Plus 2 front brakes on a 2 seater

PostPost by: mikealdren » Thu Dec 10, 2009 1:54 pm

I'm intrigued by what benefits people are expecting here.

As a +2 owner, I'm not clear from the thread whether the disks are changed as well.

I would expect that the increased pad area could provide better fade performance, especially if combined with larger disks. Do road going Elan's need better fade performance? Pad wear may be less to but so what. Not sure what else people are expecting.

Obvious downsides are greater pedal pressures required (or more servo or greater pedal travel) and this also increases the loads on the pedal box components. Greater weight and, more importantly, unsprung weight with obvious ride and handling penalties.

If the +2 calipers were a better oevrall solution I suspect that Chapman would have used them. They were after all readliy available and the cost difference would have been small, even for such a notorious pennypincher.

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PostPost by: GrUmPyBoDgEr » Thu Dec 10, 2009 2:25 pm

mikealdren wrote:I'm intrigued by what benefits people are expecting here.

As a +2 owner, I'm not clear from the thread whether the disks are changed as well.

I would expect that the increased pad area could provide better fade performance, especially if combined with larger disks. Do road going Elan's need better fade performance? Pad wear may be less to but so what. Not sure what else people are expecting.

Obvious downsides are greater pedal pressures required (or more servo or greater pedal travel) and this also increases the loads on the pedal box components. Greater weight and, more importantly, unsprung weight with obvious ride and handling penalties.

If the +2 calipers were a better oevrall solution I suspect that Chapman would have used them. They were after all readliy available and the cost difference would have been small, even for such a notorious pennypincher.

Mike


Mike,

after rebuilding my S4SE without the Servo I found that the Pedal effort was too great for my peace of Mind.
A change to some very expensive Pads didn't provide the result I was hoping for.
I decided to go the +2 route rather than the 4 Pot Caliper route thinking that it would be the cheaper alternative.
In fact new bigger +2 Disks, Pads, sourcing Calipers + Mounting Brackets & getting the Calipers refurbed left not much over compared to a new 4 Pot set up.
The +2 Disks do have a larger Dia. & the Pads cover a larger area.
On my Car the +2 system took a long while to "Bed in" & was initially disappointing.
In my case the point of the exercise was to attempt to achieve Pedal effort somewhere in the region of my everyday Car; something which I have, to date failed in achieving.
My Car is not used in any form of Competition so any Brake fade has not been noticed & the Brakes definitely stop the Car well.
I just wish that I could obtain the Braking ability that I have achieved with less Pedal effort.
Longer Pedal travel would not be unwelcome if it was an aid to Braking progression.
As mentioned before, I realise that reinstating the Servo would provide the solution but I'm not prepared to put up with the associated troubles that are so often written about on the Forum.
I've not noticed any "Unsprung weight" increase penalties on my Car but maybe I'm not driving fast enough.
Nevertheless , although it may in my case be difficult to believe, I am a strong believer in the Lotus keep it light Policy & a pair of nice light Alloy 4 Pots are on the Shelf awaiting fitment :D

I understand that a change from Elan to +2 front Brakes is frequently done by people who compete with their Elans although the legality of the change may be questionable.
Probably not checked or overlooked by Scrutineers?

I also believe that Girling AR & NR Alloy Calipers are acceptable in Competition on 26R's?
Maybe S1's & 2's also? Anyone?
Ooops another Debate possibly :roll:

Cheers
John
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PostPost by: stuartgb100 » Thu Dec 10, 2009 3:48 pm

Hi,

This article and video from AP Racing might be pertinent ..........

http://www.essexparts.com/learning-cent ... ost/Bed-in

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PostPost by: bcmc33 » Thu Dec 10, 2009 7:04 pm

Seeing that video content was a great reminder of the good old Cooper "S" days when we used that method of bedding-in the pads. If you didn't do it correctly, the disc brakes performed worse than drum brakes. And as a matter of interest, the disc brakes were supplied by AP.

I coudn't see any indication of how old the video was - but I was surprised to see ground discs; and by a method that was considered to be the very worst grinding process in operation during the 60's and early 70's.
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PostPost by: bast0n » Thu Dec 10, 2009 10:04 pm

I realise that reinstating the Servo would provide the solution but I'm not prepared to put up with the associated troubles that are so often written about on the Forum.


It just ain't true. The standard setup, properly maintained and used regularily is just sensational and reliable.

Don't believe all that you read..........................politicians and pundits are similar beasts :)
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PostPost by: collins_dan » Thu Dec 10, 2009 10:15 pm

I think I know the answer to this question, but I'll ask anyway: Did all S4's come with servo's? My federal '70 S4 SE doesn't have one and I'm just wondering if it every did. Seems to stop just fine without it. Just curious. Dan
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PostPost by: GrUmPyBoDgEr » Fri Dec 11, 2009 7:14 am

bast0n wrote:
I realise that reinstating the Servo would provide the solution but I'm not prepared to put up with the associated troubles that are so often written about on the Forum.


