2007 Prius, mild upgrade

[don_chuwish]

Hello,

Thanks to help from many individuals on DIYMA and other forums I've just completed part of my planned upgrade. So time to share back!

There were many objectives on this, but it all started with trying to reduce road noise. That got me interested in how the stereo sounded and what I could do to improve it. Lucky for me the used Prius I got this spring was a package #2, no JBL sound system to worry about.

So I set out to keep the cargo area empty, not destroy anything, keep access to the spare tire and initially to keep the stock HU. Now I'm thinking I want to replace it, but that'll have to wait until after Christmas sometime.

The car already had speakers in all 4 doors that were upgraded from stock - Infinity Kappa 92.9i coaxial. They left the stock tweeters in the A-pillars. I decided to leave the Kappas in the rear doors for the kids to have some sounds, but put a proper set of components up front. I found Boston Acoustics SL60s were on deep discount and got them from a local shop.

For the subwoofer many Prius owners get a custom 'glass enclosure made to fit in one of the side cubby's of the rear cargo area. I didn't want to tackle 'glass myself just yet or pay for it to be done, so I looked for another option. jl doesn't make a Stealthbox for the Prius (they should!) but I found one of their ported boxes that could work: JL Audio CP108LG-W3v3

I came very close to getting an alpine PDX-5 to run everything, but price kept me in check long enough to learn that it can be noisy. I decided to get a mono for the sub and a 2 channel for the front comps, leaving the rear doors on the HU alone. Ended up with a JL J2 250.1 (new) and a JL 300/2 (used). With a stock HU I'm left using speaker level inputs, which both amps can handle. For the J2 I tapped the rear door speaker wires in the B-pillars.

So if you think about the Prius and how to power the amplifiers, it may strike you that there's a big honking battery in the car. And that is in fact a nice feature, but there's a small 12V "accessory" battery in the rear cargo area that you tap just like any car. There is no alternator. The 12V battery doesn't crank the gasoline engine so it isn't very powerful, but when the car is on there is 14.4V coming from the motor/generator and main high voltage battery pack through an inverter. If you want to sit and listen for long, it's best to keep the car "IG-On" instead of in "ACC" mode.

I've been babbling long enough, on to the pics!
Road noise abatement:
Second Skin Install
Door damping, components and subwoofer install:
Audio upgrade

There are captions with each photo that tell the story, so just click on each photo, or bounce through the slide show, however you like.

Thanks all, comments, questions, criticism and advice all welcome! I'll add more once I've done the 300/2 up front.

- D

[don_chuwish]

Since directly added pics are a lot more satisfying than a link, I'll throw some (not all) in here:

Custom MDF baffle templated from the OEM plastic one


Dead door, Xover in a safe dry spot


Making a new lid for cargo box


Grill will just clear the jl grill


I suck at carpeting


Piano hinge gives access to the box


Upgraded ground to 4ga, OEM was 10ga


4ga down to 2 8ga for front and rear amps


A perfect pair


Simple but pretty. Held in place by heavy duty Velcro


- D

[rawdawg]

That's some clean work there...

[don_chuwish]

Originally Posted by rawdawg

That's some clean work there...

Why thank you very much! The rear hatch area is easy to work with in this car and of course it helps to have the battery so close.
There's some parts I need to go back in and redo, stuff you can't see. But nothing too awful. And I still have to get the 300/2 in for the front comps, right now they're underpowered and getting full range. Poor mids try so hard to make 40Hz but just can't hack it.

- D

[ryan s]

I didn't know about the 12V battery in the trunk

So since those cars are generators on wheels, are there any people who have done bigger installs using powerful amps? Since the car converts energy from braking, can a Prius support 1,000...2,000 watts? Are the batteries that run the car also "usable" for running big draw items like big ol amps?

In other words, as long as you're driving and braking, driving and braking, you can't run out of power. But what if you're on the interstate? Can you run a stereo at full tilt at 80MPH?

[billg1230]

The 12v electrical system and the hybrid drive system are totally seperate.... You need to run your system off of the car's electrical system... not the hybrid drive battery..

[don_chuwish]

Originally Posted by ryan s

I didn't know about the 12V battery in the trunk

So since those cars are generators on wheels, are there any people who have done bigger installs using powerful amps? Since the car converts energy from braking, can a Prius support 1,000...2,000 watts? Are the batteries that run the car also "usable" for running big draw items like big ol amps?

