Adelberg - out of line

[Gavin]

I have had multiple emails with Ken regarding his problem. In those emails I requested technical data supporting his claim - He responded with his opinions and a lot of complaint about what Sean would not do.
I made a concerted effort to get Ken to even consider looking at the problem from another angle - to consider that he may have a problem with something else on his car. He ignored every point I made.Now lets get this straight - I don't think Ken is a bad guy - I don't agree with his post - I think is is not being as open minded as he could be on the issue.

Now I run Sean's setup on my 1996 GTS and have also have run two full days at Laguna Seca and have not experienced any problem such as Ken experienced.
I did not install the system myself - Sean recommended a professional do the work.

Based on information obtained from Ken I believe he had a pre-existing "line Pressure" problem. All I have to guide me to this conclusion is my own assesment of what could cause an event such as Kens. In other words, something in the stock system is causing line pressure and resulting in the brakes being applied slightly. When the brakes should be at restandcooling they are not,due to the line pressure. They simply continue to heat up.

Ken admitted to Sean that he saw evidence of this line pressure when he pulled the system apart - I questioned Ken about this and he avoided the question.

So, instead of all these accusation, how about some real technical data - I'm sure a few of you Viper owners that have solid understandings of how braking systems work could come up with one or two theorys to why Kens brakes stayed in the "applied mode".
There are only two scenarios that I can see - either something was causing the pads to be applied to the surface of the rotor or something caused the rotor to expand beyond their designed tolerences, literally reaching out and touching the pads.
First scenerio I know what can cause that - the second is surely beyond my understanding.

So what are your thoughts guys and girls - what could cause Kens failure??

 

[GTS Dean]

Now this is a good, informative discourse on the subject.

Apparently, something is causing the proportioning valve or the master cylinder to act as a residual pressure valve in the rear circuit of Kenny's car. Brake lines have a very small I.D. and it doesn't take a very large foreign object to cause an operational problem in the system.

 

[JonB]

"Don't Mess With The Old Family Recipe" has a bearing here.

As old-timer like dean know, we monkeyed with brake bias by modifying the OEm prop valve and master Cyl....and we experimented w/ Wilwood (and Tilton?) adjustable prop valves.

"Adjust youyrself right off the track!" is another comment.

1) HEAT may be playing a role here. Is the Willwood valve being overheated by (stainless?) headers, due to its placement? Is it insulated in any way? I insulate my lines and M/C....and P/B booster as well. HEADER HEAT adversely affects these components.

2) Is Ken a FASTER driver than Gavin? Lots faster? Racing at 80% of vehicle capacity is light-years away from racing at 101%. I hear that Ken is a 102-102% driver. If so, his brake system had better be MUCH BETTER than an 80% or 90% driver.....

 

[luc]

I was at Laguna Secca when Ken locked the rear wheels coming out of turn 3.
After waiting for the race to end and in the same time to give a chance to his brake system to cool,he was able,with the rear brake draging,to drive to the paddock.
I remember clearly that when we opened the bleeder valve,the brake fluid was under pressure.
Ken told me that the rear set-up was a front Corvette system adapted to fit at the rear of the viper.

May be Ken is not the best mechanic but he is not stupid and he his a VERY good driver as well that a pretty nice guy.

As a SCCA racer and viper owner,I do have some ideas/comments regarding this brake problem.
What create heat is friction,and obviously, the pads are still making contact with the rotors,even when the brake pedal is not applied.
There are only 2 possibilities,either a mechanical one as in the calipers pistons not releasing/draging due to a bad O ring.
The only thing that make a piston retract is the O ring acting as a rubber band.
Under braking the OD of the O ring is locked in place by the groove in the caliper and the ID move out with the piston/puck.
When you release the brake,the O ring return to it's original shape and pull the piston back.
or a hydraulic,brake fluid problem.

