Infinity Design E9x M3 air intake system

This air intake system has been on my radar for a while and I decided to order one a couple of weeks ago. I finally installed it and I’m very happy with the results. I have to say that this system is worth the price of admission. Everything is top notch, whether it’s fit, finish, overall quality, looks or sound.

The system comes very well packaged in a single box. The complete airbox and elbow(with air filter) are wrapped in foam and are then put into their own separate string bags with the name and logo of the company on it, a nice premium touch.

There is a separate plastic bag containing the silicone coupler and clamps for connection to the plenum and the rubber coupler that goes between the front air duct and the airbox. You also get a nice looking certificate of authenticity to prove this is the real deal.

When it comes to installation, it’s nothing complicated, but some steps have to be done in the right order. After removing your old intake system, you can start by installing the bottom of the airbox first. You then have to reinstall the stock front air duct with the provided rubber coupler attached to it and slide the coupler on the airbox inlet.

After the front duct is back in place, you can now install the elbow with the air filter already attached to it. Just make sure the air filter is well seated in the elbow and the clamp is well positioned so the seal is good. I tried installing the silicone coupler on the plenum first, but I had a hard time sliding the elbow in after. Putting the coupler on the elbow first was the better way to do it for me and I was then able to slide the coupler over the plenum inlet.

Infinity provides a warning to not overtighten the clamps as carbon fiber can crack. Only use hand tools to do this job and don't force anything. Just make sure it’s tight and all will be good.

The last step is to fit the airbox lid. You have to slip it inside the rubber coupler that connects to the front air duct and that can be a bit tricky. I used a plastic trim removal tool to stretch and align the coupler so the lid would slide inside. A bit of patience is all you need. The screws that secure the lid to the airbox are pretty small, so having a magnetic hex key to install them would help. I didn’t have that on hand, so I stuffed all the voids around the airbox with microfiber towels to prevent the small screws from falling in the engine bay. I suggest you do the same even if you have a magnetic tool, it might save you a headache.

When you’re done you notice everything fits perfectly and looks as if it could have come from BMW if they had made a full carbon intake. The fit and finish are amazing, this system is a work of art, truly impressive. It looks incredible in the engine bay.

The sounds of it are intoxicating as well. My car already had an Eventuri plenum with a Dinan intake, so it already sounded great, but this takes it up another notch. If coming from a fully stock intake, the difference would be even more noticeable.The carbon fiber airbox, the mammoth elbow and huge 170 mm air filter just intensify the intake sounds even more. Punch it around 3500-4000 rpm and the sound is spine tingling, you can’t get enough of it. There’s a more agressive bark on downshifts that is addictive as well. The throttle response and power delivery feel great, even better and more urgent than before. Maybe the increased noise helps to make it feel that way too. In any case, I think there was an improvement in those two areas and it just feels awesome. I will say that the pairing of the Eventuri plenum with this intake system is heavenly and the absolute best full intake system for this car in my opinion. The finish on both matches perfectly, which is a bonus.

Overall, this is a 10/10. It’s not cheap, but if you have the money and want the best, this is it.

Great review! Had strongly considered this before settling for my Dinan Intake.

Could you elaborate on the difference in sound with this vs the Dinan? I will be installing an Eventuri Plenum as well so this would be my exact setup.

Also did you buy from them directly? Were they offering any promotional pricing?

a5m wrote

Great review! Had strongly considered this before settling for my Dinan Intake.

Could you elaborate on the difference in sound with this vs the Dinan? I will be installing an Eventuri Plenum as well so this would be my exact setup.

Also did you buy from them directly? Were they offering any promotional pricing?

I would say that, at low rpm, they sound similar, but the Infinity has a bit deeper sound and more resonance when you get on the throttle thanks to the full carbon airbox, mammoth elbow and huge 170mm air filter. When you're cruising in 3rd gear around 3500-4000 rpm and you floor it, there's a manic and intense sound that was not there with the Dinan, again courtesy of all the huge carbon goodness! Nothing against the Dinan, it's a great quality intake and I enjoyed mine, but the Infinity is just a notch above in my opinion. It also didn't match my matte Eventuri plenum, while the Infinity matches it perfectly. I just prefer matte to gloss.

If you have the means to buy the Eventuri plenum and this intake, go for it. The pairing is incredible and the quality of it all is unmatched. It's not cheap, but it's worth it.

I bought it directly from the Infinity Design website and it took two weeks for me to get it. There was no promotion going on at the time I purchased it.

Very nice. At one point I thought I read that Infinity was going to offer a plenum as well… have to look and find that.

