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PostPosted: Tue Feb 16, 2021 9:14 pm 
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Ok, Here's the thing. it must be a VERY long time since i've driven a completely stock Sprint. Some close to standard, but with extra horses added or bigger tyres. A considerable number on TJs. Most on some variation of all 3 or with other mods included. Obviously I do most of my miles in a Dolomite shaped car that the factory boys would barely recognise.

When I first built the Carledo, it was intended as a drag racer that I drove to the strip, so brakes weren't a major consideration, "adequate" was good enough. Even so, I did it properly, all new braking system derived from a Sprint mostly, with Greenstuff pads, Goodridge hoses and DOT5.1 race fluid. I also went to dual circuit, initially, I admit, just because I could and why not? The car already had it's 6x15 MGF alloys shod with 195/50 Toyo Proxes so I had decent grip from day 1.

Although the car stopped well enough and aced the rollers on every MOT, it just never FELT quite right and I don't know how to describe the wrongness. The pedal was just a touch soggy for my taste and the feeling I got in the seat of my pants was one of insecurity, as if the car was just waiting for a chance to mess with my brain. Somehow I just didn't TRUST them. I KNEW it was nonsense, i'd built it up myself and KNEW there was nothing wrong. Still the feeling persisted.

I fitted a pressure reg to the rears after a wet road rear lockup (no LSV, my mistake, the scrap Sprint I robbed the axle and brakes from didn't have one) that helped a bit but not much. I ditched the PDWA (it came with the dual circuit master, so I fitted it) cos I got fed up with it putting the light on when nothing was wrong, again no major improvement. Then I took it to it's first trackday, Prodrive it was, at Star90 in 2013 and learned all about fade! 3 hot laps of the short (1.5 mile) Prodrive circuit and I boiled the fluid! It was this that led me to the TJs, along with the fact I had so much fun I wanted to do more trackdays!

Once I fitted the TJs, I knew what i'd been missing, they inspired a confidence in me that no amount of tinkering with the originals could achieve. Gone was the soggy pedal and the distrust with it. And it seemed to me that the car DID stop better, though this MAY have been psychosomatic as I was always a bit leery of really standing on the anchors in original form.

Be that as it may, I've driven dozens of other Dolomites of all outputs since and those with standard type brakes always give me the same insecure feeling. Some of those others, it turned out I had good reason for my insecurity! Spoilt? Possibly! But not by ABS or other mod cons, by the TJs!

It's not very scientific I know, but I TRUST the seat of my pants, it may be why i'm still relatively unscathed after so many years of hooning around!

Steve

_________________
'73 2 door Toledo with Vauxhall Carlton 2.0 8v engine (The Carledo)
'78 Sprint Auto with Vauxhall Omega 2.2 16v engine (The Dolomega)
'72 Triumph 1500FWD in Slate Grey, Now with RWD and Carledo powertrain!

Maverick Triumph, Servicing, Repairs, Electrical, Recomissioning, MOT prep, Trackerjack brake fitting service.
Apprentice served Triumph Specialist for 50 years. PM for more info or quotes.


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PostPosted: Thu Feb 18, 2021 3:46 pm 
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Location: St Annes on Sea, Lancs.
While I, personally, don't think there's a need to modify the brakes on a standard Sprint unless you've significantly increased the grip, I understand that others might. I get no feelings of insecurity, but it is an unmodified, standard car on standard spec tires. And since I fixed the servo, albeit with a downgrade, it's fine.

That I can get the Sprint to easily lock the front wheels at 30 mph with standard cars on standard spec tires, even with an 1850 servo, says to me that it should be possible for nearly anyone with well maintained brakes. It will be bit harder to lock the wheels at higher speed as (rubber not being a simple solid) the maximum coefficient of friction from hysteresis increases a bit with road speed (but so does the ideal slip ratio, so the component from adhesion goes down some, if not by as much - guess who's been into ResearchGate a bit). But that (whether the details are right or wrong) is again a function of the tires. So it's still the case that if the standard brakes can get you to the maximum brake force, bigger brakes just make it easier to get there and easier to get past and lock up as well. The corollary of that is they make it harder not to lock up when grip is in short supply. But then every silver lining has a cloud.

