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Alan L's Avatar
 
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I should mention, that sadly, the flames have gone from the exhaust on over-run.
I put this down to faulty timing in the vacuum phase, initially.
Alan
Old 08-03-2008, 03:13 PM
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That's great news!

Could you give us the run down on your AFR's vs. RPM at ful throttle? Can you hook up your WBO2 so it logs those two things?

I used my LM1 + LMA3 to log those things. It's really usable in order to troubleshoot the fueling.

Here is a snapshot from my Audi:



As you can see, somewhat leanish AFR is OK before the boost kicks in (as long as it's richer than 14.7)
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Last edited by beepbeep; 08-03-2008 at 04:19 PM..
Old 08-03-2008, 04:14 PM
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Goran, with my current fuel settings, when the WUR boost diaphragm kicks in, my AFr's drop into the 9s. The car bogs. It did not do this intially with my previous fiddling. But when I got the car, the system pressure was pegged, at a guess somewhere around 120-130 psi, and my WUR cold pressure was 50 psi. I lowered these to book values, and about that time had my AFR in. Last track date, with my suspect dizzy, my AFRs on boost would drop to 11.5 and rise to 12.2 at redline (6000) - which from all I have heard on this board is about normal - running out of fuel at top end. But my pre boost AFRs were quite lean - low throttle in the 14-15s and the car just bogged down completely. Would not tolerate it. So I have assumed all along that the fuel management has been the problem. Certainly getting the pre boost AFRs down has improved it. But then the top end was too rich.
I then found my WUR pressures were still suspect because my battery may not have been good enough. Put new battery in and found they were still high by book values, and dropped them to book spec. I have dropped my WUR cold and system pressures by about 30 psi from when I got the car. But now my boost enrich is far too heavy. Strangely, in desperation for the track day, I tried blocking the boost dump off, and found it behaved like you would programme a digi WUR - it got richer with revs at top end. I expected it to lean off.
I can't log this data simultaneously at the moment, but I do have an analogue output on my AFR. At the moment I watch it, which can get a bit busy in traffic. Every now and then you find a clear bit of track, and monitor it. It is sitting just above top of my steering wheel - the one piece of data I can see all the time. Basically at moment low throttle pre boost it is around 14, as it hits boost it progressively drops (rather than dumps) and richens thru the 12s into mid 11's at max revs. I can change this end point (and fiddled with it at the track) - but it has the same effect at the other end of the range. If I try and put more fuel in for the pre boost lean spot, I get a richer AFR at top end.
This behaviour is very strange from all I've heard. I can feel a slight flat spot at the boost transition (which may be knocking some of the edge off the boost onset) , and suspect it would like a quick dump of fuel to get up and go at this point. I was considering getting some heavier WUR boost springs made up. But think I'm probably better to go with the digi WUR. I wonder with the previous unusual fuel set up if the WUR spring has been changed to match the fuel managment that was set up - which was definitely all out - dump as much as you can.
One Porsche tech at the track y/day suggested it may have come with a RUF fuel set up - given it has RUF wheels and front/rear ends, plus some engine mods.
After months of flat spots pre- boost it just feels so different to have progressive throttle response. Different car. And great fun to drive now. Just have to get it going faster - still behind my previous NA lap times.
Regards
Alan
Old 08-03-2008, 04:50 PM
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Quote:
Originally Posted by beepbeep View Post
That's great news!

Could you give us the run down on your AFR's vs. RPM at ful throttle? Can you hook up your WBO2 so it logs those two things?

