98 STS Airbox

[Bob D]

I still wanna know why the SRX v6 makes 260hp and the CTS makes 255 hp; I want my 5 hp darn it.

Slightly different intake manifods? Oil pan windage? Hmm...Intake cams are the same, yes?

[Scotty]

I want my 5 hp darn it.

[Bruce Nunnally]

In 1989, the Cadillac Allante 4.5L made 200 hp. The rest of the line got a 155 hp 4.5L. The Allante difference? New low restriction exhaust manifolds and low restriction air cleaner to go with the same different intake the earlier Allante had. The GM engineers knew how to give the 'line' 4.5L 200hp instead of 155 hp. So why didn't they?

Were the Allante engineers smarter than the nonallante engineers? No, just different trades for different cars. I am guessing it was easier to get the low-production Allantes modified as they needed and that they perceived that more hp was needed for this application, and more cost was okay.

Mods are not bad, if they work. Opening up the intake and the exhaust are classic Cadillac factory mods to make more power. Powertrain said when they tested the K&N cone they dyno'd under 5 more hp on a NS. You can argue 5 hp for $45 and under what conditions, but more is more. The main problem with some air intake mods people have done is that they did not help. Testing is key; seat of the pants is not valid.

Greg did get good results on his Aurora http://caddyinfo.onedgesolutions.com/dyno/4airboxtest.htm but I tried a variety of setups on my NS with no improvement noted. Testing diff things is key to see what does work though.

[BMWburner]

I knew this kid in high school who was totally fastidious about moding his mediocre Integra. He had his car on a dyno and it put down a staggering 108 horse at the tires. He put a god awful intake on it, added an new ECU, changed the cam gears, and gave it the tin can job at the rear end. He continually bragged about all the power he gained. Guess, what? Five months later we had it on the same dyno and put down 93 horsepower. Who knows, perhaps he had worn the engine out with the new gear by that point, but I’m willing to bet all his work was in vain from the get go. Yes, you can modify you car and potentially gain power. The odds that you will be able to do on your own are pretty poor. If you were dead serious about it, you could have a tune shop mod your car. Otherwise, I would leave the tunning to the pros. Intakes are especially tricky to get power out of. That’s why BMW and Ferrari use complex variable duct work for intake systems on some cars. If all you want is noise, that’s cool. I can’t argue with you, but I would put my money into the exhaust if audible stimulation was my focus.

--Ben

[Bruce Nunnally]

I still wanna know why the SRX v6 makes 260hp and the CTS makes 255 hp; I want my 5 hp darn it.

Slightly different intake manifods? Oil pan windage? Hmm...Intake cams are the same, yes?

I have been told diff is in how the air intake is done but have not been under the hood of an SRX to study.

[speedyman_2]

Ok while I don't know who is right or wrong here I'm still going to fiddle around with this. You say engineers spent lots of time and $$$ on the design. They do just about every car in this price range. But, to make this much power and yet, keept the engine quiet and get decent gas milage. Something has to be sacrificed. It's inevitable. You can't possibly think that the setup it has now is getting the most potential HP. I'm sure they wouldn't mind losing a few ponies to get is super quiet to keep the reputation Cadillac have always had. The guys that build the sand rails with these cars sure don't have the airbox on it. And yes I know lots of other things are different that allow it to run like that. But, does this not boil down to the same thing about every engine. It's an air pump..The more you suck in and let out the more power it'll make. While I'm not claiming that, "I can feel the HP gain when I first get in it!!" I can say the throttle response has increased. It's a definate. Of course the sound is there, but that does nothing for performance. I'm sure if I can get cooler air ducted through the same airbox it will have benifits. I'm still using the piece under the hood that holds the PCM. Everything from the bottom of that box to the throttle body is stock. And I won't be changing it. At most I'll be getting a different temperature air. And if I don't gain any HP, at least my PCM stays a little cooler.

