Front calipers on the back?

[ElDiablo Viper]

I have StopTech Big Brake kit in front. Is it possible to install my stock fronts on the back? I know that it was possible on the Corvette.

 

[McGuireV10]

Coincidentally I talked to a guy who wanted to do this only about two weeks ago. After investigating it rather thoroughly, his conclusion was that fabricating all of the brackets and so on would have been just as expensive as simply buying new rears outright.

 

[Stephen Yap]

There are brackets that will allow you to install the stock front calipers in the rear. I think viperspeed (Bobby Archer) sells them. The problem with doing that is your brake system's MC was not designed with those bigger piston sizes. What you will get is a spongy, long travel brake pedal. I recommend you get an aftermarket MC if you want to do something like that.

 

[Paolo Castellano]

There are brackets that will allow you to install the stock front calipers in the rear. I think viperspeed (Bobby Archer) sells them. The problem with doing that is your brake system's MC was not designed with those bigger piston sizes. What you will get is a spongy, long travel brake pedal. I recommend you get an aftermarket MC if you want to do something like that.

ElDiablo, I have had the Brembo Sprint Monoblock calipers up front and the stock fronts on the rear for several years now. As long as you have braided lines and a residual pressure valve you will have a hard pedal. My brakes are fantastic and have phenomenal pedal modulation.

Stephen, I was not aware there was an aftermarket MC that worked.

 

[Tom F&L GoR]

To give you some perspective, modifying the rear 36mm single piston caliper to a 40mm single piston gives you pretty close to ideal mechanical balance of front-to-rear clamping force. I think any greater piston area than that (i.e. the front calipers in the rear) would require a proportioning valve screwed down pretty good so you don't have too much rear brake.

Paolo, a residual pressure valve or a proportioning valve? I thought a residual valve was for drum brakes so they didn't require excess travel to reapply. A disc brake wouldn't (or shouldn't) do this since there's no return spring.

 

[ElDiablo Viper]

I have all 4 ss brake lines. How do I calibrate the balance? My front StopTechs are very good.

 

[Paolo Castellano]

To give you some perspective, modifying the rear 36mm single piston caliper to a 40mm single piston gives you pretty close to ideal mechanical balance of front-to-rear clamping force. I think any greater piston area than that (i.e. the front calipers in the rear) would require a proportioning valve screwed down pretty good so you don't have too much rear brake.

Paolo, a residual pressure valve or a proportioning valve? I thought a residual valve was for drum brakes so they didn't require excess travel to reapply. A disc brake wouldn't (or shouldn't) do this since there's no return spring.

Tom, I have both. From what I understand, the residual pressure valve is a piece that keeps some of the volume of brake fluid that goes out during braking in reserve(kind of like pressurizing) so you always have a hard pedal. Because when you put the stock fronts on the rear and add the Brembo Sprint monoblock 4-piston fronts, the total volume of fluid being pumped out by the brake master cylinder is greater than what the original volume with the stock fronts and rears. All I know is that it works. Everybody who can drive who has driven my car finds the pedal to be very firm and the pedal modulation for threshold braking is found almost immediately.

 

[Stephen Yap]

Paulo, my experience with an aftermarket rear caliper (Wilwood Dynalite) was a spongy, long travel brake pedal. I got the MC from Roe Racing but you can get aftermarket pieces from Tilton, Baer, etc.

 

[Tom F&L GoR]

ElDi, your proportioning valve normally calibrates the front to rear balance. If you don't like the OEM calibration, you can usually get an adjustable one to dial in more rear brake. But, as we usually complain about, the rear Viper calipers are too small, and for lots of reasons, you shouldn't reverse a proportioning valve and decrease line pressure to the front. So you're left with making the rear caliper physically larger.

Paulo, Understand completely what you have, how it works, and how it would feel. And you can't argue with success, so I'm asking more for the why it works so well. Residual valves on drum brakes were installed so that the return springs didn't push fluid back into the MC; they allowed the shoes to be pushed back by the drum, but the the check valve was there to keep the spring from pushing it back even more. There aren't any springs in a caliper, so theory says you wouldn't need one, and some places say that it might cause a disc brake caliper to slightly drag. Do you recall what pressure setting they are? Thanks.

 

[Paolo Castellano]

ElDi, your proportioning valve normally calibrates the front to rear balance. If you don't like the OEM calibration, you can usually get an adjustable one to dial in more rear brake. But, as we usually complain about, the rear Viper calipers are too small, and for lots of reasons, you shouldn't reverse a proportioning valve and decrease line pressure to the front. So you're left with making the rear caliper physically larger.

