RRE RalliArt Build -Baseline Testing and Tuning

[MikeW-RRE]

We had our car from South Coast Mitsubishi for a short two weeks to build. Our concept was to find the most bang for the buck mods, something the average guy would want to do while staying within a budget but get some real performance that he could feel.

The first thing we did was to do a baseline dyno test on it to see what we had to work with. What you see here is three back to back dyno pulls on our Dynapack DP6000 AWD dyno. I allowed coolant temperature to stabilize at 82 c between each run. Still you can see big variances between the runs as it warms up overall under the hood. The first run is red, second is green, last run is blue. A little heat in the motor is good. More.. well not too much. I called it a 210 hp average.


http://www.roadraceengineering.com/ralliart/dynos/rre/ralliart-baseline.jpg


Stock factory boost is also very low. The little turbo is already building 5 psi at 2,000 rpm and hits peak boost before 3,000 rpm. But then it is a down hill rollercoaster ride from there on. It eventually falls to a low of 8 psi :-P

http://www.roadraceengineering.com/ralliart/dynos/rre/ralliart-baseline-boost.jpg


Air fuel ratio was predictably rich too. You can see in the second (green) run where for what ever reason the car was not so rich for a little bit around 5k. That is where the second run got is HP bump.


http://www.roadraceengineering.com/ralliart/dynos/rre/ralliart-baseline-afr.jpg


Mike W

[MikeW-RRE]

For fun I tried a couple drop in filters. These cars use the same drop in panel filter as the EVO X and I had a K&N and a HKS filter to tryout. Well… save your money for something else for now. They made no measurable difference on this stock car. On the EVO X we see 20-30 hp from the way they lean things out. The air swirls into the air box differently with different filters and hits the air flow meter in different ways. On an EVO X this leans it out big and helps a ton. This car nothing with both filters.


http://www.roadraceengineering.com/ralliart/dynos/rre/ralliart-filtertest.jpg


http://www.roadraceengineering.com/ralliart/dynos/rre/ralliart-filtertest-boost.jpg


Each set of three runs has a high, low and medium pull all pretty much averaging the same. I could have cherry picked the lowest stock run and the highest drop in filter run and shown a 10 hp gain. But sooner or later these kind of shenanigans fall apart.


Mike W

[MikeW-RRE]

So I got started tuning on it with it all stock still. Stock filter, I/C and pipes, stock cat and exhaust. This car has a small turbo! Boost really drops off pretty much whatever you ask of the wastegate. Using the stock wastegate hoses I was able to get boost to rise to 22.5 psi at 3,000 rpm and finish at 12.5 psi. I messed with ignition advance and the MIVEC settings along with leaning out the air fuel ratio and got another 30 safe and smooth horsepower.

http://www.roadraceengineering.com/ralliart/dynos/rre/stock-tuned-241hp.jpg

http://www.roadraceengineering.com/ralliart/dynos/rre/stock-tuned-241hp-boost.jpg


Dyno time and the tuning for this car runs $500 using ECUFlash.


Mike W

[laflsyl10]

Nice, a lot of good information on here..
I'm just wondering what the difference between a blow of valve is and a wastegate...

[drmosh]

Hey Mike,

The car drove really good out on the course. Had ample power for such a short course.

Kudos.

[CarGuy]

For a review of how this car ran...see the front page news story about the Mitsubishi Super Stores Customer Appreciation Event! Let's just say it was impressive, very impressive!

[MikeW-RRE]

The wastegate is a valve inside the exhaust housing of the turbo. It is controlled by pressure from the intercooler piping. When the pressure in the intercooler piping gets high enough, it pushes a rod that is hooked to an arm. The arm connects to a valve inside the turbine housing of the turbo. When the valve opens, it allows the exhaust pressure to bypass the turbine wheel. This means less exhaust pressure to spin the turbo. The turbo speed and therefore the boost pressure is regulated by the wastegate and the rest of the boost control system.

Internal wastegate valve open:

http://www.roadraceengineering.com/eclipsetech/porting/wastegate-alignmentoff.jpg

Internal wastegate closed:

http://www.roadraceengineering.com/eclipsetech/porting/wastegate-marked2.jpg


An aftermarket external wastegate is used with large turbos. You will usually find it hanging off the exhaust manifold. Larger wastegates don't make more power. They allow you to keep control of the turbo speed of a big turbo better:

http://www.roadraceengineering.com/parts/wastegates/tial-36mminstalledon2gmanifold.jpg



A Blow Off Valve, Compressor Bypass Valve for your purposes are essentially the same thing. When you are mashing on the throttle, the turbo is pumping air at full force. The throttle is open, the engine is taking all the air in that it can. Everything is good. When you let off the throttle, everything stops dead. The turbo gets bogged down trying to pump the air into a closed throttle plate. The air has nowhere to go and tries to go back out the turbo as the turbo is trying to pump more. The turbo gets slowed down in addition to all kind of bad forces acting on the compressor wheel.

