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 Post subject: Wide Band Lambda
PostPosted: Wed Aug 31, 2005 9:42 pm 
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Location: Perth, Western Australia
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Well, the masked highway robbers from Oz (MoTeC) have drained my bank account again :( ...... turned out I didn't have the 'full' Pro option enabled on my M4. When I had the memory expansion fitted last year I was sure that was the full Pro setup but it turns out it was just a memory upgrade.

Owens were pretty decent and only charged me for two hours despite the fact they worked on it for longer to replace a broken stud on the O2 sensor housing.

Stormy Blue also sailed through her new MOT. Its one of these new fangled computerised versions where its all connected to VOSA by modem and once they are happy with the data THEY authorise the printout remotely in the MOT garage :shock: I'm just glad they don't have a webcam to see what really went on :wink:

Anyway, had a good chat with Mark about the coolant boiling issues, sensor locations, logging and mapping so will report on that separately.

The Overrun fuel cut has now been enabled above 1800rpm as well as the lambda closed loop control. I don't know whether its my imagination but it seems to have made a difference already with the engine running smoother and economy improving. To be fair I need to give it a couple of weeks of varied running to really see the difference.

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PostPosted: Thu Sep 01, 2005 12:02 pm 
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Do you now have the wideband permanently fitted then?

If so, what's the predicted lifetime. I know the Bosch LSU4 (standard Honda and VW fitment) in my kit is specified as a 500 hour lifed item


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PostPosted: Thu Sep 01, 2005 12:39 pm 
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Mark said my Bosch sensor is lifed at 500 hours. The sensor itself cost £145 which I didn't think was too bad. Apparently Toyota need the more expensive three wire sensors the cheaper five wire type aren't compatible :(

At least now there is nothing more I need to do ECU wise :) Interestingly, Mark said most professional tuners do not like integrated knock/retard capability due mainly to the unpredicatability of the 'noise' coming from the knock sensor. Its fine to monitor via an HKS gauge like Fennies do and/or use det cans but in his view its the SAFE MAPPING that is the key to keeping your engine in one piece.

Owens had a very experienced mapper over from the States recently and he doesn't use any of the integrated knock/retard capability found in some ECU's

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PostPosted: Thu Sep 01, 2005 6:05 pm 
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interesting stuff Don. I guess they use the stock wiring for the o2 sensor? in which case there are only 4 wires from ecu to o2 sensor hence the need for the 3 wire. I really cant think of any other reason why Toyota require a 3 wire rather than 5 wire, open to comments.

I can see where they are coming from with the knock feedback. The ECU does not have satisfactory signal processing capabilities to get a predictable knock signal. Essentially I think that the knock sensor just gives a voltage swing output depending on the amount of noise it is subjected to from engine vibration. Remember though that they are piezo transducers that are tuned to a specific frequency though. In my experience with noise and vibration monitoring the human ear is a far more effective test transducer and signal processor than commercially available (and its free!) You just need to know how to use it and where to put it.

I can only assume that Owens use det cans to establish their SAFE MAP though, you can have a stab at a safe map without them but it would be very safe and not very powerful.

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 Post subject:
PostPosted: Thu Sep 01, 2005 9:01 pm 
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Its a shame you can't watch them do the RR mapping now because of all the H&S regs (sorry Mike :wink: ) but I'm sure they do use some kind of method to monitor det.

When we did some road adjustments last year it was all done using the large MoTeC digital AFR gauge but of course this was all at low engine speeds and off-boost.

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PostPosted: Thu Sep 01, 2005 10:22 pm 
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Don - the thing thats frustrating is there's no reason why you can't be allowed to watch, unfortunatly for most companies its easier to just have a blanket ban on this sort of thing rather than putting some thought and money into it.

Also the question is more one of liability rather than H&S, they are afraid members of the public will take legal action if theres an accident. In reality they should be just as worried about there employees sueing aswell.

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 Post subject:
PostPosted: Thu Sep 01, 2005 10:45 pm 
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I'm sure you're right. Its a lot easier for them to say no and it keeps the pesky customers out of their hair too!

