Custom built Venturi intake, using garbage scraps

Ok, First of all, I'm just some poor ass 21 year old kid trying to make his car kinda nice, had shitty grades in highschool, don't expect a masterpiece.

I used the following parts:

-3" Anodized aluminum pipe off a broken telescope (now brushed finish)

- ABS plastic port tube off a broken subwoofer

- Random corroded copper scraps I found in the back yard




So this idea started off like this:



I was cleaning the workshop/basement area and found a broken anodized aluminum telescope. I noticed the little part in the middle and it made me think of the venturi effect.

I then talked about it with my mechanically inclined friend who said there's no way I can just make a Venturi intake just like that.



I drew this retarded schematic on my phone while talking about it, you guys probably think I'm an idiot by now lol.





started cutting the pipe



Pipe is cut to size






This was the corroded copper scrap.



Port tube off a subwoofer



Checking fitment



I spent a long time grinding, filing, and polishing this corroded pipe.



more checking fitment



drilled hole with a 3/8 bit and filed it to about .75" to get the pipe to go through, then drilled and filed a slightly smaller hole in the port tube to get it to barely fit with a seal.
also made it a brushed aluminum finish.




looks more like the schematic now






fitment again



I'm using gorilla tape and the rubber of my current intake system to serve as a retention mechanism to keep the copper pipe in, which works great actually, I will eventually epoxy it together when I have more time




almost done.








Finally put in the car.


A few things: I already know I'm going to get shit because it's 3", but I don't have a supercharger, so I don't need the 4" intake until I get one. Also, everyone is gunna say the venturi intake is stupid and won't work, but I can gaurentee you that it DOES work, and improved speed slightly, but more importantly, the throttle response is WAY better.


Also, note: they don't even make kits for the Riv, and I made this literally out of shit that should've been thrown away but hasn't been yet. I spen't $15 total on the intake, for a clamp and 90 degree rubber elbo that was part of my old intake.

Nice work man! You should post a video, I'm curious to how the intake sounds. Also can you explain how exactly it works using the venturi effect?

Props! hey if it works right! I'm waiting till I figure out how to make it cold air...
It gets hot under the hood.

RidzRiv wrote:

Nice work man! You should post a video, I'm curious to how the intake sounds. Also can you explain how exactly it works using the venturi effect?

Thanks

and my riv isn't supercharged, plus my speedometer is broken, not accurate

Basically, the funnel, smaller tube at the sloped angle allows air to be forced in faster because of the copper pipe that allows the air to difuse, not constricting airflow, but making it swirl and go faster. it's the difference between a bic lighter and a mini torch lighter, literally. same principle but much smaller

gmann3001 wrote:

Props! hey if it works right! I'm waiting till I figure out how to make it cold air...
It gets hot under the hood.

I have a plan for a cold, true ram air intake when I have enough funds for a supercharger.



when I repaint my car, I'm going to make a new 4" (possibly venturi) intake and make a scoop that looks like that out of aluminum and weld it to the hood among other things, and have a heat shield that forces air into the ram that goes into the intake system/supercharger.


Then again, most riv enthusiasts would flame the hell out of that idea. lol

okay so this has been happening for months now. My step dad says it's all in my head, but it's really starting to piss me off now.


I recently have freshened up all the fluids, put a new short hot ram intake, cleaned the throttle body with carb cleaner, then even built a custom venturi intake, and nothing really helps low end speed much

except one thing slightly helped. the one thing that should've never made my car faster.



When I first put in the Venturi intake, it was backwards, I guess I had a huge dyslexia moment. it made the car slightly faster and improved throttle response, so I thought all was well, until my friend asked how it worked, then I realized that it was in backwords. I then re configured everything hastily anddidn't secure it well enough, and I geuess it fell out pretty much instantly, then I drove it about 2 miles, not noticing an improvement from before, confused. I then went in a gas station and popped open the hood and realized it fell out, then secured it better, and to my dismay, the car wouldn't even start very well. if I revved it, it would stall out, and idling was going apeshit, from 300-2,00 or more rpm. I was very confused and asked my step dad to come look at it before I drive more, then he tells me there was too much airflow from the new intake for the throttle body because when he put his hand over the intake without the filter, it calmed the idle out. I didn't see how this was possible, from just an intake, so I went home, and finished my Venturi intake project completely, deciding I'd let my friend try it on his honda. after I was done putting plastic epoxy in every little crack, I put it back in figuring what the hell...


the idle problem went away, and from 3,000+ RPM, I got a good bit more power, at a cost. from going 0-20 can take up to FIVE SECONDS


but 30+mph pulls considerably better considering just an intake mod. I don't get it at all. why


someone tell me what's going on here? do I have a bad throttle body? there is an engine light that keeps coming on for P0400 I think "bad evap system" but I'm told that has nothing to do with engine performance what so ever.

