More hp = cracked ppf
 

Well I had my car on the lift today to check my new diff that I put in a month ago. As I was looking at everything I saw my ppf was cracked on the top and bottom right at the first diff bolt. So now im wondering if i could some how delete the ppf and make mounts that bolt to the body. Any ideal would be great for deleting the ppf.

If you're going to go through the trouble of deleting the PPF, might as well stuff something more serious in there.
Personally, I do not like the concept of removing the PPF on a street type car; it's one of the key components that gives the car strength in an accident.

damn..looks like someone is making big boy power

...or wheelhopping like a madman

Floating the drivetrain vs bolting it to the chassis makes it stronger?

I'd like to hear some thoughts behind this.

^ what he said!!!

I don't think you guys grasp the idea behind "crumple zones."

Um... PPF isnt exactly part of that system.

its essentialy a 3rd frame rail imo. I would weld reinforce of reegineer the ppf before i dumped it though. Unless you go through the same trouble as most v8 swap guys then it likely wont be as strong etc.

...yes it is. Float the drivetrain and it moves freely in the car during an accident - that PPF will twist up like a pretzel under any sort of serious accident force. Bolt the diff and (more importantly) the tranny to the car, and all of a sudden you've added a massive brace to the core of the chassis and essentially fucked the crumple zones.

Hey sav, I know the pics in this post are down, but one of our MSM'rs broke his pretty bad. What they did and you might not see it, is basically "box" it in in the rear. broken ppf MSM You know how it only attatches on one side, well, they added an extra brace on the other side of the PPF and welded it all together, gusseted everything up, it looks like a pretty legit fix. The shop which did it is listed on the 2nd page, and I'll keep digging to find more info on it. I think this would be the ticket.

Another thought is the RX-8 uses a steel PPF, and although none of the attatchment points are going to be of much use on the NA/NB, something custom might be possible and its in the right range of dimensions. What would be nice is the RX-8 PPF and RX-8 diff fit in the NC maita and all you've gotta do is cut out a section and splice it.. ok, useless to know, but interesting.

Gl with the fix, I don't think removing the ppf or drastically modifying the design is the way to go, Mazda had a pretty good reason for doing what they did, even if it can't handle the power, I'd try to make it so.

I thought the crumple zones were outside of the passenger compartment. :giggle:

last i checked all our ppfs where steel.

nope there all aluminum

definitely not steel

dumbass :bowrofl:

You bring up a good point, in my mind. We need "intelligent" crumple zones that actually crumple around the passenger compartment if the accident was caused by driver of said vehicle in accident because of some gross amount of stupidity, I.E. not signaling while changing lanes while not looking and crashing right into someone else at 90mph. ECU corrects things in the chassis, moves a few hydraulic things, and BAM, whole car crushes around driver.

Darwin wins.

on your next PPF, make sure you attach all the bolts BEFORE tightening them so you dont have a torque load on the PPF because you attached and tightened the diff bolts before you mated the PPF to the tranny.

Or hell, with 349 hp, get a good shop to tig some reinforcements on there for you

Its funny how we talk about crumple zones because any form of chassis bracing like fm butterfly brace will make it harder for a car to crumple same as if you put a cage in too.

Also the bolts where tightened after the had all been threaded in by hand.

Pinion angle?

<-- Looks forward to destroying his "crush zones" on the next build.

PFFFFT.

Is anyone realizing that the passenger compartment is what DOESN'T crumple in a crash? FM frame rails are located right under my ass, and my passengers ass. If that part of the car is supposed to crumple, we've got a big fucking problem, people.

That's my next product. Crumple zone re-appropriation kit.

Like i said any bracing will make the crumple zone be less effective.

v8 roadsters rear end kit. get the ford 8.8 and a stock 8.8 will hold litterally anything in a miata. i drove an 800hp fox body with a stock 8.8 rear with like after market gear set. never broke. when they say its good for like 500hp or w/e they rate it at thats what they are typically rated at in mustangs which weigh 3100lbs.

FWIW I stripped the frontmost receiving nuts on my PPF. That was probably because of a lot of wheelhop and doriftos.

once my car is back together im going to pull out the ppf and make custom mounts also going to order mmr diff mounts. I will post up pics once everything is done.

Yea, but you can weld aluminum, right mike? I suck balls at it, or I would make something cool like that. I think a box instead of a one-side brace would be nice, if it was practical. Actually, I'm going to go look at my transmission and see if something like that is feasible.

