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Uggg... the bloviating is really too much. Put down the keyboard and go grab a wrench.
Here's my contribution for today. Full 2.25 inch down pipes, smoothed inside too. One side done and on the car and the other side done tomorrow, These are for a Late 6.0 car that has a 6 speed and sees a few track days every year with the Jaguar Club.
Hopefully these will help a late 6.0 breath better above 5000 where it completely falls on it's face
'Why so much trouble with the HE head': power is generally made in the head, and this head was designed for fuel economy. When Jag did the 6L they got the additional torque, but not the HP, in proportion. You get the proportionate HP when you use the flat heads. See the recent book by Allan Scott on TWR's Group A efforts, esp. the later chapter on 'racing improves the breed'- this shows the proof.
Also: the OEM exhaust on the XJS saps most of the HP potential. We all know this is a big restriction. Group A addressed this by using a replacement cast manifold that kept the three cylinders to a downpipe individual, and then going to a carefully tuned pair of twin tubes, dumping to a 3" collector and out. This is very much like the AJ6 TT Extractor setup (except for the cast exhaust manifolds).
It is useful to look at the Group A progress in pulling HP out of this motor. It is useful because Group A required same sized intakes, exhaust, valves, and valve lift. Cam timing was 'free' and so was piston design and CR. The later Group A cars were producing 500 HP under these conditions. But they did so with carefully massaged intake manifolds (in the OEM envelope) and exhausts. They were also running 12.25:1 CR on this flathead, and they were able to do it because they made improvements in the head gaskets and they were using a specialized crown, and a pin height that got the pistons to within 0.040 of the head (and not 0.150 as the stock motors do). This gave much more squish, enabling the higher CR and more octane tolerance (which is how the HE works).
-M
Mike the HE head was not designed for fuel economy. It was designed to meeting coming California Smog laws. H E does not stand for High efficiency.
Since 50% of Jaguars are sold in California loss of the California market would have bankrupted Jaguar.
Rather HE stands for Help Emissions.
the increase in fuel mileage was in part because of all the other changes. Turbo 400 transmission instead of Borg Warner, improved fuel injection, 2.88 final drive instead of 3.08 or 3.31
11.5-1 compression ratio instead of 7.8- 1 ( England and the rest of the world went to 12.5-1 )
Uggg... the bloviating is really too much. Put down the keyboard and go grab a wrench.
Here's my contribution for today. Full 2.25 inch down pipes, smoothed inside too. One side done and on the car and the other side done tomorrow, These are for a Late 6.0 car that has a 6 speed and sees a few track days every year with the Jaguar Club.
Hopefully these will help a late 6.0 breath better above 5000 where it completely falls on it's face
The lack of power above 5000 has less to do with exhaust ( although bigger is better so you’re going in the right direction) and more to do with the camshafts.
Stock lift is only .375. duration is very mild to improve fuel mileage. Both Piper and Kent will regrind your cams. But they no longer sell the billet cams that needed over sized buckets. Here in the states Crower and Isky will do the regrinding. Isky CM 3 is the best all around grind for street and track. They have an XM5 that is better suited for track use.
With regard your comment about keyboards and wrench’s. I built my first V12’s in the early 80’s. For vintage racing. My turbo V12 in the early 90’s. I’ve owned as many as 50 V12’s at one time. Back then They were very cheap or free.
Back then there were no camera phones, while I have a few film pictures I’m not sure how to transfer film onto a phone. But I’ll try.
You really think Columbus took pictures when he arrived here? I know my father was a combat veteran in WW2 because I have his old uniform with medals. But no pictures.
I served 2 tours in Vietnam but only have a picture or two of that time.( That too is film )
Only very recently did I even figure out how to take pictures with a phone. It seems like such an alien idea. No Kodak film or flash bulbs no waiting to develop it and get the prints back.
MG , just excuses!
you may putted around turbos in early 80s? but todays stuff like ball bearing cartridges etc,,and new metals, computor upgrades in impeller ,turbine engineering has completetly changed the ways systems work!
