Brunton M-Spec 1,600 pounds and LS POWER!!
09-28-2014, 09:06 AM
#103
TECH Addict
iTrader: (19)
Join Date: Aug 2007
Location: Where the Navy tells me to go
Posts: 2,398
Received 106 Likes
on
88 Posts
There are a couple of guys that offer aftermarket shifters for the CTS-V - look for posts by "54inches" and "07CTS-V". 54 makes his own, while 07 modifies a Hurst for some other car.
Edit: Just looked back through the thread and it sounds like you've already got Creative Steel shifter bushings, which was another thing I would have recommended. Another thing you can do to help remove some slop is the "Home Depot mod" where the shifter arms actually attach to the tranny. You can replace the soft rubber bushings there with some grey plastic electrical conduit bushings. Or, you could make some aluminum ones, similar to what is on offer for Mustang folks.
Just spitballing here... perhaps as you start braking from high RPM you don't have much vacuum, so not much boost, and as you slow and the RPMs drop the vacuum builds and the added boost is causing the lock-up?
Look forward to some videos!
Edit: Just looked back through the thread and it sounds like you've already got Creative Steel shifter bushings, which was another thing I would have recommended. Another thing you can do to help remove some slop is the "Home Depot mod" where the shifter arms actually attach to the tranny. You can replace the soft rubber bushings there with some grey plastic electrical conduit bushings. Or, you could make some aluminum ones, similar to what is on offer for Mustang folks.
I also started experiencing a bit of front brake lock up in fast corners (like the 130 mph one at the end of the front straight). Not so much at weight transfer. I'm used to ABS cars, but that wasn't my mistake. It happened late in the braking. The proportioning valve is already allowing full pressure to the rear, so that isn't the issue. I may try a more aggressive rear compound and taller slicks for the next event.
Look forward to some videos!
Last edited by AAIIIC; 09-28-2014 at 09:31 AM.
05-26-2015, 11:01 PM
#104
TECH Fanatic
Thread Starter
iTrader: (15)
Join Date: Jun 2006
Location: Janesville WI
Posts: 1,155
Likes: 0
Received 0 Likes
on
0 Posts
So, I've been a little neglectful of updates to my build. Over the winter I had to pull the car basically entirely apart. I had to have the T-56 repaired. That meant pulling the engine, which meant pulling the interior, bodywork, steering , exhaust and part of the front suspension.
The good news was with the engine, shelf, scuttle, and side panel out of the way, I was set to update an area I was not entirely happy with (brakes and pedals).
After much thought I took a chance on Wilwood's dedicated pedal set up. I felt this was an area worthy of improvement. Firstly, I was experiencing front brake lock up that I could not work out with the adjustable proportioning valve (limiting pressure to the rear). I was also skeptical of the need for power brakes on the car. I was already in love with the manual steering, and wanted similar feel and feedback in the brakes. I also like the spartan nature and effort required to hustle the car around.
Anyway, I probably should have taken better pics of the original set up. I was never truly satisfied with the pedal placement. Original set up included a Wilwood pedal for clutch, another for brake, and a custom set up from Brunton to allow a lot of accelerator pedal travel to actuate the "fly by wire" pedal/sensor, that was mounted up on the shelf. Their set up worked, just like I said, room for improvement.
Here is the Wilwood pedal set up. It looks and feels more race car now!
I did have to move the pedals rearward to clear the trio. I moved the seat back to compensate, and am overall happier.
The main draw was going to manual brakes, and divorced two master cylinders for the front and rear brakes. This also allowed for a balance bar to further tune the bias. Willwood's tech line guy was extremely helpful! At his recommendation I went with a 3/4" front and 7/8" rear master cylinder. I kept the original wildwood master cylinder for the clutch (in fact we kept the hydraulics in tact with the motor pulled to avoid the pain of bleeding again). Engine out allowed for much easier brake line modification as the brake masters (Wilwoods new mini masters) were on the floor rather than the shelf.
I relocated the accelerator pedal for the LS engine harness to under the shelf also. We were able to work out a ratio that allows 6" of accelerator pedal travel. A must to modulate the arguably overkill (no such thing) power level.
Part of my brake upgrade also called for a cool kit I found at Flyin' Miata. They machine Wilwood 4 pots to accept an integrated emergency brake. This was a double score as I wanted more brake power, and the OEM Miata calipers oriented the emergency brake toward the tub of the car. The FM kit had the brake cable run straight toward the inside (perpendicular to the rotor).
I am impressed with the machine work on the kit. I was also able to upgrade to the slightly larger (but still cheap) Miata "sport" rotors.