In other words, as long as you're driving and braking, driving and braking, you can't run out of power. But what if you're on the interstate? Can you run a stereo at full tilt at 80MPH?

Well I do know of someone who's running a Diamond Audio D9 800.2 and a D6 1500.1 and did so for a long time on the OEM battery before upgrading to an Optima Yellow Top.
But you think like I do. It is a big generator on wheels, two in fact. No, you can't tap directly into the "traction" battery but you don't need to. Toyota has done that for you already. Tap the 12V battery terminals and you are indirectly feeding off of the main battery and/or the motor/generators. I can't explain it any better than Wikipedia: Hybrid Synergy Drive - Wikipedia, the free encyclopedia
But in short, it doesn't regenerate just under braking/deceleration. It'll also do it whenever it can if it doesn't need the electric motor for power to the wheels. In general it tries to keep the main battery above 60% but you can run it down farther in certain conditions. If it gets low enough, the internal combustion engine will start up JUST to recharge the battery. That happened to me as I crept along in a traffic jam last summer. I was creeping on electricity only and slowly drained the main battery down. Pretty soon the ICE started up, charged the battery for a while and then shut down again. So whether cruising the highway or parked, there's plenty of power on hand.

I can't say how much of a draw the 12V bus can handle or if a "Big 3" style upgrade would be doable. I don't plan on needing that much juice.

Here's an extreme example of what can be done tho:

YouTube - The worlds most extreme Toyota Prius

- D

[ryan s]

Aha, that's pretty sweet...as long as you have gas, you have voltage...

As for the orange Prius...umm...wow I'd scared to drive that due to all the work done to it...

[don_chuwish]

LOL, yeah I wouldn't call it practical. Mine is a bit more on the normal side. These pics were taken just after I got it this spring, used with 13K miles on it. Custom wheels, tint and PIAA fogs were put on by the previous owner:







- D

[Okuden]

Very neat integration ! Congrats.

[mSaLL150]

Props on making a prius somewhat cool, I never see any modified priuses even though my area has the highest prius population in the world. In my area, a lot of people have the prius just to make a statement and just give me these stares like I'm evil with my truck.

[don_chuwish]

Ah yes the smugmobilers. I understand both sides of that fence since I live on both sides. Our minivan isn't exactly a fuel sipper, tho it's not bad for such a large vehicle. I don't hesitate to borrow my dad's GMC pickup when needed. But when I see the MPG readout hovering near 50mpg in the Prius it's pretty cool, especially since I don't really try too hard at the hyper-miling tricks. Because mine isn't all decked out in factory options it's pretty easy to work with in terms of the stereo.

I probably won't have any significant update until Jan. But hope to get the front amp in (300/2) then.

- D

[HondAudio]

As long as you're doing an install on a Prius, maybe you could make the hybrid system all "pretty" with fancy wiring and fusing and such.

[don_chuwish]

LOL! Maybe some LED action too? Well it's already covered in bright orange loom so you know what NOT to mess with. I think I'll leave it be for now!

- D

[R1100S]

This is the cleanest install I've ever seen using a pre-fab enclosure.

You made excellent use of the space available. The rubber grommets on the right side of the amplifier in the plastic bin really do make the difference in making it look like it's SUPPOSED to be there.

This looks like the type of install I'd like to do in my father's vehicle. Simple, functional, and clean.

Do you like the sound with the factory HU and speaker-level inputs into the amps? Honestly it's getting harder and harder to integrate an aftermarket HU install into a budget install without it looking like it doesn't belong there. My dad and my father-in-law both want better sound....but are NEVER going to change the factory look of their vehicles.

Kudos. I hope it sounds as good as it looks.

[HondAudio]

Originally Posted by don_chuwish

LOL! Maybe some LED action too? Well it's already covered in bright orange loom so you know what NOT to mess with. I think I'll leave it be for now!

- D

Yeah! Put some ell-ee-deez in the headrests!

[don_chuwish]

Thanks! It's not done yet, front amp isn't in, so it's hard to judge the sound just yet. That sub has PLENTY of power for me even with that smallish amp. Remote level knob is at about 1/3.
Using the stock HU and speaker level inputs will work OK I think, but not great. I will be replacing the HU eventually. I cringe when I think about the hokey taps I used to get the rear door speaker wire signal to the amp. I want RCAs!

