Questions about new mods

I am starting this thread seperate from my "Slow Boy Racing Nightmare" thread, in case that one gets locked. Hopefully not, as I tried to be as factual in my post as possible. But, anyway, on to the questions:

Mods are in my sig, so I won't bother repeating them. Only weird thing about my car is the stock cat back (and don't even start on that :grinno: )

1. Why does it take so much longer for the car to fire after it sits. Did Walboro forget to put a check valve in their FP, or is mine just fucked up?

2. My car was "supposidly" tuned with a wideband O2 to an AFR of 11.3 on 94 octane at 17.5 lbs of boost. How is this possible with a WBO2 that gets shoved in the tail pipe (after my Hi-Flow Cat). Isn't the cats "job" to regulate the gasses expelled from the system, thereby keeping the O2 voltage constant?

3. Does the fact that they beat the shit out of my front O2 cause any problems with the WBO2 tuning? Or is it just that they had no way to set my FT's?

4. Why, if my car was tuned with a WBO2 are my SAFC-II settings so freaking funky. I know it will be hard to tell without a log, but I am waiting until I get the O2 from the dealer and the FT's straightened to start beating on the car.

Settings (performed by SBR with WBO2 Tuning)

Ne Points - Correction (Hi throttle table)

1000 rpm - 23
2000 rpm - 23
3000 rpm - 22
4000 rpm - 36
4600 rpm - 27
5000 rpm - 34
5400 rpm - 33
6000 rpm - 33
7000 rpm - 33
7200 rpm - 33
7400 rpm - 33
7600 rpm - 33

The low throttle is -27% across all the Ne-Points.

5. During the one run I did get (up to 5500 rpm) my logger showed max airflow of 20.54 lbs/min at 17.5psi. Assuming that occurred at 5400 rpm and a correction factor of -33% airflow, the actual airflow would be 27.31 lbs/min. Shit, my t-25 was flowing about 25 lbs/min at 15 psi.

6. Why the hell are my dyno numbers so low....I'm almost embarrased to tell you guy. Fuck it.....241.5 WHP and 232.4 Lb * Ft

Thanks!

Be sure to check out my other thread if you need something to read for the next 25 minutes :iceslolan

http://www.automotiveforums.com/vbulletin/showthread.php?t=428502

1 - Its possible that its leaking down at the point where the pump attaches to the in tank assembly. I never had trouble with that, but I have heard of it happening enough times to suggest it. WBO2s in the tailpipe are the most common way to take the measurement on dynos. I'm sure the cat has some small effect on the readings, but its always done this way.

3 - I would not expect them to have set the fuel trims. That takes a good deal of time at idle and at steady state cruise to get that done. You should be able to do that going forward. It has no effect on WOT tuning.

4 - Its not uncommon to see settings like that. That 36 looks like it may have been meant to be a 26. Hard to say without seeing the AFR trace on the dyno sheet. But again, FTs have nothing to do with WOT performance. -27s are a little low (rich) for 650s, but it all depends on what your trims look like. I would expect to be around -31%, but it does vary from car to car.

5 - 5500 rpm is too low to take an airflow reading. With stock cams and intake it will peak between 6000 and 6500 rpm. At 15 psi I would not expect to see much of an airflow difference anyway, especially since the T25 has just started to fall off at 5500. Bigger turbos are installed because you can raise boost and get more flow. Not because they will get more flow at the same psi (this is rarely the case at low boost).

6- hard to say. The SMIC is not helping you at all. Relatively low boost is also not a good way to make power. Not enough data available to make an accurate determination.

Hope something here helps.

SMIC is reaching its limits at 240 hp...frontmount or big SM time. And hate to start on it...but catback is restricting mucho flow. With that, more/better tuning you can run 22psi on some decent gas. Those numbers aren't that bad for 17psi..but more tuning..and less dickhead shop guys. BTW ECU works off airflow when under WOT, no o2 sensor feedback modifying the trims.

1 - Its possible that its leaking down at the point where the pump attaches to the in tank assembly. I never had trouble with that, but I have heard of it happening enough times to suggest it.


So, the problem I am having is not normal for the FP? What do I look for if I pull the pump?


4 - Its not uncommon to see settings like that. That 36 looks like it may have been meant to be a 26. Hard to say without seeing the AFR trace on the dyno sheet.


