Aftermarket Intake + Bog Issues - Read Here
 

Specs: Scion FR-S with Visconti's Ecutek Tune and Injen intake. 3900 miles on the odometer.

Summary of problem:

A. When rolling in 1st gear at 5mph (because of slow traffic, uphill, etc), and you go near WOT or WOT, the engine and car jerks/bogs and hesitates to climb above 1800rpm. The engine eventually settles and climbs pass 2000rpm. The problem goes away once you pass 2000rpm.

B. Same thing happens in 2nd gear in low RPMS, i.e. below 2000rpm.

Video of Problem:

Watch what happens when the car reaches around 1800rpm. It doesn't look that bad in this video, but the car stops accelerating for a moment and jerks as a result. It has been worse where the jerkiness lasted longer before climbing through 1800rpm.

[ame="http://www.youtube.com/watch?v=4msZh8MIjos"]Injen - YouTube[/ame]

Testing Procedure:

Put car in 1st gear, let car accelerate to 5mph. Foot off gas pedal and let car settle around 5mph, which for me is around 800rpm or so. Quickly increase throttle. Observe whether the revs climb steadily and smoothly to 2000rpm and beyond or not.

Results:

Test Situation 1: Injen intake installed + Snorkel inside bumper - Problem exists

Test Situation 2: Injen intake installed - no snorkel - Problem exists

Test Situation 3: Stock intake installed - no snorkel - Problem exists

Test Situation 4: Stock intake installed WITH snorkel - Problem goes away


Other Stock Cars:

For further testing, I rode with 3 stock BRZs and one stock FRS today at a get together, all manual transmissions.

Observations: All four cars did not jerk at all. All four climbed steadily pass 2000rpm and continued to build power. All four cars were stock with no engine modifications or tunes. The mileage on the cars ranged from 500 to over 3000.



If you have an aftermarket intake installed, or even the snorkel removed, please repeat the testing procedure stated above and report back. Please let us know if you have any other modifications to the engine or ecu. Please vote in the poll and also post details if you answer yes and have modifications. Please also post details if you answer no and have modifications.

I forgot to add options of

Yes - I have a tune only
and
No - I have a tune only.

Please just post in the thread if either of those are true.

NOTE: DO NOT vote no if you haven't done the test. The issue only shows up under specific conditions. It doesn't happen to me until unless I'm in those conditions, which is rare, but it's a very repeatable problem. I've done it at least 20 times now on different days, in different temperatures, and in different road conditions (flat, incline, etc), and it happens each time. It look me a few weeks to realize that there was a pattern and come to where I am today. Unless you did the test as I said, your vote won't count.

its a tune issue only check the your tuner and he can fix it.

Non tuned cars have reported the problem as well.
Nor has anyone that is stock other than a tune reported a problem.

It's also happening with cars that have the stock tune and an aftermarket intake. Let's hear back from others to see if we can isolate what exactly is causing the problem or exacerbating it.

I had a Mazda 3 a few years ago, and when I put an intake on it eventually I had very similar problems. In that case it was because with the intake the MAF wires had less slack than stock, and if you are familiar with Mazda 3s you know that they have very soft engine mounts, so the movement of the engine coupled with the extra tension on the MAF wires ended up breaking them. I'm afraid this kind of looks like a similar situation. If it is the same thing, the problem will get worse over time. I would say it is showing up only in first gear right now because first gear is when the engine moves the most.

I should add that I installed my Airaid intake today, and don't have the problem, but am concerned with how the MAF wires look pulled under this application.

Did you do exactly what I did in the test above? It only shows up under specific conditions.

This probably has to do with excess turbulence at low RPM and high throttle causing the MAF voltage to freak out.

Probably emphasized with a tune, but affecting some people without.

If you voted no and has an intake or tune, please clarify whether you actually repeated the testing procedures. If not, it doesn't really count unless you happen to mash the throttle from a low rpm state frequently. It took me about 2000 miles of driving to come across situations where it occurs.