But I don't doubt there'll continue to be customers for front brake upgrades, even to standard cars.

And I still go back to the point that there are more ways to adversely affect the balance of the brakes than you might think - even it seems when driving in the wet.

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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PostPosted: Sat Feb 20, 2021 9:54 pm 
Oh, I started something there. All that theory took me back Mechanics lectures at South Shields Marine & Tech in the 1960s. I've forgotten most of it as well!

So, bearing in mind that I've got a 200 hp V8 in my Dolomite what do the experts think I should do with my brakes please?


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PostPosted: Sat Feb 20, 2021 11:53 pm 
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Location: Northwich
Quote:
....Mechanics lectures at South Shields Marine & Tech in the 1960s......
.....what do the experts think I should do with my brakes please?
Oh no, not a Sand Dancer! 🙈😉

Deffo a Trackerjack conversion. I track my car and Hillclimb and Sprint it and never had a second's worry. I more than recommend them and deffo concur with Steve's thoughts. There's no better system out there! 👍


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PostPosted: Sun Feb 21, 2021 10:00 am 
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Oh, I started something there. All that theory took me back Mechanics lectures at South Shields Marine & Tech in the 1960s. I've forgotten most of it as well!

So, bearing in mind that I've got a 200 hp V8 in my Dolomite what do the experts think I should do with my brakes please?
Realistically? And no fade (without seriously trying)?
I would say bigger discs than the normal Trackerjack, but will need larger wheels too.
Have a look at other older 200bhp lightish cars (not that many about!) Sierra cossie is 220 as std, and had 280mm discs. But would need 15" wheels (or maybe 16?) Something around 260 should fit under a 14" wheel, I am probably going to use 256mm golf discs.
Everybody who has fitted the TJ brakes is mighty happy with them. Good enough for me.

_________________
Clive Senior
Brighton


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PostPosted: Sun Feb 21, 2021 11:16 am 
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Joined: Mon Dec 12, 2016 9:53 pm
Posts: 1699
Location: Harrow Middlesex
You could go Wilwood 4 pot calipers but they are dear,for value for money go Trackerjack set up,im using 260mm disc on mine and have gone to 14 inch wheels

I have a set of 15 inch wheels for sale

Dave


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PostPosted: Sun Feb 21, 2021 3:07 pm 
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Posts: 960
Location: Sutton,Surrey.
Quote:
Oh, I started something there. All that theory took me back Mechanics lectures at South Shields Marine & Tech in the 1960s. I've forgotten most of it as well!

So, bearing in mind that I've got a 200 hp V8 in my Dolomite what do the experts think I should do with my brakes please?
What spec is the Rover Engine?
Quote:


[quote=pfg49 post_id=335823 time=<a href="tel:1613858069">1613858069</a> user_id=15749]
Oh, I started something there. All that theory took me back Mechanics lectures at South Shields Marine & Tech in the 1960s. I've forgotten most of it as well!

So, bearing in mind that I've got a 200 hp V8 in my Dolomite what do the experts think I should do with my brakes please?
Realistically? And no fade (without seriously trying)?
I would say bigger discs than the normal Trackerjack, but will need larger wheels too.
Have a look at other older 200bhp lightish cars (not that many about!) Sierra cossie is 220 as std, and had 280mm discs. But would need 15" wheels (or maybe 16?) Something around 260 should fit under a 14" wheel, I am probably going to use 256mm golf discs.
Everybody who has fitted the TJ brakes is mighty happy with them. Good enough for me.
[/quote]

What wheels are they and PCD

_________________
2009 Mini Clubman Cooper S Daily Driver.
1980 Dolomite Sprint with a touch of BLTS
Balanced Lightened and Tweaked 13B Rotary and SuperCharged.
Back in my possession 22 September 2019.
Rebuilding the Sprint time taken so far, 111Hrs@15/12/2020
212Hrs @31/12/2021
352 @ 28/11/2022
455Hrs @ 20/10/2023
480Hrs @ 14/03/2024
This is time taken at the Sprint not necessary time worked.