Let's look at the mechanical side first.
There are 2 reasons for a piston/puck not to move back
Scored,damaged/rusty pistons.
Not likely on a "new" system.
O ring.
It is possible but very rare that the O ring is of the wrong size/material and simply doesn't have enough "memory" and/or frictional contact with the OD of the piston to retract it.

I seems to remember that those caliper are 4 pistons calipers,but even 1 sticking piston will create this problem.
Also it seems possible that with a locking/limited rear end,if 1 side is locking up that the other side will.
I know that on a spool or Detroit locker it will but I am not sure what Ken run on his car.

Hydraulic/brake fluid.
Obviously the brake fluid was under pressure when we opened the bleeder valve.
on the Viper,being a vertically split sytem you are really dealing with 2 separate hydraulic systems.
one for the front brake,controlled by the primary port on the master cylinder and the rear by the secondary port on the MC.

Gilbert Racing describe a problem where some junk in the bias valve was creating residual pressure,(like in a front discs/rear drums system)and slowing but not locking the rear wheels.

My guess is that it is not the problem on Ken car because while I agree that junk can create restriction,therefore residual pressure,it is usually not "air tight".

I will tend to think that the problem is in the proportionning valve that doesn't let the brake fluid go back from the rear line.
As the brake fluid heat up,the locking become worst due to the fluid expending and having only 1 way to do it,moving the calipers pistons out.
If it was my car,I will keep the brake system on but beside reverse flushing it,I will change all the O rings and the pressure differential/proportionning valve.

Luc.

 

[Janni]

Boy I feel pretty smart! This is about what I had guessed on the other thread... Thanks for more info... I am eager to see a resolution.

 

[Jon 98GTS]

Gavin,

When there are flames coming out your rear wheels because a brake system failure caused a fire, how much more "technical data" do you need that there is a problem?

Ken's not an engineer nor does he pretend to be one. He probably thinks that Boyle's Law has something to do with cooking... BUT he does know when to defer to the experts.

The first expert he went to was Sean Roe who told him all kinds of "technical data" and sold him more parts.

When it failed AGAIN, he went to TWO other experts who basically told him to flush the system down the toilet. I'm sure they could have dazzled Ken with "technical data" but why bother? Ken wouldn't completely understand it and if the hole in Ken's checkbook wasn't enough, then the flat spots on his rear tires would probably provide enough convincing data.

Bottom line: They only "technical data" I've heard in support of Sean's system has either come from Sean OR from Gilbert Racing (who has expressed a dislike for Ken in another post).

I betcha Bob Lee would be willing to give you a ton of "technical data" about the problems with Sean's system. Have you talked to him?

Adelberg wasn't "out of line" -- the only thing that is "out of line" is your suggestion that he is.

 

[SoCal Rebell]

Nobody's out of line here, whether the brakes were defective or not it it Kenny's right to post it on this board. This is the basic fundamental reason for this board, to post problems and ask for comments and opinions. It is up to us as individuals to to interpret the info received and respond if so inclned. JUST because he is talking about someone you like you cannot chastize him. This is what freedom of speech is all about.

 

[kverges]

Why the personal attacks in a technical discussion?

In principle, brakes are simple hydraulic systems transmitting the master cylinder piston pressure to the caliper piston.

It sounds as though something is causing residual pressure to be retained in the rear circuit. I highly doubt it is the rear calipers, as I know of no valving in the calipers that would retain pressure; the piston o-rings should in fact retract the pistons slightly when hydraulic pressure goes down to zero.

I would look very carefully upstream of the system to see how there could, in effect, be a "check valve" in the rear brake circuit. First, the proportioning valve (stock or any aftermarket) should be checked and cleaned. Second, the M/C should be checked and cleaned, especially if it or any part of it is non-stock. Also, the M/C is designed to close off the port to the fluid reservoir as brakes are applied, but then allow that port to open when brakes are released. This allows the extra fluid into the brake system to accomodate for piston travel and expanding fluid out and into the reservoir under extreme operation. Is there any chance that the M/C piston travel could be out of range due to adjustment or error on installation? This would explain why the brakes lock up when they get hot, as the expanding fluid has nowhere to go, even when the brakes are released.

Bottom line: I will bet you could put ANY rear caliper on the system and have trouble; I would very carefully inspect all the upstream components, especially aftermarket pieces. The domino effect of any modification can lead to truly surprising and unexpected results.

FWIW, but do let us know the definitive culprit. It will help us all in track prep and diagnosis of any similar problems.

And really, the name-calling does not advance the ball at all.

 

[GTS Dean]

I think that novice drivers will usually get the brakes hotter, faster, with less need to do so. They brake too early and too often, keeping the pads in contact with the rotor longer and transfering more heat to the working fluid. (hydraulic, not air)

Better drivers brake less, but harder. They spend more time OFF the brakes, going faster, but generate just as much - if not more heat - in a shorter amount of "pedal on" time than the novices. The only time the brakes cool is when your foot is off the pedal.

 

[Y2K5SRT]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by PMUM:
Now that it turned out that the brakes are useless, he unpimps his first comments and Moderator Roe decides to pull it. It must be nice!<HR></BLOCKQUOTE>

My Dear Mr. PMUM -

I am pleased to report it was not my wicked scythe that mowed down the mighty post of Ken. Quite honestly, I thought it was an interesting discussion, especially as there were some real nuggets of good technical info buried in there. I believe the rules of the board are that posts like this need to be based on fact. I couldn't debate anything Ken wrote as being blatantly false from what I read. It seemed to jive pretty much with what Sean Roe had posted originally, although the camera angles are decidedly different. While there may be a few posts worth editing in this most recent thread by Ken, I wouldn't mind seeing some of the more factual stuff reappear. I don't have a problem posting a "why" if a thread is closed or moved, but in this case it was not my call...

Chris

P.S. This is my only comment on this subject (moderating). I think we pretty well burned up this candle on the "PG Board" thread last month.

 

[Sean Roe]

This response is only directed to the subject of braking differences between novice and professional drivers.

It is obvious that may of you who weighed in with your opinions, (Jon Brobst, Brett and Paul Mumford) have not been around amatuer and professional motorsports very many years. If you had been, it would be clear to you that novice drivers are typically harder on brakes than experienced professionals.

If you don't believe me, how about the General Manager of a west coast based aftermarket brake company that sells Viper brake systems? Here's what he had to say in regard one of his customers recent brake problems (direct quote from his e-mail) "New and beginning drivers tend to brake more than experienced drivers as you well know."

 

[K Adelberg]

Sean, you make a very interesting point. However, continue to avoid the topic of your brake system. Although Mumford, myself and others who have written here are not professional drivers, we are certainly not new and beginning drivers.

 

[HogWhisperer]

*** The thread this quote came from is closed. Hope it's OK to post here.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by PMUM:
After they figured out the real problem, Ken returned them and did get his money back for the second set of unused, never caught on fire, calipers.
<HR></BLOCKQUOTE>

After they figured out the real problem? So does that mean someone actually knows what the cause of the problem is? I was under the impression that having never diagnosed and verified the problem, Ken bought a complete new setup and then demanded a full refund from Sean.

 

[K Adelberg]

Just to clarify. The root of the failure was not determined, but there were several well drawn conclusions. I returned newly purchased rear calipers from Sean Roe at a "discount" which were purchased because the car was not drivable and I didn't have many other options.

 

[PMUM]

No offense Dion, but an experienced driver waits until the last moment and smoothly gets ALL OVER the brakes, then smoothly eases out as he's going into the corner....all without scaring himself, overbraking or accelerating late. This puts massive amounts of heat into the brakes.

Gavin, just out of curiousity, what kind of times were you running at Laguna? Because Ken's brakes were working well when he was running 1:44s earlier in the day, but when he was running 1:40s later is when the brakes died? Ever been to Laguna with Bontempi? Watch that guy run a couple of laps well into the 1:30s and grab a heat gun and see if your brakes or his are hotter.