As you can see, somewhat leanish AFR is OK before the boost kicks in (as long as it's richer than 14.7)
I'm not a techno person on the computer/electronic stuff - can find broken wires, measure resistance etc - but thats about it. But we are trialling some very small cameras (size of an egg) on karts, considering making it mandatory for each kart to carry one. To resolve race incidents. They take a small memory card and record up to 2 hrs of info in digital form, then overwrite the original stuff - continuous. You pull the card out, plug in laptop and high quality pictures/sound emerge. You can slow- mo, freeze frame. The quality is so good you would think you were in the seat. No vibration, blurring, whatever. So am looking at installing one to monitor the gauges. Cost about $200. Probably cheaper than setting up datalogging, and can use in car later.
You can see from your data that there is a quick AFR boost dump - which I suspect they want. With my WUR boost port disconnected, I am not getting this, but somewhat unexpectedly, get a progressive lowering of AFR. So at the point yours drops from say 14.5 to 12? mine would would go 14.4, 14.3, 14.2..... until at max revs we hit 12. But if I hook the boost dump in at moment I would go 13.5 - 9.5 and stay there.
Trying to order digi WUR at moment. Once they discover where NZ is, we will be in business. The site won't let me order at moment - because it has not heard of NZ, and I'm not allowed to tell it. Columbus found America a few hundred years ago, but techno Unwired has yet to find NZ.
Regards
Alan
Old 08-04-2008, 12:52 PM
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Alan, I suggest you send Steve at Unwired an email.. I'm sure he'll take your money!!
Todd
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Old 08-04-2008, 02:43 PM
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I have e mailed them
Waiting to hear back.
Alan
Old 08-04-2008, 04:33 PM
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I too thought about recording my rev counter, boost gauge and AFR all at the same time...
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1981 UK 930. G50/01 shortened, 964 3.8RS Fibreglass Body Kit, 18" Alloys 8.5" F & 10" R, 225's F & 285's R, Special Colour Metallic Blue Paint, FIA Sparco Evo's, A/C and Air Pump removed, Electronic Boost Controller, GHL Headers, Tial46 WG.
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Old 08-05-2008, 12:35 PM
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You have an electronic boost output from the tacho gauge, plus the AFR and tach are electronic, so an electronic techno could probably hook these up to a data logger no problem.
I just figured this may be simpler - for me at least. Camera on its way. I will install it permanent in the car when finished with data logging.
Figure I can freeze frame my way thru all the data points.
Alan
Old 08-05-2008, 12:52 PM
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Quote:
Originally Posted by Alan L View Post
I'm not a techno person on the computer/electronic stuff - can find broken wires, measure resistance etc - but thats about it. But we are trialling some very small cameras (size of an egg) on karts, considering making it mandatory for each kart to carry one. To resolve race incidents. They take a small memory card and record up to 2 hrs of info in digital form, then overwrite the original stuff - continuous. You pull the card out, plug in laptop and high quality pictures/sound emerge. You can slow- mo, freeze frame. The quality is so good you would think you were in the seat. No vibration, blurring, whatever. So am looking at installing one to monitor the gauges. Cost about $200. Probably cheaper than setting up datalogging, and can use in car later.
You can see from your data that there is a quick AFR boost dump - which I suspect they want. With my WUR boost port disconnected, I am not getting this, but somewhat unexpectedly, get a progressive lowering of AFR. So at the point yours drops from say 14.5 to 12? mine would would go 14.4, 14.3, 14.2..... until at max revs we hit 12. But if I hook the boost dump in at moment I would go 13.5 - 9.5 and stay there.
Trying to order digi WUR at moment. Once they discover where NZ is, we will be in business. The site won't let me order at moment - because it has not heard of NZ, and I'm not allowed to tell it. Columbus found America a few hundred years ago, but techno Unwired has yet to find NZ.
Regards
Alan
Hello Alan!

If I understand you correclty, your pre-boost AFR's are roughly OK (~14.4) but problem is that they don't go down to 12's when boost comes? And if you connect boost compensation hose to WUR, they get too rich, correct?

Well that's easy thing to solve:
Just lower the pressure in WUR boost port until you got AFR's in 12:s at boost. Its just amatter of fitting a controllable leak. I suggest following:

Connect boost hose to WUR trough a plastic T-piece. Let one side go to WUR and another to your filter box (or add one-way valve to it). This will make pressure going to WUR drop to 0.3 bar or so (depends on hose diameter, use small diameter hose so you don't have to bleed lot's of air or you idle will go up).

Then just fiddle with amount of bleed until pressure going into WUR is just right to keep AFR's in 12:s. If you are lucky, you won't need digital WUR at all

Regards,
Goran
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Old 08-05-2008, 01:43 PM
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Very clever Goran - that would fix it. I am in the process of ordering a digi WUR - but will keep that in mind. I was going to fiddle with the spring pressures in the WUR.
But decided a digi WUR would give much more precise control over the whole range. I still think the AFR is leaning out a bit much pre boost. 14 may be good for economy and normal throttle response, but for track stuff, I suspect it needs to be a bit lower. The car feels much more throttle responsive around 13. So the AFR ranges seem difficult to achieve with the conventional set up. A digi WUR would solve all that in one go. But I wish I had thought of your suggestion before last track day - would have used it.
Regards
Alan
Old 08-05-2008, 03:12 PM
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Hmm, I don't see any problem with running AFR of 14 pre-boost. Your engine has very low compression ratio and knock risk pre-boost is minimal. Too much fuel cools the exhaust gases (which is OK on boost, in order to avoid the knock). But turbo actually lives of temperature difference before/after and the hotter the better.

