Ben280

My DTC-30's for AX duty needed a little bit of dragging to feel inspiring in the first corner. But a lightweight car doesn't make warmup easy. Was looking at the PFC stuff the other day, good data point! Squeal isn't a worry for me, but it's good info for comparing manufacturer language against.

Sounds about perfect for what I'm after. The DTC's are ok, but wear like junk and are about as abrasive as 60 grit sandpaper. I've got Wilwood calipers front and rear, so a fairly common pad shape. Might look to upgrade as I start adding aero since I'm using rather small calipers. Only reason to upgrade there would be a thicker rotor, but I'm using a 12x.81" rotor up front. Rears are rather thin and after their visit to the track turned mostly blue haha!

I figure if I can get the car to feel really nice for 2-3 hot laps in a row, that's about all I need for a time trial type event. There's a fine line for me between going fast and burning the car down during a 20 minute session. I've tried Hawk Blacks, and they were pretty good, but I like the bite and modularity of the DTC-30s more. I might try the DTC-60's but I've also heard that Hawk has been left in the dust technology wise by other companies at this point, and the torque their pad compounds can put out just are nowhere near what other tech can do. Need to research this more, but I've heard enough to be interested. I'll note too that the Hawk Black brake dust is about the most corrosive thing I've ever seen. Don't even think about getting it wet or it will permanently bond and etch into aluminum.

Just cooked the pads and got some serious heat into the system. No brake cooling to speak of, which with wheels this small and wide is a real problem. The pedal felt alright, but the brake feel just didn't instill the confidence I wanted. I need to do some research and probably some testing to find something that I like. Water and Oil temps were a bigger problem, I could get about 3 hot laps before temps were too high.

Getting back to racing, and had a couple of events already. First up was SCCA Time Trials National Tour at The Ridge Motorsports Park up in Shelton Washington. First time at that track, and first time on track in about 6 years, so I wasn't about to light the world on fire, but I managed to go sub 2 minutes, which was the goal for the weekend. I did swap out my lightweight autox front hub arrangement (T3 aluminum hubs, custom hats and scalloped rotors) in favor of a full vented rotor and OEM steel hubs. Figured additional thermal mass would be good, and I was right. Still need to work on brake cooling, and cooling in general for future events. My auto-x gearing meant that I was on the limiter in 4th for a good chunk on the front straight. When I go back, I'll likely swap out some of the trans gears to try and optimize those ratios. Anyway, video here: This past weekend was back to Auto-x, so I swapped out the front hubs, swapped back the brake compounds, replaced a corded front tire, and went racin! I was using the usual Hawk DTC-30 on the track, but have been messing around with the Hawk HP+ pads for auto-x, hoping for a bit less need for warm-up. Well the HP+ suck, and I'm throwing them in the garbage tomorrow! Just really numb, bad release, and no real initial bite. It was also fairly cold, and my tires were having issues getting up to temp, I've been really thinking about switching up a couple things in the car after August, so wheels and tires might make the list. Anyway, best time from Sunday, when we finally got the tire to be over ambient temp! Reasonable time, but should have been 3 seconds or so faster on this course. Always more work to do!

I feel like these wild mish-mash collections of parts are from people looking to convenience over a proper engineered solution. Brakes need to be viewed as a cohesive F-R system, I'm surprised that more companies haven't taken the example from Z car garage (and really everyone else) and offers a full brake system. It's not witchcraft, unless you're trying to use maxima rear brackets and stuff you can find at pick n pull Lots of talk here lately about a need for documentation. Is this a new concern? I feel like nobody has offered it really in the past 10 years, so what's spurring this now?

Makes sense now, I was trying to imagine how this would work with the factory rear uprights! Watch your roll center as 260DET said, you can easily get into trouble and the car will behave terribly. Since you're already welding in camber plates, good enough time to add some reinforcement up there, although I think if you try and get too vertical, you'll start hitting your springs on the inside of the shock towers.

Thanks for posting! Cool to see some of the principles of intake tuning in action, namely, longer runners pushing the powerband lower at the expense of total HP, the 205mm had the earliest power spike with a lower overall number! Good stuff to keep in mind when looking at intakes for triple carbs and ITB's!

Just when I thought this build couldn't get any cooler, you throw Motec and a dang HGT box at it!?

Cool! For some reason I thought you got a 550. Should make it easy for troubleshooting!

@DuffyMahoneyHow are your injectors wired into the ECU? If i'm not mistaken there are only 4 injector drivers on the haltech board. Are you running 2 batches of 3 injectors? I seem to remember from a few pages back you got a CAS dizzy piece so you'd have a cam signal heading to the ECU for a more sequential system.

Haltech's are a bit different than the MS3 I use, but the injector timing sounds to be fairly out of joint from Duffy's video. If the crank sensor is bad, inconsistent or just something the computer can't figure out, the MS would either not start, or show errors in the Sync gauge. I doubt the Haltech would try an muddle through a bad cranking trigger. I the trigger and home wires are also shielded bundles in the Haltech wiring harness, so unless Duffy isn't using those, noise shouldn't be an issue either. Injectors are behaving badly at a minimum, I'm interested to hear what the report on them is!

It sounds to me like Madkaw has a prop valve installed in the rear circuit, and has it dialed all the way down. You can only "bias" a dual master cylinder system, otherwise you are proportioning the amount of force to the rear. This would be mostly in line with what OP had to do. Would be helpful to know the model Wilwoods you are using, as saying you are running Wilwoods all around is just like saying "I run calipers all around". If you know the MC size and the size of your pistons in the caliper, you can do some pretty simple math to tell you where you should be, and how much prop valve you need to throw at it.

That sounds to me like a few injectors are just going fully open above 1300rpm. I'll be interested to hear what the injector lab place says about them. Were you logging data on the ECU? Should be reasonably easy to see if you had trigger errors or a bad sensor. Good thing to check, but I don't think it's the root cause of your issue here. Another thing would be to try installing a dummy injector and see if you can run through the test modes on the ECU to confirm the ECU is at least sending a good command.

The erratic crank angle signal that would make the injectors that out of whack would result in a no-start condition on an ECU like the Haltech. My money is on the windings in the injectors. ECU might be the issue, but the voltage requirements of a low impedance injector should be within what is possible from the Haltech. Also, just to address some of the statements earlier, the Low/High resistance is a bit of a misnomer. The low impedance injectors, also called "Peak Hold" have a much higher opening voltage, and keep the injector at a base voltage while running. They'll send the injector a 2-4v signal, then sit at 1-2v. High Impedance injectors, also called "Saturated" are a simple on-off signal, at 0.5-1v. Hence how a "High" injector can be overpowered and burnt out by a "Low" signal.