Akebonos vs Upgraded BBK
 

After rebuilding the sport Akebonos this past weekend, my friend and I were pretty impressed with their size, heft, and finish. Aside from 4 vs 6 pistons, in what respects do the Brembo and AP Racing BBKs 'out-do' the Akebonos? I'm curious where the improvements truly reside.

extra piston

Better heat management as well. You probably wouldn't want to run the Akebono setup in a wheel-to-wheel competitive environment.

Larger mass and larger pads make the heat hold off longer. I think the brembos would probably cook after more than 30 minutes though. Fortunately, the fuel issue limits the time on track to 30 minutes max.

The calipers are a great solid design and would be more than adequate on a similar size and weight car with proper cooling. They are more substantial than the brembos on camaros, and they don't have problems

My AP-Racing BBK really has helped me allot since going turbo! But I come from a non-sport model so I did not have the Akebonos so I cannot speak for them.

Figured it was more a paucity of cooling rather than a caliper fault after seeing how well made the calipers look when disassembled.

I am cooking pretty much every pad I put in even the AP caliper. Without improving the cooling it seems pointless to upgrade the caliper. I would attack the cooling solutions first and see how the stock brakes hold up after that.

What do you guys think of some ducting from the fangs that attaches to and stops at the wheel well liner (hole cut in liner, tubing doesn't go through it). It would funnel a butt load of fresh air into the entire wheel well, but it wouldn't be delivered directly on the rotor. It would avoid any rubbing issues with ducting inside the well. Also, some huge ducting could be used since there would be minimal clearance issues. It seems our wheel wells are totally stagnant, and perhaps it would be enough to make a considerable difference. Thoughts?

Possbly, but I think ducted to the rotors would be best. Worth a try though. The corvette factory ducts just vent into the opening, but they taper down from 4" to 1" for velocity

I definitely think directing the ducts onto the brakes themselves would be most effective. Not quite sure how well just introducing more air into the wheel well would help.

I don't think it would be too terribly hard to rig a ducting system that blows air directly onto the brakes. Doing a quick google search comes up with a lot of nice custom-fabbed setups that look fairly easy to make. The most time consuming part would just be fabbing flange mounts and making sure you've got proper clearance.

Into the wheel well isn't going to be enough, has to be close to the brake rotor as my big *** wheels seem to block any passive air flow.

Travis had a custom kit made. Stillen is supposedly working on one (they have it on their press car) but any emails to them have fell silent.

I recall looking at Travis' log but he never extrapolated on the design. I'm not holding my breath for the Stillen kit as 1) they'll make everyone buy their fascia and 2) it will require plenty of labor, cutting, and redesigning to make it fit most likely (given how their other parts usually go).

The main problem I noticed when looking at the car with the fascia off is there are three options for getting air to the rotors if piping from the fangs. You can cut through the wheel liner and hope you don't have clearance issues with ducting in the wheel well. You can cut a hole in the bulkhead to pass the ducting through but you'll never get a 3" tube through there without some serious cutting. Finally you can route the ducting under the bulkhead and then back up, but you'll have ground clearance problems and have to cut or remove the underbody cover.

I'm leaning to a NACA duct pickup right by each wheel much like Modshack posted a while back on his Audi. My goal would be a single unit that bolts on with one or two bolts and can be easily removed when not desired.

I looked at it closely when I installed the oil cooler and as I remember there were quite a few openings but unfortunately they were all on the small side and would need to be enlarged. Probably the easiest route is through the fender liner, there should be enough clearance from the wheel if you route it carefully. You could even reduce the duct size at that point if necessary.

The main thing that I'm looking for is a metal duct outlet for the wheel hub. I don't have any equipment for welding so making this part is more or less impossible for me. The rest of it I'm sure I could hobble together from off the shelf parts.

Keep in mind that all parts supplied to OE manufacturers are made to a strict budget. We can surmise that one of the reasons that Nissan went from Brembo to Akebono was cost. To make calipers and rotors at lower costs, several features that improve performance/stiffness/feel/response/etc. get cut back as they are too expensive.

Also consider that the OE's usually require a cost-down schedule. This means they typically agree to pay 'X' during year one, 'X - 2%' in year two, 'X - 4%' in year three, and so on. Those cost reductions must be found by the supplier if they are to continue making money on the program. If you have ever owned a late-run GM vehicle, you might have suffered from this "cheapening" phenomenon. Those cars are usually better in year two or three, when all the bugs are worked out. But years 4, 5 and 6 get riddled with "cost-down" parts, which we has been proven to hurt reliability. I'm not saying the Akebono bits are going to get worse over time, but there is a tremendous amount of pressure on part manufacturers to reduce costs over a several year supply contract.

AP Racing aftermarket calipers, while not nearly as expensive as the full-race hardware, incorporate several features that OE calipers typically do without. That is, if you are not talking about the AP calipers that are OE on Bugattis, Koenigsegg, Lotus, Pagani, Gumpert, Ascari and the like.

