Location of ECU

X3. Even at a portly(for a Speedster) 2400 pounds, the stock Subaru brakes should really work, as the original car they came from was heavier. Something has to be wrong. Get it checked out, and soon!

X3

I've got discs front and back.  Because they're not power assisted it takes a fair amount of foot pressure to stop quickly, but stop quickly it does!

My 2.2L 137 hp Tubaru also has marginal brakes.  Henry pointed this out rather publicly at a Carlisle gathering after driving the car.  I asked builder Steve, who now puts power disk brakes in his new offerings, if there was a retrofit for my car.  He balked and the situation remains unchanged.  I have tested the brakes at speed and they definitely haul the car down quickly, but locking them up seems to be nearly impossible.   Perhaps it is the relationship between the master and slave cylinders.  The master is made by Wilwood, but the calipers are Delco.  Maybe a mismatch?  I'm no expert, but as with riding my BSA, which also has marginal brakes by today's standards, I stay alert and keep my distance.  

Disk brakes, in general, take a LOT of pedal effort to make them work (and even more to "grab").  That's why they are usually installed with power boosters.  Otherwise, the pedal pressure is a LOT.

 

Simon Hambly did a retrofit on his Speedster (a Chesil, I think) by mounting the hydrovac booster in front of the passenger's feet (in front of the bulkhead) and running the brakes lines over there.  He used a single-circuit "master" cylinder from the pedals to the booster and then a dual-circuit out to the wheels.  Worked like a charm.  Remember, too, that later VW Buses could be bought with a power brake option (for both drums and disks) as well as the Type 3 and 411/412 cars.

 

The only reason I can think of for Steve Lawing balking at doing the upgrade is lack of space to position the booster.

 

That would be my guess. Stuff needs to play nicely together, or kept in separate rooms.

 

There really is something wrong, and it needs to be fixed. Nobody wants to see either of you hurt or worse.

 

My brakes require quite a bit of effort but stop well.  I have standard 4 bolt pattern with 4 wheel disc.  I will also say that I had the same set up on my 1st spyder and that car stopped on a dime with little effort.  Probably since it weighed 500 lbs less.

Disc brakes do require more effort, but the effort should be rewarded by the ability to lock up the brakes. Running right on the edge of lock-up is where the theoretical maximum stopping power is, but lock-up is WAY better than "here's hoping". If you can't lock them up, you can't run on the edge of lock-up or put the car into a full skid.

 

I'm not afraid of a whole lot, but we're already at a pretty big disadvantage being size-tiny and made of glass. Not having the ability to stop would be a deal-breaker for me for sure.

 

PLEASE get them looked at by somebody besides Steve if he won't do anything.

I can easily lock my front (disk) brakes, but the rears (drums) never lock.  I suppose I can adjust them even tighter than the are, but they already drag just a bit.  I don't consider the effort particularly high.  I am running a master cylinder that is intended for 4-wheel disks.  Good?  Bad?

In my first IM I had power booster from a Rabbit or golf with disc brakes all around. 

There is for sure a relationship between your master cylinder, proportioning valve and size of the disk, callipers and number of pistons you have. staying in the same company should help or copying an existing model like a 911, or subie should help if you can get the parts reasonably and they fit. 

 

In the new one I have discs all around with no booster, we had no room and remote boosters only had one circuit rather than two circuits so I chose to not have one, the brakes take a bit more effort but stop very well. The front are 911SC vented the rear are solid disk, Ray

Wow, lots of responses, my original post was not about my brakes, which when anticipating a stop, work very well. However, without power assist, panic stops can be very hairy. My post was to was to remind those upping their hp or going turbo, DON"T forget your freak'n brakes.

 

Lane:  I wouldn't go nuts over this.  80+% of your stopping power is in your front disks and not having your rear drums lock up is more of a good thing than a bad.  Making sure they're working properly is the first priority.  I had one MAJOR panic stop with my F250, fully loaded for a house-swapping trip, pulling the car on her trailer and did a panic stop from 70mph.  NOTHING locked up.  I was pulling on the steering wheel while pushing on the brake and it stopped in a shade under 100 yards (I think...it was pretty tense, there) and I don't remember any squealing or tire smoke.  All I remember were the looks afterward from the two Jack Russell pups like; "Youuuu Dumb Ass!"

