Hi guys,
attached you find my first map for my ’08 GSR with catback exhaust only, 93 octane gasoline; and 2 logs: 4th gear pull up to red line, and 2nd-3rd-4th-5th gear pull (not up to red line, but it’s significant).
This map is NOT finished, since WGDC correction is still disabled, BTEL table is not refined (it’s not a problem since the correction is disabled), etc but I’d like some opinions and advices from you.
As you can see, the main difference in comparison to the stock ROM is in WGDC table, then I played also with spark advance but I could not increase it much (just 1-2 degrees somewhere); about AFR, I leaned it a little but then I stopped because I’m worried about exhaust gas temperature becoming too high.

Here the questions for you:

1) Do you think the WGDC table is too aggressive? From your experience, it was better to use a lower boost pressure and a little more spark advance (if possible)?
In particular, if you look at the second log, you see that (as usual) in 5th gear I hit higher boost and loads: in other logs, load has some even higher spikes at 275%. From the boost and load values you see, do you think it’s necessary to lower the WGDC for high gears, or can I leave as it is now (same for low and high gears) without problems?

2) Do you have ideas for smoothing that load dip at around 3600 rpm, and the other one at around 5300 rpm? I’ve already tried to change WGDC but the dip is still there (even maxing the WGDC at 100%), and I’ve not so much margin to play with spark advance.

3) I can measure exhaust gas temperature but only just before the lambda sensor: which is, approximately, the maximum safe temperature there? I know that temperature read in the exhaust manifold (before turbo) would be more significant, but at the moment I cannot read it there.


Once my doubts are clarified, I will proceed to set the BTEL correctly, re-enable the WGDC correction and smoothing a little more the AFR during spool up.

Thanks very much for your help, I appreciate any advice
Stefano


ROM: http://www.megaupload.com/?d=55DZBRYQ or http://rapidshare.com/files/419234248/ROM.zip
Logs: attached below

 

You have stock mivec tables. I would tune those first before worrying about boost curves as that will alter your boost curve as well.

- Bryan

 

I would smooth out the timing changes as it tends to jump quite a bit through the rev range. Large jumps in timing can cause knock to be more likely. Also am I reading the AFR's right? Are you still in the 10's for much of the pull? Lastly check your wastegate duties and limits up top it looks like the passive WG duty is dropping at around 7000 RPM?

 

Thanks for your quick replies.

@ GST
Yes, I'm still on the stock MIVEC table. I've not enough experience to play with them (even if I know what they do) and in particular I have not enough info: for example, I don't know the injection phase so I don't want to risk to increase too much the valves overlap, making some injected fuel going directly to the exhaust...
I've already seen gunzo's MIVEC maps that pratically are your (GST) maps with some changes, maybe I can try using them but I don't like to copy whole things, I prefer to make them step by step learning what I'm doing.
About EGT, what do you think? Which can be considered a "safe" limit? I'm a little worried to lean more...

@Guru
- timing: you are right, I still have to smooth it better; even is some timing jumps are due to load jumps (so it quickly points to different area of the timing table)
- AFR: yes, over 5000 rpm I'm still in the 10s: I have started to lean it (my first target was 11.0), but the as I said I was worried about exhaust gas temperature, since I have seen some high values; honestly I still have to check EGT with stock rom in the same conditions, in order to understand how much I can lean.
- WGDC: after 7000 rpm the WGDC starts dropping, since at 7500 I have 70%. Do you think I have to make it drop earlier? (I forgot to say that I have stock solenoids and pills).

Thanks again, your help is really useful.

 

You can set both WG duties to 100% at high RPM as the stock turbo will always drop boost pretty fast. I keep EGT's at around 1550 F max. Some of your low load knock sums may be due to the difference between your low octane and high octane maps. See Tephra's post about this.

 

Just paste in Bryan's or Gunzo's MIVEC settings. Making your own is either a venture in theorycraft or tried and true experience. I believe Bryan's started out as the former and ended with the latter.

 

theorycraft, lol, I like that one.

- Bryan

 

Just wanted to comment on this... I was told by a very reputable tuner to never set the solenoid (GM 3port in my case) to 100% duty cycle as it can lead to premature failure.

anyone have any thoughts on this?

 

Maybe because you are over driving the coils.

 

In theory that makes sense but I haven't seen that in practice.

My personal Evo8 has been running a GM 3 port for over 4 years now with no failure and it runs 100% at spool and 100% 6000 rpm +

On evo 8/9, the OEM solenoid is 100% all the time

On the Evo 10, the OEM primary solenoid is 100% all the time

- Bryan

 

my thoughts exactly.... I mean, it's not like you're ever going to be at 100% for more than, what, 5-7 seconds??

not being a ME/EE, I can't really comment on whether or not it is more damaging to have a solenoid like this static open or to have it oscillating to the greatest extent that it can.

enough empirical evidence here for me to not worry about it thanks

 

We don't do it since you don't have very good control of the solenoid at 100%.

We also don't do it since we it can IN THEORY cause the solenoid to fail.

Most of the times I find that there is no difference in 95%-100% on stock turbo cars, so we just turn it down a bit.

Mitch

 

Hi Mitch

car is running great... but you & Chris now owe me a clutch

I'll probably shoot you two an email in the next couple days... had a couple of nerd questions I was hoping you would be kind enough to entertain.

 

For sure shoot it over Chris or I will be happy so answer any questions you may have.

MitchM@amsperformance.com


Thanks,

Mitch

PS-Sorry for the OT lol.

 

Thanks guys.
So during the w.e. I copy Gunzo's or Bryan's MIVEC map and check again; then I try to smooth timing. Finally, if I have still some margin on EGT, I lean something more the AFR especially at high rpm; I want to proceed carefully about this, I don't want to blow the turbo: already with the current rich mixture, I've seen some EGT spikes at around 830°C = 1526 °F, measured near the oxygen sensor (these values are not during 3rd or 4th gear pull, but after some hard driving for around 10 km).

I know that changing MIVEC will change also boost, but in general do you confirm that my current WGDC table is ok (and not too aggressive) also for high gears? Or it's better to lower it a little for high gears?

RPM WGDC
500 0%
1000 0%
1500 0%
2000 0%
2250 30%
2500 52%
2750 75%
3000 90%
3500 97%
4000 98%
4500 100%
5000 100%
5500 100%
6000 100%
6500 100%
7000 100%
7500 70% (or 100% again as suggested by Guru)
8000 0%


I will update you, thanks again for your help