Brake upgrade question - which calipers to go with?

[Joseph Dell]

I probably should have posted this _before_ I handed my money to JonB, but... I gotta know.

I decided to go with the Stoptech FRONT ONLY brake upgrade. I drag race and will auto cross a _little_, and I need the real braking power on the street. So here are the questions.

1 - I ordered the big front calipers (for 18" tires), yet stoptech claims the ones for the 17" tires stop just the same. I went with the 18" anyway. 355mm, methinks. Was that a bad idea? Or would I have been just as well off with the smaller ones?

2 - If I get the opportunity to install a brake proportioning valve for the rear, should I do so? what exactly does that thing do anyway?

I read all the archives on this topic so I think I am semi-knowledgable, but brakes are something I've never messed with much in the past.

Thanks in advance!

JD

 

[Chuck 98 RT/10]

Since you’re primarily a dragger you could have done well with just an aggressive pad on a stock system and steal braided lines.

Stoptech has always said the 17 stops just as well as the 18. They certainly have more R&D in it than I do, but it never seemed logical to me. However for your app I certainly agree with them. Brakes really don’t get tested until you go into a turns at 140mph lap after lap.

The pv adjust the influence between front and rear. I don’t recommend it in your app because it takes some fiddling to find out how much is too much or too little. To my knowledge few Vipers have them at Viper Days.

 

[FrankBarba]

I have never had Buyer Remorse when purchasing from JonB at Parts Rack. You shouldn't either.

 

[Joseph Dell]

Chuck -

Thanks for the feedback. The 17 vs 18 doesn't make sense to me either. but the pv comment does. Thanks for your help!

I'll never have buyer's remorse from JonB... just figure I should ask for help before I spend $$$.

 

[Jim Hodel]

I've had experience with brake upgrades on a variey to cars including a Z28, a Mitsubishi 3000 GTVR4 and my Viper, although I have tried only the Stoptech 13 inch front system on the Viper (oh, and pads/fluid on the stock system). FWIW, all of the 'big brake' packages were an improvement in track braking. Maybe the single stop street stopping distances weren't improved drastically, but ongoing track performance is better.

Be happy with your Stoptech choice. I still find the braking performance of the Viper to be substandard compared to the other cars with brake upgrades, but it is still improved over stock.

Jim

 

[Tom F&L GoR]

The front only kits utilize smaller pistons than stock, so that the front brake torque is reduced for a given amount of hydraulic pressure. This balances the front-to-rear braking so you don't lock up a front tire, and works the rear brakes more.

Going by the math only (and not accounting for some heat rejection advantages their rotors have) the same can be achieved with going bigger in the rear, to 38mm from 36mm pistons. I've also gone up to 40mm in the rear and maybe just now think a proportioning valve is needed; given that experience, you're not going to need a prop valve and may even want to experiment with disabling the OEM valve.

 

[Fishtail]

I've been considering the same thing. But I want to be sure I can use the same selection of wheels with the bigger brakes. Let us know what works for you. I still want to use the same wheels I have so I think the options will be narrowed down.

-Lou

 

[Andrew/USPWR]

Size matters. Stay with the bigger brakes
I like as much stopping power as I can get. I had Viper Speed put 6 piston Baer Alcon brake in the front and move the front brakes & rotors to the back with proportioning valve.

I tracked it at Sebring a month ago and the car brakes fantastic (all day long). Without abs,

The one thing I will say is that driving around town (and it is a daily driver) it squeals like crazy. At every single stop. I'm talking with Viper Speed and Performance Friction about some quieter pads now. Everyone says "that's race brakes" but it's a street car 1st. Track car 2nd.
So if having your car shriek to EVERY stop is going to bother you. Make sure you get the right pads.





2000 GTS Steel Grey
Six piston Bier claws up front, front brakes in back
Quaife Differential, GKH half shafts, alloy fly wheel,
short throw shifter, polished intakes, K&N air filters, Optima battery,

 

[Anthony - 98 GTS]

If you are going to drag race you can't run slicks and skinny's with the bigger caliper up front.

You will have to either change the front caliper everytime you go to the track or just run with 18" drag radials.

 

[Joseph Dell]

I think I'm going to go with 18" drag radials when I get to the track.

So here is the 2nd question... someone suggested putting the calipers from the front (original) on the back. Can I do that? Is it a good idea?

JD

 

[Tom F&L GoR]

Joe, not with the StopTech fronts. You'll have too much rear brake (putting the four piston fronts on the back) and it'll be so out of whack the proportioning valve you'll have to get won't be able to adjust enough. Remember, you're putting smaller than OEM calipers on the front, then you'd be putting those original size OEM calipers on the rear => your back brakes are then bigger than your front brakes. Very bad.

