XelderX's Intake Porting

[xelderx]

Xelderx, what you described, is a loss in throttle response. When you're at part throttle and mash it, the time it takes for the engine to build power is throttle response. What I believe has happened is that you've lost velocity. You may not realize is, but for any given speed, you're probably deeper into the throttle at any given time.

As long as you're enjoying driving your car now more, is all that matters though......

Nah..it's something else. When I press the gas from no throttle input to WOT it has no hesitation no matter if I start from idle or 4,000 RPM. If the throttle response is lacking the hesitation would be felt if I was cruising at any RPM with any throttle input and went immediately to WOT and the car did not respond instantly. It doesn't act like that. If I'm cruising around say at 4,000 RPM where the gains are really starting to be noticable and I slowly push the throttle in the car will seem to fall off in torque. It's still accerlerating, but not at the rate it should be. I think saying it was hesitating was the wrong description. Best I can figure it is dumping a little too much fuel and going rich. As long as you make the throttle inputs forceful and quick it doesn't happen.

 

[Captain KRM P5]

I'm still stuck in the grassroots racing ideal and I like to do everything I can by myself. It makes the improvements all that much more enjoyable. So how about the N/A tuning info on that Haltech?

if matty covers my trip down there i might be able to figure that out a little bit for you

 

[PR5Matt]

I'm not exactly sure where your theory comes from, but all "theories" of head porting have been proven many times over. Just because it's a 2.0 Mazda motor doesn't mean that the theories on porting have to be relearned. You are not " finding the limits" you are ruining an intake manifold and head.

Your theory of the "improved velocity" from VTCS removal is also wrong. The air is not gaining any speed because you took a object out of the path. You increased flow by removing the object. Now by opening only a couple of inches up you have created basically a resonance chamber for all sorts of turbulance to occur, also decreasing velocity.

Now that I sound like a complete jerk...

I suggest researching the subject intensely, then find your local performance engine builder and ask him what he would do with it.

Dude! There are f**K'n flapper plates at the ends of the intake runners! Take 'em out!!!!

 

[xelderx]

Dude! There are f**K'n flapper plates at the ends of the intake runners! Take 'em out!!!!

He was saying the right things and his theorys are sound. I don't think what happened on my setup though, can be called a resonance chamber. The larger port that I created from the manifold to the head sounds like it created a small area where the runners get drastically bigger, then enter the head where they get drastically smaller before reaching the valves. I actually found that while the intake runners did get a lot bigger right before the entrance to the head, the porting job on the head didn't create a large opening that tapered down to a small one. The head now is actually pretty much a straight shot to the valves. I don't think I created a resonance chamber so much as I just madethe one that was already there a little wider and longer.

Instead of this <> shape in the airflow from the mani to the valves...I have the progressively increasing "v" followed by a straight path that maintains the the volume rather than decreasing it again.

 

[xelderx]

My friend Loi and I had a good discussion today concerning my cars "hesitation" at partial throttle opening. I think we have it figured out. I think the car is going too lean at partial throttle openings due to the ECU being in closed loop. At WOT the ECU goes into Open loop and dumps more fuel which is why I can't feel the problem as long as the throttle is pinned. The Open loop is keeping the car from leaning out. Now I need to figure out how to get more fuel in there while in closed loop. I know that any standalone or piggy back ECU could easily handle this. My friend Loi mentioned that a RRFPR might be reasonable temporary fix until I can save enough for a piggy back, but I'm really not wise to how those things work and i know that they are the cheap way out when it comes to turbo cars. Any thoughts on this?

 

[Captain KRM P5]

My friend Loi and I had a good discussion today concerning my cars "hesitation" at partial throttle opening. I think we have it figured out. I think the car is going too lean at partial throttle openings due to the ECU being in closed loop. At WOT the ECU goes into Open loop and dumps more fuel which is why I can't feel the problem as long as the throttle is pinned. The Open loop is keeping the car from leaning out. Now I need to figure out how to get more fuel in there while in closed loop. I know that any standalone or piggy back ECU could easily handle this. My friend Loi mentioned that a RRFPR might be reasonable temporary fix until I can save enough for a piggy back, but I'm really not wise to how those things work and i know that they are the cheap way out when it comes to turbo cars. Any thoughts on this?

they are not a cheap way out. thats a tired myth that should be put to rest. RRFPRs are used in many race and street applications, including top fuel drag cars, superchargers and turbo kits. BEGi sells these things by the bucket load and have been refining the design for two decades now. the rising rate regulators (a trademark design BTW) are not like the single setting "12:1" vortech FMUs which you might be thinking of. to be honest i had more consistent and smooth air/fuel ratios on my wideband with the BEGi RRFPR than initially with the haltech.