Just tested this tonight. It doesn't happen all the time, so I'm not sure if I'm doing this consistently enough, or if the culprit is intermittent.

have you done a datalog yet while replicating the condition? I'm sure that with a datalog, @Visconti would be able to pinpoint the issue fairly quickly.

Thanks for the tip. I believe someone else already did. I'll check with him when he's less busy.

To those who said no and have intakes, please post to let us know if you've actually tested it per the original post.

First, some back ground info

I have a 6MT BRZ Limited with just over 2000 miles.

My mods thus far are Perrin crank pulley, SRT HB Exhaust, and Visconti STG1 e85 tune. With these mods, I've never experienced any issues.

After installing the AIRAID intake, I immediately noticed a loss of low end throttle response. I originally thought it was just the ECU going through it's learning process. However, the car started occasionally cutting power and jerking while pulling away from a stop or accelerating heavily from low RPM. I managed to capture this on a log seen here:

http://www.ft86club.com/forums/attac...1&d=1345752122

Under heavy throttle, the MAF reading started spiking up and down. As a result, the ECU cut all the ignition timing. I sent the log to @Visconti and am waiting to hear what he says.

Now, Cobb uses "air straighteners" in all of their subaru intakes right before the MAF. The stock intake also uses these. An example is here:

http://img233.imageshack.us/img233/7116/35yu.jpg

I'm willing to bet, the stock MAF is tuned to use these and having the MAF so close to the velocity stack is messing with out readings. I'm surprised aftermarket companies overlook these. Especially with these molded plastic parts, it would be entirely easy, and cheap to implement.

That's my theory anyway.

I am going to hold off on installing the Airaid intake I purchased, and keep an eye on this thread. Hopefully, there will be a fix coming, as it seems enough people are experiencing issues with the MAF.

I have the Injen intake installed as well, WITHOUT a tune. I have not had any issues with a low rpm take off in 1st gear.

I'm kindof worried now, i participated in the Visconti stage 1 tune group buy... I'll definitely report back if I experience issues once I do the tune.

I don't think it's related to the tune. I've seen more people on stock tunes have issues than us with tunes.

If you don't mind, please do the test as specified in the original post if you haven't already. Thanks for you input so far.

The install is really easy and I wouldn't worry about it. If you don't mind, please install it, do the test as specified, and report back. Worse case scenario, you just reinstall the stock intake. Best case scenario, your intake works fine. I can do a swap in about 10 minutes now. It's not that bad.

Thanks for starting this thread. I feel bad for bombarding Airaids thread with this, but I didn't like that posts were being deleted.

As I posted in that thread, I have this issue. My mods:

-Airaid intake, sound tube and snorkel deleted
-Perrin crank pully
-Visconti Stage 1 tune

I run 93 octane fuel with ~10% ethanol in it (unfortunately). I dont need to go WOT for it to bog either. I gave it just a bit more then 50% throttle yesterday at 2k rpms in first and the engine fell flat on its face.

I've noticed that throttle response below 4k rpms is lacking as well. Starting off in first gear takes more throttle then it used to. I, too, plan on sending @Visconti a log.

the problem isn't your intake, its the tune! the tune is not set up for the intake... I would talk to your tuner and see if they can create a custom map for you

Tune or not
 

Bimmerboy

It says above (read all the posts) that the condition exists on stock and non stock tunes.

If you read through the thread and the airraid thread you would know people without the tune are having the same problems.

Exactly!! The stock tune AND the Stage 1 tunes that are floating around are not properly setup to handle these intakes.

I even remember perrin addressing this in one of their threads, stating that their intake will require a tune if used...

I'd be a bit peeved if I dropped the cash for one of these intakes and was then told I'd need a tune to have it work properly...

This graph probably describe your issue. If you want to read about it here the link.
http://farm4.static.flickr.com/3046/...6e761897_o.png

This sounds like the problem. The air straighteners in the stock intake are there for a reason. When switching to the CAI/SRI the MAF is not able to read the air flow correctly because its just a sucked in, and it might not be getting picked up correctly as it "swirls"(dunno how to describe it) past the MAF.

