I am speaking of dyno charts posted here and charts I looked through at two diffrent dyno shops. As I said before it's no revelation they are pig fat rich. If you want to know what yours is dyno it and see for yourself. I shut mine down a bit early I am sure if I rolled in it early and ride it out mine would be in the high tens.

 

I don't recall any dyno charts for our cars showing such low A/Fs. So, it IS a revalation for our cars. I'm looking forward to seeing such a chart.

 

Well mine is posted here, ask mafioso to post his it's in the 10s and as I said I have seen three other at the various dyno shops I use, or just don't belive me since I have some motive to make it up? Either way, maybe no one tunes STRs for a reason.

Edit: also pm avos he has commented many time on the rich A/F on the 4.2 sc motors

 

Yeah, the fact that they were purchased by 50 year old doctors... LOL

Now back to our regularly scheduled program...

Take care,

George

 

I'm very well aware of avos and his posts. What I've seen him say more than once is that the stock tune is good and safe.

I'm trying to find out about your claims of the 10.2-10.5 A/F range because I don't recall avos or anyone else saying that. Your own post says the worst was 11.6 doesn't it?

I've no reason to believe or disbelieve you as yet as where is the evidence either way?

 

I also said in my previous post it was overly safe. No one ever said fat wasn't safe just that it wasn't a way to making the best power. I have taken from a few of his post here and on other boards it runs rich?

I am making no "claims" at all simply stating what I have witnessed. I am not trying to sell you on the idea, or anything for that matter. If you believe the stock computer is good enough then your all set. You asked where I had seen it and I answered. I looked at Mafioso posted charts and didn't see the one with the A/F but I have spoke with him about it extensively about it. The charts I have seen with A/Fs in the 10s make what most would consider the right rwhp numbers. That leads me to believe if the cars out there dynoed who do not record lambda are in the same ranges as a genneral rule chances are good those are also not running ideal numbers. Granted its a generalization with many variables.

You are correct I did mistype 11.6 its actually at 11.2 if you look at the chart posted with it. As I said I was pretty happy mine was not in the 10s also. That was at 5800 since I was not sure how quick the limiter would kick in then, its 11.0 at 6K. Also were not just simply talking about being able to make more power. Power under the curve, tip in etc... as well.

What types of numbers or who's charts are you seeing to make you believe that most are running better ratios? I am just going of the sample group I have seen. Maybe someone like AVOS who has dynoed a lot more of these cars can chime in on his findings? Either way I am doing the piggy for my car since mine needs the fueling changes and may need much more when the water goes to it and I also need to be able to retard the timing, a switched TPS/rpm controlled output and logging.

 

You seem to think I believe (or have stated) a few things which I've not said I believe (and have not stated).

Actual numbers for STR A/F under boost are astonishingly rare IME of many posts here and elsewhere.

They're so rare that yours stood out but then when you referred to 10.2-10.5 I was unable to find any other reference to that range at all and no dyno chart showing that range. Understand I'm not saying no such data exist just that I don't recall anyone stating it until you did.

With almost no concrete figures, debating the stock tune becomes a challenge!

 

Then I misunderstood your comments. I understood you to be saying those were out of the realm of normal, assuming that other sheets showed different numbers. My apology's if didn't understand what you were saying.

I will see if the dyno owner with the other charts is ok with me printing and posting them here. I also text Mafioso so maybe he will chime in at some point with his. I am going to be at BI performance next week and after talking with their tuner about the numbers he has seen on their dyno he should also have some charts if he is willing to let me have them? Also maybe Avos has some charts and we can start making a data base. I will be very shocked to see anything other then what I have seen in my sample group and in the conversations I have had with the few guys that have dove into the 4.2Rs.

I will be putting my car back on the dyno hopefully next week to see how the extra boost affected the A/F and power one way or another. I will venture a guess the ecu is dumping even more fuel now but its just an educated guess as of now. Just waiting for the weather to cool since I am trying to at least mach the conditions as well as I can from my baseline.

Also as I have said from the get go its not just debating the max power A/F tuning. It is adding the flexibility to change the car as its modified in real time. Getting real numbers and modifying them to make that individual car preform well at all ranges rather then shooting super safe for an international market with tons of variables. Not to mention the other benefits.

 

No worries. It'll be interesting to see how it works out.

Better cooling of the boosted air may tax you

 

qwikcat, how far out are you from altering the ECU? In other words, would you advize me to hold off on a generic/off the shelf ECU flash tune?

 

I spoke to mafioso a while back and he did say that his was well into 10's on his car. At some point I'll run my car as well to see where it is with the alky injection.

 

I should have the ecu on Tuesday. I am not sure at what point I will have a few days time to patch it in, setup the base maps and tune it all.

Honestly your looking at maybe end of June time frame. Keep in mine unless you want to bring it to me or have the skills yourself or local the harness (assuming they will build one) would most likly be many months out. Just really depends on what your time frame looks like.

Qwik I hope to have my inj in and running in a few weeks so we can kind of compare where were at with it. I think I have settled on a small pre blower shot for cooling and the slight boost bump and two med nozzels post blower into each charge cooler also running a 50/50 water meth mix. I am excited, this should take care of a lot of heat dropping IATs and get enough octane to keep the timming up. When I have the ablity to lean the car out some I hope it will keep me from having to retard the timming under a NOS shot. I am going to be shocked if it dosnt make some good power with the STR setup.

 

Qwikcat and qwiketz, The blower is going to Stieg's for a rebuild/port. I'll let yas know how it goes on a dyno prior to an ECU tune. The TB coolant hoses will be bypassed at this juncture...unless someone taks me out of "it". qwikat, R U saying you'll soon have an ECU tune?

