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I know that Andy has upgraded his XJR with M112 from X308 XJR and Dr Jag (Greg Parson) had X300 XJR running with Eaton RVT1900. Both projects have involved moderate to heavy fabrication.
But has anybody investigated either M90 /M112 hybrid or MPX casing with M90 rotors? (Magnum Powers "MP Extreme" (MPx) - Magnum Powers )
These are something that the Supercharged GM 3800 growd and Buick people have been discussing and using these. I did not have time to even skim half of the discussions floating around the web on these
Obvious question is that is the jaguar short snout bolt on to the normal M90 casing or not? or is there need to fabricate a shorter snout? (I have not looked the dimensions that detail, just eye balled some photos) and maybe MPX case is higher.
other possibilities is gen V m90 with Jaguar short snout or porting the original (I am guessing the XJR M90 is gen 3) ? Based on the discussion around the net these should be flowing about the same, yet I not seen real measurement data.
Most likely any of these would be beneficial to do with less restrictive intake /exhaust and higher capacity injectors which would then lead to ECU reprogramming?
For those curious, attached is the "Dr Jag" article that was referenced above.
Will be interesting to see what replies follow.
I don't know anything about the Magnum Powers MPx case, but the first thing I'd wonder is if it dimensionally the same as the OEM M90 case and "bolt on" and will fit the engine and intake without modification.
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Last edited by al_roethlisberger; Mar 22, 2016 at 09:40 PM.
Yes and from what I've read a properly ported gen 3 is roughly equivalent in efficiency to a gen 5, and a gen 5 is essentially maximized as stock and doesn't benefit much from any additional porting.
So while we don't have access to installing a gen 5, it's not really a detriment as one could get their gen 3 ported and obtain similar efficiencies.
Has anyone explored replacement of the Roots blower with a Twin Screw type supercharger like Roger Bywater discusses on his aj6engineering site? I am thinking of replacing the M90 with an equivalently sized Autorotor or Lysholm when time comes for supercharger rebuild.
Curios if anyone has explored replacement of the Roots blower with a Twin Screw type supercharger as suggested by Roger Bywater in his supercharging articles on aj6engineering ?
I am planning to explore this when the time comes to rebuild or replace the M90.
Curios if anyone has explored replacement of the Roots blower with a Twin Screw type supercharger as suggested by Roger Bywater in his supercharging articles on aj6engineering ?
I am planning to explore this when the time comes to rebuild or replace the M90.
Not that I am aware of.... one forum member over in the X308/X100/X150 sub-forums sells twin screw kits for subsequent models, but not the X300.
Along with custom designing a kit, one of the issues is also ECU programming if intake exceeds a 10% increase. Our resident expert XJREngineer (former Jaguar engineer) can explain and do this for you.
There is really not much out there for hot-rodding the X300, at least "bolt on". It was made for too few years and too long ago.
The only real aftermarket left is the lower SC pulley from Powerhouse, but there are caveats with intake charge overheating that apparently are hard to overcome. So it isn't very popular on the X300. Do a quick search on "supercharger pulley" (or similar) for loads of information.
Andy fitted the larger M112 SC to his car, but that took some significant modification and custom fabrication.
The other quick win is an "Andy Bracket", XJREngineer makes them.
Understood. The main reason I am interested in exploring use of screw type is for improved overall efficiency of Screw chargers over Roots, which also includes lower intake charge temperature.
I fitted one of Andy's 5 degree advance brackets back in January and the throttle response is significantly improved. Also swapped the differential to non-supercharged 3.58 ratio diff, big smile improvement there.
Understood. The main reason I am interested in exploring use of screw type is for improved overall efficiency of Screw chargers over Roots, which also includes lower intake charge temperature.
I fitted one of Andy's 5 degree advance brackets back in January and the throttle response is significantly improved. Also swapped the differential to non-supercharged 3.58 ratio diff, big smile improvement there.
Yep, understand the benefits of the improved SC efficiency well. Unfortunately when I last asked if any X300 "twin screw kits" were available from our forum colleagues, the answer was nil. So it may be possible like anything with enough time and funds, but so far there is no bolt on twin screw option AFAIK. That being said, if you discover some alternatives, definitely let everyone know!
