[racing] Nitrous? XK engine?

Hi.

Has anyone tried Nitrous on a 4.2, 3.8 or even 3.4 XK engine?

I know Top Gear did on a later XJS, but has anyone tried a old XK
lump?

I suspect the answer is a resounding no!–
Lusstor
UK - South, United Kingdom
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In reply to a message from Lusstor sent Tue 8 Feb 2011:

No, but I’m very confident that if done properly it would work on
an AJ6/16 engine, as it is a very robust design.–
Andy Stodart - 1995 & 1996 man XJRs and ex-Jaguar engineer
Northampton, United Kingdom, United Kingdom
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1 Like

In reply to a message from Lusstor sent Tue 8 Feb 2011:

It will gain some!
Because the Jaguar is in a higher state of tune than most
engines it won’t make as massive an improvement… plus a tank of
nitrious doesn’t last very long… If you want another 75-100 hp for
a minute go for it, just make sure you add extra fuel in too so it
doesn’t go lean and explode…–
MGuar
Wayzata Minnesota, United States
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In reply to a message from MGuar sent Wed 9 Feb 2011:

Is it really? I just don�t think it is. Not compared to any modern
engine.
So compression is 8 to one or maybe 9 on a E-type, the ali in the
heads isn�t exactly smooth. The valves despite being in a hemi are
small, the stroke is long and lazy. Huge sloppy crank, Its all big
and over engineered� compared to a modern engine

I would say even the engine on a 1990 Fiesta 1.1 is in a higher
state of tune, with its smooth ports, injectors, computer mapped
exhaust and inlets�

So we know nitrous ads good power to modern lumps, so therefore it
must do something to a XK, I suspect it will make it go bang in a
big way!!!

No criticism of the XK engine, I have two! I was just looking at
ways of making my DS420 Hearse go quicker without fitting a Chevy
V8!!!

I�d like to drag race it, but just don�t think the XK engine would
suit this application.–
The original message included these comments:

Because the Jaguar is in a higher state of tune than most
engines it won’t make as massive an improvement… plus a tank of


Lusstor
UK - South, United Kingdom
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In reply to a message from Lusstor sent Fri 11 Feb 2011:

You are comparing engines decades apart. I’m not sure what you want
to do…
Newer will be better suited than older…
If you want to play with Jagaurs keep it Jaguar… stuff a V12 in
it and then turbo it. (use the older flathead (1971-1980) design
for peak power output) The later HE is a lousy design.
Take a pair of turbo’s/intercoolers from junk Volvo’s and a simple
FMU to add the extra fuel required and you’re at 500 hp+or- Buy a
Rusty XJ-S V12 for under $1,000 steal the motor trans and fuel
injection system sell off or junk out the rest…–
MGuar
Wayzata Minnesota, United States
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In reply to a message from Lusstor sent Fri 11 Feb 2011:

One more point… Nitrous actaully slows the flame front so a long
stroke engine like the XK would see more benefit than a short
stroke motor would… You can also use alcohol, either methanol or
ethanol to a good advantage in the long stroke Jag motor. Again
slower flame front. Add a little nitromethane to it and if it’s
rich enough some fantastic power is available from a relativelt
stock motor…
DO NOT MAKE THE CLASSIC MISTAKE OF REVING THE XK MOTOR PAST IT’S
REDLINE, unless you want it to go bang in a big way!
MAKE DARN SURE IT’S RICH ENOUGH AS WELL!
The rule of thumb is the carb has to use 2 times as much ethanol
as it would gasolene.2.125 methanol and 4 times nitromethane.
Power gain is roughly 50-55hp on ethanol,55-60 on methanol and
250+ on nitromethane…–
MGuar
Wayzata Minnesota, United States
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Some years ago in a Jag Monthly magazine or something, there was an article
on a guy in Amercia who was drag racing with an XK engine. Can’t remember if
it was supercharged, it must have been and had nitrous. It was making insane
HP and had prooved to be bullet proof.

Of course I might be getting confused and it might have been the Daimler V8,
which was reported to make 1300hp in drag racing tune with standard rods and
cranks …-----Original Message-----

So we know nitrous ads good power to modern lumps, so therefore it
must do something to a XK, I suspect it will make it go bang in a
big way!!!

