sound of the v12

[morganjag]

Are there various designs of exhaust systems for the v12 which are varying decibels ? My v12 has a very sophisticated sound which I'm gradually getting used to but it would be nice to have a slightly more sounding exhaust note as she is so smooth , ok I'm used to v8's I'm afraid !

[PeterCrespin]

AJ6 Engineering do a stainless extractor system in two versions: modest and 'Supersports' loud

[42south]

Hi
Lots of guys have modded their exhaust system to achieve a more sports car sound.
Try a search in this forum for v12 exhaust sound. In particular read what Woolfi, a German contributor, has to say.
Ive done mine in similar fashion but with no rear resonators, the sound is great.

[Barry]

I have the "modest," AJ6 Engineering exhaust on my 6.0 litre fuel injected car, and it sounds fantastic. No need to go to the Super Sports version unless you really want to drown out any form of conversation! I am sure Ecosse would make you a system as well. Depends whether you want the fishtails. The AJ6 system has to straight exit pipes with resonators.

[Woolfi]

I have done a big 45 mm hole longline in the entrance pipe. Now my silencers are similar to a straight-through silencer. The sound is still like the typical EV12 sound, but a little bit more aggressive and louder.
My car has also no rear silencer. The sound is much different and louder. Therefore I think, that you should stay with the back silencer.

The big problem is, that the mixture is weakening, if the back pressure of the exhaust is reduced. The power will reduce a little bit. The cahnce of piston burning when driving hard is rising. To avoid this, the motor needs four new "tailor-made" needles in the carbs. How to do this, is clearly described in the book of Des Hamill about the SU-Carbs. This work must be done for every sports-E-typeI with more power. It is a lot of work and testing the exhaust gases with a lamda-gauge, until you have the new needle with a shape, that "produces" ther correct micture in all driving situations.

If you start to make a smaller hole (lets say 15 mm diameter) inside the silencers, maybe the sound will become more "sporty" and the need for another needle is less important.

If you do the complete work with the 45 mm hole plus the correct needle, the motor will provide a little bit more power. Maybe 10 hp.

I know a guy in Germany , which is selling for roundabout 350 pound four "hand-tailored" needles for this situation. His EV12 is sounding great and running strong.

Regards Wolfgang Gatza

[JJC]

Try this...I have run it this way for years, with pleasant results. Remove rear silencer (under trunk), store it as far back in your garage as possible, so you wont be tempted to put the dumb, rust prone, ugly thing, back on the car. Now simply drive to your nearest muffler shop, and have them build you a set of straight pipes (with a slight bend upward of course, to follow contour of the car) , long enough to reach past you licence plate. This will insure no nasty exhaust gets into the cabin. Next, search the internet for a lovely set of chrome exhaust trim, and have shop weld them on. It will look and sound great. Just a wee bit louder, and an absolutely lovely exhaust note. All in, I doubt if you will spend more then $200 US. Enjoy !

[Woolfi]

Hi, Lots of guys have modded their exhaust system to achieve a more sports car sound.
Try a search in this forum for v12 exhaust sound. In particular read what Woolfi, a German contributor, has to say. Ive done mine in similar fashion but with no rear resonators, the sound is great. Marc Brown
Marc has his system modified like I have done mine.
1. stage: you can make two holes of 20 mm inside the 2 front silencers. We took a long 20 mm thick round iron and hammered it with a big 10 pound hammer through a inner iron of the mufflers. If you do the 20 mm hole on the side of the 48 mm pipe and you think it is too less, you can make another 20 mm whole on the other side of the iron inside the pipe. Like stage 2.
2. stage: you can widen the hole up to 48 mm.
3. stage: 1+ 2 plus you can mount two 52 mm pipes instaed of the rear muffler.
4. stage: 1 + 2 + 3 plus cut a longline hole from the outlet of the two mufflers into the "holepipe" ( a pice of pipe with hundrets of holes) of the absorption silencer part of the two front mufflers. Open the cut with a big screwdriver und fiddle the steel-wool out with a long thin hook. The absorption part of the two front silencers will loose his ability to extract / damp the high frequencies. The sound will become more "toxic" / sharper.
If you do like this and you fiddle with different solutions, you can find your personal taylor made sound.
Stage 3 sounds great like Marc wrote, stage 4 is really loud, if you press the pedal.

