Is it the MIVEC or Turbo????
Like a prev member satted. Evolution is to evolve..so the next evo will always be better. No point on trading in your V/// for the IX cuz when the X comes out, most of the IX owners will wanna trade for the new X 
. I just wanna finish paying of my Evo8 get all the power i can afford and see what the Evo will evolve to in the next 5 years. Then start all over again! 
. I just wanna finish paying of my Evo8 get all the power i can afford and see what the Evo will evolve to in the next 5 years. Then start all over again!
Ok, lots of reading coming up. Subaru-centric, but bear with me because it applies here too.
There are a large number of tuners in this country. The number of "good" tuners is fewer. Without naming specifics to the Subaru community, I can say with a great degree of certainty that there are tuners who tune correctly and take advantage of ALL tuning variables and there are those tuning for quick results. Those that take out AVCS on a street car are often uninformed and, to be frank, quite naive. "I don't know what this table does so I'll just zero it out."
There are also some that have a solid understanding of the tables and have chosen to drop AVCS. Those people are ones that have done their research and are aware of the consequences and benefits of doing so. This is typically done for more power than one would need on the street.
Sort of. Just about everything on the Subaru motor is designed for torque, from the intake manifold to the exhaust manifold. If the car is built to take advantage of the mid-range, the need to upgrade cams isn't there until you are driving a racecar. A lot of things have to change before the benefit is really seen. If I were to guess, I'd say cams aren't replaced because they require supporting mods first, whereas an Evo just wakes up with cams.
Going completely off the subject a moment, doing cams doesn't require the engine to be pulled. It is easier, that is for sure. When I can pull a Subaru motor, install a new clutch, and reinstall the motor within 4 hours, using "installation difficulty" as an excuse is a poor one at best.
AVCS originally showed up in the economy cars, just as MIVEC did. The big splash was the JDM STi 2.0L in 2000/2001.
I can't find any AVCS on/off results for the 2.5L (it just worked from the factory), but here is a dyno plot of a 2.0L with AVCS on/off Please note that power was not increased or decreased by any large amount. The onset of torque, however, is to the left by quite a ways.
The problem I am having is, since this was covered in the Subaru world three years ago, all the dyno plots have disappeared from the threads. I've found a few other dyno results, but the graphs are gone. So here is a bit of reading instead:
Apples to oranges, basically. Except I'd like to point out that EcuTek and ProTUNER can both tune high power cars with the factory ECU. There is no lack of EMS systems. The rest of the stuff, well it is just different.
No MIVEC cams yet, as far as I'm aware. Yes, Techtom, EcuTek, Brain, and others undiscovered can or will be able to do MIVEC.
-Jon
quote happy fool tonight
PS: Listen to what SaabTuner has to say. Here is an old post with a triple integral figuring the area under the curve for a cam profile: http://forums.nasioc.com/forums/show...&postcount=100
Originally Posted by Big Boost
One of the things that was very apparant, was that a majority of the Suby tuners did not use the AVCS system to their advantage & most of them simply took it out.
There are also some that have a solid understanding of the tables and have chosen to drop AVCS. Those people are ones that have done their research and are aware of the consequences and benefits of doing so. This is typically done for more power than one would need on the street.
Originally Posted by Big Boost
I know part of the issue, was due to the lack of cams choices, which is changing, but I have not see any specific data to support that a properly tuned AVCS system is helping the 2.5 with lowering the powerband or decreasing spool time.
Going completely off the subject a moment, doing cams doesn't require the engine to be pulled. It is easier, that is for sure. When I can pull a Subaru motor, install a new clutch, and reinstall the motor within 4 hours, using "installation difficulty" as an excuse is a poor one at best.
AVCS originally showed up in the economy cars, just as MIVEC did. The big splash was the JDM STi 2.0L in 2000/2001.
