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Old 11-12-2003, 08:00 PM   #1
powerlabs
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Default My Rallitek intake made my car slower!?!?!

Ok, so I finally got some time yesterday to install my Rallitek air intake on my 1999 Subaru Impreza 2.5RS. The intake is made for MAF cars so it was supposed to be simple to install and work well with my specific vehicle.
For starters there were NO INSTRUCTIONS WHATSOEVER with the intake. I had to go to Rallitek's site and find a poor description under their "FAQ". The disappointment did not end there, however, as their "very simple" installation took me a good 3 hours with me having to grind bolts and brackets to size, re-drill holes, re-bend the mounting bracket and figure out how to get that F*** snorkus out of the fender well, something that cost me several broken mounting pins.
Anyways, getting to the point: My current engine upgrades are: Borla Headers and Catback system and Unorthodox Racing Under Drive pulley. I didn't notice too much from the pulley but the Borla setup definitely made the car pull harder and accelerate faster.
However after I installed the intake the engine ran extremely rough and almost stalled several times. After the ECU got used to it I went for a drive whereupon I noticed the following two things:
1- The car is now accelerating SLOWER than when it was stock
2- At around 5000 - 5500 RPM the engine bogs down and loses power dramatically, almost as though I was hitting the red line and fuel was being cut off.
I did an ECU reboot by removing the battery cable, letting the engine cool down, reconnecting it and letting it idle (the engine stalled the first time I turned it on after the reboot, but then it idled OK). It did not help at all. I am very disappointed with this because not only is the intake annoyingly loud at high RPMs, but it also robbed me of all the power gains I made with the exhaust and pulley, and then some.
I really hope someone here can shine some light on my problem. The rallitek intake is obviously less restrictive then the stock one so why on earth would I lose power? And why would the engine bog down at 5500RPM??
Your help is very much appreciated. Below is a picture of my installation so you can tell me if I connected anything wrong.
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Old 11-12-2003, 08:23 PM   #2
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Did you do any research on intakes?

CAI of the j-tube design will rob your low end torque, do to the removol of the stock pelnum.

as for why it cuts out at 5500 rpm, cant help you there, I would try resetting the ecu again. Is the check engine light on?

the stall after the ecu reset is normal.

the noise is also normal. You might have been better off just using a high flow air filter with your stock set up. 99s mafs are very fragile and break often when you using a CAI
hope that helps.

Jay
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Old 11-12-2003, 08:36 PM   #3
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same thing happened to me around that rpm when i took a sharp corner right after installing a ganzflow intake on my RS.

felt like i hit a redline @ 5k rpms.

it fixed itself though.

-justin
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Old 11-12-2003, 09:51 PM   #4
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IIRC for the MY99 the MAF sensor is the culprit supposedly the air flow resonates at a certain frequency that confuses the MAF and it happens with most of the short-arm intakes. Try bolting it down tighter with perhaps some cable ties (think big ones). Does rallitek still make the intake for a MY99?
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Old 11-12-2003, 11:47 PM   #5
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Thank you for the tips. I did actually have an Amsoil high flow air filter installed before but with the new pulley and the exhaust/headers I wanted to add a higher flow system and tune it all with the Apexi S-AFC. The intake is not a cold air design; it is more of a short ram than anything else. I'm attaching Rallitek's photo here for reference. This weekend I will try bolting it down tighter and see if that makes a difference (can't find any places to use cable ties).
As far as researching other intakes: I got this brand new for about $80 with the Borla catback and headers, so I didn't think it would have been a bad deal... Appearently I might have been wrong
Can anyone tell me if my hoses are hooked up correctly? Any other suggestions as to what might be the problem?
Oh and yes, Rallitek still makes them for Impreza 93 - 99
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Old 11-13-2003, 09:57 AM   #6
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the 5000 rpm problem is as stated before... the ECU reads that the car is running extremely lean, so it takes drastic measures and keeps it below... the only sure fire fix is to use an AFC... the cobb intake does not have that problem...

this problem is only related to the my99 MAF...
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Old 11-13-2003, 10:45 AM   #7
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Danzborin: You did not have the high rpm lean condition with the Cobb intake? or did you and just corrected with the afc?

