build diary
<< | show individual entries | >>April 16, 2004:
An interesting discovery as I look through my "instructions" - the GRM build photos.
They put the tank in backwards! While this places the pickups at the front of the tank and thus makes them more prone to starvation under acceleration, it should sit the tank down flatter and make it easier to tie down. I'll have to try that. Putting in a surge tank would prevent the possible starvation problems as well as my plumbing problems so that may still happen. Hmmm, so many options.
entry 235
April 19, 2004:
I'm not sure exactly why the GRM tank was installed with the pickups at the front.
It's easier to slip the tank into place but it offers no other packaging benefits - and there's the potential problem of fuel starvation under acceleration (and lots of fuel under braking). So I installed mine with the pickups at the back. A frame of 1/8" and 1/16" aluminum has the tank firmly secured in place with very little weight and a cash outlay of about $12. I'm happy with the way things turned out there.
I also changed the rear end. The super-strong GURU racing diff that was in my street Miata is now in the Seven. The reasoning is that I have to get a custom driveshaft made for the Seven, and I'd rather not discover (like the GRM guys did!) that the smaller, weaker 1.6 ring and pinion isn't up to the abuse the Seven is likely to dish out. My Miata, despite being twice the weight, has survived for years with a 1.6 rear and it's much cheaper to upgrade that car to the 1.8 with off-the-shelf parts should that become necessary. This has added 15 lbs to the weight of the rear end but it's probably worthwhile.
entry 236
The 1.6 viscous LSD (right) and the 1.8 Guru torque-sensing LSD.
entry 237
The weight difference of the two diffs - 56 lbs vs 71 lbs.
entry 238
Remember that Shoe Goo stiffening? Well, it didn't survive very long!
entry 239
When I installed the last diff, the frame was upside down.
Installing it in the correct orientation took a little creativity.
entry 240
The lower support for the fuel tank.
This is an aluminum U-shaped channel for lots of rigidity and light weight.
entry 241
The tank is in.
The upper straps are 1/16" aluminum.
entry 242
The fuel filter is installed.
The pump will be strapped just above it.
entry 243
April 20, 2004:
I had been concerned with the sizes of the fuel lines, given that the Miata runs on 5/16" and the tank has a 1/2" outlet.
It turns out that my fears were unfounded - the pump has a 1/2" inlet and we have the adaptors on the shelf at Flyin' Miata to make the outlet 5/16". That was resolved far more easily than I expected! I'm also going to use fuel hose to feed the engine instead of bending up hard lines. While manufacturers use the latter, I suspect it's not for performance reasons.
entry 244
April 21, 2004:
More fuel line work.
I needed about 18 feet of 5/16" line in total (9' for the feed and the same for the return) as well as maybe 18" of the 1/2". It's all looking pretty good.
To ensure that I don't have problems fitting the lines past the transmission, I've put another transmission and dummy engine in the car. It's impossible to get anything past the bottom of the tranny on the right side which is unfortunate. But I've worked out routing for everything that will keep the wires from chafing as well as keep them clear when the transmission is being removed or installed. I did decide to cut one of the rubber mounts for the rear of the transmission down by about 3/4" as it was putting the tail of the transmission too high.
entry 245
The nice thing about working at a performance shop.
I need fuel line, but I'm not sure how much. So I brought home 60 feet of it.
entry 246
The fuel line routing.
While the pump mounting looks a little cheesy, this does work quite well. We do the same thing on some of our turbo Miatas.
entry 247
Another dummy engine in place so I can do fuel line and wire routing and don't accidentally put the main power feed through the transmission, for example.
This time I've mounted some accessories.
entry 248
These cool little mounts are what I'm using for wire and hose management.
A 1/4" hole and they pop right in. A ziptie fits though. I can't ziptie right around the frame rail because there are often body panels riveted to the other side.
entry 249
April 22, 2004:
Not too much work done last night - I finished the last two fittings on the fuel tank.
The return line is now hooked up on top and the extra pickup has been plugged. Most of my time was spent working on getting my Cadillac ready for a trip to Vegas this weekend.
CMC appears to have dropped off the face of the earth. Their phone line no longer takes messages and emails are not being acknowledged. I could repair the broken/sawn nose cone that was shipped to me, rework the upper control arm and transmission tunnel cover that didn't fit and make my own cycle fender supports so I'm better off than the folks who are still waiting. One person just contacted me and says that their frame arrived on April 8th after being ordered in November! Steve at CMC seems like a good guy but he's having trouble keeping customers informed. Even just hiring a temp to cover the phones would go a long way towards keeping customers happy...
entry 250
April 27, 2004:
Yes, I had a good time in Vegas.
Thanks for asking. It appears that I may have made a mistake with my 1.6 automatic TPS. The signal is a 0-12v signal as opposed to the 0-5v one my ECU wants. Oh well.
Update: turns out I was mistaken about the TPS. It's okay.
Lester Seal is doing some interesting things with his build. He's moved the differential back and up, will hopefully be using a modified Miata Power Plant Frame and is working on a dry sump. He also reports that Leslie is back in the office and CMC is starting to return phone calls. Good!
entry 251
Lester Seal's modifed differential mount to move the diff up about 1.25" and back 2".
He's also modified the frame to fit the Miata Power Plant Frame.
entry 252
Lester's PPF.
I'm not sure there's room for a passenger anymore, but the PPF sure looks good.
entry 253
Another view of the PPF mount and the frame modifications.
entry 254
April 29, 2004:
Whoops.
I looks like I might have a problem. My steering is now set up with the rod ends above the steering knuckle. But when I set up the location of my steering rack, I believe I measured as if the stock ball joint was being used, and that hangs below the knuckle. The tie rods are visibly at the wrong angle and I suspect the current setup has massive amounts of bump steer. I'll have to do some measuring to determine is this is the case or not. Simply moving the rod end so that it's below the knuckle causes problems due to the extreme angle of the attachment - at least when the suspension is at full droop. Both the rod end angle and clearance of the knuckle are a problem here. I'll have to do some thinking about how best to resolve this. Going back to Miata ball joints and more normal rod ends would certainly work, but then I'd need new steering knuckles because the tapered hole has been drilled out. Raising the steering rack will also cause problems with the angle of the rod end. Sigh. I'll find a way to make this work. Hopefully without having to spend too much time machining the knuckle. I can see now that it would have been simple to just keep the factory ball joints and extend the tie rods. Not that I had any straight tie rods to extend! I'll try to get some photos soon of the problem.
I started test-fitting a few of the body panels last night. There are some extra bends needed (no big deal) and one of the panels needs a little tweaking to clear the neutral switch on the transmission. The switch protrudes just a little bit too far to be covered by a flat panel. They fit reasonably well, but not as well as I'd expect from a CNC plasma cutter - the patterns need some work. This has been true of every aluminum panel I've tried so far. Basically the angles aren't quite right or holes are offset. Nothing that's going to leave a visual mis-match so it's only an irritation when I'm assembling. While I certainly saved a lot of effort by buying the panels pre-cut, I probably would have obtained a better fit by cutting them myself.
Update: after a bit of perusal of the FK Bearing catalog, I found a high-misalignment version of the bearing I'm using. It'll give me an extra 7 degrees of rotation as well as being slightly longer - both of which are good. It's also going to clear the knuckle better due to a lip on the ball - and to top it all off, it's rated for 5,000 lbs greater axial load. The downside is that they're about $20 each, almost three times the price of my earlier choice. Part number HJMX7T if anyone's interested.
entry 255