Elfords big brother

[Th0m4s]

I wonder if that really is the company which produced the seats...

I might have found some nice wheels for my car but I'm not 100% sure they will fit. The rims are some old 13 inch Enkei Apache V. They would need some work but I can get them cheap and they have the 4x110 bolt pattern. What I'm not sure about are the rear disk brakes.



This is how my rear disk brakes look like. I never really looked at them before because they are more or less new. Just to be sure: Do these look like the normal 4x110 rear disk brakes? Which diameter should they have?
I've read and asked much about fitting 13 inch wheels on RX7s with rear disk brakes and they seem to fit as long as it's no GSL-SE because they had bigger rotors.

By the way the Enkei wheels have a bit of a strange offset. In the front they are 13 inch 6,5j +12 and the rear wheels are 13 inch 7j +5. I've measured everything on my RX7 and I think they should fit. It's a very close fit but it should work.

This would be the design of the wheels:

[spirit r]

I might have found some nice wheels for my car but I'm not 100% sure they will fit. The rims are some old 13 inch Enkei Apache V. They would need some work but I can get them cheap and they have the 4x110 bolt pattern. What I'm not sure about are the rear disk brakes.

My first Rx7 built in 1981 with the rotary 13 inch 4x110 wheel and 185/70/13 tires was without vented disc on the rear. Vented disc only on the front. Can you measure the diameter of the disc?

Thomas

[TOOL]

The wheel offsets are fine. Don't worry about that.

Those are not standard 4x110 rear brakes. S2 disc brakes weren't vented.

You'll have to measure them.

Or find better wheels in a 15 inch with more width too. 8J rear will fit with the right offset.

[Th0m4s]

Now I got curious about the brakes and took one rear brake apart today. This is what I found:





The disks have a diameter of 257mm. The wheel bolt holes are drilled out a bit more to towards the middle so I guess the disks originally came out of a car which has a PCD of 114.3mm. The hub hole has a diameter of round about 65mm. I only had a yard stick so I couldn't measure 100% exactly. It looks like the middle part of an original brake disk is sticking inside the bigger disk. I guess the disk comes out of an other japanese car but which car could that be? It must be an 80s car, too. Might that even be GSL-SE disks?
Which diameter do the original unvented disks have?

[TOOL]

They are S3 rear discs by the looks. Same as GSL-SE.

All the dimensional details are available here:

http://brakeparts.co.uk/#!/shop/MAZDA/R ... nd%20Drums

To answer your question though, solid S2 rear discs are 236mmx10mm.

[Th0m4s]

Many good news and a question today:
After adjusting the choke mechanism and installing a 4.7 ohm resistor in line with the electrical choke actuator to slow it down a bit my car starts everytime like it should.
I also found somebody from the TÜV who is willing to accept SSR wheels on my car. Last week I found a set of 4 14 inch SSR formula mesh wheels with the 4x110 bolt pattern in Japan. They even have nearly the same offset as my old wheels so that shouldn't be an issue.
They look like these:


Next month I'm going to disassemble the RX to get it painted. The car has rust on the bottom of the doors and at the rear and I don't want to wait till it gets worse. The new color will be black with bright light blue Mazda advertisements in the style of the 80s. I want to paint the center of the new rims in the same color.

Also a week or so ago I had some issues with too much fuel. I fixed that today. The RX7 has an additional early kind of injector injecting fuel right in front of the Turbo over 5500rpm and 7psi of boost. I guess the car was set up for much lower octane fuel and needed the injector back in the 80s but now I'm driving it with 100 octane fuel and cold BR9-EQ spark plugs. I simply disabled that injector today and the air fuel ratio my wideband shows seems really good to me. At 12 psi I get round about AFR 10.8 and the car is pulling much stronger than before without any bogging.

Now I've got a question: When accelerating under full boost my exhaust temperatures in front of the turbo climb up to 900°C. Does that sound about right to you? It would be interesting for me to know what the Elford turbos are doing there if anybody ever measured that.

[KiwiDave]

Those are great looking wheels. Good work too finding a tame TUV engineer.

Your exhaust temps are ok. A 12a PP motor will typically have full throttle exhaust temps of 900-1100 degC. A Renesis motor runs at 880 deg C.

This is why cheap mufflers don't go the distance with a rotary engine. Exhaust temps are more than enough to melt fiberglass packing in very short order.

[TOOL]

Nice. What's the widths and offsets?

[Th0m4s]

6 and 6.5 and the offsets are +15 and +20. That should work because the rear wheels are standing a bit more out because of the bigger brake. My wheels at the moment are 6.0 all around and the offset is +18 in the front and +22 in the rear.

Good to hear the exhaust gas temperatures are ok. I guess that means I need a better egt gauge. My VDO gauge only shows temperatures up to 900°C. I will need an old looking gauge which is able to show a bit more. If you know any good looking egt gauges please tell me...

[TOOL]

Yes, those wheels will be pretty mild.

Good score finding them. I like SSR mesh (obviously).