The pretty purple anodizing didn't really fit my style, so I rattle canned them black quick prior to installation:
I also took the chance to install some longer ARP wheel studs. They went in with the hub in place (there is a relief cut out) which was a huge relief (see what I did there?!). I also needed the longer studs. I have to run a 13mm spacer on the front and rear to get the steel wheels to clear the beefy Wilwood calipers.
I am now running Wilwood BP20 pads front and rear. So far so good. No issues with fade whatsoever (during 20 minute HPDE sessions). Gotta love light cars!
The good news was with the engine, shelf, scuttle, and side panel out of the way, I was set to update an area I was not entirely happy with (brakes and pedals).
After much thought I took a chance on Wilwood's dedicated pedal set up. I felt this was an area worthy of improvement. Firstly, I was experiencing front brake lock up that I could not work out with the adjustable proportioning valve (limiting pressure to the rear). I was also skeptical of the need for power brakes on the car. I was already in love with the manual steering, and wanted similar feel and feedback in the brakes. I also like the spartan nature and effort required to hustle the car around.
Anyway, I probably should have taken better pics of the original set up. I was never truly satisfied with the pedal placement. Original set up included a Wilwood pedal for clutch, another for brake, and a custom set up from Brunton to allow a lot of accelerator pedal travel to actuate the "fly by wire" pedal/sensor, that was mounted up on the shelf. Their set up worked, just like I said, room for improvement.
Here is the Wilwood pedal set up. It looks and feels more race car now!
I did have to move the pedals rearward to clear the trio. I moved the seat back to compensate, and am overall happier.
The main draw was going to manual brakes, and divorced two master cylinders for the front and rear brakes. This also allowed for a balance bar to further tune the bias. Willwood's tech line guy was extremely helpful! At his recommendation I went with a 3/4" front and 7/8" rear master cylinder. I kept the original wildwood master cylinder for the clutch (in fact we kept the hydraulics in tact with the motor pulled to avoid the pain of bleeding again). Engine out allowed for much easier brake line modification as the brake masters (Wilwoods new mini masters) were on the floor rather than the shelf.
I relocated the accelerator pedal for the LS engine harness to under the shelf also. We were able to work out a ratio that allows 6" of accelerator pedal travel. A must to modulate the arguably overkill (no such thing) power level.
Part of my brake upgrade also called for a cool kit I found at Flyin' Miata. They machine Wilwood 4 pots to accept an integrated emergency brake. This was a double score as I wanted more brake power, and the OEM Miata calipers oriented the emergency brake toward the tub of the car. The FM kit had the brake cable run straight toward the inside (perpendicular to the rotor).
I am impressed with the machine work on the kit. I was also able to upgrade to the slightly larger (but still cheap) Miata "sport" rotors.
The pretty purple anodizing didn't really fit my style, so I rattle canned them black quick prior to installation:
I also took the chance to install some longer ARP wheel studs. They went in with the hub in place (there is a relief cut out) which was a huge relief (see what I did there?!). I also needed the longer studs. I have to run a 13mm spacer on the front and rear to get the steel wheels to clear the beefy Wilwood calipers.
I am now running Wilwood BP20 pads front and rear. So far so good. No issues with fade whatsoever (during 20 minute HPDE sessions). Gotta love light cars!
05-26-2015, 11:25 PM
#105
TECH Fanatic
Thread Starter
iTrader: (15)
Join Date: Jun 2006
Location: Janesville WI
Posts: 1,155
Likes: 0
Received 0 Likes
on
0 Posts
Another off season add on was to add some oil control. I had not yet noticed an issue, but guys with fast C6 vettes and another Stalker owner have found the limits of the Corvette pan's baffling. Improved Racing makes a set up to help with this. I figured it was cheap insurance. I considered an Accusump (in fact I have a whole set up I purchased for another LS racer), but for now I want to avoid the complication and room it would consume.
Of course I put off the undesirable task of dropping the pan until the day before my first event of the year (an HPDE at Blackhawk Farms).
The Improved Racing baffle can be purchased with a crank scraper/windage tray for the 6.2.
While I was at it I squirted the white cowl black w Plasti-dip (love that stuff) and threw on the seat covers (I raced it last year with bare aluminum seats). Looking sinister!
I completed my first HPDE on Saturday. I had not done an HPDE before because I thought I would miss having the competition of lap times (like the full course HSAX - Time Attacks I do). I am hooked! Tons of lap time for the money, and passing is addictive!!!
