My first good prom burn
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From: Medora Manitoba
My first good prom burn
HI guys,
this is my first prom burn for a Corvette 1990 Auto L98 SD with 215cc heads, "CC 12-422-8"- (Similar to Hot Cam) and stock injectors with TPI.
Can you have a look at the bin setup and let me know your opinions? I am very new to this, any help here would be appreciated
My afr is around 13.4 to 14.4 at 850 to 1200 rpm, IAC at around 90 steps at 850rpm manifold air pressure at 57 kpa. I have adjusted the Throttle blades slightly. Spark advance not adjusted yet.
this is my first prom burn for a Corvette 1990 Auto L98 SD with 215cc heads, "CC 12-422-8"- (Similar to Hot Cam) and stock injectors with TPI.
Can you have a look at the bin setup and let me know your opinions? I am very new to this, any help here would be appreciated
My afr is around 13.4 to 14.4 at 850 to 1200 rpm, IAC at around 90 steps at 850rpm manifold air pressure at 57 kpa. I have adjusted the Throttle blades slightly. Spark advance not adjusted yet.
Last edited by (vette)master; Jul 25, 2010 at 08:00 AM. Reason: Chart add
Drifting
Joined: Nov 2009
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From: Perth Western Australia
St. Jude Donor '10
Are you saying you have already put in a new chip and the datalog (ALDL) is showing you what's going on at idle?
BTW small mistake "Oxygen sensor voltage is around 1014.21 ma" should be mV (millivolts) not ma (mA - millamps).
BTW small mistake "Oxygen sensor voltage is around 1014.21 ma" should be mV (millivolts) not ma (mA - millamps).
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From: Medora Manitoba
Corrected Oxygen sensor voltage and loaded spark main table up too. I had to load this up in Tuner pro as my registered Tuner Pro RT keeps crashing in Windows 7 64 bit. The upper window is from my Notebook and is Windows Media Centre :o
Last edited by (vette)master; Jul 25, 2010 at 05:08 AM.
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From: Medora Manitoba
Drifting
Joined: Nov 2009
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From: Perth Western Australia
St. Jude Donor '10
It appears to me this is a test at idle and I presume in closed loop mode. My understanding is that in closed loop mode the computer controls the afr to 14.7 automatically. So I am not sure what your intent is here in this test as far as fuel ratios go.
Again I wouldn't think base timing at idle would be something you would expect to alter from a base tune. Shouldn't base idle be around 8 deg btdc. Wouldn't expect advance to be 22 deg at idle! Did you make it do that?
From what I have gathered a lot of the gains to be had by custom tuning are in open loop mode during acceleration or WOT. This is where the afr and spark advance would come into play to make hp gains.
The datalogger only measures sensor outputs but does not measure hp and torque. The acid test is a driving test I suppose.
Again I wouldn't think base timing at idle would be something you would expect to alter from a base tune. Shouldn't base idle be around 8 deg btdc. Wouldn't expect advance to be 22 deg at idle! Did you make it do that?
From what I have gathered a lot of the gains to be had by custom tuning are in open loop mode during acceleration or WOT. This is where the afr and spark advance would come into play to make hp gains.
The datalogger only measures sensor outputs but does not measure hp and torque. The acid test is a driving test I suppose.
Last edited by Lemme; Jul 26, 2010 at 05:14 PM.
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Joined: Nov 2008
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From: Medora Manitoba
It appears to me this is a test at idle and I presume in closed loop mode. My understanding is that in closed loop mode the computer controls the afr to 14.7 automatically. So I am not sure what your intent is here in his test as far as fuel ratios go.
Again I wouldn't think base timing at idle would be something you would expect to alter from a base tune. Shouldn't base idle be around 8 deg btdc. Wouldn't expect advance to be 22 deg at idle! Did you make it do that?
From what I have gathered a lot of the gains to be had by custom tuning are in open loop mode during acceleration or WOT. This is where the afr and spark advance would come into play to make hp gains.
The datalogger only measures sensor outputs but does not measure hp and torque. The acid test is a driving test I suppose.