They gave me a copy of the dyno sheet, but it is unlike the others I have seen on tooners and talk. There is no WB trace on the bottom below the power/torque curve. I was only told what their target AFR was (11.3).



Bigger turbos are installed because you can raise boost and get more flow. Not because they will get more flow at the same psi (this is rarely the case at low boost).


Now that I have the LICP securly attached, I will go out and make a pull tonight and see what the timing curve and airflow looks like.


Relatively low boost is also not a good way to make power. Not enough data available to make an accurate determination.


I guess once I get a log posted up it will be much easier to get an idea of what is going on. Maybe, if I'm lucky, I'll be able to bump up the boost a couple of psi :smile:


Hope something here helps.


Yes it did, thanks for your time! :biggrin:

Hard to accurately blame your problem on the pump without a guel pressure guage. What you describe could be cause by fuel pressure leak down, but it could also be caused by other things. Many times cars that have fuel pressure leakdown will still start right away, since the pump builds pressure as soon as you turn the key. Hard to say without more data :)

Not all dynos print the AFR trace. I have never used a dynapack, but the dynodynamics doesnt print either. You can however get the AFR and boost trace on a seperate sheet. I would have asked if its possible to get that info.

I'm curious to see how the log looks.

Many times cars that have fuel pressure leakdown will still start right away, since the pump builds pressure as soon as you turn the key.


When you turn the key to the ON position, is the pump supposed to start running before you actually start the car?

Mine does not, but I have been in other cars that do. I couldn't tell you if the stock one began running, as it was silent.

no, pump shouldent run until car is running.

Neither of you are entirely correct. The pump doesnt come on with the key on our cars, but it can't exactly come on after the car is running either ;)

On these cars as soon as the CAS moves, the pump comes on. It builds pressure very quickly though from what I have seen.

I'm curious to see how the log looks.


I finally got around to logging a pull. This is a 3rd gear pull from 2k to redline. For being tuned with a WBO2 it doesn't look very good. They said it was tuned for an AFR of 11.3:1.

http://files.automotiveforums.com/gallery/watermark.php?file=/503/155962EVO_III_Log.JPG

I think Kevin was right about my 4k Ne point, it looks like it should be 26 instead of 36.

Here is what I think I should do....

Add fuel at the following Ne points 4.6k, 5k, 6k, 7k. I was also thinking of changing some of the Ne points as it seems they are being wasted at 7.2k, 7.4k, 7.6k.

Here are my questions.

1. Do you guys agree with adding fuel at those points.

2. Should I remove the 7.2 and 7.4 Ne points and if so, where should I use them? I was thinking of using 2 of them at 3.5k and 6.5k. That would give me Ne points of 1k, 2k, 3k, 3.5k, 4k, 4.6k, 5k, 5.5k, 6.5k, 7k and 7.6k.

3. Why is my airflow so low? It peaks at 19.82 lbs/min as seen by the ECU at 6760rpm. With the correction factor that's 26.36 of true airflow. This is 1.33g/rev at the ECU and 1.77g/rev of unadjusted airflow. My T-25 was flowing 25.45lbs/min at 15psi. The boost on the EVO III is set at 17.5psi. The only difference seems to be that the EVO III pulls through the entire rpm range and doesn't fall on it's face like the T-25 did.

I installed the new O2 sensor last night and made another pull. The O2 was 0.96v through the entire pull.

I also set the FT's.....this is really weird but I ended up having to set them around -12 to -16. 650cc injectors should be around -31%. Is there any way to tell if they really installed 650's?

Thanks!

You're running really rich! Something isnt right with the AFC settings. They should be atleast -30% for it to even run right. Being at -12% is rich as hell and I am surpised your car even runs. Do a boost leak check just to make sure you dont have one. That could also cause a problem!

You're running really rich! Something isnt right with the AFC settings. They should be atleast -30% for it to even run right. Being at -12% is rich as hell and I am surpised your car even runs. Do a boost leak check just to make sure you dont have one. That could also cause a problem!


Yeah, as weird as it sounds it idles/cruises just fine, just like stock.

My Hi-throttle table is in the mid 20's and it looks like i'm running a little rich there also (O2 at .96 - .98).

I just wasn't sure why my trims would be dead on at -12% and the mid 20's would be fine for the hi throttle. I just installed a new O2 yesterday.

