The VIPER Garage
User Info
Welcome, Guest. Please login or register.
September 18, 2018, 05:55:25 PM

Login with username, password and session length
Search:     Advanced search
News
Pick Your ViperGarage Theme
Forum Stats
24619 Posts in 1934 Topics by 827 Members
Latest Member: dmillerc6
Home Help Search Calendar Login Register
The VIPER Garage  |  How To Instructions  |  How-to section  |  Wilwood 12.25 in brakes for 15 in rims on Viper rear
« previous next »
Pages: [1] Go Down Print
Author Topic: Wilwood 12.25 in brakes for 15 in rims on Viper rear  (Read 1589 times)
RTTTTed
Owner
Administrator
Hero Member
*****
Offline Offline

Posts: 7724


Viper Nation - ezine
« on: October 11, 2015, 11:32:59 AM »

The Viper comes with a Dana Super 44 rear differential which can be easily upgraded to handle mega horsepower.  Todd Nelson (American Racing Technologies) reported that he has run 3000whp through a S44.  My 1500whp TT GTS has raced on slicks and done 8 sec launches thought the A.R.T. built Quaife equipped S44.  One issue of the S44 is that the highest gear ratio (excepting custom gear sets as offered by Unitrax) available is 3.07.  With the race transmissions top gear is going to be .75 OD which limits the car to only 196mph with Gen 1 or Gen 2 tires which are a 26in diameter.  With 19in newer Gen tires that diameter 27.6in the top speed is still only 207mph.  Stock overdrive gear ratio of .5 overdrive is geared for over 300mph?  The stock helical cut OD gears are too weak for a big hp engine.

The answer to the gear ratio is TIRES.  Shorter and Taller tires can adjust the effective gear ratio.  28in tires (R6s and 14.5 x 16 x 28in) will rub on the inner tubs and wear through them.  For 28 and taller tires the frame, support and seat firewall all need to be modified, which will allow use of 30in tall tires allowing nearly 250mph top speed.  The Inner Wheelwell modifications are posted in a different thread.  This thread is going to show installation of 12.25in Wilwood rotors and 4 piston calipers to the rear of my 99 TT GTS.  The modification allows use of 15 inch rims.  15in rims will support any type and size tire that is made for racing being the most common size.  The stock 14in brakes of Gen 3 and newer Vipers requires mods for running 18in rims reliably.  Gen 1 and Gen 2 can run slicks on CCW 16in drag pack wheels, but NOT ABS cars.  17in wheels do fit all Gen 1 and 2 cars, except for the ones with newer 14in brakes, like both of mine.

To start; Jack and support back of car with jack stands or use hoist.  Remove wheels.  Then rear calipers need to be removed.  My TT is equipped with Mark Williams axles which required me to also remove the wheel hubs and the upper A arm to change over the Hub bolts and install bracket.  You may not need to do that.  The stock spindle has cast aluminium ears towards the front of the car which is the caliper mounts.  These smaller brakes can also be used on the front of the car (not recommended unless you have a lightweight race car) which has the ears behind the spindle.  I used a Sawzall reciprocating saw to cut off the ears close to the Wheel Hub.  I then used a 5in angle grinder to smooth and remove sharp edges as well as clean the casting flash from the rest of the spindle.  Removing the casting flash lightens, cleans up and strengthens the parts (although not significantly).  I then used a flat bastard file to smooth the spindle cuts.   

The Wilwood light weight rotors use an aluminium Hat to significantly lighten the unsprung weight of the car.  It is generally understood that unsprung weight removal is equal to double the weight of sprung weight in effectiveness.  I would guess that this kit is about 12lbs lighter per wheel.  100# less weight is normally equal to a .1sec quicker ET on the quarter mile.  15# lighter wheels and tires with an additional 12# per rear wheel equals a weight loss of 54# and supposedly also a .1 sec quicker ET.
Logged
1999 1200rwhp TT GTS - ART, 2001 Roe sc GTS- (4 sale), 440 Duster restomod (sold), 3x Stealth TTs, 92 Daytona IROC with T3, 580whp/1080wtq Cummins pickup.
RTTTTed
Owner
Administrator
Hero Member
*****
Offline Offline

Posts: 7724


Viper Nation - ezine
« Reply #1 on: October 11, 2015, 11:42:09 AM »

The aluminium plate bracket fits over the rear of the spindle and uses 3 or the hub bolts (Longer bolts need to be used) to hold it in place.  The bracket has new caliper ears facing to the front of the car. 

I found that the shaved side of the bracket faces towards the car, which means that it has no purpose - on my car.  I suspect that the bracket may be shaved to fit Gen 3 spindles?
« Last Edit: October 11, 2015, 04:45:05 PM by RTTTTed » Logged
1999 1200rwhp TT GTS - ART, 2001 Roe sc GTS- (4 sale), 440 Duster restomod (sold), 3x Stealth TTs, 92 Daytona IROC with T3, 580whp/1080wtq Cummins pickup.
RTTTTed
Owner
Administrator
Hero Member
*****
Offline Offline

Posts: 7724


Viper Nation - ezine
« Reply #2 on: October 11, 2015, 02:46:32 PM »

The kit requires me to install the caliper bolts behind the rotors, into the calipers and then thread into the mounting bracket.  Seems like a lot of extra work to thread bolts in while caliper is hooked over the rotor and not much room for the bolts.  Other choice would be to disassemble the caliper, botl the back half to the bracket and then bolt the front half of the caliper back to the rear half.