Again I wouldn't think base timing at idle would be something you would expect to alter from a base tune. Shouldn't base idle be around 8 deg btdc. Wouldn't expect advance to be 22 deg at idle! Did you make it do that?
From what I have gathered a lot of the gains to be had by custom tuning are in open loop mode during acceleration or WOT. This is where the afr and spark advance would come into play to make hp gains.
The datalogger only measures sensor outputs but does not measure hp and torque. The acid test is a driving test I suppose.
Drifting
Joined: Nov 2009
Posts: 1,341
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From: Perth Western Australia
St. Jude Donor '10
My plan at this stage is to only play with the open loop settings of afr (lean it out a bit) and spark (advance more aggressively). I am mainly gearing up for drag racing.
My heads were shaved recently so the compression was increased and base timing was increased. It started to ping on first start-up. I am now running 98 octane fuel to deal with this. I note in your datalogging there seemed to be a non-zero knock count. Maybe your timing is too advanced at idle.
I note that you are running a MAP system whereas I am running a MAF system. So we are on quite different tuning paths.
Last edited by Lemme; Jul 26, 2010 at 05:18 PM.
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Le Mans Master
Joined: Aug 2000
Posts: 8,838
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From: Australia
Have to ask the question
Why 215cc heads with a TPI.
Most are only running 195's on hot 383's with a 230 /236 .575 lift cam and aftermarket intake like a Miniram or HSR
I don't see how your 218/224 .500 lift cam works with those heads notwithstanding the upper revs breathing restrictions of a TPI
Why 215cc heads with a TPI.
Most are only running 195's on hot 383's with a 230 /236 .575 lift cam and aftermarket intake like a Miniram or HSR
I don't see how your 218/224 .500 lift cam works with those heads notwithstanding the upper revs breathing restrictions of a TPI
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Have a look at the SA table for your stock ARAP bin.
20 degrees @idle no load
Exactly same as old skool carb cars where vac can on dist advanced spark under
low load ( hi vac ) situations like idle and cruise
This is why you have to disconnect ECM control of spark to set base timing; as soon as you move the dist position ,ECM will change timing to compensate if it still has control
Last edited by rodj; Jul 25, 2010 at 06:54 PM.
Drifting
Joined: Nov 2009
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From: Perth Western Australia
St. Jude Donor '10
SA shown is base plus what the ECM is adding
Have a look at the SA table for your stock ARAP bin.
20 degrees @idle no load
Exactly same as old skool carb cars where vac can on dist advanced spark under
low load ( hi vac ) situations like idle and cruise
This is why you have to disconnect ECM control of spark to set base timing; as soon as you move the dist position ,ECM will change timing to compensate if it still has control
Have a look at the SA table for your stock ARAP bin.
20 degrees @idle no load
Exactly same as old skool carb cars where vac can on dist advanced spark under
low load ( hi vac ) situations like idle and cruise
This is why you have to disconnect ECM control of spark to set base timing; as soon as you move the dist position ,ECM will change timing to compensate if it still has control
Why is the target afr 14.5 rather than 14.7? What are O2 cross counts?
Race Director
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From: Database Error Indiana
Drifting
Joined: Nov 2009
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From: Perth Western Australia
St. Jude Donor '10
What is the "block learn multiplier" and how does it work?
Race Director
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From: Database Error Indiana
The 14.5 target has been set by the programmer as the AFR he needs. Its only a target. The O2 #s constantly swing rich to lean as the ECM makes small corrections.
The BLM is the number the ECM uses to calculate fuel corrections. 128 is perfect. + or - 8 seems to the accepted number that the ECM can reliably keep the AFR at 14.7. I'm not an expert and not that good at explaining things. This is just general information. Some others here and on other forums can give detailed answers. There are some very sharp guys out there tuning .
The BLM is the number the ECM uses to calculate fuel corrections. 128 is perfect. + or - 8 seems to the accepted number that the ECM can reliably keep the AFR at 14.7. I'm not an expert and not that good at explaining things. This is just general information. Some others here and on other forums can give detailed answers. There are some very sharp guys out there tuning .
