Sams Polo 3.0

[Sydneykid]

Oh believe me despite being still a road car I have toyed with the idea of scrapping the ABS system. I dont think it'd be a good look if I was ever caught that way though.

Well...................most people wouldn't know where the ABS unit should be, let alone what it looks like, additions are easy to spot, deletions require knowledge of that particular vehicle.

You could leave it in place and just bypass the plumbing. Make it easily removable for the weight saving when required.

Cheers
Gary

[sambb]

I have seen in places (mostly subaru forums) where guys just pull the ABS fuse . The fronts then work through the ABS module as per normal because the module without power is in pass through (you need a good diagram of the module to know that the solenoids would be in and stay in that state though). Similar to what I found when I pulled the ABS fuse their rear biasing went nuts so then run the rear port of the MC rearward via a proportioning valve on a single line before it splits to each rear corner. ABS module stays in place and pipe work stays attached whether its void or not for OEM appearance. A piece of black electrical tape goes over the ABS fault light on the dash ha ha. By killing the ABS/ESP I can then run the Audi S3 hubs that I have with their huge roll centre correction as what looks to be a mechanical plug n play.
I maybe just may have a shot at getting my Dads old car as a daily. If that comes through I'll keep mine as a road registered track car and go engineered 2 seater with half cage and then will definitely do something like this with the brakes. So it'd still need to be stock looking - no pedal boxes etc even at that stage. Whether it stays a daily or goes to registered track duties, either way I need a bigger master cyl.

[Stuwey]

Sam, have you tried bleeding the system at *every* line connection?

I was having troubles with my mini getting a decent pedal and cracked the sads with it and started from the master and eventually every point along the way.

3 months of frustration cleared up in two hours.

I know it shouldn't have needed it, but that's what sorted it in the end.

[sambb]

You mean at the ABS module inputs, then its outputs, then at each brakes corner. No I havent done it at each connection along the way. I have checked each connection for fluid leaks though, but havent had the stomach to go right through it like that. But yeah maybe I should. After a full flush recently I got it half decent/driveable and then paid for a proper pressurised vag.com pulsed ABS module bleed. Then after my first track day on that fluid I gave it a few good ABS stops (which definitely hardens up the pedal for a while) and brought it straight into the garage for another go with my vacuum bleeder at each corner in case some track day air/burnt fluid had accumulated at the calipers. So short of what you suggested, it should be in pretty good shape. I know a lot of stock is put into incorrect bleeding being the source of the problem with these cars but also I've now had 3 polo's since 2014 and they are all the same. They have all had configurations of different pads, fluids, calipers and despite that were/are all fundamentally the same RE the pedal. This car even with master cylinder braces and caliper stiffeners isn't one iota better than all the others. Its got to be something inherent in the design. I just dont know what.
To me the ABS modules are either programmed to behave in that way, like Gary has said are just always bypassing OR the master cylinder is ridiculously underdone.
After trying a different soft coding on the ABS module the other night the module has wigged out. I get ABS and ESP CEL's. The ABS light clears after a bit of driving leaving the ESP symbol on. Says there's a comms error even though the soft coding is back to normal. Despite the errors the ABS is still working?! Who knows maybe whatever state the ABS has defaulted to is better than what its coded for? As long as its not locking the rears which it was when I pulled the ABS fuse, then i'll just keep driving it till I find a solution. I barely even care anymore. I am that close to just stripping it all out and paying someone to come around and plumb the whole car up like its from 1989. Or run sans ABS fuse with a proportioning valve in the rearward line to correct the rear biasing. I mean you put so much effort into getting it to go hard and be reliable and at the end of the day you have a car on the track that you just dont trust in the braking department. Either ESP hammering away at the brakes when you are going 80% or the pedal literally ABS'ing its way to the floor when you have to avoid something on the circuit yet the cars rate of decel is about half of what you could achieve without it. I'm starting to passionately hate all the tech on these things. If I ever get another Polo its going to be pre nanny modules, naturally aspirated on R1 bike carbs with a standalone ignition computer. I want my RS2000 Escort/Celica RA23 GT/Pug 205 gti back!!

[Eddy]

Hoyhoy.

I don't know as to what is going on with the brakes Sam, as the best mod I ever done was the master cylinder brace, to me the difference was fantastic.

