Exhaust Sizes
#1
Exhaust Sizes
I'm looking into exhaust upgrades for the 07- UP XKR's.
Only published dimensions I'm finding are the following:
Milltek
2.25" Sport Cats (Assuming O.D)
2.36" Cat-Back
Paramount Performance Cat-Back:
?
Quicksilver:
2.1" I.D
These are the only ones I have located currently. Does anyone know of a manufacturer that is fabricating 2.5-3" Cat-back systems?
Per my engineering knowledge and fabricating history with race cars, The 2.36" Cat-back system would be a little restrictive if my goal is 500-hp.
I'm currently building a 2.5" 200 Cell Cat kit, that will lead into a 2.5" X-pipe. The plan is to venturi out to 2.75"-3", depending on supplied kits or fabricate my own.
Any input is appreciated.
Regards,
D. Fricke
Only published dimensions I'm finding are the following:
Milltek
2.25" Sport Cats (Assuming O.D)
2.36" Cat-Back
Paramount Performance Cat-Back:
?
Quicksilver:
2.1" I.D
These are the only ones I have located currently. Does anyone know of a manufacturer that is fabricating 2.5-3" Cat-back systems?
Per my engineering knowledge and fabricating history with race cars, The 2.36" Cat-back system would be a little restrictive if my goal is 500-hp.
I'm currently building a 2.5" 200 Cell Cat kit, that will lead into a 2.5" X-pipe. The plan is to venturi out to 2.75"-3", depending on supplied kits or fabricate my own.
Any input is appreciated.
Regards,
D. Fricke
#2
exhaust sizes
I recently bought a 2013 xkr from a woman who is an engineer that was often on this site.
she designed her own exhaust. I acknowledge her to be the expert on exhausts, considering that the car I bought put out 680 hp at the rear wheels, on a dyno.
The car has a scream to it that I have only heard from cars that cost 350,000 dollars and higher
I also consider her an expert at engine modification and aerodynamics.
She posted as "SoCal Babe".
I encourage you to look in the archives for pics and the specs of tubing size and other details that will help you
she designed her own exhaust. I acknowledge her to be the expert on exhausts, considering that the car I bought put out 680 hp at the rear wheels, on a dyno.
The car has a scream to it that I have only heard from cars that cost 350,000 dollars and higher
I also consider her an expert at engine modification and aerodynamics.
She posted as "SoCal Babe".
I encourage you to look in the archives for pics and the specs of tubing size and other details that will help you
#3
Md_plasticss......Do you have proof to back up those claimed dyno numbers?
I also would like to see alot more input into this thread, im currently in the process of building an all 2.5" 304 SS exhaust system from the manifolds back. Started making the X-pipe today, I will post pics as the project progresses. All ive been able to find from the few others that actually list the pipe size is already listed in the first post here. I believe the Spires stage 1 is 2.25" as well but dont hold me to that.
I also would like to see alot more input into this thread, im currently in the process of building an all 2.5" 304 SS exhaust system from the manifolds back. Started making the X-pipe today, I will post pics as the project progresses. All ive been able to find from the few others that actually list the pipe size is already listed in the first post here. I believe the Spires stage 1 is 2.25" as well but dont hold me to that.
#4
Thanks for the input.
bigdhenderson, 2.5" Is a good approach. Depending on your end goal of hp, I would consider at least this diameter. Which is approx I.D. 2.37" I.D. in 16 gauge.
4.41in^2, which should flow about 507 CFM or 1014 CFM for 2 pipes.
The rule of thumb is you need approx 2.2 CFM per HP for exhaust.
Standard steel pipe assuming standard frictional losses will flow about 115 CFM per in^2.
Other piping options:
2.75" 16ga I.D. 2.62" or 5.39 in^2, flow about 620 CFM or 1240 CFM for 2.
3" 16ga I.D 2.87" or 6.46 in^2, flow about 742.9 CFM or 1485.8 CFM for 2.
Since my end goals will be to push close to 600-650 bhp Im going to build the rear from 3", the cat system will consist of 2.5" and run into a 2.5" x-pipe center. I will then venturi from 2.5" to the 3" rear.
For a stock motor setup, the supplied Milltek, quicksilver and other systems seem to be okay. For those that are upgrading pullies etc, anything smaller than 2.5" may be a little restrictive.
I'll look forward to seeing your photos. I'll post some up of my cat system next week.
bigdhenderson, 2.5" Is a good approach. Depending on your end goal of hp, I would consider at least this diameter. Which is approx I.D. 2.37" I.D. in 16 gauge.
4.41in^2, which should flow about 507 CFM or 1014 CFM for 2 pipes.
The rule of thumb is you need approx 2.2 CFM per HP for exhaust.
