numerous times for the same program to be run on different computers. I dont mind paying for software, dont get me wrong, but if they really wanted to sell it, then sell it once to the consumer and Im sure that they will be happy to recomend others to just buy it, and not rip it off the net. My GUI tuning software TunerPro is like that, as is VM Ware, both great programs, and both I recomend all to have if your needing that style of software.

I do remember having discussions with you Tickford6 about your header designs, Im sure that you may have sent it to me to run on my version of EAP, but that software has long since gone due to formatting, and hence the setup files with it.


i lost my EApro the same way. voxace had the crack for it, need to try and find it again.
i spent hours and hours fine tuning a stock EF engine in ea pro untill the projected power curve was within a few HP of the real thing, then back checking through specs to make sure it was 'right'.
i then spent a few more entering data to 'build' the engine i had running in my XR6, the one i ran in the 14s with your R1 cam. had that one within a few HP aswell. it even had the power curve after 5000rpm pretty much the same as the dyno showed on the real engine.


as for the pipes, if anyone has the time and money, build a set with 2inch primary pipes 40inches long into a pair of 3into1 merge collectors
with 2 1/4 inch secondaries 12inches long into a single 3inch system.

 

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Posted: Thu Nov 06, 2008 8:59 pm 
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Grimketel wrote:

Pacies do not have a 3 inch flange if you team them up with a 3 inch cat you need to cut them back a few inches and weld on a new flange at the 3 inch diameter mark.



I wouldn't personly cut back the collector at all. I'd run about 2inches of 2.5 inch pipe and then use a 2.5 to 3inch cone that is about 3 to 4 inches long to take it up to 3 inches (would be better to have this about 25inches long), and have about 6inches of 3 inch pipe befor joining into the cat. I'd also make it the biggest (internal volume) cat that will fit under the car.

 

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Posted: Thu Nov 06, 2008 9:34 pm 
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autospeed did the exhaust up on a EF falcon.
links below;

http://autospeed.com/cms/A_108185/article.html

http://autospeed.com/cms/A_108186/article.html

cheers......

 

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Posted: Thu Nov 06, 2008 10:55 pm 
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EL__Fairmont wrote:
autospeed did the exhaust up on a EF falcon.
links below;

http://autospeed.com/cms/A_108185/article.html

http://autospeed.com/cms/A_108186/article.html

cheers......


they say on the second page they are tuned length, but the picture doesn't look like they are...is it just the angle of the pic?

 

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EVL098 wrote:
Cramping in the hand from having it on your Wang for an excessive period of time is a definate con.
Seriously do people google "f**k up modifications for Fords owned by Jews" and get linked straight to this site nowadays?

AU,factory fitted tickford kit/IRS, t5,Sports ryder/KYB: gone.

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Posted: Thu Nov 06, 2008 11:28 pm 
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I am running the same 2.5in Mercury tailpipe as shown in the pic with a Lukey Race series muffler upfront with a high flow cat and pacemaker 4499's. Really nice deep growl.

Image

 

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97 EL Fairmont 4l OHC .Silver.
Exhaust: Pacemaker's, 2.5" exhaust and Hiflow cat
Intake: FRAM AIRHOG , EL GT snorkel
XR6 300kpa fuel reg Stg 2 Auto Shift Kit.6DJA ECU
PM in Qld looking too buy Toyota 4*4 SR5 Dualcab Hilux 91-97 with 2.8l diesel engine/5spd manual

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