Still Feeling Paranoid About my HKS SRI

DaleNixon

Member
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2001 Miata, 2011 Mazda 2
The title says it all. I've had my HKS SRI on since early November. I've had no CELs, and the Dashhawk reports AFR's fluctuating around 14.69:1 while cruising/idle and has gone as low as 10:1 at WOT.

I read some criticism of this intake for "bad fuel trims" (with nothing to back that up) as well as some people criticizing the foam filter it comes with does a horrible job of filtering based on a study that's over 6 years old.

So the car SEEMS just fine with the HKS SRI. There is no air straightener before the MAF that I'm aware of, but I've read that the mushroom shape of the intake serves this function.

I don't want to hurt my baby, and the intake seems fine, but peoples' comments do worry me a bit. I plan on changing my wet filter for a dry filter after 5,000 miles then sticking to dry filters from there on out.

I just don't want this intake to wreck my engine with bad fuel trims and/or destroy my turbo with a subpar filter.

Can anyone chime in on the HKS SRI? There isn't much information out there about this intake for our cars. It SEEMS like a fine piece, but I'll switch to Cobb or something similar if someone can tell me that this intake poses a real threat to my engine.

Thanks!
 
I wouldn't worry if you can monitor your AFR yourself...
But like stated above, if you can't manage to feel safe running it, then you should get a cobb, cp-e, AEM, or Mazdaspeed intake.
 
Well I can monitor the AFR, but I'm not exactly positive on what to look for. I'm not positive on what are considered "bad fuel trims". Can any experts chime in?

And yes, I realize I could just switch to a more common for our car intake, but the quality of the HKS is top-notch, I don't have any CELs. I know this doesn't mean there isn't harm being done.

I'm thinking I'll keep the HKS on and check my MAF sensor after the first filter change to see how dirty it may or may not have gotten. I would think that would be a good indicator of how well the filter works.
 
You should monitor your LTFT (long term fuel trims)...they should ideally be at 0.0%; most people I think are in the 0.0-4.0% range. Mine are exactly at 0.0% after getting the AEM airflow straightener for my MSCAI and a little tuning. Just setup a screen in your DashHawk that shows STFT (short term fuel trims) and LTFTs...they should be ideally both 0.0% at idle once the car is at operating temperature. The LTFT is basically telling you how much the ECU is having to add/remove fuel to run at target. The number closer to zero is the best. If you are running 7.0-16.0%, then its bad...not bad to where your engine will blow up or anything...never heard of engines blowing due to LTFTs, but its definitely not running ideally.
I hope that helps.
 
Thanks AutoXRacer. I'll try that when I get off work tonight.

Does anyone have any input on HKS filters sacrificing good filtration for airflow? http://www.mkiv.com/techarticles/filters_test/2/ <--- This is the original test that had me worried, but the conclusion made a lot of sense:

It is questionable how accurate the original source of data is, as HKS are proven to sell more induction kits than any one of the others featured in the test, and yet there induction kit rates as the worst kit in the test. This suggests that either HKS rely upon their brand name to sell their 'poorly' manufactured air filters, or that the original Japanese test was nothing more than a PR stunt to promote the lesser known equipment. HKS and Blitz continue to be the best selling induction kits in the UK, and are used by Middlehursts, Hiteq and Abbey Motorsport as their first choice when the induction kit modification is carried out.

One thing that does stand out is the fact that all the induction kits seem to offer similar performance gains, of around 13 - 14 bhp. This would seem consistant with actual power gains that have been confirmed by using a rolling road.

So the question still stands, "Which Induction Kit is the best?". Well, if you can trust the original source of data, then the clear winner is the Apexi Power Intake. For those of you that are more sceptical, the choice is probably more to do with the cosmetic looks of the induction kit, as the performance gains are very much the same.
 
I haven't pulled off the filter and checked out inside yet, but it's only been on for less than 1,000 miles. I'm using the wet filter that came with the intake, but I'm planning on switching to their dry filter when that one is used up.

I wonder if this hydroshield would fit over the HKS, and if it would give me even more filtration:

http://siteground207.com/~protegeg/product_info.php?cPath=160_258&products_id=1521

If anyone else on this board has the HKS SRI and would like to chime in, please feel free! I know AAMGuy has one and loves it, but he's only talked about the performance gains. Longevity of the engine/turbo is just as important to me.
 
Usually foam filters do a much better job of filtering particulate then the K&N style wet or dry filters.. Coming from an off-road application perspective most individuals in harsher climates run a foam filter opposed to a K&N style because it does a way better job doing what its supposed to do; FILTER! While K&N style filters do allow a little more airflow volume the foam will filter smaller particulate. Read this article (quite extensive) and it will explain why.. But in all honesty I wouldn't be worried about it that much, just keep it clean and oiled and you'll be fine..

