I had posted this in the XJS section and realized I probably should have put it here. People frequently wonder how their V12 will sound without catalytic converters and resonators, so I made this video. Just light rev's of the engine to 4000 rpm.

 

Hi, here is a sound of my sold V12 XJS with AJ6 substitute pipes & stainless steel mufflers + modified air aspiration (blast sound level of your computer...)

 

I've never been keen on the 'no' or 'busted' exhaust sound, but the second video of the black XJS sounds sweet.

Quiet enough to tickle along in traffic, and lets you know that there is some meat under the bonnet when giving it some.

Would have loved a video of it pootling around the Arc de Triomphe at around 6am, if it would stick to the cobbles.

 

I'm not running completely exhaustless. I still have the factory mufflers on it, I just removed the cats and secondary mufflers/resonators. Under normal driving it sounds quiet, but step on the gas and it roars!

 

On this car I also had modified the air intake (fresh air from under front bumber) bigger butterflies and AJ6 ECU modified.

 

Nice work!

 

Thank you

Here is the other side.



I had to make a 80 mm hole in the internal wings and add an other "boa" to the hole behind the flasher lamps. The stuff is hidden by the plastic surrounding in wings.



This car was quite reactive and fast....

 

I've been trying to think of the best way to run the plumbing for a cold air and that looks like the easiest route. Did you have to cut a hole by the bumper?

 

A question for both of you guys with modified exhaust: Any "booming" resonance at certain speeds/engine loads? Especially steady highway speed, 60-75 mph?

This is the age-old bugaboo with low restriction exhaust.

I like the sound of both, BTW :-)

Cheers
DD

 

Right around 3500-4000 rpm there is a significant "boom" on mine. However, I rarely experience it unless I'm using heavy acceleration. Under normal driving I can't reach 3500 rpm and keep it under the speed limit.

 

@JameyXJ6: There is a built in hole behind the front flashers.

I had a significant "boom" at 3000 RPM witch was tiring on long journey on highway (around 130 km/h: max legal speed here)
There was no cats on this car originaly...

If you do the job, don't forget that you have to modify the place where there are some relays and amplifier(passenger side) and some wire from fan (driver side). Easy to do

!!!!! But first of all: The throttle sensor must be in perfect condition if you want to have a perfect running car....check the current voltage at iddle position (engine stopped but ignition on) There is inside a round copper 'lan' and a cursor moving on it (potentiometer): most of time this is damaged on most used position (20 years) and it gives wrong info to the ECU.(sorry for my vocabulary, it is not simple to explain as it is not my native language)
It is possible to find one at AJ6 engineering (UK) or like I lucky did on ebay (OEM)
I will tell you how to do it later, I am not at home.

Edit: I am back home,
I found this sentence on AJ6 web site:
"Throttle position sensors eventually wear out as they age and are a common cause of vague and erratic drivability problems, such as hesitation and flat-spots during acceleration."

With a tester, you should find 0.32v on the 3 wire conector but I can't remember on wich wire you should be connected. I have sold all the official workshop documentation with the car...
The potentiometer is movable on its base to find the correct position, so correct voltage, if not this means it is worn.

Sorry for not giving more precise info, I did this job several years ago...

 

I believe in efficiency and performance delivered by the machine. If we are not not getting the appropriate r.p.m. at particular acceleration then we can say that efficiency is not properly maintained.

 

I have to disagree with you Steve. Efficiency is not determined by RPM vs accelleration. As RPM is a measurement of engine speed and accelleration is a timed measurement of how quickly a speed is reached. Efficiency is also not always the road to power.
Performance, I believe, is using the power band range of an engine with the use of appropriate gearing within an acceptable use of fuel consumption.

 

I agree with you.
To enhance a little bit gearing, i Have replaced the original waccum modulator by one that you can tune to change the level of gearing; The difference is noticable, the gears seems to be shorter because you are more on high RPM. Never the less you can cruise as usual...

The ECU modified By AJ6 enhance also the response of accelerating (not the power); there is parallely a second electronic circuit witch is more "sport" and it depends how you manage the accelerator, it switch from origninal to modified and acceleration is instantly. (sorry for my poor vocabulary)

Consumption was the black point...because bigger butterflies and big cold air intake (80mm)

 

here is mine , YES its loud, and yes it is annoying at constant cruising!

but around town and just having fun its Kool.

pic of side exhaust with 5" outlet, bit over the top!

engine looks good , won trophys for engine appearence.

dyno runs,with closed hood(bonnet), and open hood without filters,and overhead fans blowing down into engine bay, made 3hp difference.. !!??


now if i only knew how to video the sound,i would!