With the straightener it allows the air to do just that..straighten out for the MAF sensor. This was a big issue for the 6th gen Civic Si's. When Injen, and AEM released their CAI for the cars, people were bogging down, and throwing CEL because the MAF wasn't detecting the air right. It could be resolved by flashing with a tune, and switching to MAP. But most people didn't want to have to do that. I know that AEM released a 2nd version with "veins" around the MAF sensor which resolved the CEL issue and any bogging down without needing a tune.

With that said, I'm not sure how our ECUs work, and I don't know if we can switch to MAP or not. But it sounds like the intake companies need to install veins into the intakes for our cars.

I thought the reason or at least one of the reason for the velocity stack was to straighten out the air.

Is the MAF now located before the velocity stack?

I wonder if the intake manufacturers are now going to provide some sort of add -on kit.

Now that there are some postings on the mass air flow, given the STOCK/NO PROBLEM scenario, how is it suppose to look?

No, Perrin has 2 intakes. One that does not require a tune and one that does not. If you can't contribute to the thread, don't post.

Here's a link for you.

http://www.ft86club.com/forums/showt...=perrin+intake

"What we have learned is we will be offering two intakes. One that runs very close to the stock MAF curve, this will suite the more common customer that doesn't need or want a tune, but would rather get some really cool sounds along with a bit of HP. The other intake will require an ECU retune, and is designed for the customer who wants the maximum HP from his car."

Can people please use a search function before claiming to know things?

I had that jerk coming from the engine as soon as i installed the injen short ram.
I disconnected the MAF Sensor and started back up the engine.
Then Reconnected the MAF Sensor and started back up the car.
And after i ran the car for 4 mins under 2000rpm so the ECU could Accept the new intake and not jerk anymore.
I restarted the car 4 times and ran it and the check engine light came out, and the car stopped jerking and ran way better.

I've reset my ECU twice thus far and still get the problem. Glad it fixed yours though.

I really think these vanes are the answer. I remember reading something similar on the Celica forums a couple years ago.

Correct me if I'm wrong, but I thought the purpose of a velocity stack was to improve the velocity of air entering a confined space (tube). That doesn't necessarily straighten the air out.

Companies shouldn't have to release 2 designs to accommodate tuned and stock setups. I looked at the stock intake and the vanes aren't all that thick. They wouldn't restrict any airflow. I know Cobb has a piece with both a velocity stack and vanes. On their website it's 195$ for the intake kit including this piece, but maybe I can find one used for cheaper to do some testing.

The unfortunate part is that, because we are so small in numbers, I doubt any resolution will occur. I also have the aFe Takeda intake on order. I'm hoping they included the vanes in their design, but I'm not holding my breath.

I'm definitely going to be getting some seat time with @Visconti, as soon as the vendors stop hogging all his time for their turbo kits. We will get to the bottom of this. A 3D printer would make this so much easier to test haha

350 Z has same issue
 

My 350 Z also lost power and ran rough with the stock airbox and a short ram installed. Turbulence at MAF was reason I believe. (A while ago:)..

The stock tune is what comes from Subaru.

You should really read the massive thread on Nasioc. Just get the car re-tuned for the intake once people know what they are doing. :sigh:

Did you read about the guy that had this same problem with a tune and stock intake with the resonators taken out? Makes sense. It has to be an intake resonance problem that probably exists in every BRZ that runs without the stock resonators. Some setups will probably react more radically than others, like cars running the visconti tune. Even the subaru engineers said this car has issues with it. It's been said that's a reason for the torque dip that nobody can explain. When you took out the stock intake did you notice all the crazy helmhortz chambers?

Your best course of action might be to either wait for Visconti to get some time to really investigate the issue or contact TiC and see if they can help you out since they have fixed this issue in the past (with a tune).

I'm going to. But you're missing the point completely. Injen and AIRAID sell intakes under the impression that they work without needing a tune. Neither explicitly say "You may need a tune in order for proper operation of the intake".

What about the people who are having issues with the intake, but don't want to spend 1000$ on tuning the car? The ECU cables are on backorder for at least a month. Are these people SOL?

