I am a new Evo owner (1st AWD, 1st Turbo, 1st best handling car on the planet) and have a question for all of you turbo folks.

About two weeks after I bought the car I installed a Greddy 80mm titanuium catback exhaust. Sounds great, wish the tip was about 3/4" longer so it didn't soot the bumper, oh well.

The next mod was a K&N Typhoon intake system. I installed the thing and it seemed to run fine. The thing sounded awesome since you could hear the turbo spool and the diverter valve makin' it's cool noises.

Anyway I was still in the process of breaking the car in so I didn't hammer the gas at all.

Once the car had about 1500 miles on it I started to notice that the thing pulled great from down low but as soon as it got to around 5000 RPM and above that the car felt really "surgy" for lack of a better term. I know that they cut boost on the thing with max boost at 3500 (19psi) and 16.24psi at 6500.

Anyway it felt like the ECU was pulling a lot of timing out or something because the car just really started to lay down around 5500. I know that the torque peak is at 35k and expected it to let up a little but this seemed pretty excessive. It would be the same feeling as a fuel pump that was too weak.

I've read a bunch of posts about underhood intakes systems and decided to switch back to the stock intake with a K&N drop in filter.

The car seems to run much better. It pulls way more steady all the way through the RPM range than with the K&N setup.

I suspect that with as much air as these things inhale, that the underhood intake was just feeding the engine nothing but engine bay (HOT) air.

I do miss all of the good noise of the cone style setup but the car just runs much better with the stock intake.

Has anyone else noticed the same symptoms on their turbo'd ride?

My Son just bought some really cool software for a Palm Pilot from http://www.auterraweb.com/

The thing will monitor all of the engine functions and will let you datalog two different readings so you can tell things like spark advance, intake air temp, O2 sensors, etc. It will read check engine codes and let you clear them also. Pretty cool.

Anyway I did run it with the K&N and now need to run it with the stocker to see if the intake air temp is what was causing the ECU to go into panic mode.

I did talk to a Mitsu service guy who told me the cars are designed to run on 98 octane fuel. I guess there is a lot of "protection" built into the ECU's for the cars shipped here so they can run on 92 octane.

Anyway if anyone has some advice or feedback that would be great.

Thanks,
Bob

 

Without some kind of engine management most cone filter setups will make the car run lean at certain RPM ranges (different RPM areas for different filter setups) and the car will end up with minor knock from running lean. When the ECU sees the knock sensor activity it pulls timing out very agressively and this results in a substantial power loss.

Keith

 

I could feel a bit of power with my HKS RS Suction kit....

 

Thanks for the info. I can tell that the car definitely pulls a lot smoother with the stock airbox and doesn't have any of the surging feel when the revs start to build. The thing that really sucked was that with the cone style filter you could hear all of the good turbo noises but when it would start to get up around 5500 you could hear the turbo get pretty quiet when they start to vent boost.

 

Go to the vishnu web forum and read on. there are several debates on this subject. I had the k/n short ram in for a while and decided to go back to the stock air box in with the k/n drop in instead. I also have the exede piggyback which needs the stock air box in and all I can say is wow. I am still waiting on my hi-flow cat. I live in a real hot area and taking in hot air is not a good thing. I would prefer constant power over the the hiss and puff sound. good luck.

 

i notice that on mine as well. however each setup as their advantages as well as disadvantages. i noticed a gain with mine but im running more then ur usual setup as well.

 

change the intake tends to make the car run lean but... if you plan to mod further as in:
fuel pump
boost controller
injectors
ecu flash or standalone/piggy-back
THEN an intake would help out as for right now I'd stick with a drop in filter
thanks
adam

 

imo you do not need injectors and or standalone until you are upgrading your turbo. granted they wil not hurt, but spend money on other things first

 

I have looked at a lot of the other tuning sites and it seems that there is a lot of info (both pro and con) about these intakes.

I will post the before and after intake air temps when I run the Palm Pilot software again.

I think the thing that is very misleading is that when a car is run on a dyno, it has the hood open with a couple of large fans blowing on it. With the hood up it does not simulate normal driving conditions at all.

When I ordered the K&N setup their dyn chart showed a 14.4 HP increase at the wheels! That's a ****load for just an intake. The weird thing is that most of the power increase was from about 5000 on up. When I ran the setup on the car it felt just the opposite. It was real strong through about 4500 then really started to let up at 6k.

Thanks for all the feedback,
Bob