Language, should be more careful when writing things, it’s just not my thing being somewhat dyslectic.

I only have the XKR, but I placed 70Kmiles ago a 4.2 engine in it (see my album for more details), and this is what I was referring too.

The 512rwhp was with normal fuel (and no aids like alky or nos), with race fuel there is even more, but this is already ok ;-)

 

@Qikcat,
Keep an eye on your a/f ratio (fuel pressure), as I am not sure what the max is that single pump can deliver.

 

No worries! Nice car

Who else hasn're looked at Jaguar Forums - Jaguar Enthusiasts Forum - Garage Portal .... well worth a read!

hmm, that should be Brembo not Bremo (and you could swap in re-ground for re-grinded)

Which PCM is in it? The one it started with or the one from the 4.2? (And if the 4.2 then which one?)

edit: "only have ... XKR ... 512rwhp" hmmmm, a new meaning of the word "only"

 

There you see language is not my thing ;-), thanks for finding the typos!

Am still using the Stock ECU, and stock tune even.

 

I'm guessing English is not your first language so you do really well!!

I don't know that era XKR's PCM, who makes it? Is it Denso and 32-bit? Does it have a CAN bus?

 

Thanks for the heads up, any idea where i will run out of pump or how far the ecu will push the inj duty cycle?

I have anticipated running out of pump. I have a kennybell boost-a-pump from another project i could go to or may just do a dual walbro intank setup if I go that far into it. I would love to just throw on the bap and be done. I am thinking a ported maxed out 112 will see 450ish at the wheels based on the data from other platforms and taking into account our setups limitations. That of course assumes we keep the heat down to a reasonable level and keep the ecu happy. That should be at 16psi.

I am going with the killer chiller for sure, simply because its a guaranteed way to combat the heat. I have also considered a rear mounted tank for extra capacity, more cooling and the ability to ice at the track. Not to mention the alky I already have and the nitrous when I use it (they operate separately and never together).

I would be happy to just buy your TS kit and call it a day as 500rwhp would be about where I would be happy at. I just don't want to screw with it on my own and have a never ending project. My mods will be simple pull the car down a week, swap parts, and be back up and running. I could have bought a E39 M5 for the same money and had a 600hp car with proven parts but just something about the jag and nobody expecting it that I like

 

As I see it the PCM does this:
1. if it can use the O2 sensors, it does, and will do accurate fuelling
(this won't happen at WOT)
2. otherwise it uses the MAF as its main indication of fuel needed, trimming it as the other sensors show (IAT, ECT, BARO, IAT2, etc but not the O2s)

It'll have no problem with the injector pulses.

Because of the above your AFR will be wrong in actuality if the MAF is wrong

The upstream O2s are AFR sensors but I understand ordinary OBD tools won't report them during WOT - never looked myself nor checked whether AutoEnginuity can report them during WOT, sorry.

It will not know that alky / nitrous are present (and are not air). If you fed them in before the MAF (for the sake of debate) the flow would be assumed to be air. Chemistry suggests to me that nitrous has lots more O2 than air so ideally you'd like to boost the MAF reading artificially when adding nitrous, so the PCM would then add more fuel. (I don't know what alky is, chemically lol)

Hopefully avos or someone will point out my mistakes/omissions!

 

The nitrous is post maf but has its own fuel source (wet kit) so the ecu dose not need to add fuel for it. You tune that fuel with the nitrous jetting by AFR.

"Alky" is me being lazy and not typing out water/methanol injection LOL. If I don't need the extra fuel in all actuality it will most likely be 100% water inj. This is also post maf but is used for cooling only with water and if a 50/50 mix of water meth is used its equal to about 110 octane race gas so f nothing eles it will be fat. The limited tuning is the main hurtle in all this even with the piggyback.

The question about duty cycle is because I dont know at what point the stock ecu says 80% dc is enough? Or will it run to 100%? Basically trying to decide where i run out of inj.

 

Are the injs anywhere near the limit? I suspect not, especially as people tend to see rather rich figures at WOT, but would be nice to know.

 

Well since I need 42lb inj to support 550 crank hp at 80% duty cycle and 45psi of fuel pressure (450 cc for you European types ) and 550hp is the bottom end of my power goals the question is, what size inj do we have and at what FP. None of that even touches on the pump it sounds like may need to be addressed, btw I am also taxing the pump doubly with the nitrous tapped off the stock fuel system.