I then competed in the HSAX at Blackhawk Farms on the following Monday (Memorial Day). I set fast time of day (admittedly the crazy fast cars from the club weren't there like the 1,000 HP GT-R, LS swapped Datson or race ready Evo)!! A friend snapped a pic of another friend of mine (and alignment guy) who co-drove (I was #228, he was #288 ). This time he didn't embarrass me by setting a faster time (in my car), like he did in a low speed autocross last fall...
Of course I put off the undesirable task of dropping the pan until the day before my first event of the year (an HPDE at Blackhawk Farms).
The Improved Racing baffle can be purchased with a crank scraper/windage tray for the 6.2.
While I was at it I squirted the white cowl black w Plasti-dip (love that stuff) and threw on the seat covers (I raced it last year with bare aluminum seats). Looking sinister!
I completed my first HPDE on Saturday. I had not done an HPDE before because I thought I would miss having the competition of lap times (like the full course HSAX - Time Attacks I do). I am hooked! Tons of lap time for the money, and passing is addictive!!!
I then competed in the HSAX at Blackhawk Farms on the following Monday (Memorial Day). I set fast time of day (admittedly the crazy fast cars from the club weren't there like the 1,000 HP GT-R, LS swapped Datson or race ready Evo)!! A friend snapped a pic of another friend of mine (and alignment guy) who co-drove (I was #228, he was #288 ). This time he didn't embarrass me by setting a faster time (in my car), like he did in a low speed autocross last fall...
05-27-2015, 02:55 PM
#107
On your brake kit, is it just the adapters for the calipers that they sell? Or do they come with calipers? Also for the rotors, were they from the newer Miata and not something aftermarket? I have been looking for a big brake kit for my Bug and I think you have the answer I am looking for. I currently have 94 Miata spindles on it (calipers and rotors to be decided). What year spindles did your car come with?
Your car is looking good BTW!
Your car is looking good BTW!
05-27-2015, 03:05 PM
#108
TECH Fanatic
Thread Starter
iTrader: (15)
Join Date: Jun 2006
Location: Janesville WI
Posts: 1,155
Likes: 0
Received 0 Likes
on
0 Posts
On your brake kit, is it just the adapters for the calipers that they sell? Or do they come with calipers? Also for the rotors, were they from the newer Miata and not something aftermarket? I have been looking for a big brake kit for my Bug and I think you have the answer I am looking for. I currently have 94 Miata spindles on it (calipers and rotors to be decided). What year spindles did your car come with?
Your car is looking good BTW!
Your car is looking good BTW!
Flyin' Miata machines the Wilwood calipers for those e-brake parts. So they come as an assembly.
The rotors are indeed from a later Miata. My originals were 99 Miata (non-sport). They newer ones are about 1" larger.
I'm told my spindles front and rear are 99 Miata. So they should be like yours. Flying' Miata also has some nice, larger front kits. I would run those already, but my spindles came with the smaller brackets for the Wilwoods, welded on. Bruton uses the smaller rotors, and 13" race wheels. If your front spindles are still stock, you have lots of options for bolt on brake kits.
06-25-2015, 04:04 PM
#111
TECH Fanatic
Thread Starter
iTrader: (15)
Join Date: Jun 2006
Location: Janesville WI
Posts: 1,155
Likes: 0
Received 0 Likes
on
0 Posts
Cut and pasted from another forum (after scaling it looks like I should change my title...):
I'm not 100% finished with my car yet (M-spec #007), but have been racing it since last fall. I don't have it all the way sorted yet but am very happy with its performance.
I don't have my rear body work, lights or front fenders mounted yet. But I did mock up my rear body work when I scaled it.
ROAD COURSE
It is hard to compare road course times I since we are scattered out throughout the country (and some outside the country I'm sure). But at my home track, Blackhawk Farms Raceway I have set fast time of day at the last two events! *I race a format called High Speed Auto Cross (HSAX). This is a full track run, from a standing start, no cones.
My first time out (09/14) I ran a best time of 1:19.760. That is pretty quick, especially for a first event. For reference the fast time I ever ran with my old 02 Z28 was a 1:25.809 (a then class record on street tires). The current track record was set that day by a 1,000 HP, tuned GTR at 1:14.
I came back after a tire and brake change this season and have set FTD at both events running a 1:19.062 at the first event and a 1:17.321 at the next! I think with some aero, seat time and stickier tires that GTR's record may fall! Again, for reference the 2nd fastest car at my recent event was brand new Z28 (GM's new track toy) and it ran a 1:20.xxx. Man was it fun passing him and Z06 Corvettes in the HPDE that weekend!