Originally Posted by Subaru STi Technical Document
The purpose of AVCS is the increase engine power and torque output while at the same time gaining improvements in fuel consumption, exhaust emissions and idling stability. By controlling the intake valve timing to suit the engine load and speed conditions this system optimises the engine volumetric efficiency and combustion process.
The problem I am having is, since this was covered in the Subaru world three years ago, all the dyno plots have disappeared from the threads. I've found a few other dyno results, but the graphs are gone. So here is a bit of reading instead:
Originally Posted by AZScoobie
Logs show 15 degrees of advance and it follows the AVCS map inside the ECU exactly ( I can read the rom in live mode). I now get 14 psi at 3700-3900 rpm vs my old logs of 4200-4400 rpm. Header temp greatly effects spool up. I call it minus 400-500 rpm of lag though... Keep in mind that this engine will always be laggy. It has huge ports, no Manifold riser split ports and 258 duration cams with an 8500 rpm rev limit. Its soft down low in comparison to a US engine. Now with the AVCS on its not as painful.
Originally Posted by AZScoobie
The main purpose of AVCS is for low end and high end power as well as mileage and emissions. The top end power increase is because AVCS helps bottom end and midrange so a more agressive Cam can be run. Type RA's come with 258 duration cams. In comparison to the WRX's 218. This is a huge, huge difference in cams.. Without AVCS you would have a lack of low end and a very peaky power band with those cams...
Originally Posted by alfriedesq aka DynoFlash
The avcs just helps spool up - - if you disconect it you get the same peak power
Originally Posted by Pavlo
Faster spool is not the same as more low end torque. Spool up is how fast you can spool the turbo*, torque is just torque. Using the AVCS you can get more torque at lower RPM even if he spool up isn't improved.
One could also say that lower emissions is a byproduct of retarding the cam timing at lower RPM and airflow for better torque. Lower emissions are not caused by better scavenging though, they come from reduced overlap, which in turn helps stop the inlet charge pi55ing out the open exhaust valve.
The nice thing about AVCS is it will give gains off boost, this will generally aid spoolup as you can create more exhaust gas, but with a very large turbo, it probably wont make a huge difference to spool up.
*When you refer to 'spool up' do you mean boost threshold (eg no boost below XXXX rpm) or lag (eg boost delay when already at high RPM)?
One could also say that lower emissions is a byproduct of retarding the cam timing at lower RPM and airflow for better torque. Lower emissions are not caused by better scavenging though, they come from reduced overlap, which in turn helps stop the inlet charge pi55ing out the open exhaust valve.
The nice thing about AVCS is it will give gains off boost, this will generally aid spoolup as you can create more exhaust gas, but with a very large turbo, it probably wont make a huge difference to spool up.
*When you refer to 'spool up' do you mean boost threshold (eg no boost below XXXX rpm) or lag (eg boost delay when already at high RPM)?
Originally Posted by Big Boost
It could also be that with the amount of intercooler/piping needed for a FMIC on a suby, the lack of EMS systems available and the exhaust manifold design, could be hiding the affects on the suby motor.
Originally Posted by Big Boost
It appears that with the 4g63, we may not have those same issues, as cams are arleady available and it appears that the EMS systems should be able to adapt fairly quickly.
-Jon
quote happy fool tonight
PS: Listen to what SaabTuner has to say. Here is an old post with a triple integral figuring the area under the curve for a cam profile: http://forums.nasioc.com/forums/show...&postcount=100
Evolving Member
Joined: Jul 2005
Posts: 274
Likes: 0
From: Davis, California
Originally Posted by Pavlo
Faster spool is not the same as more low end torque. Spool up is how fast you can spool the turbo*, torque is just torque. Using the AVCS you can get more torque at lower RPM even if he spool up isn't improved.
--If you can reach boost at a lower RPM, you have a lower boost threshold and you have more low-end torque. Whereas transient boost response has no effect on overal power; it just dictates the lag time between on/off throttle transitions and varies across all load/RPM ranges.