curious... The filter setup on the Cobb must keep air flow more consistant with the MAF needs
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Old 11-13-2003, 11:01 AM   #8
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Quote:
Originally posted by Farfrumwork
Danzborin: You did not have the high rpm lean condition with the Cobb intake? or did you and just corrected with the afc?

curious... The filter setup on the Cobb must keep air flow more consistant with the MAF needs
no correction needed... well actully I took fuel out... big time... just goes to show you how bad short rams mess up the program...

the PRM filter keeps the air much less turbulent... I think it's due to the excellent velocity stack from the casing... the filter is also backwards compared to that of a short ram...
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Old 11-13-2003, 01:31 PM   #9
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I installed a Rallitek intake on my '99 DOHC Legacy and my intake didn't come with anything to secure it down with. I've never had your problem but I used some pieces of metal to secure the intake. You might try something like this-
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Old 11-13-2003, 02:19 PM   #10
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Once again thank you for all the excellent replies. I took it to the dealership today and the guy said it was because I put too much oil on my filter. Sounds feasible? Any tips on cleaning the MAF up (can I use water, detergents, etc?) He also said that he doesn't think ressonance is a problem.
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Old 11-13-2003, 05:35 PM   #11
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from what i understand your not supposed to touch the maf with anything, at least those were the instruction from my k&n intake from my supra

but in an old scc mag, they did an article on basic mods to a maf rs, the lost tons of power with an intake until they used an afc
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Old 11-13-2003, 08:20 PM   #12
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Quote:
Originally posted by powerlabs
Once again thank you for all the excellent replies. I took it to the dealership today and the guy said it was because I put too much oil on my filter. Sounds feasible? Any tips on cleaning the MAF up (can I use water, detergents, etc?) He also said that he doesn't think ressonance is a problem.
http://forums.nasioc.com/forums/show...ight=clean+MAF
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Old 11-15-2003, 12:26 AM   #13
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Quote:
Originally posted by DanzBorin
the 5000 rpm problem is as stated before... the ECU reads that the car is running extremely lean, so it takes drastic measures and keeps it below... the only sure fire fix is to use an AFC... the cobb intake does not have that problem...

this problem is only related to the my99 MAF...
Winner! Read the March 2000 Issue I think of Sport Compact Car magazine - they had to add like 26% fuel above 5,500 rpm to correct a lean condition, in cone filter J tube intakes.

I used to think it was likely from the intake valve pulses being reverberating back down the intake, but if the PRM filter you used fixed it, then that blows that theory.
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Old 11-15-2003, 12:28 AM   #14
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Also, the theories about the effect of oil on the hot film MAF is that it causes it to overheat and blow, as opposed to the more durable hot wire MAF. But, that shouldn't cause the lean fuel condition above 5,500 rpm..
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Old 11-15-2003, 12:30 AM   #15
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Ummm... Just clicked that a blown MAF can cause the below 2500rpm drivability problems, and can sometimes affect power too.
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Old 11-15-2003, 11:41 AM   #16
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i just went through the whole oil on the maf sensor thing which realy sucked! ive had a j-bend intake on my99 riht after i bought it. i also have an afc and while i didnt have to add 26% i did have to add more from55oo to 65oorpm's. i never leaned out were i got timing retard though. then again when i had my borla headers on i never got a ce light either. well back to the intake i was always told that on 98/99 j-bends were the way to go even with the maf. tuning was needed but you also got the most powerusually mid to upper rpm's. this is do to the maf being able to measure and compensate for the air flow coming in. the 2000m and up rs's have a map which cant due the measuring of airflow as the maf will. in turn the ganz flow and intakes such as that do better on those years. the ganz flow will give you the same low end but a more stout midrange which is what the rs is all about. also it tends to be quieter which is good. well thts my take on this. oh and i cleaned my maf with carb/cleaner that had tolune in it.
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Old 11-15-2003, 11:52 AM   #17
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My Injen CAI doesn't have the same low end power loss that I got with my Weapon-R short ram. I think hot intake temperatures are another reason your Rallitek is not giving good power down low. I would recommend getting a cold air set up. My Injen gives me good low end and excellent top end power.
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Old 11-15-2003, 03:21 PM   #18
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Yes you will have to richen things up quite a bit with that intake with my old ganz 99rs intake i had to enrichen up to 15% at 5000rpm and slightly more as i went up the rpm band. Just goes to show you that you need an safc when running a jbend intake to get any kind of gains. Now with my Injen CAI i actually had to lean things out quite a bit as well as much as 10% so now you see the difference between a CAI and a jbend style. Its a nice looking intake you have there but being as though i have had both kinds i have to say my INJEN is the greatest i mean little to no low end loss and pulls to redline quite unbelieveably.

