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redgriff500

9,253 posts

146 months

[news] 
Sunday 22nd July 2012 quote quote all
papercup said:
then they closed the M6 and the A road alongside (which we were already on) was just a traffic jam of people coming off the M6. So we spent 45 minutes in traffic at walking pace or at a standstill. Water never got above 101, oil hit 105. No issues there, but by now the centre console is almost too hot to touch.

and it must be the gearbox; it has no way of cooling itself down.
That doesn't really make sense.

The only way the gearbox can generate heat is by the gears / shafts turning if you are moving slowly it can't generate much heat at all - even if it was hot from the M Way it would cool pretty quickly (certainly in 30 mins) once stationary.

Are you sure it isn't the heat from the engine / exhaust you're feeling ?

In my TVR exhaust heat can be horrific. My SC'd MX5 on a summer track day the box got so hot I couldn't touch the alloy gear knob and had to swap the OEM plastic one back on.


papercup

Original Poster:

2,231 posts

102 months

[news] 
Sunday 22nd July 2012 quote quote all
crazy about cars said:
wow... that could technically mean good MPG smile
Yesterday, mixed A and B roads with a bit of motorway, and 'enthusiastic' driving when I could; 191 miles to 46 litres. 19 mpg I have worked out. Pretty good, and better than with the LS2 I think.

I'd like to do a comparison of motorway-only driving with that new gearing. It will be pretty good I think.

papercup

Original Poster:

2,231 posts

102 months

[news] 
Sunday 22nd July 2012 quote quote all
liner33 said:
Can you wrap the trans tunnel with something to make it a little cooler for the passengers ??
Yes, I wish we had. The midbox was covered in reflective blanket, we should have done the whole tunnel. Another thing on the list!

tinker-27

830 posts

107 months

[news] 
Sunday 22nd July 2012 quote quote all
I don't think it's the gearbox getting that hot but just the hot air from the motor , the rx7 has a big tunnel that is high in the car and the exhausts run in it not under the floor like other cars , my monaro was like a oven in side ( no air con on) . Sat in traffic the gearbox generates no heat , I drove it last week and the engine is fantastic the best all round motor so far I think , no shunt , revs well and still lots of torque !! Just needs a couple of turbos !

papercup

Original Poster:

2,231 posts

102 months

[news] 
Monday 23rd July 2012 quote quote all
You and your turbos!

Having done around 400 miles this weekend around the Midlands and the Peak District I can safely say its probably fast enough for the road. In fact, its barking. Amazing, linear power from the motor; keeps pulling hard right to the top, and, unlike the LS2, its worth revving it.

The mapper agreed; he said it was the best LS engine he'd mapped yet. He said that mostly the LS engines have a great big wodge of torque, then run out of puff at the top, but this is the first that didn't. Rev limiter is set to 7000.

On the road; its nice to have a usable 1st gear again. This Viper diff has been the making of the car. With the old gear ratios I pulled away in 2nd and spent far too much time changing gear, they were way too short. Now its got long gears and has no trouble at all pulling them. Its faster because of that, and far nicer to drive.


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4packet

34 posts

109 months

[news] 
Monday 23rd July 2012 quote quote all
Our approach on the heat is to use the below self adhesive foil lined insulation product stuck to the underside of the tunnel. It's less than 5mm thick and available in the UK (I got it from Summit though)
http://www.designengineering.com/category/catalog/...

As well as that I picked up a roll of closed cell foam to line the tunnel and floor inside. It's very light and supposedly effective. This was sold as 6mm house floor insulation. May double up in key areas if space allows.



Not tried and tested yet, but I did a god deal of research on the subject.

papercup

Original Poster:

2,231 posts

102 months

[news] 
Monday 23rd July 2012 quote quote all
4packet said:
Our approach on the heat is to use the below self adhesive foil lined insulation product stuck to the underside of the tunnel. It's less than 5mm thick and available in the UK (I got it from Summit though)
http://www.designengineering.com/category/catalog/...