The StopTech brake upgrade is better for heat rejection and they provide front to rear balance. They aren't bigger in the sense that they are grabbing the rotor any harder.

http://www.stoptech.com/whitepapers/rear_brake_upgrade_is_bigger_better120601.htm

 

[Andrew/USPWR]

Actually I have the original back brakes AND the front brake on the back of my GTS. The original is the parking brake and the front brake is for stopping power .


Note: with the thicker front rotor in the back you'll need worn pads for the parking brake and you'll need about a 1/4 inch spacer so the wheel won't hit the caliper.








2000 GTS Steel Grey
Six piston Bier claws up front, front brakes in back
Quaife Differential, GKH half shafts, alloy fly wheel,
short throw shifter, polished intakes, K&N air filters, Optima battery,

 

[RedGTS]

I've followed brake threads for a while, and it seems that, while Stoptechs or other upgraded brakes make a big difference on the track, they don't necessarily make much difference on the street (i.e., by reducing stopping times significantly with the brakes cold). Is this true of all the potential brake upgrades, or is there a way to get SRT-like stopping distances on the street out of a Gen. II?

 

[Got Venom]

Ronnie,

I've heard rumors of Ted May of Valaya Racing in San Jose,Calif. testing on Gen II cars the Brembo brake system used on the new SRT-10's . He is just swapping out the old with the new, and should have results soon. Just give him an e-mail at [email protected]


Dennis Kimball

 

[Tom F&L GoR]

Ronnie, separate the concept of brakes into two characteristics - stopping power at each end of the car and heat rejection.

The OEM setup has a good size front caliper and a too small rear caliper. Under braking, you lock up the fronts and flat spot a tire(s). To balance the front to rear braking capability, StopTech created a smaller piston front caliper, I have a larger piston rear caliper. Both methods will work to get much closer to all four wheels wanting to lock up at about the same time. Or, an ABS system will do this for you, with far less tuning about what size each caliper is.

StopTech systems and other racing brakes also have larger calipers, larger rotors, and better airflow for cooling, because brakes create and then have to reject heat.

Whatever you can do to get better balance is going to feel much better on the street. Much. Then if you track the car also, you'll want to make sure you get rid of the brake heat. I think upgraded brakes on some cars (Boxsters?) aren't as noticeable if the car was balanced already; I paid for all my $$ spent experimenting in just a year at the rate I was going through AX tires.

 

[ByteMe]

Tom,
You mention ABS. Is it possible to retrofit ABS onto a 1997 GTS?

 

[Bob Woodhouse]

"Tom,
You mention ABS. Is it possible to retrofit ABS onto a 1997 GTS? "
I'll field that one Tom, and by the way listen to Tom you guys, he knows his stuff. On ABS, not retrofittable unless you want to float the price of half a new car at it. This takes knuckles, cpu's, tone wheels to just begin. If you want ABS, see Viper Speed or Autoform for a mostly MOPAR parts aftermarket kit develped specifically for Viper. Installed you are looking at around $7500, cheap in comparison.
In reading this thread I felt you may want to know Stop Tech can fit only the 13" rotor in the 17" wheel. If you run 18" then you can run the 14" rotor.
Call the boys at Stop Tech or read some of their great Technical articles at www.stoptech.com for additional accurate info. Any time you change the hydraulic ratios or rotor diameters you are playing with the front to rear brake balance. Let the experts help you. I made all the mistakes already. Another good site is www.thebrakeman.com
And yes, you can make a Viper stop like you caught your finger in a door jamb. As good as the SRT-10? Within a whisker or two yes. If you need anything, touch base with Mark or Nancy at www.woodhouseviper.com, we are dealers for both. Now I hate myself but hey.

 

[Tom F&L GoR]

If you're adventurous like Remo Hollenstein and me, you'll drool about doing this:
http://vca2.viperclub.org/forums/showflat.php?Cat=&Board=UBB2&Number=8417&Forum=UBB2&Words=stratus%20brake&Match=And&Searchpage=0&Limit=25&Old=allposts&Main=8410&Search=true#Post8417

But if you have common sense, then listen to Bob.

 

[RedGTS]

And yes, you can make a Viper stop like you caught your finger in a door jamb. As good as the SRT-10? Within a whisker or two yes.

Bob, are you referring to the Stoptech system specifically here, or something else?

Thanks to all for the advice.

 

[Vreracing]

Maybe not on this thread exactly, but I feel I can go faster if I can stop faster. Sort of a confidence issue.

I talked to JonB and the next thing I had in the mail was the StopTech 4 wheel system.

Probably the best improvement in the car I've made.

For street driving I felt the Stock brakes were substandard and certainly didn't give me the confidence I wanted.

 

[KepRght]

Is the stock ABS system on gen2 3 channel or 4?

Thanks