[Bob D]

The N* is putting out over 1hp per cubic inch.. No easy trick. Yes, I believe that’s about it, with out major changes such supercharging, turbocharging or No2. The designers of this motor squeezed out every last one they could. To quote one of them, “All the low hanging fruit has been picked”. You can put some high flow mufflers on it, and probably pick a few ponies. Besides that, it’s gonna need headers to make any more true hp, and there’s an inherent design problem there with the transverse design, and crossover pipes. Major change. Good luck.

[speedyman_2]

The N* is putting out over 1hp per cubic inch.. No easy trick. Yes, I believe that’s about it, with out major changes such supercharging, turbocharging or No2. The designers of this motor squeezed out every last one they could. To quote one of them, “All the low hanging fruit has been picked”. You can put some high flow mufflers on it, and probably pick a few ponies. Besides that, it’s gonna need headers to make any more true hp, and there’s an inherent design problem there with the transverse design, and crossover pipes. Major change. Good luck.

Ahh. Ok This I do have to believe. I almost forgot about the +1HP per Cubic inch. But, I still wanna see what happens. If all else fails I can put everything back on. Or maybe do the exhaust, again. (long story). And maybe fab some headers. Who knows, maybe I'll try a wet N20 system this time, instead of the dry shot I had last time.

[Ranger]

At most I'll be getting a different temperature air. And if I don't gain any HP, at least my PCM stays a little cooler.

Isn't it drawing cold (ambient) air in the stock configuration? Mine draws air from behind the left headlight assembly. No underhood heat there. How can you get "colder" than that unless you plan on bypassing the PCM heat, but then you are back to jepordizing the PCM. Am I missing something or just not understanding what you are talking about?

[Scotty]

How about going 100% outside air and fabricating a 92mm 12 volt computer fans to put air through the PCM assembly.

[SGT.ROCK]

The N* is putting out over 1hp per cubic inch.. No easy trick. Yes, I believe that’s about it, with out major changes such supercharging, turbocharging or No2. The designers of this motor squeezed out every last one they could. To quote one of them, “All the low hanging fruit has been picked”.    You can put some high flow mufflers on it, and probably pick a  few ponies. Besides that, it’s gonna need headers to make any more true hp, and there’s an inherent design problem there with the transverse design, and crossover pipes. Major change. Good luck.

Ahh. Ok This I do have to believe. I almost forgot about the +1HP per Cubic inch. But, I still wanna see what happens. If all else fails I can put everything back on. Or maybe do the exhaust, again. (long story). And maybe fab some headers. Who knows, maybe I'll try a wet N20 system this time, instead of the dry shot I had last time.

Ive got an old MOTOR TREND cant remember which issue Ill have to dig in my closet for it , but they take a 1995 or 1996 Olds Aurora with the 4.0 shortstar(baby Northstar) Lower the suspension and add a 100 or 125 HP N2O kit to it. Man what a big boost in performance it made. I think it got into the 14s in the quarter which is a big improvement over stock. But I think they put a K&N airfilter in it and drove down the track to see if it would make the car any quicker. Well the car blew up killing the driver right as it went through the timing lights.Well the filter ended up knocking two tenths off the quarter mile time so I would say that was well worth it. That was a joke, But I do have the mag. with the NOS Aurora.

[speedyman_2]

At most I'll be getting a different temperature air.  And if I don't gain any HP, at least my PCM stays a little cooler. 

Isn't it drawing cold (ambient) air in the stock configuration? Mine draws air from behind the left headlight assembly. No underhood heat there. How can you get "colder" than that unless you plan on bypassing the PCM heat, but then you are back to jepordizing the PCM. Am I missing something or just not understanding what you are talking about?

Umm...Yeah it's cooler than the under hood air. but, that piece that is there is tucked away under the metal the PCM sits on. So it's sucking in air that's stationary. Right next to the engine compartment, Meaning what??....It's not the coldes possible air. There's still hot air coming from the radiator that can still be accessed by this stock piece under the airbox. That's all I'm looking to aviod. More HP maybe not? Colder air, I think so.