 

As I said I hope to have the new piggy back ecu in and running by end of June. It's not just swapping computers, it's a hard wired second ecu that must be tuned to each car and it's own set if modifactions, fuel type and paramiters. You can use a base map to start with but since it dosnt exist yet I have to build it. The new ecu has to spliced into the injs, the igntion, Tps, a new map sensor run, boost line, ect ect... Then the base tune has to be built and then modified on the dyno for hours ect... So my target date is late jun time and resorces permiting. It's only a few days to do it, it's just getting a few days free to get it done and when the dyno is avaliable.

 

Nice thread!


The AJ26 and AJ27 engines dynos I have seen can get very rich, low 10's are not unusual. However one must trust then also the O2 sensor used on the dyno.
If you have a WDS or IDS you can read the output of the upper wide band O2 sensors under open loop (so at wot), however I do not have a correct table to convert the milliamp output to actual A/F. Although I do now the ranges a bit, so at least I know in which area I am.

The AJ33/34 (so 4.2 engines) seem to be leaner and keep the timing more advance, but they also have a much quicker reacting IAT2 sensor, to which the ECU will react also much quicker contrary to the AJ26/7 ones in timing. So far the a/f rations most seem to be above 11/11.5 for stock cars.

The AJ26 engines have a higher standard timing advance of about 23 (at top rpm) , which will lower once the IAT2 temps increase. The AJ27 is somewhat lower, about 21 or so, and also there it can go as low as 16 after some power runs. As said this is a slow moving change due to the slow reacting temp sensor, the 32 bit densos are much quicker.

Until the 2005 model the ECU was a Denso 32 bit version (AJ26/7 a 16 Bit one), and from 2006 it is a Denso PanPag one. With the latter I have played a bit with a tuner, it is a very nice ECU, and one can read so much more sensors with the IDS, even individual cylinder injector timings and ignition timing/retards. This way I could perfectly see what was happening, and could give direct requests to alter specific maps. In this ECU there is also strategy to dump extra fuel at certain engine loads (at least after I had placed a twin-screw), and that could be adjusted. We used the http://www.cmdtec.it/index.asp tool to upload the maps.

I’ll bet the 32 bit denso is working not so different, thus also besides pulling timing dumping in extra fuel from certain loads/rpms.

It is still on the list of CMD to also make their tool available for the 32bit denso, but so far I think it is not yet done. A but anyone that understands the Denso ECUs, and has the tools to adjust the maps which are all located on the WDS/IDS discs, can use the IDS/WDS to upload the MAPS to the car. Of course after altering the maps on the disc, you need to change the checksum, but then of you go ;-).

Before doing new maps with piggyback systems I think it is very important to understand what the Denso ECU is actually doing under all conditions. So the car has to have run for a long time so it has had the time to learn fuel trims etc before you start measuring/tuning. So never go straight on a dyno after having the battery disconnected.

 

Was it something i said causing this thread to die down? If so, sorry for that...


Just came acrros this dyno (form you tube), of a 4.2 XJR with a 1.5 lbf upper pulley, this gives a good illustration as to what the ECU does in counteracting the heat.
YouTube - ‪Jaguar XJR Dyno Pulls‬‏

Here the dyno results:



Best power is normally in 4th gear (but in this dyno run it is in 3rd). You can see here how the heat is causing extra fuel to be squirted in (and also the timing will be retarded), result is considerable power loss in 4th. I am not endorsing anyone to advance/leaning the mixture; I see the actions from the ECU as a safety precaution. So first target should be to reduce heat imho.

 

LOL I think it had just run it's course. I have been out of town and not had a chance to pull any charts. But the one you posted is an extreme example of the same thing.

No question the heat is an issue and is causing power loss. We are in agreement it must be cured and is a must to making power with this setup. The idea is a combo of combating the iat with water inj that normally will see a 70-100 degree drop in iat's. I would expect more with the heat in the STR's case and adding boost. The next step to cool the charge with a killer chiller and hopefully up the 112s efficency at the new boost a bit with porting. As you well know the best route is a more efficent blower to start with once you have a bolt on kit I am a customer. I just do not want to go that far on my own as I have done that many times before and I don't want to take it on with this one. You know what it's like fab work, trial and error, months without the car etc...

The tuning would simply allow leaning out the overly safe factory tune. Fat is fat and lean is lean regaurdless of the reason for it. Like the dyno you posted when the stradegy is dumping tons of fuel and retarding timing to the point it pegs the chart fat that can be tweaked. That's over compensation, that car would have been just as safe if the ecu had dumped less fuel took away less timing and lower it to 11.0 rather then who knows what below 10.0.

Your not taking away the ablity of the ecu to react to a situation where detanation would occur your simply changing the fuel trims. I agree in keeping it safe, 30extra ponies is not worth cracked ring lans but there is a middle ground and having the ablity to use more octane to combat the heat and tune for it is an advantage in most circles.

 

Have no doubt that you know what you are doing, just give my views also as a customer. Not sure what sort of piggyback system you would like to use, but you need to think about the heat that the ECU is compensating (although you mention already some good measures against heat). If it is a simple ECU that can only + and - injection time at certain rpms it might be tricky as when you would set and test this based upon a hot system (so like in 4th on the graph), you could go to lean on a cold system (i.e. 2nd gear in the graph).
If you go the tuning route, and you can’t take the heat (or an extra lambda sensor to check the mixture) into consideration, then a tune on the original ECU might be the better road.

 

Yep, gotta lower the heat on the intercooler and charge coolers...Last week was 100 degrees in NY...the car was lame. Last night at 50 degrees she was and remained a beast throughout the night. Let us know what's up qwikcat. Avos, good to know you're around.

 

In sustained WOT, what approx temps do the intercoolers get to? And what does the SC radiator get to? Is there nothing to be gained between those?