I think stage 1 or 2 are the best "quick and dirty" solution. Easy to do and CHEAP. The sound is like original, a little bit louder and "sharper". This is the real EV12 sports sound. If you think it is to less "sporty" you can add stage 3 and take away the back muffler.

The car in the video is stage 3 with less "steel-wool" in the two silencers. The pipe diameter of this self-made system is 55 mm, roundabout 5 mm more in diameter. The inlet holes of the back muffler are also roundabour 5 mm wider. In original they have only 43 mm inner diameter, therefore a restriction.

Regards Wolfgang Gatza

[42south]

Hi guys
Here's a pic of a 52mm straight through exhaust. You will notice I have done the Marek mod on the rear tailights, nice to get rid of the messy reversing lights.
We did have to flatten the pipes where they go under the IRS to keep ground clearance.

[Barry]

Noise is one thing in this debate, but actually getting the right sound, and with more torque and power is the key to real success. I'm not sure the home made mods will give the power and torque increase. I am no expert, but it seems the correct thing to do is buy a ready made system from the experts. The development and knowledge is vital to get the correct results. They aren't expensive when you consider the value of our cars. Classicfabs have just announced a full V12 exhaust complete with a new extractor manifold. Heywood and Scott also have a system. Roger Bywater at AJ6 engineering, has two systems as I explained earlier in this topic. I'm about to upgrade my TT system from Roger to a Super Sport with 4 rear outlet pipes, but to keep the noise within tolerable limits, I'm fitting his two small central silencers. Bear in mind Roger was a development engineer at Jaguar when the V12 was being designed, and is acknowledged as the most knowledgable guy on V12 Jaguar engines.

[Woolfi]

"'m not sure the home made mods will give the power and torque increase. I am no expert, but it seems the correct thing to do is buy a ready made system from the experts."
I have done the modification and measured the back-pressure with a gauge at the thick iron 3in1 collector at nearby the cylinder hat. The pressure at 5500 rpm at full throttle was 0,15 bar. This is neaby the value of 0,05 bar of a very good sport exhaust system.
A friend of me has a Supersport system from AJ6. This was much too loud and he was forced to mount two small extra absorption silencers in the two pipes in the mid of the car. His car has NOT the plus 12 - 14% of torque in the midrange compared to my car, which AJ6 describes. Aj6 also don't show results of a dyno run compared to the original system of the EV12.
If the TT-pipes of AJ6 produce up to 14% more torque in the midrange compared to the original system, maybe because the original system has more back pressure than the system from AJ6.
The solution I described in my post before, has the big advantage, that the cost are very low and the owner can compose the sound like he wants.
Another friend of me has checked a sports system for the EV12 from a big supplier very carefully. At a certain point, the diameter was less than the original system. How shall this sport system has a lower back pressure than the original system ? How shall it produce more hp ?
I know very well, that a good design of a silencer system is more than low back pressure. But if you lower the back pressure of the original system with the big 48 mm hole in the entrance of the front silencer, you can have with a small amount of work and nearly no cost a silencer system, which adds (few) hp to the motor. I don't believe, the all the polished stainless steel silener systems, which you can buy, offer more hp.
I have measured ALL of this with a pressure gauge and a lambda wide band system very exactly. I realised, that the mixture weakened, after my system had lower back pressure. Therefore I MUST (!!!) reshape the needles , that the mixture was okay with the "new" silencers.
I NEVER have red in the internet, that any of the companies or "specialists" , which are producing sports systems for the EV12, offer 4 new different needles. NEVER ! Maybe because they are too much foolish, to understand , that the mixture has to be adjusted. Maybe they hope, that most customers are fools, that the don't realise, that there is no advantage in power.
Maybe on roads in the UK you can't feel the small lack of power, if the mixture is too weak. If you drive on a german Autobahn with 70 miles and press the pedal, your eyes will become very big, if you watch the weakening of the mixture on a lambda wide band gauge when the motor is reving above 4500 rpm. At wot the mixture is becomming weaker and weaker , when the revs are rising. Also I have felt the reduced torque after I have drilled the 48mm holes in my front silencer. The car accelerates softer, than with the original system. But the ass is a bad "dyno". A correct mounted programmed lambda wide band shows very clear the need of needle "reshaping".
Robert Bywater knows very very much about this motor. He offers sports exhaust systems for the EV12. For the injected cars he is offering reprogrammed computers, to "repair" the weakening of the mixture. I am wondering, why he was writing, that you don't need a change of the needles for the carbed motor of the EV12, if you mount one of his sport exhaust-systems. He is writing, that the Carbs would readjust the mixture automatically. He knows much more about the motor of the V12 than I. Therefore I am a little bit suspicious about my opinion, that the needles have to be reshaped. But I have MEASURED the weakening of my mixcture exactly after I have done the silencer work and have been able to cure this with "reshaped" needles. Exatly same with a friends car, which is shown in the video of my last post. For most of the sport silencers, which are offered for motobikes, the dealers offer also reshaped needles, if the motor has carbs.
In the book of Des Hamill about SU carbs, the work of reshaping carb-needles is explained very exactly.
Without this and some minutes full throttle, you risk burned pistons.
Regards Wolfgang Gatza