[BMWburner]

Alright, speedyman. You should cut a huge hole in your hood and put a hood scoop on your caddy. You'll get a great source of cool air and may nock like like half a second of f your QT time. Thats's only if you put muffin fans on your ECU like scotty said, as he is obveously a computer nerd like me. The big bottle up in power is the crossover pipe on the N*. My friend who drives a Saturn got a big boost in fuel econ and power gain by replacing the intake. But that's like 1.8 L of raw four piston power. The intake on that car really, actually sucks. The intake on a N* is about as good as you are going to get. Mess around with the exhaust and you will gain some real power. Plus, the sweet burble of a N* at idle will sound awsome.

Sorry if I sound like an a hole

I'm just joking around

--Ben

[JasonA]

As Bruce said, research is great. I think it's great that you're going to look into improving the intake tract on your car. It is true that it's probably hard to improve on now, but at least while you're in there, you'll learn a little more about your car, which is always good.

For what it's worth, I bet the air intake is located where it is (pulling stationary air) because of the possibility of water induction in deep water. It's extremely safe where the intake is now...safe from most of the engine heat, external water sources, snow, bugs, etc. I would just consider that factor as you look for a more direct route for air into the engine.

I'm also glad to hear you're going to stick with a paper filter. I bet you'll be happier in the long run. Yes, engines are just air pumps, but you can only flow so much air through 279 cubic inches. It's like swapping out a 2" water supply line to your house instead of the 3/4" line that's already there. Sure, it CAN flow more water. But if your kitchen faucet can only flow X gallons per minute, you're not going to be able to push more water through it (except if it's FORCED through...analagous to a supercharger on an automotive engine).

Good luck, and let us know how you make out!

[Scotty]

Alright, speedyman. You should cut a huge hole in your hood and put a hood scoop on your caddy. You'll get a great source of cool air and may nock like like half a second of f your QT time. Thats's only if you put muffin fans on your ECU like scotty said, as he is obveously a computer nerd like me. The big bottle up in power is the crossover pipe on the N*. My friend who drives a Saturn got a big boost in fuel econ and power gain by replacing the intake. But that's like 1.8 L of raw four piston power. The intake on that car really, actually sucks. The intake on a N* is about as good as you are going to get. Mess around with the exhaust and you will gain some real power. Plus, the sweet burble of a N* at idle will sound awsome.

Sorry if I sound like an a hole

I'm just joking around

--Ben

BMW, is this the MOD you envision?...

[BMWburner]

That's awsome!!

[Scotty]

How about the rear?

[MARK 99STS]

Ok,

Thought I would throw my 2 cents into the ring on this old debate. I took out the entire stock air intake system from the MAF foward. I completely customized a new intake with a K&N cone filter, heat shielded it entirely and ducted out and under with a tube sealed up to the hole in the bottom of the old air box where the PCM sits. Kinda like a poor mans ram air. Yes the PCM was bypassed, but in many exchanged emails with Guru, the stock system was validated in 110+ weather in stop and go traffic. The conditions where I live will never be that severe so I am not concerned about frying the PCM. Yes hydrolock could be a problem if I drove thru extreme high water conditions, yes the MAF could get gummed up but a little electrical contact cleaner fixes that because it already did that once when the K&N was brand new, but I am aware of these things and drive the car accordingly.

I did use my G-tech pro and did track runs with the stock system and the current setup I have now. My current setup was faster, BUT I had already made other modifications before my comparison such as Corsa Exhaust(which was dyno proven to add almost 20hp as a free flowing system. I don't now if Flow masters or others flow as well) 80mm TB, ported intake manifold. I don't know which made a difference or all contributed and also each car is a little different on how it responds to modifications. I am hesitant to say a K&N CONE is better by itself as it may not be, but it works better with my setup.

As far as being able to adjust A/F ratios, there is a piggyback commputer that is in the beta testing stage that sends skewed data to the stock PCM to trick it to think all is well when in reality the piggy back system is controlling the engine. The guy that helped me install my motor is going to help put it on as he is very familiar with LS1 edit and other systems like that. Apparently you data log the engine on a 1:1 ratio and then using a laptop and the program, you adjust components of the engine, but the stock PCM is receiving data sent to it that was data logged under normal conditions. I am not a computer expert but that is how I understand it too work.

