GTE valver fast road/track car project

[BlackBox]

Re: GTE valver fast road/track car project

If so my belief is:

small bore m/c same travel/same pedal pressure = less fluid higher pressure
large bore m/c same travel/same pedal pressure = more fluid lower pressure

The difference is probably so minimal that the main consideration is can the m/c provide enough fluid without resorting to a long travel to provide the extra (although small) amount of fluid to charge the larger area of all the calliper chambers under breaking?

I'll not get into expansion and fluid breakdown as it heats up or we will be here all day .....


Laurie.

Your theory sounds right to me

smaller bore m/c = more travel/less pedal pressure = more sensitive braking

I recently tried two different brake calipers, single pot sliding type. I forget exactly the piston dimeters but one was about 52mm and the other 55mm dia.
The difference in braking was phenomenal, the caliper larger piston was so sharp they scared me in a panic braking scenario and they were removed with the smaller ones being put back on.

[Harvey]

Re: GTE valver fast road/track car project

Ben - I didn't think about the sliding effect of the ATE caliper. Keeping this at a high level; A fixed caliper with two pistons at half the diameter of a single piston would offer the same braking efficiency as a single sliding caliper would it not?!?! This would mean that doubling the calculated piston area of a single sliding calipers setup isn't right. I suggest with your pedal box that you go for a .625 for the fronts and .750 for the rear to help balance out the braking to the fronts. You might also consider an in-line bias for the rear to bias even less to them. Might be worth speaking with some motorsport companies to ask what they use as some race cars run huge front calipers and must get round the issue that you had with you large front 4 pots.

Regarding ATE piston diameters the stock 256mm caliper has it stamped on the top of the caliper body 52/24 meaning it's a 52mm piston and a 24mm width disk. The 288mm and 308mm V6 caliper has 56/25 stamped on it meaning it uses a 56mm piston and a 25mm width disk. I believe the early GMF sliding caliper on the 1.8 GTE uses a 48/20 so 48mm piston and 20mm width disk, however the disk diameter was smaller and used a 236mm and not the 256mm as fitted to the later cars. I hope this info helps.

Laurie - I agree with your comments and your 'special' formula as you have said I'm just discussing this at a high level so no requirement to go into huge detail, les keep this very basic.

[RallyMarshal]

Re: GTE valver fast road/track car project

The rallycar uses std 256mm ATE 16v calipers (albeit with motorsport pads) and has the std 16v rear discs fitted (albeit with shitty pads) and I do have the bias forwards but thats with moulded slicks that generate a lot of braking grip. I have a .625 front and a .7 rear fitted at the moment.

Paul..

[DarrenH]

Re: GTE valver fast road/track car project

Update:
I've found out that my Hi Spec Billet 4 use a 24mm piston (4 pistons per caliper) so each caliper has a total piston surface area of 1810mm meaning the pair are 3620mm.

The standard ATE caliper uses a single 52mm diameter piston which has a surface area of 2124mm meaning the pair are 4248mm.

ahh it never occured to me the 4 pots would be less (in total) so that makse sense they would need smaller master

[BenH]

Re: GTE valver fast road/track car project

Ben - I didn't think about the sliding effect of the ATE caliper. Keeping this at a high level; A fixed caliper with two pistons at half the diameter of a single piston would offer the same braking efficiency as a single sliding caliper would it not?!?! This would mean that doubling the calculated piston area of a single sliding calipers setup isn't right. I suggest with your pedal box that you go for a .625 for the fronts and .750 for the rear to help balance out the braking to the fronts. You might also consider an in-line bias for the rear to bias even less to them. Might be worth speaking with some motorsport companies to ask what they use as some race cars run huge front calipers and must get round the issue that you had with you large front 4 pots.

Regarding ATE piston diameters the stock 256mm caliper has it stamped on the top of the caliper body 52/24 meaning it's a 52mm piston and a 24mm width disk. The 288mm and 308mm V6 caliper has 56/25 stamped on it meaning it uses a 56mm piston and a 25mm width disk. I believe the early GMF sliding caliper on the 1.8 GTE uses a 48/20 so 48mm piston and 20mm width disk, however the disk diameter was smaller and used a 236mm and not the 256mm as fitted to the later cars. I hope this info helps.

Laurie - I agree with your comments and your 'special' formula as you have said I'm just discussing this at a high level so no requirement to go into huge detail, les keep this very basic.

Yeah thats what I have fitted, .625 front and .75 rear. I'll see how it goes and I always have the .7 as a back up if I dont like the feel of it. As long as I can get it all working and feeling good I'll be happy. I have a bias valve somwhere, I dug it out and put it in a safe place. But that 'safe' place eludes me at the moment, I did put a break in the rear line to unscrew and fit it. If it's needed and can be found. Nice to meet you and Paul today as well

ahh it never occured to me the 4 pots would be less (in total) so that makse sense they would need smaller master

That and the fronts need a higher pressure compaired to the rears. There are so many other things as well that effect the feel, such a caliper efficiency and the leverage ratio. One day I'll get it right lol!

[DarrenH]

Re: GTE valver fast road/track car project

i assume this is also in isolation from any effort reducing valves to the rear, i.e there arent any ? (other than balance bar or aftermarket adjustable valve ?)