RG m3 wrote

I would say that, at low rpm, they sound similar, but the Infinity has a bit deeper sound and more resonance when you get on the throttle thanks to the full carbon airbox. When you're cruising in 3rd gear around 3500-4000 rpm and you floor it, there's a manic and intense sound that was not there with the Dinan, again courtesy of the carbon airbox. Nothing against the Dinan, it's a great quality intake and I enjoyed mine, but the Infinity is just a notch above in my opinion. It also didn't match my matte Eventuri plenum, while the Infinity matches it perfectly. I just prefer matte to gloss.

If you have the means to buy the Eventuri plenum and this intake, go for it. The pairing is incredible and the quality of it all is unmatched. It's not cheap, but it's worth it.

I bought it directly from the Infinity Design website and it took two weeks for me to get it. There was no promotion going on at the time I purchased it.

Thanks so much. This sounds like a worthwhile upgrade over the Dinan. There isn't much at all out there on this intake from Infinity or anyone else, so this is immensely helpful.

Understand about the finish. Dinan only offers the one. They will also work on the price (or at least they did last year when I inquired) but for what you're getting which is a full carbon airbox plus intake $1500 isn't that bad.

I'm waiting on their plenum too. Would be an epic pairing if their track record with the M5 is anything to go off of.

a5m wrote

Thanks so much. This sounds like a worthwhile upgrade over the Dinan. There isn't much at all out there on this intake from Infinity or anyone else, so this is immensely helpful.

Understand about the finish. Dinan only offers the one. They will also work on the price (or at least they did last year when I inquired) but for what you're getting which is a full carbon airbox plus intake $1500 isn't that bad.

I'm waiting on their plenum too. Would be an epic pairing if their track record with the M5 is anything to go off of.

Yeah, I heard about Infinity working on a plenum, curious to see if it will happen or not. I think this intake is priced right. I could have went with the Eventuri since I have their plenum(the updated version) but it would have cost me the same or even more for an elbow, air filter and airbox lid.

With this you get the full carbon airbox for around the same price, so it's a no brainer, it's the better value and the better system in my opinion.

Hmm...I like it. Will this work with a Harrop Supercharger?

rotomoto712 wrote

Hmm...I like it. Will this work with a Harrop Supercharger?

No, this is for naturally aspirated cars. If you look at pictures of the Harrop, you'll see that you have to keep the stock airbox because the elbow they provide is made to fit the stock airbox.
The Infinity airbox has a bigger opening to make room for the huge elbow and air filter that come with it.

Because the Harrop plenum has a different inlet shape, size and angle compared to stock and aftermarket plenums, it is unique, you can't match it with any aftermarket intake. Those will only fit naturally aspirated cars.

a5m wrote

Thanks so much. This sounds like a worthwhile upgrade over the Dinan. There isn't much at all out there on this intake from Infinity or anyone else, so this is immensely helpful.

Understand about the finish. Dinan only offers the one. They will also work on the price (or at least they did last year when I inquired) but for what you're getting which is a full carbon airbox plus intake $1500 isn't that bad.

I'm waiting on their plenum too. Would be an epic pairing if their track record with the M5 is anything to go off of.

I sent the link to this thread to Salman at Infinity Design and he saw the interest for the plenum. He gave me some information regarding it. He told me I could share on the forum. Here's what he said:

"I noticed people are asking about a plenum. It's almost finished on our side and it is a beast of a thing. Interchangeable velocity stacks. Larger curved stacks than stock to start with. Then people can also have short straight stacks too for more top end power.
Like our S85 plenum we have made the throttle body adapters and velocity stacks bolt into each other so that there is zero risk of failure like the majority of plenums out there of which many have failed and the entire piece becomes scrap.

We are just debating about the lid design at the moment. Otherwise it's finished."

Sounds like more Infinity Design goodness is coming our way, but we don't know when exactly.

RG m3 wrote

I sent the link to this thread to Salman at Infinity Design and he saw the interest for the plenum. He gave me some information regarding it. He told me I could share on the forum. Here's what he said:

"I noticed people are asking about a plenum. It's almost finished on our side and it is a beast of a thing. Interchangeable velocity stacks. Larger curved stacks than stock to start with. Then people can also have short straight stacks too for more top end power.
Like our S85 plenum we have made the throttle body adapters and velocity stacks bolt into each other so that there is zero risk of failure like the majority of plenums out there of which many have failed and the entire piece becomes scrap.

We are just debating about the lid design at the moment. Otherwise it's finished."

Sounds like more Infinity Design goodness is coming our way, but we don't know when exactly.