My choice was to drill the caliper holes to 7/16" and thread the caliper holes.  I drilled the brackets to 1/2" to allow the bolts through the brackets from behind, through the mounting bracket and thread into the Calipers.  The calipers mounting behind the brackets instead of sliding over them is unique.  Threading the calipers makes everything work like normal and much easier to change rotors, brake pads etc.
« Last Edit: October 11, 2015, 06:47:27 PM by RTTTTed » Logged
1999 1200rwhp TT GTS - ART, 2001 Roe sc GTS- (4 sale), 440 Duster restomod (sold), 3x Stealth TTs, 92 Daytona IROC with T3, 580whp/1080wtq Cummins pickup.
RTTTTed
Owner
Administrator
Hero Member
*****
Offline Offline

Posts: 7724


Viper Nation - ezine
« Reply #3 on: October 11, 2015, 05:48:33 PM »

I compared the size of the Gen 2 rear brakes to the Wilwoods.  The Wilwood brake pads are are square shaped similar to the Gen 2 Front brake pads and much larger than the Gen 2 V shaped rear pads.  The Wilwood pads are only slightly smaller than the Gen 2 Front pads (see pic).  The Gen 2 rear rotors are slightly larger diameter, but although a similar width of friction surface the pads are much smaller.  The Gen 2 Front rotors are significantly larger in diameter AND friction surface is a quarter inch wider.  Gen 2 fronts are the best of the three with the Gen 2 rears being the smallest and worst for stopping power with only 1 piston, while both the other 2 types of brakes are 4 piston with the front Brembos having larger pistons, larger brake pads, larger diameter rotors and wider friction surface.

Using large bolts into the caliper I needed to drill out the brackets for the new half inch bolts.

I also decided that I would prime and paint all the new bright aluminium of the brackets.  I used a Stainless Steel epoxy style of paint for durability and corrosion prevention.



Logged
1999 1200rwhp TT GTS - ART, 2001 Roe sc GTS- (4 sale), 440 Duster restomod (sold), 3x Stealth TTs, 92 Daytona IROC with T3, 580whp/1080wtq Cummins pickup.
RTTTTed
Owner
Administrator
Hero Member
*****
Offline Offline

Posts: 7724


Viper Nation - ezine
« Reply #4 on: October 11, 2015, 06:07:52 PM »

With the calipers and brackets drilled, threaded and painted I already bolted the rotor hats to the rotors with the supplied allen head bolts.  I used a hammer to add a half turn to lock the bolts.  I also used never seize on the threads so that the unit will come apart eventually if I need it to. 

The bottom of the spindle needed to be ground for clearance to allow the rotor to sit flat on the wheel hub.  I pushed the rotor onto the wheel studs and used a black marker to indicate where the inside edge of the rotor hit the spindle.  I ground the aluminium spindle with my 5in angle grinder.  To prevent the disc from getting plugged (because of using a steel disc to grind aluminium) I sprayed the grinding surface with WD40.  I ground and checked, ground and checked, until my wheel assembly would turn without touching the spindle.  Once I had a bit over 0.1in clearance I cleaned the earlier areas I had ground and cut with brake clean then primed and painted with the SS Epoxy paint. 

The caliper has a sticker over the brake line fitting hole in the middle of the back side that says, 1 eight NPT thread.  This measurement will allow me to go to town and have 2 Stainless Steel brake lines.  The lines could also be ordered from BBG since he has the materials on hand.
Logged
1999 1200rwhp TT GTS - ART, 2001 Roe sc GTS- (4 sale), 440 Duster restomod (sold), 3x Stealth TTs, 92 Daytona IROC with T3, 580whp/1080wtq Cummins pickup.
RTTTTed
Owner
Administrator
Hero Member
*****
Offline Offline

Posts: 7724


Viper Nation - ezine
« Reply #5 on: October 11, 2015, 06:11:14 PM »

I finish assembled the complete brake assy (other than the missing brake lines).

I will add that with the wheels hanging in the air the inside edge of the 15 x 10in wheel is touching the Upper Ball Joint grease nipple, use caution.  With my MW axles the CV joints are so massive that the large allen head bolts of the CV joint contact the suspension mounting bolts of the lower A arm when the wheel is hanging in the air as well.  The picture shows the Bogart 15 x 10 in custom made racing wheels.
« Last Edit: October 11, 2015, 06:17:15 PM by RTTTTed » Logged
1999 1200rwhp TT GTS - ART, 2001 Roe sc GTS- (4 sale), 440 Duster restomod (sold), 3x Stealth TTs, 92 Daytona IROC with T3, 580whp/1080wtq Cummins pickup.
RTTTTed
Owner
Administrator
Hero Member
*****
Offline Offline

Posts: 7724


Viper Nation - ezine
« Reply #6 on: October 26, 2015, 12:14:05 PM »

Drummond's rear brake kit comes with plain cheap rotors and semi metallic pads.  Going extreme speeds means I want the best high speed parts so I returned the plain rotors for Black high carbon steel drilled/slotted rotors for an extra shipping cost and $169.  These rotors are also specially vented between the friction surfaces and that requires a specific direction of spin so they must be installed using the small directional arrows stamped into the surface near the edge.  Part #160 - 7106 - BK for the rotors.  The alum hats are #171 - 2233.

