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#1
Old 05-20-2005, 01:07 PM
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Turbo? Supercharge? Cold Air Intake? Leave it well enough alone?

I've been thinking about tinkering a bit with my '99 Alero GLS (3.4 V6) to get some extra "oomph" from the engine. I've read that the quickest, easiest, and cheapest way to do this is to install a cold air intake with a K&N filter, and that this (in theory) will give a slight boost in horsepower and fuel economy. Has anyone tried this (with any car, not just an Alero)? Can anyone tell me how it compares to the effects of a turbocharger or supercharger? Any other ideas of how to get the most bang for my aftermarket buck?

Also, has anyone used the "Turbonator"?
#2
Old 05-20-2005, 01:28 PM
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Cold Air Intake - $100 or so. Most likely won't give any extra power at all, as most modern cars have pretty good intake systems. Could get you 2-5HP though, and slightly better throttle response. Most people won't even notice it (other than being a bit louder)

Turbo - Very expensive (probably a couple grand to do it right), very difficult, likely would require professional installation unless you are pretty darn experienced. Can give lots and lots of power, anywhere from 30HP to 100HP, but could also destroy your engine if not done correctly (engine managment, injectors, etc.)

Supercharger - About as expensive as the turbo, a littel easier to install (if there is a kit for your car), doesn't usually provide quite as much power.

Turbonator - ripoff, crap, scam, etc.


There really isn't a great deal you can do to cheaply give yourself much extra power. Intake could help throttle response, a free flowing (and thus louder) exhaust can give you a couple of HP. From there you are talking forced induction, or major engine internals work.
#3
Old 05-20-2005, 01:31 PM
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Hmmm. So what about the claims I've heard about getting some benefit from simply using a K&N "performance" filter and not even installing a cold air intake unit? About the same difference as the cold air intake, or what?

Kinda figured that the Turbonator was a scam...
#4
Old 05-20-2005, 01:56 PM
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Quote:
Originally Posted by Cuckoorex
Hmmm. So what about the claims I've heard about getting some benefit from simply using a K&N "performance" filter and not even installing a cold air intake unit? About the same difference as the cold air intake, or what?
Pretty much. There are lots of little things you can do to add a small amount of horsepower, but to make the car noticably faster you're going to spend some time & money under the hood. You'll notice the price long before the performance, so it's probably not worth it for daydreaming during the rush-hour commute.

There's alot of things people say that will "add 50 horses and 50 torque" (similar to the Turbonator mentioned above). They're usually said by people with "Type R" and "NOS" stickers attached to their Dodge Neons so take that as you will.
#5
Old 05-20-2005, 02:33 PM
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I installed a K&N intake on my Xterra and it made the throttle response better, and the overall performance seems to be improved especially at higher speeds, but don't expect it to give you a huge horsepower boost. The gas mileage might be better with a drop in K&N filter but with an new intake it will certainly go down. More air=more gas=less mpg.
#6
Old 05-20-2005, 02:43 PM
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I have installed a K&N on my last couple of cars, mostly because it is a high quality filter that can be cleaned and re-used. But I never noticed any real difference using it at all.

Cynical Optimist 's comment about NOS stickers above reminds me:

A cheap way to get a ton of power (though short lived) is to install a nitrous oxide system. Gives a quick fast temporary boost, though if not properly installed, and abused could damage the engine or shorten its life. But if you are dead set on finding 50HP cheaply, that is the way to go. Just adding the sticker, however, does nothing
#7
Old 05-20-2005, 02:49 PM
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I'd be careful with the K&N filters, myself. Sure, they flow more air than the standard paper ones, but they also flow more dirt and crap into your engine as well.

Plus, the oil can come off and crud up your MAF.

At any rate, you're probably only talking about maybe 8 hp from a K&N and cold air filter box.

Probably your best bet for giving it real power and torque improvement would be to see if someone makes an aftermarket tuning chip for your car/engine. a few companies(but not all) that make these are: Diablosport, Superchips, Jet Chips

Those usually see something like 15-20% torque improvement and 10-15% hp, as well as better gas economy. They do this by moving your spark pulses to different spots in the cycle, changing the injector pulse width and timing, and other things to optimize the power of the engine.

The main caveat is to gain these improvements, you have to run premium gas. But... with gas prices as high as they are, the percentage difference between regular and premium is smaller than it's ever been (~10% difference), so it's actually not such a bad deal.
#8
Old 05-20-2005, 03:02 PM
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Your car probably already gets cold air once it's warmed up. The device that pulls in preheated air from a "stove" on the exhaust manifold only works when the engine is cold.
#9
Old 05-20-2005, 09:57 PM
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My neighbor has a Ford Ranger pickup with a 5.0 HO Mustang engine in it, and he swears by the K&N cold air intake he installed on it. But he also installed true dual exhausts with Flowmaster "mufflers" and no cats, tubular exhaust headers, a Granatelli throttle body and MAF sensor, MSD ignition module and distributor, and a hi-lift camshaft. I think the (significant) increase in power he experienced is due to a combination of all the systems, because the benefits of improving one system are limited without also improving the others. That truck is scary fast, BTW.

