I like the idea of rear mount turbo, my only concern is lack of space around the trans for 4 sets of pipes.

What size pipes would you run from front to back and back to front?

 

2" dia. would be sufficent ,2 hot pipes and 2 cold pipes, 2 GT 28 series Garretts would work , around 70mm cold sides, remote mounts require a small turbine and a large compressor, we are not after the super-ultimate power maker.

and with under pipes, not recommended for off road running!

 

Exciting ideas in this thread. Anyone heard from Shaun?

 

for anyone interested ,STS turbo systems.com

 

Shaun hasnt posted since November. I guess he was put off by members negative comments. He seems to have a great idea that we all could have learned from.
Its a shame.

 

if he gets it up and running i'm sure he will tell us!

 

I'm sure he's probably just busy. Damn, Ron - those kits are pricey! I keep hearing about how much cheaper it is to hot rod American cars, but you can get a screaming supercharger kit for a 928 starting around $5k!! Not quite an apples to apples comparison, but the end result is the same.

 

flint hot rodding american V8s are cheap in comparison of most foreign engines, but when you go into the forced induction world ,it makes little difference who makes the engines. they just gotta be strong.

but and a big BUTT, what else type of mods can give the % of power that a pressurized inlet manifold can do? breathing modifications take on completely different priorities. quick reference; theory says an N/A engine on the intake stroke has 14.7 atmo. pressure pushing into the cylinder, now lets up it to force feeding the bitch, like a manifold has 14.7 PSI pressure, theory says 100% increase in power,(it dont quite work out that way,but just add more pressure), it would take a lot cams,pistons, bores and strokes,ports,TBs,valves,headers,pipesETC, to do that,truth is cant be done ,CHEAPLY! not sayin a good supercharger kit would be cheap ether.

truth be known,back 20 odd yrs ago when building my engine, if i knew what i know now it would have been turbocharged, i did know about turbos but never to the extant that is available for components today.
the whole thing has exploded with new techniechs and unbelievable knowledge!

 

quick food for thought, if 15psi in the manifold would give(theoreticly), 100% increase in power, then 30psi would givw 200%, and 45psi would give 300%, more power!

this is just to think about why superchrging has become populer with the factory cars

 

The problem with superchargers is that they can take up to 100hp just to run.
Turbos are free power without powerloss from running it.

 

Bc quite true, in the beginning turbos were called turbosuperchargers, later shortened to turbochargers!

engine driven superchargers(today) have more imidiate response, while turbos give more top end, but both types are far better than just 10 yrs ago!

 

I agree. Back in the day I had a 440 with supercharger and the bottom and midrange were incredible. It would launch like a fighter jet. The top end, not so much.
Not long ago I had a Mazda 323 turbo awd 4 cyl 2.4 L That turbo made the car. It seemed to want to run faster and faster. Its ability to increase power was incredible.
I was sold on turbo power after that.

 

And to superchargers and turbochargers, I add a third option, Nitrous.
On my '94 XJS with the AJ6 engine I have a progressive controlled nitrous injection, currenly producing 130+ HP over and above the stock 219 HP, approx. total of 350 HP. I have clocked the car at 5.2 seconds 0 to 60, same as my XJR, only that it appears to pull a little stronger than my XJR, which is because nitrous is instantaneous power, strongest when the intake cycle is the longest (i.e. at lower rpm's).

The system is from the Wizards of Nos, UK, whose owner (Trevor) is the guy who raced (1/4 mile) and beat a formidable bunch: a Corvette, a Porsche 911 Turbo, an NSX, a Ferrari 360 and a Venturi 400 GT a few years back. For this, Trevor set up an earlier V12 XJS (looked old and beat up) with a 500 HP super nitrous set up, which was shown on BBC's "Top Gear". It is odd to see all those sophisticated cars being beaten by that old rundown XJS. The closest second car was the Porsche, about two car lengths back. This race actually took place some time after I purchased and installed the system in my car.

Cheers,

 

Totally forgot...

Of course, at a fraction of the cost of S/C or Turbo.

Cheers,

 

No such thing as free power, turbos cause back pressure if small enough to spool quickly and major lag if big for topend.

I have owned 5 turbo cars and 2 supercharged (all factory, no aftermarket) and the throttle response of the supercharged was far superior to any of the turboed cars. A twinscrew supercharger (as was in my Mercedes C32 AMG) was by far the best FI of anything I have driven on the street.

My Merc was totally stock 350hp my neighbours Ford XR6 turbo making 600hp was slower to 70kmh, I could take him at the traffic lights every time, by the time he was shifting to 3rd he was gone but speed was well above legal limit.

For the V12, highish CR 9:1 and low boost should give reasonable response and good topend.

 

Nitrous would be a great and easy option, unfortunately it is illegal in every state of Australia to have hooked up on the street.

 

i have raced some guys with nitrous, and on a late night race , they run out of nitrous, then there back to regular N/A. all you gotta do is run after run till they start to lose nitrous pressure.
but some have extra bottles, and wouldnt yah know one is empty.

today the variable geometry turbos seem to be the hot set up, plenty of bottom end torque,and they merge into plenty of top end speed.

they do work ell when done properly!

but no doubt for a street road car engine superchargers are the most practical, the factory knows what works for there street cars, turbos for racing ,,superchargers for street.

 

I bought my neighbours nitrous system and will be installing on my SBC stroker that Im installing in my XJS at this time.

 

Well, if the guy knows what he's doing it'll be quite silly and totally unnecessary to put himself in such a situation. If you're planning to race with nitrous, you should plan well ahead of time how much you intend to race that night and to determine how much nitrous you'll be using, including a safety margin.

In my case I do not race, not with a heavy convertible. It's only for fun and for the "ocassional" encounter, particularly when you're "invited" by somebody who inevitably will end up in total disbelief, as the XJS does not necessarily project the image of, say, a late Mustang with a probable blower under the hood, or an M3, let alone a Vette... but rather the image of an "old man's car" which should be easy to beat. -- Uh, an old man's car, perhaps... easy to beat, nope, not in this case...

Cheers,

 

Nitrous on your 350 V8? Man, everybody out of the way!!

Jeez, if I do 5.2 sec with my "slow-to-begin-with" 247ci six engine (aka 4.0L) plus 130HP jetting, just imagine similar nitrous jetting on a 350ci V8, wow!

Let us know how it goes.

Cheers,