Air Intake, Any suggestions Options

[aveale]

While poking around E-Bay between patients, I noticed a listing for an Cold-Air Intake for the D-Jet.

http://cgi.ebay.com/ebaymotors/ws/eBayISAP...&category=38634

I have used them in my other car with noticeable improvement in engine pickup.

Anyone have any 914 success with these lately?

T

[Bleyseng]

Do they have any dyno charts to back up their claims, I wonder why.

If you remove or replace witha K&N air filter you get about 1 hp over the stock filter.
There have been tests running a cold air pipe to the aircleaner snorkle that helped by 1 or 2 hp. This pipe goes right to the fresh air grate by the battery or driverside to catch cold air for the motor vs the hot air in the engine compartment which the other $99 unit will suck in.

Geoff (IMG:style_emoticons/default/wink.gif)

[Brett W]

Looks like 15 dollars worth of Home Depot hardware and a 50$ K&N filter. Peice of cake. The 1.7-1.8 is a peice that is avalaible for VW mass air cars. Not worth 100$ bucks.

[dmenche914]

Have not used one before, however. The 914 unlike a "conventional car" probably needs one less. The intake is in the engine bay, which is flooded with cool air, as all air flow for engine cooling is top down. (assuming all your rubber engine seals are in place) So the air intake is already in front of the enigne, not behind it. It is already getting cool air above teh motor in the air stream. In a conventional car, the stock intake is often above the engine also, but trapped under a solid hood, and sucking hot air since it is behind the radiator, cacthing hot air from the air flow.
The cool air systems on a conventional car simply move the intake to infront of the radiator. In the 914, the stock design is essentailly that. True it is a bit cooler outside the engine bay, however the improvement you would gain might not be noticable like it would on other cars. (and who wants a hole in the engine lid for an external from engine bay filter unless you have a track car)

There are higher flow filters, however if you are still running a stock injection system, keep the filter stock. If you get rid of the stock filter, you loose hoses that provide crankcase breathing, and gas evaporative control both of which are good things to have. You will have a cleaner engine, less oil leaks, and be less polluting. m For many with a stock engine, the stock filter works fine, the factory didn't design an overly restrictive system.

Aftermarket filters can make your car seem faster, as they usually change the noise a bit louder, hence you think you go faster. You can do the same thing with a noiser muffler, without the problems with breather and evap hoses.

If you have an early 914 with the oil bath filter, you can upgrade to the stock later paper filters, which many folks like better, maintainance is easier, and in hard corners, the oil has sloshed out. I do not mind them too much, but heck I grew up on old VW's with the same oil baths, framiluarity breeds foundness I guess????

if you have upgraded to carbs, and require greater than stock air flow, there are many brands, with K and N being popular (I have one on a Buick powered 914) too choose from. As with the Stock FI, on carbs you still need to provide for crank case breaters to the filter, and it is nice for the air to hook up the stock gas evap system it does not cost ANY horsepower or effect drivability at all, and gas fumes from the tank are a BIG contributor to the smog from a car, even when parked. Most carb filter kits leave it up to you to figure on how to connect the hoses, (ie you need to make the fittings, they ain't there) but that does not mean it should be overlooked.

I personnally with a stock engine, would leave it stock, avoid oil leaks, keep emmisions low, and the noise lower, Intake noise is annoying to me, but I for some reason sure love the sound of a Bursch exhaust.

good luck

[Demick]

Have not used one before, however.  The 914 unlike a "conventional car" probably needs one less.  The intake is in the engine bay, which is flooded with cool air, as all air flow for engine cooling is top down. (assuming all your rubber engine seals are in place)  So the air intake is already in front of the enigne, not behind it.  It is already getting cool air above teh motor in the air stream.

I beg to differ. The stock intake location is in a horrible location and air is preheated by as much as 60 degrees F.

