Just installed K&N intake - dyno tests disappointing

[RyRy210]

I dynoed my car with and without the K&N FIPK intake, with no other mods, and the car gained 1.9 peak horsepower. However, looking at the dyno sheet, I'm actually losing horsepower up until around 6,250 rpm, then I start to gain all the power back. The dyno said it looked like it was just taking power from the low end and allocating it to the high end. It gained the most at 6,500 rpm, a 5hp gain. Now, my car is an automatic, so basically although I gained a 2 peak horsepower, my car is actually slower because most of my drving is done in the lower rpm ranges. Here is something I put together:

<img src=http://a2.cpimg.com/image/0E/8C/9297422-8f07-02000180-.jpg>

Was this even worth it?

Ryan

[This message has been edited by RyRy210 (edited 31 March 2002).]

 

[FuryNSX]

From the looks of that chart, I'd say "Nope". I have most of my daily fun under 6K, but that's just me.

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1995 NSX-T
1999 3.2TL
2001 Odyssey
1992 SC400

 

[FuryNSX]

BTW, where do you get your car dyno'ed?

 

[RyRy210]

R&D Dyno in Gardena, CA.

 

[NSXTC]

Just for grins once on the dyno I removed the entire air cleaner, running the bare open throttle body. Got a whopping 3 HP increase, but of course that's well within the margin of error of the dyno. We often modify our cars not because we should, but because we can. I think K&N sells a filter for just about every kind of car on the road and is happy to do it. On some cars it may make a bigger difference. On the NSX, the bigger problem is the exhaust restriction.

 

[rmani]

how much power can you gain be freeing up the exhaust with no cats either? also won't the K&N make more power once you're moving since it's designed to work better with air flowing to it.

 

[BoneZ]

I recently removed the CAT's off my car... I only have one thing to say about it ... LOUD and I mean REALLY loud.

I have headers, straight pipes, and exhaust on my car... (along with a ton of other things too) and I can't believe how loud it is.

There are moments when I think its kind of cool, but in general driving, Im finding that its more annoying than anything.

I took my car out a few days ago (after replacing the CAT's with straight pipes) and I got home somewhat late in the evening (around midnight)... the next morning my neighbor came over and asked me "Hey, was that you that came home late last night? Damn your car is loud, did you make any changes?"

I knew right then, that it may be a big problem in the future.

If you are thinking of removing your CAT's, be ready for the change in sound... thats all I have to say.

-B

 

[NSXLNT]

The car performs so well with the cats on, is it really worth the damage to the environment to take them off? Every little bit helps. Those of us who are able to make a choice should consider the impact our actions have. As much as I love driving, I like breathing more. I hope my great,great grand kids will have an even better environment than we have now.JMO<YMMV

 

[Jimbo]

I'm not surprised that there was no difference with the K&N intake. A 2% difference is no difference. It's certainly within the normal variations and tolerance one would even see with multiple runs with the identical car.

I also question, as NSXTC offered, whether or not the bigger problem is exhaust restriction. I guess the consensus is that on the older 3.0L cars, switching to headers will provide some improvement. On the newer 3.2L cars the improvement gained by headers seems to be much less.

It's my impression that intake & muffler changes are done mostly for the "sound effects" only. Headers seem to provide some benefit (5%-15% depending on the year, etc) but certainly don't offer much in the way of "bang for the buck" (as would a supercharger or NOS would).

As far as removing cats...Well it would seem that the annoyance factor alone of inspections-emissions testing would lead this NSX owner to want to leave them on. Although I realize that each state, country, etc has difference rules and laws.

It is somewhat ironic that there are so few NSXes out there percentage-wise - all NSXes ever made could run without cats and it wouldn't make any measurable difference in the environment.

I'm not advocating running cat-less, I'm just pointing out that there's so many more "race cars" out there that do run cat-less, that in the big picture I doubt if would change anything. And I don't really think you gain all that much in the way of HP either.