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Joined: Nov 2008
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From: Medora Manitoba
The 14.5 target has been set by the programmer as the AFR he needs. Its only a target. The O2 #s constantly swing rich to lean as the ECM makes small corrections.
The BLM is the number the ECM uses to calculate fuel corrections. 128 is perfect. + or - 8 seems to the accepted number that the ECM can reliably keep the AFR at 14.7. I'm not an expert and not that good at explaining things. This is just general information. Some others here and on other forums can give detailed answers. There are some very sharp guys out there tuning .
The BLM is the number the ECM uses to calculate fuel corrections. 128 is perfect. + or - 8 seems to the accepted number that the ECM can reliably keep the AFR at 14.7. I'm not an expert and not that good at explaining things. This is just general information. Some others here and on other forums can give detailed answers. There are some very sharp guys out there tuning .
My BLM is now fluctuating at between 122 and 128 now but its seems to be AFR 14.73 = BLM 122 and AFR 12.3 =BLM 128? richer under acceleration and BLM drops to 122. I also noticed you can change the BLM min and max?
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Joined: Nov 2008
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From: Medora Manitoba
Have to ask the question
Why 215cc heads with a TPI.
Most are only running 195's on hot 383's with a 230 /236 .575 lift cam and aftermarket intake like a Miniram or HSR
I don't see how your 218/224 .500 lift cam works with those heads notwithstanding the upper revs breathing restrictions of a TPI
Why 215cc heads with a TPI.
Most are only running 195's on hot 383's with a 230 /236 .575 lift cam and aftermarket intake like a Miniram or HSR
I don't see how your 218/224 .500 lift cam works with those heads notwithstanding the upper revs breathing restrictions of a TPI
Last edited by (vette)master; Jul 26, 2010 at 10:18 PM.
Drifting
Joined: Nov 2009
Posts: 1,341
Likes: 2
From: Perth Western Australia
St. Jude Donor '10
Have to ask the question
Why 215cc heads with a TPI.
Most are only running 195's on hot 383's with a 230 /236 .575 lift cam and aftermarket intake like a Miniram or HSR
I don't see how your 218/224 .500 lift cam works with those heads notwithstanding the upper revs breathing restrictions of a TPI
Why 215cc heads with a TPI.
Most are only running 195's on hot 383's with a 230 /236 .575 lift cam and aftermarket intake like a Miniram or HSR
I don't see how your 218/224 .500 lift cam works with those heads notwithstanding the upper revs breathing restrictions of a TPI
???cc Stock heads
195cc heads
215cc heads
The volume of the heads is getting larger here. Therefore the simple conclusion is compression is decreasing. Compression decreasing equates to less horsepower!
What am I missing here?
Drifting
Joined: Nov 2009
Posts: 1,341
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From: Perth Western Australia
St. Jude Donor '10
I just noticed that the BLM value of 112 is for cell4 (there are 16 cells across the rev range and airflow range). This is interesting because I would expect that at idle you should be sittiing in cell0. To get up into cell4 you must be sucking a lot of air into the engine and hence a lot of fuel (is this something to do with the IAC or the throttle blade adjustment you spoke about?). The value of 112 shows that the ecm has leaned out the mixture due to a rich condition at idle. See the following link:
http://j-body.net/ECM_Tuning#BLM_.26_INT
http://j-body.net/ECM_Tuning#BLM_.26_INT
Le Mans Master
Joined: Aug 2000
Posts: 8,838
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From: Australia
Combustion chamber size is completely different value
typically 54cc - 76 cc for SBC
A head of a certain intake port size is often available in different chamber sizes to allow
people to build hi or low compression ( blower ) engines
Go too big in port size on a small(ish ) engine and you have a big slug of air to get moving everytime you hit the gas =Bog .Same effect as running a 750DP Holley on a 308
Maintaining port flow velocity is one of the keys to good throttle response
Superior port design and machining lets a quality head like a AFR 195 flow more cfm than some other ( think Chinese ) 210+cc heads .That is why the flow (cfm ) figures are a better guide to head performance than the port size alone
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From: Medora Manitoba