TEMP TESTS AND COLD AIR INTAKE

Demick

[dmenche914]

Most I have measured at speed is 15C rise above ambient or about 30F. This is less than one would find on a conventional car under the hood above the engine, behind a radiator. Thus like I said, the effect of adding a cool air intake would be less on a 914 than a conventional car. Nothing to differ about, I think we are on the same page. No doubt however that 60F rise is possible, certainly when car is moving slow, and likely also if there are leaks in the engine bay seals. even different motors may run different. My guess still is air on a conventional car after passing thru a radiator, on top of a motor is hotter than 30 or even 60F above ambient. The 914 intake is in a better position than other cars that get air from the radiator waste air. The question is the gain worth the effort, and loss of breather/evap hoses unless effort is made to hook them up? On a stock engine, I believe the gain is not worth it, however worth it is all relative, maybe to someone else it is worth it. Yes power can be gained, even with modest temp reduction.

There are tables written in internal combustion texts that will give percent power change with air temps, does anyone have access to one, and can share it?

[Demick]

Most I have measured at speed is 15C rise above ambient or about 30F.

I'd be willing to bet your measurements were taken without a rain tray. Am I right? The rain tray makes a big difference because it essentially forces the cool air to bypass the stock intake snorkel.

Demick

[Mark Henry]

I beg to differ. The stock intake location is in a horrible location and air is preheated by as much as 60 degrees F.
Demick

I have to agree with Demick.

My SDS intake sensor gives me a real number on the controller and that's right in the ballpark.

I've seen tha pics of that intake...you can make it yourself with parts from Home Depot and crappy tire for less than half price...in Canada maybe even a 1/3 of the price.

[dmenche914]

Would the snorkle hook up to the stock filter, or would it replace the stock filter withh other? If it is just a snorkle that attaches to the stock filter, then it starts to become in the worth it catagory, as the stock filter breather, and evap system does not have to be redone.

[Demick]

Would the snorkle hook up to the stock filter,

Mine does. But there are lots of ways of getting cool air to the intake. My webpage shows one way, and was designed around some autocrossing rules as well as the need to have it completely waterproof. Other people with different needs may come up with a different or more suitable method.

The main point is that the stock snorkel location is suboptimal - especially if the rain tray is installed.

Demick

[dmenche914]

Just saw your website, nice snorkle, good data to prove it. yes, the rain tray probably makes a difference also!

Good set up, paint the snorkle black, and I bet you could sell them as fast as you make them, especially with the data that proves its worth.

nice!

dave

[anthony]

Demick, I would have liked to see your tests with a stock snorkel and the rain tray removed.

[Demick]

Dave: yes, mine is now painted black. I made that web page at least a couple of years ago. It provides general instructions on how anyone can make their own - I have no interest in trying to sell it. Many people have different requirements or want to improve on it anyway and will build themselves something slightly (or largely) different.

Anthony: No I didn't take any data with the rain tray removed. But I wouldn't be at all surprised to see the temps drop in half from what I measured.

Demick

[3d914]

Demick,

Nice job on the snorkel! I'm surprised that this is the first I've heard of it. If you find imitation the highest form of flattery (IMG:style_emoticons/default/pray.gif) , I'd like to take your idea a step further and have an opening on each side - one on the left (as you have) and another on the right. Just want to get more air in there.

What do you think?

[Demick]

Gerard:

Most important thing is controlling where the air comes from. My snorkel already has a cross sectional area of over 4x the original snorkel, so it is already way overkill in that respect. And remember, it all gets sucked down a pretty small diameter throttle body. So personally, I wouldn't bother with the dual sided intake. I don't think there is anything to be gained.

With the rain tray installed, there are 3 places to get cool air: at the right and left sides of the engine compartment, and near the foward firewall of the engine compartment. Pick a location and go with it.

Demick

[airsix]

I beg to differ. The stock intake location is in a horrible location and air is preheated by as much as 60 degrees F.

I agree. And like Mark I get an intake temp measurement right off my ECU. I've seen my intake temps reach 74 degrees above ambient!*

-Ben M.

*I should probably mention the 12psi boost and no intercooler. Boost is back down to 10psi and I'm working on an intercooler.

[Cap'n Krusty]

If your satisfied with FAR fewer square inches of filter area, with MUCH larger pores, and degraded filtration, K&Ns are the way to go! The Cap'n