I don't know what digi-WUR costs but I believe it would be worth trying the nipple trick.
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Old 08-05-2008, 03:35 PM
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Thanks Goran. Just that the car feels more responsive with AFR below 14 pre boost - throttle feels more positive.
With earlier fuel pressures (set to 'standard' - but with battery not up to spec) I had pre boost AFrs of 14 -15 and my boost AFR was down to 11.5 and climb to 12.2 @ max revs. If it had not performed so badly in the pre boost range, it would have been OK. I wish I had discovered the dizzy problem then.
I since reset the fuel pressures to standard with new battery - this meant dropping them further. Now my pre boost AFR is 13-14, car responds much better (dizzy fixed), but boost dumps heaps of fuel.
Amazing what difference to the fuel management the pressures make. They seem to completely reconfigure the system. I could always put another 10-15 psi back into the fuel system (WUR and System) and see what happens - but not that happy with AFR 14.5. May be that I have just had such a frustratingly long experience with it behaving badly with this characteristic.
Digi WUR $US700. About same as set of injectors.
Regards
Alan
Old 08-05-2008, 04:15 PM
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Quote:
Originally Posted by beepbeep View Post
Hmm, I don't see any problem with running AFR of 14 pre-boost. Your engine has very low compression ratio and knock risk pre-boost is minimal. Too much fuel cools the exhaust gases (which is OK on boost, in order to avoid the knock). But turbo actually lives of temperature difference before/after and the hotter the better.

I don't know what digi-WUR costs but I believe it would be worth trying the nipple trick.
Actually I"ve discussed this at length with Steve at Unwired tools and I'm running around 14-15 at a narrow band around 2000-2250 rpm under 1.2 bar ( 0.2 boost), this is my "economy mode) for the 4 hr drive to the track.. I always have a laptop and have the serial port running to my front seat.. When I get there I just dial in the "track map" .. As long as you're not hearing any knock you're good to go!!
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Old 08-05-2008, 04:22 PM
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Actually I"ve discussed this at length with Steve at Unwired tools and I'm running around 14-15 at a narrow band around 2000-2250 rpm under 1.2 bar ( 0.2 boost), this is my "economy mode) for the 4 hr drive to the track.. I always have a laptop and have the serial port running to my front seat.. When I get there I just dial in the "track map" .. As long as you're not hearing any knock you're good to go!!
Does this mean you find more response by running a lower AFR in this rev range?
What is the reason for dialling more fuel in?
Regards
Alan
Old 08-05-2008, 04:39 PM
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No you mis-understand I'm running higher AFR for fuel economy.. I think it would be a little more responsive running a bit richer..
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Old 08-05-2008, 05:34 PM
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I figured that was what you were attempting. You have leaned it off to AFR 14- 15 for hway cruising - and I guess that is your rev range in that mode. But for the track you have a lower AFR programme for that rev range - based on the fact you believe you get better throttle response.
Did you set the track programme by dyno? I believe I am getting better throttle in the 2-3000 rpm range by running AFR under 14 (not worried about mpg) - but I am only going by the feel of the car. Seems to want to pull more instantly and harder - ie depress throttle and it responds immediately, rather than being a bit sluggish to pick up.
Alan
Old 08-05-2008, 05:46 PM
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No I don't have a dyno, in fact until I get the LM-2 so it can read rpms ( seems to be a conflict with the signal going to both digital wur and the LM-2 but it will be fixed next weekend I think). Then I can make some runs , don't think I'll really need a dyno..
But yes to answer your question, it is fairly sluggish when it's that lean .
T
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Old 08-05-2008, 06:09 PM
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Quote:
Originally Posted by beepbeep View Post
Connect boost hose to WUR trough a plastic T-piece. Let one side go to WUR and another to your filter box (or add one-way valve to it). This will make pressure going to WUR drop to 0.3 bar or so (depends on hose diameter, use small diameter hose so you don't have to bleed lot's of air or you idle will go up).
Regards,
Goran

