3" exhaust and header on a s14 na/ka automatic

[s13pignose]

Yeah I've read the posts and what not about how 3" is better and all of that. I just wanna know what I might be looking at as far as sound on a automatic. I'm thinking on dc headers, and to get the most hp per mod, I'm actually considering the 3" catback. Thinking about getting a direct fit resonator off ebay to put in place of fake cat.

Anyone have sound clips of headers and 3 catback on an auto...I would greatly appreciate. Also I know that the 3" gives more top end, but do you think the gains are to high in rpm for an auto. I mean it can only shift so high.

Thanks

[:: orion ::]

When my car was an auto...the more I modified it, the slower it ran.

[email protected] higher 16s as I added GReddy exhaust, Injen Intake, etc...

You're shifting the powerband to a place the ****ty gearing of the auto can't take advantage of it.

Spend your $$$ on a 5-speed swap, then modify.

Sorry, but that's the facts of life with an auto.

- Brian

[s13pignose]

So say if I decided to stick with the auto, I should try to focus lower. So really I wouldn't benefit too much from 3" unless I got a 5spd?

[teddy]

When you're using a 3" exhaust on a na car, you arent going to see much benefit if any between that and a 2.5". Simple bolt-on's arent going to be enough to utilize the extra 1/2". People on here buy 3" bc they have a turbo, or are planning on getting one in the near future. A 3" is also going to be louder on your car in most circumstances. I say just buy a 2.5" if you really want an exhaust.

[donmeca2020]

3 inch exhaust is for turbo cars only. you'll loose to much pressure from using a 3 inch on a NA car

[onosqv]

Referring to this thread:

5zigen pro racer exhaust dyno (3" on n/a ka24de)

He made gains throughout the powerband. Granted, it is a manual, but the gains should be relatively there also.

About the "shifts power too high," - it is NOT too high for an auto. An auto can shift to 5500 no problem - in at least 2nd gear, which is where most autox, canyon running, spirited driving, some portion of drag racing, and probably drifting auto 240's utilize. I can bounce my limiter up to around 6k.

The power band w/ the 3" exhaust on that particular dyno peaked @ 5500 and started dying afterwards - this is a typical map for most 240's.

In regards to sound, it will be LOUD, especially w/ no cat. Imagine the loudest 2.5" setup you've heard on an n/a ka, a similar 3" system will be significantly louder, unless you run multiple resonators, some special setup, etc.

Of course, modifying an auto produces less power than a manual... how significant is that tho? it all depends on application. I don't believe most of us have the driving skills yet to utilize the full potential of our cars anyway (manual or auto) - there are trade offs for both - it's not black & white that "manual is always better than auto."

From reading this post, seems s13pignose is more concerned w/ looks/sounds since he asked about the sound.

Dyno wise, the best thing to do (if you can spare about $80), is to do a before and after dyno and help everyone out.

[s13pignose]

Good guess, but it's really all about the COPS for me lol. I don't need to spend money on and exhaust only to be told by a officer, that I can't keep it.

They love to single you out.

[onosqv]

then make sure you don't get a single canister exhaust, especially if cops in your area are anal about cat converters and such.

I know in so cal, they bring along a mirror w/ them that they will put underneath the car to see if you have a cat or not... plus it's also very easy to tell most of the time which cars have cats or not simply by the smell of the exhaust fumes.

If you are worried about cops, I'd go w/ something stockish - like the dual tip brm exhaust. Or, the rsr exmag (even tho single canister) but has a big muffler behind it and sounds pretty quiet, even on n/a cars.

If you are really worried about cops, keep your car legal. simple as that.

[s13pignose]

Dag, mirrors lol, they aren't that bad. I think they go off of sound alone. I know a friend who got pulled before.

[morpheus78]

I have a 98 240sx A/T with Hotshot intake, header and BRM Catback. I second that, the A/T robs ALOT of power with the upgrades. Im currently doing my 5spd swap to aleviate the problem. Make your 5spd swap the first upgrade and learn from our mishaps.