S1 4.2 Exhaust Questions

[Toblerone]

Dear all,

As I am coming to the end of the restoration of my S1 4.2 OTS I need to decide on an exhaust system. The factors I am considering are:
- The engine is standard.
- I want to be able to drive distances without the noise level becoming tiring.
- I prefer the look of the standard manifolds to stainless but only while the ceramic lasts and I understand that this will not be for long. Consequently I am leaning towards a stainless manifold and I am quite happy with the blueing over time.
- Lead time needs to be 4-5 weeks (I have left this a little later for some of the manufacturers unfortunately).

Having read all the exhaust related threads I can find on the forum I have the following questions that I would appreciate people?s thoughts on:
- Is there an effective paint that can be applied to the standard manifolds once the ceramic coating deteriorates?
- SNG B supply a bell system (complete with manifold) in standard, sports and big bore. Is the sports system still comfortable on the ears for long distances with the roof both up and down? Are the sports or big bore version likely to cause the low/mid rev torque dip?
- I have looked at the Classicfabs systems which look fantastic but as they only do them in 2? I am worried about the low/mid rev torque dip on a standard engine. Does anybody have any experience of this.
- What other systems/manufacturers would people recommend?

Thanks in advance for any assistance.

Clive

[Heuer]

1. The standard Jaguar manifolds produce the best through the range power output from the XK engine. Tubular manifolds cause a torque dip between 2,250 and 2,750rpm
2. Tubular manifolds increase under bonnet temperatures to a point they will bubble the paint on the the frames
3. Tubular manifolds increase noise significantly and you can hear ignition pulses at low revs which can be really irritating
4. Tubular manifolds change colour with use - shiny > straw >blue > dark brown rusty colour which looks horrible. You can not polish any of it out
5. A big bore exhaust system will produce more power at 5,500+ rpm but reduce low down torque. Stick to 1.75" bore.
6. A straight through silencer system will increase power by 6% with a consequent increase in noise
7. A big bore system produces more low frequency noise. This sounds fantastic at 3,500+rpm but can be wearisome to driver, passenger and other road users below this
8. The vitreous enamel coating on the Jaguar manifolds is long lived provided it is not exposed to water when hot. Unfortunately if it is raining and you apply the brakes water rushes forwards off the screen and bonnet down the louvers and onto the front manifold which causes the finish to immediately crack. I have a set of manifolds which have covered many thousands of miles of high performance driving - the finish on the front manifold has all but disappeared, the rear manifold is like new.
9. I have yet to find a manifold finish that will resist the effect of heat and water. This includes the various ceramic finishes on offer. Best and cheapest option is BBQ paint. It is matt black and can be reapplied as many times as you need to.
10. For road use the very best combination is Jaguar manifolds, mild steel 1.75" exhaust system with baffled silencers and chromed resonators. This is how E-Type's used to sound back in the day and is what I have on my FHC. Each change from that spec will introduce compromises. On my OTS I am now using Jaguar manifolds, 1.75" stainless steel exhaust system with straight through silencers. This allows quiet progress in traffic or long distance runs but a beautiful noise once the revs get past 3,500rpm

[Toblerone]

Heur,

Thanks for the quick reply. I would be very happy with a mild steel exhaust and chromed resonators. Do you know of anybody that can supply these in a reasonable time frame?

Regards

Clive

[Heuer]

I bought my mild steel system from PD Gough (aka Nouvalari) in Nottingham. They have the original patterns. Turnaround time was about three days for cash, longer otherwise. http://www.nouvalari.com/contact_us.php

Bear in mind the resonators will be mild steel so will require chroming which bumps up the total price. They will make the system out of stainless steel with polished resonators if you want (which is what I have on my OTS but with straight through silencers). Basically you can have anything you want as the systems are made to order.

[christopher storey]

Just to add one small point to David's very full summary - something about the SS manifolds that I particularly dislike ( along with the tinkling combustion noise ) is that on a lengthy uphill stretch - more common in Europe than here in UK - you can smell the SS getting very hot

Incidentally, I understand that PD Gough are also very well thought of in Rover V8 circles for making any system you care to specify to very high standards

[Heuer]

Ditto in Ferrari, Maserati and Alfa circles.

[Toblerone]

As I will mostly be driving the car up and down hills in the Alps the smell going up hills is definitely worth considering.

I have requested a quote from PD Gough through their website. Are they able to get the chrome work done or would I need to get this done separately.