I also bought Ceramic pads from EBC ('Reds') for the extreme speeds of the half mile and mile events.  Steve Drummond said that the semi metallic are used to hold the car at the lights with an automatic.  I peeled and stuck the anti squeal pads to the back of the brake pads and trimmed off the excess before installing the pads into the caliper then mounting on car.

The brake lines were a Pain.  I bought 1/8NPT to -3AN  fittings (WIL 220-6956) to screw into Calipers and then SS brakelines (offroad racing) 22" long with a 90 degree bend (#63011722ERL) to screw onto the fittings.  Another fitting to adapt the SS line to the factory steel brake line is required for each side as well.  Female inverted flare end to male 3AN for the SS line.  Steel Gen 2 brake line is a 3/8" 24 ...  (Mark - IPSCO)  Gen 3 went to metric.
« Last Edit: September 17, 2016, 06:36:13 PM by RTTTTed » Logged
1999 1200rwhp TT GTS - ART, 2001 Roe sc GTS- (4 sale), 440 Duster restomod (sold), 3x Stealth TTs, 92 Daytona IROC with T3, 580whp/1080wtq Cummins pickup.
RTTTTed
Owner
Administrator
Hero Member
*****
Offline Offline

Posts: 7724


Viper Nation - ezine
« Reply #7 on: October 31, 2015, 07:24:49 PM »

I installed the Ceramic pads and used the allen head bolts to attach the high carbon steel slotted rotors to the lightweight aluminium 'hats'.  When I bolted the calipers to the adapter plates I found the pads to be a little more than 0.1" ABOVE the friction surface of the rotor.  The adapter holes for the calipers were too high in the adapter ...  The friction face of the pads can be seen in the first picture.

The brakes of a 200+mph car cannot be wasted.  I will probably make new adapters with the holes moved toward the center of the axle. However, I would like to finish this project and I filed angled slots into the adapters I slotted the holes inward and down so that stepping on the brakes would push the calipers to the bottom of the slots if the bolts were loose - which they aren't. 

The brake pads are now fitted to the friction surface and none of the braking surface will be wasted. 
Logged
1999 1200rwhp TT GTS - ART, 2001 Roe sc GTS- (4 sale), 440 Duster restomod (sold), 3x Stealth TTs, 92 Daytona IROC with T3, 580whp/1080wtq Cummins pickup.
RTTTTed
Owner
Administrator
Hero Member
*****
Offline Offline

Posts: 7724


Viper Nation - ezine
« Reply #8 on: September 17, 2016, 06:28:27 PM »

I bought Mickey Thompson ET Street 'R' Drag Radials for my TT GTS for Shif Sector Halfmile event.  With the car on the dyno under boost at 1400whp the car squatted and the lower ball joints as well as the upper grease nipples touched and ground away some of my inner wheel barrel.  I removed the tires and ground the lower bal joints to the edge of the cotter pin holes.  We removed the upper grease nipples and chopped them short.  The right side still touched so I'll need to remove even more material from that lower ball joint.  Probably lock tite the nut and grind another 1/8" material off the nuts and shafts.  Not room for the cotter pins it seems.
« Last Edit: September 17, 2016, 08:45:51 PM by RTTTTed » Logged
1999 1200rwhp TT GTS - ART, 2001 Roe sc GTS- (4 sale), 440 Duster restomod (sold), 3x Stealth TTs, 92 Daytona IROC with T3, 580whp/1080wtq Cummins pickup.
RTTTTed
Owner
Administrator
Hero Member
*****
Offline Offline

Posts: 7724


Viper Nation - ezine
« Reply #9 on: September 18, 2016, 01:24:02 PM »

Wheelwell Tire fitment is posted on this thread http://thevipergarage.com/index.php/topic,6032.0.html   (with pics)

To summarize: 28" tall tires fit inside the wheelwells with 1 5/8" space to inner plastic wheel tubs.  That should allow a 29.5" tall tire to fit within the plastic wheeltubs.  30" should be a fit if the plastic wheel tubs are replaced with aluminium sheet metal
Logged
1999 1200rwhp TT GTS - ART, 2001 Roe sc GTS- (4 sale), 440 Duster restomod (sold), 3x Stealth TTs, 92 Daytona IROC with T3, 580whp/1080wtq Cummins pickup.
Pages: [1] Go Up Print 
« previous next »
 

SMF 2.0.2 | SMF © 2011, Simple Machines | Theme by nesianstyles | Buttons by Andrea