I�d like to drag race it, but just don�t think the XK engine would
suit this application.

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In reply to a message from MGuar sent Sat 12 Feb 2011:

Cheers.

I am still doing research, i’ll let you know the outcome!

At the moment though the nirtus kits seem to be �600, whihc
is just noth worth it!!!

As for over-reving, I have the book ‘‘power tuning XK
engines’’ I will keep it well under their 5,500 max… ;-)–
The original message included these comments:

One more point… Nitrous actaully slows the flame front so a long
stroke engine like the XK would see more benefit than a short
stroke motor would… You can also use alcohol, either methanol or
DO NOT MAKE THE CLASSIC MISTAKE OF REVING THE XK MOTOR PAST IT’S
REDLINE, unless you want it to go bang in a big way!


Lusstor
UK - South, United Kingdom
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In reply to a message from Lusstor sent Mon 14 Feb 2011:

OK That’s $960 dollars for the kit plus refills. One bottle won’t
get you through a drag race weekend.I don’t know how big the bottle
you are getting but a typical nitrious kit will make maybe 6 passes
if you time it right… So you’ll either need some back up or be
able to buy it on the track.(massively more expensive)
To get the same acceration you can simply lighten up the car.
A car dedicated to that sort of racing is the cheapest way. If
you can fabricate, a drag car designed to use either the V12 or The
XK motor will get you the best results…
Like cheap and dirty? get a V12 engine, trans, front and rear
suspension.(They all unbolt) Another words a rotted old V12 sedan
(XJ-S or XJ12) Yank off the body. now weld a frame/rollcage
between the front and rear suspension… You’ll have maybe 500
pounds ($800)into the whole thing and stone stock you’ll do near
10 second 1/4 miles…
Pull a couple of junk turbo’s off something like a Volvo and
plumb them up. Add a fuel management unit (about$85 new,50+ pounds)
or fabricate your own…You’ll be blistering fast… Replace the
stock injectors with injectors from the turbo Volvo, use ethanol or
metahnol and watch your times drop! Under 1000 pounds plus some
time scrounging up junkyard stuff and you’ll be amoung the fastest
cars there.–
MGuar
Wayzata Minnesota, United States
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In reply to a message from MGuar sent Mon 14 Feb 2011:

Ok, So I want to drag race a road legal DS420 Hearse. I
also want to drive it as a street custom.

Because it will be funny.

Remember I am in the UK, so things are not quite the same as
the US. I really dont like the V12, too big too thursty,
just not for me.

My inital plans were to.

Weld up the rust and get it running.

Get a MOT

  1. remove some the of the 3 tonne weight. eg plexi glass
    windows, one of the fuel tanks, bearer deck, etc etc.

2)add a tripple carb manifold and sun 3 2 inch SU’s

  1. remove front silencers and add tube manafold.

  2. look in to nitrous.

May have to change the auto to a manual… :wink:

At the moment I am just doing reseach…–
Lusstor
UK - South, United Kingdom
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In reply to a message from Lusstor sent Tue 15 Feb 2011:

OK Thanks for clarifing for me… Face it nobody races Jagaurs
because it’s easy and a hearse, well (grin) that should be
differant!
Fuel is the one area that’s virtually unexplored but if it’s
street vehicle don’t go down that road…
You might try a supercharger…
Wait before you panic! A superchrager adjusted and driven
properly will return the same mileage that a non supercharged
engine does…
Next visit the junk yard… there are a ton of superchargers
available that can be adapted relatively easily. I have and it
cost me less than $100 worth of welding and machine work to adapt…
Yes there is a trick but it’s simple.Plus if you ever do want to
get really serious power just spin it faster and you’ll get more
boost which might translate into more power If it doesn’t blow up
first. I’ll explain it if you are interested…
The one I used is a 250 cu in roots type. You’ll want as large a
one as you can get because the larger it is the slower it turns and
the more reliable it is…Plus and I don’t want to get too complex
here… the less heat gain from compressing which is a very good
thing… Face it, You’re likely to buy from a junkyard So it will
already have plenty of miles on it… Keep it turning slow and it
will add thrills for a long time.–
MGuar
Wayzata Minnesota, United States
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In reply to a message from MGuar sent Tue 15 Feb 2011:

Yeah, top fuel etc, is just not viable. Especially for the
road.