So starting in the early 80s manufacturers started putting a valve that would open when there is a certain level of vacuum in the intake manifold. The valve opens when you let off the gas allowing the turbo to kind of freewheel. This maintains the turbo speed better so that you have more boost when you get back on the throttle.


This is going to come up so I might as well answer it here:


The Holy Grail of anyone under 25 years old with a turbo car is to have this excess pressure release heard by other kids under 25 years old. High school boys are particularly impressed by this PH-Shhhhh sound. Word is that their high school girlfriends will leave them and come and jump into your car. Cools stuff indeed.

You can spend time and money trying to achieve this sound by taking off the factory BOV and replacing it with an aftermarket one. The aftermarket one will need to blow the air out so that it can be heard by the high school boys. You just cap off the hose where it was blowing back into the turbo inlet pipe.

On Mitsubishis this creates several issues. The ECU has seen all the air enter the system since it was measured by the air flow meter. The ECU gives you the right amount of fuel for all this air. If you blow a grip of air out for the high schools boys to hear, the ECU has no idea you blew it all out. It still gives you fuel for the air you let out. The car goes rich and almost stalls or bucks. The high school girls do indeed get wet though. It is a trade off like all things in life.

The answer is to tighten the aftermarket BOV so it does not blow off as much air so that the motor stalls. Now you hear this turkey gobble noise like “cha-chooo-chooo-chooo”. Think any HKS BOV you have heard. That is the sound of compressor surge destroying the turbo. Congratulations! ;-)

But sp4rkl3bunn3y on the forums says he runs his car blowing out and it does not stall. Well sp4rkl3bunn3y has a stock turbo running low boost and the little compressor surge he gets isn’t going to hurt much for now. He thinks the compressor surge sound he is hearing is a cool BOV noise. Higher boost and a real man sized turbo will make it undriveable.

Also on your RalliArts the way that the tranny is always up shifting and the ECU has more control over the throttle than you do I doubt you would hear much.

With the Mitsubishi drive by wire system there are a bunch more checks and balances with what air flow the air flow meter should be seeing at any given RPM and throttle position. I have seen so many EVO X guys fight SES lights and limp modes with various aftermarket BOVs. It is just another big mess to deal with. Even if you are recirculating the air back in, if the BOV is looser or tighter and allows different than expected air flow past the air flow meter, it is just misery.


Stock Blow Off Valve/Compressor Bypass Valve

http://www.roadraceengineering.com/ralliart/tech/bov-stock.jpg

I was looking at the stock BOV and saw that it was plastic. I thought that it might leak under higher pressure. I noticed that a stock EVO X BOV would bolt right on! SWEET!

But I looked inside the two BOVs and saw that they both had an o-ring seal on the valve seat. I tested the spring pressure and they are both the same. Changing this stock plastic BOV on the stock turbo will not make any power gain. If you will be running over 30 psi someday, then think about changing the BOV. Otherwise a different BOV is for nothing other than vanity or headaches.

Mike W

[CarGuy]

Now, that was funny! I never had a turbo car in high school...maybe I would have gotten lucky more often if I did. lol

Great job explaining that Mike!

[MTZL]

Now, that was funny! I never had a turbo car in high school...maybe I would have gotten lucky more often if I did. lol

Great job explaining that Mike!

I didnt even have a car in High School, wasnt fortunate enough. Dropped out of high school and got a job than I bought my first POS 89 Honda Prelude which I had to tap the starter to get started. Previously salvaged, lol

First new car was my 00 Honda Civic over 5yrs of payments and 200,000 miles later, blown engine. I replaced it with K20 all motor and $,$$$ after it got no a/c, no power steering, Axle is not right length, CV boot spitting grease. Need Chamber correction. and blah blah but it can outrun an old porche 911.

09 GG Lancer Ralliart is My first turbo AWD. Plan to keep it stock unless performance parts/upgrade got bullet proof or unconditional warrenty. lol

I learned my lesson the hard way with my hard earned money.
Do not upgrade without research!

Great info Mike W RRE, this might be the only upgrade I'll get once I have the money to burn.

So I got started tuning on it with it all stock still. Stock filter, I/C and pipes, stock cat and exhaust. This car has a small turbo! Boost really drops off pretty much whatever you ask of the wastegate. Using the stock wastegate hoses I was able to get boost to rise to 22.5 psi at 3,000 rpm and finish at 12.5 psi. I messed with ignition advance and the MIVEC settings along with leaning out the air fuel ratio and got another 30 safe and smooth horsepower.