As well as that I picked up a roll of closed cell foam to line the tunnel and floor inside. It's very light and supposedly effective. This was sold as 6mm house floor insulation. May double up in key areas if space allows.



Not tried and tested yet, but I did a god deal of research on the subject.
Thanks, thats useful. Craig and I have already decided to coat the underside of the tunnel next, both his car and mine. I'll have my air-con working again by the end of today, so that will help as well. Not sure why it seemed to lose its gas in the time that Craig has had it, he never broke the circuit at all (and even took the front panel off and removed and re-fitted the engines through that, so as not to touch the aircon).

I have a good guy down here, better than the birmingham lot, and I think he's going to take it on as a bit of a project. To do what I tried to get the birmingham lot to do; go through the whole system with a fine tooth-comb and replace any of the original Mazda stuff thats 15 years old or more. Most of the parts of an aircon system are generic, you don't have to have the original Mazda stuff. The valve in the dashboard is our prime suspect for the leak, as everything in the engine bay (rad, fans, piping, valves) was brand new.

Onward and upward. It'll be nice to drive on the motorway with the windows up; after driving home from Birmingham yesterday I had tinnitus all night!

4packet

34 posts

109 months

[news] 
Monday 23rd July 2012 quote quote all
Has the gas definitely leaked out then? I had an issue on the Supra where the expansion valve was dumping too much refrigerant into the evaporator causing it to freeze up. This blockage would trip the pressure valve and cut the compressor until it thawed. New expansion valve did the trick. The guys in the States are reporting 2 types of expansion valve btw so take care when ordering. See a recent post by Halfspec(?)on norotors.

Edit: here is is http://www.norotors.com/index.php?topic=12654.0


Edited by 4packet on Monday 23 July 17:23

papercup

Original Poster:

2,231 posts

102 months

[news] 
Monday 23rd July 2012 quote quote all
4packet said:
Has the gas definitely leaked out then? I had an issue on the Supra where the expansion valve was dumping too much refrigerant into the evaporator causing it to freeze up. This blockage would trip the pressure valve and cut the compressor until it thawed. New expansion valve did the trick. The guys in the States are reporting 2 types of expansion valve btw so take care when ordering. See a recent post by Halfspec(?)on norotors.
I don't know yet, I'm going to see him this afternoon. Expansion valve is the thing we think may be screwing around.

I'll have a look on No Rotors when I know more.

cheers

A

Dr G

10,953 posts

125 months

[news] 
Monday 23rd July 2012 quote quote all
Once again I love the attention to detail and 'completeness' of the project, all very well shoving the V8 in but it's how usable the car is turning out that makes it stand head and shoulders above so many projects.

papercup

Original Poster:

2,231 posts

102 months

[news] 
Monday 30th July 2012 quote quote all
Front pads: Pagid RS4-2 (blue) E1903, AP Racing pad number: CP3894D51

papercup

Original Poster:

2,231 posts

102 months

[news] 
Monday 30th July 2012 quote quote all
Rear Pads: Hawk HP+

4packet

34 posts

109 months

[news] 
Wednesday 1st August 2012 quote quote all
Do those Pagids survive trackday abuse Andy? I looked up the heat range and was surprised(reassured) how low it was. Am likely to go Carbotech and wondering if the XP8's all round would be sufficient.

papercup

Original Poster:

2,231 posts

102 months

[news] 
Wednesday 1st August 2012 quote quote all
4packet said:
Do those Pagids survive trackday abuse Andy? I looked up the heat range and was surprised(reassured) how low it was. Am likely to go Carbotech and wondering if the XP8's all round would be sufficient.
I love the Pagids. They stand up to trackdays just fine. And they fit, unlike the Carbone Lorraines......

papercup

Original Poster:

2,231 posts

102 months

[news] 
Tuesday 28th August 2012 quote quote all
Time for an update, as its been a busy month.