Ah things are so different here in Europe to the US.
Superchargers are very rare on cars. Apart from the Mini
Cooper S there are no real superchargers on cars. Maybe on
some luxury cars� Like the Daimler Super V8 and that�s an
oil bath blower, which is quite rare and expensive.

You may get the odd old whimple or roots blower going for
�2K on Ebay but there is no way there will be any in a scrap
yard� Oh and as for scrap yards� The EU law changed a few
years back meaning that scrap yards can no longer keep cars
on the soil etc, they have to be on hard standing with the
oil etc removed� But as the price of scrap metal is now �200
a tonne for steel most scrap cars are scrapped immediately
these days. I am lucky I managed to get the DS Hearse, it
was so close to be being scrapped. It�s a very different
situation to the good old days when cars were cars stacked up!

However, turbos, there are loads of turbos. Garrett and
Cosworth are still going strong and getting a old turbo is
fairly easy. The problem is these days they are often LPT
rather than HPT� Hmmm never seen triple SU�s turbo�b�

I fully understand what you are saying about a big
supercharger spinning slower, as the Jag engine has such
rolling strength on the pulleys I agree this is the way to go.

This is all a bit pie in the sky at the moment, as I have a
tonne of welding and restoration to do�.

Here is a photo of the beast. Oh and it came with the coffin.

The original message included these comments:

OK Thanks for clarifing for me… Face it nobody races Jagaurs
because it’s easy and a hearse, well (grin) that should be
differant!


Lusstor
UK - South, United Kingdom
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In reply to a message from Lusstor sent Wed 16 Feb 2011:

Don’t look at cars for large superchargers, look at trucks… big
diesel trucks.
Don’t knock low pressure turbo’s. They are cheap and practical…
You don’t need to change the internals with forged pistons, special
head gaskets , head bolts, etc…
However For far less than the price of a set of SU’s you can make
a lot more power…
You can do it with all junk stuff and make some serious, durable
power (likly more than you can safely make on a stock engine with
nitrious… For about the same money…
Plus you don’t need to be a rocket scientist…
I ghetto charged a XJ-S V12 and increased the power from less than
300 to more than 500. Plus make that power all day long… Driving
it normally I get the same gas mileage but I have an extra 200+
horsepower under my toe when I want it…
In your hearse dump in a 4.2 fuel injected engine. Steal the
wiring and computer from the donor car and as long as you aren’t
color blind you can hook everything up…
(Oh, steal the tach too!)
The way to do it affordably is to Buy a rusted out sedan that
won’t pass MOT, to get all the bits. Swap them into your car, Try
to sell any other good bits to offset your costs and then take it
in for scrap. Stuff the old engine in the trunk/backseat along with
any old scrap metal laying around and that should be worth 400
pounds. A couple of small turbo’s from junked cars and your less
than 200hp hearse will make over 400 hp reliably.–
MGuar
Wayzata Minnesota, United States
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In reply to a message from MGuar sent Wed 16 Feb 2011:

Yeah the XJ series 3 injection, with the big valves (1 /7/8
rather than 1 3/4) etc, too expensive, because the racers
want the bigger valve size. Apparently the cams are better
as well.

However I like your turbo idea, Is it as simple as
1)get turbo,
2) run exhaust gasses through it,
3) and fabricate the other end in to the throat of the SU�s?

Are there no electrics?
As I have 8:1 compression this may be a solution.

The average engine size for an engine in the UK is about 1.8
or two litre, I think I could run a turbo from a 2 litre
and maybe that would not stress things too much?

But this goes directly against what you said, eg big turbo /
super charger spinning slower�

Whilst I have a fair knowledge of the XK and have built up a
few, I have never really tried to eek out performance from it!

I also think that every KG I can cut from the kerb weight is
money well spent!!!–
Lusstor
UK - South, United Kingdom
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In reply to a message from Lusstor sent Fri 18 Feb 2011:

you’ll have to do a real lot to your XK to make it go like a chev
crate motor like the ZZ4 350, which is availble for USD 5300 fully
dressed, and something like a ZZ4 would put you in the low 14s or
high 13s hauling your limo down the strip.

