Hi everybody,

Yesterday my Evo IX started backfiring after a prologed time @ WOT under 1.4 bar of boost. It was weird, because it never happened before.

I pulled a full 6 speed slalom and spent a prolonged time at WOT, I noticed that the coolant temp was on normal operation but my oil temp was around 90 degrees..... usually it will stay between 70-80 at the most. Then the car starting to "lose" power right after 1 bar. I did not try to continue under the situation and continued my drive but this time on vaccum only. After a few minutes, I noticed that the oil temp went back to normal (around 70 degrees).

My mods are: Walbro 255 hp, buschur intake, test pipe, boost controller @1.4 bar and TTM DynoFlash.

Anyone having/had this situation? Where to start to get this situation corrected?

Any comments will be greatly appreciated!

 

Btw, that's not high oil temps at all for racing situations. I regularly get up to 90C just with daily driving on hot days in stop-and-go traffic.

You need to explain this backfiring, because I don't understand what you mean. When was it backfiring, and how? At high rpm, while at full boost, which gear, between shifts, etc etc? I need to make sure you're not mistaking sputtering for backfiring.

 

i/c pipe blew off?

 

Note: Sorry for the long explanation. This time I am trying to get to the specifics of what happen and how. I appreciate your input! :-)

Warrtalon,

I felt this behavior only at WOT and at full boost (1.4 bar per the sport gauges) in gear. I could use partial throtle w/o any issues but could not bring the gas pedal to the floor because a weird symptom was preventing my car to go any faster (I was not over 130 MPH). BTW, the car started to pull normal for the first 100 MPH to around 120sh MPH for about 4-5 minutes “normal” before that started to happen.

The symptom was like the car was making a Puuff, puuff, puuff sound only when I saw the needle of boost past the 1.1-1.2 bar aproximately. The car was on 5 or 6 gear all the time when it did that. It was to the point that my car in order to continue to accelerate.... had to be at partial throtle or the Puuff-Puuff sound was stalling and shaking the car everytime I press the pedal 100% and under full boost. I got the impression/feeling that the car was making more power under 3/4 of pedal than WOT.

It felt like a backfiring/sputtering* with the car stalling and shaking for that moment. Brought the car to neutral, engaged 6th gear one more time and press the pedal 50%... no issues..... but once I pressed it 100% and the needle past ~1.1 bar towards 1.4... it was doing it again. I ran the car for about 10 mins on vaccum (running not under boost) and the car was one more time running fine. I could go WOT, full boost w/o the hesitation.

*=Warrtalon... if you do not mind... can you describe the differences between backfiring and sputtering! Sorry for my ignorance on this matter... but this is my first time hearing it.

Stiguy,

I thought for a moment about that but not sure if that is case…. I can still go on 2nd to 5th to full boost w/o any hesitation. It seems that it started to happen after having the car on full boost, 6th gear and WOT for various minutes.

Thanks for your time and feel free to suggest/comment on this matter! It is my intent to get it corrected as soon as possible.

 

I would suggest thatg you consider taking the car to sporty dyno and doing some dyno pulls to diagnose how the car is running.

Ordinarily when you are going over 130 mph the car goes very rich and it is possible that you may have been getting a miss fire under those conditions - (this is pure speculation without more data)

I would try a fresh set of spark plugs and see if that helps

I will be planning a visit to sporty dyno in July so I can look at the car then

 

I did not know that you are coming to the island. I will keep an eye on the forum for a post indicating the day and the schedule.

If you would, drop me a PM or an email at joedr@joedr.com when you know the dates. I will definetely look for a custom tune on a dyno. That will be the ideal!

In the meantime, what other things you suggest I verify in the car to ensure that everything is normal?

 

Start with the plugs and check the a/f and power on a dyno - then we can move on from there

 

I am bringing this from the dead because I found what the problem was but never documented.

Here is what fixed my problem:

Low boost.... Had to crank up the boost for a lil bit.
Low AFRs betwen 5000-redline at higher load cells.... Bought a WB and correct the tables that were affected to a very nice 11.5 curve.

The car runs very good now!

Note: Al.... thanks for the advice!

 

Great to hear !