I got a lot of useful info from Mark yesterday. He had a look at the log from the Silverstone evening when my rad 'went critical'. There was nothing obviously amiss although he says sometimes a split block or partially failed head gasket can cause this sort of symptom under high boost. i.e. this can effectively 'pressurize' the coolant. He tested the coolant for traces of hydrocarbons and it passed with a a clean bill of health. Looks like the swirl pot and expansion tank will be the next mod but its still a case of suck it and see R&D :mrgreen:

As a matter of interest he has found he can lower the temps on his racing Honda Civic Type R by about 10 to 15 deg C simply by ducting the air through the rad properly.

I recall noticing this same attention to cooling detail on Seb Loeb's Citroen Xsara WRC during the last rally in Germany. The mechanics had pulled the nose section off to reveal what can only be described as Kevlar sculpture ducting air to the rads and the brake cooling ducts etc. The air was not given a choice of where to go :!:

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1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
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 Post subject:
PostPosted: Sun Sep 04, 2005 9:38 pm 
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Don - good news on the wideband.

iirc the Haltech gurus recommend having the fuel deceleration cut rpm point at somewhere around 1500rpm.

The WRC 185 has this sculpting in the nose cone that you refer to Don.

JP - I stuck a knock sensor output on a scope a while back and I was a little surprised at the output. The output from the sensor is very messy indeed iirc the "signal" was floating around 2V, (will have to check). I would suspect however that there would be a pronounced increase in the amplitude once det began to occur.

As I mentioned before I have a prototype det monitor that I plan on running extensively on my new engine. The "blind" section next to the original KS position is going to be drilled and tapped to accept an additinal KS, which I hope to use as a tuning aid.

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 Post subject:
PostPosted: Mon Sep 05, 2005 12:31 am 
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Kris, off the top of my head I think Mark said he'd set my decelleration fuel cut limit at 1800rpm.....pretty close to the figure you mention.

Sounds like you're planning on mapping your new engine 'on det' :shock:

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 Post subject:
PostPosted: Mon Sep 05, 2005 8:18 am 
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Don, from what I understand the typical practice for mapping the timing is to advance it in each load cell until teh onset of det (just audible with det cans) and then backing off the timing a couple of degrees and checking that no det occurs under any circumstance. Turbo cars seem to produce most power/torque the more timing you advance in. This is only limited by the onset of det. retarding the timing will start to increase the EGT's and det will injcrease EGT's so y0ou can use the egt gauge as another form of locating good timing. (whilst it is a guide det is a far more serious issue and is used for the primary indicator) You have to bear in mind that you and I are running circa 10 deg BTDC at high boost and load. Turbo cars also spread the cylinder pressure out over a longer period than NA cars so more "power" to be extracted is likely to remain if teh timing is too far retarded (mild anti lag?)

The good thing about the HKS knock monitor that Fensport use is that it gives a bar graph style knock indicator BUT you can plug your headphones in too and listen to it.

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 Post subject:
PostPosted: Mon Sep 05, 2005 12:50 pm 
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Interesting.....I hadn't realised that mapping a (turbo?) engine was so close to the edge in terms of detonation. I assumed it could be mapped to give good power without getting close to det under 'normal' conditions.

There was an interesting comment in Autosport this week from Pat Symonds, the Renault F1 team manager. He said that both Alonso's and Fisi's engines detonated during one of the really hot races earlier this year. Alonso was lucky :mrgreen: and survived the race and even won the next race the following weekend with the same engine. Fisi, as usual, was less fortunate :cry:

You may recall that the eagle-eyed Mr. Kelly spied an ERL WI pump mounted on the sidepod of the R24 at Goodwood FOS. The Renault engineers claimed this was just for the FOS but in the light of Pat Symonds comments I'm wondering if its not a more permanent fixture. Mike thought the use of WI was illegal under current F1 regs but I'm not familiar enough with the regs. I do know that the use of WI will be banned under revised WRC regs for 2006. It will be interesting to see how the teams cope with high plenum temps next year. Maybe we'll see some sort of heat exchanger system such as the RX-7 boys use?

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1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp


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 Post subject:
PostPosted: Mon Sep 05, 2005 5:06 pm 
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JP - didn't realise that the HKS kit came with a meter aswell :shock:

Don - at present I don't plan on mapping the thing on permanent det!

The fuelling is pretty straighforward, look at a meter and read off. The ignition timing is a bit more awkward. I would like a meter to tell me "STOP", whilst I am making my mind up on the det cans whether that's det or not :lol: i.e. I would use it as a backup just in case I missed it.