I will keep eveybody informed with my progress.

Also I put my resistors in to get around tracktion control amd took it to the track. While it is still very hot out, I ran a 14.4 vs a 14.8 with roughly the same conditions. So I am very optomistic as soon as the weather gets cooler.

[speedyman_2]

then the computer needs to be reflashed. you dont  just strap a car to a dyno and just look at what the bottom line performance #'s are you have to look at the all important air to fuel mixture printout from the dyno run. if you dyno a car bone stock and it made whatever but made a/f curve of 12:1 all the way up and then put on a intake and exhaust that a/f ratio is going to be probably like 11:1 or lower which is going to loose power or have a very small increase or i have seen them start off at 9:1 and end up at 16:1 just from those mods on various different cars. now if you go back into the computer and adjust that a/f ratio to have a smooth curve of the orginal  12:1 that power is going to go up by alot more.

Wow!...

Where to begin...

OK: Long version

This is all correct if you are running a carburetor. Or what’s know as a MAP driven fuel injection system. In these cars they are programmed from the factory to dump in a certain amount of fuel for a given RPM, temperature and engine load. These EFI and Carb systems are basically "dumb"... Carbs are long gone and I think MAP systems are only found on a handful of domestic trucks these days…

Northstars and most other modern engines (built since the late 90's or so) use a fuel injection system based on MAF (Mass Air Flow) In these cars, they actually measure the amount of air the engine is sucking in and then AUTOMATICALLY (and correctly I might add) adjust the air fuel ratio to whatever the engineers deemed optimal (usually 14.6:1). So if the new filter helps, the computer would see all of the extra air, dump in more gas and ta da more power!! Of course lots on this board argue the stock air intake system is already plenty big… And making it bigger will not help a Northstar suck more air.

OK, given that, where do we go from here? First no performance chip exists for the Northstar (at least not now... probably never). GM’s position on this engine is (as I recall from our fav pEng) that it contains too much proprietary, information to assist the aftermarket in producing chips… Of course GM’s position on the LS1 (and relatives) is 180 degrees in the other direction, but that is a different story.

Do the chips work? Yes. Usually they work by causing the engine to run a fuel ratio closer to 12:1 (the magical max power ratio) versus the 14:6:1 ratio which minimizes emissions. One hot rod trick in the early days of electronic fuel injected cars was to fiddle with the engine coolant temperature sensor… If the computer thought the engine was cold it would richen the mixed to provide for engine warm up. This ham fisted approach almost always made power… But you had no guarantee what ratio you were getting. On some engines this just wasted gas as the warm-up ratio was about 10:1 (which hurts both power and emissions)

Short version:

1) If the K&N cone helps; the Northstar computer will add the extra gas without a chip

2) If a chip exists, it would add even more gas at the expense of fuel economy and emissions and yes the Northstar would probably make even more power.

im not going to even try to argue with you if thats what you think then do what you need to do.

PRO94

[speedyman_2]

Ok guys. The moment of truth. Tomorrow night is race night. We'll see what happens. I've had too busy of a week to do any further mods to the car. So it's going to be running with just the silencer out. From what I can tell from driving all week is, the car seems to really respond better at night when temps are cooler. More than stock. More noticeable at freeway speeds As for it affecting my 1/8th mile time. I'm not sure. But we'll see.

[JasonA]

What is your 1/8th mile time/speed now?

[speedyman_2]

My Best is a 9.808. Not sure about 60' and what not. I'll find the time slip.

This is bone stock on my Falken ZE-512 ZIEX.

[JasonA]

Cool. I applaud you for going the extra step to get objective performance data before/after a modification!

[speedyman_2]

Cool. I applaud you for going the extra step to get objective performance data before/after a modification!

Thanks. Tonight's the night. I just got done detailing her and I'm getting ready to leave. Updates later

[Scotty]

Good Luck