Total timing & AFR

[Phram1]

I am looking for some feed back on what others are running for TOTAL TIMING & AFR at approximately 10lbs - 13lbs and 16lbs boost. Understanding that that total timing and AFR are a little different depending on mods so below lists the bulk of my engine mods-

- JWT S2 cams & springs
- mild porting
- Ross pistons
- GTX3067r turbo
- 3" exhaust
- Maxima plenum
- intercooler

[evildky]

1 degree of retart per lb of boost off your base timing is a good starting point. The target AFR for anything in the positive pressure range should be 11.5 to 12.5 range. You really have to be on a dyno to tune timing properly.

[Phram1]

I recently did some work on the dyno with a focus on timing. The outcome was peak TQ was achieved between 3700 & 4600rpm. AFR in that range was 11.6 - 12.1, boost between 10.5 & 10.8, total timing in that range was 14 to 15. Mild detonation was heard and sensed by the ECM when running 17 to 18 degrees. I received a timing map in 2011 from the owner of the Black b**** on 88hybrid who was running 25 to 26 degrees total timing at those same parameters. That is quite a distance from where I am at. Unfortunately, I have been unsuccessful it reaching him for an answer. I understand that he may have sold the car which may be the reason for no answer.

So, the purpose of this thread it to gather some data and understanding of what others are running. If others are in the same range as BB then i am seeking the reason why.

- 88 VG30ET so compression ratio should 8.3 to 1

[evildky]

What software are you using? Nistune? What values does your software use to generate tuning bins? In MS it's rpm vs map pressure, so we only have half the info. I have a hard time imagining anyone running that much timing in their peak tq range. Lots of timing is used in the lower VE bins to spool up the turbo, timing gets pulled as boost climbs.You need more advance as RPM climbs, but retard as pressure climbs. You got a Dyno graph of yours? His?

[Phram1]

What software are you using? Nistune? What values does your software use to generate tuning bins? In MS it's rpm vs map pressure, so we only have half the info. I have a hard time imagining anyone running that much timing in their peak tq range. Lots of timing is used in the lower VE bins to spool up the turbo, timing gets pulled as boost climbs.You need more advance as RPM climbs, but retard as pressure climbs. You got a Dyno graph of yours? His?

Software - SDS 3m -- tuning bins RPM timing / Map timing - Dyno map below.


I believe the black b**tch has been sold and I haven't been successful in reaching the owner so I do not have his dyno. However, there is a video on Utube about the car.
[youtube]http://www.youtube.com/watch?v=VDb83AuJFWw[/youtube]

My total timing at 10lbs boost-
3000 - 17
3250 - 17
3500 - 17
3750 - 16
4000 - 14
4250 - 14
4500 - 14
4750 - 14
5000 - 15
5250 - 17
5500 - 20
5750 - 23
5750 - 23

[Phram1]

I don't think the dyno sheet posted properly. I will try again.

[evildky]

I would fatten the fuel at your peak torque enough that you don't have to retard the timing in that range, or lean out the range above so that the timing is more consistent, your timing shouldn't dip. That dyno map I guess is yours, no O2 or boost overlay? Most shops can add wideband and boost for just a few bucks more. Where you hit your peak tq, there is a large plateau, are you at 10 psi at that point? Are you pig rich at that point? I wouldn't worry so much about your vs his unless you have an actual graph to overlay, too many variables, altitude, air density and then the engine and drivetrain and dyno variables. But with that plateau if you are floating 10 psi whats the map look like at 16 psi? That turbo is about the same size as stock, the Bb center section should make for faster spool but it's still gonna max out around 300-350 whp tops and thats at 16-18 psi.

[G-E]

Simple answer is a gt35 flows a lot more air a lot more easily than a gt30, so the gt35 isn't heating the air as much, and allows for increased timing...

I would suggest flattening out your map at boost to be really rich and safe timing, get back on the dyno and tune it line by line, setting the boost controller higher each time you're happy

It seems like you know what you're doing, so it shouldn't take you long

[Phram1]

According to the Garrett's compressor map for the gt35, the sweet spot is about 19 lbs and the gtx3067r is around 16lbs. It is unlikely that I would want to run that much 19lbs.

I have all my runs and on my computer an will post a more complete map with AFR and boost in the next day or so. 10lbs is reached at about 3000rpm and the AFR is running in the mid 11's during peak torque.

[evildky]

It's a bit more complicated than a simple psi sweet spot, it's a matter of having the "knee" point at or near peak efficiency as well as the max air flow. It's a matter of what you want, the smaller turbo will spool faster but will not flow as much air as a larger turbo, 10 psi at 30 lbs/min is less than 10 psi at 50 lbs/min, thats the part most people don't get. That being said if your max hp goals are in the 300 whp range and you want something that spools fast then you made the correct choice. If you want 400whp, this turbo isn't going to get you there, no matter the boost, it simply can't move that much air.

[Phram1]

I understand and I agree about the proper turbo for my goals. My ride is a daily driver and my hp goals are right in the mid 300's. For me it is not about high hp it is about good hp and longevity of the motor. To many of my friends have the 'turn it up' mentality and I find them cleaning up their ambitions with a mop and bucket.