--http://www.bobistheoilguy.com/airfilter/airtest1.htm
 
Yamaha72,

I've read the opposite actually. I've read that foam filters aren't as good as the canonical style filters. Of course, this is usually just people shooting their mouths off in forums trying to justify what they've purchased.
 
here's where some wiseass will chime in with this gem:

if it aint broke.......................
 
I have read that test before. My ex roommate also had an HKS intake years ago and it sucked in and failed to filter dirt particles which ruined his turbo. He was told this after everything was taken apart. It was an Eclipse GT-S and he had to put a new turbo in it. Now mind you this was YEARS ago and I'm sure HKS has developed since then and the filters are possibly better. Personally though I'm ditch the mushroom filter on the end and get a dry mesh one like Apexi or Fujita or something. Just my two cents.
 
Do you know if your roommate replaced the filter frequently? I've read running a dirty filter for a good while will pretty much guarantee dirt in the turbo.

I was considering maybe an Apexi filter. Which one would I need to get and how would I mount it on the HKS piping? Also, would AEM's air straightener fit in the HKS piping with the Apexi filter? Thanks.
 
Honetly I have no idea if he changed it a lot. I'm not sure which Apexi filter you would need to use. When I was looking into getting an HKS and changing the filter out I remember they all were measured by the ID i think. I'm not sure how diffrent they are but te Fujita filter LOOKS just like the Apexi so that may be an easy alternative.

Sorry I can't help more.
 
Usually foam filters do a much better job of filtering particulate then the K&N style wet or dry filters.. Coming from an off-road application perspective most individuals in harsher climates run a foam filter opposed to a K&N style because it does a way better job doing what its supposed to do; FILTER! While K&N style filters do allow a little more airflow volume the foam will filter smaller particulate. Read this article (quite extensive) and it will explain why.. But in all honesty I wouldn't be worried about it that much, just keep it clean and oiled and you'll be fine..

--http://www.bobistheoilguy.com/airfilter/airtest1.htm

that site says foam is just as bad as K&N style...but thats why you would use oil. Most other studies will all agree that foam is the worst...flows well, doesn't filter worth a damn. And generally, offroad filters have 2 parts, foam is the outer part and paper or K&N style on the inner part along with oil.
 
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So I've been on the phone with HKS a couple of times. They tell me that the intake will not harm my turbo (of course they will say this about their own product). They stress that maintenance is the key (you gotta change those filters). The woman I spoke with has a boosted S2000 and an Evo. Of course she's running HKS intakes on both of them.

She told me the bigger threat to the turbo is "oil blow by". Supposedly a catch can install can keep some of that crud out of the turbo. Any truth to this? They are really helpful and reassuring on the phone, but I know they won't badmouth their own products and ultimately it's up to me.
 
You should monitor your LTFT (long term fuel trims)...they should ideally be at 0.0%; most people I think are in the 0.0-4.0% range. Mine are exactly at 0.0% after getting the AEM airflow straightener for my MSCAI and a little tuning. Just setup a screen in your DashHawk that shows STFT (short term fuel trims) and LTFTs...they should be ideally both 0.0% at idle once the car is at operating temperature. The LTFT is basically telling you how much the ECU is having to add/remove fuel to run at target. The number closer to zero is the best. If you are running 7.0-16.0%, then its bad...not bad to where your engine will blow up or anything...never heard of engines blowing due to LTFTs, but its definitely not running ideally.
I hope that helps.

My LTFT is definitely within 0-4%. The STFT would spike pretty high in either direction, but this was on my commute home with lots of stop and go traffic and some A/C action.
 
Ok so I think I'm going to ditch the HKS.

Obviously, I want to get the right intake this time! I'm trying to decide between CPE or Cobb.

I'm leaning towards CPE because the filter is dry and the air straightener can't be bent and I haven't read anything about the mounting bracket breaking anything.

HKS just can't tell me anything technical on the phone other than "an intake won't harm your engine". I can't get them to get Mazdaspeed3 specific for me. I don't think HKS USA would know anyway... they seem to be primarily sales. This intake might be perfectly fine, but I'd like a little more assurance that a part as trivial as an SRI won't damage my turbo. It will probably be for sale on here soon!
 
either intake works. The Cobb bracket problem is rare, but you can run it without the bracket anyway...its light weight. I removed the bracket on mine and it moves very little and doesn't sag at all without it.
 

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