TOPIC: Further increasing the vacuum curve

Here's you guys a little bonus...

DISCOURAGE the use of "Cold-Air Intake" enhancements. Here's why...

Cold-air intake systems are ALL dedicated to allowing the engine to draw in more air. The theory is by easing the engine's ability to inhale, more air is available for the combustion of whatever fuel is available. Many reports of increased power support the theory, too.

The end result is the intake manifold pressure is higher, and the MAP system reads this, encouraging the computer to deliver MORE fuel, not LESS. Is that the direction we're trying to go with The Gadgetman Groove modification?

Absolutely NOT...

So, if a customer has a cold air installed on their ride, encourage them to reinstall the factory air box. This may cause them some concern, but once you explain to them the disadvantage when applied with The Gadgetman Groove, I am quite certain they will all agree to return it to stock, at least long enough to see the results!

Keep plugging, boys and girls. We ARE changing the planet.

One person and one engine at a time.

Ron

Hi Ron , I have a question, how much of the max. available air that can flow through the air inlet pipe does the engine actualy use. May sound like stupid question , but i have an idea to do something with the inflow of air before it reaches the t.body. I am refering to an engine with a grooved throttle body.......Greg P

(Rephrase the question) if an engine can idle on 1/8 inch hole plus what it can suck in from around the throttle plate, my plate has about 1/16 inch hole in the center of it from the factory. and the engine idles well at about 600 to 650 rpm. the diameter of the throttle plate is about 2 3/4 inches. (If the diameter of a pipe is doubled more than double the volume of air can pass through it) so if an engine can get enough air through a smaller hole , would it make sense to reduce the size of the intake hole , to get more vacume?

Ky, I don't know if Ron can answer this one.

You may be referring to volumetric efficiency, not exactly sure. VE may only be a calculation of flow starting at the throttle blade itself.

It's a complex question you ask in that that the absolute max. airflow potential would be at WOT under high load hi RPM. At all other throttle %'s and loads, the answer is some % of total airflow potential. Also relative to airflow potential of the given air induction tract. Variables abound--if I read you right.

Care to expand on this, whatcha got in mind here?

Tracy G

look back I rephrased the question.... Greg P.

Hi Greg...
Well ya coild try sticking a small piece of aluminum HVAC ducting tape over the hole and see what she does. Just a short test I would remove tape before it could come off. Try it and let us know how it responds.

Tracy G

Partially true, Cold air intakes can draw in more air, but at a greater restriction (they lower VE) that is why they are useless below 3000-4000rpm, beyond that they help by artificially increasing VE with sucking in lower intake air temperature (more dense air) which the 02 sensor sees, not the MAP. Another thing with longer intakes is the vacume pressure wave (think exhaust pressure wave, but in the intake) is more specific with longer piping, increasing VE again at specific RPM points, while a shorter more OEM style intake has a more universal (less drastic) VE increase along more points in the curve. There is couple more points to cover, but they tread the physics world with a lot of number crunching, did touch base a little the vacume wave, the vacume wave is what your seeing with the MAP, even then though it's not much, if it were such we would be seeing a VE of close to 100% which is theoretically impossible on a NA motor.

I'm sorry for the necro, but i like straight facts to be known and why it's not a good idea, if you want cold air and down low performance, build a real airbox to isolate your cheap circular filter

Medtactics wrote: Partially true, Cold air intakes can draw in more air, but at a greater restriction (they lower VE) that is why they are useless below 3000-4000rpm, beyond that they help by artificially increasing VE with sucking in lower intake air temperature (more dense air) which the 02 sensor sees, not the MAP.

You mean the MAF, don't you Ryker?

MAP, refer to OP. On any system effects will be the same regardless of MAF/MAP based system.

I'm not sure I understand, or if our understandings of how MAP and MAF data are interpreted by ECU are the same, Ryker. I'll need to do a refresh of that to make sure my brain is on the same page...or have the ammo to debate this

Also, if you don't mind, would you care to introduce yourself to this community so we can understand what you're all about, etc?

I was referring to how OP says cold air intake increases intake pressure that the MAP sees, which is entirely false, unless you have air charger. I was also referring to 1989 1.9L DOHC engine with a MAP and IAT, where 02 sensor determines fuel trim completely.

MAF is used to determine the mass of air available to determine how much fuel to use and injector pulse, in this setup the 02 sensor is merely used for minor corrections, or not used at all (diesel appilcations) while if equipped MAP ,still used to determine engine load for EGR and in some cases ign. Adv. And possibly injector pulse, depends on how vehicle is set up. MAP is not used for primary engine operation, but is there as a back-up for MAF failure, IAT is still used for ign. Adv.

MAP determines engine load by measuring vacuum, also for again EGR, and injector pulse, and ign. Adv., depending on a engne with no MAF that is.

As for I? I am just a simple performance enthusiast building a Perf Spec 190HP (124HP stock) NA powered 4-cylinder 1.9L that gets 50+mpg, it will compete in multiple race events, so if this mod does work performance wise, expect a bit of business and publicity in a year or so when it is completed and has participated in a few events, there is a build thread on the Saturnfans forum.

This is also why i am asking for the performance numbers, such as any dyno runs performed and the such?