Read also: https://www.quora.com/Does-exhaust-chan ... f-the-bike
I think you can find also a lot of other posts in the internet, which explain the need for other jets or needles in a carbed motor, after lowring the back pressure in a motor.

[Woolfi]

I think if you are doing stage one, (20 mm hole) plus stage 4 (extracting the steel wool out of the second camber of the two front mufflers), there will be no or low need for reshaping the needles.
This is a easy way to a more sporty sound at the EV12. The biggest problem is to take down the silencers, because of rust in the pipe connections.
Regards Wolfgang Gatza

[42south]

Hi guys
here is a link to the sound of my car with straight through glasspack underbody mufflers, the same size as the originals, exiting into 52mm pipe with no rear resonators. This is stage 3 of Woolfi's ideas.
Sounds great to all my mates, translate=(Friends), even my missus, translate = wife, loves the sound. Its not too loud at 100km/hr, much better than the radio.
You'll notice that I have disabled the Stromberg bypass valve, hence the exhaust popping on the overrun, I love that sound as well.

[Barry]

I have been doing some further research following Classicfabs announcement that they are going to make tubular V12 manifolds. Hayward and Scott also make them, and I gather from Chris at KWE that on the dyno it make 50bhp difference but lots of extra torque all the way from 2000rpm. Bell exhaust do something similar, but their quality is a little suspect, but you get what you pay for. The coments about drop in torque with the AJ6 system is clearly rubbish. Dyno tests show an increase in torque across the range, and approx 25bhp at the top end. Roger Bywater got a well known and reputable Yorkshire based exhaust manufacturer to do the research and make his systems in line with his concepts and theories. However, Roger will not really do any verification on additional power outputs for his products! Others do having bought from him!

[42south]

Hi
Why doesn't someone publish the Dyno results, to prove the power increase?
In fact I can't understand why Mr Bywater hasn't done it to end the aspersions cast by some about his systems.

[MarekH]

Anything which affects the engine's breathing, in or out, ought to want to be reflected in a different amount of fuelling and a different amount "bang" in the cylinders means a different amount of torque and power.

Mr B sells his ECUs and throttle bodies to reflect this, so I suspect he isn't too keen on wanting to strip down the causes, the effects or assign a percentage to each component since it may show that most of it doesn't do a lot for you in isolation when bolted onto an old customer engine.

By contrast, replacing an unmaintained semi-life expired set of components with a whole kit of something new will inevitably prove to be a big success, i.e. you have to spot the benchmark as to what you want to compare to. Simply maintaining your car properly will give a huge performance increase compared to the average non-customer's car but you can't make any money out of that if your business is to sell go faster bits.