However doing something to the XK is a cool idea, especially boost,
just don’t think it’s straightforward. You sound like you can weld
so fabricating the exhaust manifold from steam pipe and weld-els is
not too hard. If you want to make power then intercooling is
almost essential and you want a big core that flows well ahead of
the radiator. You can use exhaust tubing and mandrel bends to make
nice compressor plumbing to fabricated air box bolted to the SUs.
This is where it gets interesting. SUs can be made to work on blow-
thru applications but before even starting you’d need to check that
you can get 150hp of fuel plus a safety margin through each needle
and seat valve in the fuel bowls at 3.5psi fuel pressure - I doubt
you can - you might be OK with triples. Assuming you can - big
assumption - you need something like a boost referenced malpassi
fuel pressure regulator, a fuel return line to the tank, sealed and
boost ref’d fuel bowls, sealed throttle shafts, and a way of
increasing relative pressure drop across the main jet as boost
rises so the carbs go increasingly rich as boost increases. BL
used a restrictor at the mouth of the HIF44 SU in their MG metro
turbo in the 80’s to acheive this. You then need a needle and
spring combo to tune it in, using a wideband o2 meter and access to
a dyno or some good back roads. It’s all totally do-able if you
can do the design, fabrication and tuning - but easy to get lost if
you don’t understand the SU blow through carb theory or struggle
with light fabrication and tuning. www.turbominis.com is a great
resource for blow-thru SUs.

The turbo itself - something like the Garret GT35 fitted the the
Australian falcon XR6 turbo would be perfect. A unit from a 2
litre will be short on compressor flow, and real short on turbine
flow, giving you something that spools like a light swtich and is
dead by 3 grand. Getting oil in and out of the turbo the right way
is important. if you want to leran more, read Maximum Boost by
Corky Bell, and Turbochargers by Hugh MacInnes. My latest Jag
turbo set-up is http://www.jag-lovers.org/snaps/snap_view.php3?
id=1252616989

hope this helps.

Cheers, Andrew Robertson, New Zealand–
Andrew Robertson
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In reply to a message from Lusstor sent Fri 18 Feb 2011:

#1 absolutely forget about running SU’s with a Turbo. They simply
will not work and you can spend a lot of time and money trying
unsuccessfully to get them to work…
Turbo’s really need Fuel injection to work properly so You’re
stuck with a series 3 or you’ll need to supercharge it… You can
modify SU’s to work on a super charger.
Do not try to use one turbo from a small engine car… You need 2
Volvo turbo’s are about the perfect size for low boost trouble free
motoring… I can buy them used from junkyards around here with the
intercooler for $75 each.(about 46 pounds at todays exchange rate)
Hook one up to the front exhaust manifold and one to the rear.
Then all you need to do is hook it up to the air cleaner and go on
top.Find the fuel pressure regulator tap into it with a FMU ($85.
or 52 pounds) and as boost pressure increases the amount of fuel
delivered increases to meet the boost. There might be a little
juggling on a rolling road (we call them chsssis dyno’s) to get
everything spot on but that’s it!
You need to shop more because the series 3 engines are dime a
dozen here in the states… Honest I’ll bet I could find several for
$500 or less including the transmission… On the other hand $500 is
also the going price paid for the earlier flathead V12’s (the later
HE’s aren’t worth hardly anything)… (unless it’s the 6.0 litre)
I don’t know where in the UK you are but I suspect like here
junked cars that fail MOT are far more common in the larger cities
(london) areas than elsewhere… You need to get to know a few guys
at local Jaguar dealers (mechanics) Or repair stations that do MOT
work…–
The original message included these comments:

However I like your turbo idea, Is it as simple as
1)get turbo,
2) run exhaust gasses through it,
3) and fabricate the other end in to the throat of the SU�s?
Are there no electrics?
As I have 8:1 compression this may be a solution.
The average engine size for an engine in the UK is about 1.8
or two litre, I think I could run a turbo from a 2 litre
and maybe that would not stress things too much?