Lightweight turbine/compressor wheels and shorter pre-turbo exhaust paths typically all help transient response. Twin-scroll turbine housings tend to help both. Variable valve timing, especially in the case of the exhaust cam(s), typically helps boost threshold.
Or at least that's how I understand it.
Evolving Member
Joined: Jul 2005
Posts: 274
Likes: 0
From: Davis, California
Originally Posted by stimpy
PS: Listen to what SaabTuner has to say. Here is an old post with a triple integral figuring the area under the curve for a cam profile: http://forums.nasioc.com/forums/show...&postcount=100
The low lift regions were given the same bias when merely comparing the area, despite that they did not notably contribute to flow. A camshaft with lots of area in low-lift regions will not flow as much as a camshaft with comparably little area in the higher lift regions. So I just went back and found some flowbench data I had for the WRX head and used it to create the appropriate bias by taking the tripple integral.
It still isn't a perfect representation of the flow capabilities of the camshaft/head combination. As an example, two cars with identical camshafts, but with different lobe centerlines, can have dramatically different powerbands. (IE: various MiVEC settings.) This is because of the effects relating to pulsetuning of the intake manifold, the reversion wave in the cyllinder, are the inertia of the intake gasses in the intake port.
Like I said, I was just trying to make it one step more accurate than what Jeff had previously posted. And, though it sounds really complicated, it's nothing extraordinary and I don't think it should do me any credit.
Not sure if anyone said this yet (sorry if I missed this), but a sure way to find out the real IX power "maker" would be to take a stock EVO IX place it on a dyno and tune it for optimal A/F ratios then swap backwards to the VIII 10.5 turbo and tune to the same A/F on that same dyno.
Then simply compare/overlay the numbers from that same dyno and you have the difference in Turbo with MIVEC... That way you would see the reaction of MIVEC to the VIII turbo which is an unknown in placing the IX turbo on an 03-05 VIII car... Currently it seems that we only have IX turbo installs in non-MIVEC cars...
Perhaps MIVEC yields gains in both turbos not seen in non-MIVEC tuning with the VIII turbos or the IX turbo on an VIII…
The data from both VIII->IX turbo and IX->VIII turbo would yield a fairly clear picture of what is doing what...
Hope that made sense in the way I wrote it!
Just an Idea...
I would also love to get my hands on a JDM IX turbo and see what that would do on a US spec Evo IX all other things the same… Are these turbos even attainable?
Then simply compare/overlay the numbers from that same dyno and you have the difference in Turbo with MIVEC... That way you would see the reaction of MIVEC to the VIII turbo which is an unknown in placing the IX turbo on an 03-05 VIII car... Currently it seems that we only have IX turbo installs in non-MIVEC cars...
Perhaps MIVEC yields gains in both turbos not seen in non-MIVEC tuning with the VIII turbos or the IX turbo on an VIII…
The data from both VIII->IX turbo and IX->VIII turbo would yield a fairly clear picture of what is doing what...
Hope that made sense in the way I wrote it!
Just an Idea...
I would also love to get my hands on a JDM IX turbo and see what that would do on a US spec Evo IX all other things the same… Are these turbos even attainable?
this is my opinion <--- lol
the evo8's will do cams and valve spring/retainers to achieve what a evo 9 with STOCK CAMS makes for power, in many cases still not equaling the power of the evo 9's. I believe the turbo makes a slightly significant increase, BUT not nearly as much as the MIVEC does. check out some dyno sheets im sure you can pull them up on here.
also what cdavy said is a great point too.
the evo8's will do cams and valve spring/retainers to achieve what a evo 9 with STOCK CAMS makes for power, in many cases still not equaling the power of the evo 9's. I believe the turbo makes a slightly significant increase, BUT not nearly as much as the MIVEC does. check out some dyno sheets im sure you can pull them up on here.
also what cdavy said is a great point too.