David, is there a big difference in volume between your system with baffled silencers and straight through silencers? I have a 5 speed box so noise above 3500rpm might be more of a joy on mountain climbs than a chore on long distance runs.

Regards

Clive

[Heuer]

Chroming needs to be done elsewhere. I used Nottingham Platers as they were on the way to PD Gough. So figure ?600 for the exhaust system and ?250 for the chroming. They can sell you a s/s system with polished resonators for ?700 or so.

Baffled are fairly quiet as you would expect from Jaguar. I quite like the straight through silencers (the resonators are already straight through as standard) as it gives you the best mix of quiet touring with the option of hooliganism (and extra power) thrown in. My OTS has a 5 speed box and 2.88 diff so 3,000rpm = 100mph which is great for relaxed touring. Drop it down a couple of gears and you are into 3,500rpm+ territory which makes those Alpine hills come alive with the sound of music!

[Toblerone]

David,

I have spoken to PD Gough and they are suggesting doing the resonators in stainless steel. My assumption, however, would be that the resonators are quite integral to the sound and much of the point of going for a mild steel exhaust would be lost if they were stainless. Would this be a correct assumption?

Regards
Clive

[trondvo]

I have had a Double S system in my OTS for almost two decades, it is the original spec system and am very happy with it. Have to be hard on the throttle before it makes any noise.

Will be getting a Bell oem spec stainless from SNG for my FHC, many people recommend the system. Decided to use original manifolds. My engine is being "refurbished" to original specs as well.

Agree with David, I rather paint the orignals every two years than running "headers".

Had SSI stainless manifolds (combo w. heat exchangers) in a 911 w RS engine, when hard on the throttle they made lots of heat. Too much for my liking.

[Heuer]

Clive

It most certainly would - the exhaust note comes from the 'resonators' and mild steel sounds very different to stainless steel. I have one of each so have been able to compare and contrast. Either go for a complete stainless system or complete mild steel. The cost of chroming my 3.8 resonators was ?125 each, softened somewhat by the lower cost of the mild steel system. Worth it though for that glorious period sound. I have a mild steel system on my Lotus Elan as well and that sounds equally fantastic. It has been on the car since it came out of restoration in 1995 and shows no sign of rusting through. Why owners of classic cars are wedded to stainless steel is beyond me given they are unlikely to be used over winter, or in many cases, even in the rain. Only precaution you need to take is ensure the exhaust is fully up to operating temperature before putting the car away - less chance of internal condensation.

[Toblerone]

David,

Thanks very much for all your advice. I ordered the full mild steel system from PD Gough and couldn't recommend them highly enough for their service. Extremely helpful and they had the exhaust made and packaged ready to send within days. All the chrome items for the restoration still need to be done so the resonators will get done at the same time. I'll try to remember to post again on my thoughts when I finally have it fitted and have driven the car, which for various reasons won't be for another two months unfortunately.

Regards

Clive

[abowie]

Will be getting a Bell oem spec stainless from SNG for my FHC, many people recommend the system. Decided to use original manifolds. My engine is being "refurbished" to original specs as well.

I fitted another of these systems to a car we are restoring for a friend. S1 4.2 OTS. Took me about 90 minutes. Perfect fit apart from needing to trim about 20mm off the back of both the downpipes.
These are good systems.

[pmansson]

I fell for the s/s trick when I did my father?s old S-type back in 1984. Within a year I dumped it and installed a full mild steel system, which was then still available at reputable exhaust shops. It is still on the car, or did I replace the main silencers a few years ago...Cannot remember.Not that they were rusted apart, but that the engine was out and it was an opportunity to replace. What I did back in 1984 was to drill small holes in the lowest parts of the vertical ends, to allow condensed water to seep out. If you avoid short drives, when neither engine or exhaust system have the time to fully warm up, the system lasts for decades. Much better sound, esp on saloons which should be RR quiet, but allow for a modest roar >3500.
I have the same mild steel on my 420 Gs. I found one NOS main silencer for my Mk 9, which I will use after I find a shop that will make the second one. Perhaps P.J. Gough whose system I have on an E-type.
On another E, there was a terrible resonance around 3.000 i.e. at motorways with a 5-speed box and original US setup 3.54 (a combo I like very much), so I chucked those (s/s main silencers?) out.
As for the exhaust manifolds, CMC has a fairly new supplier whose glossy black surface appears to last in most conditions. I have Zircotek coated manifolds on one car, and it is fine, but looks matte grey rather than glossy black.