Now changing that diff ratio probably is one of the biggest "bang for buck" performance improvements for off the line acceleration since the XJR's is taller than the XJ6 ...which BTW, always seemed odd since Jag wanted the XJR to show up the other sporty sedan competition. I guess it was so they could maintain top speed bragging rights? Dunno.
I've thought about updating my differential gearing, but I do a lot of highway (almost exclusively) driving so that would be a hit to fuel economy at a relatively high expense. So other priorities have come to the fore Where did you get your gearing, and what was the approximate cost to install that gearing into your LSD differential?
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Last edited by al_roethlisberger; Mar 28, 2016 at 04:01 PM.
After installing the 3.58 diff the car was a "neck snapper" but did run about 3000rpm at 75mph which was not economical. When I decided to replace the Goodyear F1 Max tires with something a bit more cushy I discovered that the previous owner had installed 255/40ZR17's (25" height), instead of the 255/45ZR17's (OEM Size, 26" height) which effectively made the final drive even lower. I just had a new set of Continental Touring in 245/50R17 (26.6" height, same as XJ6) installed when I had wheels refinished. So I am nearly back to where I started as far as final drive ratio goes, but the ride quality is much improved.
I purchased a whole differential from '96 VPD at a local "Pull it yourself" salvage yard for $150.00 and then swapped the gears out myself with help from a good buddy.
After installing the 3.58 diff the car was a "neck snapper" but did run about 3000rpm at 75mph which was not economical. When I decided to replace the Goodyear F1 Max tires with something a bit more cushy I discovered that the previous owner had installed 255/40ZR17's (25" height), instead of the 255/45ZR17's (OEM Size, 26" height) which effectively made the final drive even lower. I just had a new set of Continental Touring in 245/50R17 (26.6" height, same as XJ6) installed when I had wheels refinished. So I am nearly back to where I started as far as final drive ratio goes, but the ride quality is much improved.
I purchased a whole differential from '96 VPD at a local "Pull it yourself" salvage yard for $150.00 and then swapped the gears out myself with help from a good buddy.
Maybe the subject for another thread, but would be curious to know how hard it was to change out the internal gears versus the entire differential.
So how was the RMP and efficiency at 70-75Mph once the correct sized tires were fitted?
Maybe the subject for another thread, but would be curious to know how hard it was to change out the internal gears versus the entire differential.
So how was the RMP and efficiency at 70-75Mph once the correct sized tires were fitted?
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2700-2800 at 75. Still a bit early to tell much about efficiency, just refilled 1st tank since tire went on yesterday. So far my running average for the last 2 months has improved by .3 mpg.
Now changing that diff ratio probably is one of the biggest "bang for buck" performance improvements for off the line acceleration since the XJR's is taller than the XJ6 ...which BTW, always seemed odd since Jag wanted the XJR to show up the other sporty sedan competition. I guess it was so they could maintain top speed bragging rights? Dunno.
Nope, it was for magazine 0-60 numbers. In a manual transmission car they could do 0-60 with only a 1-2 shift with a 3.27 diff. With the typical automatic 4.0 ratio of 3.58 a shift to third would be needed as they would hit the rev limiter in second. The extra 2-3 shift produced slower times than the off the line acceleration handicap of the taller diff ratio.
Not important in an auto car, but the auto was slower than the manual and Jaguar was looking for headline numbers. I think the auto was a second slower to 60 than a manual? Can't remember exact numbers.
Dumb question, but are all the XJR diffs LSD?
My XJR is a manual, but converted from auto by a previous owner
It feels LSD when the traction control is off
I have been considering a different swap to lower the ratio
I'm in NZ where the speed limit is 100 km/h
If caught over 140 it is loss of licence time
So a theoretical top speed of 250-260 is not much use to me, but more acceleration is
Has your research or digging revealed any new facts on the supercharger topic?
I’m planning to take my M90 apart for service in the near future, probably also some port job but I’m a bit tempted to instead swap it for the M112.
Would be interesting to find out if the Jaguar M90 short snout in some way is adaptable to any of the M112 housings, imagine it could simplify things at least in some aspects.
Add a pic of the Jag M90 if there is someone with knowledge of the M112’s, bolt pattern etc.
Supercharger upgrade options
Where did you get your gearing, and what was the approximate cost to install that gearing into your LSD differential?
