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The Official Tuning Thread


Infamous1

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2. Start the car on your base map and monitor short and longterm fuel trims and adjust your intake calibration to zero out the trims while free revving in neutral up to about 2.1 volts.

3. Adjust the intake cal under load and partial throttle until it exits closed loop.

4. Make a pull at wastegate boost and adjust the intake cal to hit the target afr's.

 

Does a stock intake need to be calibrated? My guess is, "It shouldn't need to be calibrated, but it does..." I've been curious if I should play around with the Enginuity MAF tool.

My '05 LGT

My '07 Supercharged Shelby

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Does a stock intake need to be calibrated? My guess is, "It shouldn't need to be calibrated, but it does..." I've been curious if I should play around with the Enginuity MAF tool.

The new MAF tool makes closed loop scaling very simple. :)

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Where would you pull timing, from the base table or the advance? What is a good baseline for AFR on 100 octane on a TMIC stock turbo car? I am thinking 11.5 then go up from there...

 

11.5 is pretty conservative for race fuel. If it's 100 octane unleaded, that's about right as a starting point. If you are talking about 110 to C16 leaded I'd start closer to 12:1.

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FYI found this torco calculator sounds like 32oz to tank of 93 octane makes about 99-100 octane

 

Don't no if the rating of 128 for torco is correct though.

 

http://www.2k1vert.com/c5/torco_calc.xls

:rolleyes:"All right, brain, I don't like you and you don't like me - so let's just do this and I'll get back to killing you with beer." :spin:

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What's the best way to run wastegate boost only - set the wastegate high and low table values to 0?

 

As for timing, what's a conservative starting point? Would using the Primary Ignition Values from the Cobb Stage 2 map be a good start? Then decrease timing by a few degrees across the board? Or just in the high load cells?

 

Dave

 

I run wastegate boost while I first tune in fuel.

________

Teen Girl Live

Edited by Legacy_GT_Pilot
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What's the best way to run wastegate boost only - set the wastegate high and low table values to 0?

 

As for timing, what's a conservative starting point? Would using the Primary Ignition Values from the Cobb Stage 2 map be a good start? Then decrease timing by a few degrees across the board? Or just in the high load cells?

 

Dave

 

You need to log to get an idea of where your load is at during a WOT run. Cobb maps are pretty conservative so that should be fine. Alot of people prefer a flattened out Advance table to monitor knock a little easier.

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Here's another question:

 

Why can't OL fueling, WOT at least, be tuned similar to tuning timing? For example, if there are LGT's out there running 11:1 and tapering to 10.6 at redline, why can't one bump fueling a tiny step leaner at a time until knock? (Similar to tweaking timing). I see several issues, such as not knowing what the AFR really is in the absence of WBO2, different gears would react differently, tip-in, etc. I've been tempted to run 11:1 to 5Krpm or so but know that benefit will not outweigh risk, especially in the absence of AFR data. I'm not playing this game, but curious as to the rationale why this would be a poor move.

My '05 LGT

My '07 Supercharged Shelby

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Here's another question:

 

Why can't OL fueling, WOT at least, be tuned similar to tuning timing? For example, if there are LGT's out there running 11:1 and tapering to 10.6 at redline, why can't one bump fueling a tiny step leaner at a time until knock? (Similar to tweaking timing). I see several issues, such as not knowing what the AFR really is in the absence of WBO2, different gears would react differently, tip-in, etc. I've been tempted to run 11:1 to 5Krpm or so but know that benefit will not outweigh risk, especially in the absence of AFR data. I'm not playing this game, but curious as to the rationale why this would be a poor move.

Timing is more consistant then AFR. AFR can vary from a dirty filter to different gasoline. I wouldn't even think about leaning the fuel out without a WBO2, too many variances.

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For fueling I usually target right about 11:1. Then I'll add boost to a level that corresponds to where the turbo used is most efficient. Then I'll add timing to see if that gets anywhere. I usually won't touch AFR unless the car seems particularly knock prone (then I'll go a bit richer), or if added timing doesn't make a substantive difference in power, at which point I might try a little leaner and take out some timing.

 

The overall strategy depends on the usage of the car as well. For a car that is destined to spend a lot of time at the track (road race) and consequently run at high load/high rpm a lot, the tune should be richer, run more timing and a bit less boost to help control EGT's. A drag racing map can be leaner, run more boost and less timing, since EGT control is less of an issue with the relatively brief time spend at WOT.