Where to start? OK, air-con first. The compressor, which bear in mind was new last year and was literally used twice for journeys, has (we think) snapped its main shaft. No-one knows why. It was winter the last time it was working, and at some point I turned it on and it destroyed itself, and I didn't even notice. Fast forward to the engine swap and even though the whole thing was done without disturbing the aircon system, or breaking the seals on any of it, it doesn't spin up when you press the button. Its getting power and you can hear the clutch engage, but it doesn't spin.

  • EDITED TO ADD* The aircon guy (below) says that, when it was fitted, the compressor always seemed REALLY tight; it almost stalled the LS2 when it was switched on, and was ridiculously cold. So he thinks it was simply knackered from the get-go.
I'm now using Chilly Willys, and aircon specialist near me (Findon) and have basically said to them 'I need someone who specialises in aircon systems to take ownership of this; replace it all if you want but i am sodding sick to death of this yet I will NOT give up and will have working bd aircon if it kills me so take the car and take the whole system apart piece by piece and change it all for new but just make it work and test it for more than 20 sodding minutes like the last set of 'experts'....'.

I am hopeful; there are a few peeps there who seem like wizards and talk about aircon systems like i talk about servers. With that in mind I already have another new compressor (instead of ebay, I've used an actual AC Delco supplier from the US, who have also been the cheapest yet and get me things in 4 days) and, on special order from Mazda in Japan, a new expension valve and....oh, the radiator-looking thingy that lives in the dashboard with the expansion valve attached to it. I forgot what its called; it was weeks ago now. Mazda say 3-4 weeks for delivery. I also have another spare of both of those from Craig, and the one in my car. Another £800 (ish) for those three. Ho-hum. The piping (which is already above the standards needed for this sort of thing) will be flushed out, and a new dryer will be put in the wing. With the aircon rad (which also has a name, I'm tired this morning and have no brain apparently) was new when the LS2 went in, and the fans simply come on with the button. Thats pretty much it I think....I believe thats the entire system, right?

We shall see.

Oh, an RPM shift light has been fitted and turns the entire system off when the car hits 4000rpm, and switches it back on when it comes back down. Blair's idea, and works well; I had it turn the whole thing off so I could watch the light on the dash go out, and know it was being switched off.

Edited by papercup on Tuesday 28th August 10:12

_Batty_

12,178 posts

133 months

[news] 
Tuesday 28th August 2012 quote quote all
Really enjoy this thread. The effort you're putting into this Rex is epic, hope you get the final product you've wanted!

4packet

34 posts

109 months

[news] 
Tuesday 28th August 2012 quote quote all
Shame you're still suffering with the AC. Hope it gets resolved properly this time.

How was Rockingham? Think I saw some pics on FDUK.

papercup

Original Poster:

2,231 posts

102 months

[news] 
Tuesday 28th August 2012 quote quote all
Anyway, sod the aircon, whats it like after driving it for a month? The answer is....much better. I like driving it much more now; the gearing has been the making of it, and the mapping is much better as well. Starts on the button hot or cold, and is amusingly bad-tempered when its cold (wants revving to pull away, vibrates a lot, like it has a hangover and wants you to bugger off and annoy someone else). Its fine within a few minutes of driving (or let it warm up a little at tickover) and drives fine. Also, you can start it when its been sitting for an hour or so, when its between warm and hot, and its fine; it used to be a pig - hunting and trying to stall. Mapper guy Greg - recommended.

The engine is much better; linear, without the big wodge of torque and breathless afterwards, like the LS2 was. This cam is great. I have a usable 1st gear, and the rest are spaced well; it pulls them just fine. Anyone doing this conversion; make the effort to lose the Mazda diff. Its a different car now. Been to and from Birmingham a few times since (details to follow) and at 1750rpm its doing 80 on the motorway and averges 26mpg over the journey; better than the LS2 and purely down to the gearing I would think.

