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Area of the af map I can ignore

Practical Standalone Tuning

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Discussion and questions related to the course Practical Standalone Tuning

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Hi,

I'm tuning my car for track use only. When I get it on the dyno and put it on 4th gear, I can only reach the area like MAP @ 80 and rpm at 5k. Should I use lower gear so I can tune like MAP @60 and rpm at 5k. This is a track car and I'm wondering which part of the map I can ignore or no need to tune it precisely so I can save time on the dyno. Thanks!

It depends on the use of the car on track, if you have a lot of corners where the whole rev range of the car is being used, then you need to tune those areas, if you have a car and tracks that the car is essentially either off throttle, or at 100% throttle, then you can tune around the idle area, and just do some 100% pedal dyno pulls and the car is tuned. One of the people that I work with tunes his race cars that way, he has won championships with these tunes...

I would recommend the use of Logging for this issue as well, if you have an ECU that can log the correct channels (TPS, Load, Lambda) at a minimum of 20Hz, then you can log the data, do some laps, come back into the pits and then check the fuelling in the logs and make any changes needed.

In my opinion just tuning the 100% throttle areas and not the rest won't give a great result. Even if the car is at 100% most the the time it will always transition through other areas of the map when coming out of a corner, through a corner, into a corner, wet track and throttle resetting etc.

I tend to tune the 100% throttle areas first then extrapolate down in the vacuum areas what I think the engine will want. Then go through and tune these areas. Then I will start at 2000rpm and light throttle and roll onto the throttle till 100% and check the mixtures as I transition through those areas of the map, ensuring there is no lean or rich holes which could cause a surge. I then increase the rpm to 2500rpm and do the same. All the way up to high rpm i.e 6000rpm. Although doing it fairly quickly in the higher rpm to prevent water or oil over heating.

In a purpose built track car I won't get to fussy about have a perfectly mixture on transition (unless an endurance car when we need most fuel savings/economy) but usually withing 5% I am happy.

Thanks guys! Another question is for the ignition table , at wot throttle I have to set it to 37 degrees to get the max torque. At 15 degrees it got very little power like only one-third of what the 37 got. I think 37 is way too advance but if I go further the torque world increase but not much. Does it sound normal? I tried to listen to the knock but couldn't identify one. Knock sensor pick same noise between 28 and 37 degree. It's a 1.6 high compression NA engine.

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That sounds totally normal, you're reaching the MTBT (MBT) point, if you're not hearing any knock then it's not knock limited. Are you able to monitor the knock signal somehow? I have my Phormula KS4 hooked up to my Dynapack to record knock levels.

Thanks Chris. I'm using Phormula as well but I was using their headset to listen. Due to lack of experience I couldn't be sure there was no knock. I connected the stock knock sensor to link ecu so I can log the noise level and I dont feel like there was a knock occurred (see the attachment). Race this weekend hopefully everything is gonna be ok.

Attached Files
  • Screen-Shot-2016-10-28-at-10.46.39-AM.png
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37 degrees is a hell of a lot of timing on a high comp engine at WOT.

I think with most engines (from an LS V8 To Honda engines etc) I haven't ever gone this advanced.

Im not saying its not impossible, just something I haven't seen. Are you 100% sure your base timing and delay are set correctly.

Also for your data log, Not sure if I am missing something but it says you're only on 27 degrees.

Also with the knock level, that only works to display knock if you have set it up correctly.

What I feel is happening here is that you're putting 30+ degrees in your map but since your knock threshold is so low (170) and your knock levels are over the threshold the ecu will be pulling out timing so you won't actually be at 30+

I suggest turning off your knock control or raising your knock threshold up really high like 2000 and see what the timing does then and how the engine reacts. You might find you have gone past MBT or it starts to knock.

Once you hear an engine knock you can check the data log and see what the cylinder level was, you then know where to set your threshold (Although will vary on rpm)

I suggest checking out the webinar below on knock control in a link

https://www.hpacademy.com/previous-webinars/049-setting-up-knock-control-link-g4-vipec/

I'm sorry I didn't say it clearly enough. This map was set to 27-28 degrees at WOT so I could compare the torque and knock level to 37 degrees. As for the knock control it was set up to monitor the knock only so no timing was taken out. The knock level was the same between 28 and 37 degrees and torque had increased. Does it's mean I should be safe at 37 degrees from knocking and close to mbt. As for the base timing it's pointing to 10 degrees mark and no drifting when I increased the rpm. So I assume I should've set it correctly. Yes 37 degrees sounds a lot and i dun have confidence to run at this timing unless I'm 100 sure it's safe.

The increases from your dyno graphs are only 2.7bhp, that's not worth running an extra 9-10 degrees of ignition, I'd say that's your plateau and would leave it at the lowest ignition value possible, remember the courses MBT (MTBT).

Did you try brining the engine into knock at a lower load to set up the Phormula and knock monitoring correctly? just to be totally certain you have the right frequencies and gain, this will also help set up your knock thresholds.

I agree with Chris. If you're only seeing a small gain I would be taking the smaller value.

Also as Chris mentioned to ensure the knock thresholds are setup correctly you do need to get the engine to knock to see how the levels react.

Thanks guys. I double checked my base timing and it's off by 6 degrees. Last time the shop checked it for me and seems they didn't do it right. So now I set the offset to -195 compare to -189 before. I will use lower rpm to make the engine knock to set the thresholds. Thanks again for the help.

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