|
|
|
|
Thread Tools | Display Modes |
11-04-2007, 06:41 PM | #301 |
Scooby Specialist
Member#: 55854
Join Date: Feb 2004
Location: Central FL
Vehicle:2004 STi Blue/silver |
I was looking over some compressor maps a while back and found that a case could theoretically be made for advancing AVCS at the top end, depending on the turbo and engine combination. Whether or not I'll ever have the opportunity to test things out on a dyno is doubtful. My thinking could be way off base (not the first time).
* Registered users of the site do not see these ads.
|
11-04-2007, 06:48 PM | #302 |
Scooby Specialist
Member#: 53451
Join Date: Jan 2004
Location: Caribbean
Vehicle:2000 JDM Impreza SRX w/ AVCS Silver |
Ok. When on that note, what you can do it take it with step, tuning avcs, fuel and timing within that particular range.
Example, 1000rpm ranges after that point. If you have access to a dyno, that would be great, but if not, reviewing the VE can help. The only problem is the environment that is not controlled. We look forward to your results and success. Last edited by west_minist; 11-04-2007 at 07:15 PM. |
11-04-2007, 06:59 PM | #303 |
Scooby Specialist
Member#: 56321
Join Date: Mar 2004
Chapter/Region:
NESIC
Location: Hopkinton, MA
Vehicle:2006 Honda El Camino Green |
I don't think there is a set rule to always taper by a given RPM. It doesn't make sense.
Here's my understanding of how it works, hopefully, it will give you some direction in things to try. It's kind of a cliff's notes for this thread...... Advancing the intake cam will effectively raise the compression of the motor, however, as backpressure increases, the mixture in the cylinder becomes contaminated with recycled exhaust as opposed to fresh air. Backpressure depends largely on the turbo, specifically the hotside size. A different header could also affect things if it is better-designed than the stocker. In any case, the more you relieve backpressure at the exhaust port, the more you will be able to take advantage of adjusting the intake cam. Running a 35r with a 1.06 hotside should flow very well and allow for advancing the cam later in the RPM range. On the contrary, a stock turbo will become a restriction and advancing the intake cam will not yield any benefit. I haven't been able to play with different cams, however, different cam efficiency will play into whether or not advancing the intake cam will yield any good results. I am guessing this has to play into Jay's findings. Remember since you are affecting the efficiency of the motor, you may need to change AFRs and timing to optimize the new settings. For example, if you can make the same power by changing AVCS but removing a few degrees of timing, you are on the right track since you've improved the VE of the motor. If you were to draw out the 4 stages of a combustion motor, it might make more sense. Think about what happens as the stages get faster and faster. Hope that helps. Again, this is what I've come to understand and it seems to work for me. Mike |
11-05-2007, 01:53 AM | #304 |
RIP 10/12/83 to 02/10/08
Scooby Specialist Member#: 83254
Join Date: Mar 2005
Chapter/Region:
NWIC
Location: Roy, Washington
Vehicle:98 2.5 RS 04 WRX |
^^^This actually tracks well with what I've started seeing on the dyno since tuning on one. The AVCS for a VF39 is far different than for a FP Red, or even a TD04 for that matter. Seeing a bigger torque plateau and a bit more peak torque makes people happy thats for sure. Haven't had too much time to play with AVCS yet, takes too long to tweak without realtime tuning when you've got 2 hours to finish a tune.
|
11-05-2007, 07:47 AM | #305 |
Scooby Specialist
Member#: 56321
Join Date: Mar 2004
Chapter/Region:
NESIC
Location: Hopkinton, MA
Vehicle:2006 Honda El Camino Green |
My header cracked [again] but I have provisions for a backpressure gauage now. I'm going to see if I can find an electronic sender than can handle enough heat and pressure so that I can log backpressure in the uppipe and relate it to manifold pressure. That should give me a big hint in how to map AVCS. Once I get the header situation resolved, I can get back to tuning.
|
11-05-2007, 09:09 AM | #306 |
Scooby Specialist
Member#: 78165
Join Date: Dec 2004
Chapter/Region:
South East
Location: SC
Vehicle:05 STI 35r + e85 |
Here is my present AVCS map. Important mods are a .82ar gt35r and cosworth 278/274 avcs cams.
Lately I've been playing with AVCS advance under light throttle / low load. Advance in the 0.85-1.15 load area has a nice effect on responsiveness (i.e. the turbo is spooling as soon as you lean into the throttle). |
11-05-2007, 09:30 AM | #307 |
Scooby Specialist
Member#: 56321
Join Date: Mar 2004
Chapter/Region:
NESIC
Location: Hopkinton, MA
Vehicle:2006 Honda El Camino Green |
Jay,
What happened when you added advance after the turbo spooled up? Did you boost increase? Did your load decrease? Thanks, Mike |
11-05-2007, 09:34 AM | #308 |
Scooby Specialist
Member#: 78165
Join Date: Dec 2004
Chapter/Region:
South East
Location: SC
Vehicle:05 STI 35r + e85 |
Boost goes down, but I only tried adding AVCS under boost up till about 6k rpms. I pulled out AVCS in that region and bam, overboost.