1/4 MILE DRAG STRIP
I know these cars are not set up to be drag racers, but with the power to weight I knew it would be fun.
In 2014 I ran at a cold autumn open track night. Tires spinning well past 1/2 track I ran a best of:
12.336 @123.84 mph! *Not bad, but due to some issues I was not able to do a burn out, and the road race tires were not ideal. My 60' was 2.261...
This year I went back, still on my vintage road race 25.5x10.0x15 Hoosier bias plies, but this time I had a warmer track and did a good burn out. *Best run was:
11.429 @124.01 The big difference was the more respectable 1.815 60'.
I have some drag radials coming. I'm hoping to be in the 10's next time around.
WEIGHT
A racer friend let me borrow his scales this week. My car is a M-spec w the classic hood, an LS3, and T-56. I'm a little heavy though with the 15x10 steel race wheels.
1711 pounds with fluids (not quite full gas tank).
Empty it has a 50.5/49.5 front/rear balance.
With me in the car it weighs 1894 with a 47.7/52.3 weight balance.
0-60 Time
I haven't had a chance to capture that number, but I am eager to see what you other owners are finding. I'm guessing it will be quite impressive when I get the drag radials.
I'm not 100% finished with my car yet (M-spec #007), but have been racing it since last fall. I don't have it all the way sorted yet but am very happy with its performance.
I don't have my rear body work, lights or front fenders mounted yet. But I did mock up my rear body work when I scaled it.
ROAD COURSE
It is hard to compare road course times I since we are scattered out throughout the country (and some outside the country I'm sure). But at my home track, Blackhawk Farms Raceway I have set fast time of day at the last two events! *I race a format called High Speed Auto Cross (HSAX). This is a full track run, from a standing start, no cones.
My first time out (09/14) I ran a best time of 1:19.760. That is pretty quick, especially for a first event. For reference the fast time I ever ran with my old 02 Z28 was a 1:25.809 (a then class record on street tires). The current track record was set that day by a 1,000 HP, tuned GTR at 1:14.
I came back after a tire and brake change this season and have set FTD at both events running a 1:19.062 at the first event and a 1:17.321 at the next! I think with some aero, seat time and stickier tires that GTR's record may fall! Again, for reference the 2nd fastest car at my recent event was brand new Z28 (GM's new track toy) and it ran a 1:20.xxx. Man was it fun passing him and Z06 Corvettes in the HPDE that weekend!
1/4 MILE DRAG STRIP
I know these cars are not set up to be drag racers, but with the power to weight I knew it would be fun.
In 2014 I ran at a cold autumn open track night. Tires spinning well past 1/2 track I ran a best of:
12.336 @123.84 mph! *Not bad, but due to some issues I was not able to do a burn out, and the road race tires were not ideal. My 60' was 2.261...
This year I went back, still on my vintage road race 25.5x10.0x15 Hoosier bias plies, but this time I had a warmer track and did a good burn out. *Best run was:
11.429 @124.01 The big difference was the more respectable 1.815 60'.
I have some drag radials coming. I'm hoping to be in the 10's next time around.
WEIGHT
A racer friend let me borrow his scales this week. My car is a M-spec w the classic hood, an LS3, and T-56. I'm a little heavy though with the 15x10 steel race wheels.
1711 pounds with fluids (not quite full gas tank).
Empty it has a 50.5/49.5 front/rear balance.
With me in the car it weighs 1894 with a 47.7/52.3 weight balance.
0-60 Time
I haven't had a chance to capture that number, but I am eager to see what you other owners are finding. I'm guessing it will be quite impressive when I get the drag radials.
06-26-2015, 12:52 PM
#113
TECH Fanatic
Thread Starter
iTrader: (15)
Join Date: Jun 2006
Location: Janesville WI
Posts: 1,155
Likes: 0
Received 0 Likes
on
0 Posts
My local track is pretty friendly on test and tune nights. The tech guy told me to have a fire jacket next time since I ran 11s. I'll do that and see what they say when I run 10s (fingers crossed). The driveshaft is surrounded by square tube, so I think that may count as a driveshaft loop. If not I will install one.
Drag racing is just a side thing for me, this is a road race car. I don't claim to know the NHRA rule book. What else are you thinking I need?
06-26-2015, 02:26 PM
#114
I love this build! This thing is awesome.
Did you ever figure out the fan and cooling issues? The rad did look a little small. My first step probably would have been a lower temp thermostat.
The only thing I would change is the trans! Having a CTS-V T56 myself, I know the remote shifter sucks. I also bet that 1st gear is worthless in that light car. If I were you I'd be looking to get a racing trans for that considering that racing is the car's primary purpose.
