Factory Five Racing Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
207 Posts
Discussion Starter #1
I will be starting my build in the next couple of weeks and plan on using the roadster as a street car that is taken to a couple of track days a year. I will be using a mark VIII 4.6 and IRS rear. Im looking for recommendations for transmissions, rear ratios, p/s or no p/s, tire size, ect... Any input would be very welcome. I will be using 245/45R17 up front and 315/35R17 summer tires for the street and will probably have a second set of wheels and tires for the track without a stagger. I understand that some have had probblems with getting there cars through tech with only one roll hoop. I will probably build with provisions to add the second roll hoop for those days Im at the track and remove it and install plugs when I am just driving it on the street. Does anyone have any experience with making and installing removable plugs? I have seen some pics like the one Im attaching but havent heard from anyone that has actually made them or used them. Thunderbolt raceway in NJ will be the home track. Does anyone have any track specific setup information? I ran my RX7 with 4:10 rears and had to lift on the long straight to keep from bouncing off the rev limiter. My tire diameter on the cobra will be significantly bigger but my redline will be about 1500 rpm lower. ...But exit speed and rate of accelleration and braking point will all be different as well. If anyone can give me info on top gear ratios for the different 5 speeds and recommend a decent rear ratio that would help immensely. Im not looking for ideal setups I just want something close because once its built i dont plan on changing ratios.
 

Attachments

·
Registered
Joined
·
2,291 Posts
Go with power steering. I have had both at track events and P/S is really a big help for reducing fatigue. I would go 3.55 rear with a TKO 500 or 600 with the .82 fifth gear. That makes fifth usable a the track but also OK on the street with the 3.55 rear. You will not have a problem with one roll bar unless you want someone to ride with you so go with the option you mention. Your tire sizes will work fine that is what I use. I have another set of wheels with track tires and would recommend that as well.
 

·
Too Cheap to paint!
Joined
·
6,248 Posts
Two hoops is a must.

I instruct at Thunderbolt, and if you have no previous experience, you're not going out without an instructor.

I only run the second hoop on track days and schools for student rides. I pull mine out, and made plugs from extra body material.. If you want, i can put up pics.

I have the tree-link rear. Much better on the track, no squat, tracks true.

Run the VPM sway bars.

3.55"s out back, and an extra set of rims with Kuhmo 710's.

Seriously research front air dams/spoilers. It's needed on these cars over 100 MPH.

Don't go goofy on the power, you will have a handfull with 350 HP.

Pay attention to the brakes, use GOOD pads.

Look back on a few of my threads here, some good info.

Where are you from?
 

·
Senior Charter Member
Joined
·
1,227 Posts
Chepsk8...YEAH POST PICS OF THE PLUGS. Did you bond studs to the under side of the body and use those to fasten the plugs? I would love to see that.
 

·
Premium Member
Joined
·
17,871 Posts
I started out with a street car, and had no plans for track time. But, now I'm hooked. And I'v had to change a few things along the way. From what I'v learned, I could have saved a lot of time and money if I had made the right changes during the initial build.

Good things I did:
- Full width roll bar. No longer a FFR option, but shouldn't be a problem for a local fab shop.

- VPM sway bars

- Manual brakes, with dual M/C. Excellent control and feel on the track and the street.

- Manual steering. Less weight, no fluid leaks. I like the feel, and it doesn't wear me out. P/S costs about 25hp, and I'd rather have that going to the track. My preferance.

- AN lines and fittings everywhere. Sure makes maintenance and changes easy.

- Dropped trunk floor - street, not track.


Things I changed:
- Rear Gear: 4.10 was nice on the street. But I ran out of gear much too soon even on the short stretch. Now I have 3.55, and considering 3.08.

- Differential: I started out with stock Ford LSD. Changed it to a detroit trutrak. It handles better, I don't know why. Since there are no clutch plates, it won't wear out.

- Brakes: Stock was fine on the street. Could easily lock the brakes at speeds <45 or so. But I burned them up pretty quickly on the track. Now I have Wilwoods on all 4 corners. Expensive, but on the track they're a real life saver. Literally. Quiet and responsive on the street, too.

- Brake Cooler: Inexpensive. Fairly easy to fab up. Really does make a differance.

- Oil Cooler: actually bothersome on the street, I wouldn't install one. But really needed on the track. For a 4.6, I would use a heat exchanger on the coolant outlet line.

- Accusump: Not that expensive, easy to install. It would have saved my first engine from a spun bearing. I would like a dry sump; but $$$$$.

- Air Dam: I tried one. It took all day of fitting and trimming to get it to sit right. It made a huge improvement in handeling. You could really feel the front tires dig on. But, It cost me 2 seconds on my lap time. So I took it off. I might try a smaller one this year.

- Fuel tank: Stock just doesn't cut it on the track. Towards the end of a 20 min session, the fuel will all move to the left side in a hard right turn. Then the engine goes lean for a few seconds. Not good. I'm going to upgrade to a fuel cell in a month or two. Your smaller engine probably won't have that problem; it will use less fuel in 20 minutes.

That's about all I can think of right now.
 

·
Registered
Joined
·
207 Posts
Discussion Starter #6
Chepsk8...YEAH POST PICS OF THE PLUGS. Did you bond studs to the under side of the body and use those to fasten the plugs? I would love to see that.
I second that request. Any and all photos of this setup would be greatly appreciated. I will most likely be going with dual roll bars and would be removing the passenger side if not both when Im not at the track. I really dont want open holes in the body.

Thanks for all the great info so far everyone, keep it coming.
 

·
Registered
Joined
·
207 Posts
Discussion Starter #7
Two hoops is a must.

I instruct at Thunderbolt, and if you have no previous experience, you're not going out without an instructor.

I only run the second hoop on track days and schools for student rides. I pull mine out, and made plugs from extra body material.. If you want, i can put up pics.

I have the tree-link rear. Much better on the track, no squat, tracks true.

Run the VPM sway bars.

3.55"s out back, and an extra set of rims with Kuhmo 710's.

Seriously research front air dams/spoilers. It's needed on these cars over 100 MPH.

Don't go goofy on the power, you will have a handfull with 350 HP.

Pay attention to the brakes, use GOOD pads.

Look back on a few of my threads here, some good info.

Where are you from?

Im from Mays Landing, NJ ("Jersey Represent"). Who do you instruct for? I can definitely see why an air dam would make a big difference but they are just so ugly. I might have to make that an easy on/off application too. As far as power goes, I figure I'll start stock and see how I like it. I hear these cars feel and perform like they have 50% more power than they do anyway. I plan on using cobra fronts and have not committed on rear brakes. Im not sure if I'm going to use Mark VIII calipers or cobra calipers. The VPM bars are very nice but a little pricy at $400 a pop.
 

·
Premium Member
Joined
·
17,871 Posts
You didnt have any issues with the VPM rear bar and the drop floor?
The only issue was the left bracket intruded into the corner of the dropped area. It was just a small amount, and not difficult to work around at all.



 

·
Junior Charter Member
Joined
·
265 Posts
Don't make the car too nice. I built my car to a show quality finish, and after 2 years of track time its really starting to show the wear and tear. If you are going to track the car, it will show the results. Also, build in all the safety you can, I am off to get a full track car now as the level of driver protetion in the street car is just not up where it needs to be. Track events are a blast, but being able to walk away from a mistake is very important.
 
1 - 10 of 10 Posts
Top