Hi all

I have been drooling over what AJ6 Engineering can offer for the 6 litre V12, but as I have the humble 3.2 I am looking also at the TT exhaust - has anyone tried this? It is two long parallel pipes that replace the Cat Convertor and continue the separate pipes from the 2 manifolds back to the gearbox. AJ6 state that it improves mid-range torque and performance, which would suit me for everyday drivability.

Also, I wondered how good a pod filter can be over a clean, new standard paper filter.
I am tempted to cut a big hole in the base of the standard filter box , instead of a pod

Pod-wise, I thought this one in the US of A looked nice... Jaguar XJ6 XJR Performance Intake K&N system

 

Forget the pod filter as it does not flow any better than a paper filter.

Forget any intake modification that results in introducing heated engine bay air to the intake.

Have you got an Andy bracket yet? That is known to work well.

 

yes, have Andy's bracket, run on 98 octane (dropped 0-100km/h from 10 to 9.5 secs), then multiple syn ATF changes have lowered it further to 8.7-9 secs

I cut a rectangle hole in the lower surface of the filter box lid today, on the outer side (the 'in pipe' leads to the inner side). It may or may not help breathing. I will find out over the next week or so.
I am tempted to get a local exhaust place to 'copy' the twin pipe set-up.

I see the stock exhaust has two tapered expansion-type chambers immediately below the manifolds, before converging as one - this is not present on the TT system. Puzzled..

 

Don't waste your time on a twin pipe
Jaguar went to a single pipe then splitting into a twin for a reason off the mark power I.E. bottom end midrange is nice if your going through the mountains but daily driving stop start you want bottom end plain and simple
If you wanted to get some more power reasonably remove the underfloor cats and middle mufflers and replace them with a single in twin out resonator
I spent over 10 grand designing and building my headers and system and was not exactly happy with the results the guy that built the system is a ex jaguar racing guy and built the system for the jaguar V12 that won Bathurst years ago so knew his stuff

As you can see in my system I don't have cats at the front don't want to interrupt the tuned length of the headers
I went with metal substrate cats under the floor but after doing my system I had to add another resonator in front and new rear mufflers to shut it up and stop the drone it sounds awesome now but I did learn a bit along the way
The underfloor cats are a bad design to meet emissions in some country's

 

That's one clean undercarriage.

What size pipe are you running?

 

thanks Doc
my understanding of the AJ6 Engineering twin pipe TT system was that it cut out the cat, and extended the separation of the 2 exhaustmanifolds further back for better torque - "Extractor Torque Boosting (TT) - uses dual tuned length pipes from the original manifolds merging in the vicinity of the transmission then running through to join up with a standard or l arge bore rear section. These systems augment flow through the engine thereby significantly improving mid-range performance."

So would that fit with what you are saying you did?
cheers

 

The headers are 2 section's of 3 each
primary pipes are 1, 3/4 inch going into 2,1/2 inch then into 3 inch splitting into a twin 2, 1/2 inch
this set-up is overkill

If I was doing it again using 2 sections of 3 using 1,5/8 primary's into twin 2,1/4 into single 3 inch then to 2,1/4 tail pipes

I would also instead of twin cats and twin resonators use a single 3 inch in and out cat and a 3 inch in twin 2,1/4 out resonator pretty big cost saving using 1 cat and one resonator and with the pipes being slightly smaller diameter

I wouldn't have needed the resonator in front either again a fair cost saving

I had to add the front resonator to shut it up and redesign the rear mufflers again to shut it up and stop the drone

The first weeks of the system before the Mods to shut it up the car sounded amazing should have heard it on the dyno oh my god

But the xjr is a street car and gets used daily around town and highway use and I am also a bit older now LOL

I still get other jaguar owners give me second looks or try catch up to me in traffic

As I am probably one of the few guys in the world with a full system on an XJR6 I did a few years of research before attempting it

So when I pass on ideas its from personal experience

It all stemmed from cracked headers

Bellow are the direct replacement 304 stainless headers I make and sell for the AJ 16 engine I wish these had been available when I started the process would have been so much easier and cheaper

 

But it wouldn't be near as purty!