A Richmond or Jerico 4 or 5 speed would do you some good and make it a totally different car (in a good way).
Did you ever figure out the fan and cooling issues? The rad did look a little small. My first step probably would have been a lower temp thermostat.
The only thing I would change is the trans! Having a CTS-V T56 myself, I know the remote shifter sucks. I also bet that 1st gear is worthless in that light car. If I were you I'd be looking to get a racing trans for that considering that racing is the car's primary purpose.
A Richmond or Jerico 4 or 5 speed would do you some good and make it a totally different car (in a good way).
06-26-2015, 02:53 PM
#115
TECH Fanatic
Thread Starter
iTrader: (15)
Join Date: Jun 2006
Location: Janesville WI
Posts: 1,155
Likes: 0
Received 0 Likes
on
0 Posts
I love this build! This thing is awesome.
Did you ever figure out the fan and cooling issues? The rad did look a little small. My first step probably would have been a lower temp thermostat.
The only thing I would change is the trans! Having a CTS-V T56 myself, I know the remote shifter sucks. I also bet that 1st gear is worthless in that light car. If I were you I'd be looking to get a racing trans for that considering that racing is the car's primary purpose.
A Richmond or Jerico 4 or 5 speed would do you some good and make it a totally different car (in a good way).
Did you ever figure out the fan and cooling issues? The rad did look a little small. My first step probably would have been a lower temp thermostat.
The only thing I would change is the trans! Having a CTS-V T56 myself, I know the remote shifter sucks. I also bet that 1st gear is worthless in that light car. If I were you I'd be looking to get a racing trans for that considering that racing is the car's primary purpose.
A Richmond or Jerico 4 or 5 speed would do you some good and make it a totally different car (in a good way).
As for cooling, I swapped out the Evan's waterless coolant for some plain old distilled water and water wetter. It is significantly better now. I may still add a bigger fan (though I would have to switch to pusher). It stays cool when moving so I primarily doubt the fan and water pump, not as much the rad.
I went with a CTS-v trans simply because I had it already. I shortened the handle and put harder bushings in. I'm happy with the shifting. I do intend to street drive the car eventually so the ODs will come in handy. 1st gear is just for putting it on the trailer (I launch in 2nd) but same deal with any T-56 in this car. If I had it to do over again a simple, lighter, dog ringed box would have been my first choice due to the reduced weight. But I'm not sure I am willing to go through the trouble of converting now.
That said a lighter clutch an lighter trans would make a nice improvement... Maybe after I get the body and aero sorted...
06-26-2015, 03:08 PM
#116
Guys with similar engine combo made 419 RWHP, so that makes me believe 500 HP flywheel. I do intend to get some chassis dyno numbers and a tune.
My local track is pretty friendly on test and tune nights. The tech guy told me to have a fire jacket next time since I ran 11s. I'll do that and see what they say when I run 10s (fingers crossed). The driveshaft is surrounded by square tube, so I think that may count as a driveshaft loop. If not I will install one.
Drag racing is just a side thing for me, this is a road race car. I don't claim to know the NHRA rule book. What else are you thinking I need?
My local track is pretty friendly on test and tune nights. The tech guy told me to have a fire jacket next time since I ran 11s. I'll do that and see what they say when I run 10s (fingers crossed). The driveshaft is surrounded by square tube, so I think that may count as a driveshaft loop. If not I will install one.
Drag racing is just a side thing for me, this is a road race car. I don't claim to know the NHRA rule book. What else are you thinking I need?
Roadster info around page 18...
http://www.nhra.com/UserFiles/file/G...egulations.pdf
06-26-2015, 05:02 PM
#117
Whoa, this is such a cool build! It was so much fun to read through each page and then see the results of your hard work in the form of awesome performance figures! Congrats and enjoy it!
07-06-2015, 10:28 PM
#118
please keep posting updates. I'm living vicariously through you.
This car is sick... I'm pretty damn sure I'm going to build one in the future, just got a house though and I need to figure out the Massachusetts Kit car laws clusterfuck
This car is sick... I'm pretty damn sure I'm going to build one in the future, just got a house though and I need to figure out the Massachusetts Kit car laws clusterfuck
07-31-2015, 10:25 PM
#120
The Exocet is far stiffer, lighter, wider, and has a larger interior space - as well as uses off the shelf miata suspension. It's a bit cheaper, is made from mostly round tube instead of square. I think the exocet is a little easier to put together, looking at the Brunton kit - and certainly has a ton more room to work on stuff. Buyer's preference really. I should have mine together before winter.