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I am working through my 98 tune after after finishing with my E85 tune (modelled multi-fuel) on my car (first time tuner). My fuel table is getting pretty close so feeling pretty happy about that. I have a bit of concern about the nuances of ignition timing which I would like to get more experienced opinions on.
With my E85 tune, the car didnt really care what the timing was. I threw together a map based on a log I had from my stock ecu via OBD/Torque Pro - essentially following key points in the load/ignition timing. There was no knock anywhere (except one spot I will mention below) and it felt about the same as it did on the old ECU. When I swapped over to pump 98, I found that I naturally had to pull quite a bit of timing out to avoid knock, but I am concerned I may have over-compensated. I went and checked out your webinar on EGT and got educated on the matter (another great watch). Based on what you are saying it can make quite a big difference to temps and our little milk bottles already run quite hot apparently. I have a Link CAN Lambda+Bosch LSU4.9 sensor which is the closest thing I have to an EGT reading so I am basically in the dark in that respect.
I am fairly confident that I am very much on the conservative side with my timing, so more than anything I want to know if I am not being OVER-conservative? :)
I have got in contact with a local tuning shop and they are happy for me to use their dyno to dial in the MBT ignition timing, but I will not be getting up there for a little while yet. I just want to make sure I am not going to melt anything in the meantime.
I would also like your opinion on a knock event I am hearing (not showing up in software):
- very intermittent, not manually repeatable
- more commonly appears in the first 15minutes of operation
- On occasion during idle, and in the range of 2000-3000rpm and 50-80kpa but nowhere else.
I dont recall ever hearing it while on the ethanol and no adjustments to fuel or timing seem to change it. Is this phantom knock or should I be looking into it further?
a few of the key details:
Link G4+ Plugin ECU
Link G4+ Knockblock
GSC 272intake/274exhaust cams
MAP EF2 Turbo with 21psi wastegate
Thanks in advance for any info!
I've tuned plenty of EVOs over my years so I can offer my opinions. First I would say that you're likely to still need more timing on E85 to reach MBT (which you should be able to comfortably do). You haven't really mentioned what you're running in the way of boost other than the turbo has a 21 psi actuator - Are you just running wastegate spring pressure or are you above that? At 21 psi on E85 I'd be expecting an EVO 8 engine to take perhaps 15-18 degrees through the midrange and north of 20 degrees at higher rpm.
On pump gas you're only running around 4 degrees at the same boost. EVO engines normally are quite knock sensitive around peak torque on pump gas but I'd still expect you may be able to get away with a little more timing (perhaps another 2 degrees) with safety. You should be able to then ramp this up quite as the rpm increases - I'd expect somewhere in the region of 14-16 degrees.
I can't really comment on what you're hearing but it sounds like false knock, particularly if you're hearing it at idle as it's essentially impossible to make an engine knock at idle since there is no load on it. Provided you've correctly configured the knock control in the ECU you should be able to use the logging to help back up what you're hearing. You can also try pulling a lot of timing in an area you think you may be hearing knock - If it doesn't affect the sound then it's likely you're hearing a mechanical noise.
Thanks for taking time to reply. Knowing you owned a very serious Evo yourself and have no doubt tuned a couple million of them (haha), I imagine you know them like the back of your hand!
My apologies on the vagueness. As you can probably tell from the wastegate tables, the spring is 21psi so I have the wastegate table zeroed for pump fuel. The previous tuner had peak boost set to around 24 perhaps 25psi based on the gauge I installed. I have no interest of exceeding the 23psi mark with my own hand - it is plenty fun enough at that boost and reliability is important to me at the moment.
You are again showing your experience in regards to the E85 map - You were right on the money for the the estimates based on the previous ECUs tune. Compared to the logs I pulled out of that, I have dropped around 20% out of it. I am again stressing far more about being safe here rather than sorry. Even the previous tune which was done by a tuning shop had less timing in it than you have indicated, so that leaves me wondering if maybe it was knock limited or he was just being cautious as well. Not really interested in finding out on the road either way! I am using those numbers as my "maximum" for now basically.
I think the mistake I made was basically pulling all but 30% out AGAIN from that map when I went to pump. When I heard pump timing needed to be "far less" I interpreted that as being across the board rather than in key load areas. I really appreciate you providing me with some specific numbers which should work for those key areas. As I mentioned, I am looking at getting it to a dyno, but I wanted to feed a little more timing into it beforehand to ensure that it was not getting too hot in the meantime.
I do realise (thanks to your incredible webinar content) the best way to handle this would be to add a little bit at a time until you hear knock (and confirm the ECU is correctly hearing it while I am there) and then go back few clicks. Thing is, after listening to a few examples of knock via your videos and from other places, the sound to my ears is extremely similar to my noisy valvetrain (bloody ticking lifters). That combined with the now almost certainty that the other noise I am hearing is NOT knock, I have lost confidence in my ability to hear it if it does happen. I am organising for an experienced local tuner to put his ears to it in a few weeks and tell me the right of it.
Once again, many thanks for providing myself and many others with this kind of support on our journey.