steveespo
@21CarProductions @NJS58 Racing @NJS58 Eurosport
What is the total timing in the tune? Assuming 93 octane, but are you running 91?
Sorry I haven't read every post for the specs
Sorry I haven't read every post for the specs
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- Thread starterBackInBlack
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Chassis Swapped Boss 302
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- Thread starter
- #182
93 octane, stock tune. Usually get 3 degrees knock at wot. No problems with regular street driving
- Thread starter
- #183
By process of deduction, it seemed that my only remaining culprit was something to do with the engine. Either my cylinder scoring or maybe problems with the valve seals. Even though I am not willing to replace the short block or cylinder heads over this, I wanted to verify the findings. I did a series of WOT pulls using the different configurations I have available. Here are 3 results using the following configurations: SCT 93 octane tune + 93 octane, SCT 91 octane tune + 93 octane, and SCT 91 octane tune + 93 octane + Lucas octane booster.
I don't have any proper tunes, so I used what I have at hand. The 93 octane tune is a little more aggressive than the stock tune. They both produced 3 degrees of knock, but the SCT 93 tune sustained that knock for a second longer. Using the SCT 91 tune reduced my knock down to 2 degrees, and adding octane booster eliminated my knock!
At first, I thought that this confirmed a minor engine issue, but I went over this with AI, and the AI says that this is incorrect, and that these logs prove that my engine is working as it is supposed to! The AI says, that if this problem were being caused by an internal issue, that the knock would not be affected by an increase in octane (I would think that this would depend on what the internal issue is...). Which I guess would make it indistinguishable from false knock? The AI says that my most likely culprit is bad gas. I don't like this theory, because I've already tried using gas from several different places and get no change in results. Considering the things I've already done to diagnose, a valve seal problem seems less likely at this point. I never see any blue smoke, and my oil consumption is relatively normal except under sustained (road trip) highway driving. So if oil is getting into my combustion chamber, it seems that it only happens under certain conditions. It also seems less likely that it's blowby. I'd think that if it were blowby that my knock would continue up to 7500 RPM and it never does.
I thought about this, and came up with a new theory. Fortunately, this one won't be hard to test. A while back, I noticed that the inside of my intake manifold was caked with oil and so I installed an FRPP oil separator. This seems to be doing a good job, but I've learned that under WOT, the airflow in the crankcase reverses because there is no vacuum to open the PCV valve. In this case, blowby gasses are expelled via the crankcase breather hose. I would imagine that when the airflow switches directions like this that there is momentarily greater pressure inside the crankcase than normal. What if, when the airflow switches direction, a slight buildup of pressure is pushing a puff of crap into my intake? If this was the case, it would explain why my knock always occurs at about the same RPM in my logs, and why it tends to step down and go away after an initial spike, even though the car is still building RPM. If this is the case, all I need is a simple driver's side catch can!
I went ahead and ordered a kit from Radium and am looking forward to some more tests. For the time being, the 91 SCT tune seems like it's the safest so I left that on the car. Let me know if any of you guys disagree with any of the thinking here. I'm no mechanic! Just doing the best I can.
One thing that I think that I can rule out completely though, is false knock. So my noisy transmission is good to go!
I don't have any proper tunes, so I used what I have at hand. The 93 octane tune is a little more aggressive than the stock tune. They both produced 3 degrees of knock, but the SCT 93 tune sustained that knock for a second longer. Using the SCT 91 tune reduced my knock down to 2 degrees, and adding octane booster eliminated my knock!
At first, I thought that this confirmed a minor engine issue, but I went over this with AI, and the AI says that this is incorrect, and that these logs prove that my engine is working as it is supposed to! The AI says, that if this problem were being caused by an internal issue, that the knock would not be affected by an increase in octane (I would think that this would depend on what the internal issue is...). Which I guess would make it indistinguishable from false knock? The AI says that my most likely culprit is bad gas. I don't like this theory, because I've already tried using gas from several different places and get no change in results. Considering the things I've already done to diagnose, a valve seal problem seems less likely at this point. I never see any blue smoke, and my oil consumption is relatively normal except under sustained (road trip) highway driving. So if oil is getting into my combustion chamber, it seems that it only happens under certain conditions. It also seems less likely that it's blowby. I'd think that if it were blowby that my knock would continue up to 7500 RPM and it never does.
I thought about this, and came up with a new theory. Fortunately, this one won't be hard to test. A while back, I noticed that the inside of my intake manifold was caked with oil and so I installed an FRPP oil separator. This seems to be doing a good job, but I've learned that under WOT, the airflow in the crankcase reverses because there is no vacuum to open the PCV valve. In this case, blowby gasses are expelled via the crankcase breather hose. I would imagine that when the airflow switches directions like this that there is momentarily greater pressure inside the crankcase than normal. What if, when the airflow switches direction, a slight buildup of pressure is pushing a puff of crap into my intake? If this was the case, it would explain why my knock always occurs at about the same RPM in my logs, and why it tends to step down and go away after an initial spike, even though the car is still building RPM. If this is the case, all I need is a simple driver's side catch can!