Working on a ratio of just 7Hrs a day not including driving to the Sprint.
That equals to 68 days that doesn’t include weekends.
Member TDC no 0471

Project 13B Sprint now back on.


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PostPosted: Sun Feb 21, 2021 5:54 pm 
What spec is the Rover Engine?

I haven't got a clue to be honest! When I bought the car, it wouldn't run unless you held the choke flap shut on the 390 Holley. Tried all sorts to get it to run but no luck, so down to my pal's rolling road where we decided that the carb had been dismantled and put together wrong/bits missing/both. The carb was strange anyway because it was very heavy, made of something that was not aluminium. So my pal suggested a new carb because small Holleys are cheap. Not anymore they aren't even if you can find one. So I bought a new Chinese one for £200! This worked fine, jetted up, just under 200bhp @ flywheel. Back to the workshop lots of other things to do, so on we go. Then a couple of weeks later I needed to move the car, and I noticed a smell of petrol. Looked in the window in the primary float chamber, and the fuel level was nowhere to be seen. Off with the primary float chamber and one of the allen bolts snapped, and the float had a hole on it cos it was full of petrol. (why is it no matter what you do the petrol will NOT come back out of the float?) Fortunately the bolt snapped leaving about 1/4" proud, so I was able to get a grip on it. Unfortunately when I gripped it snapped again about 1/2" into the. hole! drill a hole through the bolt for a stud extractor.... you know what's coming next.... the stud extractor snapped! Now I've got big trouble, cos you can't drill them out. So we welded a nut to the snapped extractor, and I guess the heat helped, as out it came. Eventually we got the rest of the bolt out and discover it's no normal UNC thread, no, It's a 12-24, which I didn't know existed, and finding one 2 3/4" long was fun. New unsinkable float, back together running fine. Moral of the story is, don't buy cheap Chinese carbs for about a quarter of the price of the original, and not expect to have problems. I really should know this by now!

And yes Shaun, I am indeed a proud Sand Dancer. together with my lovely wife, Mrs Sand Dancer :lol:


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PostPosted: Sun Feb 21, 2021 5:59 pm 
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Joined: Sun Oct 26, 2008 7:26 am
Posts: 2473
Quote:
[
What wheels are they and PCD
Me? I have some compomotive crosspoke type wheels, offset looks workable. I have a set of minilite reps on my spit that have been on my Toledo which work well (great on the RBRR with crossclimates). I have also run MGF alloys at 15". A cheap option.

_________________
Clive Senior
Brighton


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PostPosted: Sun Feb 21, 2021 8:07 pm 
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TDC Shropshire Area Organiser

Joined: Sun Aug 21, 2011 5:12 pm
Posts: 7013
Location: Highley, Shropshire
Quote:
Quote:
Oh, I started something there. All that theory took me back Mechanics lectures at South Shields Marine & Tech in the 1960s. I've forgotten most of it as well!

So, bearing in mind that I've got a 200 hp V8 in my Dolomite what do the experts think I should do with my brakes please?
Realistically? And no fade (without seriously trying)?
I would say bigger discs than the normal Trackerjack, but will need larger wheels too.
Have a look at other older 200bhp lightish cars (not that many about!) Sierra cossie is 220 as std, and had 280mm discs. But would need 15" wheels (or maybe 16?) Something around 260 should fit under a 14" wheel, I am probably going to use 256mm golf discs.
Everybody who has fitted the TJ brakes is mighty happy with them. Good enough for me.
The standard TJ disc (Golf) is 239mm, this is more than enough for a well sorted trackday Sprint with 180ish horses.