Oh man! Maybe time to unload my Eventuri now

The interchangeable velocity stacks is interesting. I'm guessing they'll provide optimal configurations for intended purposes, but seems like they're saying there will actually be performance gains, which isn't the case with the Eventuri.

a5m wrote

Oh man! Maybe time to unload my Eventuri now

The interchangeable velocity stacks is interesting. I'm guessing they'll provide optimal configurations for intended purposes, but seems like they're saying there will actually be performance gains, which isn't the case with the Eventuri.

I think you're right, this plenum could offer performance gains that the Eventuri doesn't. Based on this information, this should have a removable top for access just like their S85 plenum.

It will be interesting to see what it will look like once they finalize the lid design. I really like my updated Eventuri plenum and the stockish look of it, but I'm curious to see this one.

I'm really happy with the setup I have now, but, like I told Salman, if I ever have issues with the Eventuri plenum, you'll hear from me!

I went for a drive tonight and decided to make a couple of videos of the intake sounds of this pairing. My girlfriend was holding my phone and we had the sun in our faces for most of the drive, so forgive me for the image quality. The microphone did pick up the sounds better than expected though. It might not be 100%, but it's not that far off.

If you are wondering what this pairing sounds like, this will give you a good idea.

RG m3 wrote

It's impossible to tell if there are nuts and possibly a washer underneath the epoxy to solidify everything. Those bolts can't just be going through the bottom of the velocity stacks and be held by the epoxy, that wouldn't help much at all. Like you said, there are no visible metal collars inside. Maybe Eventuri could chime in to explain the design.

Sorry I deleted my post because I replied in the wrong thread, the other one is here:

Eventuri Carbon fiber Plenum – Broken inlet trumpet

But you're right, can't just be screwed into epoxy. I think the epoxy is acting like thread locker. Would be interesting to see what Eventuri says.

RG m3 wrote

I went for a drive tonight and decided to make a couple of videos of the intake sounds of this pairing. My girlfriend was holding my phone and we had the sun in our faces for most of the drive, so forgive me for the image quality. The microphone did pick up the sounds better than expected though. It might not be 100%, but it's not that far off.

If you are wondering what this pairing sounds like, this will give you a good idea.

The video isn't showing! Video! Video! Video!

a5m wrote

The video isn't showing! Video! Video! Video!

Sorry, I'm uploading the videos in the attachement manager and it works, but then it doesn't show in my post when I submit.

If you want, you can pm me your email and I can send you the videos.

I put the videos on YouTube since I was not able to add them here for whatever reason. Here they are:

RG m3 wrote

I put the videos on YouTube since I was not able to add them here for whatever reason. Here are the links:

I haven't even watched the other two and I'm ordering this intake and putting on my plenum yesterday. Wow that sounds epic! Thank you!

I have to ask, you probably didn't notice much of a power difference? Salman said that some cars see gains while others don't, so wasn't sure what to make of that. But he did say based on their dyno testing that hp and torque are increased throughout the rev range. So peak gains may not be much but power will be increased within the RPM range.

P.S. Great job with the videos btw, great sound quality, and the dictating makes it so much easier to watch and observe the sound

a5m wrote

I haven't even watched the other two and I'm ordering this intake and putting on my plenum yesterday. Wow that sounds epic! Thank you!

I have to ask, you probably didn't notice much of a power difference? Salman said that some cars see gains while others don't, so wasn't sure what to make of that. But he did say based on their dyno testing that hp and torque are increased throughout the rev range. So peak gains may not be much but power will be increased within the RPM range.

P.S. Great job with the videos btw, great sound quality, and the dictating makes it so much easier to watch and observe the sound

My pleasure, thanks for the compliment! These are the first videos I ever posted on Youtube. All the credit goes to my girlfriend really, she was the one recording and holding the phone as steady as she could on top of the dash while I was enjoying the drive! The first shoot was a flop because when I floored it, she was thrown back so hard in her seat that she dropped the phone to the floor! We had a good time doing this, she's awesome. The sound did come out better than I expected, so I was happy with the results.

When it comes to power, the increase is mostly above 6000 rpm when the engine needs more air and the huge elbow and air filter provide it. Infinity says so and their dyno chart backs it up. It's not something you can realistically detect by driving, but it feels so good and pulls hard up top.

Maybe you feel a bit more power, it's hard to say, but you feel improved and instant throttle response and of course the sound makes it feel more powerful in a way. Honestly, I don't care if this makes more power than before because it feels great and sounds awesome, which is what I'm after.

This car is all about feel and emotion and boy does this pairing push this car way up there in the stratosphere! This creates a driving experience that's extremely hard to beat, no matter the price.

I don't care what anybody says about the S65, it's one of the all-time great engines. Period.

