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Old 04-08-2008, 02:02 AM   #401
NSFW
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Quote:
Originally Posted by AZScoobie View Post
For example. On Nasioc, people always seem to think the .63AR turbine housing will help spool on 30R and 35R turbos. As you can see by the maps listed on turbobygarrett this is not going to work.
How do you translate from a point on the turbine map to a point on the compressor map?

Thanks.
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Old 04-08-2008, 09:18 AM   #402
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Quote:
Originally Posted by AZScoobie View Post
I have tested some of the worst bolt on turbos imaginable. Most popular bolt on turbos wont have enough turbine flow as most use the common 8cm housing. At 20 psi I have seen some nearly 70 psi on the turbine side. To make matters worse they use the 2.4 inch stock inlet diameter. I have measured 5 to 7 psi of vac on the inlet!

Did you mean that most common bolt on turbos use the 7cm housing which causes a lot of EGBP?

This weekend I tuned my ej207/20g setup. This is a TD06H-20g 8cm^2, 3" inlet. I was actually able to advance the intake cam at redline and make power which I attributed to the lack of backpressure.

Spool was okay- I ended up with 350 ft/lbs at just over 4000 RPM (the spoolup AFRs were a little out of whack which I will fix on the street) and that should help there, But on that motor, I was making 375 hp at ~7000RPM and still making 350+ hp at 8500 RPM.
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Old 04-11-2008, 04:26 AM   #403
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Old 04-21-2008, 01:49 AM   #404
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Quote:
Originally Posted by crazymikie View Post
Did you mean that most common bolt on turbos use the 7cm housing which causes a lot of EGBP?

This weekend I tuned my ej207/20g setup. This is a TD06H-20g 8cm^2, 3" inlet. I was actually able to advance the intake cam at redline and make power which I attributed to the lack of backpressure.

Spool was okay- I ended up with 350 ft/lbs at just over 4000 RPM (the spoolup AFRs were a little out of whack which I will fix on the street) and that should help there, But on that motor, I was making 375 hp at ~7000RPM and still making 350+ hp at 8500 RPM.
Good deal man. Sounds like a nice setup. You are correct that the increased intake cam timing was the correct thing to do in this situation. Your EGP is LOW with that turbo on the 2.0 engine. But only up to a point in boost pressure. You might find that you will have to retune the Cam map if you go to higher boost pressures. You might be able to fine tune the top end even more if you dare. But sounds like you got great top end power which not many subaru engines and or tuners can, or no how to do.

On the bottom end. Remember. Never tune or boost pressure or spool up. Always tune for power. I see alot of people/tuners make mistakes saying that they got XX turbo to spool up at XXXX RPM! Guess what spools a turbo? Lots of hot and rich unburnt fuel! Tune for power down low and when you cant make more you got it. I frankly dont care when the engine hits a bar boost. I care that it makes more power downlow and runs efficient.

Clark
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Old 04-21-2008, 03:12 AM   #405
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Hi Clark, can you answer the question I asked a few messages ago, in #401?

Thanks!
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Old 04-21-2008, 10:10 AM   #406
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Thanks. The car feels like a beast on the road- I have more than enough usable power and the car feels responsive, so that is probably more important. I'm guessing the number of times I'm going to be flooring the car at 2500 RPM is going to be limited anyway.

I am pretty sure the topend is maxxed out- I spent a good amount of time experimenting, and I think there's not much left to get up there. I think upping the nitro concentration a little bit in the mix may yield some more gains (I'm at 7% now, so I might try 8% next batch). I am currently at ~30 psi peak, down to 25 psi at redline. You can feel the difference between 28 and 30 psi quite a bit. Intercooler outlet temps are 5 degrees C above ambient at the top of a 3rd gear pull (100+ mph), so I don't think the turbo is overworking at all. I was honestly surprised to find it was making power at those boost levels. I do need to find an EBC now since the stock ECU doesn't really do a good job with boost that high.

I also left some power on the table on the bottom end- adding a degree of timing yielded ~10whp, so I know I still have some headway there. I'm just scared for the well being of my 5 speed tranny.