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With respect to #8 below, how much would you expect to have to tweak timing as you raise boost from wastegate pressure (~15PSI) to 20 or 22PSI assuming the AFRs remain good? Does timing typically need to be retarded a few degrees under high load, at peak boost? Any further guidance here?

 

Dave

 

Yup, the steps are pretty simple. Follow the formula and get good results.

 

1. Create your base map with appropriate timing and fuel values as well as all other settings like boost cuts, rev limiters, injector settings, etc.

2. Start the car on your base map and monitor short and longterm fuel trims and adjust your intake calibration to zero out the trims while free revving in neutral up to about 2.1 volts.

3. Adjust the intake cal under load and partial throttle until it exits closed loop.

4. Make a pull at wastegate boost and adjust the intake cal to hit the target afr's.

5. Add timing a couple degrees at a time until it doesn't make any more power.

6. Save your wastegate map and turn up the boost.

7. Adjust fuel

8. Adjust timing.

9. Setup launch control and FFS if available.

10. Drink Beer.

________

No-Fault Insurance Forum

Edited by Legacy_GT_Pilot
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With respect to #8 below, how much would you expect to have to tweak timing as you raise boost from wastegate pressure (~15PSI) to 20 or 22PSI assuming the AFRs remain good? Does timing typically need to be retarded a few degrees under high load, at peak boost? Any further guidance here?

 

Dave

 

If you are starting with a stock map, you'll need to chop a bunch of timing out of it, particularly up top. I'd start your basemap out by taking out about 10-12* up top, 6-8* at torque peak and smoothing it out in between. Keep your transitions smooth and timing steps modest. Set your AFR's while running wastegate boost. Then dial in your boost. Then try adding back timing about 1* at a time. If you aren't gaining at least 4-5 whp from each additional degree of timing I'd take it back out. No sense in bringing the car that much closer to the knock threshold for a negligible gain.

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Thanks for the info. I will be street tuning, so I won't be able to see the HP/TQ increases resulting from changes in timing. In this case would you keep advancing timing in small steps until the ECU begins to sense a little knock and retard timing, and then back things off a few degrees from there? Is this approach too aggressive?

 

Dave

 

If you are starting with a stock map, you'll need to chop a bunch of timing out of it, particularly up top. I'd start your basemap out by taking out about 10-12* up top, 6-8* at torque peak and smoothing it out in between. Keep your transitions smooth and timing steps modest. Set your AFR's while running wastegate boost. Then dial in your boost. Then try adding back timing about 1* at a time. If you aren't gaining at least 4-5 whp from each additional degree of timing I'd take it back out. No sense in bringing the car that much closer to the knock threshold for a negligible gain.

________

Kitchen Measures

Edited by Legacy_GT_Pilot
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Thanks for the info. I will be street tuning, so I won't be able to see the HP/TQ increases resulting from changes in timing. In this case would you keep advancing timing in small steps until the ECU begins to sense a little knock and retard timing, and then back things off a few degrees from there? Is this approach too aggressive?

 

Dave

You can use datalog information from the same stretch of road in comparable temps. Also Airboy's spreadsheet has somewhat of a road dyno tool.

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Question: Does flashing a new Base map to your ECU reset the Long term Fuel Trims?

 

I just had an o2 sensor die but had to drive on it for a couple days until the dealer got my new sensor in. Mileage seems to be back to where it was before (21ish city) but I wanted to double check. The o2 sensor that came out was pure black. Must have completely died.

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Question: Does flashing a new Base map to your ECU reset the Long term Fuel Trims?

 

I just had an o2 sensor die but had to drive on it for a couple days until the dealer got my new sensor in. Mileage seems to be back to where it was before (21ish city) but I wanted to double check. The o2 sensor that came out was pure black. Must have completely died.

Yes, it is similar to a hard reset with the negative battery terminal.

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Here is a question.....

What is everyone's strategy to prevent knock after shifts?

I tend to get this every once in a while :mad:

 

Unfourtunately the answer for me was to shift slower. Fast shifts on my LGT cause a bunch of pulled timing in the next gear, even though there were no knock events. This drove me crazy until Cobb tuners explained that they see it and the fix is to just shift slower.

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