MGuar
Wayzata Minnesota, United States
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In reply to a message from Andrew Robertson sent Fri 18 Feb 2011:

While a Crate motor might make more power the cost of one in the UK
would buy him a very fast car to start with.
You have to think affordable…
A pair of used but in good shape Turbo’s from Volvo’s with their
intercoolers are cheap enough ($75ea.) connect them to the front
and rear exhaust of the series 3 XK motor pump the
compressed/cooled air into the air cleaner Then locate the Fuel
Pressure regulator and connect a FMU to it… ($85 NEW) that will
increase fuel delivered as boost increases…
Trying to make SU’s work in boost conditions has been attempted
unsuccessfully many times…
While SU’s work fine in a draw through situation they absolutely
refuse to work properly under boost…
The Only way to use SU’s getting boost pressure would be in a draw
through arrangement where the super charger is right next to the
head and the SU’s are on the otherside. (think Roots type blower
on it’s side pumping into the intake manifold with the SU’s on the
intake side of the supercharger.
Reading how you are doing it proves the old addage never say
never. I’ll bet I’ve seen 10 guys try unsuccessfully to get SU’s
to work in a blow through application. Some of them were very
clever engineers. However this sounds like a young guy with his
first car not as advanced as you are…
Wish I could post pictures to show you mine…–
The original message included these comments:

assumption - you need something like a boost referenced malpassi
fuel pressure regulator, a fuel return line to the tank, sealed and
boost ref’d fuel bowls, sealed throttle shafts, and a way of
increasing relative pressure drop across the main jet as boost
rises so the carbs go increasingly rich as boost increases. BL
used a restrictor at the mouth of the HIF44 SU in their MG metro
turbo in the 80’s to acheive this. You then need a needle and
spring combo to tune it in, using a wideband o2 meter and access to
a dyno or some good back roads. It’s all totally do-able if you
can do the design, fabrication and tuning - but easy to get lost if
you don’t understand the SU blow through carb theory or struggle


MGuar
Wayzata Minnesota, United States
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In reply to a message from MGuar sent Fri 18 Feb 2011:

Guys, thankyou so much.

I was 25odd when I got my 67 S-type and everyone said '‘you will
never EVER get that running…’'I had no car experience and work in
computers, Im now 33 and its got a rebuilt engine, box, engine bay,
front suspension brakes, rebuilt interier etc…
I hope to take it for its MOT this week. I drove it as a smoker
for 6 or so years and decided enough was enough!

You are right that this is my first attempt at welding, serious
mods and a drag / custom car… So this is a whole new ball game. I
can get a Chevy crate engine here in the uk for �2500 ish… So I am
not sure what I will do!

Anyway, I actually got it running last night, for the fist time in
several years (I have only owned it for 2-3 weeks). Its rough,
needs a service and a carb re-build. but at least I can get it in
and out of the garage!

I need to get the welding sorted, then I can get the MOT and then
start looking at the engine. I will read the books mentioned above,
speak to the mini guys and work out what the best route is, idealy
i want 500 BHP, but I think thats dreaming.

I suspect you will hear back from me in 8-12 months when the
welding, weight reductions and MOT are sorted…–
The original message included these comments:

clever engineers. However this sounds like a young guy with his
first car not as advanced as you are…


Lusstor
UK - South, United Kingdom
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In reply to a message from Lusstor sent Tue 22 Feb 2011:

A Chevy Crate Motor turns a Jaguar into a lump. That’s what they
are called in the industry…
Plus a Crate engine you could buy for 2500 pounds is the weak
sister and needs a lot to finish it off*. Due to hydraulic lifters
the valves float at 4800 RPM… They tend to be reliable but far
from exciting…
In addition to the engine and parts needed to finish it there
will be a need for a transmission, flywheel clutch, pressure
plate, throwout gear. etc. A modified Driveshaft.
*Intake manifold, carburator, distributor, water pump, Exhaust
manifolds, Vibration damper, pulley’s alternator, spark plugs,
wires, etc…etc…
The most commonly used Chevy conversion is the LS1 motor which
is several thousands more…
Oh and you’ll need to adapt the chevy to fit in the Jaguar…–
MGuar
Wayzata Minnesota, United States
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In reply to a message from MGuar sent Tue 22 Feb 2011:

Better to be called a lump than scrap! Which it currently is
(or was when I got it).

I don’t care what it gets called… Lets get the old XK in
there running and then start to look at the options.

Oh speaking of gearboxes, I assume no one in their right mind
has ever used the Auto in racing / drag or anything else?
I assume the XJ6 box is my best route…–
Lusstor
UK - South, United Kingdom
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