BB shaft has reduced LAG as 30/50% time to come up on boost!
i did my 1st turbo setup in 1979! no pix a Ford Van V8 before Turbo,van loaded and pullin a trailer loaded slowed on the hills badly, after could run up hills no problem
here are a couple pix of some random stuff i did turbo! i built many different types of turbocharged trucks ,cars , and BOATS! had a business in Florida specialized machine shop for 30yrs!
1st post 107 on this thread PIX , engine 1.8L made 10psi boost measured at the (important inlet manifold,), little pisspot would fly down the road!
some pix of my Mazda rotary RX7,1.3L, BIG turbo made 425 WHP ,at 21psi boost! water to air IC , Alcohol injection, ran some hi 10sec. around 125MPH back 2001.
1985 Buick GN , after blowin up two turbo V6 engines, decided to put an LS2 into it, made much more dependable ! Mazda RX7 street car, ran on 104 AV gas! + Alky! Water to air intercooler, stopped detonation instantly, and close look at Alcohol tank below 3" manifold pipe! Isuzu 1.8L remote rear mount braggin rights, old pisspot car showed some cars the way home! boost gage and ALKY injection direct into inlet manifold, Isuzu! OOPS wrong pic?? 4 =T6 BB garrets. this 20 yrs ago! things have come along way since! the old Grand National more novelty ! LS2 , 4L80E trans, got the job done , BUT 1.3L mazda would blow it into the WEEDS! lotsa torque down low, great burnouts, not really a HI RPM engine(stock)! again today they are unlimited! and now todays N/A pride and joy my Jaguar V12! MG it has more internal mods than ever heard of! looks faster than it is, but at shows it WOWs them!
a guy across the street from me, Porsche 928s his business, he just got from GERMANY , a German spec hi performance engine, has race specs, hi compression pistons, special race heads(bigger ports) and race cams,etc.
got it runnin and it sounds GREAT,badass!
he is using MEGASQUIRT ECU, i listened to him for weeks setting it up, musta used a tank or more of fuel!
pix of engine and stuff! PORSCHE 928 German spec ,Megasquirt ECU. cold air inlet and HI flow air filter!
NOW he has to spend some time makin it nice lookin, like a pain job to start!
ALL in TIME!
MG , just excuses!
you may putted around turbos in early 80s? but todays stuff like ball bearing cartridges etc,,and new metals, computor upgrades in impeller ,turbine engineering has completetly changed the ways systems work!
BB shaft has reduced LAG as 30/50% time to come up on boost!
i did my 1st turbo setup in 1979! no pix a Ford Van V8 before Turbo,van loaded and pullin a trailer loaded slowed on the hills badly, after could run up hills no problem
here are a couple pix of some random stuff i did turbo! i built many different types of turbocharged trucks ,cars , and BOATS! had a business in Florida specialized machine shop for 30yrs!
1st post 107 on this thread PIX , engine 1.8L made 10psi boost measured at the (important inlet manifold,), little pisspot would fly down the road!
some pix of my Mazda rotary RX7,1.3L, BIG turbo made 425 WHP ,at 21psi boost! water to air IC , Alcohol injection, ran some hi 10sec. around 125MPH back 2001.
1985 Buick GN , after blowin up two turbo V6 engines, decided to put an LS2 into it, made much more dependable ! Mazda RX7 street car, ran on 104 AV gas! + Alky! Water to air intercooler, stopped detonation instantly, and close look at Alcohol tank below 3" manifold pipe! Isuzu 1.8L remote rear mount braggin rights, old pisspot car showed some cars the way home! boost gage and ALKY injection direct into inlet manifold, Isuzu! OOPS wrong pic?? 4 =T6 BB garrets. this 20 yrs ago! things have come along way since! the old Grand National more novelty ! LS2 , 4L80E trans, got the job done , BUT 1.3L mazda would blow it into the WEEDS! lotsa torque down low, great burnouts, not really a HI RPM engine(stock)! again today they are unlimited! and now todays N/A pride and joy my Jaguar V12! MG it has more internal mods than ever heard of! looks faster than it is, but at shows it WOWs them!
