We have performed a rear muffler delete on our restoration XJ12C.

Sounds fabulous. More noise outside, but no extra noise inside.

While we were mocking up the pipes we had straight pipes coming out of the back. It looked pretty good, and would have looked even better with some nice chrome tips. However, we cut the pipes and refitted the curved tailpipes because we had a feeling that they were there for a reason. Fellow member smgdata thinks its to keep exhaust fumes out of the car (by channeling the exhaust into the slip stream and away from the car)

I know early S1s had straight tailpipes, but they became curvy pretty soon after.

Any insights from anyone ?

 

Yeah, that is the history of the curved pipes.


I've seen and heard of a car or two that used straight out
pipes. But, no word of "stink in the cabin".


In this day of closed windows, heater or AC on, any adverse
effect seems limited.


Added to that, the rear seat in most cases is rarely occupied.,
so migration of exhaust to the fronts seems limited.


Carl

 

I notice less fumes and it is quieter... of course the Jag tips are smaller OD. PO had even welded up the exhaust holes... I put on a new rear valance panel and the muffler shop modified the exhaust to allow the tips to fit.

My next exhaust change will be to run the rear section under IRS like a Corvette.. did it to my old '72 XJ. Only this time instead of flanges I will use stainless V clamps.

But, I like the looks and sound!

 

Under the IRS is going to be interesting
when you do it because of pipe placement.

So I'll subsribe right now

 

I wonder if they moved them outward to reduce the likelihood of burning or soiling your trousers when accessing the trunk... oops, I mean the boot.

 

Nope...as has already been said, it's to do with avoiding the ingress of exhaust fumes where you definitely don't want them.

 

Thank you gents. We will leave as is for now

 

I used 1988 XJ-40 straight tips for a while and the car became faster, just kidding, but I did not get any exhaust fumes inside the cabin or trunk/boot or anything. I think it was a matter of design, how the car looks, looking for a way to make it look different, that kind of stuff.

UPDATE: I just installed the XJ-40 tips again, I really like the way the car looks with either the "S" tips or the straight tips, can't make up my mind so I just use one set for 6 months, and the original set the other 6 months. What the heck.

the tip's inside diameter is 1-7/8" inch on all Jaguars.

 

Dangerous to assume there is no heightened risk by interfering with exhaust management. Carbon monoxide is the killer, its emission is insidious in nature being both invisible and odourless.

 

Hi Sarc,

Anything that oozes class is necessary

Cheers,

Nigel

 

@Nigel

Agreed, and the coupes have quite a lot of that going on. I am happy with the rear muffler delete, and the original curvy pipes.

 

Some things are just right in some places and not so in others. chrome exhaust tips is one!!


Dual exhaust has been in my "system" since the early days, late 40's!!!! Harder to achieve then. Limited bucks and no tube benders.


I cobbled a pair for my 4 banger T "Hot Rod". Cut a hole in the
manifold up front. handy Unc welded in a pipe and a flange. Can't weld CI? He didn't believe it.


Stock pipe with extension on the passenger side. Flex across the car and out the driver side. Mufflers? No $'s available. Not bad....


Did a similar thing to my hotted 46 Mercury powered 37 Ford "Q" ship. Made some "mufflers from pipe. Small pipe laboriously drilled
with many small holes inserted into a larger pipe. Cavity stuffed with steel wool and swarf from a machine shop.Encds closed over with plumbing caps. bigger hole in each laboriously made, small ppes connected to exhaust on each end. Voila, heavy duty "Smitty's".
Lotta drone and back rap. Acceptable at the time????


I got cat back systems for my Cordoba and F150. No tips, just plain pipes. Purposeful....
No change in noise whatsoever, Better breathing? I doubt it.
Just looked right!!!!


Jaguar came with "curly" tips. Welded on by PO!!! No problem,
they look right. and with V8 power, they sound right!!!


Not nosy, just a nice burble....



Carl



F

 

Can i ask what made you decide on the rears versus the fronts?

 

I'M confident the curved pipe was employed to eliminate a particular exhaust resonance.

The resonance or sound of any piped system is dependent on pipe length and diameter...think pipe organ. The length of a pipe matters even if its curved. One way to change the resonance of a pipe with out making it effectively longer is to put a s bend in it.

Futhermore, it commonly known the longer the tail pipe the quite the system and since Jag's are quiet it makes sense the engineers used this trick to lengthen the tail pipe.

 

Interesting, indeed. But, the increased length added by the curve seems such small part of the whole. Not to mention the 1 becomes 2 scheme!


But, yes, the duals on my 312 powered 57 1/2. exited in front of the rear wheels. Longish Mitchell glass packs. It could be loud.


I was having trouble with an early "stove style" four barrel. so, the dle was a tad high to avoid stalling. Oh, oh, got nailed in an LAPD "safety inspection". All good, but pipes too loud! A mechanical thing that any cop could sign off on.


So, I added glass packed tis and tuned down the idle. Passed!!!


I like that organ pipe analogy. Just watched a thread here on CanAm cars of the 60's. Got the other machine to communicate with my sound!!!


Awesome, 8 "organ" pipes !!!!


Carl

 

PS:


Short ones, right up off the headers!!!


Carl