 

If it gives you peace of mind, you can check for the existence of a residual valve in the main rear brake line (going from the M/C to the rear brake line "T").  If you don't already have one (and check with Carey - there may already be one in your master cylinder) then you could add, say, a ten pound residual valve in the rear circuit that would then hold the rear shoes a bit closer to the drums in their retracted state and make them a tad more responsive.  My M/C didn't ave one built in, so I added one from Summit Racing.  It seemed to make a small difference in stopping power, but, honestly, I've never been positive about it.

 

But then again, if you've been living with your stopping power for these many miles and are used to the pedal, maybe it's OK.......

 

And to Nolan's point;  If you're going to add 30%-50% more horsepower to your tiny, little, fiberglass car, then you sure as hell should be thinking about much better brakes - like something from a 924/944/911 just to keep from being the first one on the scene of a crash.

Your small 1300 pound car will generate 15 tons of stopping force at the front wheels. Rear brakes are normally configured for a no locking situation, meaning very balanced. The reason is because those rear wheels are holding the car on track while braking, not blocking. In case of a locked front brake your car will simply go side ways until loosing control unless you want to drift on purpose

Its very dangerous without or dis-functional rear brakes. For me it looks like a problem with the dis-proportion of brake fluid volume. I think we all want the best for you so dont play around with brake issues. I can help you with that as soon I have more intel about your brake configuration

Nolan, if you are looking out for me(thanks) I am swapping out to 911SC front end and vented disc like Ray has.

I'll be curious to see how the brakes work on my new IM6, with 911 brakes from a 1987 Carrera, both front and rear.  I do know my set up won't have any power assist, but the stopping should be good, and my leg muscles have not atrophied too much yet. 

 

I exercise them twice a week playing slow pitch baseball...

I don't know exactly how much either John H or Nolan's cars weigh. But I did weigh Rob's green turbo SAS, and it was 2387 pounds. No way is it in the same league as a light Speedster like Lane's or an even lighter Spyder.

I had front disc and rear drum brakes. I just changed to discs all around. Effort is less, and easily modulated so far. I haven't tried to lock them yet, but they do haul the car down a lot faster. No booster needed.

My 2013 SAS turbo coupe weighs 2350 with 16 gallons of fuel.  ABS brakes came with the car.

FYI, for those interested in power assist, if you have room for a master cylinder and booster combination great but in my car I could not so for my build I did a lot of research on brake boosters, and found some remote boosters that could be used in our application except some hot rod boosters that would work would not have full dual circuits braking, making a failure a disastrous future event due to the improper design.  

My old 911 pickup (1970 VW single cab with a warmed over 2.7 Porsche engine and 901 gearbox) didn't have any brake assist (became standard in 1971).  The brakes stopped the truck well during normal stops, but on one occasion I had to stop the truck quickly while driving on the freeway.

To stop the truck in the shortest possible distance I had to use every ounce of strength my leg could muster when pushing down on the brake pedal.  I actually had to use the steering wheel as a support and raise my body part-way off the seat to give me maximum pushing leverage.

I did stop in time (less than five feet the the rear bumper of the car in front of me, but the guy behind me didn't.

 

Bob,

 

I've run 911 discs on all 4 corners of our Speedsters and Spyders and they'll throw you through the windshield if you want...   Good choice.

 

For those with brake issues, keep in mind that there is a lot more to brakes than master cylinder bore.  Pedal ratio plays a huge part, as does the proper matching of volume.  

Here is some very basic math from the manufacturer of our GTS calipers:  http://www.outlawdiscbrakes.com/faq.html

OK, I can sleep easily now that I've got your attention about brakes...

Carey, thanks for the link.

FWIW: my JPS 2332 has discs at all four corners, and John said that they were installed to help me from killing myself w/ the big engine.  I do not know any details of about what is the size of the MC and the discs, etc. but i can tell you that they definitely haul the car down, and do so without undue tension in foot and leg.  I have never had to panic and do a four-wheel lock-up, but I feel as though I have been on that ragged edge a few times.  4X discs are the ONLY way to go, IMHO.  My old A and B coupes had drums and I was never keen on how they worked.  Lots of fade, and the more you used them the more you needed a bigger push.  I think drum brakes were fine for stagecoaches and Model Ts, but really a poor idea for cars going over 60 mph and weighing more than 2,000 lbs.  Just sayin'.  It is amazing to me that they lasted in the industry so long as the only option.

Kelly,

 

You've got the EMPI 4-lug disc kit with the Varga calipers of unknown province. Lot's of EMPI stuff is garbage, but those brakes really work well. It'd be cool if they didn't add an inch to the rear track, but they do.

 

Regardless, they work well.