The stock EVO9 cams are practically 264 type grinds, that and the variable lobe location from mivec means more power. The EVO8 and EVO9 turbos have the same turbine sides and the exact same compressor wheels and the same compressor flow.
Anyone without mivec is at a serious disadvantage, it is a real shame that as soon as MMC got it right they stopped making the car.
Anyone without mivec is at a serious disadvantage, it is a real shame that as soon as MMC got it right they stopped making the car.
Thread Starter
Evolved Member
iTrader: (5)
Joined: Aug 2004
Posts: 4,111
Likes: 1
From: Lake Mary,FL
The stock EVO9 cams are practically 264 type grinds, that and the variable lobe location from mivec means more power. The EVO8 and EVO9 turbos have the same turbine sides and the exact same compressor wheels and the same compressor flow.
Anyone without mivec is at a serious disadvantage, it is a real shame that as soon as MMC got it right they stopped making the car.
Anyone without mivec is at a serious disadvantage, it is a real shame that as soon as MMC got it right they stopped making the car.
Last edited by EVIL_EVO_VIII; Dec 6, 2008 at 02:57 PM.
The stock EVO9 cams are practically 264 type grinds, that and the variable lobe location from mivec means more power. The EVO8 and EVO9 turbos have the same turbine sides and the exact same compressor wheels and the same compressor flow.
Anyone without mivec is at a serious disadvantage, it is a real shame that as soon as MMC got it right they stopped making the car.
Anyone without mivec is at a serious disadvantage, it is a real shame that as soon as MMC got it right they stopped making the car.
Try reading what I wrote one more time.
The compressor housing is the ONE thing that is different, and it did not result in any increase to the flow rate of the turbo.
Did ytou seriously think you would catch me being incorrect about a MHI turbocharger?
Thread Starter
Evolved Member
iTrader: (5)
Joined: Aug 2004
Posts: 4,111
Likes: 1
From: Lake Mary,FL
There has been more than a few members on this forum that has swapped out a VIII turbo for a IX turbo on an Evo VIII, and have picked up an additional 25-30whp
I havent seen a Mitsubishi F1 yet either
No offense to our own company.. I love my Mitsu, but the MiVec is junk. Yes its better than nothing but it doesnt seem that great to me. I mean for the autocrosser types, sure... it nice. But for power... no, it will not give you any more peak power, nor hold it any longer. In power cars with thier only goal of making and holding power, are going to use the gearing advance that gives them the most power and holds it the longest. If they dont gain the 20 horses at 3k then so be it... who races at 3k anyways
Again, not trying to be too mean about it but I dont like it. And as for Shiv finding huge power there... whats his fastest Evo? I know Shiv knows alot about the ECUs and such but doesnt seem like he gets into the real power cars much. Hes more of the tinkerer with stockish turbos trying to get that 12hp edge... Id rather get a bigger turbo and get another 100 Even if I only use half its potential I still got his 12 smoked.
No offense to our own company.. I love my Mitsu, but the MiVec is junk. Yes its better than nothing but it doesnt seem that great to me. I mean for the autocrosser types, sure... it nice. But for power... no, it will not give you any more peak power, nor hold it any longer. In power cars with thier only goal of making and holding power, are going to use the gearing advance that gives them the most power and holds it the longest. If they dont gain the 20 horses at 3k then so be it... who races at 3k anyways
Again, not trying to be too mean about it but I dont like it. And as for Shiv finding huge power there... whats his fastest Evo? I know Shiv knows alot about the ECUs and such but doesnt seem like he gets into the real power cars much. Hes more of the tinkerer with stockish turbos trying to get that 12hp edge... Id rather get a bigger turbo and get another 100
Even if I only use half its potential I still got his 12 smoked.http://www.mitsubishi-motors.com/cor...colt_f2000.htm
Eddie Rosado
Last edited by ModenaTwinTurbo; Dec 31, 2008 at 06:05 PM.