|
11-05-2007, 09:41 AM | #309 | |
Scooby Specialist
Member#: 56321
Join Date: Mar 2004
Chapter/Region:
NESIC
Location: Hopkinton, MA
Vehicle:2006 Honda El Camino Green |
Quote:
Boost is a measure of restriction, and by advancing the cam, it's quite possible you are allowing the engine to breathe better and make power more efficiently. Mike |
|
11-05-2007, 03:33 PM | #310 |
Scooby Specialist
Member#: 88322
Join Date: Jun 2005
Chapter/Region:
MWSOC
Location: Indianapolis, IN
Vehicle:2009 BMW 135i |
I agree with what crazy mikie has posted with regards to backpressure. I generally only get away with adding a bit of advance at lower rpm on stock turbo cars, and relax timing at the same load/rpm. I can get away running way lean on my own GT30 .82 at low rpm with lots of advance, I can run 14.0:1 up to 4-5 psi no problem (no knock), but that doesn't work on smaller turbo cars, which will exhibit hesitation if they're run too lean or with too much advance. Running that lean seems to hurt torque a lot even though it does move boost threshold down. Overall my own car is running just a butt load more advance overall than I seem to be able to get away with a larger bolt on, say, like an FP Green 8cm IW. It's probably +8-10 CA more from 2800 to 5500. Granted, I've had far more time to mess with my own car as well, and I've spent more time actually attempting to run more advance while avoiding the hesistation/misfire behavior that seems to accompany running too much cam advance in the lower ranges.
In upper ranges, like 6000+, running more advance seems to hurt airflow and require more WGDC to maintain boost. I've made no attempts to run extra advance above the range where I find I'm moving back to zero. I guess the trend could reverse itself, but it doesn't seem to make sense that it would. I'll probably post some maps later. I'm very interested to pick up a EL header and see how it affects what I can get away with. I want to get one for next season. |
11-05-2007, 05:05 PM | #311 | |
Scooby Specialist
Member#: 56321
Join Date: Mar 2004
Chapter/Region:
NESIC
Location: Hopkinton, MA
Vehicle:2006 Honda El Camino Green |
Quote:
|
|
11-05-2007, 07:24 PM | #312 |
Scooby Specialist
Member#: 88322
Join Date: Jun 2005
Chapter/Region:
MWSOC
Location: Indianapolis, IN
Vehicle:2009 BMW 135i |
Eh, yeah I think you're right. I'll go back and look at the logs.
Anyway, here's my suggestion to start with for a basic stage 2 car compared to stock: Last edited by Freon; 12-31-2014 at 03:10 AM. |
11-05-2007, 07:42 PM | #313 |
Scooby Specialist
Member#: 56321
Join Date: Mar 2004
Chapter/Region:
NESIC
Location: Hopkinton, MA
Vehicle:2006 Honda El Camino Green |
I'll try to get some logs up this week too- I have an interesting combination (ej207 with td06h-20g 8cm^2). The hotside of that turbo is relatively large so it will be interesting to see what I can do in the upper ranges.
|
11-06-2007, 03:11 PM | #314 | |
Scooby Guru
Member#: 8785
Join Date: Jul 2001
Chapter/Region:
SWIC
Vehicle:02 c_turner@ix. netcom.com |
If I posted my AVCS maps for each bolt on and rotated turbo the next day ever single tuner out there would copy and paste them into the maps. I help just about every tuner out there as it is now and I have trained more then 50% of them in person. I continue to help armchair tuners and even Book smart NO EXPERIENCE engineer types as a service to this community.
That being said I am always glad to help and you can always ask questions. But my AVCS map that makes 20whp more then anyone in the biz will not be posted. Sorry. I spent years fine tuning it. Clark Quote:
|
|
11-06-2007, 09:27 PM | #315 |
Scooby Newbie
Member#: 13626
Join Date: Dec 2001
Chapter/Region:
MAIC
Location: Maryland
Vehicle:02 996 |
I would love to see a dyno comparison of a protuned car before and after the AZScoobie AVCS maps (with that being the only change between runs). 20whp is a pretty bold statement.
Not saying it's impossible, but plenty of other tuners have also spent considerable time experimenting with, learning, and improving the avcs values. BTW, what's your rate for helping armchair tuners over email? We definitely appreciate the help you've given us thus far in this thread alone. |
11-06-2007, 10:22 PM | #316 |
Scooby Guru
Member#: 8785
Join Date: Jul 2001
Chapter/Region:
SWIC
Vehicle:02 c_turner@ix. netcom.com |
I dont charge anything for help man. I get 2 to 5 emails a day with dyno plots and logs. I always respond with advice. It may work or it may not. I am here for this community. Ask away. I might know the answer or I might not. I have the lux of having alot of experience that might be helpfull.