-Jim

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1992 NSX Red/Blk 5 spd #0330
1991 NSX Blk/Blk Auto #3070 (Sold)
1974 Vette 454 4 spd Wht/Blk
Looking for 76-79 Honda Accords

 

[skim83]

Originally posted by BoneZ:
I recently removed the CAT's off my car... I only have one thing to say about it ... LOUD and I mean REALLY loud.

I have headers, straight pipes, and exhaust on my car... (along with a ton of other things too) and I can't believe how loud it is.

There are moments when I think its kind of cool, but in general driving, Im finding that its more annoying than anything.

I took my car out a few days ago (after replacing the CAT's with straight pipes) and I got home somewhat late in the evening (around midnight)... the next morning my neighbor came over and asked me "Hey, was that you that came home late last night? Damn your car is loud, did you make any changes?"

I knew right then, that it may be a big problem in the future.

If you are thinking of removing your CAT's, be ready for the change in sound... thats all I have to say.

-B

I ran into an Accord that had its CAT's removed while I was at an ATM and it was LOUD...annoyingly so. Now if that Accord owner was my neighbor his car woulnd't stand a chance of seeing tomorrow. I'd do your neighbor, and everyone you run into, a favor and replace your CAT's. Man, just thinking about it gets me pretty worked up...I mean the thing was SOOOO annoying.

 

[nsxtasy]

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[This message has been edited by nsxtasy (edited 01 April 2002).]

 

[nsx4fun]

The comment that removing the CATs on all NSX's wouldn't make much difference to the environment is a nonsense statement. It doesn't matter what you drive, removing your own CAT won't make much difference. But harboring the attitude that my polluting car is OK is not someone I would call a friend. The only way pollution gets minimized is when we all work to keep it in control. Granted, we don't have control over others actions, but the least you can do is not pollute the air any more than you can help. Removing CATs IMNSHO, is immature and selfish, and for what purpose, to add to the noise pollution as well.

 

[DocL]

I really wonder if it's any worse to run an efficiently running engine without cats than an oil burning POS. We've all seen those "Uncle Buck" smokers on the road, and to be honest I don't think that running without cats is very detrimental. In fact, on every car that I've removed the cats, when I've had them inspected they all passed the emissions test well below the maximum levels.

Just because something is Federal Regulated doesn't mean that's necessiarily the best choice. I guess that's why S. Florida has done away with emissions testing altogether.

 

[ktan]

Ditto in Minnesota, they closed all emission stations in 1998 because there was a much bigger cost factor in making emissions mandatory. I remembered reading an article in the local paper about emission standards in newer vehicles being much lower. Environmental changes have not differed in Minnesota w or w/o emission testing and thats why, they got rid of it.

On the same note, i too had the same comment from my neighbor last week, and i haven't driven the car at night lately. It was a friendly remark, but still, gotta respect those neighbors, all i have is an RM cat-back, but then again i live in a new neigborhood where they build houses too closely together!

kevin http://www.kevtan.com

[This message has been edited by ktan (edited 01 April 2002).]

 

[ilya]

I wouldn't remove my CATS just for sounds, weight, or small benefits. To me the annoyances outweigh the cost. Here in CA you need to pass a pretty nasty visual inspection as well and the trouble of putting them back on all the time isn't worth it.

However, for very high HP applications, custom turbos and the like, I can see removing catalytic converters under those circumstances. At that point, chances are you wouldn't pass emissions in CA with or without them.

 

[RyRy210]

Okay, I just remembered something. The base run was done with the traction control off, and the run with the intake was done with it on. You think that will make a difference?

Ryan

 

[NSXGOD]

Originally posted by RyRy210:
Okay, I just remembered something. The base run was done with the traction control off, and the run with the intake was done with it on. You think that will make a difference?

Ryan

Yes, traction control must be turned off when the car is on a DynoJet. You might want to ask to redo your test, especially if the tech didn't know that

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[This message has been edited by NSXGOD (edited 05 April 2002).]