This was how the car (3.6L XJS) arrived. 1007mb (high) 16C good. It was so so bad, we took another shot at it to get the scale right. On top of it the driveability was hopeless with a bad dead spot on the throttle making it absolutely horrible to drive round town. The AJ6 toilet ECU was supposed to correct precisely this problem which it manifestly fails to do. The moral of the tale! You can always pay money to go slower, and because it's noiser it feels faster! Then blag in front of your mates because you got more money than sense. It's a big hit on the cred stakes if someone then comes along to show you, you just got RIPPED off, so rather than eat humble pie, you have to start slagging us off.....it's easier. Pity cos rolling roads don't lie, & I didn't take any money to do this test, unlike Mr Bywater. |
It was still not looking funny but showing about 195Bhp from an engine which is supposed to give 221. Owner was depressive after shelling out successively for ECU, buying performance air filter, and going to his local Jaguar dealer who only made things worse! Of course if we took the uncorrected rolling road figures, it would all be fine like they do in the UK. This way it's easy to claim fictitious increases of 10 or 20bhp! I just call that bullshit! |
This is when we start to do a little playing around. hmmm! Is it impossible for a Jaguar dealer even to set the ignition advance right after giving them in excess of 200 quid and 4hours work? I measured a small power increase, but as you can see, all is not well below 3000rpm with that typical NASTY Jaguar AJ6 kink. |
Just for fun we advanced the ignition too far, and you can see the clear onset of detonation. NASTY! better not do that too long! Funnily enough with all that AJ6 engineering toilet the car was still pinking at correct advance at low RPM. Does that start to tell you something? On top of that the exhaust was LOUD and very tiring to drive any distance. Basically what in Germany they call a "lemon"! |
This is where we started to tart up the power output. Guess how we did it? We got all the stuff from AJ6 engineering and threw it in the bin. AND Guess what else? We got a 25 bhp POWER INCREASE. I like power increases, so do customers. All this took under 1hour and a mere 70 Euros, for the rolling road. THIS ROLLING ROAD DOESN'T LIE. Our standard engine is now producing what seems to be 225bhp, which seems good enough for a 200 000kms 20 year old engine to me. However I know we can get more and make the car a dream to drive. |
THIS IS NOT LYING EITHER! This was on the way home, but after fitting our next modification, which consists of adding silencers not removing them. Here we actually start getting POWER increases over the original and as you will see, some super driveability improvements... If the stuff we threw away is anything to go by, this car should leave a AJ6 engineering modified V12 car for dead even with a 6.0L engine. |
Can you spot something? Well the scale is different, but with our VERY TRICK exhaust modification we suddenly make a load more torque and the engine breathes better. More power everywhere, and on our test a week later we were saddled with bad weather and 991mb which is LOW. However our test engine was now making 235Bhp, which is kool, and no signs whatever of pinking at 991mb,so you can imagine the rest. MY job is designing exhausts. I get paid for that. Peak power was also 500rpm higher up at 5400rpm. We are starting to remove that horrible dead spot around 3000rpm, and there's no horrible loud crackly exhaust, just GRUNT. Now why are they all using that stuff in the club racing series in the UK? Because someone high up TOLD THEM like sheep....Roger Bywater is a "very respected tuner". ?political correctness,- forget it,- that's just STUPID. Well....if losing 40bhp and making a noisy exhaust is respectable then I will say BEEEUUUHHHH to that too (!), but I sure as eggs is eggs, am not going to pay a couple of grand for the privilege. MAYBE, just maybe....if you fit the rest of his toilet, you might get BACK the power you originally lost...but even that is far from sure. |
Another shining example of what NOT to do. The inlet tract is already miles too long. Shell out another shed load of wedge to get another unproved untested, but certain power DECREASE. Wanna bet me the price of this dumbass performance "improvement"? Don't forget, trumpets are invariably used in inlet tracts to get a velocity increase in a place where you need it,- usually just before a constriction like in the choke tube of a weber carburettor. The primary purpose is to get the carburettor to work properly and atomise fuel. This mod and the ones below do NOTHING. Strangely, because AJ6 Engineering obviously understand nothing whatever about engine preparation, he/they have been insisting for years no power increase will come from working on the head. That's strange it's EXACTLY what we do next, and even stranger, we get another MONSTER power increase, again without touching the bottom end and with absolutely standard cams and valves. |
Yet another totally dumb idea. This is a total waste of time because the cam timing is very short and so are the original cast exhaust manifolds. The exhaust manifolds and associated valves are wrong in this engine. However we always knew the guys on Jaguar exhausts knew Zilch about design, and the latest V8 ones are no exception. Prediluvian, is the word. Now what was Mr Bywater doing at Jaguar all those years ago? I heard something to do with making a project with a lamer alloy engine that produces really poor power (?!) If you understand what's going on, then you can correct it. Obviously the STUPID idea in the head of the guy who did this is;- "DUUHHH", manifold is too short, so let's make it a mile long!! And then let's sell this toilet for a pile of money calling it "PLUS TORQUE". Better call it "PLUS TALK" and "MINUS MONEY" and "MINUS HORSEPOWER"! |
The final chapter showing KK modifications from England Bore out your Air flow meter! Would be more useful to bore out your nostrils in fact. Enables tuners to think clearer. Most of us use handkerchiefs for this, but if you insist in using a
lathe, then the result can hurt a good deal more than just your pocket!
Ohh.. duh you can of course slag us off, and say our work costs too much, (unlikely) and in any case carry on using your thirsty old engine with a semi blown head gasket, and put the extra money you would save in the fuel tank..... Then next time a healthy 3.6L XJS or XJ40 comes up in your mirror, we gently suggest you move over to let us past because it is probably using less fuel than you do, going 30km/h faster. |
Bad porting | Bad inlet manifold | Dreadful mismatches | Horrible inlet ports |
Chain Tensioners? | A little bit of work later | Sorting out the passage | Better ports not too big! |
The timing chain system which tends to get noisy and clattery on this engine. it took years messing about for Jaguar to try to correct this, but never really succeeded. Luckily it never goes wrong even when rev'ed to 8000 rpm + | This is the tricky bit, get that stupid manifold to sit flat on the head, without blowing around the corners. The steel shim gaskets are a pain, and the manifold often cracks or warps. Gaskets we use seem to cure the problem, but they need to be done up real tight | Some people seem to be unconvinced of the validity of our work and whether or not the standard ECU can deliver more power. Well here's a nice lesson in combustion efficiency. Better combustion, same fuel equals more power less waste. |