: 98 STS airbox mod?



speedyman_2
09-03-05, 07:25 PM
Well I want to mod my airbox and put in a K&N filter. I tried the other day and it was pretty simple to remove the upper portion of it. But there is another piece under it that curves down and then back up. I dunno how many of you have seen this, but I can't get that lower part off. It's stuck in there pretty good. Seems like I would have to remove the bumper cover to access the bolt that holds it in. ANyone know how to get this thing out??

speedyman_2
09-03-05, 08:55 PM
Here it is, I got it out. Or My friend got it out. It needed a little muscle.

http://i15.photobucket.com/albums/a378/speedy_3/HPkiller.jpg

Sounds way better and has way better throttle response.

Ranger
09-03-05, 09:57 PM
It may sound better, but any perceived improvment is just that. The OEM filter will flow all the air that the Northstar needs or will require, even at WOT.

eldorado1
09-03-05, 10:24 PM
Wanna see how much DIRT a K&N will flow?

http://home.usadatanet.net/%7Ejbplock/ISO5011/Spicer_files/image010.jpg

Stock air filter - 0.4 grams. K&N - 7 grams. That's 1,750% more DIRT going into your engine. Air filters are supposed to filter the air... right? Might want to tell K&N that.

lry99eldo
09-03-05, 10:32 PM
One more time..........you'll get nothing out of this bolt on and that odd shaped hole in the plenum box, is meant to cool the unit under it as well as stabilize air intake temperature and flow characteristics. You may even loose a mile or two per gallon. Congratulations, you've spent money and time for 0 gain.
lry99eldo

speedyman_2
09-04-05, 01:26 AM
i did not install a k&n filter. i said i would like too. all i did was remove that big ass piece of plastic. to improve airflow.

Ranger
09-04-05, 02:12 AM
If the "big assed piece of plastic" you are talking about is what I think it is, that routes intake air over the PCM to cool it. I would be very hesitant to re-engineer something like that at the possible cost of a new PCM. PCM's are not cheap. The perceived gain may not be worth the evenual cost unless you believe that the engineers who desingned it were clueless.

mcowden
09-04-05, 02:40 AM
If the "big assed piece of plastic" you are talking about is what I think it is, that routes intake air over the PCM to cool it. I would be very hesitant to re-engineer something like that at the possible cost of a new PCM. PCM's are not cheap. The perceived gain may not be worth the evenual cost unless you believe that the engineers who desingned it were clueless.

In the bad old days of American automotive engineering, allowing a piece of plastic to choke off power and fuel economy would probably go unnoticed. Today, I just don't believe anybody is going to let a piece of plastic or an air filter rob the car of horsepower or fuel economy. The car's power and fuel economy are selling points. Why would they cheat themselves out of 10 horsepower by putting in a restrictive air box or air filter, especially when there is so much more competition out there? I just don't see that happening, and I'm not about to put the PCM at risk for heat-related failures to get what so far nobody has proven is even possible. On a Civic, you might be able to get another 50 horsepower with a Type R badge and a K & N sticker if you ask anybody who sells or installs aftermarket ricer parts for a living. The same thing doesn't work with a Northstar.

I'm not saying you shouldn't do whatever you want to your car, but don't let anybody tell you it's going to give you any benefits unless they can prove it on a dyno. My guess is that, in reality, there will be very little or no measurable difference at all. If you want to prove it to yourself, take the whole airbox out, filter and all, and see how well it performs. Then there's no restriction at all. Then put the whole thing back in and check it. Post the dyno and track results and prove us all wrong. I'm not going to hold my breath.

speedyman_2
09-04-05, 04:14 AM
If the "big assed piece of plastic" you are talking about is what I think it is, that routes intake air over the PCM to cool it. I would be very hesitant to re-engineer something like that at the possible cost of a new PCM. PCM's are not cheap. The perceived gain may not be worth the evenual cost unless you believe that the engineers who desingned it were clueless.

No, this piece is below that. The PCM is still in its original location. Air will still flow over it the same way it did before. This lower piece is pretty much there for silencing. Which it did a good job at. As fas as me getting anymore HP from removing it, I doubt it. Throttle responsed improved. And the sound is nice. I'm still not done with this though. I'm going to try to connect more tubing and route it to some colder air. Maybe even somewhat of a ram air if I can get a good location. I'd have to seal the rest of the box because the part that contains the PCM isn't fully sealed. I'm sure I can at least pick up a little more throttle response and maybe a few HP with this. I'm also going to be modding my other throttle body I have laying around.

danbuc
09-05-05, 10:54 PM
That large chamber at the bottom of that U-Joint looks like it was designed to capture any water that may make it's way to the opening of the intake, and prevent is from reaching the airbox or engine. It also probably helps to reduce induction noise like the large plenum attached to the hose that leads from the airbox to the MAF. Removing that section hasn't done anything but provided and easier path for water to reach the airbox.

speedyman_2
09-06-05, 03:21 AM
That large chamber at the bottom of that U-Joint looks like it was designed to capture any water that may make it's way to the opening of the intake, and prevent is from reaching the airbox or engine. It also probably helps to reduce induction noise like the large plenum attached to the hose that leads from the airbox to the MAF. Removing that section hasn't done anything but provided and easier path for water to reach the airbox.

