Big brake kit

[Nessy]

Hi All.

As we have very particular laws regarding engine swaps in Sweden, i need to fit bigger brakes on my roadster for it to pass MOT. Rules state the car has to have changed brakes system, engine, gearbox, and final drive (LSD in my case) in order to be able to register with the swapped engine. In my case I will have to e85 convert the engine aswell and run it on standalone management and provide Dyno papers for the swap to be eligible. In short, the process is a nightmare compared to the us/UK legislations.... The bright side is, I guess, I will have a quite stout MR2 in the end.

Om fitting a 1.8t 20v with AEB big port head for those interested. Power goal is 300-500whp.

So, my concern is the ABS system of the Spyder and how it would handle bigger brakes. Our legislative organisation that helps in these matters want to see me put bigger diameter and thicker discs. Personally I would like it if they fit under 15 inch wheels.

I do have the option of deleting the ABS but from what I can read even with stock brakes people who have deleted the ABS have major problems with wheel lockups. I don't want that.

What I do want is to fulfill the moronic request of the Swedish legislation, have them fit under 15 inch wheels, keep the abs, have larger and thicker discs, and if possible I wish to be able to fit an aftermarket pedalbox and a brake bias. I'm going to run an electronic throttle body.

I also have the issue of the handbrake, it must be cable operated still.

As of now, my understanding is that I need to keep in mind the ratio of the stock brake system, regarding pedal ratio, the size of master cylinder, the size of the caliper pistons.

Wildwood has come to mind but I wonder if maybe Porsche Boxster brakes or other OEM might do the trick. I have no problem making brackets.

So please, if any of you have knowledge in this matter or can point me towards a good source on information on brakes it would help alot.

Br/nessy

[Ardent]

That is some undertaking.

I recall mention of wildwood but also think you need larger diameter rims to accommodate.

Think it might have been @Dev or @Beachbum957

Searching them and wilwood may render some results.

[boor]

A friend was checking the big brake options and there were not many available, that would have the road legal handbrake option.
Eventually he went with full Willwood kit - front and back with separate handbrake calipers. AFAIK it did passed the test and no issues, bit the price was eye-watering.
There was another option from US, but price after tax was brutal. Don't think that's still avaiable.

[Beachbum957]

There are a few aftermarket brake kits with larger calipers in the US. Most use Wilwood parts. A good place to start is HERE.  I have no personal experience with the company or parts.  

[jvanzyl]

I'm not sure if I'm remembering correctly, but wasn't woodsport looking to develop a new handbrake system for our cars? That way you can go with whatever you want in terms of system and then add his.. the other alternative is fitting the MK2 MR2 hubs and associated brakes, I think they're bigger.

There's a guy over in NZ who's fitted them.

[Nessy]

Thanks alot guys.

Well...

Looks like I have to become an organ donor before my expiration date to afford this.

The stock brake system is really good on these cars. There might be another route to circumvent the issue, Swedish rules state that 4 major modifications have to be carried out in order for the car to pass with a swapped engine. Engine trans and final drive, that's three, and I might get away with a wood sport subframe and modified suspension geometry as the fourth. Let's face it, the zurawski subframe is too expensive and no changes are made to the geometry, and the woodsport one seems to take into account the lowering done by my coilovers. It's a 2000 year model car so I am mindful of changing all the suspension components anyway and adjustable arms are not that more expensive than stock.

[Carolyn]

You could install Prius front calipers.  They are lighter visibly different and  bolt right in.

[Topdownman]

Looks like the Swedish authorities havent seen this video!

Could you do the prius calipers as mentioned above with braided lines and wider tyres to qualify?

[Nessy]

Well I'll be damned. I've been sick with the flu for three weeks, hence the mumbling and excessive pondering.

I had the chance to speak to "my guy" at the organization (non governmental) that preps fellow enthusiasts for their build and registration of the changes.


He said that I can fit any width tyres I want, and the Prius front brake and woodsport subframe in conjunction with some adjustable suspension arms (with dust boots of course) and that SHOULD make the government happy... Should is not a favourite word of mine, especially when I see that I spent 5 hours today just to get the right hand front suspension apart. Funny how the left side loosened in ten minutes.

So anyways, hopefully I can put some more cash into aforementioned chassis upgrades and be content with the Prius brakes.

I'm not sure about the adjustable geometry. I have bought D2 coilovers with pillowballs. If I remember correctly 4.5kg F 7.5kg R
Springs. Should be ok allround for starters.

I've seen battle version, technotoy, Megan, ultra racing, but for me most interesting seems to be uniball.fi , they also go by the name rallydesign and seem to be really knowledgeable. They are in Finland so closer and no orangutang tax.

By the way guys, I'm new here and I don't know if build threads are a thing? I just bought the car when I was hungover, I gave in, then the 2zz gave in 6months later and now I'm just basically jumping head first. Maybe I shouldn't ask so many questions and start separate thread?

