Messages

There was a time when I would be in the pub by now on a Friday, but now I\'m looking at rotor housing geometry!

So as far as I can see, my map has the latest firing position on the leading plugs at 0 degrees. This puts the rotor chamber centrally about the plug centreline on the rotor I want to fire. That is half way between the two plugs. Therefore the apex seal on the other rotor must be exactly half way between the two plugs. Therefore the maximum delay on multi sparc cannot be any more than half the number of degrees (at the rotor, not e shaft) between the plugs. I\'m not sure what that is, but its not much.

So if you are going to do this, you really need to disable multi sparc in areas of the map where there is very late timing, because I don\'t think that you have time to get more that one spark in.

I am thinking of a more conventional approach. Why not run the leading plugs on a two channel capacitor discharge system? It would be best to add the logic two split the two plugs, and only fire on the appropriate cycle. That way you double the capacitor charge time available, and I know from experience that this will help prevent misfiring the plug at high RPM where you don\'t get enough charge time.

BTW, how were you thinking of identifying which leading plug to fire?


Keith

Sounds similar to mine too. I had a very small leak in the coolant hose on the rear plate. I think that what was happening was that as the engine warmed up, the leak did not let much coolant past, so coolant was pushed out to the expansion bottle. Then when it cooled, air was pulled back into the engine through the slight leak instead of pulling back from the expansion bottle, leaving the expansion bottle too full. Water doesn\'t get through small holes as easily as air. So after a few warm up/cooldown cycles, the coolant would drop in the engine, but overflow in the expansion tank.

I changed the hose and it was fine for the next 18 months, barely ever needing a top up.

Keith

Presumable this is with a PFC. I ran my single fairly lean around idle, which meant I needed much more accelerate injector. On settings 2 in the datalogit I had:

RPM       Amount       Decay
5000      7.5000        1.000
4000      7.5000        1.000
3000      8.5000        1.500
2000      14.500         4.500
1000      11.500         3.500



That fixed my light throttle problems.


Keith

Bob
Try Tim at RX motors. Mine was not too expensive. Pig of a job with twin turbos though, so be sure that it is the OMP thats caused it!

Keith

I used a Saxo pump on my FD. I used a relay and wired the pump back to the battery via a new fuse box.

Buy a big relay - the pump will take quite a current on full steering lock. I think my relay was rated at 40 amps. The pump will blow 20 amp fuses after a short time as a guide.

I used a live feed from the igniter to trigger the relay. It can be found at the condenser, by the ABS valve block. I took the earth via a switch inside the car so that you can turn the power steering off. Whilst you would never want it turned off while driving, I left it turned off while I warmed the car up and let it cool before stopping the engine. But then I have a small odyssey battery.....


Keith

I seem to remember that there is a 10mm nut or bolt right at the top of the box which is hard to see. I spend a while pulling the box and wondering why it wouldn\'t move!

I\'m not sure whether all RX8 6 speed gearboxes are the same. Mine was an ebay find from a crashed car. A bit of googling will get you the ratio\'s - they seem to be closer than the FD box because they have a direct 5th.

I have an OS Giken twin plate clutch, which comes with a new flywheel. None of this has been assembled yet so there are probably still some unknowns.

The car was my daily driver until I converted it to single turbo about 2 years ago. Its now stripped to a shell for a rebuild, where I want to lose as much weight from it as I can. I plan on it being used on the road mostly, and maybe on the strip or track days for some fun.

Keith

I\'m trying to get one to fit in now - most of the problems have already been mentioned -

Power plant frame needs modifying. To get it to fit the box doesn\'t look too hard. To get it to fit at the right height so that the gearbox and engine stay at the same angle needs a bit more work. This means that all the engine pipework still fits and the prop angle is correct.

Clutch - needs a push type, but available off the shelf

Starter - the FD starter fits the bellhousing if you make up a 6mm spacer, although I haven\'t actually turned the engine over with it yet. That\'s mainly because Tim has the engine!

Gearlever - its a bit further forward. My dashboard is now in the loft!

Clutch slave nowhere near fits allthough a FC one might be modified to fit.

FD Prop looks like it might fit at a quick measure, but I have not tried it yet

The RX8 gearbox doesn\'t have as many electrical senders. It appears just to be speed and reverse lights. The FD has a neutral switch. I don\'t anticipate this being to much trouble for the PFC.


Those are the things that come to mind. There might be more as I get further into it.

Keith

Many thanks. That\'s not where I need to modify it so I should be safe. I\'ll see whether I can add some strength there while I\'ve got the tools out!


Keith

Chaps
I have spent the afternoon measuring the mounting bolt positions on the FD and RX8 gearboxes, in readiness to modify the PPF. To make it all fit while maintaining the angle of the gearbox in the car means that I need to cut the PPF and re-weld it in the right place. I\'m a little concerned about weakening it.

Now my question is, those of you who have broken a PPF - where did it break?




Rgds
Keith

Marks description sounds like mine when it broke a while back. If you have the stock ECU, it might be in limp home mode. Mine behaved in a similar fashion when the OMP failed. In limp home mode it runs fine up until just before boost, when the engine just cuts out.
I think that you need to wire an LED to the diagnostic plug to read the ECU fault code.

Rgds
Keith

The PFC will flash the dash light at 60 as a warning. I\'ve just checked my last datalogit log, it peaked at 20.
Some people have reported readings well over 100 without engine damage. There seems to be an opinion that the knock sensors can lie, but mine seems to give reading that align with changes to the ignition timing. When I have had slightly high readings, a couple of degrees out of the timing in that cell often brings the knock down.

Keith

Mine starts up at 11\'s, but leans off when warm. Against common opinion, mine would happily idle at 14.3 without misfiring when warm. It was a big single with stock 550 primary injectors and stock porting. If you didn\'t mind an occasional misfire, it would go leaner - 14.6 was possible.

Two points:

1) If you get it that lean, you need to add a lot of throttle enrichment to get it to come off idle cleanly. You need something like double the default pfc values at 1000rpm

2) I found it impossible to reduce the fuel past a certain point. This didn\'t cause a problem at idle for me, but on the over-run I was getting 11\'s when I wanted 13\'s in the lower cells. Reducing fuel in the appropriate cell didn\'t make any difference. It seems to hit a minimum at about 1.5-1.8 mS (I can\'t remember the exact value).After that, reducing the number makes no difference.
I added a lot to the lag time to the injector settings  (- 0.5). You this leans it a little, so you need to correct all cells in the map by adding 0.5mS. This will take you back to about where you started but will allow you to reduce the minimum injector time by 0.5mS from the previous minimum.


Other than that, check the fuel pressure!

Keith

I\'ve had the Zeitronix for about 2 years with no trouble at all.

Keith

I use the Zeitronix zt-2 with good results. It also has the capability of logging data from the widenband plus EGT, RPM, throttle position and boost to your laptop. They do a few packages with various guage and display options.

http://www.zeitronix.com/