 

Can you get 550hp yet use the M112 and the 6HP26 and the current rear diff? I'd guess no to all of those but the TC kicking in, with trq reduced due to that. You're up for a challenge!

 

550crank should be easy that's less then 450 at the wheels I should be well north of 500 with the spray. Ported 112s on cobras and lightings make 550 at the wheels commonly so I think I am being conservative at 450rwhp. Time will tell, maybe I am for more of a challenge then I think but at the end of the day its just a internal combustion engine just like the rest so power should not be an issue. The rear end now you may be onto something there!

It was hot on my 368rwhp pull and i have a few more mods now. I would bet a good clean dyno pass and I only have about another 70 or so ponies to go to 450.

 

@Jagv8
The ECU and CAN of the AJ27 engine are alike for the AJ34 of the STR, both have dual chips which can work individually on different tasks, both are Densos so the programming is also alike in the sense that they are torque based. The main difference is the AJ27 is 16bit and the AJ34 is 32.
I’ll take it the NOS will only be used at wot, and as that is outside of the closed loop, fuel strategies will indeed not be affected.

@Qikcat,
Don’t forget to add the power needed for the supercharger, so a stock 400bhp engine, has to produce about 460 bhp (60 to drive the supercharger). The faster you spin the Eaton, this power consumption
gets more exponentially higher NOT linear…

I think the injectors are 52lb ones, and run somewhere in the 55 psi or 65 (would need to check).

Am not sure where the max is the fuel pump can deliver, but it isn’t endless. Remember that when you increase boost the fule pressure most compensate, so the pump must not only deliver more fuel as you add more air, but also has to deliver this at a higher pressire...

The pump is pmw controlled, and the ecu will also check the actual fuel pressure in relation to the duty cycle of the pump, so although
I think you could modify the pump slightly, it might be tricky. Just have a look thru the DTC’s related to the fuel system, that will give you some idea what all will be checked. So you can’t just make a dual pump setup, I would think maybe a slightly stronger pump, or the BAP (possibly connected directly to the pump).

Can certainly advice to get a good reader (ideally WDS/VCM, as they can read all at high speed), that will enable you to check all sensors, so you will know if you could run into issues.

 

Thanks. I was wondering when 16-bit Densos moved to 32-bit in jags and that fits well.

Ooh, 60hp for the Eaton! Ouch. That TS sure looks attractive.

I've a suspicion that only a CAN reader will get the WOT AFR etc values on an STR. It's a non-standard software protocol (perfectly alllowed because this isn't SAE OBD II emissions data), which of course WDS/IDS and AE know but most tools do not. I don't know if it's even more proprietary and thus not supported by AE (but I'm nosy so eventually may look LOL). Snag is that even a used WDS is expensive

 

Made some estimates a while back, so when you would go for a 3psi pulley (so assuming you run it about 14Krpm), your engine gets 60 HP more, but at a cost, the Eaton will at least use 30HP of that, and you probably lose another 10 or 15 HP due to the extra heat, netting you about 15 to 20 hp. And the other cost is that the system heats up so much, that your power will degrade much quicker than stock the longer you use it. So heat is something you need to combat if you go the Eaton road, but there isn’t that much you can do about the power consumption of the unit itself, only if you could reduce the intake vacuum.

Have been in contact a couple of years back with Jay form AE when he developed the Jaguar option pack, and he was surprised to hear that I could get O2 sensor info at open loop where he was not able to. So far only the IDS/WDS can read that (not sure if AE can do it now though). On ebay you still can get occasionally a WDS unit for $300 or $400. The Chinese VCM’s can be had cheap now since the mongoose is available; have seen offers of $380. Some have issues with them some not, and I belong to the latter as mine has worked for many years now. These tools are invaluable if you are heavily tuning your car imho.

 

I have been looking at and bidding on the WDS units as they come up. Haven't hit on one yet but as the project gets closer I may have to suck it up and just get one at the asking price. I agree it is a necessity for knowing whats really going on.

The drawback to any supercharger is the cost to spin it, that is why we went to turbos on the race cars, driving an 18-71 blower at 36# really cost some major HP. I plan to overdrive the 112 from the crank with a custom pulley instead of under driving it from the top. Same power loss but less stress and no slip and I can pick my boost. The Eatons on other platforms have been proven to run out of steam at 17-18psi, I am stopping at 16psi personally. I average 15psi now so should not cost much more power but with the port be moving more air. The guy I used for porting gets 35-40 rwhp proven many times on the Cobras with the 112 so time shall tell.