As the recent picture showed, I have a new petrol/volts gauge. The petrol side is a pain in the arse, if I'm honest. Flicks about constantly, and there's no way to damp it. Under about 25% (you can have it in litres, gallons, or percentage, which is nice) it flicks to empty constantly around corners and such and I've ended up disabling all the alarms (either a flashing light, or the entire gauge can flash; doubly annoying!) and simply ignoring it most of the time. Craig programmed it but after a battery change I had to do it again, which was annoying. I googled 'RX-7 FD3S petrol tank capacity' and found lots of things saying 76 litres. So off down the petrol station I go, after first running it so low I was scared I'd run out; after it said zero per cent I did another 15 miles or so. So.....there are 6 calibration settings; 0 (empty) and 5 (full) then 1, 2, 3 and 4 inbetween (20, 40, 60 and 80 per cent). Set 0, then put in 15 litres (1), then 30 (2), then 45 (3), then 60 (4) then.....CLICK at 62. bks. The japs get a smaller petrol tank, and my googling showed the US version. Sod it. So I set 62.5 litres as FULL and start to understand why, when I got the car back from Craig, it started at 100% when full up then, after about 15 minutes driving, dropped to 80 without anything inbetween, then started counting down in a linear fashion. Maybe they got caught out the same way? I must ask. Anyway, it seems its a 65 litre tank, and I still had 2.5 left when I went to the petrol station! There's a drain plug underneath, but I just get the feeling its one of those things that if you ever touch it, it weeps for ever. Or you strip the thread. Its under a ton of underseal and just seems like one of those things you shouldn't screw with.....

Anyway; start of August was the Goodwood sprint run by the Brighton & Hove Motor Club. I generally do alright here but god I'm rusty, and the wet practice didn't help. I haven't driven this car in anger since the previous august and it shows; my slowest ever time! I warm up slightly for the 1st timed run, and win the class by about half a second on the 2nd timed run, but I'm still 2 seconds off last year's (LS2) time and 3 seconds from my best ever (as a rotary, but I'd done every sprint there that year and was totally 'on it'. Its the last sprint of the year at Goodwood, so.....next year I'll do them all and see if I can get in the 80s.

I bought a new set of 888s especially for the sprint, and didn't want to waste them on a trackday. At a thousand sodding quid for the set, I may even take them to bed with me! They are being saved for sprints and Nurburgring trips, so are tucked up nicely in the house (less heat cycles than in the garage!).

With that in mind I got the 3rd set of wheels I own (nasty cheap 'Work' ones I got off the forum for £200 years ago and have only ever used once) out of the shed, strangely finding a pair of only half worn rear 888s as well in there (bonus!) and bought some slicks off eBay. When they arrived they looked alright, but when I took them to get them fitted the tyre guy pointed out that the DOT numbers on the side told me that two were from 1993, one was 1994, and the 4th one was 2004. Oh. Well what the hell, they had no cracks on them (I've seen one-year-old ones in worse nick) so we fitted them anyway, and was told that they'd most likely be awful for a few laps (they are Dunlops, 235s all round, from a touring car, so should last whole sessions) but may be usable after that, but be careful and don't expect much. Oh, and you might die, said the tyre guy. Pffft. Wuss.

So.....1st trackday. Rockingham, mid August. I fitted the 'death slicks' before I even went and stuck the car on the trailer, taking the 888s as backup. Guess what? The slicks were great, and worked within one lap. I guess they'd been used very little, and dry-stored out of the sun all this time. Having 235 all round (normally 235 up front, and 255 at rear) was entertaining; the hairpin was a giggle; OK, I could destroy ANY tyres round there in 2nd, but these in 3rd gear were brilliant. Turn in late, plant foot on floor, and the back comes out just a little, but I barely have to counter-steer - it doesn't come right round on you. It comes out of the corner four-wheel drifting, the rears spinning and pushing the front slightly, and leaving two dirty great black lines all the way up the track, which drew admiration from the drivers behind. Top fun. The Pif-Paf chicane could be done flat in third, drifting through the whole thing, smearing the tyres front and back. Brilliant. This is the car at its best. Very little got past me. Max was there in his Manthey-tweaked GT3 and we had a great few sessions swapping the lead, until I cleared off a little. Should have kept the Rex and gone V8, Max..... wink