I considered installing the K&N cold air intake on my truck (Chevy Silverado), but it has the 5.7 liter Vortec engine, and the intake is a critical component of the Vortec system. I'm skeptical about being able to easily improve upon a system designed by highly experienced and talented automotive engineers who have access to computer-aided design tools. It seems to me that they would have designed the engine to be as powerful and efficient as possible (or practical), straight out of the box.

bump - As far as trusting K&N filters' performance goes, I wouldn't hesitate to use them. The crewboats I used to run had K&N filters on their 1200 HP 16 cylinder diesels, and these engines ran almost 24 hours a day, mostly under full throttle, without any failures caused by poor air filtration. But you are absolutely correct about excess filter element oil fouling the MAF sensor on gasoline engines. The oil is intended to be used sparingly.
#10
Old 05-20-2005, 10:22 PM
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There's an old axiom in racing circles: Speed = Money.

The only question that remains is: How fast can you afford to go?
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#11
Old 05-20-2005, 10:51 PM
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Good luck finding any performance products for an Alero. I doubt there's very much market for them. If you get a K&N filter, remember you have to clean and oil it periodically, and they stop less dust than a regular air filter.
#12
Old 05-20-2005, 11:29 PM
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My non-expert "street knowledge" on the matter is that unless you are a ricer or some other type that is willing to go into this eyes-open, knowing it will cost a ton (ie. you don't car because have your heart set a look or certain sound, or you just love that particular car), you always are better off in time, hassle, and cost selling and simply buying a faster car than you are overcapitalising on aftermarket stuff that will quite possibly damage the resale value of your car, and will also possibly do bad things to the car's balance and handling. Ya don't install the go-fast toys without doing likewise with the brakes, suspension, etc.
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#13
Old 05-20-2005, 11:47 PM
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Quote:
Originally Posted by mike1dog
Good luck finding any performance products for an Alero. I doubt there's very much market for them.
Well, I've been able to find performance chips, cold air intakes, performance air filters, headers, etc. It probably helps a bit that the Alero shares the drivetrain of the Grand Am.

I'm really not looking to race the thing; I'm just looking to get the most out of the engine without wrecking it or spending thousands of dollars. I agree with the poster who said that if I really want significantly better performance, I'd probably be better off just buying a faster car instead of trying to add aftermarket stuff.

The idea of adding a turbo or supercharger was just something that flitted through my head, but upon further reflection, I don't think I would ever install a turbocharger or supercharger in the thing anyway; for one thing, I'd be worried that my automatic transmission would be beaten into submission.

I think at first I'm just going to try out the K&N drop-in air filter and see if that makes any difference. That's probably the cheapest and least risky route to take. (least risky? Is that correct english?)
#14
Old 05-21-2005, 04:58 AM
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Quote:
Originally Posted by mike1dog
and they stop less dust than a regular air filter.
What is the basis for this statement? I was under the impression that an oiled filter stopped more dust than a dry paper element. Since the oil is part of the barrier, very tiny particles are trapped in suspension that would pass straight through the pores in a paper element filter.
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#15
Old 05-21-2005, 11:53 AM
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Quote:
Originally Posted by NillyWilly
There's an old axiom in racing circles: Speed = Money.

The only question that remains is: How fast can you afford to go?
Actually the quote is Spped is a function of cubic money. How fast can you afford to go?
#16
Old 05-21-2005, 01:08 PM
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- - - One thing you can do safely is get lower-profile tires put on the wheels you've already got. This kicks up accelleration a bit, and improves side-to-side handling as well, it is surprising what a difference in overall sportiness feel it can make to a car. Your speedo and odometer will run a bit high unless you get that corrected at a speedometer shop, but it's not critical. And there is a increased risk from road damage, some engine-noise increase, and a slight MPG and top-speed decrease but it is the most practical "upgrade" for most cars, considering they way they are typically used. Most regular people never know what the top-speed of their car really is, for example--so losing a bit off that number is really no concern.
- The high-flow intake filters do help a bit and are safe to do, if you maintain them.
- Turbos and blowers will accellerate wear on your (otherwise stock) engine if you turn them up a lot, but they are expensive, and so it doesn't make much sense to install either just for a few-percent increase in power.
~
#17
Old 05-22-2005, 02:14 AM
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Quote:
Originally Posted by DougC
- Turbos and blowers will accellerate wear on your (otherwise stock) engine if you turn them up a lot, but they are expensive, and so it doesn't make much sense to install either just for a few-percent increase in power.
I'd say that aftermarket turbo or superchargers add more than a few percent increase in power but I agree that there's not really any low-risk, low-buck and meaningful performance upgrades for most vehicles. The hop-up chips might be an exception but you'll really want to do some research first.
#18
Old 05-22-2005, 07:27 AM
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Remember that a more powerful engine, however you make it, only helps if you've already got it floored. If you don't already spend a lot of time with the pedal to the metal, just grow a heavier foot. It's a lot cheaper than any aftermarket item.
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#19
Old 05-22-2005, 08:56 AM
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Quote:
Originally Posted by Madd Maxx
I installed a K&N intake on my Xterra and it made the throttle response better, and the overall performance seems to be improved especially at higher speeds, but don't expect it to give you a huge horsepower boost. The gas mileage might be better with a drop in K&N filter but with an new intake it will certainly go down. More air=more gas=less mpg.
Why do they claim that the K&N filter increases gas mileage? You typically cannot increase both potential power and potential economy unless you increase engine efficiency, in terms of:

* mechanical
* thermal
* combustion

Pumping or volumetric efficiency, which is something controlled by intake and exhaust processes, generally only leads to an increase in potential power, unless the engine is already so poorly designed that flow stratification is causing mixture problems and impacting combustion efficiency. I sincerely doubt a port fuel-injected post-1980's vehicle has those issues.