- D

[62Lincoln]

I looked through your installation of the sound deadener, very impressive! What are your impressions of the overall reduction in noise, given the level of detail in your install?

[don_chuwish]

Thanks for the compliment, but answering the question is tough. Deadening the doors certainly improved the performance of the door mounted mids. However in terms of road noise reduction I'm not as impressed as I'd like to be after all that work. I actually took measurements before and after with a Radio Shack sound level meter and there was no measurable difference. I'm worried that I may have messed up the measuring by using A weighting instead of C tho, so it's not perfect science. Either way, my ears weren't amazed by any dramatic improvement.
I think it comes down to the integrity of my barrier install. It was just too difficult to get a good clean gap free install with so many obstructions. Plus I couldn't get very far forward to cover the front wheel wells at all. So in the spring I'll try to tackle them from the outside. I'm really not eager to add any more weight but I want to see some results from all the work and expense.

- D

[62Lincoln]

Thank you for the thorough answer! I have experienced the same thing as you with my vehicle, a Mazda5. In my case, I could hear a little improvement after deadening the rear section, and like you, I want to figure out a way to address the front wheel wells, which seem to transmit quite a bit of road/tire noise. Please keep us updated as you work on the front wheel wells, it will be very interesting to see what kind of results you see. Your attention to detail will guarantee the best chance for improvement! Thanks again.

[yellowcard]

Very simple and stealthy. I like it a lot!

[don_chuwish]

One thing I've wondered about this setup is how it may be affecting sound vs having the box out on the floor of the cargo area. The way I've done it was based on the functional requirement more than sound and I figured it wouldn't carry enough of a sound penalty to NOT do it.
But considering it's a ported box inside an unsealed larger enclosure firing up through a hole into a hatchback it seems like an interesting environment for a sub. Anyone care to theorize what the impact will be?

- D

[iarechaga]

I have one question, since the prius is thought to run sometimes with the batteries... If you have an aftermarket amplified speaker system, does it affect the autonomy of the car?

I mean in the electric way...

[don_chuwish]

Originally Posted by iarechaga

I have one question, since the prius is thought to run sometimes with the batteries... If you have an aftermarket amplified speaker system, does it affect the autonomy of the car?

I mean in the electric way...

Hello, thanks for the interest. I get quite a few questions about how the Prius is different in terms of audio system install. But I'm not sure what you mean by "autonomy of the car".
Running a high power audio system (I'd hesitate to call mine "high power") inevitably has to impact fuel economy. It's just physics. All the electricity is generated by burning gasoline. Whatever power goes to the stereo ISN'T going to the HV traction battery for propulsion. For that matter turning on the headlights has an impact but I doubt either will be measurable.
Worse for my fuel economy has been the weight added by damping, MLV, amps and sub. Probably about one passenger worth at this point.
As mentioned in the opening post tho, you can drain down both the 12V and the main HV traction battery by sitting and playing music. When the charge on the main battery gets low enough the gas engine will start up and charge it as needed. The other day I sat listening, fairly loud, for almost an hour without bringing it down that low. Soon after restarting normal driving it was back to normal charge levels.
For more on how the whole power system works, I can't beat Wikipedia: Hybrid Synergy Drive - Wikipedia

- D

[don_chuwish]

OK, did a little more so it's time for an update: JL 300/2 bought used off of ebay installed to power the front components. I'm still struggling with a noise problem mentioned in another thread, but the physical install went pretty well.
Running wire forward from the 12V battery in the rear was pretty easy, I was able to fish it all through existing gaps along the rear strut area. I'll just comment along with the photos here:

Testing the fit, this was the original idea.


Platform keeps the amp off the heater vent


Heat sinks facing back and connections safely forward (and easy to reach). But it just barely doesn't fit.


My family thinks I'm insane. But this much dash removal is necessary to get at the HU.


First attempt at making the speaker wire to RCA connection. Soldered, heat shrinked and hissy. Switched to a LOC in the end, connected with crimp on spade disconnects. No photo tho. 12V ACC tapped in the photo but redone later as a solder splice, it was too flaky a connection.


- cont'd next post...