True. But I'm in So Cal. I can't remember the last time I saw water other than the ocean.

danbuc
09-06-05, 04:42 AM
Oh well...being in California you really have nothing to worry about then.

tremor12
09-06-05, 08:10 AM
That large chamber at the bottom of that U-Joint looks like it was designed to capture any water that may make it's way to the opening of the intake, and prevent is from reaching the airbox or engine. It also probably helps to reduce induction noise like the large plenum attached to the hose that leads from the airbox to the MAF. Removing that section hasn't done anything but provided and easier path for water to reach the airbox.

It has absolutely nothing to do with water. It is simply a resonance chamber meant to tune out specific frequencies. Removing that section and replacing with a duct from underneath, along with a heat shield that keeps engine heat from the filter will do nothing but good. I've done this on both and Aurura and a STS and there are gains to be had by opening up the intake...

danbuc
09-06-05, 12:56 PM
I guess you missed it, but the second have of that post I made was about reducing induction noise. If removing that piece is going to make that much of a difference, than removing the resonance chamber attached to the hose between the airbox and the intake manifold should also increase performance as well. It doesn't though, and there a good reason for it. Just removing that section of tubing isn't going to do much, since it is not a restriction. If it was, it wouldn't be on the car in the first place.

Also, what do you mean heat shield to keep hot air away from the filter? Are you suggesting an open element filter assembly underneath the hood? Even with a heat shield, any kind of cone filter, is probably not going to flow properly, and will most likely mess with the MAF signal. A simple piece of duct work leading fomr the whole beneath the airbox, to the front of the car doesn't make much sense, since that's what that tube in the picture is used for. It was obviously designed for a reason, which is why it's on the car.

mcowden
09-06-05, 05:25 PM
It has absolutely nothing to do with water. It is simply a resonance chamber meant to tune out specific frequencies. Removing that section and replacing with a duct from underneath, along with a heat shield that keeps engine heat from the filter will do nothing but good. I've done this on both and Aurura and a STS and there are gains to be had by opening up the intake...

What are the gains, and what are the pitfalls? There has never been a good, real-world comparison done. The evidence seems to point to few or no gains from modifying the stock airbox and hoses, and possible PCM damage by reducing airflow. Whatever the purpose of the airbox, how much does it restrict air flow? It doesn't look like it interferes at all.

Again, you can easily test it for yourself by removing the intake hose completely and running with no filter. Then there is zero restriction. Don't run it for long like that, but in a relatively short time you can tell exactly what gains are to be had by "opening up the intake."

speedyman_2
09-10-05, 05:41 AM
OK guys. Results are in. Just got back from the races. I made 8 Passes tonight. As for the PCM...this mod is after the PCM. There is nothing but colder air passing over it now. And more of it. I did not bypass it nor restrict it.

Here's an over view of before and after timeslips. I showed RT's not that I thought these would be affected by this intake mod though.

Before:

Best RT: .503
Best 60ft: 2.370
Best MPH: 74.50
Best ET: 9.808

After:

Best RT: .501
Best 60ft: 2.314
Best MPH: 76.27
Best ET: 9.613

Now. While some of you might think there might be other variables that changed, I would doubt it. temperatures were pretty close to the same. I raced all throughout the night like I always do. With all the runs spread out throughout the night. With all the races I've done, and the mods I previously had. Like, the Magnaflow's, or the Nitrous. I never once saw anything below a 9.7 This was on the old N* I had. These time's I've posted do no include the 9.7 run, which was with the Magnaflows. And I only got into the 9.7's once with those. Nitrous never saw anything below 9.8
Bone stock with the new northstat put me at 9.808 at best. This was with fresh oil change. Tonight I'm actually on 4,000 mile oil. I'm running synthetic and don't worry I've topped off with the normal quart between changes. Judging by the time comparisons, I would say that removing this part helped on the top end. 60ft times we're pretty close to the same. But the ET's are what I really noticed a difference in. As soon as I passed the finish line I knew, "this was a really quick run." All I can say is, "Numbers don't lie." Other than that it was a fun night and pretty cool that I ran such good times. I almost won the trophy for best RT, but right at the end someone came up with .500, a perfect light. Anyhow, I did manage to beat a few cars I thought I wouldn't. Like a really nice looking Chevelle with a 350. And a few imports. More on this tomorrow. I'm ready for bed now :)

lry99eldo
09-10-05, 01:34 PM
I'd say your RT's are very very good. As a drag racer since '63, I'd be very aware that you were in the other lane!
As for the performance, hmmmmmmm, don't know. I lived by the cahnge one thing at a time theory, it's the only real way to see variables other than full on electronic recording. Of which is what drove me out of drag racing, very good stuff, but very expensive.
As the night air cools, the air densty increases, the track conditions change, and your dial has to change accordingly, basic bracket racing 101. I'd say what is more important here is that you are happy with your changes, you have seen an improvement, looks as though you are on your way to setting firm your engines accessory levels, (i.e., changes), and ready to kick butt with reliable RT's, 60' times and good ET dialing prediction. That's what wins races, NOT continuing improvement, that's a persoanl goal. Reliable performance is tough to beat.
1/8th mile drag racing is tough racing so go out and fun!!!!!
lry99eldo

davesdeville
09-11-05, 07:00 AM
Times are a start but until there are dyno charts or at least numbers I'm not touching my intake system. For the corrected dyno numbers pretty much all external variables are figured in, not so at the track unless you're lucky and your local weather station is like a mile from the track like here in ABQ.

