here's my thought process (which is likely flawed)
we all know one 2" pipe draws in more than two 1" pipes but bare with me here

these are completely irrelevant numbers only used for illustrative purposes

the intake takes in say 500g; the short ram air setup currently used allows the max airflow of 500g with a single short 2" tube
however after lengthening said tube the airflow will fall to say ~400g because the air has to travel a further distance through additional contours
but if you use two long 2" tubes the airflow should be back up to its maximum potential

I realize this is completely dumbed down and may not be entirely accurate but, the process seems to make sense in my mind
as I said I plan on making both anyway to actually be able to compare the difference in air temp, flow, turbulance, etc

 

two tubes splits flow. think about what you said.


the standard pettit intake is short and fat, It probably flows more air than you need.

 

Isn't a longer intake more beneficial to lower RPM because the air has more time to build up velocity? The higher the RPM, the shorter the intake should be because the length then starts to become a restriction. Of course, this is all still based on naturally aspirated mechanics. Add a turbine to the equation and I'm pretty sure you just need to supply the cold side as much immediate air as possible, as the turbine will pull in as much air as it's allowed to. As long as the flow across the MAF is stable, the less restriction and the shorter the intake, the better.


That being said, have you considered switching to a MAP based ECU at some point?

 

definitely more air than the TB can take it
thats why boring out the TB made such a difference imo

correct and in a perfect world yest I'd have the intake as short as possible but, to get cooler air from outside the engine the piping has to be lengthed
cooler air at the cost of flow but, thats where I was trying to compensate with dual intakes
in theory a larger panel filter/tubing would likely do the same thing


as much as I'd like to I don't have that deep of pockets and everyone says it will always cause problems

 

I beleive that that's the same principle the stock vfad uses. In slvrs case, he'd want more air for higher rpm as it's a track car. Low end torque isn't as necessary in something that won't see less than 5k with the exception of leaving pit lane.

slvr, if you want to test, just come up with some mock up setups and measure your maf readings. If you really want to get it right, you'd want an intake that pulls the exact amount of air that you can flow. That's a lot of leg work and trial and error though.

 

your intake might not be as much of a limiting factor as your maf. They can only meter so much air. If you start flowing more air than it can meter, you're gonna have a bad time.

 

Agreed. In B@W I advocated an intake like the Dodge Viper has stock. Short, runs straight to an box right behind an opening in the hood that gets moderately pressurize from forward speed.

Would need to pressure map the hood to make sure he isn't putting it in a low pressure zone of the hood. Neutral pressure is the lowest it should be, to avoid making the turbine work harder than it has to. The highest the pressure here, the less work is imposed on the turbine. The Viper's might actually be in a low pressure zone, looking at where it is, as low pressure forms right behind the leading edge of the hood, increasing the pressure as it moves backwards, to high pressure at the base of the windshield (where Grand Am RX-8 intakes pull from)

 

calling Cam now to see if they know the optimum airflow for the SC
I imagine the limiting factor is going to be the TB though

anybody know how many g/sec the stock TB is supposed to be able to handle?

I've got a series of tests I want to run concerning different intake setups that will really clear things up...just throwing everything out there to see what everyone's hypothesis is

like you said the low end isn't as important but, it does help acceleration and throttle response

 

I seriously doubt that the throttle body will be a problem with flow. I have crammed over 480hp through it without an issue.

The stock DBW throttle has issues though Mine seemed to be possessed at times...the ECU controls opening based on some parameters ( load?, temp? god knows what else) and can decide to close a bit on it's own. That has caused me more problems than enough....and we could see it on the dyno...almost like a limiter. Took the DBW throttle out and built a cable throttle and have loved it...car made more power with basically the same size throttle body..and the throttle response is much crisper. I used a throttle body off a Star Mazda race car...and the actuator lever is quite short...not much pedal travel from full off to full on

 

^^we don't all have an aftermarket ECU, if there is a work around for doing that with a Cobb AP and factory PCM we'd all love to hear about it

 

I never did find a workaround. Problem was I never did find a definitive answer as to what was causing the problem, and I couldn't do anything to replicate it either. ..so i did the easy fix and eliminated the damn thing

 

I've been studying it to try and figure out if setting up a mechanical TB to provide the PCM with the proper signals, but no actual TB feedback control, will still function properly

 

I have been looking at experimenting with my intake. My current intake is quite long and I seem to get a slight lag at low RPM. I also have a small filter which requires regular cleaning due to the lack of space behind the bumper bar.

I was thinking of creating a sealed box in the stock position and adding a large conical filter. I would also maintain the pipe behind the bumper bar to provide fresh air to the filter.

 

skc - the filter is likely where the most restriction is in your case

I've been thinking about aftermarket ECUs but, most of the teams I've talked to say to steer clear of them and aren't most of them ~$20,000?

 

The cost will largely depend on the development, target audience, and the feature list. My Hydra for my MSM ran me $2k, including $500 worth of sensors and supporting hardware. OMP control and injector staging are the two more uncommon features that you would need, though injector staging still isn't that rare and a PWM output could handle the OMP. The other factory ECU stuff that deals with intake valving and such isn't really a concern for you.

A full race Bosch ECU would run you that $20k, but I'd be surprised if there wasn't something far cheaper that would be entirely sufficient.


Be wary of negative opinions as much as positive ones, both are usually incomplete. Software for ECUs is always progressing, and plenty of the negative opinions out there on specific products are from people that dealt with a buggy version once, and are incapable of recognizing that later versions might actually be better. Hydra 2.1 and older was horrific, for example. Even as late as 2.6 was troublesome. 2.7 is really really solid. Still, people in the Miata community will rail against Hydra of any version as complete crap because of their 2.1 experience.

I expect that nearly every ECU out there follows a similar line of development. Really the same thing with flashing software like MazdaEdit. Growing pains are part of any software.

 

isn't pedal position the main factor in our TB opening
did you try just leaving the SSV open all the time?

 

The Hydra is a toy, not a real ecu.
Slvr just invest $6k in a motec and supporting sensors, lol. It should be enough...
Oh and screw having just 1 throttle body on a race engine. Start your build from the manifold.

 

I'm curious why you have that opinion, but I don't want to derail slvr's thread. Mind clarifying in B@W?

 

Bingo

 

I am thinking of using a polystyrene box to start the experiment and if it works I can look into something fancy later.

I have the stock plastic in place so hopefully the polystyrene will cope with the heat.

 

The typical polystyrene is not very strong or durable, but it's usually good to almost 300F/150C. Make it out of thin aluminum and then use dense foam to insulate it. They sell a nice dense foam that is very tough at home improvement stores here in the USA.

 

I think skc was saying he would use poly to make a box to see if there were any results and then build one out of alloy if he got the desired results like the one above.

Guessing you make that yourself team? looks like good craftsmanship.

Wish I knew how to weld.

 

I designed it, someone else fabricated the basic box for me, then I did the final fit up & installation

I can weld, what I need to learn how to do is lay carbon fiber


.

 

Nice, I wonder how strong the DIY carbon fibre is as you don't have the last process with the compressed air in a sealed bag. Probably strong enough for simple air boxes tho.

The german kosinonegg (mind my spelling) has over 400 cf parts YouTube it it's awesome.

 

Interesting to see some of the fastest rx8's around the world door bar designs




^passenger side, but I did verify in a video it was the same.