I can't wait to get her up to the track. The Miatas may take me in the turns, but I think I'll have a bit of an advantage on the straights



Quote:
Originally Posted by AZScoobie View Post
Good deal man. Sounds like a nice setup. You are correct that the increased intake cam timing was the correct thing to do in this situation. Your EGP is LOW with that turbo on the 2.0 engine. But only up to a point in boost pressure. You might find that you will have to retune the Cam map if you go to higher boost pressures. You might be able to fine tune the top end even more if you dare. But sounds like you got great top end power which not many subaru engines and or tuners can, or no how to do.

On the bottom end. Remember. Never tune or boost pressure or spool up. Always tune for power. I see alot of people/tuners make mistakes saying that they got XX turbo to spool up at XXXX RPM! Guess what spools a turbo? Lots of hot and rich unburnt fuel! Tune for power down low and when you cant make more you got it. I frankly dont care when the engine hits a bar boost. I care that it makes more power downlow and runs efficient.

Clark
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Old 04-21-2008, 11:15 AM   #407
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wow, your car sounds scary just by reading this!


what do you guys recomend using for Cosworth AVCS cams? (going in MY04 Type RA with HKS twin scroll)

the specs are

Int 278 Degree, 10.74mm Lift
Exh 274 Degree, 10.0mm Lift

compared to stock

Int 240 Degree, 8.9mm Lift
Exh 240 Degree, 9.5mm Lift


I couldn't find much data on how much you can advance those, but what do you think would be a good starting point, 25*? Stockers run @ 45
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Old 04-21-2008, 01:06 PM   #408
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Quote:
Originally Posted by NSFW View Post
Hi Clark, can you answer the question I asked a few messages ago, in #401?

Thanks!
I did not understand what you are asking extactly. Please explain.

Clark
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Old 04-21-2008, 01:11 PM   #409
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Quote:
Originally Posted by crazymikie View Post
Thanks. The car feels like a beast on the road- I have more than enough usable power and the car feels responsive, so that is probably more important. I'm guessing the number of times I'm going to be flooring the car at 2500 RPM is going to be limited anyway.

I am pretty sure the topend is maxxed out- I spent a good amount of time experimenting, and I think there's not much left to get up there. I think upping the nitro concentration a little bit in the mix may yield some more gains (I'm at 7% now, so I might try 8% next batch). I am currently at ~30 psi peak, down to 25 psi at redline. You can feel the difference between 28 and 30 psi quite a bit. Intercooler outlet temps are 5 degrees C above ambient at the top of a 3rd gear pull (100+ mph), so I don't think the turbo is overworking at all. I was honestly surprised to find it was making power at those boost levels. I do need to find an EBC now since the stock ECU doesn't really do a good job with boost that high.

I also left some power on the table on the bottom end- adding a degree of timing yielded ~10whp, so I know I still have some headway there. I'm just scared for the well being of my 5 speed tranny.

I can't wait to get her up to the track. The Miatas may take me in the turns, but I think I'll have a bit of an advantage on the straights

Just make sure you have a real good EGT gauge installed in the ports. You need to keep an eye on things if you plan to road race that thing at those boost pressures. Thats ALOT of boost for extended use. I would lower it to 24 to 25 psi

The next step is to install a boost gauge in the upipe with a fitting and stainless leader hose. This way we can map the turbine pressure and you can further map the cams.

Cya

CLark
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Old 04-22-2008, 01:16 AM   #410
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I found an indirect way to calculate EGBP. You can calculate rate of change of boost by going 0-WOT at different rpms in the highest gear possible. You do have to overshoot by a few psi to get an accurate reading around your target boost. You can probably find a pressure ratio if you can follow the turbine and compressor map, but it's really unnecessary. On my avo380 setup, EGBP climbs rapidly near 4000 rpm. After some testing I discovered that EGBP is low enough up to about 3500 for advanced AVCS. Basically it follows follows the inverse of the "EGBP" curve through the high-load range. Of course this was a "duh" moment because the avo380 gets creep around this area if you're not running > 20psi already.
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Old 05-03-2008, 03:22 AM   #411
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have an adm 02 sti and after 4000rpm the cams were dropping out. This issue is now fixed, but i have found that i now have to remap the avc-r duty. as the boost i was running, 23psi dropping to 21 at redline on a vf34-P20 is now like 18-15psi. i have pretty much maxxed out the duty after 5500rpm to try to run the boost i am after. i also already have a 15psi wastegate installed on the IHI.

is their a relationship between avc-s being advanced, and having to run more wastegate duty for X amount of boost?


edit:
ignor my ignorance..
throttle body to silicone was leaking under boost.

