Miata Turbo Forum - Boost cars, acquire cats.

Miata Turbo Forum - Boost cars, acquire cats. (https://www.miataturbo.net/)
-   Suspension, Brakes, Drivetrain (https://www.miataturbo.net/suspension-brakes-drivetrain-49/)
-   -   V8 Roadsters Cadillac Getrag Differential. INSTALLED. (https://www.miataturbo.net/suspension-brakes-drivetrain-49/v8-roadsters-cadillac-getrag-differential-installed-83274/)

slmhofy 03-20-2015 12:14 AM

I see your fuel cell, but I can't quite make out where it's at and where the PPF is.

If the getrag kit moves the back of the PPF over, then there must be enough slop/room in the front for it to not be a problem. I unbolted the front a few days ago and left the back bolted in, and then was able to put the front bolts back in with out much issue when I was done.

guttedmiata 03-20-2015 07:39 AM

Yeah, that's an old pic and the whole rear subframe is out. I was only showing how low the cell is mounted so when I said the ppf hits it, people aren't scratching their heads trying to figure out where my fuel cell is. I'm gonna leave the mount bracket in place and pull the diff and get the ppf on it and try to get it up there. If that doesn't work, which it doesn't look like it will, we will need to make a new fuel cell.

guttedmiata 03-20-2015 06:24 PM

Wouldn't go. Time to build another fuel cell. :facepalm:

slmhofy 03-20-2015 06:58 PM

Blahh. Sorry about that. If it's any condolence, you're going to absolutely love the gears. I think about it almost every time I drive the car. I'd say first is still a little short, but 2-5 is amazing.

guttedmiata 03-20-2015 10:01 PM


Originally Posted by slmhofy (Post 1217098)
Blahh. Sorry about that. If it's any condolence, you're going to absolutely love the gears. I think about it almost every time I drive the car. I'd say first is still a little short, but 2-5 is amazing.

Doing all of this to only use 2nd gear. ;)

NiklasFalk 03-21-2015 04:25 AM


Originally Posted by guttedmiata (Post 1217144)
Doing all of this to only use 2nd gear. ;)

Some are more crazy dedicated than others :)

Downmented 02-14-2016 07:00 AM

Thread bump. To any of you that had issues with this, have they been resolved? If so how? Have you guys been in contact with v8r in regards to the issues and have they communicated any interest in implementing a fix in their current kits? Almost a year since the last post here which Is plenty of time to make fixes to the kit.

slmhofy 02-15-2016 09:47 PM


Originally Posted by Downmented (Post 1307614)
Thread bump. To any of you that had issues with this, have they been resolved? If so how? Have you guys been in contact with v8r in regards to the issues and have they communicated any interest in implementing a fix in their current kits? Almost a year since the last post here which Is plenty of time to make fixes to the kit.

I guess not much to report on from my end.

Disclaimer: I got a super early kit (they didn't even have instructions yet) and I don't know if they are offering different parts yet. Also, everybody's car may have individual circumstances that could be different.

You should call them yourselves if you have any questions. And, as much as it may sound like I'm griping, V8Roadsters customer service is probably one of the best experiences with a company I've ever had.

Now that said; it's a great kit to get you most of the way there, but depending on your level of acceptance, you may spend some extra time making it work better.

I gave them my opinion with pictures to them of the issues I was having and they politely said I either had some pieces wrong or needed stiffer bushings. Whether or not anyone else provided them with feedback since then, I do not know.

I was seeing a ton of flex from the pinion of the diff even after I replaced the OM GM bushing with a poly bushing. When you loaded or unloaded the tranny hard in gear, it looked like the shifter was rowing a boat. And I was missing 1st to 2nd gear 50% of the time when shifting fast. In my opinion there is just too much leverage on that 1 front pinion bushing no matter how stiff a bushing(even a solid metal bushing). It needs to be securely mounted like the welded tab they use for the V8 cars that get rid of the PPF, or a bracket like I made. If you saw this in person, you would understand what I mean.

The bracket I made completely fixed the issue and I can't remember the last time I missed 2nd gear. It's better than the OEM setup. I think what causes people to miss 1-2 is the slop of everything moving from the engine mounts, down through the PPF to the diff mounts. The bracket I made adds a 3rd mounting point. So I have polly diff bushings, the bracket connecting the pinion to the ladder bar, and original motor mounts.

I opted for the aluminum drive shaft when they had the special when the kit first came out. It ended up being really out of balance, and V8Roadsters was great in helping me send it back in exchange for a regular steel one. It was only 2lbs heaver and didn't have any balance issue. 8Roadsters does not make these, they are from another company.

The bushings that came for the diff mount bracket are thin at the top which moves the whole diff futher up and causes the top of the PPF to hit the rear sub frame. I bent the top of the PPF down a little and glued on a hard rubber sheet to it which is basically sandwiched between it and the subframe. I showed this to them and they said I must have had something wrong. And even if it were further spaced down, the PPF would just hit it anyways under load when it flexed.

