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  #46  
Old 11-21-2007, 10:07 AM
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Quote:
Originally Posted by svxistentialist View Post
Hi Phil

No trouble asking, but I don't actually know. Graham fitted the gear before I traveled over.

If I was to guess I imagine it is using its own JDM ecu. I'll chat to Graham and check it out.

Joe
The reason I ask is that Graham's UK ECU and your JDM ecu have different knock correction maps. So moving the installation from one car to another is not necessarily the "proof of the pudding".
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  #47  
Old 11-21-2007, 11:58 AM
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Good point Phil.

I think that only muddies the water, it does not disprove the point. I say this because I expect the differences in the knock control maps to relate to petrol quality.

These differences between markets are likely to be of an order of magnitude that is several scales below the difference between the ignition being pulled completely and totally back and minor adjustment for 91 octane average vs 94 octane average petrol quality.

BTW it is running on its own jdm ecu. It would not run with Graham's one.

Joe
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  #48  
Old 11-21-2007, 01:09 PM
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I was thinking of comparing two USA car one NA & one with the super charger. I have an idea that I will put up on the forum tonight when I get some bits that should make it easy to do the testing.
I will post on the ECU thread a comment about Air/Fuel as we need to look at that as well.
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  #49  
Old 11-22-2007, 03:10 AM
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Its worth reading this artical about knock sensors.
http://www.autospeed.com/cms/article.html?&A=0348

Tony
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1995 - SVX 700,000 K Mine, DMS Struts to lift car 2in. Tyres Wrangler Silent Armor 235/70R16, PBR Radiator. 6 speed with DCCD and R180 rer diff, Heavy duty top strut mounts front and rear. Speedo correction box fitted. New stero (gave up on the old one). Back seat removed and 2 spare tyres fitted for desert driving. ECUTune SC sitting in the box for the next SVX.
1992 - SVX 255 K Wife (Want to stay Married so not allowed to fit SC)
1992 - SVX Pearl with black roof race car roll cauge etc ready to race. Ex Tasman Targa car.
1995 - SVX Green low k mint condiation.
1995 - SVX Rally car, ex Matts car. Now to be used on track.
1992 - SVX red & Black being converted to Mid Engine.
1995 - SVX Red 143,000 bit rough.
Owned 5 others Subaru back to a 1974 1400 GSR.
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  #50  
Old 11-22-2007, 04:19 AM
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Quote:
Originally Posted by Dessertrunner View Post
Its worth reading this artical about knock sensors.
http://www.autospeed.com/cms/article.html?&A=0348

Tony
Thanks Tony

That device on Part 2 is very similar in principle to what Trevor was advocating.

Reading Part 1, it appears to me that the discriminating circuits to decide what signals are actually detonation, these must be programmed into the ECU.

And then if this is the case, in adding a blower to the cylinder block matrix, we are actually adding an additional noise source into the equation. This additional noise will not have been accounted for or compensated for by the engineers designing the knock detection circuits and sensor placement. If nothing else, this must increase background noise and increase the signal amplitude and possibly change or adulterate the frequency of the signal as read by the discriminator circuit.

The worst case scenario is that some of the noise generated by the blower will be comparable in amplitude and frequency to the noise generated by detonation. In which case the circuitry will retard the ignition to safeguard the engine.

It's hard to see where we could go from here with PD blowers. The only simple solution I can imagine for the present would be to drill the bottom of the block and site the two sensors underneath and away from the side that the blower is bolted to.

Joe
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  #51  
Old 11-22-2007, 01:09 PM
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I have been trying to find a way to simply read the ignition timing but haven't found it. My logic is if we can see the timing number then we can see if the knock sensor is effecting the timing or not very clearly.
- One question I don't know the answer to is what if we put in a resister to pull the signal reading lower then it really is, may be a stupid idea.
- Just thought of a different option there is a kit aviable that will adjust the output voltage of different sensors. That would work because you could remap the signal.
Tony
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1995 - SVX 700,000 K Mine, DMS Struts to lift car 2in. Tyres Wrangler Silent Armor 235/70R16, PBR Radiator. 6 speed with DCCD and R180 rer diff, Heavy duty top strut mounts front and rear. Speedo correction box fitted. New stero (gave up on the old one). Back seat removed and 2 spare tyres fitted for desert driving. ECUTune SC sitting in the box for the next SVX.
1992 - SVX 255 K Wife (Want to stay Married so not allowed to fit SC)
1992 - SVX Pearl with black roof race car roll cauge etc ready to race. Ex Tasman Targa car.
1995 - SVX Green low k mint condiation.
1995 - SVX Rally car, ex Matts car. Now to be used on track.
1992 - SVX red & Black being converted to Mid Engine.
1995 - SVX Red 143,000 bit rough.
Owned 5 others Subaru back to a 1974 1400 GSR.
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  #52  
Old 11-22-2007, 08:38 PM
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Quote:
Originally Posted by sicksubie View Post
OT tried that and had zero results
what do you mean by zero results?
-Bill
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