[sambb]

No it’s not on you Eddy. Like I said it’s not this car alone. It could be that something has degraded a bit since you last tracked it in anger but I doubt it. All my polos have been like this RE long pedals, vague feel and premature ABS intervention. I think I got used to it over time plus also mostly did hillclimbs initially so it didn’t really show up that drastically. A mate drove my last polo pretty hard through a national park and then pulled over certain he’d stuffed the brakes. It’s was the ABS pulsing and sinking the pedal down at speeds that wouldn’t even have his Clio troubled. He was saying that he couldn’t believe I drive the car flat out like that. I hadn’t really even thought about it much before then. After doing more circuit stuff it’s now getting disconcerting. My gut says it’s the master cyl but also It could be the ABS unit but I don’t want to stump for the latter to no avail, and even if it did improve the pedal at the end of the day im still stuck with the ABS. If I’m going to spend that kind of coin that’s where I’m thinking I’d rather just go with a reworked non ABS system that I can build upon. Going to look into the cost of doing that and if it’s even possible with the engine still in the car! The car has enough grunt it’s just tyres and brakes that are top of the list now. I’ll have time on my hands I suppose. This Sydney lockdown is getting pretty heavy now.

[Sydneykid]

My suggestions, go for the larger master cylinder, I think it needs it anyway and there is a power booster so it will increase the pedal effort which is not a bad thing, but not make it too heavy.

Bypassing the ABS unit is easy (well it has been on the cars that I have done), there are fundamentally 2 fluid inputs from the master cylinder and 4 fluid outputs to the wheels. I use as much of the standard pipework as possible, basically just bypassing the ABS unit itself. I use braided lines, with appropriate fittings, sparingly to complete the linking, as it can get expensive. That and a couple of generic 3 way blocks to do the joining.

When we get out of this lock down more that happy to catch up at the race workshop and we will have a look at it and make some suggestions. You can have a look over the Honda if you like, it has all the good tricks that you can pinch ideas from. Justin is also really good at motorsport fluid connections, so he will have plenty of options to suggest.

Cheers
Gary

[sambb]

Yeah that'd be good Gary. From what I can gather to run a street approved type setup, each master cylinder port would run to a tee that would tie diagonal fronts and rears together. For the life of me I cant figure out how you proportion that though. Having one master cylinder port for the fronts and one for the rears with the rear proportioned before it split to each corner seems like the most workable though.
I'm only hesitant at what kind of wobbly the ABS/ESP will throw. It'd definitely need to stay plugged in (no weight saving) as without the wheel speed sensors I'd loose dash info. But I'd love to go to the S3/TT front hubs that use different sensors so there's an issue there. Wonder if the 4 wheel speed sensor inputs to the module could just be parralleled off say one of the wheel speed sensors, so that the module doesnt know any different.

[sambb]

On a good note, the new oil cooler setup - different to previous in that it now runs a T-stat sandwich plate and the cooler core is blanked off on the street - is running the oil temps right in the good 90-100 window now. Oil temps now run higher than water temps in normal driving. As a result the catch can is for the first time catching plenty of water. To my mind that means the oil is getting to a temp to evaporate out any water contamination and the crankcase water content is coming out as a gas and being caught/condensed in the can. Better out than in. If I run the catch can system with the PCV connected you dont see as much water in the can as it most likely just gets drawn into the inlet manifold under vacuum as a gas. But if the PCV valve is blocked off and the catch can is only TIP connected, then you see plenty of water caught. Yes there's always going to be more water caught in the cold weather but either way it wasnt even
doing this when the oil temps were so low before.

[Sydneykid]

Yeah that'd be good Gary. From what I can gather to run a street approved type setup, each master cylinder port would run to a tee that would tie diagonal fronts and rears together. For the life of me I cant figure out how you proportion that though. Having one master cylinder port for the fronts and one for the rears with the rear proportioned before it split to each corner seems like the most workable though.

For the diagonal split you could run 2 proportioning valves, one each between the front and rear wheels. Obviously only one required when the split is front / rear.

We use the Tilton ones, they have 7 settings, so it would be easy to keep them the same setting, the infinite adjustment screw type would be much harder.

I'm only hesitant at what kind of wobbly the ABS/ESP will throw. It'd definitely need to stay plugged in (no weight saving) as without the wheel speed sensors I'd loose dash info. But I'd love to go to the S3/TT front hubs that use different sensors so there's an issue there. Wonder if the 4 wheel speed sensor inputs to the module could just be parralleled off say one of the wheel speed sensors, so that the module doesnt know any different.

Welcome to the world of Production Car Racing, it's brain ache on the BM's when the windscreen wipers won't work if you disable the traction control. They talk to each other via the Can Bus and the traction control + torque split settings depend on how fast the wipers are wiping.

Cheers
Gary