Braking bias

[MetalSpikeRacing]

He he he :redface: , my bad.
Most of been Sauber's bad qualifying that got me on edge.

Nothing to see here folks , move along. :tongue:

-MSR

 

[han0355]

I understand, a friend of mine just bought a set of 235/40/17 front and 275/35/18 of z1 star and I took it out for a test drive, I can feel the grip is MUCH better than my 235 Falken even on normal driving.

I bought a set of second hand (barely used) NT555's off from a friend's hand with just 300 bucks, so gonna see how it performs, will still switch to z1 star if end up not liking it.

Also bought a set of comptech pro last week, thinking whether if i should install it right now or later till track season, probably gonna go with NT01 or A048, what kind of settings would you do?

Really appreciate your opinion, thanks alot!

Here is part of your problem, Falken tires are known to be thin walled by running falkens 235 at the front (wich are more like 215's ) you are not getting enough grip.

I was running 275 star specs at the rear and 215 falkens rt-615's at the front, 215 rt-615 's are more like 195's on a real tire size.
Because of this, I was having masive understeer but more than anything I was looking up the front big time.

I have ever since switch the fronts to star specs 235's and the locking and understeer its gone, like magic...


Falkens are the thinest tires out there and direzzas star specs have to be the thickest, they are pretty thick.


-MSR

 

[han0355]

Thanks for the advice! I'll look up and do some more research with tires, I believe thats what causing me massive understeer and front tires locking up.

My reference toward you wasn't a bash or a discredit so no worries.

 

[MetalSpikeRacing]

Comptech pro, I am assuming coilovers?
Would be cool for you to wait to track season before you put them on, then do a track day in stock suspension and then put them on.
That way you will really feel the improvement , just a though.

Like I say, it'll be cool. Sucks because I didn't do it my self.

-MSR

I understand, a friend of mine just bought a set of 235/40/17 front and 275/35/18 of z1 star and I took it out for a test drive, I can feel the grip is MUCH better than my 235 Falken even on normal driving.

I bought a set of second hand (barely used) NT555's off from a friend's hand with just 300 bucks, so gonna see how it performs, will still switch to z1 star if end up not liking it.

Also bought a set of comptech pro last week, thinking whether if i should install it right now or later till track season, probably gonna go with NT01 or A048, what kind of settings would you do?

Really appreciate your opinion, thanks alot!

 

[CB72]

I've read through this thread very quickly and believe that changing the tires around will hide the bias issue somewhat but will not cure it....
Don't forget that if the track conditions change, like if it rains the bias problem is going to resurface badly.
I personally have spent more time tuning the brakes on my NSX than the engine (CTSC first then Love fab turbo).
I started off like you with a BBK upfront ( Porsche 993 turbo calipers on 322*32 disks) and discovered how horrible it was when you change the original NSX brake bias of 60%.
In the end I devised my own rear BBK by using AP Racing CP 7611 four pot calipers working on NA2 rear disks.
This gave me the ideal 60% ratio and I can garantee that no Porsche will outbrake me on the track.
If you have Stoptechs upfront, buy their rear brakes and skip the handbrake until you have more cash.
BTW Dali has a table that shows the different biases you will get with all the brake combinations you can imagine.
I personally never had an issue ordering from M.Johnson over the last ten years...

 

[GhettoRacer]

I'm chiming in here because there's some REAL legit threads on tires from people with tons of experience at the track and since you're tracking your car and not pretending to track it, I recommend you read some of the threads from the past.

Anything that Nsxtasy posts about tires is legit. Not say others aren't "metalspikeracing I know you're a tracker", but read some of Nsxtasy's posts on tires here on prime.

I beg to differ. NSXtasy is not always right about wheel and tire combinations...

 

[GhettoRacer]

I've read through this thread very quickly and believe that changing the tires around will hide the bias issue somewhat but will not cure it....
Don't forget that if the track conditions change, like if it rains the bias problem is going to resurface badly.
I personally have spent more time tuning the brakes on my NSX than the engine (CTSC first then Love fab turbo).
I started off like you with a BBK upfront ( Porsche 993 turbo calipers on 322*32 disks) and discovered how horrible it was when you change the original NSX brake bias of 60%.
In the end I devised my own rear BBK by using AP Racing CP 7611 four pot calipers working on NA2 rear disks.
This gave me the ideal 60% ratio and I can garantee that no Porsche will outbrake me on the track.
If you have Stoptechs upfront, buy their rear brakes and skip the handbrake until you have more cash.
BTW Dali has a table that shows the different biases you will get with all the brake combinations you can imagine.
I personally never had an issue ordering from M.Johnson over the last ten years...

More information about the AP CP7612 setup with NA2 rear disc... custom mounting hardware?!?! Please show me some photos. Our 91 NA1 rungs Dali (Brembo) front brakes, and stock NA1 rear brakes. We also have the same biasing and lock up issues that the OP described!!! Our car used to run all factory brakes, except with the old school RM Racing track pads (I'm not sure who's pad compound it was), but I swear the braking performance with that pad was MUCH BETTER than what we currently have...

Wow, Mark has the answer for us!! http://www.daliracing.com/v666-5/catalog/index_browse_part.cfm?focus=548

 

[GhettoRacer]

Han -
Since you're new here and some member choose to just link to a vendor without any input, I advise you to PLEASE research DALI before you purchase. A LOT of people have had issues on never receiving parts and loosing money. So, I caution you to please choose who/where you purchase through carefully. DALI has a mixed reputation. I personally have never purchased, but I've read enough negative feedback where I never will.

Hope that helps.

I'm referring to this post:

We have bought from Mark @ Dali for over 10 years with out problems. He has better pricing than pretty much all other NSX vendor and plus his web site is just awesome. We've grown to appreciate him more and more. Good dude.

 

[CB72]

More information about the AP CP7612 setup with NA2 rear disc... custom mounting hardware?!?! Please show me some photos. Our 91 NA1 rungs Dali (Brembo) front brakes, and stock NA1 rear brakes. We also have the same biasing and lock up issues that the OP described!!! Our car used to run all factory brakes, except with the old school RM Racing track pads (I'm not sure who's pad compound it was), but I swear the braking performance with that pad was MUCH BETTER than what we currently have...

Wow, Mark has the answer for us!! http://www.daliracing.com/v666-5/catalog/index_browse_part.cfm?focus=548

I did this modification quite some time ago and I'll try to find some pictures for you.
What's interesting with the CP 7611-S05 R2 caliper is that it's intended for a lateral mount ( versus radial).
The two mountings lugs are too long for the NSX so it's only a question of shortening them and and redrilling the two M12 mountings.
Laterally, I had to shave 1.1 mm off the lugs to get the offset right.
I searched the AP Racing site and could only find the calipers as part of a BBK for the Mini.
You will note that the recommended disk size is 304*24 :smile:
I believe these calipers ( check the piston diameters !) was OEM equipment for the front on the latest small MG 2 seater....

http://www.apracing.com/info/produc...ductpics/BMW_MINI_Cooper_S_1.jpg"/>_2749_2718
Here are some recent pictures I took while converting the body to 2002 + version.