neffster

iTrader: (2)

From Paranormals Blown motor post, Mike at Altered Atmosphere stated... Well how do I find out how much timing has been removed from my Vortech tune and what is the right amount? I don't have data logging capabilities and this morning the temperatures were about 40 degrees colder than when I initially tuned my car.

On the way into work the temp gauge pegged 51 degrees the whole way and I thought I'd do a little experimenting. I carefully and curiously decided to take a gander at the a/f gauge to see what types of deltas I would see from 3000rpms to near redline (under WOT) and I was a little surprised at what I saw.

Previously I would hit a/f #'s in the 11.2-10.6 range at WOT in 3rd gear and now I'm seeing 11.6-11.2 with a slight dip right into the 11.0-10.8 right at redline.

The odd thing is that the numbers are staying right around 11.4 pretty consistantly (with a few flashes of 11.6 and 11.2 scattered around) from 3k to about 6k rpms and the numbers used to be quite a bit lower. It was very common for me to see 10.X after 4500 rpms and now I'm about 0.5 a/f higher.

I don't know if this is a big deal, but am more concerned as to what's going to happen when the temps hit the low 30's or high 20's. How does timing play into all of this? Does anyone on here have this ECU Stabilization Upgrade and can they explain how it works? If I get the ECU stabilization upgrade would I need to get a retune? Which map would be the map that TS copies or do they just give the ECU a "standard" map that I would need to get retuned? TIA

Brando

You worry too much.......lol

Did you email this info / question to your / our tuner???

Tantrum Z33

iTrader: (27)

"The factory ECU has very high timing and this is not ideal for forced induction. Additionally, there are several timing maps in the factory ECU. We have found that when the 350Z&G35 is on the dyno it commonly runs from the main timing map. The downside is that the factory computer can advance the timing, which is a major contributor to engine failure."

Since the factory ECU has 3 maps, the ECU will tend to switch over to a advance timing map when the weather gets colder. You would have to speak to your tuner to make sure theres enough timing pulled for the upcoming colder temperatures so when the ECU switches over to the advance timing map, you will have enough timing retard to compensate for the advance timing. Or, you can get a ECU reflash from AAM or technosquare to reflash the ECU to run only one timing map all the time.

GurgenPB

iTrader: (2)

ECU does have 2 maps, but the switch over between the two is not directly rompted by a temp change, but by knock feedback. The ECU monitors knock, and picks the saefst map that it can to have the least 'starting' advance, and it retards from there. For air temperature, there is a separate map, like there is in all other OE ECU's, for IAT compensation (just like there are tables for coolant temp, battery voltage, fuel temperature, etc. compensation). the problem is that we don't know where any of these tables are.

Neff...you are running the split second box, correct? i'll follow up with the rest of my answer after your reply.

g8tor20

Hey Gurgen....to help speed up your response (as I am interested as well)...yes...Neff is indeed running the SS box.

theking

iTrader: (3)

If you want to stabilize your tune just send your ECU to TS and have them flash the same program in both the maps. Since you are already tuned to the less advanced map then you know you will get the same total timing no matter what the stock ecu tries to do.

GurgenPB

iTrader: (2)

OK...Well first of let me say that hte ECU has 3 maps (not 2, which is what I typed above), but two of those maps are identical (one has knock feedback, the other doesn't). So in effect, there are two different maps...

Nonetheless, what I was going to say is that if you are using the SS box (or any other) with MAP-based tuning, a chaneg in intake temperature will very well introduce the change that you encountered. It's pretty straighforward, as cooler air is denser than hotter air; while this is obvious, that's not all there is to it. In your case, the centrifugal SC compresses the air a certain amount, relative to rpm. The resulting pressure, i.e. boost, is a result of temperature and mass of air. When the intake temperatures go down, given that there is no closed-loop boost control like there is with turbo, the SC is likely to develop slightly less boost because the temperature is now lower (and hence contributes less to the final "pressure" - which is BTW inconsequential, all that you should be after is increasing mass). As this is taking place, your SS box is reading a lower boost prssure frame in its table, and applies less fuel (as it should have ONLY IF the temperatures were to remain constant). But the amount of air that you ingested is roughly the same (only the resulting pressure went down from llower IAT), resulting in leaner mixtures.

