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The timing table is a bit conservative, but timing is not as much of a factor as AFR is on turbo applications. Eg. adding 2-4 degrees of timing to your latest table might increase output by 5-10hp, changing the AFR from 11.5 to 12.2 might increase output by 20-30hp. Most tuners have more experience with tuning NA applications which for the most part is the opposite and are very timing centric. You need to dial in your VE first before being overly concerned about your timing. Make sure you have a good AFR map to target for your application.
Originally Posted by SimBa
Alright, so check it out. Pretty happy with how this turned out. I got the right aux cable and ran the headphone output from the @FWLRtuning Knock Detective into my phone. I was able to use that as an "external mic" when recording.
I believe my boost controller might be contributing some noise to the audio because it's mounted on my valve cover, so I plan to try to isolate/relocate that.
I'd be curious to hear people's thoughts. To me, it sounds like there's slight knock at about 3k RPM. Example around 36 seconds into the recording. https://youtu.be/9IjuVvIXe94
Here's my AFR table. I think it's pretty reasonable, but feel free to critique. I could probably raise the target by a few points at the top end (IE 11.3->11.5), but I'm not pushing that much boost, so it's not really relevant for now.
I'm usually pretty close to those targets, if anything I'm a bit richer.
Most of the research that I've done has said that for power output AFR's are less important than timing. Haltech made a video on this, but I'll need to go back and rewatch it. I'm not saying your wrong, just that it's contradictory to what I've heard from others. I do appreciate the input and discussion, and I'll keep doing my research. I'll do some fine tuning on my VE table as well, because I am dipping into the low 11s at some points.
Six,
In the past I've done that, and I'm pretty sure that's what led to my retarded timing in the original post, but I was confused because I kept retarding the timing and what I thought/think is pinging wasn't going away. You make a good point though, unless I'm way way too advanced, the pinging should go away with a few degrees of timing. Considering the timing tables I've started with in the past have been considered safe base maps, that's probably not the case. I'll try to take the car back out soon and play around with the timing in that area and see if the sound persists.
Both your later timing and AFR tables look ok. I have not looked at your tune and do not know what is going on with your actual timing in use. As per my previous post, NA is different than turbo in regard to tuning. The timing is mainly moving the temperature between the cylinder and the exhaust. The fueling is the main cooling trend. Anything below approximately 12:1 is reducing combustion chamber temps.
What is your spark plug gap?
Some engines have to run a much lower AFR's than 12 and some will run less than 10deg of timing. Especially high compression direct injection engines. For this application if you're a few degrees shy of ideal it's not going to sacrifice much output.
That dyno graph doesn't look too far off from what I'm seeing, but with the quality of data that I've been able to collect I think it's probably apples to oranges.
Spark plugs are NGK BKR7E gapped at 0.030" if I remember correctly. Stock NB1 coils.
Maybe this is a silly question, but our barometric pressure here in Boise is about 90 KPA. This was already brought up, but for me, I would think 10 PSI would be ~160 KPA (IE 90 KPA Base + 70 KPA Boost), while someone with a base pressure of 80 KPA would say 10 PSI is ~150 KPA.
Is that correct, or do most of you refer to boost pressure as pressure above 100 KPA? I guess that's gauge vs absolute pressure, but might as well make sure we're talking the same thing.
Ted, I remembered someone saying that earlier in the thread. I was able to get KPA to display on virtual dyno earlier, so I'll use that going forward.
FWIW I've been targeting 158 KPA for the graphs I've posted so far, although my boost control is not super accurate so I'm often above that. Would it make sense to go to open loop for more consistency?
The previous dyno graph was 10psi at sea level which would be 168KPA. I would say if your setup is similar and you're at 158KPA than the outputs might be about the same.
Alright, starting to feel like I'm making some progress. I've spent the past couple evenings in the car with the det cans on, mostly just listening and getting a feel for how the engine sounds. I played around with the timing in the area I thought was experiencing knock (~3K light load) and pulling around 6 degrees of timing made no difference. I've also noted that it is more apparent when stabbing the throttle. I thought this was related to the sudden load increase on the engine, but am thinking now that it has to do with AE and the rapid increase in injector duty cycle. I emailed back and forth with FWLR a couple times and he said he was 99% sure the sound I was hearing in that video was not knock.
I've also found a road that has been better for doing pulls. Switching to 3rd gear did seem to make a large, positive, difference in the data. I haven't played with the spark map too much from what Curly gave me. For now it seems close enough, and a dramatic improvement over what I had before. Here are two pulls with different boost levels. Different days, but same road and similar temperatures. The car had less fuel on the second day, I played with that in the weight settings a bit, which usually resulted in 1-2 HP less on the higher boost run. Depending on the smoothing it showed a 7-10 HP gain
I also switched to open loop boost control, as I was suspicious of the consistency of the "simple" closed loop option that I was using previously. I figure one less variable is better.
The lower boost was around 160 KPA while the higher boost was around 180 KPA, so that's about 3 HP per PSI. I did do a boost leak test not long ago and did not find any leaks. I'm using a very old style of intercooler shown here.
