okay, so I have an 03 s tpe r, its rated 390hp. The later s type r's are rated at 400hp. And the later XF sv8 supercharged version (with i think is the same engine) has 420hp. What is the real difference between these engines, to account for the increase in power?

I know they added more oil coolers later, but that doesnt increase power, where did those extra 10ponies come from? ecu?

I also know they added another intake track to the super charger, doubled the amount of air, 2 air flow sensors on the XF's, can this be adopted to an s type?

I guess the reason im asking is beacuse i'd like to track were they made more power, to apply it to my car ;-) before the mods begin. Any info would be greatly appreciated. thanks guus!

 

Only change I know of was from 400 bhp (Din or ECE correction, which is 390 SAE HP) to 420. Iirc it was from 2007 that vvt was introduced which probably accounts for the biggest jump. Is not to transplant to earlier cars including a dual intake/maf setup.

 

vvt? interesting... since the engine shares the same physical hardware, wouldnt it be possible to add this Variable Valve timing, by transfering an ECU out of a newer s type r and putting it in an old one. Am I missing something else? sounds 2 ez...... hmmmmm

 

Maybe possible, but not worth the effort imho for maybe just 20 hp more. You need to find the intake camshaft (is different to the standard non vvt), vvt gearing, cable looms, ECU, and if all else is equeal, you would need to make sure you can the new ECU works together with all the other computers in your car (Alarm, BPM, TCM etc).

So I think it would be easier/cheaper/more effective to swap your eaton sc to a 2.1l twin screw, for guaranteed 100 bhp more ;-).

 

IIRC, the later PCM doesn't even have the same connectors as the 03. The other issues (about programming etc) all look true, as well. Easier to transfer the entire engine, harnesses, PCM, oh.... just use the newer car

The engine now is 5.0 and 500HP I think you'll find. Lots of changes to get there. See jag web site for detailed technical articles. (XFR is kinda expensive, though.)

 

okay, so maybe its not as ez as i thought, fine. Guess ill just stick with bolt on's. 2.5 pulley, supercharger port, ecu map, think that should get around 470bhp ~ 420whp. What do you guys think. Any body actually dyno their car to get some real numbers? Ive tried searching but all i get is, "im gonna do this" or "i will do that" but not any progress.

avos, do you know an one who actually has done this conversion. Ive tried searching but have only found dead ends. Maybe I should contact Eurotoys, sems like their the only ones for this.

jagv8, i hear you on that new car, but being in college doesnt allow me to have the funds for that. Im just excited im driving a s type r! i know the xfr and new xf use the new 5 liter, completly different engine, but the 08 xf supercharged used the AJ34s, rated at 420 horsepower, which now makes 470 with the 5.0 configuration. I was just wonering how they got that extra 20 horses, probably just a fatory pulley or something.

Thank you both for all your help, u guys kick ***!

 

@TheTransporter
You can wonder how it is possible after so many years, with all these tuning options for the Eaton you do not see good rwhp figures., all I can say is that I don't wonder anymore ;-).

I also tried in the early days of my XKR ownership to tune my car with the Eaton (pulleys/porting), but as the gains were very limited, I go so fed up and started to go my own way. It didn't take long to realize that another supercharger was needed, and there is only 1 ;-).

One should not underestimate the power of the twin-screw, it offers some major benefits compared to the roots type M112.

Just to name 3:
1) Uses less power to drive, easily 30-40 whp depending on setup so this energy doesn't have to be created by the engine, and comes free to the wheels. If you start spinning the Eaton faster, it will consume even more power, and put also more stress on your engine.
2) Is able to provide pressurized air at a much higher efficiency and lower temp.
3) Fuel consumption will stay low. Once you start spinning the Eaton faster, your fuel consumption will drastically go up.

I have just been able to pull 550rwhp on my car (and there is more to come), but immediately have to disappoint you, as this will not be able with the STR with just a TS conversion due to the limited space.

I have converted 1 STR to a twin-screw, and that one has already done 420 rwhp (was in high temperature, no ECU tune or any other modification). I think I can push this one with just an ECU tune to 450 rwhp. Then maybe with other mods (sports catalyst, intake mod or more) you will be able to get even more, no doubt.

If you want more than 400 rwhp safely for the engine, then the TS is the way to go. But this may not be something for a student budget...

