usually when someone gets rid of there NOS they are tired of having to fill the bottles over and over!

i have had 3-4 kits that i sold for guys,same reason.

but YES for the money its an easy way for power increase, except for NOS refills.

superchargers/turbos are always there ,when needed!

the wild guys add NOS to there supercharged cars,= puff the magic dragon.

but sure is fun, its all about to each his own!

 

Ronbros:


I have been of the mind to do a twin turbo of the type you are describing (remote mount), and to fit a nitrous system whose sole purpose is to deal with the low end lag problem: a progressive controller that admits the gas in a way that ensures the bottom end gets a lift, and the volume of exhaust gas jumps up to spin up the wheel faster.


I would think a setup like this would be pretty drivable, once tuned (yes, that's the secret sauce). And the gas bottle ought to last quite a while this way, what with little puffs now and again.


I have had this 7.9:1 flathead motor sitting just waiting for the right project....


-M

 

In regards to this subject, I have designed an alternate method of using my nitrous set up in "normal driving" (i.e. not WOT). It provides me with a very short initial burst of N2O injection if and when I want to initiate acceleration a little faster than normal. I just push the gas pedal a little harder so as to reach the trigger point, which for this use is not at WOT, but rather electronically set at near 75% of pedal travel. The duration of this initial burst is also electronically selected from a range of 0.2 to about 2 seconds. I have it currently set at 0.5 sec duration, which is enough not only to get the car going pretty good, but also to spool the engine up to its better normally aspirated HP-producing rpm's (at least 3,500 rpm), at which point nitrous injection shuts down. The end result feels like it pulls much like my XJR's does in normal driving. Not bad for an AJ6 powered XJS...

In your case you would control the nitrous burst duration with a Hobbs switch to start open and to then shut off nitrous at your desired boost PSI.

Then, considering that in this mode ("normal driving" mode) we're using only 0.5 seconds of injection, and only when the driver decides to invoke it, nitrous use is quite low, the bottle last forever and cost is low.

Cheers,

 

I've not ever had NOS. When you guys say you have to fill the bottle "often", if a fellow is a spirited driver, how often is "often"?

 

if you prepare you would never run out(if you monitor quite often).

i have been with guys who,on the way to race track, use it up, when they get there ,have to refill(at double the cost)!

most important is never run lean at WOT, low fuel pressure can ruin your day, seen many engine destroyed, with a bad tune!

anyway any thing is doable, depends on your personal preference!

 

Not only that, Ronbros, but you really must protect your engine from something going wrong, especially if you race. I do not race, myself, but I do want to enjoy my toy without risking its integrity. For that, I have designed and installed a set of protection gadgets in order to make sure that nitrous injection is shut down the very instant that something goes wrong. If you go lean (i.e. short of fuel) as you know, your pistons will melt; if you go rich (lose nitrous) you defeat the purpose because you lose that extra power you're trying to make in the first place, plus, you better not have a catalytic converter because all that unused fuel will run down and make a BBQ of the converter and possibly a fire.

A 30 psi fuel pressure-dependant Hobbs switch is the very basic device that will prevent a lean condition, should the fuel pressure drop down in the middle of a "squeeze"... In addition, and in my particular case, I use the DC output from my wideband AFR gauge (A-pillar, see gallery) combined with these voltage switch circuits to create a nitrous injection safety window that will shut down injection above (lean) and below (rich) designated AFR values, instantly. So, if for any reason you go lean (AFR flyes high), or you go rich (AFR drops down and below the safety window) power is removed instantly from both of the system's pulsoids (i.e. modulating solenoids).

Of course, this situation is not very different from the case of turbo and supercharged engines. You're still pressurizing the chamber with extra oxygen (air) and, should your fuel pump quit in the middle of a WOT stint, the system better be provided with some kind of safety device to instantly erase the condition, if not, bye-bye engine. I'm sure that this is taken care of from the ECU in some way in different cars. I just did mine my own way because my ECU has no idea what's going on as long as things are kept within an AFR that doesn't ring any (ECU) bells...

Cheers,

 

Thats a tough question. It depends on the kit your using and how often and long you hold the button down.
There are kits with as little as 50hp to multistage kits that produce hundreds of hp in addition to what you already have.
My days of multistage NOS is over for me. Not 20 anymore. I dont race anymore. I bought a 125hp kit that will produce about 100hp. That will be enough for me with the approx 375hp engine I have.

 

One thing about the Nitrous and XJS owner combination:
The typical first time installation tends to be a modest 25HP to 35HP set up before the owner decides to experiment with higher, more powerful jets. Well, let me tell you about my own nitrous first time. I can't say enough about the impression that my kitty gave me with a modest 25HP starter kit. Yes, just a 25HP set up felt like I was driving an American muscle V8, truly. It felt sooo awesome that I thought "how can I have been missing this glory"? -- Hey, and that was only my starter kit and you can choose to stay at that level forever and you won't get tired of it. Of course, all you have to do to go 50HP is to change the jets to a 50HP set, like ten minutes of your time...

So, all I'm saying is that, with just a fairly modest HP set up, you'll be in total glory and super proud of your kitty. Why? Because our XJS' factory power is relatively modest to begin with and that's why just 25HP or 35HP make such an impact. I mean, not for racing, but just for fun.