So how do you correct this.... well this is exactly why all OEM (and race car) setups that use MAP-tuning, also use the obligatory IAT compensation...the two together make the 'speed density' tunign possible. You need BOTH pieces of data to accurately deduce "n" (number of moles of gas), or mass of gas. Or, on the other hand, just use a MAF sensor drectly (now you can see why the OE's transitionedto MAF....far more accurate and consistent).

Hope that was helpful.

neffster

iTrader: (2)

To be totally honest that was both helpful and a little confusing... I guess what I should have asked is that if I'm pulling enough timing (I'm looking into this now) and my A/F #'s stay in the mid 11's when the temps get nice and cool will I should be safe?

Is that over simplifying things too much?

Alan, BTW "you’re heinous"; (nice play on words, no? ) I'd like to keep away from TS if at all possible for the time being. I'm very leery of anyone touching my ECU when my car is 3000 miles away, regardless of the circumstances. Also, how does TS know which map to copy to the other? Would I need to re-tune after this reflash? What if they copied the wrong map?

Before anyone gets upset at me, Alan and I are buds and I’m just having fun with “The King” and his screen name.

GurgenPB

iTrader: (2)

11.6 is a good AFR to work with. I was just giving you an explanation why your AFR got leaner. The correct algorithm for tuning cars (assuming it is low enough, "correct" compression) is to set a safe timing advance, normalize your AFR...go as lean as your cylinder head temps will allow (F1 cars in the age of 70psi turbos ran 12.5-13 AFR, but of course they rebuild the engine after the race), normally 12-12.2:1 (again this assuming you have a low comrpession engine - like 8.5-9:1), then set the timing as close as possible to the position which yields peak cylinder pressures at 14-17degATDC without knocking. If oyu don't knock and achieve this position, that's how much its humanly possible to extract out of that engine.

As far as stock engines are concerned....the high static compression ratio is going to require combustion chamber cooling (i.e. running richer AFRs, or water injection, which is 6 times the latent heat of gasoline and hence suprior knock suppression .. although that's not the water's only role). Hence, you cannot run the optimal 12-12.4 AFR, instead power-robbing mid-low 11's will have to be used.

overZealous1

iTrader: (27)

gurgen, you know how much difference is in between the maps as far as timing is concerned. i could not imagine it to be much, but enough if you were close to begin with. do you feel the intake air temp map in the eu could effectively be a safeguard in the event of the stock ecu hitting the advanced map? or is it too unpredictable as far as when it may switch to that timing map? so just richen below 70degrees or so progresively (or whatever temp the car was tuned at)?

GurgenPB

iTrader: (2)

The difference is significant. An example...right after flashing the car, I went ot for a ride and got a near-lethal 25degree advance.. After a few minutes of drvign, it went down to 19 (all passed 5200 rpm, where the knock regionstops0.

That's why I have a custom flash, where all three maps are flashed to one identical map... copied and pasted. But I am not sure TS will allow you to do that.

booger

iTrader: (6)

One time [ I have not logged much ] I seen my timing go from 22 degree's advance to 24 degree's after 65000rpm at wot . Because of this, I will not try for huge numbers when tuning the car until I get a engine managment that can hold the timing where you set it .

theking

iTrader: (3)

This is not necessarily a bad thing. Your timing "should" be retarded the most at peak torque and then advance toward redline. This is why most tuners reguard an EGT gauge(along with a WB) as a good tool to dial in the advance towards redline. Assuming all things being equal(AF ratio, intake temp, coolant temp. cylinder wall temp) an EGT gauge will tell you if you are retarding timing too much from peak torque on. Once your AF and timing are set at the rpm the engine hits peak torque(no knock and max torque) you can then monitor the EGT's as the car goes towards redline and add in timing until you have knock, lose torque or have too high of EGT's. This is way oversimplifying things but hopefully you got my illustration. This is why you see pyrometers on each cylinder for many race engines. This gives you a better idea of what each cylinder desires as far as timing and fuel. Again I am oversimplifying things and I do not pretend to be a good tuner but I know the general concept.

