www.RX7fb.com

A7RXY wrote: ↑Sat Jul 14, 2018 9:48 pm

biznatch wrote: ↑Sat Jul 14, 2018 9:13 pm Last week's event definitely added some motivation to update my build thread and move things forward again. I would have liked to have had my FB back on the road in time for the event but it wasn't to be. It was great to go along, see some fantastic cars and meet some of the regular members here

Likewise, good luck.... Dibs

Was good to catch up Glen.

All looks pretty good aye bro! I'll have to keep an eye out on the rack conversion as it's on my to do list!

loads of projects there Glen... subframe swap is on my to do list too. That reminds me I need to post the PAS lines to you.

Hobbawobba wrote: ↑Sun Jul 15, 2018 4:56 pm All looks pretty good aye bro! I'll have to keep an eye out on the rack conversion as it's on my to do list!

Thanks Jesse,
Yeah from what i have read so far there seems there's a number of ways to go with the steering rack conversion when doing the FC subframe swap. Some of the options being:

1. Use the FC power assisted rack with the hydraulic pump. This would need a speed signal from somewhere? to reduce the powered assistance as speed increases. At the moment I'm not sure where that signal would be derived from on the FB so maybe this would just be 100% assisted at all speeds?
2. Use a manual FC rack
3. Use a powered FC rack and convert it to manual. This seems to be preferred over option 2 above, i'm not 100% sure why but maybe it has a better ratio?
4. Use an electrically assisted rack, such as Opel Corsa/Holden Barina. Shorten the rack length to suit and re-thread for FC rod ends. Apparently EAS is a common conversion for older cars and there are cheap and simple controllers readily available. Personally, I'd like to see a few successful examples on the FB before I'd be convinced to go down this route.

I'm sure there are other options too. I'm not sure if there is any particular method that that is considered to be the best but most of the threads I've read seem to opt for a depowered PAS rack. I'm keeping my options open at the moment and would be interested to hear which way you and Ian are thinking to go with it.

ian65 wrote: ↑Sun Jul 15, 2018 5:09 pm loads of projects there Glen... subframe swap is on my to do list too. That reminds me I need to post the PAS lines to you.

Thanks Ian. They could be needed If I manage to find a workaround for the speed sensor input I could reinstate the FC PAS, or accept it will have full assistance at all times.

I know that PAS on 1st gens uses a speed sensor built into the speedo and I think that FC's probably do as well. You could use it on full assistance or maybe you could introduce a valve to reduce the flow of power steering fluid through the lines ( a bit like the idea of a manual boost control valve ) ... it wouldn't be speed sensitive but you could set it according to how you are using the car.... might be a solution?

There were 2 different kinds of power steering in the FC.

Most FCs used vehicle speed sensing power steering
Some series 5 (but not series 4) models used engine speed/RPM based power steering - generally these were in N/A models in the US and Infini turbo models in Japan. It was an inferior (but simpler) setup.

There is a separate computer which controls hydraulic pressure from the pump via a valve. Getting this computer to work in a 1st gen might be tricky without the factory FC ECU as well as I'm sure they are designed to work together.

If you ditch the controller and have the valve running in low-assist mode all the time, I dare say it will be perfect in a light car like the 1st gen RX-7 and would be lighter than the factory steering anyway.

In terms of electric power steering, yes you can try to fix a Corsa power steering column. These are easy to find in the UK and even have aftermarket controllers for them. But having a good look under the dash, there's not a lot of room for it - the column has a big motor sitting on it.

The other option is to use an electric pump to replace the mechanical one. Many cars used these so-called EHPS (electric hydraulic power steering systems), some notable examples include the Mazda 3, Toyota MR2 and Holden/Vauxhall/Opel Astra. I got one of the latter ones. There are 3 generations of pumps. The first one has an inbuilt reservoir and is self-regulating. The greater the pressure requirements, the more it ramps up. No speed control required.

The pump from the Spyder has an inbuilt reservoir and has a speed controller. To get the speed controller working, you actually need to feed it a speed signal that matches the original car and the controller can understand. Otherwise it might be possible to get an aftermarket ECU to control duty vs road speed via a PWM controlled solid-state relay. That said, I know an owner of an FC with one of these and he runs the pump full-time and it's not a problem at all.

PS yeas ago Ian did a great writeup on how the 1st gen power steer works which is pretty similar to the FCs in application: http://www.ausrotary.com/viewtopic.php?t=211744

KYPREO wrote: ↑Mon Jul 16, 2018 2:19 am PS yeas ago Ian did a great writeup on how the 1st gen power steer works which is pretty similar to the FCs in application: http://www.ausrotary.com/viewtopic.php?t=211744

I’d forgotten I’d written that that was a good few years ago

KiwiDave wrote: ↑Tue Apr 12, 2016 11:43 pm Good stuff. I'm looking forward to your results with the modified nikki

I'm looking forward too and a little confused you want to go the 13B swap befor you test the modified nikki!