Hey Paul, I am the guy who bought your turbo, remember? What's up?

I will have Jim Labs cradle in my car come this May when I return home from school in FL. I have everything but axles for the swap. Can't wait to get this rearend put in so I can start cutting some nice 60ft times.......

 

I remember, How are things working out? I can see from your sig that you are liking the setup. Good luck with the rest of your project.

BTW I ran a best of 11.4@ 123mph with that setup at 14.5psi with a street port motor.

 

So what you are saying is that it is cool for JIM to place his opinion on a product and or service and you call it "BENEFICIAL" to the community!

I completely disagree.... everybody has an opinion and why should I or anybody hold his opinion HIGHER then the next guys?

Yes, Jim has contributed tons to this community but that does not make him the Judge and Jurry when it comes to all other options for our cars. No one person can decide what is good and what is not or how much too charge for it.

Enough said!

 

Eh?

His first post said the same thing my last post did. That the only point of this is to eliminate the torque arm, and there may be simpler ways to do it, but at least this is an option. I may have been more polite in the way I said it, but it's still the same statement.

I never said I was holding his opinion higher then yours, or implied it was any better then yours (actually I think most people's opinions are pretty much worthless, including my own, however observations of facts are an entirely different matter, and more along the lines of my intent in the post you quoted).

 

I don't mean too be testy but some people know how to strike a nerve.

I think the more options the better for everybody so lets leave it at that.

 

Jim is correct to an extent, but the fact of the matter is that neither this setup, not the Cobra IRS setup is "bullet proof." We all know this. I have purchase Paul's setup for the following reasons:

1) because it has been tested and beat to hell at that
2) because it requires essentialy no fab work on my end
3 because it eliminates the torque arm and hold the front end of the diff still (with bushings).
4)Because I already own an upgraded diff and 300M axles
5)Most Importantly, this setup will eliminate wheel hop without increasing NVH.

If you can eliminate wheel hop you can greatly reduce rear end shock, which is the #1 cause of diff casing failure. By holding the diff and tranny in place you allow engine torque to be smoothly transmitted through the driveline instead or bucked and jolted through in winding phases.

I also believe that the external torquing of the casing through transmission movement is a huge problem. It is interesting that I have yet to hear of a V8 swapped FD breaking a diff casing. Perhaps this is because the T56 utilizes a tranny mount, and because the LS1 motor mount setup allows less play than the FD setup.

Think about it.. Why aren't V8 RX-7 laying down **** loads more torque than their rotary counterparts breaking diffs?

I see the lack of front bushings as a weakness of the Cobra design and I am skeptical about its strength. Jim, how can you conclusively say that the Cobra IRS is stronger when sufficient testing has not yet been conducted. I also read about a structural failure due to a design flaw in one of your first units, though I'm sure this has been corrected in the current design? I commend you on your efforts, I am just waiting for more test data before I can openly accept it as a superior option. I'm sure you can understand that.

As you know, I am in complete agreement that the weak stub shafts and casing are the weaknesses of the Mazda unit, but I have no doubt that this IRS configuration will hold 600RWT as Paul said.

Solid diff bushings are not a viable option for me due to VNH.

For those of you with goals upwards of 800-1000RWTQ, you probably won't want to use either of these options. However, both options are sufficient for my short-term power goals.

Cheers to both of you for giving us options.

 

Because they don't have to launch at 6,500+ RPM to be in their powerband.

Because they're used in 700+ RWHP Cobra Mustangs which weigh another thousand pounds more than a 3rd gen. RX-7.

Or, these pictures might help...







Someone managed to bend the front tube at the exhaust notch by ~1/4". Abusing the car by doing clutch kicks on the way to the grocery store, er, race track will do that.

Yep. No more exhaust notch.

Look for posts by LS1-FD at Torque Central.

1993 RX7
402 ls2/t56
507rwhp
609rwhp 100 shot no times yet
7.1@107mph
10.5@136mph NA 427
10.7@142mph 75 shot 402

 

Mike (LS1-FD aka Mas280) ran all those times in his sig with a stock 4:10 Torsen FD LSD setup.