Standard steel pipe assuming standard frictional losses will flow about 115 CFM per in^2.
Other piping options:
2.75" 16ga I.D. 2.62" or 5.39 in^2, flow about 620 CFM or 1240 CFM for 2.
3" 16ga I.D 2.87" or 6.46 in^2, flow about 742.9 CFM or 1485.8 CFM for 2.
Since my end goals will be to push close to 600-650 bhp Im going to build the rear from 3", the cat system will consist of 2.5" and run into a 2.5" x-pipe center. I will then venturi from 2.5" to the 3" rear.
For a stock motor setup, the supplied Milltek, quicksilver and other systems seem to be okay. For those that are upgrading pullies etc, anything smaller than 2.5" may be a little restrictive.
I'll look forward to seeing your photos. I'll post some up of my cat system next week.
The following users liked this post:
bigdhenderson (11-24-2014)
#5
#6
The following 2 users liked this post by bigdhenderson:
FrickenJag (11-24-2014),
Panthro (11-27-2020)
#7
Didn't have much argon left so tacks are pretty brown, will be grinding them off and purging when final welding is done. Then a full sanding and polishing for the nice seamless look.
The pipes are so close together I'm a little concerned about proper flow through the x-pipe I made, I wish someone had the dimensions and location of the xkrs/aftermarket x-pipes
The pipes are so close together I'm a little concerned about proper flow through the x-pipe I made, I wish someone had the dimensions and location of the xkrs/aftermarket x-pipes
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#8
This is a photo of the XKR-S pipe section below.
You are merging closer to the trans and I would feel this is a better approach than the XKR-S System. Typically, the rule of thumb I've used with hotrod / race car projects is to mount the x-pipe as close to the trans as possible.
You want the x-pipe positioned in the exhaust where you still have pulsing and scavenging effects. So you are at the ideal location.
I'm attempting the same with my setup.
Attached are some options on mounting depending on size of muffler (18.5 x 4") in photo. I'm opting to do as minimal bends as possible and have decided on the 150 deg approach in "Exhaustdim2" pdf.
Regards,
D. Fricke
You are merging closer to the trans and I would feel this is a better approach than the XKR-S System. Typically, the rule of thumb I've used with hotrod / race car projects is to mount the x-pipe as close to the trans as possible.
You want the x-pipe positioned in the exhaust where you still have pulsing and scavenging effects. So you are at the ideal location.
I'm attempting the same with my setup.
Attached are some options on mounting depending on size of muffler (18.5 x 4") in photo. I'm opting to do as minimal bends as possible and have decided on the 150 deg approach in "Exhaustdim2" pdf.
Regards,
D. Fricke
The following 3 users liked this post by FrickenJag:
#9
Hi Chaps,
Very intetested in this thread as i'm in the process of having a custom center section made for my 2010 XKR out of 2.25" pipe. I was going to get the shop to do a direct copy of the XKRS center section with X pipe........intetested on your point about the X pipe position......so closer to the front of the car the better or is there an optimal position? Also what about the entry/exit intersection of the x pipe? Is 90deg optimal? A
so intetested to know how it effects the exhaust note........a very interesting thread has been born!!!
Very intetested in this thread as i'm in the process of having a custom center section made for my 2010 XKR out of 2.25" pipe. I was going to get the shop to do a direct copy of the XKRS center section with X pipe........intetested on your point about the X pipe position......so closer to the front of the car the better or is there an optimal position? Also what about the entry/exit intersection of the x pipe? Is 90deg optimal? A
so intetested to know how it effects the exhaust note........a very interesting thread has been born!!!
#10
I recently bought a 2013 xkr from a woman who is an engineer that was often on this site.
she designed her own exhaust. I acknowledge her to be the expert on exhausts, considering that the car I bought put out 680 hp at the rear wheels, on a dyno.
The car has a scream to it that I have only heard from cars that cost 350,000 dollars and higher
I also consider her an expert at engine modification and aerodynamics.
She posted as "SoCal Babe".
I encourage you to look in the archives for pics and the specs of tubing size and other details that will help you
she designed her own exhaust. I acknowledge her to be the expert on exhausts, considering that the car I bought put out 680 hp at the rear wheels, on a dyno.
The car has a scream to it that I have only heard from cars that cost 350,000 dollars and higher
I also consider her an expert at engine modification and aerodynamics.
She posted as "SoCal Babe".
I encourage you to look in the archives for pics and the specs of tubing size and other details that will help you
#11
Hi Chaps,
Very intetested in this thread as i'm in the process of having a custom center section made for my 2010 XKR out of 2.25" pipe. I was going to get the shop to do a direct copy of the XKRS center section with X pipe........intetested on your point about the X pipe position......so closer to the front of the car the better or is there an optimal position? Also what about the entry/exit intersection of the x pipe? Is 90deg optimal? A
so intetested to know how it effects the exhaust note........a very interesting thread has been born!!!