That said, I continue to look for some points of reference on other tunes with similar mods that might help guide me along my journey. I have found the information you've given me thus far to be helpful in further tuning the ride. The 14 - 15 degree of total timing at 11.6 - 12.1, seems low for running 10.5lbs of boost so you may understand my quest for knowledge.

I have attached a photo of the motor review.

[Phram1]

I have attached a more dyno run with hp - tq / boost / AFR.

[G-E]

Why is your afr so lumpy? It almost looks like there's o2 feedback screwing with it, that or you keep running into knock and the ecu is retarding timing ?

[Phram1]

The bumps are a bit of a challenge be as the EMS system I am using is a SDS EM 4. SDS uses a 2 dimensional fuel map vs 3-5 dimension map on other newer EMS. In addition, the RPM values can only be change at 250RPM increments. To clarify, if I am running 100 units of fuel at 10lbs boost then that 100 units is applied to every RPM value. A 3 dimension system would allow me to change the unit of fuel for each boost / rpm cell without effecting the units of fuel globally at a given boost pressure.

The EMS is almost 15 year old and Does have limitations. I am looking to upgrade my EMS to a Link g4 or a vipec i44 in the near future and this issue will be no longer. That said, the bumps reflect a .1 - .4 fluctuation in the AFR on the average which pretty good for this EMS. I must say I have seen far worse.

[Phram1]

I have a posting of a dyno graph from the z31 I mention in previous replies who is using the same SDS EM4 system as I am using. He was showing off the gains by switching his T4 to a GT35 but the point I was making about the AFR can be seen on his graph as well. Rather bumpy.

[evildky]

Actually it would be an SDS EM4 6F as you are running it on a 6 cylinder engine and you are not using the distributor. I haven't looked into SDS since I learned about megasquirt years ago, at the time SDS was the hot ticket for fast L28ET's. It appears you have a whole lot of 1 dimensional tuning. You set your base line rmp based fuel and timing maps, then you have a row of MAP based timing and fuel adjustments which does not allow for much fine tuning or resolution. Have you adjusted your map timing adjustments at all yet?

Why did you go with the SDS? I didn't realize Satan was running sds on BB, I guess I assumed he was running nistune or some romulator. I did MSNS on my Z31 but for a fresh build i'd go nistune.

[Phram1]

You are correct, SDS EM4 6F.

MAP timing - Yes. I have established an RPM timing and map timing values can be adjusted up or down. For example, at 3000rpm the RPM timing is 32, then at 10lbs boost it pulls 15 degrees out leaving a total timing value of 17. In turn, if I am traveling down the free way at 13 in vacuum then I have set it to add 13 to the mix so I am running 45 degree total timing.

Why SDS, because in 2001, this set up was recommended by a local tuner and I knew very little about the world of EMS. Now 13 years later, I am far more educated it is time to make a move. First step, change out my T3/T4 journal bearing turbo to a GTX3067R dual ceramic ball bearing turbo, this was a great move. Now the next step new EMS. But till this comes about, I am looking to further refine the existing system. Hence the reason for this thread.

Thank you for the Nistune recommendation. And now you know more.

[evildky]

So is there a timing dip in your base timing? Or is it due to the map adjustments? Your AFR is a bit lean across the board, I'd fatten the map based enrichment, and or fatten the fuel value in that rpm base map, it's at an rpm where you're full boost so it might not hurt to be a little rich especially if it allows you to add some more timing.

[Phram1]

I have continued to fine tune the AFR's after the Mar. 13 dyno work represented in the dyno sheet in my previous post. You will find my base timing and current AFR based off the SDS data logger below.
Base timing Current AFR
2000 - 31 12.4
2250 - 31 12.3
2500 - 32 12.8
2750 - 32 12.8
3000 - 32 12.3
3250 - 32 12.1
3500 - 32 12.1
3750 - 31 12.0
4000 - 29 12.4 Goal - AFR 11.7
4250 - 29 12.4 Goal - AFR 11.7
4500 - 29 11.8 Goal - AFR 11.7
4750 - 29 12.1 Goal - AFR 11.7
5000 - 30 11.8
5250 - 32 11.2 Goal - AFR 11.8
5500 - 35 11.2 Goal - AFR 12.1
5750 - 38 11.3 Goal - AFR 12.1
6000 - 38 11.3

What are your thoughts about the timing, current AFR and Goal AFR? Once I am close then I will work on the timing on the dyno.

[Phram1]

I forgot to mention the big challenge in hitting these goals, which I believe you would understand, is the conditions of the day. Barametric / Air Temp / etc but I will try.

[G-E]

I'm still thinking your timing is the problem, it affects apparent afr too making you appear richer when really you're just too retarded..

Unless you're trying to overcome a sudden hump in load ramp like on a vtec car, your map should be fairly smooth for timing, ie. it should trend up or trend down, not wobble up and down

Whats your timing map look like or do you only have boost retard?

[Phram1]

Base timing can only be adjusted by MAP timing.