C |
11-06-2007, 10:30 PM | #317 |
Scooby Specialist
Member#: 11218
Join Date: Oct 2001
Chapter/Region:
SCIC
Location: Mission Viejo, CA
Vehicle:2005 Legacy GT Wagon |
Me too! It would help me justify using STi heads w/ AVCS when I put a 2.5L in my 02 wagon instead of using stock WRX heads. I will be going to Clark for a tune when the time comes.
|
11-07-2007, 02:02 PM | #318 |
Scooby Specialist
Member#: 88322
Join Date: Jun 2005
Chapter/Region:
MWSOC
Location: Indianapolis, IN
Vehicle:2009 BMW 135i |
Eh, ignore that errant 1.0 at 7600rpm... It should be zero.
|
11-07-2007, 02:13 PM | #319 |
Scooby Specialist
Member#: 78165
Join Date: Dec 2004
Chapter/Region:
South East
Location: SC
Vehicle:05 STI 35r + e85 |
I was gonna say, that 1 degree at 7600 must be helping a lot
|
11-07-2007, 09:47 PM | #320 |
Scooby Specialist
Member#: 56468
Join Date: Mar 2004
Chapter/Region:
NWIC
Location: Seattle, WA
Vehicle:04 Improved STI Dirty White |
After playing with AVCS for awhile I only see improvements in the mid torque range (yes it could be 20 hp there) and with boost onset (picked up about 200 RPMs with more aggressive advance on a GT65). One has to be careful not to induce knock with the increase in dynamic compression at low RPM. Bigger cams help on the top end, but I've not more with intake advance at high RPM.
|
11-07-2007, 11:52 PM | #321 |
*** Banned ***
Member#: 16200
Join Date: Mar 2002
Vehicle:OK buy Nates beans westcoastroasting.com |
...after having played with this for a while, now......I think 20whp across the midrange is well within reason for optimized AVCS.....my car with the stock turbo seems to pull pretty well....
....much to the consternation of some of the locals |
11-08-2007, 02:59 AM | #322 |
RIP 10/12/83 to 02/10/08
Scooby Specialist Member#: 83254
Join Date: Mar 2005
Chapter/Region:
NWIC
Location: Roy, Washington
Vehicle:98 2.5 RS 04 WRX |
So what do you guys think of this one, and Clark I want your opinion too
This is NOT my map by the way, this is by a open source tuner who works at a shop that has also created the ugliest ignition timing table I've ever seen as well (25 degrees of timing at idle? Why not?) Anyway this is supposed to be from a Stage 2 STI with upgraded TMIC running 22 psi of boost. IMO there is way too much advanced here, in my experience on the dyno so far adding any AVCS after 5200 has hurt power/torque and had a noticeable increase in EGT. There might be some thing to adding a bit over 5200 with the right timing and fuel if I had enough time to play around with it, but this map just looks crazy. |
11-08-2007, 10:17 AM | #323 |
Scooby Specialist
Member#: 56321
Join Date: Mar 2004
Chapter/Region:
NESIC
Location: Hopkinton, MA
Vehicle:2006 Honda El Camino Green |
The scaling in the last few columns is funny.
I've had similar experiences to you- advancing the intake cam on that small turbo doesn't really help at higher RPM. I've never been able to try it on a dyno, but all of the logging on the street I've seen points to less power. |
11-08-2007, 12:09 PM | #324 |
Scooby Newbie
Member#: 10884
Join Date: Oct 2001
Chapter/Region:
NESIC
Location: MRV, VT
Vehicle:2008 Impreza |
I am currently trying to sort knock issues that may or may not be related to AVCS tuning. I would like to get a few more eyes looking at my problem.
My set up is: 02 WRX V7 EJ207 W/ECU and AVCS Everything else is stock USDM WRX (Turbo/Injectors/Intercooler) Catless UP/DP The AVCS map that I have been running was a stock JDM WRX 2.0 map. I have been getting knock only in 5th gear from 2500 rpm up to about 3000 rpms in the 1.3 - 2.3 load range. I can see boost any where from 7-18 psi in this range but the knock has been independent of any particular manifold pressure. My timing is pretty low in this area and AFR's are in the 11.5:1 range. I pulled a couple of degrees of advance out of the map and flattened out a spot in the problem area but this didn't help a whole lot. It actually seemed to result in boost spiking, so I need drop my WGDC's even further, this engine can spool the TD04 ridiculously fast. At this point I am not really sure what to do or if this AVCS map is way off. |
11-08-2007, 12:53 PM | #325 |
Scooby Specialist
Member#: 103320
Join Date: Dec 2005
Location: Oklahoma City
Vehicle:1998 swapped Forester L |
aren't the EJ207s usually designed for the Japan 96 octane? The AVCS could be an indicator.
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Let's talk hybrid economy / performance tuning | Bad Noodle | Open Source Reflashes | 17 | 04-29-2012 09:30 PM |
Let's talk flywheels | WRXThis | Transmission (AT/MT) & Driveline | 9 | 04-17-2002 02:04 PM |
Let's talk about when to change out the rods. | Andrew | Normally Aspirated with bolt-on Forced Induction Powertrain | 10 | 03-04-2002 11:44 AM |
Let's talk amps.... | Teh Legacy | Car Audio, Video & Security | 15 | 10-19-2001 02:09 AM |
Let's talk about the Rimmer Supercharger | rao | General Forum Archive | 88 | 09-21-2000 07:56 AM |