I talked to Salman at Infinity Design today and he gave me some new technical information about their upcoming plenum that I want to share.

Here's what he said:

"Also, the plenum will not open from the top. To change the velocity stacks the whole plenum needs to be removed and the stacks will go in from the bottom. Otherwise there's too many screws at the top to hold the lid down and this requires them to be checked every few months."

So the design will be different than the S85 plenum, which is a different beast with its angled throttle bodies.

The only thing left for them to do at this point is to finalize the lid design. It will be interesting to see what they come up with.

RG m3 wrote

My pleasure, thanks for the compliment! These are the first videos I ever posted on Youtube. All the credit goes to my girlfriend really, she was the one recording and holding the phone as steady as she could on top of the dash while I was enjoying the drive! The first shoot was a flop because when I floored it, she was thrown back so hard in her seat that she dropped the phone to the floor! We had a good time doing this, she's awesome. The sound did come out better than I expected, so I was happy with the results.

When it comes to power, the increase is mostly above 6000 rpm when the engine needs more air and the huge elbow and air filter provide it. Infinity says so and their dyno chart backs it up. It's not something you can realistically detect by driving, but it feels so good and pulls hard up top.

Maybe you feel a bit more power, it's hard to say, but you feel improved and instant throttle response and of course the sound makes it feel more powerful in a way. Honestly, I don't care if this makes more power than before because it feels great and sounds awesome, which is what I'm after.

This car is all about feel and emotion and boy does this pairing push this car way up there in the stratosphere! This creates a driving experience that's extremely hard to beat, no matter the price.

I don't care what anybody says about the S65, it's one of the all-time great engines. Period.

Thanks again for the thorough response. Glad you guys had fun making the video lol. Looked like the car pulled really hard on the on ramp. Agreed, I think the S65 is the best sounding V8 ever created.

I figured the difference wouldn't be substantial enough where you can easily detect it, but like you said, it's more for the sound and it completely delivers on that front.

RG m3 wrote

I talked to Salman at Infinity Design today and he gave me some new technical information about their upcoming plenum that I want to share.

Here's what he said:

"Also, the plenum will not open from the top. To change the velocity stacks the whole plenum needs to be removed and the stacks will go in from the bottom. Otherwise there's too many screws at the top to hold the lid down and this requires them to be checked every few months."

So the design will be different than the S85 plenum, which is a different beast with its angled throttle bodies.

The only thing left for them to do at this point is to finalize the lid design. It will be interesting to see what they come up with.

Very interesting. I also thought it'd open from the top. I personally like the OEM+ look, so if they can keep it as close to that as possible I'd be happy. Maybe they can offer variants?

a5m wrote

Thanks again for the thorough response. Glad you guys had fun making the video lol. Looked like the car pulled really hard on the on ramp. Agreed, I think the S65 is the best sounding V8 ever created.

I figured the difference wouldn't be substantial enough where you can easily detect it, but like you said, it's more for the sound and it completely delivers on that front.

Very interesting. I also thought it'd open from the top. I personally like the OEM+ look, so if they can keep it as close to that as possible I'd be happy. Maybe they can offer variants?

My pleasure, glad to help. We did have fun!

Agree with you on the OEM+ look, it's also my preference. We'll see if they offer choices or not.

I also agree with you on the S65, it is the best sounding V8 ever, such a wide range of sounds, from low down rumble to high pitch scream up top, such a musical instrument. I think this is what you hear when you get to heaven!

RG m3 wrote

I sent the link to this thread to Salman at Infinity Design and he saw the interest for the plenum. He gave me some information regarding it. He told me I could share on the forum. Here's what he said:

"I noticed people are asking about a plenum. It's almost finished on our side and it is a beast of a thing. Interchangeable velocity stacks. Larger curved stacks than stock to start with. Then people can also have short straight stacks too for more top end power.
Like our S85 plenum we have made the throttle body adapters and velocity stacks bolt into each other so that there is zero risk of failure like the majority of plenums out there of which many have failed and the entire piece becomes scrap.

We are just debating about the lid design at the moment. Otherwise it's finished."

Sounds like more Infinity Design goodness is coming our way, but we don't know when exactly.

Wow. That’s one way to scare potential buyers away from buying other brands of CF plenums. If making claims that the majority of other brands of CF plenums on the market have had velocity stack failures is posted to the forum then supporting images and/or references to failures needs to be included. Also, if velocity stack failures are so widespread then where are all of the threads on the forum supporting his claims? This is the first time I’ve heard of this. There have been other types of failures but velocity stacks? No two CF plenums use the same velocity stack mounting scheme yet all have failed