It's also the biggest disc you can fit and still use the Sprint alloy wheels (literally, it's millimeter perfect, especially when first fitted with brand new pads you need feeler guages to measure the gaps and sometimes have to shave a tad off the outside of the calipers)

Ever the experimenter, I have built a bigger kit for my own Sprint auto with Vauxhall motor, which uses 256mm Passat discs and 1.7 Puma calipers and carriers with the standard TJ adaptor brackets. The discs are modified exactly the same as the Golf discs in the standard kit, so everything is relatively easy to do. My bespoke adaptor flexi hoses also still fit this bigger setup. The only downside, if you consider it one, is that the car will no longer accept the 13" Sprint alloys, i'm using 5.5 x 14 fake Minilites in the TR7 ET of 27mm which clear the brakes comfortably. Anything bigger is, of course, no problem at all.

Image

Image

Image

Steve

_________________
'73 2 door Toledo with Vauxhall Carlton 2.0 8v engine (The Carledo)
'78 Sprint Auto with Vauxhall Omega 2.2 16v engine (The Dolomega)
'72 Triumph 1500FWD in Slate Grey, Now with RWD and Carledo powertrain!

Maverick Triumph, Servicing, Repairs, Electrical, Recomissioning, MOT prep, Trackerjack brake fitting service.
Apprentice served Triumph Specialist for 50 years. PM for more info or quotes.


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PostPosted: Sun Feb 21, 2021 8:38 pm 
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Joined: Mon Dec 12, 2016 9:53 pm
Posts: 1699
Location: Harrow Middlesex
Quote:
Quote:
Quote:
Oh, I started something there. All that theory took me back Mechanics lectures at South Shields Marine & Tech in the 1960s. I've forgotten most of it as well!

So, bearing in mind that I've got a 200 hp V8 in my Dolomite what do the experts think I should do with my brakes please?
Realistically? And no fade (without seriously trying)?
I would say bigger discs than the normal Trackerjack, but will need larger wheels too.
Have a look at other older 200bhp lightish cars (not that many about!) Sierra cossie is 220 as std, and had 280mm discs. But would need 15" wheels (or maybe 16?) Something around 260 should fit under a 14" wheel, I am probably going to use 256mm golf discs.
Everybody who has fitted the TJ brakes is mighty happy with them. Good enough for me.
The standard TJ disc (Golf) is 239mm, this is more than enough for a well sorted trackday Sprint with 180ish horses.

It's also the biggest disc you can fit and still use the Sprint alloy wheels (literally, it's millimeter perfect, especially when first fitted with brand new pads you need feeler guages to measure the gaps and sometimes have to shave a tad off the outside of the calipers)

Ever the experimenter, I have built a bigger kit for my own Sprint auto with Vauxhall motor, which uses 256mm Passat discs and 1.7 Puma calipers and carriers with the standard TJ adaptor brackets. The discs are modified exactly the same as the Golf discs in the standard kit, so everything is relatively easy to do. My bespoke adaptor flexi hoses also still fit this bigger setup. The only downside, if you consider it one, is that the car will no longer accept the 13" Sprint alloys, i'm using 5.5 x 14 fake Minilites in the TR7 ET of 27mm which clear the brakes comfortably. Anything bigger is, of course, no problem at all.

Image

Image

Image

Steve
my setup is similar to Steves citroen picasso 260mm disc and 1.7 puma calipers the standard trackerjack brackets still fit,im using 14 inch wheels

Dave


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PostPosted: Sun Feb 21, 2021 9:35 pm 
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Joined: Sun Nov 16, 2014 12:46 am
Posts: 424
Location: Midhurst, West Sussex.
I have got the standard GTI trackerjack kit for my car, which I can see I am going to have to upgrade at some point. It's a Nissan CA18DET going into it with a hybrid T25 turbo, so it should be about 230 BHP. My plan is to get the car up and running with this brake set up, then upgrade the brakes/wheels/tyres later on.

Does anyone know if the larger Passat discs are a big improvement over the GTI ones?


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PostPosted: Sun Feb 21, 2021 10:58 pm 
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Joined: Mon Dec 12, 2016 9:53 pm
Posts: 1699
Location: Harrow Middlesex
Quote:
I have got the standard GTI trackerjack kit for my car, which I can see I am going to have to upgrade at some point. It's a Nissan CA18DET going into it with a hybrid T25 turbo, so it should be about 230 BHP. My plan is to get the car up and running with this brake set up, then upgrade the brakes/wheels/tyres later on.