Very intetested in this thread as i'm in the process of having a custom center section made for my 2010 XKR out of 2.25" pipe. I was going to get the shop to do a direct copy of the XKRS center section with X pipe........intetested on your point about the X pipe position......so closer to the front of the car the better or is there an optimal position? Also what about the entry/exit intersection of the x pipe? Is 90deg optimal? A
so intetested to know how it effects the exhaust note........a very interesting thread has been born!!!
I too will be working on this modification next. Want to replicate the XKR-S exhaust center section, retain stock muffler set up but remove stock tips and add Mina tips given to me by a very generous fellow member TBerg. My goal is simple, to get a better sound and look without spending a fortune.
Knowing if there is a way to improve this part before I begin would be great!
Bob
The following 2 users liked this post by GrtShrk:
bigdhenderson (11-24-2014),
damienedwards (11-24-2014)
#12
Perfect pictures Bob......very useful to see those renderings.
i'm now debating to move the x pipe nearer to the front of the car to go where the first silencer is......my cars going in for the work on the 22nd of December.........need some informed input.......or i may just go for it!!
Need to engineer a way to be able to slide the X pipe along the center section!!
i'm now debating to move the x pipe nearer to the front of the car to go where the first silencer is......my cars going in for the work on the 22nd of December.........need some informed input.......or i may just go for it!!
Need to engineer a way to be able to slide the X pipe along the center section!!
#13
#14
The following 2 users liked this post by GrtShrk:
bigdhenderson (11-24-2014),
Panthro (03-10-2016)
#15
GrtShrk or anyone can you answer this. Some rear boxes made by performance exhaust manufactures have no valves that open or shut to create more noise. Number 2 on the pictures are the valves one each side of the original . When these are not used are the air pipes blocked or just left open.
The picture i show is a quicksilver system and has no valves, so if fitted the old valve pipes would not be used, so would it be better to block them or leave open.
The picture i show is a quicksilver system and has no valves, so if fitted the old valve pipes would not be used, so would it be better to block them or leave open.
#16
#17
This is a photo of the XKR-S pipe section below.
You are merging closer to the trans and I would feel this is a better approach than the XKR-S System. Typically, the rule of thumb I've used with hotrod / race car projects is to mount the x-pipe as close to the trans as possible.
You want the x-pipe positioned in the exhaust where you still have pulsing and scavenging effects. So you are at the ideal location.
I'm attempting the same with my setup.
Attached are some options on mounting depending on size of muffler (18.5 x 4") in photo. I'm opting to do as minimal bends as possible and have decided on the 150 deg approach in "Exhaustdim2" pdf.
Regards,
D. Fricke
You are merging closer to the trans and I would feel this is a better approach than the XKR-S System. Typically, the rule of thumb I've used with hotrod / race car projects is to mount the x-pipe as close to the trans as possible.
You want the x-pipe positioned in the exhaust where you still have pulsing and scavenging effects. So you are at the ideal location.
I'm attempting the same with my setup.
Attached are some options on mounting depending on size of muffler (18.5 x 4") in photo. I'm opting to do as minimal bends as possible and have decided on the 150 deg approach in "Exhaustdim2" pdf.
Regards,
D. Fricke
Is that a 1st gen (65-66) mustang roof line, I spy there?
#18
#19
The following users liked this post:
bigdhenderson (11-25-2014)
#20
Just posted this in another thread but it may be worth putting in here too...
Is the performance active/XKR-S back box also different to the standard XKR? I've read a couple of times now that just replacing the centre section and secondary cats with an X-Pipe actually seems to make the standard exhaust more refined on the XKR/XFR; slightly louder with a different tone, but stops the pops/bangs on the over run, this is the opposite of what I'd expect to happen?!
I'm weighing up options for a new exhaust on my XKR at the minute, I was thinking about just doing the X-Pipe, but I wouldn't bother if it meant loosing the popping etc as I think that's part of the fun.
Is the performance active/XKR-S back box also different to the standard XKR? I've read a couple of times now that just replacing the centre section and secondary cats with an X-Pipe actually seems to make the standard exhaust more refined on the XKR/XFR; slightly louder with a different tone, but stops the pops/bangs on the over run, this is the opposite of what I'd expect to happen?!
I'm weighing up options for a new exhaust on my XKR at the minute, I was thinking about just doing the X-Pipe, but I wouldn't bother if it meant loosing the popping etc as I think that's part of the fun.