I just remembered, for those building one of these; we could not stop the radiator fan being on all the time. The ECU was switching it on and we don't know why. But my fancy gauges also have outputs.....so now at 90C water temps, the fan comes on, and I can change this any time from the gauge. Nice smile It was at 97, but I want less temps in the car (a recurring theme.....) so I set it lower.

Temperatures though. Still an issue for me, but there are two 'usages' here that are different. One is Track, the other is Road.

Track first; even with the new, larger oil cooler, I was hitting 120C oil temps almost immediately during sessions. Not so the first session, but subsequent ones (where the car hadn't really cooled down after the previous one; 20-30 minutes is not enough when a car has no way of losing oil temperature apart from airflow while moving, and the moving is done while flat out on the next session). It would then creep up by a few C per lap, and I was doing slowdown laps when it hit 130C. Then someone overtook me and I just had to go after them....the most I saw was 134C. I consider this too hot, though several people have told me that with modern motors and oils, it isn't really (Aston Martin run their race cars at 140+ for eight-hour endurance races). Either way, it would continue to climb if I let it. Its worth mentioning here that Taz, a mate with another Craig-built V8 Rex, has no oil gauge whatsoever, and merrily does sessions all day (and did, at Bedford on the same hot day), completly ignorant of what I imagine is his engine screaming for mercy beneath him. Maybe I think too much. Water temps seemed fine, under 110 most of the time, and only climbing to 115 when the oil was around 130 for any length of time. At the end of a session I had to come in and leave the car running until the water gradually came down to under 100; the one time I just came in and turned it off at 115 it spat some water back out of the reservoir in the inner wing (the standard Mazda one which is still there). Started car again and it stopped as the temps came down. All good. Worth mentioning that it did want some water after that trackday; in the bottle by the engine as well as the inner-wing reservoir. Not much, but hot running will boil some away, it seems. Something to check with the oil, before and after track days (and during!).

I'd like to see lower oil temps, or at least it staying static, rather than climbing. Looking at the front of the car its plain that air going into the side pod is hitting the power-steering cooler first and thats covering half the oil cooler really, and that half the air may well be missing everything anyway, and whistling off past the front wheel (the arch-liners are knackered; something else on the list....). Two things to do here; one is to duct the air from that side pod purely into the oil cooler and move the power-steering cooler from in front of it, and the other is giving the car some way to lose oil temps after it stops or is moving slowly. So, off to Birmingham for the day and the power-steering cooler is moved to the other side, next to the air filter. The side pod is ducted on both side and the underneath (we left the top). Then the radiator fan from an Aprilia Tuono (V-Twin 1000cc motorbike; the V-Twins always get hot....£25 from eBay) is attached to the back of the oil cooler. I was going to attach this to the Oil Temp gauge and control it from that (as I did with the rad fan and the water temp gauge) but that would mean the dash coming out AGAIN and its already getting bloody awful with its rattling, so I just said 'balls to it' and ran it off the radiator fan wiring. So at 90C water temps the radiator fan comes on, and the oil cooler fan as well. Just static testing this (leave car ticking over for half an hour....) showed the water and oil stopping at around 95-100 with the bonnet down and around 95 with it up. Putting your hand behind the oil cooler with the fan on....well, you can't leave your hand there. That fan fitted exactly over half of the cooler......so I ordered another and will run them both. We'll see what this has done next time on track.