Thinking about this, Goran, are you sure it would work? I guess you have done it and know it will. But in theory, I would have thought you would have equalised pressure thru whole boost system. For instance, if your gauge reads 0.8 bar, you have same pressure everywhere thru your intake system after the turbo. So, 0.8 bar also arrives at Tee piece on WUR. You bleed a small amount off to loss, but you still have 0.8 bar in the system, so the remaining going into WUR is still at 0.8 bar? If you had a very narrow constriction into the WUR, maybe there is a small delay, but eventually it will still equalise with boost pressure?
Incidentally, I have found why the boost/vac port only works one way (boost). The chamber is actually closed off to the rest of the system and the diaphragm rests hard up on the base of the upper springs mounting - on top of the boost spring, ie under vacuum, it can't extend any further up to increase CP. It can only go down, under boost pressure to reduce CP. So, in mechanical WUR, CP is constant, except under boost.
Alan
Old 08-05-2008, 08:42 PM
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Quote:
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Thinking about this, Goran, are you sure it would work? I guess you have done it and know it will. But in theory, I would have thought you would have equalised pressure thru whole boost system. For instance, if your gauge reads 0.8 bar, you have same pressure everywhere thru your intake system after the turbo. So, 0.8 bar also arrives at Tee piece on WUR. You bleed a small amount off to loss, but you still have 0.8 bar in the system, so the remaining going into WUR is still at 0.8 bar? If you had a very narrow constriction into the WUR, maybe there is a small delay, but eventually it will still equalise with boost pressure?
Yes, I'm quite sure this works. T-ing a boost signal line has been used forever to raise boost by venting a portion of air going to the wastegate. This is also how usual pneumatic pressure controller works.

It's the ratio between bleed diameter and hose diameter that is determining the pressure loss. If you have a pressure gauge you can try this on your bench. Connect a T-piece to shop compressor regulated down to 0.8 bar and connect pressure gauge to another part of T. Then you can lab with orifice diameter on third nipple of the T until pressure felt by pressure gauge is whatever you would like it to be. I would adjust it to 0.3 bar and then do a test run.

Regards,
Goran


P.S. WUR is working on the same principle. Only difference is that it uses fluid instead of air. WUR "bleeds" certain amount of fuel and thus lowers the control pressure. If you can shape boost pressure entering the WUR, you can also shape the fueling on boost to reasonable degree. You can do it in many ways: by changing the WUR spring force (which you mentioned), by decreasing the control pressure trough Mercedes BTR (which is in place?) or by manipulating the boost signal to WUR (which I suggest).
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Last edited by beepbeep; 08-06-2008 at 01:46 AM..
Old 08-06-2008, 01:41 AM
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Alan, you may find you are getting better response with a richer setting not only due to AFR but also that the metering plate will lift easier and not be throttling the engine.

As for bleeding off to reduce pressure at the WUR. Placing a restriction before the tee may help and then controlling the leak at the centre branch of the tee will reduce pressure on the final branch of the tee piece. Also, you won't waste so much air and this will help not to alter other things. Without a restriction you will have to waste a lot of air to get a pressure drop which is what I believe you were thinking Alan.
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1981 UK 930. G50/01 shortened, 964 3.8RS Fibreglass Body Kit, 18" Alloys 8.5" F & 10" R, 225's F & 285's R, Special Colour Metallic Blue Paint, FIA Sparco Evo's, A/C and Air Pump removed, Electronic Boost Controller, GHL Headers, Tial46 WG.
Fitting - New service kit.
Needs Fitting - Innovate XD-16 Kit, Kokeln IC. Stephen's K27 HFS, EVO Intake Assy & his Modded USA Fuel Head.

1983 UK 911 3.2 Carrera Sport Coupe. Black, Black Leather with Red Piping, Black Alloy Gear Knob, K&N Air Filter Element, Turbo Tie rods.
Needs Fitting - K&N CO Sensor, Round A/F Dial Gauge, Factory Short Shift Kit.

http://www.danasoft.com/sig/Iamnotanumber.jpg
Old 08-06-2008, 11:16 AM
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