Unfortunately hearing and appreciating det and it's various guises I think can only be done when you hear it...and you want to be hearing it as little as possible! :shock: this makes for learning out det a bit awkward since you don't want to hear it.

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 Post subject:
PostPosted: Mon Sep 05, 2005 6:46 pm 
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Let me understand this then ..... even if you run a slightly rich mixture as evidenced by the wide band lambda if you then advance the timing you are likely to get det? I always understood in NA engines all that happens is you lose power. Is it different in turbo engines where the combustion chamber is hot enough to cause pre-ignition?

I think I need to consult my various tuning bibles when I get home tonight :lol:

In the meantime feel free to keep educating me :wink:

PS Mike, we need one of these :bow down: or :worship: smilies in the emoticons list when I reply to JP and Kris :)

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Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp


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 Post subject:
PostPosted: Mon Sep 05, 2005 7:25 pm 
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Don - yep, this is my understanding. Even if you run say 10:1 AFR, if your ignition timing is too far advanced then you will get det.

I believe det is helped to be kept at bay by running richer mixtures but there is only so much that the cooling effects and slow burn effect of a rich mixture will help?

For what it's worth I think an AFR of 14.7:1 at idle/ steady rpm, (not much load), is fine. As the turbo begins to spool up then run an AFR of ~12.5:1 which gradually richens up until ~11.5:1 when the turbo is on full song, (maybe a touch richer).

Extracting extra power I believe is in running these sorts of AFRs and then advancing the ignition timing until ~3degrees from the onset of det.

The next trick is now that the engine is mapped is to ensure it runs correctly and safely under all circumstances i.e. cold winters night, hot sunny day, high water temps, low water temps, high electrical loading etc.

The more I think of it and the more JP shows me the Power FC, the better this bit of kit looks! :D Whilst it doesn't appear to do anything once the "det" threshold is reached, (user definable), it does activate the stock engine warning lamp to indicate a problem - personally I really like this feature, as it monitors "stuff" and alerts you to a foul up!

JP - are you preparing a powerpoint presentation on the PFC and Datalogit? ;)

All the above is my 2p, right or wrong! :)

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95 ST205 - slept for 10 years, now waking up...
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Turbocharging - the replacement for displacement


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 Post subject:
PostPosted: Mon Sep 05, 2005 9:07 pm 
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Kris, I will prepare a power point presentation on them once I have sorted the web site stuff. Oh and turbos, intercoolers etc. I hope you will return the favour with your Cadbury's Caramel how to's :-)

Don, indeed turbo and NA cars are totally different in the way that you map them. A NA car can only really be set up on teh dyno, with accelerometers on teh road to detact the power you are getting at a given load cell. Turbo cars are far more predictable once they come onto boost it is all about cylinder pressures and the rate of burn with a turbo car. Hence my reasoning that the dreaded WI actually slows the burn and loses torque/power. You need cooling that is predictable and you can map to or dont bother IMHO (especially on a custom built engine for your desired boost/rpm). The only time that WI is usefull is as a band aid for running high boost on a stock engine without other intercooling efficiency increases. (Jp waits for flaming )

If you are running a rich mixture all it does is slow the burn rate of the mixture (the additional wasted fuel just cools the cylinder/piston etc) This does mean you can run a little more timing advance typically. Getting the balance is the difficult bit. If you continue to advance the tinming you WILLL get det. The higher the pressure the quicker teh burn rate, the higher the pressure the higher the temp of the mixture prior to it being ignited.

From what I have read max power from a turbo car is circa 12.4-12.8/1. From a reasonable source the 3SGTE likes 12.6:1 for max power. The difficulty is that because of teh time scales invloved you really need to run a gear trim for fuelling, (yes the motec has teh facility- no yours is activated) in say 5th gear the car will run leaner than in 1st. This is not a massive amount but if you are trying to extract every last bhp out of it you can use it to your advantage. Most others just run a slightly "safer " mixture (rich). Personally I woudl like to aim for 12:1 on a 4th gear run (as long as knock is permitting at the level of boost I run. I would also like (have designed a map for) a safety feature on my map where if it overboosts it gets rich and the timing is retarded.

There are alos a few bits you can play with to get teh turbo to spool better at the expense of something! Either retard the timing and richen teh mixture (small antilag effect) or a weak mixture and advance the timing to get the most power from teh engine (highish egt's) and hence the most exhaust gases.

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