Ok. I'll wait before I do anything. I would think that we'd want what TS calculates, I can not figure out where they got their #s.
I'm sorry if I'm bugging you. Thanks!
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93 5.0 MSPNP2 tuning ?s
- Thread starter Skind
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Ok. I'll wait before I do anything. I would think that we'd want what TS calculates, I can not figure out where they got their #s.
I'm sorry if I'm bugging you. Thanks!
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Req fuel is an arbitrary multiplier, I change it all the time to get the fuel table to do what I want. I like my maximum ve to be no more than 180.... if you halve the req fuel you double the ve table and vice versa
Ahh... I think I understand, so the Req Fuel # doesn't necessarily have to be what TS calculates then.
Blown88GT
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You're not supposed to mess with the Required Fuel, unless you change engine displacement or injector size or AF ratio. You don't change it to change the VE Table. There is nothing "arbitrary" about it. Mathematics is never arbitrary, it is precise. It's an "ideal" calculation for Volumetric Efficiency. This is one reason I use a MAF, it is not an ideal calculation but an actual measurement of air flow.
Don't go there, unless you become an expert.
I will agree for certain applications such as a sequential injection install. I will adjust the required fuel if the idle ve or the entire ve table is low values with the "proper" req. Fuel.
Very low values at idle make things tough sometimes, a single digit change with a value of 20 is a 5% fuel swing.
Ms3 does not seem to have this issue, of all the ms3 cars I have tuned I have never once changed the req fuel after it has been calculated. My advice is solely ms2, microsquirt based.
The above statement about not changing it until you are fully comfortable/expert stands true I shall adjust my advice based on the skill level of the op
Ok. The only reason I was going to change it was to change to what TS calculated, which is 8.4. Because the tune that was in the car has 13. So, am I supposed to change to what TS calculated or just leave it be? I understand I'll have to dial in the VE table, but it appears I need to do that anyway. So, I guess I'm trying to make sure everything is correct before I do start dialing in the VE table so don't have to twice.
- Jul 7, 2005
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If you are updating the data fields in the TS calculation then I would say absolutely use the new required fuel. That is the whole reason it is there anyways. You are correct in needing to redial in the VE table, but you were already going to be doing that anyways.
The interesting thing is, I didn't change anything in the data fields, I just pushed the Req Fuel button to make sure it'd be the same as what the original tuner had in there and it is quite a bit different. If it would have came out the same, I wouldn't have questioned it. I'm just trying to go through everything to verify it is correct and trying to understand the system so I can get it running right, and to be able to make changes to the motor later too.
On one hand I'd just pay a91what to tune it for me, but I'd really like to learn how to myself. Heck, I wonder if he does paid one on one training?
Shout out to @a91what for doing a tuning/training session with me. He went above and beyond what he said he'd do. A big thanks!!!
The car runs way better than before. Drivablity is fun again. The only issue I'm still fighting is hot start and once the car is heat soaked it runs lean at idle. MAT is up at 170* so air density correction is pulling 17% fuel. Hence it being lean. So, should I adjust the VE table in the idle range to richen it here? I tried it, had to add about 8% to get the wideband to match the afr table. And it runs smoother, but I thought we had the idle dialed in. Should I adjust something else instead of messing with the VE table? I should add that before it gets heat soaked like driving around MAT are around 140-160* and AFR are fine idle is fine. But if you stop and idle for a long time and or start after sitting 10-15 minutes it does this.
The car runs way better than before. Drivablity is fun again. The only issue I'm still fighting is hot start and once the car is heat soaked it runs lean at idle. MAT is up at 170* so air density correction is pulling 17% fuel. Hence it being lean. So, should I adjust the VE table in the idle range to richen it here? I tried it, had to add about 8% to get the wideband to match the afr table. And it runs smoother, but I thought we had the idle dialed in. Should I adjust something else instead of messing with the VE table? I should add that before it gets heat soaked like driving around MAT are around 140-160* and AFR are fine idle is fine. But if you stop and idle for a long time and or start after sitting 10-15 minutes it does this.
I was hoping I could somehow keep the MAT sensor in the #5 runner and change the tune to not have the lean hot start and long idle heat soak issues. That way if I ever went back to positive displacement it'd see the boosted air. I may just have to go ahead and try moving it for now, since I'm centri blown right now.
How come the MAT sensor in the #5 runner doesn't cause this issue with the stock computer?
How come the MAT sensor in the #5 runner doesn't cause this issue with the stock computer?
Let's back up a second. As I'm out here trimming the bushes, my mind is wondering. Other than the few seconds after start up, the MAT sensor reading should be exactly what the air temp is, and if the MAT density table is correct, then theoretically the afr should be correct. So other than the few seconds after start up, if the afr is lean after that, then my VE table is probably wrong. Am I incorrect?
Better get back to trimming the bushes before my better half see me......
Better get back to trimming the bushes before my better half see me......
I wouldn't assume it doesn't... I have never looked at web readings from the stock eec to compare.
Now there is the option of tuning the mat/clt correction curve. This will blend the clt and mat sensor inputs together at the % you specify at that flow value. It is a little tricky to setup but works very well once you tune it.
Doing this will require a fuel tweak as you get it dialed in. Look at my tech thread for more details.
The mat air density table is correct, at least it is when my car is under load. I have noticed the same discrepancy at idle... I never adjust the curve because it affects the fuel when I'm under boost. Back to back pulls heat soak my blower, the first pull is 160* tops the third will see 195-205* mat temps with the same afr reading.
See my above post about the clt/mat blend table. The table I posted in the thread is aggressive and likely to much for your application.
I did read your post about the MAT/CLT blend table. And I actually already tried your #s just to see what would change. At idle it actually pulled more fuel than with out it. I understand these #s are incorrect for my setup, just thought I'd see what would change. I guess I'm not understanding what it does, I thought at low air flow it would "subtract" some from the MAT reading to be more realistic. Am I thinking incorrect?
Your thinking is reversed, numbers will be 'higher'at all times (closer to clt value) You can see the new mat temp in the datalog after the blend correction. The heatsoaked mat value will appear to be closer to the normal short idle mat value. You will need to enrichen the idle values to compensate.
Make the curve taper off very sharply you want almost no blending at cruise.
You should also log 'flow' to see the flow # so you can build the curve. If it does not exist you can create it in megalog viewer with a custom field.
Flow would be- [load] * [rpm]
Flow would be- [load] * [rpm]
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