booger

iTrader: (6)

Ya..I kinda understand that part..adding timing back as you get closer to red line . But what if you are doing it and the ECU is doing it also ? You then have twice the advance than planned and it gets dangerous

theking

iTrader: (3)

This is why a base flash to have the same timing on all maps and then applying an ignition offset to it is a good idea. You won't have to "try and hit a moving target" in reguards to the timing. Setting static timing is ideal and that is why alot of us are drooling over the UTEC(or the EU once static timing is able to be set and not just an offset).

CpraceZ

iTrader: (3)

Eric is going to get you all the information you asked for today, honestly your a/fs look fine 11.5 is not to lean we tune these cars with a little safety cushion because we know a lot of our customers are from out of town FL, VA, GA, and even further we know the weather is not always going to be the same in one place as the other, we have a greater drop in temp here in NC then in FL and have never had a problem with weather change making any 350z that we have tuned dangerous in anyway.

Sharif@Forged

iTrader: (92)

IMHO, I think the concept of ECU timing map swapping is being taken out of context. The stock ECU is NOT going to run precisely the same timing on every single pull. The ECU takes inputs from a myriad of sensors, before timing the motor at a given point. 25 degrees of "stock" timing is not bad at redline, as long as its being dialed back with the engine management system...which is what the tuner will do. The ECU, under full boost and WOT, is never going to suddenly advance the timing to 30+ degrees. I have logged over 300 runs with the EU on various cars, and have never seen any ignition spikes...just normal acceleration.

Oftentimes, when people are logging timing with a fast scanning device, they see this acceleration of ignition advance towards redline. For instance...from 21 degrees to 28 degrees as redline approaches...and then panic sets in. This is a totally normal timing curve for an NA car. The slope of the timing curve is nearly identical for FI...but you dial it back...starting from a lower base. Absolute timing MUST advance towards redline, as the piston is moving faster, and the AF charge needs to start burning a little sooner, to reach peak cylinder pressure at about 14 degrees after TDC

Neff....CP tunes their cars pretty conservatively when it comes to timing and AF...seen this many times before. Timing-wise, I wouldnt worry at all...especially since the Vortech produces much less trq than the turbo systems. High TRQ, and the TRQ peak, are areas were detonation is most likely to occur. In regards to your fuel, just keep an eye on it. Temps have dropped in Charlotte from about 80 last week, to 50 this week, and my AF hasnt moved at all. Of course, there will be minor variances between runs....both nothing meaningful.

neffster

iTrader: (2)

Thanks for the replies everyone. This morning I made sure to really get on it from 1st through 4th gear and I definitely saw 10.8 right at redline in every gear, it was just a little more lean around the 4000-5500rpm range.

Hopefully it is clear that I'm just fishing for information and trying to understand how this system actually works rather than complaining about an installer/tuner (hope that wasn't implied)...

Eric Oram from CP Racing told me they're pulling 6 degrees of timing on my car and is supposed to be sending me a detailed spreadsheet of my runs. I had a copy of this around here somewhere... if I can find it I'll post it for everyone to look over. Overall I'm super happy with this set up and haven't had one problem. The car seems to be pulling MUCH harder with the colder temps and I'm very satisfied!!!

Thanks again for the comments.

Mr_pharmD

iTrader: (48)

10.8 is really rich don't u think? I would think the injector seals would go bad and u would smell gas.

I always thought FI hp/tq were best seen with an A/F of 11.8-12.0, therefore your car should feel a lot faster in colder temps if your a/f ratio gets close to 12.

neffster

iTrader: (2)

That's a question best left to my tuner/installer. CPRace, care to comment?