Assuming the 5 and 6 boxes look the same, it looks like a tough cookie to crack.. a lot of material added on just one side of the case, I dunno, if you could wrap around something to the other side, then use a sort of clamp to hold it down, you might be able to add bracing on the other side. Hard to say.
I'd still like to think of a way to increase its strength somewhat, but I dunno how, other than making a better mousetrap, I.E. just making everything bigger/thicker/stronger as it is.

I can't weld aluminum lol but steel I can do, I was also going to add bracing on to the bracing im going to make to help brace the chassis.

What kind of driving are you doing that broke this thing?
What diff mounts were you running when it broke?
I beat the piss out of mine and its never broke.
This is amazing to me.

Whats this crumple zone shit anyway? thought this was about HP breaking a PPF??

Drag racing mostly and daily driving. Mazda comp diff & engine mounts. The crumple zone stuff came up because I guess the ppf is a main crumple zone but like I had started to say once you add any form of bracing to the chassis you start to eliminate the crumple zones.

It isn't much trouble at all. For the OP I'd call Martin at monstermiata.com and get his back half kit including rear hangar, broached hubs, and half-shafts. It is easy enough to fab a tranny crossmember, and a new driveshaft would have to be made. You'd be looking at some coin, but it's not that difficult.

Disagree there with the FM butterfly brace, they added something similar from the factory on 03+ cars at least. Doubt they re-engineered the the crumple zones for that.

I know that in 03+ they did a brace like FM but I think the mazda factory one crushes easier then FM due to add frame rails.

Haven't we already concluded that the area between the fuel tank and the firewall is the passenger compartment which is not designed to crush? It is designed to protect its occupants which means staying intact. Are you guys seriously debating this?

trust me man they fail epicly on some things and we go off on some horid tangents.

You Guys for the WIN:beer:

I understand how the PPF can be a crumple zone without the passenger compartment being a crumple zone. If you hit a barrier head on, the engine is going to need to allow the car to crumple forward around it. Without crumple, the engine will hit something and immediately shear the differential off the mounts.

But how does the driveshaft play into this 'crumple zone'???

Why does it have to shear the diff bolts? The front and rear structures are intended to yield to impact forces. With a direct hit to the front of a miata I would expect significant compression to the front of the vehicle. If any force is transmitted through the transmission then one would have to assume that the drive shaft and at least one u-joint is toast. The PPF would further transmit the load to the rear diff and in turn the rear subframe/hanger. I would expect yielding in possibly all of these components including the rear unibody section of the miata. All of those bolts are large, and I would not expect to see them shear. You are going to have one helluva sore driver, too.

I think we should just start digging up videos of miatas crashing along with the DOT test video if there are any. Then we should look into why we think of safety when we buy a car that is smaller then most cars on the road. Truly think about it these car are far from safe and came with 140chp for the soul reason so that we could not get into high speed MVAs.



LOL

I would suggest that large does not mean safe. Again, be careful making assumptions. I've known many to get into wrecks in miatas (many of them with totalled cars) and none of them have been hurt significantly. Check HardDog's website for the wreck photos. These cars are pretty amazing.

Oh I know that last post of mine was mostly BS kinda for haha's but yes they are amazing. I went sideways into a poll at 45mph and I opened the top and walked away then later fixed and sold the car. I have looked at the pics on there site, i think im also going to end up getting a full cage put it to work with the soft top the car from this point is no longer going to me my DD.

I wish that you were closer. I have a DOM main hoop already bent that I'd get rid of.

willing to ship???

oof.....it's pretty big.

post up a pic.

uh, okay......it's a roll bar hoop like the one below :fawk:

http://www.fordmuscle.com/TEX/Rollbar/8.jpg

hmmm

Anyone ever seen an SUV get hit by a smaller Sedan or the likes? We had a chick at MS.com hit a guy in his HHR while back, she was in an SUV. The front of the car was toast, but it was cool. But, the mountainer rolled a few times in a 30-40mph accident.

When SUV's and similar high-roll center cars get hit low, especially from the sides, its a round and around you go. They don't really flip, but man can those bastards roll for a while. Had a bud who also rolled his Ford Exploder 3 times for no damn reason (one accident) and it just astonishes me.

4200-5200lbs or better for most of those vehicles, and in most cases, way less safe. Don't forget "safe" also means the ability to avoid the damn accident in the first place. Better visibility and manuverability in a Miata than a lot of the common crap out there.

Very true.