So how exactly do they claim to increase efficiency?

FTR, with respect to power increases - they're talking about cases where there *may* be a "2-5 hp increase" at peak power - generally, this is going to be at 5000+ rpm. At lower speeds, the proportional power increase is going to be much less, and also at lower speeds conventional intake systems are better tuned, so the proportional increase is even less. I would be highly surprsied to see a drop-in K&N filter increase power by more than 1hp in normal driving ranges.

Also FTR, when we did dyno testing at university and had people test whether or not they could perceive a power increase, we found that with a Buick 231 in a Skylark, that you needed nearly a 10-15hp increase (at peak) before performance was even noticeable. And that was not reliable.

I suspect for anyone except a hard-core racer, the only effect of a K&N filter in a modern, well-tuned FI car is going to be pure placebo. I could write for hours about placebo effect testing on cars with magnets on the fuel line, special oils, fuel additives, etc., but there's no point because people will ignore all scientific evidence and still go with the placebo because it's a quick fix that makes them feel better.

This is very important, IMO:
Quote:
Originally Posted by TheLoadedDog
My non-expert "street knowledge" on the matter is that unless you are a ricer or some other type that is willing to go into this eyes-open, knowing it will cost a ton (ie. you don't car because have your heart set a look or certain sound, or you just love that particular car), you always are better off in time, hassle, and cost selling and simply buying a faster car than you are overcapitalising on aftermarket stuff that will quite possibly damage the resale value of your car, and will also possibly do bad things to the car's balance and handling.
To add to this - if you want a fast *new* or *newer* car, one is going to have to bite the bullet and just buy a faster car to start with. When I bought my Mustang GT, people in the office said things like "Oh, that's going to be too much power for you" and "You won't feel comfortable with that much power" and "Why not save $3000 and get the V6, then upgrade it with K&N filter, Slick50, etc. You'll get just as much power", which, of course, is unmitigated donkeyshit. So many people cut costs and don't go for the best engine option, or choose a car they didn't really want because "well, the wife/husband/concubine/parents want me to get something else", then waste hundreds of dollars chasing snake oil performance boosters, or multiple thousands modifying the car to the point where it's no longer reliable and driveable (people told me I should get the V6 and add a $3000 supercharger, rather than just spend $3000 more for the GT...so I can get a new car and void the warranty and destroy the reliability on it hacking the engine with a finicky supercharger kit so I can get...about the same power and torque as the GT. Hmmm...)
#20
Old 05-22-2005, 10:08 AM
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My basis for sayin K&N filters stop less dirt is personal experience. At the dealership where I work, I've seen several Ford turbodiesels brought in that have had wrecked engines because of dust inhalation. Almost all of them had K&N filters on them. Here"s a good report on filter efficiency.
#21
Old 05-24-2005, 10:55 AM
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OK, I dropped in a K&N hi-flo filter and...

Well, the car runs pretty much like it did before. No real difference that I can tell. Oh well.
#22
Old 05-24-2005, 06:25 PM
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Quote:
Originally Posted by Una Persson
<snip>Pumping or volumetric efficiency, which is something controlled by intake and exhaust processes, generally only leads to an increase in potential power, unless the engine is already so poorly designed that flow stratification is causing mixture problems and impacting combustion efficiency. I sincerely doubt a port fuel-injected post-1980's vehicle has those issues.<snip>
I agree with almost all of your post. On my particular truck however there was miles of tubing that was part of the intake system that was actually a drag on the engine. Acceleration wasn't as crisp as the air had to travel further and in no way straight before reaching the MAS, and ultimately the ports themselves. I ended up taking out half a dozen peices of plastic tubing that were part of the stock intake, some of which are shown below and replaced them all with two straight plastic tubes with a silicon sleve between the two. You can check out some of the before and after pictures here NissanOffroad.net, click on "How To Guides", Frontier/Xterra, Airbox modification or K&N.

Note: I am in no way affiliated with this site at all, its just one I frequent when having problems with my vehicle.
#23
Old 05-24-2005, 09:14 PM
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OK, maybe I spoke too soon. The old Alero does seem to have a little more pep, which is especially noticable when accelerating from 30-50 mph; at the very least the engine response seems smoother or more consistent. Maybe it's just a placebo effect, I guess. Unfortunately I didn't test the Alero's acceleration times prior to the installation of the K&N filter, so I can't prove that performance has improved. It sure feels like there's at least a slight improvement.
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