Good for you. Glad to hear you’ve mastered Turbo’s because I sure haven’t. I’m stumbling around putting junk together very much on the cheap.
My only advantage is decades of racing experience but it’s all obsolete stuff.
Keep up the work.
reading on the aj6 website. with 6.5 liters 500hp shouldn't be terrible hard. its 75hp a liter. the heads flow incredibly. six intake ports and if you look down them the lack of restriction at .440 lift is a ton. with the oversized liners and broadspeed style pistons. itll have a quench around the right spot.
not to mention, I go to school for engineering, and in an.ideal cylinder has a flat head and the combustion chamber souly in the piston.
I have an 86 xjsc admittedly post he but it's taken out to 7.4 litre and produces 533hp on the dyno it featured in the april2011 jaguar magazine
WOW over 550 ft lbs torque at 4700 rpm!
and has to rev to over 7000 rpm to make 500 hp?
am i reading the chart correctly,, most graphs in USA torque and HP cross at 5252 rpm!
but either way that a bad *** motor!
any pix on the dyno?
Wow so close. 493 HP. That's a nice dyno curve too. Flat torque with no spikes or bubbles and HP that climbs consistently. This engine would be driver's car with a manual transmission. Is it an HE or flat head? Stock cams?
WOW over 550 ft lbs torque at 4700 rpm!
and has to rev to over 7000 rpm to make 500 hp?
am i reading the chart correctly,, most graphs in USA torque and HP cross at 5252 rpm!
but either way that a bad *** motor!
any pix on the dyno?
This is Newton meters. 550 Nm
The interesting ting is that this is with std throttles,and std injector size.
If you follow the link under the picture you should get to the dyno video
Wow so close. 493 HP. That's a nice dyno curve too. Flat torque with no spikes or bubbles and HP that climbs consistently. This engine would be driver's car with a manual transmission. Is it an HE or flat head? Stock cams?
Mobeck those cams look radical , lot of duration , and a reasonable lift, looks like a perfect finish , and coated!
very NICE, bet they let you know at idle?
graph says they do work well!
you say standard injectors, can i ask what you have for fuel pressures, in PSI?
Ole did I see you post a pic on FB with a trunk full of V12 heads? Are you selling modified heads?
Hi John
Yes I have a Batch of cnc ported heads going on, with new guides and oversized valves. Will be ready just over summer holiday I think.
And options like a special valvespring-retainer-lifter setup to be able to use cams with better profiles.
The heads will fit exixtig std parts, but my new cams require the special setup with different lifters and springs as I have made them with larger basediameter than the standard 29mm. This makes me able to make high lift low duration cams, or anything above that.
I also do cams with the std 29mm basediameter ofcorse, but then we need to go up on duration to make more lift. Some want that and it is ok to, but I want to have the possibility of std duration and 12.5mm lift.
Mobeck those cams look radical , lot of duration , and a reasonable lift, looks like a perfect finish , and coated!
very NICE, bet they let you know at idle?
graph says they do work well!
you say standard injectors, can i ask what you have for fuel pressures, in PSI?
Hi, the idle was not bad actually, a nice purr at 1200, I could let it down to 900 but sounded a bit stressed.
The injectors is actually not standard, but they have standard flow at aprox 209cc/min, it is the type I use on my Bolt on EFI kit. Or used to use, now I have drained Bosch for them and had to change to another one, sligtly larger but same single spray 20degree type.
I run them at 58 psi on this race engine.
I just mention that thee injectors are like standard (flow) as many people do change the injectors and throttle bore as first thing when they want more power. This kind of proves that it is not the way to go. I was not mssing fuel and it was only 0.4psi vacum in manifold @7500rpm.
Ole Mobeck
Last edited by Mobeck Tekniske; 06-26-2021 at 04:05 AM.
03-04-2020, 10:59 PM
