1994 Big Block Road Racer project
11-11-2015, 08:45 PM
#41
Burning Brakes
I need help with offsets/backspacing from the C4 wheel guru's out there. L98TPI has PM'd me his thoughts. I want to hear from others before I have the wheels built. I need to run 345-35-18 Hoosiers on the rear and up front 335-18's. Probably 13" on the rear and 12.5" up front, but have no idea on the offset and backspacking. I am running coilovers, so I'll be able to adjust ride height etc to avoid rubbing, but I dont want this car sitting high just to run wider tires, that defeats the purpose! Does anyone road race with 345's on the back with no issues?
I run a 10" wheel up front. I've run 11" up front before and couldn't tell that it had any better grip.
11-12-2015, 10:09 AM
#42
11-19-2015, 11:45 PM
#44
Ok, a quick update. I've been talking to Shafiroff on the low-deck 615 and they definitely recommend going with a dry sump set up that they have used before in similar set ups.
It's a lot more money, but very good insurance to have.
More to follow soon!
It's a lot more money, but very good insurance to have.
More to follow soon!
11-22-2015, 06:26 PM
#45
Melting Slicks
For a member Brian Cunningham runs at 3:35 on the front if I recall correctly .
There is another member that did a pretty awesome build up of his car that is running at 3:45 rear tire . I believe it is Bill Brad he was going to discuss how we got it to fit but I don't ever recall seeing the exact explanation .
Good luck with the project, it sounds like it'll be awesome car
Last edited by qwiketz; 11-22-2015 at 06:29 PM.
11-27-2015, 05:59 PM
#48
Pro
IRS upgrade
https://www.corvetteforum.com/forums...r-section.html
12-01-2015, 05:14 AM
#50
Sounds like a cool project. Just curious. Why are you wanting 900 hp for a road race car? The TQ curve of that motor will be interesting getting on the throttle wot when exiting a corner.
540 wheel is a good number I would have thought on a light weight C4......
540 wheel is a good number I would have thought on a light weight C4......
06-29-2016, 08:12 PM
#54
From previous posts I've seen - fitting a BB into a C4 is not that easy - there will probably be interference with the front crossmenber unless the engine moves back a fair bit - and then there are trans fitment issues if you use anything like a stock torque arm. Yes, you can do some pretty serious surgery to the front crossmenber to avoid the interference issues, but spend some time thinking about your plans. (If you do some searching on this forum - you'll find a couple of posts with pics). You are going to need to fab up headers - nothing from the aftermarket is likely to fit.
I understand the idea of BB torque on a road course - but 415 or 427 small blocks are easy to do and will happily fit into the C4 Engine compartment. Aftermarket SBC heads flow phenomenally well, and if you aren't happy with about 550 ft lb of torque - you can always add boost...
A few other thoughts:
Most road race trannys and diffs require coolers - if you think about 12% driveline loss - that loss gets turned into heat. It doesn't take long for 50 HP of "loss" to get trannys and diffs quite warm.... Plan on installing coolers now - while you have the ability to get fittings installed (drain plugs and fill plugs are common cooler fluid hook-up points) - but if you look at the Tex and Jerrico gearboxes the NASCAR boys use - they can use fluid coming back from the cooler to improve lube to some areas in the tranny.
With that kind of power available - you are going to need massive brakes - and serious brake cooling (read that as a single duct from the fog lamp is NOT enough). Brake size is not about stopping power - even a stock C4 PBR caliper can lock a wheel at 120 MPH - it's about handling the heat that's generated in heavy - repeated brake usage.
While your roll bar / cage looks significantly better than many I've seen - it's not in the same league as a real "built from the ground up" race car. Assuming you can put the power down - if you are making 600 - 700 HP, you are going to have the same kind of power that NASCAR Trucks have !!! Eventually - either you are going to make a mistake or a component is going to fail, and with the kind of power you'll have available - you're going to be carrying a lot of speed when that happens. If you have a tire fail at speed - I don't care if your name is Prost or Foyt - you're just not going to be able to control the car. In a situation like that - the cage is what's going to save your life. It needs to be significantly overbuilt ...
I'm not trying to be a killjoy - but think about the energy that is going to be "dumped" if you have a high speed off. Keep that in mind when you are thinking about the roll cage construction.
I understand the idea of BB torque on a road course - but 415 or 427 small blocks are easy to do and will happily fit into the C4 Engine compartment. Aftermarket SBC heads flow phenomenally well, and if you aren't happy with about 550 ft lb of torque - you can always add boost...
A few other thoughts:
Most road race trannys and diffs require coolers - if you think about 12% driveline loss - that loss gets turned into heat. It doesn't take long for 50 HP of "loss" to get trannys and diffs quite warm.... Plan on installing coolers now - while you have the ability to get fittings installed (drain plugs and fill plugs are common cooler fluid hook-up points) - but if you look at the Tex and Jerrico gearboxes the NASCAR boys use - they can use fluid coming back from the cooler to improve lube to some areas in the tranny.
With that kind of power available - you are going to need massive brakes - and serious brake cooling (read that as a single duct from the fog lamp is NOT enough). Brake size is not about stopping power - even a stock C4 PBR caliper can lock a wheel at 120 MPH - it's about handling the heat that's generated in heavy - repeated brake usage.
While your roll bar / cage looks significantly better than many I've seen - it's not in the same league as a real "built from the ground up" race car. Assuming you can put the power down - if you are making 600 - 700 HP, you are going to have the same kind of power that NASCAR Trucks have !!! Eventually - either you are going to make a mistake or a component is going to fail, and with the kind of power you'll have available - you're going to be carrying a lot of speed when that happens. If you have a tire fail at speed - I don't care if your name is Prost or Foyt - you're just not going to be able to control the car. In a situation like that - the cage is what's going to save your life. It needs to be significantly overbuilt ...
I'm not trying to be a killjoy - but think about the energy that is going to be "dumped" if you have a high speed off. Keep that in mind when you are thinking about the roll cage construction.
Last edited by Purple92; 06-29-2016 at 08:13 PM.