Paulo, Understand completely what you have, how it works, and how it would feel. And you can't argue with success, so I'm asking more for the why it works so well. Residual valves on drum brakes were installed so that the return springs didn't push fluid back into the MC; they allowed the shoes to be pushed back by the drum, but the the check valve was there to keep the spring from pushing it back even more. There aren't any springs in a caliper, so theory says you wouldn't need one, and some places say that it might cause a disc brake caliper to slightly drag. Do you recall what pressure setting they are?
Thanks.

Tom, I had this put in by a tuner whose name I refuse to acknowlege. I do not know exactly why it works, all I know is that the pedal was much harder after they put in the residual pressure valve. I love my brakes and that is that. This valve is approximately 3/8" in diameter and 2" long if that helps.

 

[malcoll]

Viper Speed sells the brackets to put front calipers on the rear... they are listed on their website...... what I am thinking is keep the OEM front calipers I have... and buy a second set of OEM front calipers for the rear?

Any thoughts?

 

[ElDiablo Viper]

Malcoll, do you have their web address? Thanks.

 

[jimandela]

keep us posted sounds very interesting!

 

[malcoll]

Here you go!
On the menu to the left... choose "online catalog"... then on the catalog page go down to "performance brakes"........
Near the bottom of the page...... says modify your own spindles or send to Viper Speed for modification?


http://www.viperspeed.com/new/default.htm

 

[Tom F&L GoR]

Malcolm, whoa! (pun) Search the board, this has been done before and with the same calipers front and back, you will have unbalanced the system too far such that the proportioning valve can't provide the final adjustment. From just fooling with the numbers (and a little bit of reading) you'll want the front calipers to provide roughly 80% of the piston area of your braking system. Look at the StopTech site, that's probably where I got that from.

 

[malcoll]

Tom,
I'll definitely check that out....... I was just thinking out loud about putting OEM fronts on the front and rear....
I just recently finished installing rear disc brakes on my 1969 Mustang Mach I.... and that install got me thinking about the Viper brakes.

Thankyou for the "heads up".... I'll make sure to fully research before I do anything.

Have a great holiday!

 

[Paolo Castellano]

Viper Speed sells the brackets to put front calipers on the rear... they are listed on their website...... what I am thinking is keep the OEM front calipers I have... and buy a second set of OEM front calipers for the rear?

Any thoughts?

Malcoll, it would be a bad move to put a set of fronts on both the front and the rear. Physics being what they are and weight transfer being what it is, here is why you would never want to do that:

1. The stock system has been engineered with a certain amount of piston area(and brake pad surface area) in the front and the rear. Just look at the stock front and rear brake pads....

2. #1 is because weight transfers towards the front of the car under braking which is simple physics.

So what happens if you put the same piston area AND brake pad swept area on both front and rear with the stock master cylinder and built in bias, you will have relatively too much rear brake which is not a good thingon the street or at the track. You could possibly put a really aggressive compound on the front and a lesser one on the rear, but I do not think this is the way to go.

If you want to do it right, go for a 4-corner Stoptech kit that has been engineered for the Viper brake master cylinder and weight transfer characteristics/etc...==> If you do not want to spend all this money, you at least have to get a set of front calipers with a greater total piston area as well as swept pad area, now put the fronts on the rears and get a proportioning valve and adjust it so the fronts lock slightly before the rears. Then you also have to re-attach your e-brake as well. Hope this helps.

 

[Paolo Castellano]

Paulo, my experience with an aftermarket rear caliper (Wilwood Dynalite) was a spongy, long travel brake pedal. I got the MC from Roe Racing but you can get aftermarket pieces from Tilton, Baer, etc.

Stephen, Sorry i did not see your post earlier. Sean used to have a different MC, but he told me they are no longer available.

 

[ElDiablo Viper]

Would my stock E-brake work on my 02 GTS? I was told that if I went all 4 Stoptech that I would have to buy an older e-brake to fit it would the same go for stock fronts?

 

[Paolo Castellano]

Would my stock E-brake work on my 02 GTS? I was told that if I went all 4 Stoptech that I would have to buy an older e-brake to fit it would the same go for stock fronts?

Adam, I would assume so. But could not say for sure as I have not had an E-brake for years as the so called tuner never hooked it back up. I bought the e-brake relocation system but one quick try told me I need to shim it differently to fit as the stock front rotor on the rear was too thick for proper spacing.