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Can you provide guidelines on big cam Gen3 tune setup: Best Approach/startup base etc

Practical Reflash Tuning

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Long time standalone tuner but new to HPtuner. 2001 Corvette, bigger cam (230's I believe, unsure of remaining spec at this moment). Wondering what the best approach will be doing maf/sd both, and getting it to idle properly. Car starts untuned rough, but can stabilize fairly well, so I assume it can be done without having to commit to the 1bar SD OS? If I did SD I'd prefer to take the MAF out of the intake entire to have that power gain, and not have to retune twice, but that isn't an option in the immediate sense.

Figure I'll aim to get it running well enough so I can initiate logs, get maf dialed, then sd, then start working on idle once I can see the picture more clearly.

Any tricks/tips?

Post the tune file and I'll make a base tune for you. You can use the compare feature to see the changes I've made and adjust from there.

I wouldn't recommend removing the MAF as it won't gain much, if any, power from that. I personally tune the idle first, part throttle, then full throttle. It can be hard to tune part throttle with a car that wants to stall when you come to a stop.

The main tables to get right are:

- Idle RPM (typically a 200 rpm to the whole table works well)

- half the Proportional (ex. from 50 to 25) and Integral (ex. from 10 to 5) Enable RPM Error values to smooth the idle

- add around 6-8 g/s to Base Airflow

- add 2-4 g/s to Startup Airflow Initial and add 50 rpm to Delay

- add 1-3 g/s to Friction Airflow Initial

- reduce Cranking VE by 5-10%

- reduce Primary VE from 400-1200 rpm by 5-10% and blend to 2000 rpm

These steps will get you in the ball park. You'll have to log the idle airflow parameters to see how the changes affect the car. The goal here is to get the STIT and LTIT to +/- 2 g/s. Watch the Startup Airflow in relation to RPM to see if you need more or less. Some tuning of the throttle follower can help if you end up with a hanging idle.

Starting with a stock file, 2001 Corvette. So, I'll look specifically at those areas, most of which I recall from the worked examples and reading. I just need to go over the tables for that era ecu. If I can kick it off with getting the car idling fairly well, then I'll focus more on that to get comfortable with some processes. Hopin i dont take 8 hrs to get this done...lol.

I would have to use your file to give a base tune. The worked examples, or at least the ones I’ve seen last, don’t cover the topic enough to tune for a factory like idle on a big cam. I’m sending this from my phone so I can’t check to verify that, but use the info I’ve given you and make small (1-2 g/s) changes and you’ll get there quickly. If you’d like, send a pm and I can help you along.

Well, I've gotten into it here a bit. Just need to take time and get it all done. I've taken your direction though...we'll see how it goes. The worked examples were pretty disappointing. All stock vehicle, felt like a lot of parameters weren't discussed. It was helpful overall, in transitioning from standalone and OBD1 based stuff which I tuned for years and years, nearly day in/day out, but still feel like I am missing a lot of detail.

If anyone could take a look at this (possibly fill in or explain any errors I'm making), tell me possibly where I am going wrong. Tried a lot of different base airflow values. Unfortunately, my innovate won't work and am waiting on the serial cable and adapter. Tried to get this car to a base tune and at one point had it idling fairly well, but when I went to do SD correction, everything started falling apart. I logged, pasted by half, etc...felt like I was gettin mega sh*tty data from his narrowbands in the longtubes. Once I cleared his long terms car fell apart in how it ran. Overall his LTFT's were adding about 14% across the board.

Can someone please give me a base update, or maybe a renewed starting point. I'd like to get him running part throttle cleanly.

Attached Files

This is the last log we had where we had good idle characteristics enough to drive and start getting some data. Despite the worked examples, I feel like I am still lacking in the histogram setup area. This was the first drive. Andre, someone...need a little boost here.

Attached Files

Very helpful...lol.

I see this has been stae and hope someone will look at it.

I have a question on the Large cam 2005 P59 ECU, Gen3 LS. At idle there is LTFT of +25%. Is it really that lean or reversion? I added to the MAF calibration because the STFT were also adding 15+% and idling 1000rpm reset LTFT, they came back but much slower. STFT pretty stable +/- 5% mostly + with 1000rpm. CompCam 275THR9 cam LSA 109, and 71* overlap. lift is .550 int .530 exh

In Closed loop, after adjusting for the +25% at idle it stayed at near 0% so I think it needs the fuel to satisfy the stoich, but is it really needing it?

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