Tuning a 1g with Web Cams and 2g pistons

[96bmwm3]

I have a '90 Talon with 2g pistons and Web Cams. What type of tuning details should I be aware of? Can I run typical timing advance up to ~20* at redline? Should I run more or less fuel because of these mods?

Just looking for general thoughts on how these 2 internal engine mods will alter my tune?

 

[GVR4592]

It would probaby be safer to run lower timing, similar to what a 2g does. If you get in contact with Jeff(Keydiver) he'll be able to re-burn your chip for you to get the lower timing values. With the cams there will be an increase in airflow which could make the engine run lean, Jeff might be able to correct this with his chip if you're sending it back to him for the timing changes. You can do the fine tuning with your safc and datalogger.

 

[96bmwm3]

Thanks for the reply. As I think you know, I have a stage 3 Keydiver chip. I told Jeff what my setup is and by the looks of my logs he may have already accounted for the 2g slugs by lowering overall timing advance. I'll have to ask him. Your response has answered a few of my questions, one of which was why is my timing not advancing upwards of 20*? The log below gives a bit more data. This particular log doesn't run all the way to redline, but in subsequent logs I reached about 15* at 7k.


Timing TPS RPM Knock
24° 73.3% 3063 0
21° 100.0% 3094 0
18° 100.0% 3125 0
15° 100.0% 3094 0
14° 100.0% 3125 0
12° 100.0% 3156 0
12° 100.0% 3188 0
11° 100.0% 3219 0
11° 100.0% 3219 0
11° 100.0% 3281 0
11° 100.0% 3313 0
11° 100.0% 3375 0
11° 100.0% 3375 0
10° 100.0% 3438 0
10° 100.0% 3469 0
10° 100.0% 3531 0
9° 100.0% 3563 0
10° 100.0% 3594 0
10° 100.0% 3656 0
9° 100.0% 3688 0
10° 100.0% 3750 0
11° 100.0% 3781 0
10° 100.0% 3844 0
10° 100.0% 3875 0
10° 100.0% 3906 0
10° 100.0% 3969 0
10° 100.0% 4000 0
10° 100.0% 4063 0
10° 100.0% 4094 0
10° 100.0% 4156 0
10° 100.0% 4188 0
10° 100.0% 4219 0
10° 100.0% 4281 0
11° 100.0% 4313 1
10° 100.0% 4344 1
10° 100.0% 4406 1
10° 100.0% 4438 0
11° 100.0% 4500 0
11° 100.0% 4531 0
11° 100.0% 4563 0
11° 100.0% 4594 1
10° 100.0% 4625 1
10° 100.0% 4688 1
10° 100.0% 4719 0
11° 100.0% 4750 0
12° 100.0% 4781 0
12° 100.0% 4813 0
12° 100.0% 4844 0
12° 100.0% 4906 0
12° 100.0% 4938 0
12° 100.0% 4969 0
12° 100.0% 5000 0
12° 100.0% 5063 0
12° 100.0% 5094 1
11° 100.0% 5094 1
12° 100.0% 5125 0
11° 100.0% 5156 0
11° 100.0% 5219 0
12° 100.0% 5219 0
12° 100.0% 5250 0
13° 100.0% 5281 0
13° 100.0% 5313 1
12° 100.0% 5344 1
12° 100.0% 5375 0
13° 100.0% 5406 0
13° 83.9% 5406 0

 

[andymoraitis]

You're picking up enough knock to pull one degree of timing in quite a few RPM ranges so I'd add a bit of fuel in those areas to keep the timing curve smooth. Nevertheless, 2G maps peak at16 degrees of timing above 2.1 g/rev on the highest airflow table so if you've hit 15, it looks like you're on the money, but I'd check with Jeff anyway to verify what timing settings he burned into the chip.

I know the 2G ECU holds timing at 7 knock counts and retards 1 degree of timing for every 3 counts over that in subsequent incremenents. I'm not sure about the way the 1G ECU works although I know it's more aggressive with knock retard since the timing values are usually higher. Perhaps someone with more knowledge of the 1G ECU can jump in and quote the exact values.

Either way, if you eliminate those dips, you'll be on the right path. You might want to log for knock just to see what the actual values are.

 

[96bmwm3]

I just received my 650cc injectors today. They are installed, but I haven't run the car yet. I started talking with Jeff O. (KeyDiver) about updating my Stage 3 EPROM that he developed for me. In our discussions I mentioned my current S-AFC settings because I wanted him to add a bit more fuel at specific RPMs (as you saw in my previous post, I was getting knock in a few places). Below are my S-AFC settings and my current EPROM configuration.

Jeff was baffled as to why I should need so much extra fuel considering his chip was setup to shoot for 11.0:1 afr already. He was concerned that there is another issue and suggested that I not throw more fuel in to reduce knock but to pull timing instead. My base timing is 5*. Is this maybe too high since I have 2g pistons?

I need some help here ... I tuned with my new wideband to get those settings and as you can see from my previous post, I am still getting a little knock know now and then.

S-AFC settings:
> LO HI
> 1k +2 +2
> 2k 0 +4
> 3k +2 +6
> 4k +6 +11
> 4.5k +6 +11
> 5k +7 +11
> 6k +7 +9
> 7k +7 +9

 

[96bmwm3]

Bump... Someone's got to have a comment here...?

 

[brute]

Edit: pull timing instead of adding fuel.

 

[nightspeed87]

hmm.. im going to be useing 2g pistons also? i know the 1g has more aggressive timing, so will that benefit the powerband with 2g pistons (as in give more power on 1g timing than 2?) and is there anything to worry bout , any drawbacks opposed to these pistons.... (im only going to be running 11or 12 lbs of boost for a while, al i have is a walbro 190lph, what would one think my max a amount of boost will be on that fuel set up?