www.RX7fb.com

The nice thing about this is that it looks like a very neat professional installation... not the usual untidy lash up sometimes produced by owners trying to mod their cars... from the set out of the coils to the radiator, we can see the thought and care that's gone into it... it's a credit to you Steve.
How's the car shaking down now that you can put some miles on it?
What differences have you noticed in terms of fuel consumption, engine pickup / throttle response, cold starting, hot starting etc, etc?
( or do you need to get it on a rolling road before you can sort of optimise it)
Fantastic, inspiration work on this car.... you've turned it into something very special....

Thanks again guys.

I think the photos make it look tidier than it is Ian! But yes I've spent a fair amount of time trying to think about where everything will go and not rushing too much so it doesn't have a lashed-up feel to it.

I've put about 300 miles on her now, and she's running quite well. The fuel consumption is currently matching my stock set-up around town, which I'm quite pleased with seeing as I'm not longer using the primary/secondary system which will hurt the economy. I've not taken her on a long enough A roads and motorway drive yet where I've not been working on the map (lots of accelerating and driving in the wrong gears to reach all areas of the map) to know whether I've gained any extra urban economy.

The pickup from idle and throttle response has definitely improved, I think lots of this is down to the ignition mapping. Looking at the maps used in FCs and FDs the increase in advance is not linear like a dizzy provides and applying that same shape to my map has definitely improved the response below 3k rpm. Likewise on the timing, adding some more advance above 5k rpm seems to have it rushing to the redline harder. When I get on the dyno I'm going to mostly be tuning the ignition map and intended to get some back to back printouts with my electronic tunes ignition map vs what the dizzy provides.

The fuelling at the moment isn't perfect. On the whole its better than the carb at providing the right AFR across diverse loads, but there are moments where the map isn't quite right yet and it will spike lean or rich. Poorly tuned EFI tends to feel much more 'lumpy' and likely to kangaroo where as a poorly tuned carb often just feels a bit 'flat'. I've spent a bit of time working on my acceleration enrichments recently which is helping lots, but I really need more time with a wingman to work the laptop for me to finely tune them, so I might end up doing that on the dyno.

Starting is OK but not great at the moment, it always started but might take 3-5 second to catch. The starting algorithm takes into account the main fuel table so I'm waiting till thats set in stone before I get to worried about fine tuning the start up.

The one thing that's a bit frustrating right now is the idling. Most of the time it idles fine, just every now and them the revs drop to fast and it doesn't catch itself. When I get chance I'm going to triple check my throttle balancing so it's not trying to idle on one rotor, and I think I need to adjust the timing and fuelling so it starts to slow down the rev drop before it comes into the idle zone.

So yeh now the Megasquirt is installed there's always some small part of the mapping that be be adjusted and made just fractionally better, the key is working out when to say enough is enough!

AS I've said on a couple of other places where I post about Rexanne, for now this is her 'finished'. I just want to drive and enjoy her for a while now. There's always going ot be maintenance to do and when the weather warms I need a second shot at the paintwork on the drivers rear quarter but on the whole I'm not going to be starting any major projects for a while*


*not unless I find the right GT Junior.....

Great reading and photos as usual. I too look forwards to playing with EFI but for now mucking about with needles will do me fine....


(that needles bit sounds wrong eh...)

I took the rx down the Brean Sands on Sunday for one of the retro rides meets, I would've posted up on here but I didnt realy decide if I was going till Sunday morning so it was a bit late for a thread.





It was alright, few cool cars lots of rusty scene cars. The weather was awesome though and generally the rx ran well.

I've had my laptop with me constantly and I've been slowly working out the niggles with the EFI. I've spent lots of time working on the acceleration enrichments and the throttle transitions are much smoother now. With the car driving smoother I moved on to working on efficiency of the cruise map. I'm running it a little on the lean side ( ~15.8:1 AFR) and have advance the timing a little to compensate and the pay off was 33 mpg average on the trip to the beach and back according to the clocks! GPS says my clocks over read by 10%, even so 30 mpg is a considerable improvement over the carb. I was being a god boy and sticking to 70 by GPS on the motorway and generally not thrashing but still I'm pretty happy with that.

In the process I killed the idleby leaning it out too much though, so sorting the idle and the starting thats still not as brisk as I'd like is next on the list. One mechanical problem I've been suffering with is heat soak on the intake air temp sensor. I made up a new bracket so the sensor is more directly in the air flow.



The heat soak issue isn't so bad now, but I'm still seeing intake temps of ~25 degrees above ambient, so I think I need a cold air feed to the throttle bodies!

Cheers Will.

Yeah cold air feed is on the to do list. May have bigger fish to fry right now though

Since getting the megasquirt up and running its never started as well as it did on carbs. I put it down to not using the primary/secondary system and just poor tuning. Recently the hot starts been becoming more troublesome though and in fact a couple of times it's taken me a good 5 mins to get it started back up again after a fuel stop / stall.

Either way, in the past couple of weeks it's started burning oil too. I premix and the OMP is removed so for the last 8 months of daily driving I've checked the oil level every couple of weeks and it's never dropped. I checked earlier this week and suddenly it was pretty much on the low mark. Filled it up and checked it again today, I've lost about 5mm on the dip stick in 100 miles.

So I bit the bullet and did a compression test. Only a piston tester but gives me a ball park idea. With engine hot, throttle wide and engine spinning at 260rpm (according to megasquirt) it made ~55psi on both rotors.

Thats not good is it? I think this 12a done ok, 85,000 miles over 28 years and as far as I can tell its not been rebuilt, but it's probably on its last legs.

I guess maybe it's time to sort a replacement 12a for the short term and to strip this one down and go wild with the die grinder.

Begging for a 12AT

Bad news man, sure whatever happens it'll be fixed by Monday though.

Haha. I dunno about Monday. Hopefully wont take too long to sort though.

I know 12at would be lovely Tool, but my wallet says no for now Would be a shame to loose the throttle bodies anyway, because I'm really enjoying how they make it feel.

Well it wasn't fixed by monday. No engines on the horizon right now I had some very kind offers of a loan engine, but it's not something I feel comfy with.

Having no car is crippling me, there's many times where just a motorbike isn't gonna cut it. Taking camera gear and lights to shoots for example!

That Micra turned out to be made of filler and I ended up weighing it in. So this time I've done it properly and bought a Mazda. It's still RWD and 50/50 wieght balance but its got pistons





I'm quite happy with it though. It's on cheap eBay coilvers so is a bit lower and firmer than stock and came with a pair of 15x8 wheels so I'm gonna pick up another pair of cheap wheels, bodge a scrap yard splitter on the front and feel quite happy rocking this for a couple of months.

I forgot just how well these handle, it's more nimble and 'pointy' than the 7. Doesn't feel as good in wider corners though and obviously the 1.8 4 pot just doesn't compare......

I'm in the middle of doing the sills and arches on my mum's mx5 so once thats done it'll get the 12a out of the rx7 and see what it's like inside. Hopefully I'll have the rx7 back on the road in a couple of months.

Well at least you kept it Mazda.
And once Rexanne is sorted you can start rotorising this... you know you will