Last edited by vaccine; 05-03-2008 at 03:56 AM.
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Old 05-04-2008, 09:31 PM   #412
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Glad you found your problem. It is harder to make boost as the cams are dialed towards 0. On my car I get a huge drop in boost when the cams roll off. This is normal.

Clark
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Old 05-16-2008, 07:06 PM   #413
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Here's my own GT30 AVCS map. Hope it helps others move in the right direction since no one else seems to be willing to post maps.


Some parts of the map I've purposely smoothed out due to speed density, like near idle. I wouldn't worry about that area too much.

This is the result of trying to maximize VE and also back off due to hesitation in certain areas.
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Old 05-16-2008, 07:39 PM   #414
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here's mine:

v7 ej207, handported heads, td06h-20g, 8cm^2, water/meth/nitromethane.

running about ~30psi peak to ~25 at redline (8500rpm)

attn noobs: if your car assplode from using this, i ain't responsible

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Old 05-17-2008, 07:06 AM   #415
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thanks for posting those up, guys.

i'd post mine but they're stuck at 0.
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Old 06-02-2008, 10:53 AM   #416
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Subscribed!
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Old 06-02-2008, 01:52 PM   #417
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I have the Autronic also. Will try this!



Quote:
Originally Posted by STI8U View Post
I just got my car back today, after it was found my so called AVCS aftermarket cams were actually non-AVCS cams. Anyway, the cams have been fixed and are now moving as expected.

I haven't had a chance to do detailed analysis, but what I found was quite interesting. The car has been tuned with the cams at a fully retarded position of ~130 crankshaft degrees (as reported by the camshaft position sensor).

I chucked in 110 degrees (~20 degrees advance) across the entire map (I have Autronic EM) and this is what happened:

1. Car was running much leaner - hitting peak boost the car was running 11.5:1 AFR with cams at 130 degrees. With the cams at 110 degrees, car was running 13.5:1 AFR - didn't let it rev past 4000RPM for fear of blowing the engine.

2. Turbo spooled up faster - previously hitting 15PSI @ 3600RPM in 3rd, now hitting 15PSI @ 3200RPM in 3rd. How lean the car was running probably aided the spool up time.

What I believe this shows is with 110 degrees advance, at the RPM range I looked at (2000-4000RPM), the engine was flowing significantly more air, hence this level of advance is much more optimum for that range.

An idea I now have for tuning AVCS without a dyno is:

1. Set AVCS map to 0 advance. Tune fuel map rich - e.g. 10.5:1 for high load sites.
2. Set AVCS map to 5 advance. Do a few power runs, log AFRs
3. Set AVCS map to 10 advance. Do a few power runs, log AFRs
4. Set AVCS map to 20 advance. Do a few power runs, log AFRs
5. Set AVCS map to 30 advance. Do a few power runs, log AFRs

Once you are done, compare the AFRs at various RPMs. The leaner the AFRs become relative to your first run the more optimal (since the fuel map is constant for each run, the AFR reading shows how much more/less air is going into the engine). Doing the base run rich is to avoid running too lean during your testing. Running it at 10.5:1 allows for you to detect if the engine runs richer (most wideband AFRs lose resolution below 10:1).

The above technique I believe should work with a MAP-based engine management system (like Autronic or Motec), not sure on a MAF-based system as load is expressed in air mass. On a MAF-based system it might be as simple as looking at the MAF readings for each different level of advance but it's kinda chicken in egg.
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Old 06-03-2008, 11:37 AM   #418
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Good day, can someone explain how you adjust AVCS on the Autronic SM4? I was looking at it and I see variable valve control, but not sure what is supposed to be adjusted.
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Old 06-07-2008, 03:39 PM   #419
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Quote:
Originally Posted by Freon View Post
Here's my own GT30 AVCS map. Hope it helps others move in the right direction since no one else seems to be willing to post maps.


Some parts of the map I've purposely smoothed out due to speed density, like near idle. I wouldn't worry about that area too much.

This is the result of trying to maximize VE and also back off due to hesitation in certain areas.
I'm gonna test out this map, since I have an SR55 which is about the same size as the GT30. I'll let you know if the car feels any different, and if it does if it feels better or worse.
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Old 06-07-2008, 08:58 PM   #420
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Quote:
Originally Posted by Freon View Post
Here's my own GT30 AVCS map. Hope it helps others move in the right direction since no one else seems to be willing to post maps.