We'll see how the Cobra setup works with his new motor. Should make close to 600rwhp n/a and some nitrous for giggles. Should be one fast bad ****.

 

I found LS1-FD's car on torque central, and he seems to have modified Jim's Cobra subframe as well or maybe it is his own creation, seems to be a trend! Here are a few pics I copied.......

Jim does this look like yours??????????????????????????????????????????

 

A trend of two?

It looks like he added rubber bushings to isolate the rear of the differential from the subframe, the same as Chris Heiser did (see below). Heiser bought a set of aftermarket gears despite my recommendation to use only Ford Motorsport gear sets and so his gear whine was unlivable. So the changes are due to noise concerns, not a structural concern, but thanks for posting the pictures anyway.





I have nothing to hide here. I didn't make a cent off the Cobra cradles, and in fact, covered some of the cost of powdercoating half of the last run out of my own pocket because I'd underestimated and that's not the buyer's fault.

Unlike you, I only charged ~$450 for the complete conversion kit, including hardware, which was the cost of production based on materials and hourly rate. In addition, I let people go directly to the Driveshaft Shop for axles to eliminate the middle man and avoid any delay or cost increase.

Maybe I should take a lesson from the book you and Hinson seem to have read and charge $2,000 for the next modification I come up with?

 

That's news to me. I thought I saw a post stating that he'd been to the track with the Cobra IRS. Looks like I misread; he's been to the track track with the Cobra IRS, but not the drag strip. The power levels are still valid, however, and I have no concerns about him drag racing with the setup.

http://www.torquecentral.com/showpos...08&postcount=3

FWIW, Chris Heiser hasn't installed anything on his car without having some sort of problem associated, so I wouldn't be the least surprised if he stacked the bushings for the differential incorrectly and raised the pinion angle himself. Pinion angle was set to the FD pinion angle and I have no control over how Hinson's transmission mount positions the driveshaft... or user error.

BTW Mark, how's your LS7 coming? I thought I saw a post saying you were going to be picking it up a week or two ago.

 

Those two are the only two currently being used with a V8 swap, and both are not using your design. Thanks for bringing that UP.

BTW JIM, I hope you feel like a good person now after posting your cost but you still don't have a clue what it is costing me. I am sure you will be waiting for the feedbacks from my rear subframe mod.

Another thing................. never compare me with Hinson!

 

No, they're not. Even based on Torque Central posts alone your count is low.

Not strictly as delivered, but that's their choice; they own the parts.

Does that bother you for some reason, because it certainly doesn't bother me.

The next thing I bring UP will be your obvious lack of intelligence.

$1,000 is a lot just to weld in a couple bars and a mounting plate. Typically people could expect to get an entire roll cage for that kind of money. The fringe benefit being that a roll cage actually serves a purpose...

Not really. It doesn't do anything that the stock PPF, a torque arm, or any other type of differential brace would do.

 

Jim, I give up with you.......... I am too old and too busy to argue with your bullshit. Have fun bugging somone else.

You know who made me realize that this has just become childish, my wife. She also said you may be smart but you have alot of growing up too do.

 

Sure you are. Besides, you can't argue with the truth about your own modification and you've run out of mud to sling about mine.

Oh no, not that!

 

Did she tell you that taking a parting shot while saying you're not going to argue any longer is pretty childish too?

 

That's why I deleted it, if you didn't notice.

 

Can we leave it alone now? At the end of the day people will choose what option they want for their own reasons including cost

 

Can we leave it alone now? At the end of the day people will choose what option they want for their own reasons including cost

 

No, you changed it (refer to the bold text in my last post if your memory is faulty), and still took a parting shot at me...

 

I guess not

 

Hi Noob. Are you starving for attention?

 

Lol Hi old timer.
No not really, I just think it's a shame when a thread degenerates this far.
And being a noob I'm still very impressionable

BTW loved some of your very informative posts, inspiring.

 

Actually, the more they debate the more I learn.

 

I'm all for a technical debate but personally I could do without all the personal embellishments.