Does anyone know if the larger Passat discs are a big improvement over the GTI ones?
yes the bigger disc help,but the 1.7 puma calipers have a bigger piston size

what brake calipers are you using

Dave


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PostPosted: Mon Feb 22, 2021 12:14 am 
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TDC Shropshire Area Organiser

Joined: Sun Aug 21, 2011 5:12 pm
Posts: 7013
Location: Highley, Shropshire
Quote:
I have got the standard GTI trackerjack kit for my car, which I can see I am going to have to upgrade at some point. It's a Nissan CA18DET going into it with a hybrid T25 turbo, so it should be about 230 BHP. My plan is to get the car up and running with this brake set up, then upgrade the brakes/wheels/tyres later on.

Does anyone know if the larger Passat discs are a big improvement over the GTI ones?
The point of bigger dia discs (as Graham will tell you) is to move the piston centres outboard. My mod only moves these centres an extra 8.5mm further out which doesn't seem like a lot, but the effects are not linear, they are exponential. I haven't worked it out exactly, but it's about the same again as going from stock to TJs. So I expect a decent return for my investment. As it's only travelled a few hundred yards under it's own power so far (making sure the ecu controlled trans shifts properly) I can't yet say exactly HOW much better. But as Graham says and I agree, you CAN make the brakes TOO good! I'd try the car with the normal 239mm discs first and see how you get on with it. Car weight is also a factor, are you running it fully trimmed or as a stripped out racer? The Carledo is down to a kerb weight of 760kg (+82kg of ME) to make the most of it's miserable 140odd horses, but the standard 239mm TJs are fine with that, no fade at all and consistent stopping, from a ton or a bit more, for a full days track use at Castle Coombe. The MOT brake testing weight (including driver, spare wheel, tools, half a tank of gas and "accumulated road dirt" for a standard, fully trimmed Sprint is something like 1270kg IIRC. That's a big difference!

To Dave, the Puma calipers are the same 54mm dia pistons as the Sierra ones on the original TJ design (standard Sprint is 48mm) It's moving them outboard that makes the difference (see above) Keeping the same size piston is important to avoid the "long pedal" induced by increasing piston size, the 54s are enough! Any bigger and you'd need to find a bigger bore master cylinder to compensate.

Incidentally, whilst researching the calipers I wanted to use, I discovered that many of them are pretty much identical and interchangeable, it's the caliper carriers that vary from model to model and by disc dia and sometimes pad shape. One of the reasons I picked the Puma ones (apart from the fact that I HAD some) is that they run a larger area pad than most of the similar Ka, Fiesta, Sierra and Escort models. In braking efficiency terms that's no real advantage, but bigger pads will run a tad cooler and last longer in service (OK, i'm tight, sue me) I see it as a positive with my pad hungry automatic car.

Steve

_________________
'73 2 door Toledo with Vauxhall Carlton 2.0 8v engine (The Carledo)
'78 Sprint Auto with Vauxhall Omega 2.2 16v engine (The Dolomega)
'72 Triumph 1500FWD in Slate Grey, Now with RWD and Carledo powertrain!

Maverick Triumph, Servicing, Repairs, Electrical, Recomissioning, MOT prep, Trackerjack brake fitting service.
Apprentice served Triumph Specialist for 50 years. PM for more info or quotes.


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PostPosted: Mon Feb 22, 2021 1:10 am 
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Joined: Sun Apr 06, 2014 10:49 pm
Posts: 967
Location: Northwich
Quote:
And yes Shaun, I am indeed a proud Sand Dancer. together with my lovely wife, Mrs Sand Dancer :lol:
Excellent stuff! Regards to Mrs. SD! 👍

Did you ever study at Sunderland Poly BTW? I was there in the early 90's and they still had a Naval Architecture dept which looked really interesting to us Mechanicals, but it was soon shut down unfortunately.


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