Some parts of the map I've purposely smoothed out due to speed density, like near idle. I wouldn't worry about that area too much.

This is the result of trying to maximize VE and also back off due to hesitation in certain areas.
That looks very similiar to the map I made for my sz55, looks like I did things right although I have mine at more of a slope up.
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Old 06-08-2008, 10:17 AM   #421
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Quote:
Originally Posted by STI8U View Post
Here's some test data I collected...

What I did was set timing to 12 degrees fixed and then set the AVCS advance to 0 degrees advance, 10, 20, 30 and 40 degrees and captured injector time and AFR (via wideband AFR).

This allowed me to calculate cylinder load at each given data capture point (the total mass of air in all cylinders at the point of capture), which is simply based upon the injector time at each data capture point and the measured AFR at the data capture point. I have assumed my injectors flow 565cc/min and that fuel has a mass of 0.76g/cc. This calculated engine load is directly proportional to mass air flow.

Here are the results (note that I stopped the 30 degree and 40 degree runs early as I know that much advance isn't very good at high RPMs):

Mass Air Flow


Measured AFRs


The differences are interesting. In theory, the mass air flow graph should be what you work from, but the 20 degree advance result is somewhat misleading at high RPMs. The mass air flow graph indicates 20 degrees advance is better at high RPMs than 0 degrees advance - this is definitely not the case, based upon seat of pants and the fact the car is running about 2PSI more boost with 20 degrees advance at high RPM, indicating the engine is more restricted.

Based upon the mass air flow graph, these would be the optimal AVCS settings (assuming your map uses 250RPM increments:

4000RPM: 40 degrees advance
4250RPM: 30 degrees advance
5000RPM: 20 degrees advance
5750RPM: 10 degrees advance

Based upon the AFR graph, these would be the optimal AVCS settings (assuming your map uses 250RPM increments:

4000RPM: 40 degrees advance
4750RPM: 30 degrees advance
5500RPM: 20 degrees advance
6500RPM: 10 degrees advance
7500RPM: 0 degrees advance

Next time I'm on a dyno I'll repeat this exercise and see which of the above (calculated mass air flow or AFR) is more aligned with power output...

Interesting! Good work!
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Old 06-08-2008, 10:41 AM   #422
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Quote:
Originally Posted by AZScoobie View Post
Your new Cam map has some serious flaws in it. I guess with more experience you will realize this. The biggest flaw is that you have changed the cruise and part throttle Cam advance. Now mileage will suffer a great deal as will emisions and response. Those load rows are very light. You are adding alot of cam where its not needed. Again. More testing of adding cam in and not retuning the timing and AFR maps. Remember. The only volume knob for power is boost. There is only one correct timing setting. It must be found. AFR has a larger span and other reasons to consider. In cyl cooling and egt control as well as a knock buffer. I dont know any other way to say what I said without sounding like a jerk... Sorry.

Like other maps in the ecu each car will have a different optimal cam map. what works on a VF39 wont work well at all on a 35R. I just got back from Minnisota where I tuned 14 cars. One was a JDM 2.0 spec C motor. That car picked up huge with a remap of the cams. I wish I would have printed the plots. It came in at 250whp on a super low reading dyno dynamics at 25 psi. I retuned it at 20 psi and it pulled 320whp. I wont disclose the original tuner. No point to flame. But he had the absolute wrong cam map and timing map in that ecu. A stock sti makes under 200whp on this dyno for example.

I just wish I had control of the exhaust cams. Some huge top end could be gained.

Clark
Wow, I have the S202. I want those gains. Clark, are you familiar with Autronic?
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Old 08-19-2008, 06:01 PM   #423
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Hey guys, before I go back and read all the posts, let me just ask a simple question.

I was protuned and noticed that the tuner didn't touch the AVCS map. It's completely stock. So I was thinking of playing with the MAP a bit to see if I can add some advance and help spool.

Of course I'll take little increments, but how does adding advance alter the tune. Does it make the AFRs richer, leaner, or doesn't affect them at all? What other things does adding advance affect?

Thanks and sorry for the noob question
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Old 08-19-2008, 07:35 PM   #424
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Please spend a little time to review the whole thread. It is very interesting.
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Old 08-19-2008, 07:55 PM   #425
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Please dont just add or remove advance to the cam map. You will have to retune the timing and AFR

Clark
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