Brian
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Old 11-15-2003, 09:04 PM   #19
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Not to jack this thread (disclaimer), but you might look into a Cobb MAF CAI intake if that one keeps giving you trouble. That is, if you can get a refund

I hear their MAF cold air intake coming out for the GC8 chassis (and I think the 2004+ ts/rs) is going to be bent to avoid any leaning out and the typical loss of low-end torque.

If its anything like their MAP cold air intake they sell currently, it will not only be one amazing looking intake but perform in a league of its own.
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Old 11-15-2003, 10:40 PM   #20
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Injen makes one specifically for the maf cars. As for power, my friend with a 98 RS went from 16.1 to 15.5 with just the injen cai. As for me, well I never raced the car before the intake, but in my 01 RS, I ran a 15.005 with the injen. Its a killer intake...
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Old 11-16-2003, 12:30 AM   #21
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or you could make your own which Danzborin and I both did cutting a cobb intake and making fit a MY99 RS. I can't compare it to a injen intake as I don't know of anyone with one local.
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Old 11-16-2003, 05:23 PM   #22
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Quote:
Originally posted by Snagtastic
Not to jack this thread (disclaimer), but you might look into a Cobb MAF CAI intake if that one keeps giving you trouble. That is, if you can get a refund

I hear their MAF cold air intake coming out for the GC8 chassis (and I think the 2004+ ts/rs) is going to be bent to avoid any leaning out and the typical loss of low-end torque.

If its anything like their MAP cold air intake they sell currently, it will not only be one amazing looking intake but perform in a league of its own.
ya know i hate to be mean and all but dont hold your breath on that one bro its supposed to have been coming out forever now and well guess what still no my99 cobb maf intake.

Its hard to compare the injen to the cobb. I myself have the injen and danz had the maf equipped cobb. When danz still had the rs ha we were always together driving but the only problem he has a stick i have an AUTO hehe. if i were to say anything between the two from personal experience... i'd say the injen losses some low end while the cobb doesnt at all but at the top end the injen pulls just a lil bit harder than the cobb

hope that helps

Brian
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Old 11-16-2003, 11:22 PM   #23
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I sell Cobb intakes and Josh recently emailed me that I can start taking orders in a week or two for a 1998-1999 version!
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Old 11-16-2003, 11:32 PM   #24
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That great, I wonder what the 2004+ RS's will do. Possibly that one will fit their cars?


Subybean: No offense taken.

To me it seems Cobb has alot on their hands since the WRX has become so popular. Then again, this crowd is what keeps Cobb in business and able to allot R&D into the EJ25 cars.

However, its testement enough that Josh said he drives an RS and wont discredit the car that got them started in the first place.

Currently they offer more parts than any other tuner I know for the RS and when their products finally hit the stands they always seem to be amazing quality.
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Old 11-17-2003, 12:06 AM   #25
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Thanks to you guys' suggestions I took out my MAF and throughly cleaned it out with carburettor cleaner (toluene based; its all I could find), then I used a K&N filter kit to completely remove the oil from my filter, dried it out and re-oiled it with a lot less oil this time. Then I got in the car and drove from Vermont to NYC. The engine is *definitely* bogging down less; the car goes very fast but I still think that some low end has been lost and regardless of the gear I am in, when it hits 5500RPM it completely bogs down and feels like I've hit the redline. I'm hoping that my Apexi S-AFC will take care of that. It came in the mail today and now I just have to figure out how to install it.
I just can't understand why Rallitek would sell an intake that does not work by itself on the engine. Or is it possible that the 5500RPM cutoff is the symptom of a bigger problem and I'm wasting my time trying to correct it with the S-AFC?
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