Many things affect trims besides your AF settings. PCV valve, VC vents, MAS issues, intake leaks, etc. With the info available it is impossible to tell what it is.

Timing in the log looks fine as an absolute value, but considering that it should be shooting for over 20 degrees at your post AFC airflow/rev level, it must be getting some knock.

I tell you, I don't know how the fuck I used to tune this way... :D Might have been better to spend some of your money on a WBO2...

As far as airflow, I think I may have said earlier that I wouldnt expect a large gain at the same boost at such a low boost. At 17 psi on a well setup car without cams I would expect about 33 lbs/min. With some of the bottle necks you have I might expect around 30. In fact, with the 2g on the stock exhaust and IC I couldnt get over 30 lbs/min no matter how high I went with boost (up to ~23 psi). Looking at the log of the 2g at 15 psi on my site I was at 29 lbs/min at 15 psi.

Hold on, I need to run some numbers here... SOmething isnt making sense.

Airflow is at 19.8s at 6xxx rpm. Corrections at 6k and 7k are 33% according to the original post. You must be adding in the 33% incorrectly. You are multiplying by 1.33 to get the 26.36 figure. The number you see in the log already reflects the 33% reduction, so you can't use that number to add 33%. Instead, divide the 19.82 by 1 - .33, or .66. That gives you 30.03 lbs/min. To verify this is correct if you dont take my word for it, multpily both numbers by .66 ( or subtract 33%, same thing) and see which one gives you the 19.82 you logged. The 30 pound figure will.

Ok, now that thats out of the way, what is airflow/rev now... 2.06 g/rev at 6500 roughly. So close to the 2.1 g/rev cutoff. Peak timing should be 17 degrees over 2.1. The extra you get is from being just below 2.1. Above and below the 6500 airflow will be lower, and timing will then be higher. Nice curve. Your log actually shows your car holding airflow very well on the top end ofr a stock cam stock IM setup. Plug those numbers into excel and graph it, and you'll see the same airflow curve you would see in something like DSMlink.

So it looks knock free. This is good news ;)

To get back on the airflow per boost thing, 30 lbs at 17 psi makes more sense than 26. Thats what I was getting at 15 psi. Any more boost it wouldnt go up presumably because of the stock exhaust. I would lower your boost to 15 psi and see what happens. If airflow stays about the same, you are experiencing the same thing. That extra 2 psi will be just cause more heat. To max out the turbo you'll obviously need to improve airflow:boost ratio, but it would go against your specific requirements for exhaust and the like IIRC.

Hopefully this makes some sense. I didnt go back and clean it up, I'm hoping that leaving my "thinking out loud" post the way it is will provide some insight to the way I approach these problems. Hope it helps!

I'm an idiot! I didn't even think about the correction that way.

Good catch!!! You get an "AttaBoy" for that one.

So you don't think that turning up the boost 1psi more would give me the extra airflow to reach 2.1g/rev and drop me back to a normal airflow map? Or wouldn't that work because the airflow is measured before it's compressed by the turbo.
This is where I get confused :confused:.

I was hoping that you would tell me to bump up the boost a couple of psi :naughty:

I will take your advice and drop the boost back to 15psi and see where I end up.

Thanks Kevin!

Try going both ways (boost that is)... If it still increases as expected with boost, then you can go higher. As long as you are over 2.1 g/rev timing will make sense. Wait a minute though, it needs to be over 2.1 at the ECU, or 3.1 at the MAS (2.1/.66). That may be hard to do. Lets see. 2.1 grams is .00463 pounds. At 6500 rpm you would need 30 lbs/min at the ECU (.00463 * 6500), or about 45 lbs/min for real (30/.66). Probably not going to happen. I may have made this mistake above, not coverting back to what the ECU sees. If you can get to 33 lbs/min for example, you would still only be at 1.5 g/rev at the ECU at 6500. Not sure what the timing is "supposed" to be at that level, so it will be hard to tell if its knocking.

I hope this illustrates how larger injectors have more of an effect on timing! What a pain in the ass. :)

I hope this illustrates how larger injectors have more of an effect on timing! What a pain in the ass. :)


Yep, you've got that one right!

I just wish I would find an EPROM ECU under my pillow on of these days. :p