mcf1000x2003
10-07-05, 03:08 AM
I had a open element intake on my 95 STS and I noticed it got up alot better in the top end but i also noticed it got up slower in the low end .When I put my stock system in the low end was descent and the high end was normal I ran my STS at the track about a month ago and got 15.2 @ 93mph in the 1/4 mile with the custom open element air filter and it was a 99 degree day.I might go see what i can get next Wed. now that it is cooler i think the open element will have better low end.I also plan to try with the stock air box.

danbuc
10-07-05, 01:23 PM
mcf1000x2003, I'm sorry to be the one that has to tell you this, but your logic about how the open element air filter is better is extremely flawed. An open element filter will yeild much less power than your stock airbox, especially on a 99 degree day. Not only are you shifting your usable low end torque (which is what the car uses to launch off the line) further up into the power band, but your also sucking in 150-200 degree air from under the hood, instead of ambient air from outside the car. If you want a faster time at the track, with a better reaction time, run the stock airbox. If you want a slower time, and slower reaction time, than run the open element air filter. There's a reason they are called Hot Air Intakes. All they do is suck hot air from under the hood, which is THE WORST thing you can do if your trying to make power. Hell, even most Honda owners know this. :nono:

mcf1000x2003
10-08-05, 07:24 AM
I believe u that is why i still have my stock intake in. But I wanna find out how much slower it will be with and without it.It does make the car sound more aggresive which fools alot of people but i do notice a considerable amount of power in the low end with the stock air box.It sux for me cuz i like modding cars and it seems this is the only car ive had with very little power adders

lry99eldo
10-08-05, 11:20 AM
I think that in the case of the N* the engineers have done an incredable job to start with getting as much out of a 279 CI engine. And I think they went well beyond what the the aftermarket wanted to tackle let alone actually engineer that would improve anything well enough to attract buyers. Unless you have a set of drawings, a complete machine shop, tons of money, and OH, an SAE engineering degree, you have picked the wrong engine to mod up. Look at what it took Warren Johnson to do to an engine at GM to produce HP. He convinced them to create the DRC block as only a "foundation" to build on. I'd suggest going import for curing your performance needs. If I were still active in Drag Racing I know I would. A funny thing happens in life, ya get old and the World moves AROUND your meager existance, LOL!
lry99eldo

Mountie
10-10-05, 01:48 AM
Intesting reading about air intakes. I also happen to be swapping a Northstar into my '93 Black STS, at a Drag Racer's shop in Oceanside, Ca.


Personally, I wouldn't get to carried away on a minor modification to the air intake, except a bit better than stock filter. A lot of trouble (fun?) for a little difference.

One thing..........I don't suggest using an air filter that requires any oil substance on the filter! The oil can get onto the air sensor and screw it up!

Find a dry filter.

danbuc
10-10-05, 02:03 AM
mcf1000x2003, your car is OBDI. With enough money and resources, you could throw a turbo or supercharger in your car if you really wanted to. You would just have to get a chip programmed to adjust your A/F ratio accordingly. It's all abotu money though. A turbo setup for your car will cost alot to engineer. In all honesty thoguh, F/I is abotu the only real way your going to get any more usuable HP or torque otu of your car, other than freeing up the exhaust.

davesdeville
10-10-05, 04:53 AM
Only way to get noticable HP unless you spray it, that is.

powerglide
10-10-05, 03:45 PM
We spend alot of time running thermal/sound pressure/vibration/stress/flow analyses for many auto manufacturers. And, like many of you who's worked in the business knows, there's SIGNIFICANT money/time/effort spent on many of these parts. They are't designed and fabricated to look funny, every twist and turn design spec is based on good engineering reason. Sure its optimized to perform under variety of conditions but all in all, most parts are 'like that for a good reason'.

Some of the reasons are not very clear initially: for instance, if you fabricated the exact same shape of the intake box but used a less dense material. It will effect the stress, vibrations, sonic, and thermal response. (maybe even signifcantly)

WoodShoe
10-11-05, 10:18 AM
LoL..i love how a lot of people here praise the eng's on a job well done...then one day u go to remove something simple like your EGR valve, or change your rear brake pads even....the phrase "#$% :rant2: ^!@** :thepan: &% %$@* :bonkers: &*$$@# :banghead:" comes to mind ....

deepthinker22
09-16-09, 06:35 PM
too true

Submariner409
09-16-09, 07:26 PM
4 year old thread ??? Any further advice on intake tract work on a FWD Northstar installation ??