I agree that the heat is the key and the chiller has worked very well in other platforms to combat it, seeing max IAT temps in the 80' range post blower on wot track pulls and quickly cooling. I guess we will try the boost a pump on the fuel and see how it works. If the ecu dose not step in it should give me enough pump volume and pressure to reach my goals, at least for now since it seams the twins may cause issues. This ECU fighting you at every step is a PITA for sure!

 

The water/meth injection isn't enough to combat the higher temps from the 3lb pulley?

 

Are the main things of interest (to a tuner at WOT) IAT2 and both AFR (wideband) O2 sensors?

Do you also need to know the fuel pump DC (duty cycle)? hmm, fuel pressure? Injector pulse widths (or similar)? LOAD?

OK, what else?

$300-400 is less than AE costs so WDS would be worth getting (not for me as I already have AE and besides am not trying to get more power).

With a VCM do you also need a Mongoose (or similar) or is just a Mongoose enough?

 

@Qikcat
I call it more a challenge, there is always a way and sometimes you need to be inventive. The reward is nice when you have beaten the system ;-). Just keep an eye on the fuel delivery, as it might just be enough for what you want to achieve. You could always have another fuel pump just for the NOS, that way you lessen the burden on the stock pump. Haven’t yet investigated if the BAP can work, but if you can set the voltage, and it can work with a PMW voltage delivery, it might just work. Otherwise I think a slightly more powerful pump might also do the trick. As said not too much for both solutions as there is a rational check by the ECU.

@JagV8
And you want to know more, Timing, vacuum (MAP value), load isn't interesting as that is based on original MAF values, but you would be looking at the MAF. And all the other sensors that help diagnosing if the engine is running properly/healthy.

VCM is the Hardware, IDS the software, and Mongoose has replaced the VCM as hardware. For both you need a laptop.

 

I have enjoyed watching this thread and the way it has progressed. What a wealth of information from some cool car guys!

Most of you know I had pre and post dynos during my exhaust mod last summer. During some of my dyno pulls my AFRs actually appeared to be lean. Most of the threads on this forum state that our STRs run too rich for detonation protection. The ratios were read via an exhaust sniffer, not connected direction into the O2 bung which is the better way of reading AFRs.

Attached are the pre and post dynos. Let me know what you guys think...too lean???

Note:
I changed my fuel filter again last week from a Puralator to a Fram because some Puralator fuel filters pop off the fuel line's quick connects. This actually happened to me on the road once and at the track once before had the opportunity to put on wire ties and find this information...

Reference:
Item Affected: FUEL SYSTEM, GASOLINE
Date Announced: 6/23/2006

Description of Recall:
CERTAIN AFTERMARKET FUEL FILTERS SOLD UNDER THE PUROLATOR BRAND NAME, P/N F65277, SHIPPED FROM JANUARY 16 THROUGH JUNE 2, 2006, FOR USE ON THE ABOVE LISTED PASSENGER VEHICLES. DUE TO INCORRECT DESIGN, THE QUICK CONNECTORS MAY NOT FULLY SEAT WITH THE TUBE INTERFACE, EVEN THOUGH THE PERSON MAKING THE CONNECTION MAY BELIEVE THAT THE QUICK CONNECTOR IS FULLY ATTACHED.

Action Needed To Fix It:
UFI WILL NOTIFY OWNERS AND REPLACE THE FILTERS FREE OF CHARGE. THE RECALL BEGAN ON AUGUST 4, 2006. OWNERS MAY CONTACT UFI FILTERS USA AT 800-230-5876.

Fram had a similar issue to but mine seems to hold...
CERTAIN REPLACEMENT FUEL FILTERS, FRAM BRAND NAME P/N G3727, WITH DATE CODES X52911 THROUGH X60801 SEQUENTIALLY OR X600141 AND A MEXICO COUNTRY OR ORIGIN MARKING ON THE FUEL FILTER HOUSING MANUFACTURED FROM OCTOBER 18, 2005, THROUGH MARCH 21, 2006, SOLD FOR USE ON THE VEHICLES LISTED ABOVE AND ON CERTAIN SCHOOL BUSES. (TO SEE THE SCHOOL BUS ENGINE SIZES, CLICK ON "DOCUMENT SEARCH" AND THEN "BUS APPLICATIONS"). THE CONNECTOR ON THE FUEL FILTER WAS NOT MANUFACTURED TO HONEYWELL'S SPECIFICATION. AS A RESULT, THE O-RING MAY NOT SEAT CORRECTLY ON THE FUEL LINE.