Now for Road; and this is a very different set of needs. Having driven the car a fair bit now (back and forth to Birmingham, around Peak District, motorways, town stuff (whether stuck in traffic or not)......I now know that if the water or oil temps go much over 90 then the car is a much less comfortable place to be in. I also know the cut-off point for climbing temperatures; its about 40mph. Above that oil and water temps will start to fall, below that (just driving in town, moving around normally) they will start to rise above that. Bear in mind the fans come in at 90C and its plain they are fighting a losing battle. OK, I have no air-con as yet, but I think more can be done. Oil cooler gets two fans, above. But the water temps are the issue; they just keep climbing. So I've ordered some ridiculous rad fan from the states. Next time I'm in Birmngham that and the other oil cooler fan go on and we'll see where we are. Bear in mind the car will not overheat; the most I've seen after getting utterly stationary for half an hour, was 109. But its horrible in the car, so I am trying to get it lower from a comfort point of view, not a 'health of the car' reason. If i can maintain 90 oil and water at a standstill, I'll consider that a personal victory. It may never happen.

The Zircotec coating.......was it worth it? I think if it was cheaper, yes, but I don't know if I'd do it again. £1000 for.......temperatures in the car simply climbing more slowly. It hasn't fixed anything, its a sticking plaster. Spend longer than 20 minutes in traffic and its simply not nice in there. Without the coating it would probably be 10 minutes?

While I'm at it, I'll put my hands up and admit I may well have been wrong about the gearbox. All day on track and the car like a sodding bonfire inside and......shifts the same as when its at normal temperature.

The big thing here is; once it gets hot it takes HOURS of driving on the motorway to get the chassis cool again. Yes, the actual body of the car, the tunnel, the floor, the roll cage, get warm. Not sure I'll ever beat this to be honest, but the aircon will fix it I guess.

The battery? My £180 dry cell Optima thing had been screwing me around for a while (going flat every few weeks last year, though strangely behaving itself perfectly for Craig throughout the 4 months it was in Birmingham this year, the bd) and the afternoon before the track day I find the car absolutely dead. Great. Stick a charger on it and the alarm immediately goes off, and there isn't enough power in the car to tell it to stop. Even better. Yank the battery terminals off and the alarm keeps going off. Charge battery for 10 minutes with alarm going off, while still unplugged. Plug it back in and manage to tell alarm to shut up. Zoom down to local motor factors and try to find something vaguely comparable to the 750 cold cranking amps that it claims to have. Oh, and will also fit in the same hole (the passenger-side rear seat) and still allow my rear-seat unit thingy to fit. End up with the battery from a 2.5 diesel transit. 650 CCA. Also test the dry cell and find it outputting 5 amps, they guy says its knackered and offers to throw it away, but I decide to take it home and stick it on the Optimate and leave it.

Transit battery is perfect, and its nice to have something trustworthy. Also, it seems that I left the lights on. Doh. Now the dry cell (and the car) acting so strangely when I hooked the charger up makes more sense. Oh well. On the plus side, the Optimate has apparently brought the dry cell back to life completely, green lights abound. Which is good, as I must have a dry cell for Sprinting (wet cell must be in a box, and I haven't the room for one). So i guess thats going back in soon.

Wow, I've been typing for about two hours. That'll do for the moment....

Edited by papercup on Tuesday 28th August 12:36

papercup

Original Poster:

2,231 posts

102 months

[news] 
Tuesday 28th August 2012 quote quote all
4packet said:
Shame you're still suffering with the AC. Hope it gets resolved properly this time.

How was Rockingham? Think I saw some pics on FDUK.
Where were the pics? I'm looking now and they aren't on the specific trackday thread....must be on another thread somewhere?


redgriff500

9,253 posts

146 months

[news] 
Tuesday 28th August 2012 quote quote all
Hi,

Re heat issue, what was it like when it was a Rotary ?

Am I right in thinking that heat is directly related to bhp output or is it due to the location / surface area of 8 exhaust manifolds ?

(Probably both)

Have you considered wrapping the manifolds ?

I use a heat blanket (rather than a bandage) on my manifold as I have a supercharger mounted above it and it works very well.

I know it won't solve the heat soak on track but it should help around town.


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