Does this save gas? Better gas mileage? I know performance car is not econo car. 30 safe and smooth horsepower sounds great!

[MikeW-RRE]

By running the car leaner in theory you would get better gas mileage... under full throttle. Typically a turbo car on a race track gets between 5 and 7 miles per gallon. So bringing that up to 6-8 MPG yes that would be an improvement :-P

In reality a tune like this would cause you to burn much more gas (as much as your drivers license point allow anyways). You will be having so much fun with your right foot firmly planted to the floor you wont care though.

The best way to stretch a tank of gas is to stay out of boost altogether.

Mike W

[coolguy949]

Great work Mike! Bolt up an Evo X turbo on it next time and lets kick some Evo tail on the course! :)

See ya at MOD.

[Ladogaboy]

I'm surprised that the drop in filters didn't flow better. Would a tune + drop in make any difference here?

Also, is this a case where a short ram might be the right choice? I wouldn't want one without a tune though. :(

[MikeW-RRE]

The RalliArt is using the same stock filter which flows fine for well over 250 WHP on an EVO X. I think it just isnt the restriction holding things back on the RalliArt. This stock filter is huge. Trust me, I would have loved to sell you all drop in filters if I could have proved they made measureable power.

I wil be testing an Injen intake shortly.

Mike W

[Ladogaboy]

The RalliArt is using the same stock filter which flows fine for well over 250 WHP on an EVO X. I think it just isnt the restriction holding things back on the RalliArt. This stock filter is huge. Trust me, I would have loved to sell you all drop in filters if I could have proved they made measureable power.

I wil be testing an Injen intake shortly.

Mike W

Yeah, that makes sense. So it looks as though the major power bottleneck for the RA is the turbo.

[CarGuy]

Yeah, that makes sense. So it looks as though the major power bottleneck for the RA is the turbo.

I'm guessing since he replaced the lower intercooler hose and intercooler with the X intercooler, that that may be the restriction otherwise he'd have replaced the turbo first...maybe my logic is all wrong. Mike, please chime in, thanks.

[Ladogaboy]

I'm guessing since he replaced the lower intercooler hose and intercooler with the X intercooler, that that may be the restriction otherwise he'd have replaced the turbo first...maybe my logic is all wrong. Mike, please chime in, thanks.

As I read it, the cars were otherwise bone stock (still with RA intercooler). It just happens that the RA and X share the same air box. Now, that's not to say that the RA IC isn't a bottleneck (I'm sure it probably is); however, a drop in filter should not precede the IC as an upgrade.

Personally, I'd rather just upgrade both the turbo and the IC at the same time. Just out of curiosity, does the X's IC piping not fit the RA only because of the RA's IC (and not because of where it connects to the turbo)?

[CarGuy]

As I read it, the cars were otherwise bone stock (still with RA intercooler). It just happens that the RA and X share the same air box. Now, that's not to say that the RA IC isn't a bottleneck (I'm sure it probably is); however, a drop in filter should not precede the IC as an upgrade.

Personally, I'd rather just upgrade both the turbo and the IC at the same time. Just out of curiosity, does the X's IC piping not fit the RA only because of the RA's IC (and not because of where it connects to the turbo)?

The RA aixbox is different than the Evos although they are the same size filter. The RA has to deal with a battery under the hood where the Evos is in the trunk. Many parts are RA specific on this car. It's not just an Evo with less parts, it's a GTS with more! It shares more parts with the GTS than the Evo.

[Ladogaboy]

The RA aixbox is different than the Evos although they are the same size filter. The RA has to deal with a battery under the hood where the Evos is in the trunk. Many parts are RA specific on this car. It's not just an Evo with less parts, it's a GTS with more! It shares more parts with the GTS than the Evo.

I see. I thought the airboxes were roughly the same. Either way, with the same size filter, I can't imagine that the airflow through either of the two boxes is that different.

In my experience up to this point, the stock airboxes have never been the bottleneck as far as airflow is concerned. Many people I know replaced their stock airboxes with short rams and CAI and did not actually see an increase in flow. For me, I would need proof that a short ram or CAI actually flows more than the stock airbox with a high-flow air filter before I would consider switching out. And even if the numbers did come back in favor of the short ram or CAI under ideal conditions, I would still need to weigh that advantage against the fact that the stock airbox pulls air from outside the engine bay, is more durable, and is less likely to suck in or be damaged by water and other obstructions.

That's just my two cents. If someone like Mike can convince me otherwise, then I might have to make a trek to Santa Fe Springs for a short ram sometime... but I'd rather save that trip for when I'm ready for modifications that will really make a difference in overall driveability and performance. :p