[Ardent]

@Nessy

Build threads certainly a thing. 

https://www.mr2roc.org/index.php?board=88.0

[Petrus]

@Nessy

Bigger brakes will not fit within the 15" rims.
The Prius2 front calipers are a straight swap but them having slightly larger piston diameter gives more force on the pads and being aluminium they dissipate more heat.

Concerning springs there are two things to keep in mind:
1. TRD went 100/200 rate difference F/R
2. You need to increase the rear spring rate in line with the load increase

With the engine you will need to think realREAL good about the exhaust as unlike with front engine install, there is only very compact space and you want to avoid heating the engine room. The good news is that a turbo makes for a good muffler, slighly reducing the challenge.

As an observation; I would not want the EA888 2.0 TSI in my MR2. Wáy overkill, especially the torque. It is the latter which breaks traction.

[Nessy]

@Petrus

Thanks for the input.

Not sure what you mean about 100/200 rate diff.

I will be going for Prius brakes and woodsport subframe. Also adjustable arms from rallydesign.

Even when my 2zz swapped roadster was running well, it was a disappointment below 5k rpm. I'm sure more torque will fit me just fine, and I still aim to have a high revving engine, hence the 20valve audi engine in big port config. I will be relocating the battery to the frunk area and will delete the ac compressor for instance. Also the car will have water to air intercooler so there will be some more shift of weight towards the front due to another radiator in the front to compensate the extra weight in the rear which in reality should only be the airwater cooler and a turbo.

Soft top will be deleted and also alot of the interior.

I have very good possibilities to order custom rate springs once it is all together and I want to fine tune things, but that's light-years ahead.... D2 seems to make great coilovers. They have almost same rates as the praised MeisterR coilovers.

Also, I will be running a standalone ECU and will be running e85. With a good tuner I'm sure we can keep torque down if necessary.

[Petrus]

@Petrus

Thanks for the input.

Not sure what you mean about 100/200 rate diff.

Used ´index´ value. I meant to explain double the spring rate rear. Standard it is 50% more rear. Most stiffer after market sets keep thei 50% stiffer rear than front. Doubling the rate will make for a bit quicker handling.
With a heavier engine you would adjust for this.

The 2ZZ has more higher up the scale making it feel relatively gutless lower down. The standard gearing does nothing to help the 2ZZ.

Weight reduction RÚLES!!! Helps with stopping too.

[Nessy]

@Petrus

Yeah I like light...!

This project is alot about trusting the process. It is also very personal and therapeutic for reasons I won't get into.

Any ideas about pads for stock rear and Prius front? Also if there are any slotted discs available in stock size?

[Ardent]

@Nessy

Cannot help you much on the slotted grooved discs, other than to say, I believe there is a good choice.
Cannot recommend any though as I don't like the odd sounds you can get from them.

Pads wise. Very much down to personal preference. The beauty of the prius calipers option presents the same pad choices as standard. The choice of pad based on the real or perceived "bit of extra" provided by the prius calipers, I suspect, is very much in the eye of the beholder.

[Beachbum957]

The OEM and aftermarket spring rates for stock struts listed in many places are mostly estimates or from marketing materials.  When the actual physical springs are measured, the values are different.  One problem is OEM springs are single rate, while aftermarket lowering springs like Tien, Eibach, and H&R are dual rate or progressive.  The other problem is how the springs mount on the strut so the end treatment of the last coils has an impact.  The only true way to measure the spring rate would be in a rig that duplicates the top and bottom mounts.  Some have put OEM springs in a spring tester, but with flat mounting, which gives slightly inaccurate results

When actual springs are measured and some assumptions made on the impact of the end treatments, the OEM springs come out at very close to 61% of the rate of the rear as do both Tein and H&R.  Published values estimate the Eibach at closer to 70%, and the only values found for TTE springs calculates at 60%.

The only springs where the front is at 50% of the rear are published specs for Sportivo springs, both "standard" and sport, but the Sportivo suspension package uses stabilizer bars where the front bar is much stiffer than the rear compared to OEM or Whiteline.  Just a different way to balance roll rate.

Springs for coilovers are different as both mounts are flat and nearly all of the springs are straight rate.  The common values such as 5/7 and 4/6 have the front springs relatively stiffer at 71% and 80%

[Petrus]

The only springs where the front is at 50% of the rear are published specs for Sportivo springs, both "standard" and sport, but the Sportivo suspension package uses stabilizer bars where the front bar is much stiffer than the rear compared to OEM or Whiteline.  Just a different way to balance roll rate.

I have the Sportivo combined with Whiteline in The stiffest setting front which is about on par with the kit.
Also have the much discussed roll center compensating dog bones fitted 
ÁND an effing big rear wing upsettimg all of the above