Cheers,

 

IMHO
At 3800lb with 266hp and 290ft lb of torque the V12 wont cut it.
My XJS has SBC 383 stroker. At 375hp and 400+ft lb of torque plus a small NOS kit the car should be better off.
This car is my midlife crisis. Refined with good handling and power.

 

I have nothing agains Chevy conversions. I used to have an XJ12 with a 350/700R4 and it was heaven, but that was back at my introduction to this.

I'm speaking of a 100% Jaguar with N2O injection and not necessarily drag strip power. Just a nice, unpretentious and special car with a surprising wild card for "special occasions....."

Cheers,

 

100% Jag, and the sound of 12 cylinders!! YUP, that will work!

 

Any news?

 

Just yesterday I too was reading back though this thread, and, the other forum he posted on, wondering if he has made any progress.

 

BUMP

 

*crickets*

 

SHHH, he is dreaming.

 

I haven't posted a thread about my project. I hope to hear back from the guy that started this thread. I had a real eye opener when I saw the charts published on effective compression ratio on a boosted engine relative to its compression ratio. From what I read, 30psi of boost at 6.5:1 would make 19.7:1 effective compression ratio at 1500 feet elevation. From everything I've read, a Jag V12 simply won't take that. Not for very long anyway. I'm also interested to know if 6.0 pistons really will lower the compression to 6.5:1 on a 5.3 engine. If the piston pin is higher in the skirt, it just well may be.
I did as much research as I could to build a boosted V12 Jag, and came up with a different solution. I am building a 6.0 using .200copper gaskets hopefully bringing my compression down to 9.25:1. I am deep in the throws of installing a whipple 3.3 liter SC in the valley. Air will enter the rear, and the supercharger will blow out the top. I plan on modifying intakes to "blow" back down into the engine much like GM is doing on the LS series engines. I also hope to install a water to air heat exchanger to reduce air temp. I am having a adapter made to mount the stock throttle bodies at the rear as well. It is a bold project, but I am committed to take it as far as it goes. I am relatively sure I will wind up having to tastefully modify my hood. If all goes well, seems 6psi of boost is a safe margin to enjoy the fruits of my labor. Installing pistons is next on my list. Just installed a custom set of Total Seal rings. Need to get heads reworked now.

 

hi, superchraged, nice to see someone going to force-feed a Jag v12!

if you arrive at comp.ratio around 9-9.5 is considerd about right, i dont think 6.5 is enough,even with a belt driven supercharger.

altho general consensus for a street car, 7-8 psi would be a nice final ratio, and you just may not need an intercooler at all!(save a lot of extra work). anything above that it would become manditory, and lets not forget water/alky auxilary injection!

the one thing i have reservations about, is the cylinder head being moved up .200 thou from the block.

OK lets think about that!!

are the studs long enough?

what are you going to do about the chain drive and tensioner(chain will be really tight,may not run at all,gettin scary there).

cam timing will have to be compensated for,both banks have to be in sync.

NOW my concern would be the large space between the piston and cylinder head, that can lead to a large bang if you happen to get into any DETONATION,(more gas more bang). and the large gap has no Squish turbulence, and reduced swirl of the compressed F/A combustion process.
honestly a custom forged piston is what is really needed! you want that squish area of the piston almost touching the head at 7000 revs,like .010 gap, starts out around .040 thou. then things strech out to roughly .010 or there about!


remember Jag factory pistons are cast not forged, cast ring lands crack and breakup, forged lands bend and start to lose compression leading to blowby ,usually dont self destruct.

anyhow give some thought to it! and full speed ahead

but i do love Total Seal rings, i'v used them in many engines, and have never had failures due to rings!

and a quick thought about force/feed engines , the magic number(general consensus) is power/torque really comes to life around 1 BAR, or 14.7psi, or just 1 atmosphere above ambient earth pressure, measured at the inlet manifold.

a word about cams, get it all up and running 1st with stock cams, much easier to tune and iron out the bugs, then just maybe some race cams, but truthfully just to get a GAGE PSI reading of 10 will light up your life, there aint a cam made that can give the feeling of 10 or more lbs boost!

OH yeah gotta love engines!!

 

I was all over the idea of having a set of custom pistons made. Until I asked about this project on another forum. I got a response from a pretty well known Jag guy that has pretty extensive knowledge and experience with Jag V12s. He was pretty emphatic that buying set of custom pistons was a waste of money. Then sent me the specs on a engine he built. He was adamant that Jaguar V12s, especially the 6.0, used a piston that "may" be superior in quality to almost any piston I could have made. Told me that the biggest problem with the Jag pistons, rods, was the weight of them. If I wanted to rev faster, get different rods, pistons, maybe even have the crank lightened. But for a street driven toy, the stock pistons would be fine IF I didn't go crazy with boost. He actually shaved .200 off of the crown of a set, then ran 16:1 by using longer rods, stroked crank. I had a set of custom made copper head gaskets made. I did have concerns about everything you mention. Yet, the Jag V12 tensioner when installed leaves a lot of slack, but takes it up when releasing the tension to the chain.
I have no experience in this sort of thing at all. Yet, I have tried to ask a lot of questions, read, study, and then act. All I can hope for is a really good time in the chase, lol.

 

Any updates on this?