One example is caliper optimization. AP invests an ENORMOUS amount of engineering R&D time and testing into making sure that each caliper model is a stiff and responsive as it can be. For example, three changes were recently made to the CP7040 6-piston calipers (the ones in the Z & G front kits) that are hardly noticeable without pretty sophisticated measuring equipment. Why would they go to all this expense for such small changes? It turns out that some of the lessons learned from the latest Radi-Cal development (NASCAR, Formula 1, others) were directly applicable to this particular caliper. Without question, they were incorporated, tooling modified, CNC programs changed, new hardware sourced, etc. A 12% improvement in dynamic stiffness (in all 3 planes) was observed as a result.

And that's just one aspect of the caliper. There are also plenty to talk about when it comes to properly vented, 2-piece rotors that are made from much better iron than the typical OE stuff.

You just won't see that sort of attention to detail on typical (less than US$80k) OE vehicles as the budget is just not there to support it. Sure, the level of fit and finish required is high, but don't expect optimum performance. If any additional R&D is spent on the OE units, it will only be due to a quality problem such as premature leaking, noise, etc. OE budgets usually do not provide for continuing development. Lessons learned from one run get wrapped up into development of the next project.

Awesome response Chris. This is the kind of stuff that makes me want to buy AP's. I talked to stillen already and I may be doing it over the holiday season, who knows, hopefully they get that holiday cheer in them.

Thanks again for taking time to post on this forum.

I too appreciate the thorough response. It's interesting to hear about some of the nuances behind the expensive 'big-boy brake' kits (BBBKs).

While I'd love a set of AP Racing calipers, realistically caliper selection doesn't sound like my limiting factor at the moment. Moreover, it sounds like any caliper will get fried with the current state (or lack thereof) of brake cooling on the Z. Once I address that problem, I can potentially stand to benefit from the advantages Chris described.

i can't explain much about brakes but i can tell you that the AP Racing BBK comparing the Akebono's are night and day differences. These AP stop's like crazy!

Good info. i didnt know that.

Agree on the quality of Chris' posts!... you too, weiboy!

Here's the link to my brake cooling setup mentioned previously http://www.the370z.com/members-370z-...tml#post705230

... it seems to be working... I'll measure temps weekend after next and we'll compare to where they were pre-cooling... but I know it is working, as I'm no longer seeing smoke come off the brakes when I finish a session! lol... and no fade, no ice mode...

I was originally concerned that the tires would rub the tubing but that has been minimal and not caused any problems

And yes, they do mount directly to the OE fang locations and draw air from those points... pictures should clarify the setup, but any questions go ahead and ask here or on my journal

Hey Travis, glad the ducts are working. I posted on your journal as well, but it looks like you've removed all the wheel liners, trays, etc for your weight savings. Is that the case or were they just taken off for the photos? Certainly that makes routing the hoses much easier and isn't practical for anyone who daily drives. Do you think a similar route can be taken with all the OEM pieces in place? I know another member did some chopping of his liners, but he crushed the ducts nearly 50% of their diameter to clear the wheels when turned. This has to really hinder the flow he's getting.

great post Chris from AP racing, but cant a manufacture find the savings (the -2% a year) in other facets of the process of producing the calipers? ie. modifying the indutrial engineering side to help make them more efficently?

i like my factory brakes, but i would LOVE a set of AP brakes.

keep up the good work Chris.

...or provide a high quality caliper at a savings to the consumer because a manufacturer like Nissan is buying them in massive quantities?

It's cheaper to use lower-cost materials than it is to invest the time and money into developing more efficient manufacturing processes.

To Spearfishes point, we are definitely benefiting from volume discounts. It's just very expensive to put racing-quality calipers on a (relatively) cheap production car like the Z.

From the OE programs I've been involved with over the years, the parts supplier often quotes a little lower than they really want to be. Once the production items are all sorted out, the project usually gets handed off to "cost-down engineers". These guys/gals to nothing put pick over the bones looking for every reduction possible (materials, processing, part count reduction, efficiency in assembly and so on). Their priority is cost, not performance improvements. They must find cost reductions or their employer cannot justify having them there.

Damn them!

There are many huge benefits of going to a quality bkk. You have the advantages of better forging, monoblock(if you decide to go that route), higher rigidity, thicker rotors, and bigger pads. All of these add up and make the braking a lot more consistent, powerful and reliable.

Sounds good. I'd love to upgrade but the price would lead to divorce for me. I'd still venture that a Z with Akebonos and brake ducting will stop better and more consistently than a Z with no ducting and a BBK. Ducting AND a BBK....pure braking bliss.

I hate my monoblock brembos. Its a major pain in the butt to change brake pads. Have to remove the caliper to do so. However, for the front upgrade using stock rotors, the price can't be beat.