Pretty happy to be seeing over 200 HP now, but 3HP/PSI seems like there's a bottleneck somewhere.
I'm also curious, do you guys ever look at RPM/S when tuning? It seems like it would be pretty dependent on what the road is doing, but given good conditions it seems like it would be useful to see how happy the engine is.
Again, I appreciate all the comments and discussion.
Good to see it getting dialed in. If you want to see what octane + timing can do, go watch some of my drag racing and tuning videos on my channel. I'm on methanol, running about 28 degrees of timing at 30 psi boost, no intercooler. And it doesn't knock. And it hauls the mail!
Good to see it getting dialed in. If you want to see what octane + timing can do, go watch some of my drag racing and tuning videos on my channel. I'm on methanol, running about 28 degrees of timing at 30 psi boost, no intercooler. And it doesn't knock. And it hauls the mail!
What the... 28 at 30 PSI is insane. I saw one video of your channel of your crash (RIP), but I'll definitely go back and check out the others. I'm always hungry for tuning videos and info.
I took the car out and did some spirited driving while listening to the knock sensor today and it sounded clean, so I'm pretty happy about that. I'm going to be busy this weekend with a wedding (not mine), but might do some more spark tuning next week. I played around with a few degrees and heard some loud pops through the sensor, so I think I'm pretty close to maxed out on this 91, but again, this is a big learning experience for me.
Where did your timing map end up? I'm tuning a local friends car and the timing map I created for him looks almost exactly like your revised map on the post from 09-06-2024, 10:24 PM.
It's still conservative when comparing to Curlys 28* @100kpa and -1* per psi rule.
That said atmo pressure here is ~78kpa, so 100kpa is already 3psi relative boost pressure, so I'm not sure how accurate that rule would be since I usually treat my 80kpa row like most other's 100kpa row. I know 100kpa is 100kpa baro pressure wise, but there's got to be a difference between an easy breathing 100kpa atmo and 80kpa +3psi of hot air from a turbo tuning wise.
With a good intercooler I suspect you will find the timing tables don't vary too much, as long as you are in the efficiency island of your compressor. This also assumes you can source decent fuel, but altitude usually equals 91 at the pump.
Where you really get hammered is PR. 240kpa is a PR of 3 for you, 2.4 for sea-level. This can take you off the compressor map and requires way more hp (pumping). Remember to correct for mass airflow on the horizontal axis (IOW you move both up and to the right when compared to a sea level car). Brutal.
Currently have this loaded up in the car. Ran around 190-200 KPA at autcross this weekend on 91 and the car seemed to be happy.
I'd like to get back out and spend a bit more time with it sometime soon.
Where did your timing map end up? I'm tuning a local friends car and the timing map I created for him looks almost exactly like your revised map on the post from 09-06-2024, 10:24 PM.
It's still conservative when comparing to Curlys 28* @100kpa and -1* per psi rule.
That said atmo pressure here is ~78kpa, so 100kpa is already 3psi relative boost pressure, so I'm not sure how accurate that rule would be since I usually treat my 80kpa row like most other's 100kpa row. I know 100kpa is 100kpa baro pressure wise, but there's got to be a difference between an easy breathing 100kpa atmo and 80kpa +3psi of hot air from a turbo tuning wise.
What Ted said. It's really turbo/setup dependant.
The new fancy turbos love high PR, but you need to have the knock resistance and IC capabilities to support this.
For context - I was trying to update the firmware on my ECU (Speeduino) to one of the latest stable branches, but had some issues due to the 36-2 trigger wheel. Because I was messing with that, I redid my base timing again and ended up changing the trigger angle slightly.
I ran the car last weekend at autocross and it felt great. Made a good amount of power and seemed to pull well/happily. I am currently running around 180 KPA, open loop.
After messing with the base timing, I took the car out last night and threw in my earbuds/detcans. I loaded the car up in 5th gear and right around 3300 RPM & 170 KPA I started to hear some knock. Tried again, same thing. Pulled some timing, did another test, rinse and repeat until it sounded clean.
I ended up having to pull a good amount of timing at lower RPM, higher boost. I was just checking for knock, and not trying to figure out power level or do virtual dyno stuff.
I rebinned the table later and pulled this from the restore point comparison screen so it would line up better with previous tables in the thread. Some numbers are red due to the comparison, but that can be ignored. The 156-184 KPA, 3100-3800 RPM area is the point of interest. Sorry for the low res. I adjusted the binning on the table and had to pull this from the restore point screen.
I didn't notice much, if any knock anywhere else in the table. I ended up rebinning the table to give me a bit more resolution in the 3-4K RPM range, so now I'm here.
I'm curious about the technique that I used. Is it good practice to get the car super loaded up (IE Low RPM, high gear) to do a pull to check for knock, or is it better to start at a more realistic RPM/Gear?
Pulling timing feels lame, because... like... losing power (I understand that's not really the case if you're getting knock, but still). As I thought about it, that part of the table probably isn't getting hit most of the time I drive the car.
09-09-2024, 10:10 AM
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