The Getrar diff kinda has a lot of slop in it and makes a little noise under certain conditions like slow speeds/parking lots when fuel overrun kicks in and CL idle kicks the fuel back in. Other than that, you never notice the slop. It also whines around 50mph, but that's the only time it does.

You'll need to re calibrate the speedo pulse width somehow, but I haven't gotten around to it yet. 60 indicated is around 72mph and 70 indicated is ~85 with 15x8s.

That's most of all I can think of right now. I've got probably between 5-10k miles on it so far. The gearing is absolutely wonderful for a street car with at least 250whp. I've even got my boost down to 12psi right now, so maybe 200whp and yeah it's doesn't pull through the gears as fast, but it's still great. 1st to 2nd is a little big. Under full throttle, mine drops from 7400 to 4800.

Anyways, sorry for the essay. Curious to see what the other members who have the kit have to report.

Dietcoke 02-17-2016 12:16 AM


Originally Posted by Downmented (Post 1307614)
Thread bump. To any of you that had issues with this, have they been resolved? If so how? Have you guys been in contact with v8r in regards to the issues and have they communicated any interest in implementing a fix in their current kits? Almost a year since the last post here which Is plenty of time to make fixes to the kit.

Zero issues with my kit, don't use the PPF though (v8). Did have to add 2 feet of hose to the breather cap to keep the diff from puking, there is a TSB out on that from cadillac. Cars with less power may not have an issue, the exocet is pretty retarded at 404hp/1650lbs

Chilicharger665 02-17-2016 01:53 AM


Originally Posted by Dietcoke (Post 1308418)
Zero issues with my kit, don't use the PPF though (v8). Did have to add 2 feet of hose to the breather cap to keep the diff from puking, there is a TSB out on that from cadillac. Cars with less power may not have an issue, the exocet is pretty retarded at 404hp/1650lbs

Build thread? I don't want to scroll through FB shit.

Dietcoke 02-17-2016 06:38 PM

FB would be quicker.

V8 Exocet #134, Manhattan KS | MEV OWNERS GROUP - A top kitcar forum for kit car builders

EO2K 02-17-2016 08:11 PM


Originally Posted by Chilicharger665 (Post 1308426)
Build thread? I don't want to scroll through FB shit.

Quoted and prop'd. :likecat:

Alternative 03-04-2017 10:55 AM

Does anyone have details on the template provided by V8R? Getting them to actually ship me all of the pieces has been like pulling teeth and they have not responded to my requests for the template.

Alternative 03-06-2017 12:52 PM

https://cimg0.ibsrv.net/gimg/www.mia...a90cf0e9b4.jpg

Is this the same "template" everyone else was given?

Are you really required to cut away the captive nut mounts? Has anyone had success using this kit or has everyone been required to build their own solution?

Rexpelagi 05-12-2017 11:19 AM

3 Attachment(s)
Bump / just checking in - I just 'finished' the swap in my MSM. I really like the gear ratio change, but there is A LOT of clunking. My differential had 98k on it, so it could be partly that, but I'm not sure yet - need to do some diagnostic work. I'm also going to get underneath and verify my axles are fully seated - they went in and clicked but I'm not sure...

My preemptive slop solution:

Attachment 180887

Axles (EDIT: I confirmed with V8R that there should be 0.25-0.375" exposed, so this appears to be correct - leaving pictures for additional reference):

Attachment 180888

​​​​​​​Attachment 180889

Alternative 05-12-2017 11:25 AM

I am experiencing the same exact problems.... the mount pushes the PPF against the rear subframe, the driveshaft also can contact the PPF and the fill plug hits the exhaust.

Rexpelagi 05-12-2017 11:33 AM


Originally Posted by Alternative (Post 1397071)
https://cimg0.ibsrv.net/gimg/www.mia...a90cf0e9b4.jpg

Is this the same "template" everyone else was given?

Are you really required to cut away the captive nut mounts? Has anyone had success using this kit or has everyone been required to build their own solution?

I completely forgot they supply a template until after I cut it on my own. I never went back to look for a template, but that doesn't look like what I cut though?

Alternative 05-12-2017 12:06 PM

I had to twist an arm and a leg to get them to actually send me a template.

It appers as if you cut away one of the mounting points for the PPF.

Rexpelagi 05-12-2017 06:30 PM


Originally Posted by Alternative (Post 1413718)
I had to twist an arm and a leg to get them to actually send me a template.

It appers as if you cut away one of the mounting points for the PPF.

I actually wasn't supplied a bolt for that, and the stock bolts are way too long, so I assumed just the back hole was necessary. I see now that the adapter is threaded, and I still have 3/4 of a hole, so I can throw another bolt in there. With the front bracing I made though the diff is pretty secure.

Here's a video of the noise I'm getting. My conclusion right now is that it is just noise within the diff itself (the noise occurs whenever I take up slack in the diff - aka, engage the clutch).


Alternative 05-12-2017 07:53 PM

It looks like the driveshaft is binding the way it is skipping.


All times are GMT -4. The time now is 11:22 PM.


© 2024 MH Sub I, LLC dba Internet Brands