TD_D mod journey. From stock to the 'bastardmobile'

[Td_d]

So with the injectors on their way, I'm trying to get my head around providing the mechanic with a modified tune to accomodate the new injectors.

I would think that a modified injector scalar and the correct / published latencies should at least give me a safe base from which to retune the MAF scale? Is it that simple?

 

[Td_d]

I can live with relogging and starting from scratch given the upside from the bigger injectors! This is going to be fun...

 

[HolyCrapItsFast]

Kind of. You have to log to check the latencies all over again.

+1 :tup:

So basically your process will go something like this...

-Theoretical injector scale.
-Published latencies
-Install Ijectors
-Log
-Confirm and adjust latency (Ignore scaling at this point)
-Log
-Confirm MAF scale (Ignore idle trims at this point). If the entire MAF scale is off by some percentage +/- globally, then apply a correction to injector scale till it comes back to zero.
-Log
-Adjust MAF scale idle region only for idle trims.

 

[Td_d]

Phew... starting to read up on ROM disassembly... man, my head hurts...

 

[HolyCrapItsFast]

Yeah that's where I draw the line. :lol:

 

[Td_d]

Hmm... there's an interesting thought - Fuji, you might be interested in this - apparently you can use AFR sensor resistance and AFR sensor heater current to gauge EGTs.

I'm wondering how one would go about implementing this - I guess you would have to get the low and high operating range of the resistance? Been reading up on AFR theory, would be great to get a better idea of where EGTs are sitting to better tweak the fueling tables...

 

[Td_d]

Holy - are your timing maps for cruise lower than the non-cruise maps? Mine were set identical, and from what I'm reading that can resulting in knocking when you rapidly move from cruise to non-cruise conditions (read, mashing the pedal down).

 

[Td_d]

I'm looking the AVCS thread on Nabisco where Jeff goes through the whole theory and testing (and he was also using a similar size turbo) - and my maps, are quite markedly different. Which once again makes me think that no thought was put into it. On the up side, that means I can probably tweak the settings to get similar results to what you got George. I don't want to just go ahead and makes major changes to AVCS, as I know it can lead to knock very quickly.

Where would you suggest I start? Following the debate above, I should probably arrive at similar maps.

 

[Td_d]

That sounds like the process that was advocated on that thread - he did about 70 pulls in total...

For interest sake, here are the maps that he landed up on (with a GT30R). Markedly different from mine. Well, mine are downright crude to be honest - large blocks of single numbers.

 

[Td_d]

If I look at the overlap differential between mine and this process, it seems relatively intuitive - a lot of overlap is removed relative to my map at the low load, and a fair amount is added in that spool up, highload area (and surrounding cells).

Taking a closer look at my maps, they follow a similar logic - low / high - but are much more crass in terms of the gradations. Plus these maps above push the overlap quite a bit more in the high areas (which I gather is what George just did with great results).

 

[HolyCrapItsFast]

Holy - are your timing maps for cruise lower than the non-cruise maps? Mine were set identical, and from what I'm reading that can resulting in knocking when you rapidly move from cruise to non-cruise conditions (read, mashing the pedal down).

I have a GD so I only have the one table. :tdown:

ok, so this is how I would do it:

1. get the rest of the map squared away
2. make an avcs adjustment
3. make any required fuel adjustment
4. adjust timing (reducing timing at peak power/torque can make her faster, and additional timing at low rpms when you are rich will make it spool faster)
5. repeat 2-4 until you don't see noticeable gains.
6. adjust higher rpm timing
7. adjust higher rpm avcs


Basically, I would section out the AVCS tables and slowly make adjustments and dial it in. AVCS adjustments will change what fuel, timing and spoolup look like. If George has a better idea, I'd like to hear it, but when my trans is back in the car, I'll be spending a few weeks dialing all this in.

You da man! This is essentially what I employed only a bit more crude for my own purposes. The biggest thing that did it for me was more timing and fuel in the area where spool begins and continues till usable boost is realized. I chose to adjust my timing with the Dynamic advance tables instead of the primary table.

My AVCS is not particularly great but it does coincide somewhat to the diagrams that TD listed... somewhat. The thing to understand is that the best result as they relate to the turbo spooling, are going to be seen mostly from exhaust AVCS and very marginally from intake AVCS. Your torque curve are going to be more dictated by both but more so by intake AVCS.

I don't have much experience with adjusting exhaust AVCS so I don't think I have the poetic license to comment much further. Other than to say you guys suck for having it :tard:.

 

[Td_d]

I have a GD so I only have the one table. :tdown:


I don't have much experience with adjusting exhaust AVCS so I don't think I have the poetic license to comment much further. Other than to say you guys suck for having it :tard:.

Chuckle...

So more fuel and timing to ensure that it's building up heat. Gotcha, I'm curious to test this out. AVCS, I'll get going on after I put the new injectors on, as I suspect it's going to be very time consuming.

Could I see your fuel map, pretty please? I'm curious to compare versus mine, since I richened up the early spool areas markedly in correcting for the laggy spool originally, but did not up timing. I think that is probably key.

 

[Td_d]

Referring back some posts - what do you think of the AF sensor resistance / current idea George? It was squirreled away in one of the Romraider threads, but I'm trying to figure out how one could actually make it work.

 

[HolyCrapItsFast]

After I saw you post that I started searching the internet but that didn't last long. Not really sure how you would go about it. Maybe when I have some time I will investigate it further.

 

[Td_d]

If I'm not mistaken, I can already log both in Romraider and on standalone.

 

[Td_d]

Yup, confirmed - I can log both current and resistance of the stock AFR sensor.

 

[Td_d]

Aha!

"Look at EGT and keep it within 800-850C by means of appropriate AFR and knock limited ignition.
If your setup has no EGT sensor, look at AFR sensor heater current. It drops rapidly if EGT is higher than 820-840C.
This is probably a safe margin. "

Both the OEM sensor and Bosch used with an LC-1 WBO2 are zirconium oxide (ZrO2).
My car manual states the OEM sensor provides stable readings at 700C.

"
"For the Bosch LSU 4.2:
Typical operating temp: 750C
Heater shutoff at : 850C
Operating range up to: 930C (for up to 10 minutes continuous duration)
Max temp for sensor: 1030C (it may not be accurate after seeing this)"

 

[Td_d]

Shit, I think I've got a boost leak again... coming home today, starts stumbling at closed loop and going rich all the time. Idle's hunting, afr dropping and rising, and boost pressure is normally rock solid at -0.5Kpa - now rotating between -.46 and -0.48. Probably a vacuum leak, given the hunting idle...

And I don't have a compressor, or a boost leak kit.

 

[Td_d]

Sorted. That was easy, tightened up hoses around intercooler, throttle body and intake, removed and refitted all vacuum lines, and voila. back to -.5 bar, silky smooth drive. I really should get a boost leak kit.

 

[Td_d]

I think I must buy one, or make one - it's pretty easy from what I've seen. Only problem is I don't have a compressor :tard: