Is there a way to reduce servo assistance? - Mitsubishi Lancer Register Forum
 
 

Go Back   Mitsubishi Lancer Register Forum > Technical > Brakes

Reply
 
Thread Tools Rate Thread Display Modes
Old 17-05-2019, 08:54   #1
plip1953
Phil
 
plip1953's Avatar
 
Join Date: Feb 2008
Location: West Yorkshire
Car: Evo X 300 SST
My Car
Posts: 10,422
Is there a way to reduce servo assistance?

This is a general rather than Evo specific question.

Is there any relatively simple way to reliably reduce the assistance provided by an existing servo, or it is all or nothing?
__________________
Phil
plip1953 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 17-05-2019, 14:46   #2
super rover
acting daft since 1969
 
super rover's Avatar
 
Join Date: Oct 2006
Location: PRESTON ,lancashire
Car: E7 RS RALLY CAR
My Car
Posts: 19,230
i very much dought you can ,we alter the pivot point on the pedal on rally cars to help as we run servoless ,not sure it would work going the other way
__________________
MY RALLY CARS FOR SALE

<<<<<<<<< THIS

HERE >>>> https://www.lancerregister.com/showthread.php?t=579947
super rover is offline   Reply With Quote
The Following User Says Thank You to super rover For This Useful Post:
plip1953 (17-05-2019)
Old 17-05-2019, 23:36   #3
kikiturbo
Senior User
 
Join Date: Feb 2008
Location: Croatia
Car: EVO 9 GSR
My Car
Posts: 2,550
you can always change the master cylinder for a larger one (to decrease the brake force)
kikiturbo is offline   Reply With Quote
The Following User Says Thank You to kikiturbo For This Useful Post:
plip1953 (18-05-2019)
Sponsored Links
Advertisement
 
Old 18-05-2019, 07:50   #4
plip1953
Phil
 
plip1953's Avatar
 
Join Date: Feb 2008
Location: West Yorkshire
Car: Evo X 300 SST
My Car
Posts: 10,422
Quote:
Originally Posted by kikiturbo View Post
you can always change the master cylinder for a larger one (to decrease the brake force)
We're currently running the car with the servo disconnected and that is kind of working especially insofar as it pretty much eliminates locking up, but given how hard the pedal needs to be pressed it makes modulation so much harder and also makes it harder to heel and toe on downshifts.

Changing to a bigger bore master cylinder is clearly an option (as is converting to a pedal box arrangement), but I was wondering if we could retain the current arrangement, but simply reduce the amount of servo assistance. I've even considered whether switching to a hydraulic assistance system might work as I imagine it would be relatively simple to regulate the amount of pressure that forms into the assistance?
__________________
Phil

Last edited by plip1953; 18-05-2019 at 07:59..
plip1953 is offline   Reply With Quote
Old 18-05-2019, 15:32   #5
evo7_GERMANY
User
 
Join Date: Apr 2004
Posts: 54
Servo assist is judged by the diameter of the Servo aka Break Booster.

Evo has eighter an 8 or 9 inch one, to half the assist you will need an 6 or 6.5 inch one. Since man JDM Cars using the same style of booters / Master cylinders, it may be possible to find one in an scrap yard....
__________________
EVO7 and EVO9 Wagon
One for FUN, one for Fast Transportation
evo7_GERMANY is offline   Reply With Quote
The Following 2 Users Say Thank You to evo7_GERMANY For This Useful Post:
kikiturbo (19-05-2019), plip1953 (18-05-2019)
Old 19-05-2019, 19:17   #6
super rover
acting daft since 1969
 
super rover's Avatar
 
Join Date: Oct 2006
Location: PRESTON ,lancashire
Car: E7 RS RALLY CAR
My Car
Posts: 19,230
we run our cars servoless ,we alter the pivot point on the pedal for the master clyinder to help with pedal pushing effort ,and it does work
__________________
MY RALLY CARS FOR SALE

<<<<<<<<< THIS

HERE >>>> https://www.lancerregister.com/showthread.php?t=579947
super rover is offline   Reply With Quote
Old 19-05-2019, 19:19   #7
kikiturbo
Senior User
 
Join Date: Feb 2008
Location: Croatia
Car: EVO 9 GSR
My Car
Posts: 2,550
Quote:
Originally Posted by super rover View Post
we run our cars servoless ,we alter the pivot point on the pedal for the master clyinder to help with pedal pushing effort ,and it does work
you run OE brembos?

I tried the big Brembo grN setup and that works ok without the servo... hell I even bought one...
kikiturbo is offline   Reply With Quote
Old 19-05-2019, 19:39   #8
super rover
acting daft since 1969
 
super rover's Avatar
 
Join Date: Oct 2006
Location: PRESTON ,lancashire
Car: E7 RS RALLY CAR
My Car
Posts: 19,230
weve run both set ups reds and VOs ,works well either way
__________________
MY RALLY CARS FOR SALE

<<<<<<<<< THIS

HERE >>>> https://www.lancerregister.com/showthread.php?t=579947
super rover is offline   Reply With Quote
Old 20-05-2019, 02:21   #9
Unobtainium
Registered User
 
Unobtainium's Avatar
 
Join Date: Aug 2005
My Car
Posts: 36,162
Quote:
Originally Posted by plip1953 View Post
This is a general rather than Evo specific question.

Is there any relatively simple way to reliably reduce the assistance provided by an existing servo, or it is all or nothing?
Or to be perfectly specific...this question is about the braking problems you have on your MX5.

Are most of the MX5 racecars having this problem too or is it just yours?

Have you seen the brake setups you can buy that look like the standard pedals only with a proper pedal box style brake bias setup? Omega run one on their Evo.
__________________
My latest thread: Kenny1's Evo 5 RS - Throughout the years

Last edited by Unobtainium; 20-05-2019 at 02:24..
Unobtainium is offline   Reply With Quote
Old 20-05-2019, 07:32   #10
plip1953
Phil
 
plip1953's Avatar
 
Join Date: Feb 2008
Location: West Yorkshire
Car: Evo X 300 SST
My Car
Posts: 10,422
Quote:
Originally Posted by Unobtainium View Post
Or to be perfectly specific...this question is about the braking problems you have on your MX5.

Are most of the MX5 racecars having this problem too or is it just yours?

Have you seen the brake setups you can buy that look like the standard pedals only with a proper pedal box style brake bias setup? Omega run one on their Evo.
The issue has been "resolved" to the extent that the servo is now disconnected. However, I would ideally like to find a way to provide the option of variable assistance to suit different track conditions (ie wet or dry) and choice of tyres (1Bs or slicks).

We are not aware of other MX5 owners having the same kind of issue with front lockup.

If at all possible we'd like to keep the current pedal arrangement (the pedal positions and spacing is currently very good).

Can anyone tell me if the design of servo units is essentially the same across a broad cross section of make and models? In particular, is the spacing of the servo to bulkhead bolts completely variable or is there a recognised industry spacing standard (ie a bit like wheel nut spacing arrangements albeit that there a number of them)? If it is, then maybe I can find a smaller diameter servo that would slot straight in? And I wonder if rod arrangements between the pedal and MC are to a general standard or different in every case? Please bear in mind that I've yet to even take any servo or MC off any car so please feel free to tell me I'm way off in any of my thinking or line of questioning.

Another thought is whether installing a regular type of brake proportioning valve in the front brake lines might work ie to control the effectiveness of the front brakes? The driver style preference in this instance it to be able to initially stamp on the brakes and modulate thereafter. Right now, with no servo, the "stamping" requirement is totally achieved, but at the expense of the amount of overall effort required and also partially at the expense of modulation and ease of trail braking. Heel and toeing is also made harder.
__________________
Phil
plip1953 is offline   Reply With Quote
Old 20-05-2019, 10:26   #11
thetyrant
Senior User
 
Join Date: Oct 2002
Location: Cumbria....
Car: BMW 130i & ST185 GT4 RC - Previously: Evo9-FQ360, Evo5-RS + 2 x Evo2's, all gone but not forgotten.
My Car
Posts: 16,792
Fitting a servo delete plate will improve things over current setup (just vac line disconnected) much like some of the Evo rally guys do, also then you could play around with master cylinder sizing but it may not be needed once resistance of servo unit is removed from the setup.

Ive not been able to find one for your NC MX5 but below link is for earlier car and also the Arnside one for Evos for reference, should be easy enough to make one up to play with, get the hacksaw and drill out

Arnside Evo - https://www.arnsidemotorsport.co.uk/...t.php/6618291/

MX5- https://fab9tuning.com/fab9tuning-br...lete-tuck-kit/
thetyrant is offline   Reply With Quote
The Following User Says Thank You to thetyrant For This Useful Post:
plip1953 (20-05-2019)
Old 20-05-2019, 13:41   #12
kikiturbo
Senior User
 
Join Date: Feb 2008
Location: Croatia
Car: EVO 9 GSR
My Car
Posts: 2,550
Quote:
Originally Posted by plip1953 View Post
Another thought is whether installing a regular type of brake proportioning valve in the front brake lines might work ie to control the effectiveness of the front brakes? The driver style preference in this instance it to be able to initially stamp on the brakes and modulate thereafter. Right now, with no servo, the "stamping" requirement is totally achieved, but at the expense of the amount of overall effort required and also partially at the expense of modulation and ease of trail braking. Heel and toeing is also made harder.
what do you use for brake ballance now?
kikiturbo is offline   Reply With Quote
Old 20-05-2019, 14:32   #13
plip1953
Phil
 
plip1953's Avatar
 
Join Date: Feb 2008
Location: West Yorkshire
Car: Evo X 300 SST
My Car
Posts: 10,422
Quote:
Originally Posted by kikiturbo View Post
what do you use for brake ballance now?
A Tilton proportioning valve in the c0ckpit acting on the rears brake line.

I'm currently considering this. It permits retention of the current pedal arrangement, but supposedly with an adapter to provide a higher pedal ratio. And there's also the ability to play around with different diameter AP master cylinders.

That said, I've heard from a couple of source that the build quality of the Compbrake stuff is questionable!

https://www.compbrake.com/product/ma...ylinder-kit-a/
__________________
Phil

Last edited by plip1953; 20-05-2019 at 15:04..
plip1953 is offline   Reply With Quote
Mitsubishi Lancer Register
Sponsored Links
Advertisement
 
Reply


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
6 pot caliper:pedal effort/loockin in evo 5/6 original brake pump servo system no abs erwing Brakes 17 01-11-2014 13:48
Brake servo delete 4 to 9 Evo solutions billet alloy liddy Private Sales - Parts 5 07-11-2013 02:04
Hissing noise behind dashboard. Air leak? Servo? noisymini Technical Questions 4 16-06-2013 20:27
Ferrari International Assistance (FiA) CHUBBS Non-Lancer Chat 13 11-09-2008 12:17
Brakes: Servo assistance and anti-lag/jacked throttle geefin Technical Questions 2 09-01-2008 11:28



All times are GMT. The time now is 11:47.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.