Just another LS Swap...Caution: Lotus content.

I finally got the tach to work!!! This comes under the category of “ you don’t know what you don’t know, until you find out that you don’t know it”!  I’ve done 2 previous LS swaps, both into Miatas, and all that was required for the tach was to connect the LS computer signal wire to the Miata tach signal wire. Easy peasy tach works perfectly. Did the same thing on the Lotus... no tach! No idea where to look for the problem, bad wires?, bad computer? Wrong connection? Turns out that what I didn’t  know, was that the computer doesn’t put out a strong enough signal to trigger an aftermarket tach. I added a “push up resistor” (didn’t even know that was a thing!) on the tach and poof!....the tach works!

This is one of the details that had to be dealt with in order to get the body to fit over the Miata suspension.  The lower perch of the stock Miata front spring is above the upper “A” arm. The Lotus fender and hood are too low for this to work, so I had to make the opening in the upper A-arms larger so that the springs can pass through them, giving me room to lower the upper spring mount. Here is a photo showing the  modification.

That is beautiful work.  Well done.  

If you get bored you can reshape the mesh for the vents to give them a 3rd dimension by shaping them around MDF.  A couple of ways to do it, but cut the shape you need from the center of a larger piece and route the edges of the male portion. The push, press, pound the female portion over the top of it with mesh material sandwiched in between.  It works a treat with stainless wire screen that needs more stiffness.

Regarding the miata subframes, do they mount level?  what I mean is the rear cage, does it mount level front to back or should it be slightly inclined one way or the other?  I've always wanted to swap miata bits into an MGB, but have never done that sort of thing before.

Thanks,

Brian

In reply to BrianC72gt :

Good idea with the mesh. I have enough left over to give it a try. I’ll post pics if I can get it to work. 

I mounted both front and rear subframes level. I just set them on the floor and built the frame to connect them. They appear to be level in the Miata. If there is any angle to them stock, it isn’t obvious to the naked eye. I’m sure that there are Miata guys on this forum, that know for sure.  Hopefully they will chime in if I’m wrong.

Began fabricating the side skirts.  I think the pink really sets off the yellow! Maybe I’ll go with a “My Little Pony” theme.

Making some progress on the side skirts. The fiberglass resin dissolves the pink foam, so I had to cover them with masking tape before the first layer of fiberglass. I used short strand fiberglass filler to rough out the basic shape and bondo to refine them and fit to the body. I still have to smooth out the surface for paint. Here are some  current pics:

Looks like fun! Nice job!

Door cards were a little tired looking and had overspray from two previous paint jobs, so I refreshed them with vinyl die. I’ve never used vinyl die before, so I have no idea how well it will hold up, but they look great now. Big improvement!!

More progress on the side skirts. Both sides are fitted to the body and in primer. Will paint body color soon, but another project is in the way.

I have been making progress, but nothing that warranted  photos.  Today I did get the “hidden” door popper switches mounted.

Hidden switch location is clever and perfect! Looks like a tricky spot to get them installed. I'm guessing a right angle drill was involved?

In reply to Mezzanine :

There is a vent slot in that location so some of the work was done for me. I did use an angle drill to open it up a bit. And I had to find switches small enough to fit in the void between the top and the window frame. The skin on my knuckles will eventually return!

I just saw that my Lotus made the magazine as “Internet Hot Rod of the Month”!

Thanks GRM!!!

I just saw that my Lotus made the magazine as “Internet Hot Rod of the Month”!

That's because it's Sofa King Awesome!!

After looking at the date of the original post, I know exactly how I missed this, but good Lord, how did I miss this?!

One of the things that happened almost by accident, but turned out better than expected was the hidden coils. The headers I found were designed to run up and forward to mount twin turbos. I knew that by running them up and back, i could really simplify my exhaust routing.  The consequence was that if I mounted the coils in the stock location, they would come too close to the headers. I built a bracket to mount them under the headers. That gets the coils pretty far from the heat of the headers while still using stock plug wires, and also removes all of the clutter from the top of the engine.

Hard to see in the photo...but where did the coils wind up?

 Yeah the photo just shows that they aren’t where they are supposed to be! 

This shot shows them a little better. You can’t see the coils because they are blocked by the fuel cell, but you can see the wires. The coils are mounted just inside the upper frame rail.

Nice solution! They should stay nice and cool there.

Thanks!

Like I said, I was pretty fortunate for the whole build, every time I had a challenge, the solution turned out better than my original plan.

Making some more progress on some finishing details. Covered the center console panels in vinyl. Mounted the power window switches, and mounted the shift and brake lever boots.

Also with the panels off the car, I was able to get the parking brake adjusted. It finally works!

Got the driver’s side windows in today. Big PITA!  I still have to connect the window motor, but the glass is binding in the frame because of the tight fit. Need to sort that before I connect the motor.

Sofa King said:

My weight estimate is between 1700 and 1800 lbs. I will scale it as soon as I can get my hands on scales. Stock horsepower on the LS6 is 405, but I have a slightly hotter cam, so I am expecting 430ish. That would be approximately 4.44 lbs per horse.

Factor in the weight of the driver and that’s liter bike territory.  Or better.  Not to mention the much flatter torque curve you’ll have.  Hope your reflexes are good.

I had missed this one also, love all of it.  I had to post a tip after seeing the side skirt construction.  When working with fiberglass resin and foam you can just paint the foam with exterior house paint to keep it from melting.  It has to be exterior paint, there is something extra in it for durability.

In reply to BrianC72gt :

According to a body shell dimension sheet in my NA Miata manual the rear subframe mounting points are 10 mm different, resulting in the front of the subframe tipping down.