I went ahead and ordered a kit from Radium and am looking forward to some more tests. For the time being, the 91 SCT tune seems like it's the safest so I left that on the car. Let me know if any of you guys disagree with any of the thinking here. I'm no mechanic! Just doing the best I can.
One thing that I think that I can rule out completely though, is false knock. So my noisy transmission is good to go!
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- Thread starter
- #184
Radium driver's side catch can installed. I got this kit because it looks high quality and it's the only one that has a very nice custom bracket to mount it instead of a generic deal that you have to mess around with to use. The filter system seems top quality and I like that it has a system that bypasses the can in case the can fills up. As for the cons -- it's quite expensive. But you get what you pay for... I hope... The driver's side bracket is very cool and seems solid, but it's a tight fit. The bracket rests up against the OEM airbox which made me worry about rattling/false knock, so I put a small piece of dynomat on the side of it. When the can is installed, it makes it much more difficult to remove the breather hose and therefore the intake hose. The short rubber hose that runs from the can to the intake hose is so stiff that I have to remove the AN fitting instead of the OEM quick connect side in order to remove the intake hose.
Took it for a test drive to ensure no problems/noises, etc. and everything looks good. Will show some pictures after I get the passenger side installed and after that it's datalog time again.
As a side note, while I was installing this thing I put a flashlight inside of my intake hose and gave it a thorough inspection for signs of oil. I hadn't noticed any before, but this time I saw it. Streaks of oil stretching out from where the breather hose connects. Light and hard to see. I stuck my finger into the port where the breather hose connects and did get some oil on my finger. Then I flipped the hose upside down to see if any oil had made it into the Helmholtz resonator chamber (the reservoir on the OEM tube) and sure enough there was a tiny bit of oil in there. Just a couple drops. This theory is looking up. But why does my car like to spit oil out of the breather hose? I haven't noticed many other people having this problem... Fingers crossed...
Also, engine ate another 1/2 qt. of oil in the last 1k miles. I have been doing a lot of datalogging though.
Took it for a test drive to ensure no problems/noises, etc. and everything looks good. Will show some pictures after I get the passenger side installed and after that it's datalog time again.
As a side note, while I was installing this thing I put a flashlight inside of my intake hose and gave it a thorough inspection for signs of oil. I hadn't noticed any before, but this time I saw it. Streaks of oil stretching out from where the breather hose connects. Light and hard to see. I stuck my finger into the port where the breather hose connects and did get some oil on my finger. Then I flipped the hose upside down to see if any oil had made it into the Helmholtz resonator chamber (the reservoir on the OEM tube) and sure enough there was a tiny bit of oil in there. Just a couple drops. This theory is looking up. But why does my car like to spit oil out of the breather hose? I haven't noticed many other people having this problem... Fingers crossed...
Also, engine ate another 1/2 qt. of oil in the last 1k miles. I have been doing a lot of datalogging though.
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Fingers crossed, i know this has been a long saga for you. The Radium stuff always looks great and to me seems like they have put proper though behind their designs.
Coming from a workshop that dealt with a lot of 80's 911's, i remember reading 1 litre per 1000kms was considered normal in the manual.
Given we dealt with a majority of club track cars, oil was always part of the spares for a track day.
Coming from a workshop that dealt with a lot of 80's 911's, i remember reading 1 litre per 1000kms was considered normal in the manual.
Given we dealt with a majority of club track cars, oil was always part of the spares for a track day.
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@BackInBlack I’m confused, you replied to @steveespo that you’re running a stock tune, but then you posted results of a series of SCT canned tunes? Maybe I missed something but have you ever downloaded and tested a confirmed stock tune? Are you certain the “stock” tune on your SCT tuner is actually stock? Is it possible that your engine knock and fuel trim issues are related to your SCT tunes?
Way back in post #5, you crossed out your comment about using a stock tune, what did you mean by that?
Way back in post #5, you crossed out your comment about using a stock tune, what did you mean by that?
- Thread starter
- #187
Yeah I do have a stock tune. We loaded it via Ford IDS at build time using the VIN of the donor car. The reason I crossed out that line was because I decided that I shouldn't recommend that people immediately flash a stock tune if building a swap car like mine because you never know what kind of mods the engine might have. Now I'm recommending to keep whatever is in the donor PCM and then back it up before you change it.
In that datalog post, I was running a series of tests to try to prove or rule out false knock. So, more timing, less timing, and octane booster. I did a few more runs than this, including one on the stock tune but the stock tune log was pretty similar to the SCT 93 log so i didn't think it was useful to post. Every tuner I've been to refuses to tune my car which is why the SCT canned tunes are the only ones I have other than stock.
I did compare a series of datalogs a while back between the stock tune and the 93 tune and all of the datapoints look identical aside from the new one about knock at WOT. Personally I think the SCT tunes are probably slightly modified clones of the stock tune. There's little to no performance gains but they do seem pretty safe. My assumption was that the 91 tune would reduce timing a little and I think that was correct. I was able to rule out false knock with these tests.
Currently I'm running on the SCT 91 tune for safety and in preparation for another WOT datalog. If the 91 tune still has knock then there's no need to try the others.
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