Hey guys - I am Ric Joranlien from Boss Frog. We started building rollbars for Miatas back in 1991, and over the years have developed a variety of other performance and suspension products for Miatas. In the past few years we have developed a full set of kits to install the LS series engines into Miatas.

We built up a '99 with a stock LS1 and have been drag racing it the last couple summers. We are always willing to answer questions you have about our kits, and builds in general. We have our regular website at www.bossfrog.biz as well as a photobucket site of our project at
http://photobucket.com/bossfrog_stuff/LSX and a small LSX Miata forum at http://www.createforum.com/bossfrog.

 

Oh-yea, the big boys are here.

 

Welcome fabricators of Great Miata Fun!

 

Ric does nice work. I went to his shop to pick up my rollbar. He gave me the tour and even let me roll around under his car. The bar install went pretty good. The fit and finish on the bar is great.

Ric I would be willing to let my car be the guinea pig for you to build an NHRA certifiable cage. Just throwing it out there. It might be good advertisement when I run 9's.

 

Cages are a tough business. We built them for awhile, but it is tough to make a good bolt-in cage. Truth is, you get a much better product if you built it custom in place - the fit is much better.

 

On your steering shafts, do you add another knuckle in for more header clearance?

If so, please PM me a price for modification of my 1990 shaft.

 

we extend the stock knuckle about an inch for front mounted engines. no change required for rear mounted (hack the firewall) mounts.

 

Do you still run the hooker headers on the rear mount?

 

as far as I know, the same headers will work on either position. The trick is clearing the steering shaft, and that doesn't change with a 1" engine shift.

 

So what kind of money would I be looking at to cage my car?

 

price depends on what you want done. we did a weld-in spec Miata for about $1200

 

Hey! Nice to see you here. I'm beginnig the swap this week end. Starting by tearing my '90 to bare bones. I, HOWEVER, am using an LT instead of the LS. I know I'll have to make some adjustments using your swap kit (Headers, for one thing). I'll have to use an adapter kit for the T56. Can you advise me of any other changes I'll need to make? Thanks, Judge Tony

 

I am not entirely sure of the dimensional differences between the LT and LS series. I assume there would have to be some modifications for the mounts. We would be willing to assist in any way we can - just let us know how we can help.

 

Thanks for the input. Another poster, 5.7, advised to order your kit without motor mounts. I assume that is because LS and LT mounts are different. He's done the LT conversuon so I'm hoping he'll be willing to offer advise. I'll be worrying the hell outta you guys over the next few months....Thanks again....Judge Tony

 

I've been reading some threads from guys complaining about the fit quality of the BF kits and also the unadvertised need for core parts. I've got no problem with supplying a core but I'm concerned about the complaints about the proper fit of the parts. Please advise. Thanks

 

The only "core" we require is the steering joint, and that is because there is so many variations between model years. You send us the joint, we extend it for you and send it right back.

As for parts not fitting, we have had very little feedback from our customers about any fit problems. Nathan made a comment about our fit (as our most high profile customer), and I suspect others are simply repeating it. The kit that Nathan installed was one of our very first ones, and we adjusted for some welding shrink on the engine mount after that. We put a great deal of effort into making a well-designed product and try to be sure everything fits properly.

I believe the more important issue is the design of the kits. Our engine mount is made of heavy rectangular tubing and boxed plates for engine support, where as others use 1' bent tubing. The most important area of the engine mount is the cross member in the front, as it must sustain all the torque and twist of the engine. We use a heavy rectangular tube with large gussets here - others build it much lighter. Also, if you look at how our differential is supported and compare that to other kits... well there is just no comparison at all. Take a closer look at how the different kits are built, and choose the one that will hold up for the long run.

Ric

 

Thanks for the response. AsI've mentioned before, I'm using the LT instead of the LS. I know some changes will have to be made. I'm hoping others in here can help.....motor mounts, headers, alternator, starter, hood clearance for the carb, etc. As with any swap, I know adjustments will be necessiary bbut the basics from your kit should work. Any suggestions will be greatly appreciated. I hope to benefit from others experiences. Thanks again Ric. I'll being worrying the crap out of you over the next few months!

 

How do you route unrestricted exhaust around your engineered differential mount?

This is one of the fitment issues I'm sure the fellow poster is referring to (pictures pulled off M.net from a fellow swapper....Not Nathan)-

 

Random question, but what kind of metal do you use to make the frog arms and do only having spots of welds effect the strength?

I had a fabrication guy looking at the car for other reasons and the frog arms caught his eye.

 

Have your fabrication guy do a search on "intermittent fillet welds" he might learn something. I do a lot of fabricating at work and I would like to say that I am smart enough to decide what process I should use to weld each bead, but that does not make me a mechanical engineer.

As for that hole we are talking about putting a die grinder with a burr in that hole for 30 seconds to solve that issue. It shouldn't have came that way, but now BF knows about it and can correct the problem. I could have taken care of that problem in jr. high metals class. I am serious when I say if you are hung up on a problem like this forget about doing this swap and go back to stamp collecting as a hobby, because either you don't have the proper tools in your shop or you do not have the knowledge and skills.

 

MX, please check out my other posts. I'm using the LT with the BF kit. I hope you can offer the benefit of your experience and give me a "Heads Up" on things to be aware of. Thanks

 

We have not been able to identify why these diff kit holes don't fit on your car - have not heard of this issue on other installs, and they have fit every car we have mounted. Agreed you will have to ream out the holes to fit - sorry.

 

Regarding skip welding on the Frog Arms, we utilize TIG welding on rollbars and Frog Arms rather than MIG welding. TIG is like soldering, where the metal is preheated and the filler material is fed by hand. It results in smaller, stronger welds, but requires more skill and time. Since the welding process is slower, and the heat is controlled, we don't get near the heat warpage that a MIG process yields.

 

"How do you route unrestricted exhaust around your engineered differential mount?"

It is a tight fit to route the exhaust under the larger 8.8 CV. We used a pair of common "S" shaped exhaust fittings to get under the CV, then we flatten the pipes slightly at the bottom to gain more clearance. You can see picture on our photobucket site - link on the first post in this thread.

 

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