It just ain't true. The standard setup, properly maintained and used regularily is just sensational and reliable.

Don't believe all that you read..........................politicians and pundits are similar beasts :)


OK you're right to stand up for what you & possibly the majority of "Servo'd" Elan owners consider a good & trouble free Braking System.
Maybe I read too much into the various Posts on here (have a look through the Archives); after all Members usually only Post something when they have a problem & it's not so common for People to Post when everything's working well.
So as you infer, we all are capable of being influenced by Propaganda.
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PostPost by: GrUmPyBoDgEr » Fri Dec 11, 2009 7:18 am

collins_dan wrote:I think I know the answer to this question, but I'll ask anyway: Did all S4's come with servo's? My federal '70 S4 SE doesn't have one and I'm just wondering if it every did. Seems to stop just fine without it. Just curious. Dan


My understanding is that SE's had a Servo as part of the SE extras Package so it should have had one.
But it's an Elan & as we've been reminded of many times there were no hard & fast rules & Customers could alter the Specification when ordering.
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PostPost by: mikealdren » Fri Dec 11, 2009 9:42 am

The article on brake bedding takes me back to two years spent at Millbrook working on brake testing. We used to bed in brakes before any testing but it was always more critical on drum systems than disks and more critical on large commercial vehicles with much greater contact areas.

New pads used to be a bit 'fluffy' and they improved with bedding. Also, until bedded in, the pads may have a smaller contact are and be more prone to fade and subsequent damage to the pads.

Still curious about what benefits people have actually found from +2 brakes on an Elan. Another potential negative I didn't mention was the change in brake balance front to rear.

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PostPost by: GrUmPyBoDgEr » Fri Dec 11, 2009 10:02 am

From what I've read the Racers using the "Standard" Elan Braking system reduce the contact area of the rear Pads in order to achieve the required Front to Rear balance.
Taking this from another angle maybe the +2 Fronts "re-adjust" or even maybe over compensate the balance?.
On the Road I've not encountered any balance problems with my Car's +2 front Brakes.

I've not yet had the chance to watch the "Bedding in Video" but to my shame must admit that the "brutish" method described is the very opposite to what I've always been lead to understand.
Gentle braking for the first few 100 Miles was the recommendation.
My initial thoughts were that the described method was maybe for Asbestos free compounds but the Guys on here who were working in the Industry some years ago have also written that they practiced the hit 'em hard method as being the right way to do it.
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PostPost by: mikealdren » Fri Dec 11, 2009 4:16 pm

John,
We used to use regular but frequent but gentle use to bed in brakes. We were more interetsed in the pads than the disks, once they had an even contact over the whole pad area and had an even 'polished' appearance they were ready for testing.

In my view, the important point is not to overheat the brakes and 'cook' the pads as this irrevocably damages them. On the materials I used to test, the binders in the pad material burned out. However, to inflict this sort of damage you need to get them very hot, if they start to smell, you may be going too far so back off. We used to monitor the disk temperatures with rubbing thermocouples, ancient technology now!

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PostPost by: GrUmPyBoDgEr » Fri Dec 11, 2009 5:42 pm

mikealdren wrote:John,
We used to use regular but frequent but gentle use to bed in brakes. We were more interetsed in the pads than the disks, once they had an even contact over the whole pad area and had an even 'polished' appearance they were ready for testing.

In my view, the important point is not to overheat the brakes and 'cook' the pads as this irrevocably damages them. On the materials I used to test, the binders in the pad material burned out. However, to inflict this sort of damage you need to get them very hot, if they start to smell, you may be going too far so back off. We used to monitor the disk temperatures with rubbing thermocouples, ancient technology now!

Mike


Yes Mike, your first Sentence describes the way I was told to do it & is also mentioned in Car users Manuals.
Sorry for misunderstanding your earlier posting.
John
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PostPost by: Yum-yum » Fri Dec 11, 2009 6:58 pm

Just as another data point, my early S4 SE Federal does not have a servo and I don't believe it ever did. I've always had phenomenal braking and the only problems have been from not periodically changing the brake fluid.
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PostPost by: bcmc33 » Fri Dec 11, 2009 7:32 pm

As a matter of interest - what is the pad area for the Elan and +2?
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PostPost by: bast0n » Sat Dec 12, 2009 5:10 pm

Dan

You asked about the aly bubble wrap. Available from Demon Tweeks at demon-tweeks.co.uk and is called Cirrus heat shield. I enclose a couple of pictures so you get the general idea. Note the anti rust treatment provided by the engine...............!
Attachments
jsf_IMG_0025.jpg and
jsf_IMG_0034.jpg and
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