 

[JonB]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Sean Roe:
..............It is obvious that may of you who weighed in with your opinions, (Jon Brobst, Brett and Paul Mumford) have not been around amatuer and professional motorsports very many years. If you had been, it would be clear to you that novice drivers are typically harder on brakes than experienced professionals. <HR></BLOCKQUOTE>

Sean Roe, I have never challenged you or your products, opinions, or any other tuner. Just your mis-statement of my posts! And now, you do it AGAIN! In fact, my post way above suggests heat-related Power Steering Booster and Master Cylinder problems, not Sean Roe Under-engineering. Do NOT impune my experience to mask your customer service/under-engineering problems. Since you DID question it, though:

My first autocross (It was called 'Gymkhana' back then)was in a Fiat in 1966. I have been involved with amateur motorsports since 1971. [I took a decade off in Alaska and raced dogs.] I have held SCCA and ICSCC sanctioned racing licenses....and I partcipate in approximately 250+ RACES PER YEAR in some capacity or another. I currently have SCCA licences in Race Control, F+C, Emergency Services; I have an International Pace Car Licence. I have popped fire bottles on brake fires, and seen many an experienced driver in SCCA and even NASCAR with brake fires, unknown to them. I have been a PCA, BMW, Audi, Team Continental, VCA, and Viper Days instructor...and some I forgot.

I stand by my statement: An unknown novice like "Gavin" above driving at 80% or 85% will use far less brakes than a Mumford-Adelberg-Word calibre driver at 101%. For you to make a blanket statement about MY experience, and another (backing your trite savior Ernie) that 'Novices are harder on brakes than experienced drivers' brings into question YOUR understanding of brakes and motorsports. (It must be right up there with your understanding of aerodynamics..) If this were true, pro-drivers would not need bigger brakes than novices.

What Dean Word said is 100% correct. You only told HALF the statement of the "West Coast manufacturer"...[as you seem to do when trying to plead your case and twist other's and my words.]

The facts: SOME clueless novice-intermediate drivers CAN BE harder on brakes than SOME advanced drivers; MOST advanced drivers are much harder on brakes than MOST novices or intermediates. Want proof? The consumables tell the tale: Pads, rotors, seals, even CALIPER PAINT!

 

[PMUM]

There are no headers on Ken's car.

 

[Dion Fisher]

This has little to do with Ken's lock up problem but there is several opposing views on the braking issue.. I for one was much harder on my brakes (used to get them way too hot) and was turning poorer times when I was posting my first few thousand track miles locally..

Since then I have found that I am able to be faster by just keeping my car in balance and not scaring myself half to death trying to slow down from 170+ to enter a 60mph corner while late braking then ending up accelerating late because I used up all the corner trailbraking and trying to stay on the track.. What a waste of time that was..

Not to say that I haven't had reason to go faster and push the limits of the car's modified stock braking system and MXX3s here and there but that usually only happens when i'm playing with somebody's mind that has Brembos and Hoosiers on their car.. But then i'm only a play on the track person an actual race for the money is a whole different environment

 

[Dion Fisher]

Correction accepted,
I guess I should have been more specific as to what I was alluding to.. I really was only refering to my own experience level which is undoubtedly lesser than Paul's -took 1st in- "Unlimited" **BRAVO** Paul, and/or Ken's and many others of you out there.

As I stated earlier "I am just a track play person" advanced level and would be considered a Novice if I was ever to race door to door.. And as I also stated "racing for the money is a whole different environment." Should have stayed out of the convo since i'm an apple in an orange cart..

But since i've opened my mouth; what I meant to say was "in practice" I have just chosen to slow down my straight line speeds ((unless pushing for some reason)) and concentrating on the cornering which has netted me better times on the track.. If I was really trying to compete seriously i'd go for the big brakes, Hoosiers, etc, etc, and etc,.. Oh well, i'll learn to be more specific when dealing with HOT *pun* issues