I attest to the braking bliss! :hello:

Will say that I drove a ZR1 at chuckwalla raceway the other day and the braking was from the gods!... I can only imagine what a set of those carbon rotors costs! ouch

carbon rotors :yum:

Carbon.. gets into a whole new world of cool.. wish we could do these for the 370Z.. but the cost might just be a bit out of reach for most..


http://www.stillen.com/brakecatalog/...mic_matrix.jpg

drools...

I see how it is! Steve makes all the coolest stuff for his ride! Guess I'd do the same... good on ya, mate!

Hi Guys,

Don't have many posts on the board as I'm more of a lurker than an avid poster. I have been doing many track days here in Canada, and ran into problems with my brakes on my last track day they overheated and i got quite a scare as i lost almost all my braking power. Its not cold over here so no more tracking and my main goal is to keep the car on the road in the snow ( exciting enough even with winter tires)

Been doing research on upgrading brakes, I messed up the rotors on my last even so will need to upgrade those, along with new pads and figured if im at it throw in some SS lines. looked at the pricing and saw it would be expensive since most items are expensive to ship from the US to canada.

SO got me thinking, go big or go home, looked at BBK;s and like the reviews of the AP kit. I stumbled across this thread and with stillens extra discount i might pull the trigger, but with concerns of lack of airflow, I dont want to spend the big cash for better brakes that will still overheat due to bad airflow. So basically asking people with AP's and more tracking experience if my best bet would be to get the stillen j hook rotors and xp 12,20 pads along with SS lines or go big get the bbk and never have to worry about failing brakes.

I know this is very long and there is no conclusive answer as it is all subjective, but i would really value people's opinions.

thanks in advance,
md-370z

there are folks here that seem to be doing reasonably well with the akebono brakes for track use, so I think you can survive with these if you find a way to get air to them... but if it were me, I'd always have lingering doubts about whether they were going to hold up and with braking that's just not acceptable in my book

my opinion is if you plan to continue tracking the car regularly - get the bbk... I did more than a dozen sessions on AP Racing bbk in Arizona heat with almost no fade and no 'ice mode'... since then, I had a custom air cooling setup installed that was ~10 hours labor and about $200 in parts... I'm sure you checked it out in the link above... it seems to work

If budget becomes an issue - suggest you invest in front kit + front cooling, and do the back later... Once done, you will not have to worry about out of the ordinary brake failures... plan on getting $600-900 for your old brakes - should be able to sell them on ebay

I'm using ferodo ds300 pads btw

I've tracked with the stock brakes and the AP's. The worst part about the stock brakes was that they gave you little feedback that they were about to go away, the stock pads in particular were very easy to overheat so you don't want to use those on track. With a better pad like the XP12 you will get a lot better heat tolerance and you should be able to complete your sessions without problems, but the dust seals on the Akebono's are going to be toast.

With the AP kit I have been able to torture the brakes, but a high temp pad is a must if you really press them hard. I still come into the pits with smoke coming off the brakes more often than not, so brake cooling is going to be my next priority.

I say if you really do a lot of track than it is a worthwhile investment.

wow thanks for the speedy reply, will i not run into brake bias issues if I only upgrade the front? I know most of the braking power comes from the front just want to be sure that if i were to only upgrade the front the dynamics will not change for the worse. I saw your ducting and it looks great, but Not sure if I would run with so many panels removed as my dd, So in your opinion travis your AP BBK held up well in the arizona heat without increased ducting. ( Am i safe to assume you tracked first without extra ducting or did you go straight into duct mods?)

thanks again.

if you have an issue with too much front bite, you could switch to a more aggressive rear pad... realize this is not the most elegant solution but would hold you over for a while... again, only do this if you don't have the budget to do the rear at once with front

what I was saying is that, yes, did a dozen plus sessions with no ducting, then recently I added ducting and it has only gotten better... as I mentioned above, with the air cooling I do not see any smoke coming off the brakes after sessions... will take some temp readings next weekend and report back, but I'm confident temps are 50-100f or so lower now


also, if you haven't already read these
http://www.the370z.com/brakes-suspen...ap-racing.html
http://www.the370z.com/brakes-suspen...track-use.html
http://www.the370z.com/brakes-suspen...installed.html

Chris, have you talked to our brake manager (AP-Chris on the boards here) about some track-dedicated pad options? I'm under the impression if you're pushing them that hard, we have some almost-NASCAR type pads that should take everything you can throw at them. If you're not melting seals and the like, you might just need a heartier pad.

And am I missing some in-car video of your track sessions or what?? You must be wringing the crap out of your Z! LOL!

My Akebonos performed very well at Road America with Carbotech XP10/8 pads and RBF600 fluid. Really no problems pulling the Z down from 125mph to about 30mph in turn 5 after the middle straight. The dust boots were toast, but that's why I did the brake rebuild and posted the DIY. Worst comes to worst, I'll rebuild the brakes at the end of every season. And the project this winter will be some custom brake cooling...we'll be glassing our own scoops for our kit if there are issues running sufficient ducting from the fangs.