We get it, you enjoy your intake and it actually works for you. Congrats. The people in this thread aren't so lucky. You're not exactly helping the cause by basically telling us to shut up and deal with it. I've already spent 250$ on the intake, and now I have to go and spend more money having @Visconti fix the issue with it? Try putting the shoe on the other foot.

I live in the city, and there's no point in using this product if I can't drive around where I live. Plain and simple.

The intakes do seem to work fine without a tune on an otherwise stock car. The very nature of internet forums is that problems are overrepresented. If it was really widespread, people would be coming out of the woodwork. It does seem widespread that there is a problem with aftermarket intakes and off the shelf tunes...

I'm not sure why you seem so upset that an intake is causing your car to do weird things when added to an off the shelf tune which did not originally take into account that there would be a modified intake. Intakes have to exploit the stock computer to make more power. They do not run exactly the same as the stock intake. If they presented exactly the same air and information to the car, they wouldn't sound any different or make any power anywhere in the rpm range. They have to change something. Just because something is compatible with the stock tune doesn't mean it's exactly the same as the stock part. It's like running a mild piggyback tune on top of an ecu flash.

All this said, I understand alot of things about cars but dealing with intake resonances is above my head. It sucks that you have an issue. Subarus are pretty notorious for having issues with intakes. Have you looked at the treadstone air straighter? It should be easier to add than the Cobb one. it might fit in that gap between the MAF sensor and the velocity stack. I honestly don't think straightening the air will fix this issue but it's hard telling not knowing. Thanks for paving the way though. Someone has to do it! :lol:

If it were only my car, I wouldn't be saying much, but seeing as a few people with completely stock cars are having the same issue. That tells me the tune isn't necessarily to blame.

The MAFS is calibrated a certain way. It sends a variable voltage signal to the ECU to account for how much air it sees. An aftermarket tune can't touch this calibration. Aftermarket tunes deal mostly with the reference maps the ECU uses to control the engine. Fuel trim, ignition timing, variable valve timing, temperature correction, etc. Tunes from individual vendors like @Visconti take the stock maps and adjust the values to obtain more power that may have been conservatively tuned out from the factory.

The problem we are having is from 1000-2000 RPM. I doubt that specific RPM range of the maps were deviated from stock values by anything drastic enough to cause the issues we are seeing. They aren't a target for the power band. I mean how many times do you see 1000-2000 RPM while doing any kind of racing/aggressive driving? Visconti doesn't even show this range on his dynos.

The point of failure in this equation is the MAF reading. It's the only thing that could change the way the ECU could react enough to cause the problems we are seeing. Resonance is a factor and all, but not enough to cause a WOT motor to lose that much power. The manifold air pressure in my log was high enough to indicate that sufficient air was available to the motor.

But you are right in some regards. I'm certain a tune can fix it. However, it's a hard thing to swallow for people who just wanted to spend the 250$ on the intake without having to buy an ECU tuning kit just maintain day to day drivability.

I'm almost through my tank of e85. I will be filling up with 93, flashing to stock, and doing some more analysis. But I feel the result will be the same.

Sometimes there is a price to pay to be the pioneers testing products real time, daily driving on the street. Unfortunately, this is the price people are paying right now. I think anyone who is not willing to deal with these trials and tribulations should just return their aftermarket intake, wait for it to be resolved and buy after the solution is found.

I was eager to get an intake but after a while realized I need to wait for parts to be tested on the street in daily driver cars. I don't have time or patience to deal with this kind of stuff. Good luck to all that have the problem and I hope a solution is found very soon. If it were me, I would get my money back and wait. The "discount" price at which you guys were able to get the part IMHO is not worth the headaches.

I love how some people ignore the stock tunes that are having these issues as well...

Sent from my Nexus S using Tapatalk 2

you just proved my point :thumbsup:

People aren't.

Take a look at the Vote !

Maybe in bizarro world. They have an intake that does not require a tune, however, they are making one designed specificallyfor a tune.

The airraid, injen, tanabe, etc... Are all similar to the first perrin intake that is designed to work with a stock, untuned vehicle.

Also, visconti stated his tune wil work perfectly with an intake designed to mimic the stock intake "10000000%".