Right, done it and about time too!
New sports cats fitted into the old OE cat cases and the forward of the two resonator boxes complete with unseen H-pipe removed and now on the scrap piles at Longlife Exhausts at Carshalton near Croydon in Surrey.
I took the XJR to Longlife a couple of weeks ago to discuss what I had in mind and to fix a date and time for the work. Longlife are part of a nationwide exhaust franchise group with the Carshalton Branch being the original design for the business. Dan Mathews or his assistant Ellis are the guys to talk too. Prices are very keen indeed and the workmanship is truly top class.
What made me desire sports cats on my XJR? The answer is simple. These cars need a good bootfull of throttle to get them off the mark. That makes them rather a hard drive around town. The lethargy and lack of initial response is at its most noticeable when attempting to enter a fast moving roundabout. There is a most disconcerting lack of enthusiasm to get a move on in such circumstances. Despite my mods made to the XJR which include a reflash, a small fast pulley, a high flow air filter and various induction mods, I had no option to regard the car as a sloath compared to my old naturally aspirated V8 S-type. The characteristic has also been noted by contributors to other internet forums.
The presence of inertia and difficulty imparting momentum to the situation is not imposible to overcome. It requires de-constricting the induction and exhaust systems by removing physical restrictions within the internal supply and ejection components which together cause massive resistance to airflow by way of parasitic profile drag. Internal initial slow airflow is the prime reason causing sluggish performance within the charge air system on any power unit and the more that can be done to clear obstructions, the better an engine can be made to perform across a wide range of operating conditions.
Tom Lenthall has often told me that the standard exhaust 600 cell cats are one of the biggest culprits which will rob an engine of power and indeed economy. 600 cell cats have a 55% coverage cross sectional area within an exhaust system outlet pipe. Fitting 200 cell units greatly reduce such "blockages" which will help to produce more power and torque as well as helping with fuel consumption. Less throttle is needed to keep a car moving with a consequential reduction of fuel used. this shot is of the OS cat looking to the rear of the car. The black plastic gearbox filter/sump is seen to the right of this finely re-fitted reworked converter casing.
This shot is of the NS cat looking across the car towards the NSF wheel. Nice workmanship, I think you will agree.
I`ve just collected my car from Longlife Exhausts and although only having covered eight miles back to my parents home, I`ve been able to form an initial view on the work done today. The service given by Dan and Ellis was top class. Swiftly and with style sums it up. Great guys who gave me exactly what I asked for. The removed the cats, opened them up, gutted out the old 600 cell material and refilled with new 200 cell media to R103 compliance standard. The cases were then re-welded. In addition, the forward resonator box complete with H-pipe was cut from the centre exhaust section and replaced with a purpose built X-pipe to help promote improved cylinder scavenging. This shot looking towards the NS rear wheel shows the new X-pipe fitted in place of the old forward resonator box. It is a very nice job.
The second resonator box was left in place to help control high frequency noise which I considered would spoil this lovely quiet drive of the XJR. The X-pipe has been welded to the second resonator box pipes but this second box could be removed at a later stage if a noisier exhaust were desired. Here we see another view of the X-pipe looing towards the front of the car. The neat TIG welded joint between the new X-pipe and the remains of the old centre section of the exhaust can be seen.
Having driven my old S-type fitted with a resonator-less Miltek cats back system for over nine years, my wish with the XJR was that it remain as quiet as possible. Been there, done that, etc,etc.
The job having been completed, the car was started. Almost as quiet as the old system at idle but sounding rather more hollow and a tad louder when given a rev up. As regards pick up, unloaded, the engine responded in a much faster manner. I coughed up the money and took the car away.
Off the forecourt and onto a slow moving main road, the power delivery was instantly noticeable AND earlier gear changes where instantly noticed...that`s an improvement in lower speed torque delivery. Opportunities to further evaluate the work were difficult due to heavy traffic condtions. Pick up is certainly markedly improved and less throttle pedal work is required. The car just trickles along in a seamless "quicksilver" fashion which I recognize from my time with my old naturally aspirated S-type. It feels very similar as an experience and that makes having the work done worth every penny.
Similar mods to my own can be applied by Longlife to most makes and models of cars which of course includes the Jaguar model range. What I`ve applied to my own car can also be fitted to XK8, earlier XJ models, S-type and XF and XF models in either naturally aspirated or superchargerd form.
It is worth noting that the later cars from around MY05 are blessed with having VVT units fitted to the exhaust cams. The early cars do not have this addition which may explain why there is a slight sluggishness from a standing start. The later cars will enjoy a longer duration valve over lap at slow RPM. This allows improved cylinder scavenging which leads to better power delivery an improved charge air flow at slower speeds. That is good from a driving perspective but the later cars fall currently into a £550 road tax bracket whereas the early cars are taxed at the £290 per year tariff. Some Jaguar models are more equal than others!
Tonight, I`m a very happy bunny. Masterful work from Longlife at a competitive price. Take a look at the Longlife web site and don`t be frightened to have a price haggle. In the meantime, Dan and Elliss get my Five Star rating at the Carshalton, South London outlet. Mention my name if you give them a call. It should open a door for you.
Mike