He is absolutely right to point out that having more torque in the overtaking rev range is a more useful goal than having a piece of graph paper with a steeper line on it and in that respect, needing to "prove it" at 5000rpm is a bit of waste of time.

kind regards
Marek

[Woolfi]

"I have been doing some further research following Classicfabs announcement that they are going to make tubular V12 manifolds. Hayward and Scott also make them, and I gather from Chris at KWE that on the dyno it make 50bhp difference but lots of extra torque all the way from 2000rpm. Bell exhaust do something similar, but their quality is a little suspect, but you get what you pay for. The coments about drop in torque with the AJ6 system is clearly rubbish."
This is ALL clearly rubbish !
1. I have tested the difference between a EV12 with tubular manifolds and a EV12 with stock front manifolds + openend silencers + no rear silencer on a german Autobahn.
Two different cars, two different motors but nearly the same acceleration from 50 to 120 mph. I could NOT see any power gain for the car with tubular manifolds.
2. I am not shure, but I think I have red in the internet, that the tubular manifolds for the EV12 are much to short, to produce more power.
I have red in a car magazine, that Alpina, a big german tuner for BMW cars, uses the original cast manifolds of the old BMW 2002 for motors up to 100 PS/L. This is much more than the 55 PS/L of the EV12. Only for motors with more than 200 Ps (motor has 2 l of displacement) they mount tubular manifolds.
3. I have measure in REALITY, that the mixture of my own EV12 with 5,3 l motor has become lean, after I have oppenend the 2 front silencers of my EV12.
David Vizard has also written about this in his big tuning-book. If a exhaust system has less back pressure than the original system, the mixture will become leaner.
I am not shure, that a V12 motors is running leaner, when the tt-pipes from AJ6 are mounted. But I have doubt, that the mixture will be the same, after the exhaust system has been changed to tt-pipes.
I am shure the the mixture will be leaner, if the supersport exhaust system from AJ6 for the EV12 has less back pressure than the original system.
I and a friend with another EV12 have measured that the mixture has become leaner, after we have openend the original EV12 system to less back pressure, We both cured this, by mounting thinner "taylor made needles".
Regards Wolfgang Gatza

[Barry]

Sorry my friend, but the dyno never lies! I asked for clarification, and they confirmed an increase of 46bhp for the manifolds. Now, you may be right about mixture, but my V12 has a factory 6.0 litre engine with fuel injection, AJ6 throttle bodies, AJ6 Torque Plus kit and the said Sports exhaust. So I am not concerned about that as mine is sorted by an ECU! I am delighted you have done some home made mods and got some real improvements but dont knock the respected professionals who really know and understand what they are doing!

[42south]

Hi Barry,
where was the HP increase?
Some have suggested that it is only at high revs, an area most of us are unlikely to use often.
If it was in the mid range it would be an advantage. I certainly would like more in this area for overtaking.
Cheers
Mark

[MarekH]

Dear Barry,

The dyno may not lie, but it didn't tell you which component provided the extra horsepower unless you dyno'd it between every component change.

You may find that simply pumping in more fuel changed the graph once one of the induction/exhaust components was changed and that the dyno would have given you lots of different answers in between.

To simply claim it is the manifolds themselves that give the hp increase ignores the fact that a larger throttle body allows more air to go in and thus the engine will want more fuel to go with it. It is a sleight of hand because you are really just looking at a different point on the engine map in much the same way as a carburettor naturally adjusts for airflow.

Given that the horsepower graph is monotonically increasing, you can always just have more by opening the throttle more until you reach the last quarter of the graph, when the breathing may beca=ome the limiting factor.

All that the induction manifolds do for you is try to equalise the airflow between cylinders and slightly increase the runner length to move the peak torque band lower down the rev range. They probably do contribute something to the efficient breathing of the intake by virtue of tidying up the airflow by using trumpets, but no one has done any A-B comparisons as to where the "benefit" ought to be apportioned to.

I'm not saying it isn't a positive thing to do, but I am sceptical about people's understanding and description of what is really going on.

kind regards
Marek

[chrisfell]

Having an extra 50 bhp at 5,250 rpm (or whatever) doesn't mean that 50 bhp is there at every throttle angle.

If I want an extra 50 bhp to overtake, I just press the throttle a little harder. The performance gain of this manifold over that is only really usefull when the car is driven at WOT all the time that grip is available, and if you are doing that I hope the roads are clear when you are driving.

Or you are on a race track.

In the real world, where the rest of us live, our E-Types could benefit from an efficient system of silencers that allows us to bimble quietly along a leafy lane, never exceeding the posted or national speed limits, whilst sipping as little of the go-go juice as possible, whilst at the same time allowing the full use of as much torque as is required to accelerate when the circumstances demand. If that efficient system comes with a pleasingly sonorous burble, and a little bark when progress is required to overtake, so much the better.

Which was, perhaps, the intention of the original poster.