rising rate regulators not only can have a base fuel pressure adjusted, but thier rate of gain can be adjusted as well. it will add fuel at that set rate of gain from that base pressure based off of vacuum or pressure in the manifold. my experience with RRFPRs is that they are very easy to install and tune. grab a decent fuel pressure gauge and a wideband and you're in business. no messy wiring, no tuning, etc. of course you are limited in what you can do with an RRFPR but for your application it might be worth a look.

i would shoot an email to corky@bellengineering.net and get his advice. his knowledge is unparalleled and he is very willing to share his insight when asked.

of course if you had the money i would say haltech e6x or microtech standalone and do the whole shabang

 

[xelderx]

Thanks man. I really want to go ahead and get the Haltech and be done with it, but right now there are so many other things that the car needs a lot more for this year (roll cage, LSD, new wheels/tires). I'll email Mr. Bell and get his opinion.

 

[igdrasil]

xelderx

What I believe your problem is that you removed your VICS. You will loose too much torque down low because those flappers when they are open is like having a shorty manifold, which is good for high rpm only...thats why you have good high end.

You need to keep the long runners for low rpm torque.

 

[xelderx]

xelderx

What I believe your problem is that you removed your VICS. You will loose too much torque down low because those flappers when they are open is like having a shorty manifold, which is good for high rpm only...thats why you have good high end.

You need to keep the long runners for low rpm torque.

I still have the VICS in the manifold. I removed the VTCS which are the butterflies right at the head. I also noticed tonight that a WOT pull from a dead stop will put out a lot of black smoke. Open loop must be dumping a shitload of fuel.

 

[flat_black]

Black smoke from the hole on WOT? Damn... When I go WOT from a dead stop, the car just spins the tires through the first two and a half gears, and I get no black smoke. I wonder why it would dump in more fuel in your case, though... What ECU are you using?

 

[igdrasil]

I dont know how the open loop triggers on the MP3 ECU, but you already know what black smoke means...poodles of fuel. hehehe

 

[RyanJayG]

xelderx

What I believe your problem is that you removed your VICS. You will loose too much torque down low because those flappers when they are open is like having a shorty manifold, which is good for high rpm only...thats why you have good high end.

You need to keep the long runners for low rpm torque.

I wish this were true, but the VICS does not open up short runners. It simply changes the volume of the intake plenum (basically). Some people have talked about drilling or machining that chamber into the main plenum, so there would be a shorter path of air when the VICS is open.

as for the VTCS being removed I can think of no ill effects power wise. its only there for cold start emmisions.

remember that no MP3 or J-spec 2.0L has it.

 

[xelderx]

Black smoke from the hole on WOT? Damn... When I go WOT from a dead stop, the car just spins the tires through the first two and a half gears, and I get no black smoke. I wonder why it would dump in more fuel in your case, though... What ECU are you using?

I'm running the MP3 ECU

 

[RyanJayG]

I'm pretty certain that at WOT (atleast with quick changes from normal throttle to WOT ) the ECU goes open loop, which on the MP3, just like the other protege ecu's is way rich, even for your improved airflow.

 

[xelderx]

I'm pretty certain that at WOT (atleast with quick changes from normal throttle to WOT ) the ECU goes open loop, which on the MP3, just like the other protege ecu's is way rich, even for your improved airflow.

Yea...I think thats what I'm running into. It's also warmed up a little in the last few days and the closed loop hesitation is not as bad. I'm assuming due to the warmer intake temps richening up the A/F a little. Also I washed my car yesterday and the soot on the rocker panel was hideous.

 

[twilightprotege]

mine only goes into open loop at around 3800rpm @ wot. before that at wot it stays in closed loop.

 

[xelderx]

mine only goes into open loop at around 3800rpm @ wot. before that at wot it stays in closed loop.

I don't think I'm having any trouble below 4,000 RPM so I'm not sure if the A-spec ECU's operate the same way. Also in my RRFPR thread you metioned that the ECU is reading from the o2 sensor while in closed loop. Does it read from the 1st, 2nd, or both o2 sensors to adjust fuel?

 

[igdrasil]

it will read both sensors, maf, ait and ect

 

[igdrasil]

I wish this were true, but the VICS does not open up short runners. It simply changes the volume of the intake plenum (basically)

What I meant was that those flappers open the secondary plenum along with the seconday runners, thus having a larger area and a "short path from the plenum".

That is like having a short runners intake manifold...good for high rpm, lower inertia.

 

[xelderx]

it will read both sensors, maf, ait and ect

Ok so it reads both sensors, but does my MIL eliminator effect the way the ECU gives fuel. I don't think it would effect it enough to create drastic changes in the ECU's fuel delivery....I'm just trying to understand what the ECU is doing.