 

The TT system would work beautifully if you didn't have front cats the front cats mess up the whole tuned length aspect

If you have to have cats I am not sure in NZ but here in Aus they are supercritical that's why I put them under the floor the ones I used are metal metal substrate which heat up quicker than the old style cats so no need for air pump

Its all about cost a decent shop could remove the front cats make a decent flowing 2 into one section make that single section 3 inch then where the underfloor cats and resonators are fit a single 3 inch metal substrate cat and a single 3 inch in twin out resonator that would be legal reasonably priced and make power and have no drone
the rear mufflers on a N/A car are twin pass
on XJR cars they are triple pass

I can get the 200 cell metal substrate cats from the manufacturer he is in Brisbane they stopped selling them but last time I was there he had quite a few left over and did me a really good deal
again its all about the money

Again this is what I would do to a 4.0 S/C engine

Yours being the smaller engine the primary out of the stock headers would be fine with a 2.5 inch single pipe and 2.5 inch in and out cat and as long as possible straight through resonator with a pipe behind the resonator splitting into the original twin system A good shop could do that pretty easy

The bigger the pipe diameter the greater the chance of droning and that makes a good car horrible

The thinking behind large diameter single front pipe is get the gases out

The front section of the headers make power the rest is to shut it up that's why you see racing cars run just headers and nothing else in the real world that's not possible if you want to keep your neighbours on side LOL

 

i can get away with no cat as far as I know (should probably check...)
I was thinking something simple - 2 parallel pipes bolted to the two exhaust manifolds, no cat, the twin pipes becoming one by the gearbox just before they split apart again to go to rear mufflers etc

 

Doc: every time I see your gorgeous set up I whimper at the $1K I spent on replacement factory headers that I know will crack.........beautiful job!

 

Al NZ if you don't have to have cats get rid of them at the front and make it a dedicated twin system

My old 91 4.0 XJ40 had a dedicated twin system
The pipes where made of quality stainless steel something they cut corners on the X300 range

The original exhaust system on my XJR looked like a Ford parts bin raid

With my old XJ40 AJ6 4.0 engine I changed the air box replaced a lot of sensors and bought a set of pipes from AJ6 Engineering they replaced the middle XJ40 mufflers they said the muffler replacement pipes would give 10 HP my Butt dyno reckoned that was close also got better mileage

No matter what I do to my XJR it gets horrible mileage for a 6 cylinder car
But I'm keeping her forever LOL

 

Doc, thanks. What do you mean 'my butt' - did you not get 10 bhp?
I am not too worried about mpg or bhp, but do want better mid-range torque which is what AJ6 say it delivers.. was that your experience?
cheers

i cut a crude rectangular hole on the lid of the airbox in the weekend, on the outer side (the intake pipe runs across to the inner side) and it seems to suck more air. Also gives a bit more of noise, but not unpleasantly so!

 

I actually have a pod filter on my XJR with a heat shield

I did have an oiled type on first that was a no no the oil killed the air flow meter

I use a dry type in my Jeep I have a KN panel filter oiled but the Jeep uses a different type of air flow measurement so the oil wont damage it

As for Butt dyno I mean seat of the pants and it felt like it gave 10 HP very impressed the guy that bought my old XJ40 was suitably impressed as well

He had been looking for a newer Jag as he wanted to update from his series 3

He had looked at over 40 XJ40,s most said nothing to spend

He got to my house and I just said I have to take my wife to work you may as well come for the run he bought it on the spot said it sounded awesome drove and started better than any of the others he had driven seen or looked at
We have become good friends he still emails me with photos and stories that's the real reason I love jags its the people we are all enthusiasts of some sort just look at some of the guys that post

 

I bought a K&N pod filter yesterday for the hell of it. I wanted to see what difference it would make, not expecting much at all.
I had already cut an oblong hole in my filter box to let more air in the front of it, which gave some induction noise (which I like - not too noisy on the 'little' 3.2).
The pod gives a slightly nicer noise at full throttle, and a noticable improvement in power at full throttle, although I mainly noticed this last night when it was cold (about 5'C). However there was a definite difference.

Doc, now you've got me worried about oiled filters! Although there isn't much oil on this K&N..

 

[QUOTE=AL NZ;781699]I bought a K&N pod filter yesterday for the hell of it. I wanted to see what difference it would make, not expecting much at all.
I had already cut an oblong hole in my filter box to let more air in the front of it, which gave some induction noise (which I like - not too noisy on the 'little' 3.2).
The pod gives a slightly nicer noise at full throttle, and a noticable improvement in power at full throttle, although I mainly noticed this last night when it was cold (about 5'C). However there was a definite difference.

Doc, now you've got me worried about oiled filters! Although there isn't much oil on this K&N..[/QUOTE
I think I might have been exuberant when applying the oil to the filter I did go through 2 air flow meters though