A new, affordable approach to Bullet Proofing the IRS
The following 2 users liked this post by Hiltonlo:
ajrothm (01-13-2018),
Metalhead140 (12-29-2017)
#162
Drifting
Member Since: Aug 2015
Location: NSW, Australia
Posts: 1,939
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C3 of Year Finalist (track prepared) 2019
Looks good! Have you got a picture of how the diff nose mounts to the crossmember? I assume you are changing to coilovers, as I don't see provision for a leaf spring? Have you weighed your new crossmember/mount? Any idea how much this might weigh compared to standard?
#163
Hub adapter to bolt the C7 hubs to the trailing arm
Wilwood brakes line up to the original locations. Will even be able to reuse my wheel speed sensor with an adjustment to 37 teeth instead of 40 like the original rotor had
Ended rotating the caliper to the 2 o’clock position to allow for easier bleeding
Trailing arm with coilover mount mocked up in car. Will need to shorten the CV about 7”. Coilover will be Viking C207 with a 300# spring per Viking engineers using data i provided. Hopefully will get them in the mail early next week
Wilwood brakes line up to the original locations. Will even be able to reuse my wheel speed sensor with an adjustment to 37 teeth instead of 40 like the original rotor had
Ended rotating the caliper to the 2 o’clock position to allow for easier bleeding
Trailing arm with coilover mount mocked up in car. Will need to shorten the CV about 7”. Coilover will be Viking C207 with a 300# spring per Viking engineers using data i provided. Hopefully will get them in the mail early next week
The following users liked this post:
ajrothm (01-13-2018)
#165
Thanks againg for taking use thru the process. One quick question, do you need 2007 and newer axles or will any 9.75 axles from a IRS fit. Thanks Don
#166
The following users liked this post:
sagebrush rebel (01-12-2018)
#167
Quick update, cradle test fitted for the final time. Coilovers mounted but will probably move the upper mount outward to stand the coilover up closer to vertical. It’s at a 30* angle there. Will be going into paint this weekend hopefully and final assembly next week
#169
The camera angle makes it look worse. It’s not parallel but it’s not as bad as that looks. The upper arm is shorter much like in a front a arm setup. Over all it gains less than 1/4* negative camber from ride height to full compression. At ride height the bars are basically parallel and at compression as shown in the pic, they are a little under 2* difference in angles of the bars
Last edited by Hiltonlo; 01-18-2018 at 12:32 PM.
#171
Al in, with lightweight willwood brakes and coilovers, I’m in this project $2400 using all new parts except the axles. I suspect this could duplicated with used parts for well under 2k. Reuse factory brakes and leaf spring and it could be done for $12-1500.
#172
Tech Contributor
Nice job, now what was your labor to build it as I am sure those will ask if it's feasible to market at kit. Keep us posted once you start to lay into it as well. Hope it has a long abusive life!
#173
#174
I plan to take it relatively easy on it for a month or so to break in the diff. Also don’t want to risk a break before TX2K in Houston in March so I’ll be keeping street tires on it until then. Once i get the drag pack back on for 2k then I’ll beat on it and see what happens
#175
Race Director
Nice!
#176
Tech Contributor
In my opinion, it would be hard to market. I’m speculating that there wouldn’t be a large market of people wanting to put a late model ford irs diff in their vette just Bc of brand loyalty. Most people can look past a 9” Bc it’s got a cult following, but a super 8.8 is unknown to most. I think with the other options on the market readily available, it would be hard to compete at a “kit” level. I posted this build mostly for other diy folks who may want to attempt a similar build. I stayed within the constraints of a bolt in setup as much as possible so there’s no reason this couldn’t be installed in any C3.
I agree as well the window for HP diff is small and getting smaller. Market kits are in the $8-$10k range which will pull it away from many owners who don't have deep pockets. I see there a scramble to take over Tom's market on HP diff builds, all promote them as expected but they don't have 40 years track record either.
Your build is one of the better ones I have seen without all the hype associated with it. Who knows this might work out for others that can do all the work like you did. I am impressed with your work.
#180
Drifting
Fantastic build! Don't let the nit pickers get to you, far as Im concerned it helps to create a better product than only having one set of eyes or thought process looking at it. I do have some questions about it if you dont mind.
1 Some of us would like to lower the rear of our cars without using flag poles for bolts on the leaf spring. How close does the diff sit to the bottom of the body?
2 Anything you would do differently now that you have completed it?
1 Some of us would like to lower the rear of our cars without using flag poles for bolts on the leaf spring. How close does the diff sit to the bottom of the body?
2 Anything you would do differently now that you have completed it?