 

Regarding the VVT, it bugs the hell out of me that the N/A 4.2L has it but the earlier S/C cars don't.

Now, the heads are exactly the same part number between the N/A & S/C VVT cars, and the inlet camshaft is the same p/n between the N/A and the later S/C with VVT. The only major differences to bring VVT being the Secondary Timing Chain setups, the Module Carriers, the VVT units themselves along with the solenoids etc.

The ECU controls the valve timing, so some additional wiring would be needed, as well as a re-tune or maybe using a later model ECU, again with a tune or forcing the later model map by changing the file name.

Other changes are higher volume oil pump, and an oil temperature sensor, since the oil needs to be within a defined temperature range in order for the solenoid to function properly, and a different oil cooler (i think).

So the easiest way to make this work would be to find a donor N/A 4.2L engine, swap the heads and timing gear, and then look at the anciallary stuff; oil pump, temp sensor, ecu/wiring.

I agree it's a lot of messing around for only 20HP, however...

What would the gain be in conjunction with the twin-screw? More than just 20HP I imagine. And with the engine half-way dissasembled to change the Supercharger, a little more work to change the heads & timing gear isn't such a stretch.

Avos your engine has the VVT from the 4.0L heads right? If so i'd be convinced that also contributes to the HP numbers you see.

On it's own not really worth doing but maybe worthwhile as part of the package?

 

Cambo, Avos's swaped in a 4.2 s/c into his 2000 XKR. He adapted a 2.1 L twin screw blower. It was a 230 hp (635 chp/535 rwhp) upgrade. The exhaust is stock. We want a twin screw!

 

Yes I know about the twin screw...

I was under the impression that Avos has a 4.2L block with the 4.0L heads on it....

For some reason I thought the AJ26S & AJ27S had VVT?

But then I look in Wikipedia (cause that's always right) and "The supercharged engine did not use variable cam timing as the normal benefits of improved volumetric efficiency are not noticeable on a boosted engine"

So it's a pointless exercise and i've answered my own question in the meantime...

 

From 2007 or so, the AJ34S did have also VVT, but very briefly, so as usual Wikipedia isn’t correct ;-)

Maybe if you use the cams/vvt unit from this model, and you use an piggyback ECU that is able to handle/control the VVT it might be possibe. But it will be lots of work for little gains, though certainly a fun project though.

 

Oh yeah, the later models

Dunno about a "fun" project, but if it squeezed out more horses and the parts located cheap enough then why not.

Piggyback ECU? The later models already have the correct program to control the VVT, so surely that would be an easier starting point?

 

Good point, but you need to find if there were more changes, and then the new ECU needs to work with the rest. I don’t have this knowledge for these models, so you need to dig around to find it (althoug these cars already use higher flow injector for instance). If the changes are minimal (and cabling will not be an issue), you can do some playing around of course with some units and your IDS. Not sure what will be easier though, so if you have the time, probably best to focus first then on the differences in these models.

 

Sounds a lot of trouble and besides what extra 20HP is the VVT supposed to make? Seems an urban myth, being kind.

 

It was just an idea, and if VVT brought 20HP on a stock engine, maybe more on a worked one?

I don't know, I was thinking about it the other day & then I came across this thread.

But if the opportunity came up...?

 

It really appears it didn't add 20HP. Jag docs say it was added for reduced emissions. I haven't found any claim by Jag that it added 20HP. If you have, please point me at it!

 

I never looked much further than post #2 in this thread...

 

It appears to be wrong. The various jag Technical Guides say VVT added to reduce emissions. The sales brochures do not add 20HP. Etc. As you can easily read on the net, SAE et al changed their way of calculating HP and as a resut many cars changed their apparent HP, without actually changing at all.

 

The 4.2L XKR got 420HP towards the end didn't it?

Variable valve timing seems to have brought more power to a number of engines over the years, i remembet when Ford Australia brought "VCT" out on the 4.0L inline six, there was quite a jump in power.

Asking for trouble quoting Wikipedia again but have a read Variable Cam Timing - Wikipedia, the free encyclopedia

Hondas VTEC certainly worked wonders, and for sure the 3.0L in my X-Type benefits in the top end of the rev range...

Interesting that the Ford VCT article says intake cam brings power, exhaust cam reduces emissions...

 

Pass. It's the STR I mainly know in jags