[Harvey]

Re: GTE valver fast road/track car project

As some may know the tiny 40amp SBD alternator I purchase the other year decided it didn’t want to output anything over 12v when the engine was running, not good when you need your battery charging. So out came my old faithful GM alternator which has been on since early last year. Luckily for me a mate of a mate was able to test the SBD alternator for me a few months ago and it was the stator and rotor that were deemed suspect. After realising SBD would want to charge me nearly £200 for a replacement I started researching and found some on eBay for around £100. The SBD alternator is actually a Nippon Denso unit exactly the same as this click me. I bided my time and eventually got a cracking deal on two brand new 40amp units but these would need a bit of work, see below. My idea was to keep one of the 40amp units as a spare but I also recently got hold of a slightly larger 45amp alternator. As I plan on fitting Corsa B EPS (Electronic Power Steering) later this year I believe the 45amp unit will be a better option as the EPS will suck the juice a bit more.

Top is the faulty SBD, bottom left is the replacement 40amp and bottom right is the slightly larger 45amp unit.



Pulleys removed with help from my wheel nut impact gun and rubber oil filter wrench holding the pulley. New 40amp unit came with 62mm V pulley where the 45amp came with 70mm V. I use a 55mm 4vee.



Now the fun begins…

This is the rear of both 40amp units, as you can see the replacement alternator on the left has its battery terminal pointing upwards which would actually foul on my inlet manifold. This meant I had to spin the stator 90 degrees so the battery terminal would be the same as the SBD alternator on the right.



I started by removing the rear cover and the brushes.





Then the voltage regulators were removed.





The replacement alternator uses a voltage regulator that I thought used an Econoseal three pin plug but after purchasing one it was too small. After more reading I’ve found it’s a specific plug fitted to some Toyota’s and Japanese manufactured engines that use the Nippon Denso alternators. As yet I’ve not been able to source one but I’m working on it. New regulator on the left (brown) old regulator which uses a T plug on the right (black). Only two connections are required for the alternator to work on my GTE even though the new regulator has three. The extra pin on the new regulator is a permanent live sense wire which is not required. You only need an ignition live and the battery light connecting.



Next up was to remove the rectifiers, these convert AC to DC. If you’re interested in reading up how alternators work http://en.wikipedia.org/wiki/Alternator]click here[/url].

[Harvey]

Re: GTE valver fast road/track car project

Then it was time to split the alternator case and remove the rotors.



Rotors removed.



I was now left with the stator to remove which are an interference fit. As the SBD alternator had a suspect stator I used it as a test removal before I went onto the new alternator.



Suspect stator removed.



It was now time to remove the new stator so I could spin it 90 degrees. Earlier this week I had purchased a set of pin punches so I used the 2.4mm punch and gently worked my around the body of the stator to gently ‘push’ it out. It took about 10 minutes to remove being careful not to damage or touch the windings.







Before removal I had marked the outer stator body with a pencil, this meant I knew how far it needed to go back in and that I had it fitted correctly.





Once the stator was in I refitted everything and used my original T connector regulator before attaching the 4vee pulley.





Replacement alternator now with the battery terminal pointing upwards which is were I need it to be to fit it to the GTE.



I just need to wait for a warmer day without snow so I can fit it on the GTE and confirm it’s pumping out the correct voltage to charge the battery when the engine is running.

[BenH]

Re: GTE valver fast road/track car project

Looks good, did you fit a new brush pack? I always find the new ones take a good few minutes to bed in before giving out the correct voltage.

[DarrenH]

Re: GTE valver fast road/track car project

scary amount of intricate parts all over the place! and good work all round.

the denso alt looks allot like one in the celica.

there are companys that will refurb your old alternator, did you look down that route ?

[Harvey]

Re: GTE valver fast road/track car project

did you fit a new brush pack? I always find the new ones take a good few minutes to bed in before giving out the correct voltage.

Yes, brand new brushes fitted and thanks for the advice.

the denso alt looks allot like one in the celica.

there are companys that will refurb your old alternator, did you look down that route ?

The Nippon Denso alternators come as OE parts on a lot of the Jap stuff as well as compact tractors and plant engines! It was cheaper for me so source my own alternator then to get the faulty unit refurbed. I paid a fraction more for two brand new 40amp units than it would of been to get mine fixed. Now I know they are so easy to strip I'm going to look round for a replacement stator and rotor so I can get the SBD item refurbed myself and keep as a spare.

[Harvey]

Re: GTE valver fast road/track car project

As it was dry and surprisingly mild and warm this evening I popped my head torch on and cracked on swapping over the GTE alternators. It was too late to start the car and check the charging voltage so I’ll do that tomorrow when I get in from work.

OE alternator prior to removal



Big lad and ikle baby alternator



Tiny but mighty Nippon Denso 40amp fitted

[BlackBox]

Re: GTE valver fast road/track car project

I like !!

Where did you get it from and that rose link? Is one thread left handed?

[BlackBox]

Re: GTE valver fast road/track car project

Ebay ... where else lol ...

[Harvey]

Re: GTE valver fast road/track car project

The fitting kit came direct from SBD around 2 years ago and yes the rose joint has one left and one right hand thread. You could buid your own kit quite easily but I just needed it at the time so purchased it complete. Once I've tested that it's charging OK this afternoon it's project Corsa B EPS so watch this space over the next few months...