I think I might end up taking out the throttle body entirely, and clean the hell out of it, and even the upper intake manifold. when I cleaned it out the first time, there was sludge in it, which is why my car wouldn't even start.


Yeah, I have no idea why the Venturi backwords helped low end speed and made the car slightly more fast than Filter > pipe > air diffuse pipe to venturi pipe low to high pressure going towards the intake manifold



By c0reyl at 2012-04-15

this is the exact setup internally it is now, it was backwords from that. correct me if I'm wrong but like this, as it is now, it is properly installed, right?

Nice work. Like you said, your engine isn't supercharged, so the warm air isn't going to hurt much. But if you ever get a chance to change the design so that it sources air from below/outside the engine compartment, it would result in a performance gain, especially in the summer months. The PCM cuts timing when the intake air gets too warm, which makes you slower. It won't matter in cooler weather, or when you're cruising, but when you're stopped idle on a hot July afternoon, you'll probably notice a lag. Not a huge deal, just something to be aware of.

Basic but definitely check vacuum lines and stuff especially around evap stuff for leaks

Congrats for thinking out of the box. I do Airflow management and modeling professionally and can give you some insight to your project. A venturi could work and be beneficial under a narrow range of conditions. To be truly beneficial it would need to be tuned for WOT in the upper powerband and cause less restrictioniI.e. pressure drop than stock. As a practical matter it would be difficult to be effective without a dyno to tune it. There are far too many variables to factor to model this correctly unless a transient analysis (many variable modeled one by one and compared later) were done. Very time consuming. You may well get some good acoustical effects thought which can be fun.

Your MAF sensor might be dying. Please check it with a scope or TechII - or swap in a known good one.

grisolm1 wrote:

Congrats for thinking out of the box. I do Airflow management and modeling professionally and can give you some insight to your project. A venturi could work and be beneficial under a narrow range of conditions. To be truly beneficial it would need to be tuned for WOT in the upper powerband and cause less restrictioniI.e. pressure drop than stock. As a practical matter it would be difficult to be effective without a dyno to tune it. There are far too many variables to factor to model this correctly unless a transient analysis (many variable modeled one by one and compared later) were done. Very time consuming. You may well get some good acoustical effects thought which can be fun.

that would make sense as to why on 4,000-5,000 rpm, the engine seems to respond way better

what do you mean by less pressure?

and if I were to cam it, get new rocker arms and valvesprings, and re locate this to colder air input, would I be seeing better results?

Thanks for help

I think grisolm means pressure drop = restriction

Cam & rockers would improve breathing, and CAI will ensure your timing isn't retarded by the PCM when it gets hot (advanced spark timing = better torque).

I thought that the fact that the tube going from bigger tube to the smaller venturi tube would make it so that velocity an flow can increase without messing up the pressure? :o

and I'm already working on ideas for colder air

To grisolm's point, tuning a venturi type intake is near impossible without flow testing. If it were me, I'd build another one of larger diameter, sourcing air from the fender well. Do some testing and see which works better.

Yeah I know, I don't know how to use formulas or have a dyno to test :/

but I made it out of scraps, so I can't complain :3, and keep in mind, the L36 isn't supercharged, so not much can go wrong other than not enough power.


but I am noticing gains in higher RPM, it could be just me though :o

also, I kind of plan on making that scoop intake setup when I can afford a supercharger, I'm limited by funds though, and I'm kinda just playing around right now

Just did a lab assignment on Venturi tubes today, very cool to see one actually in use! Whether or not it works better than a usual pipe as a CAI, it's pretty cool to say you built a Venturi intake and it looks nice under the hood. I'm just as impressed at how clean the setup is, no rough edges anywhere!

I dont see the advantage of your venturi arrangement, especially since the pipe diameter increases once again as it goes to the throttle body, negating the velocity increase in the narrowed pipe section. Additionally the mass flow rate through the intake must remain constant and therefore the increased velocity is only occurring to make up for the lowered pipe cross sectional area, meaning that there is no additional air being fed into the engine.

L67 wrote:

I dont see the advantage of your venturi arrangement, especially since the pipe diameter increases once again as it goes to the throttle body, negating the velocity increase in the narrowed pipe section. Additionally the mass flow rate through the intake must remain constant and therefore the increased velocity is only occurring to make up for the lowered pipe cross sectional area, meaning that there is no additional air being fed into the engine.

Really? it looks like to me that in the sloped angle created by the port tube insulated INSIDE the bigger tube, it pretty much goes right up to the throttle body

I see, I was basing that off of this schematic. Regardless the intake widens to ~4" at the throttle body anyway. But after thinking this over clearer I realize I may have misunderstood your intentions with this intake and liken the effects to throttle response changes like in a single vs. dual plane carbed setup.

L67 wrote:

I see, I was basing that off of this schematic.

my bad, that was to just explain to my friend how it works pretty much :3

IBx1 wrote:

Just did a lab assignment on Venturi tubes today, very cool to see one actually in use! Whether or not it works better than a usual pipe as a CAI, it's pretty cool to say you built a Venturi intake and it looks nice under the hood. I'm just as impressed at how clean the setup is, no rough edges anywhere!

Thanks man

I Didn't think it would turn out that good either lol. At first, it was like, a proof of concept idea and a project of boredom, then I realized I could make it work, and it wouldn't actually look ghetto




Venturi Rev 2.0 is already being designed, and I have no idea if it will be a better revision or not, but it is designed to bring in colder air, and hopefully be a bit more efective

Might I reccomend putting your intake back to stock untill you discover whats giving you inconsistant throttle? Speaking from experience, its waayyyy easier to trouble shoot any issues in stock configuration and then start adding back mods when it works properly in stock form. Then you also have a better idea of how the engine responded to the mod when starting with a proper working engine.

Karma wrote:

Might I reccomend putting your intake back to stock untill you discover whats giving you inconsistant throttle? Speaking from experience, its waayyyy easier to trouble shoot any issues in stock configuration and then start adding back mods when it works properly in stock form. Then you also have a better idea of how the engine responded to the mod when starting with a proper working engine.

It was doing this on the stock intake as well. in fact, the stock intake sucked so bad that shortly after I got the car, and took apart the intake, I found a sock, acorns and leaves in the air box. I was not impressed at all.

btw, so you know, my stock intake is different than on a supercharged riv. It is complete garbage, while the L67 has a much better stock intake setup.

I will try finding a location for colder air and cleaning my throttle body more. is there any way to check if the MAF, idle, and o2 temp sensor are in perfect working order?



Also, would a bad fuel filter be doing anything like this?

Disconnect the MAF sensor and see if things improve, just dont do any heavy throttle pulls.

c0reyl wrote:

Karma wrote:

Might I reccomend putting your intake back to stock untill you discover whats giving you inconsistant throttle? Speaking from experience, its waayyyy easier to trouble shoot any issues in stock configuration and then start adding back mods when it works properly in stock form. Then you also have a better idea of how the engine responded to the mod when starting with a proper working engine.

It was doing this on the stock intake as well. in fact, the stock intake sucked so bad that shortly after I got the car, and took apart the intake, I found a sock, acorns and leaves in the air box. I was not impressed at all.

btw, so you know, my stock intake is different than on a supercharged riv. It is complete garbage, while the L67 has a much better stock intake setup.

I will try finding a location for colder air and cleaning my throttle body more. is there any way to check if the MAF, idle, and o2 temp sensor are in perfect working order?

Also, would a bad fuel filter be doing anything like this?

It doesnt matter if it still did it with the stock intake. Its just plain easier to troubleshoot these things when stock. If it did it when stock then you for sure shouldent have started adding modifications. I am aware of what the stock l36 intake is. Garbage or not, get things working in stock setup. Then improve from there. My 2c. But do what you will with it.

And "L67" is on the right track about checking out your MAF. Unplug it for a bit and see how things run. It will throw an engine light, but your MAP sensor will take over.

Edit: When you say you cleaned the TB with carb cleaner.. did you take it off? did you remove the MAF?

Karma wrote:

c0reyl wrote:

Karma wrote:

Might I reccomend putting your intake back to stock untill you discover whats giving you inconsistant throttle? Speaking from experience, its waayyyy easier to trouble shoot any issues in stock configuration and then start adding back mods when it works properly in stock form. Then you also have a better idea of how the engine responded to the mod when starting with a proper working engine.

It was doing this on the stock intake as well. in fact, the stock intake sucked so bad that shortly after I got the car, and took apart the intake, I found a sock, acorns and leaves in the air box. I was not impressed at all.

btw, so you know, my stock intake is different than on a supercharged riv. It is complete garbage, while the L67 has a much better stock intake setup.

I will try finding a location for colder air and cleaning my throttle body more. is there any way to check if the MAF, idle, and o2 temp sensor are in perfect working order?

Also, would a bad fuel filter be doing anything like this?

It doesnt matter if it still did it with the stock intake. Its just plain easier to troubleshoot these things when stock. If it did it when stock then you for sure shouldent have started adding modifications. I am aware of what the stock l36 intake is. Garbage or not, get things working in stock setup. Then improve from there. My 2c. But do what you will with it.

And "L67" is on the right track about checking out your MAF. Unplug it for a bit and see how things run. It will throw an engine light, but your MAP sensor will take over.

Edit: When you say you cleaned the TB with carb cleaner.. did you take it off? did you remove the MAF?

I didn't take off the throttle body, I just took out all the sensors and used carb cleaner. so Yes, I did remove the MAF but I didn't take out the throttle body because I don't have another gasket lying around :3