Snowed in as Cambridgeshire ground to a halt with a couple of inches of snow. Took the opportunity to fit the scuttle, for some reason this required a lot more trimming on one of the locating blocks than the others. I'm dont think that it's a problem with the body but I suspect I would have been better off leaving the last few locating rivets on the main tub till after the scuttle was fixed, that would have allowed a little flex to help everything line up.
Connected up and routed some of the wiring and pipework, routing the brake level line through the old hole in the scuttle and using plenty of hose clips to hold it down. The expansion tank top connection is now routed through ali tubing and silicone hoses and clipped securely in place.
Sorted out a lot more cabling, preparing the runs for the intercooler fan switch. I've decided not to use the thermostatic control that I have since I'm pretty syre that it won't react quickly enough to make a lot of difference and I'm rather cautious of having a sensor dangling in the airflow. If it were to break off it would end up heading at speed towards the engine and probably result in an engine rebuild.
As part of the wiring tidy up I sent some tim wrapping all the new loom sections with proper loom tape, as a result it's a lot neater and I'm now tempted to unwind part of the engine loom and tidy that up.
I've also ordered a Toad immiboliser, it really can't hurt to keep the car as secure as possible. It's not a complete security solution but hopefully it's a deterent of some sort.
Decided to bite the bullet and re-wrap a chunk of the engine loom that lived under the dash. In doing so found a completely redundant section and neatened the whole thing up no end. I'm still not 100% happy with it but there's definately sufficient space to put the immobiliser now. I think I'm going to do another itteration of the re-wrap as some of it is still in convoluted tubing which makes it difficult to bend into a convenient route. Whipping that off and wrapping it as a bundle would help significantly. I also wrapped up the bundle of cables that comes under the dash and over to the fuses, in this case though I used some spirwrap, largely because the fitment isn't 100% finalised and I may need access to that section later. It still looks the part though. Routing the lambda sensor wiring through this has helped keep things neat and tidy.
I still have a lot of work to do in the engine bay, including shortening up a lot of the new wiring to the correct lengths, wrapping and routing all of that and then fixing it all down.
The immobiliser I ordered arrived so had a peer at how to wire that in, nothing looks too difficult really. Need to sleep on it though so it's a job for another day
At long last the second revision of the intercooler design, this will fit vertically in front of the engine, between the rails and with a fan to help the airflow over it. I still need to make up a prototype to check fitment but this is getting nearer the final design. This design gives 9.6 litres of core volume, close to that of the R500 design, which I know will give a 65°C temperature drop from 105-40°C. The current cooler isn't doing half that well so I'm not only loosing power but also risking detonation. Thankfully the pectel setup has good knock detection.
I spent the evening with a big box of aeroquip fittings attempting to plumb in the breather and oil cooler. In reality all I did was discover that the "push on" fittings that I was sold aren't actually suitable for the braided hose that I have. The cost of changing the hose is comparable to that of changing the fittings, looking at it practically though it will be easier to change the hose since the access is so poor. On monday I guess there's going to be a big order to Rally Design or Think.
A rather more productive day today. The engine wiring is nearly all done now, once again I spent a fair amount of time re-wrapping sections of the loom, pulling together portions that followed the same route. The result is the under dash area is now pretty neat and tidy, as is the engine bay.
Tweaked the orientation of the turbo compressor housing now that everything is in position, this should give a little more clearance under the bonnet and will make routing the intercooler hoses a bit easier. I also made up a new intercooler prototype to my latest plans but hit a big problem in that it won't fit in with the engine in place. I was pretty sure my calculations indicated that it would fit so it may well just been that my slightly simplified prototype wasn't accurate enough. In any case it's back to the drawing board.
I've just spent a fruitless couple of hours trying to figure out another version of my intercooler design that can be fitted and removed with the engine in place. I started off by trying to load the mock-up from the front and removed the ARB to make things easier. In reality it didn't help a great deal. Next idea was to cut down the height to make it easier to get into the vertical position after front loading. Still no joy. After that I went back to a top loading design, tweaking the sizes and tapers of the end tanks to make them easier to get in. More by luck than anything I found a compromise that would just fit in. Unfortunately once it was in I couldn't get it out without whipping off the tanks.
It seems that I can get a 10 litre core into the space pretty easily, I just need the engine out of the way. With the engine in place I can't get bigger than a 6ltr core which is only 30% up from the standard Westfield item. I've toyed with the idea of top and bottom mounted tanks using a two pass IC design but doesn't help enough to justify the extra complexity and cost. The thing that really would help is making the bottom lateral rail in front of the engine removable but there's a lot of forces being transfered from the suspension around there so again not a great idea.
I've also considered a design with detachable end tanks but I thing that's too complex really, the only other hope would be a twin IC setup but that has other issues due to the pressure drop etc. I'm wondering if perhaps an AWIC is the only way after all.
A pile of electrical bits arrived from VWP today, the main purpose of the order was to find a suitable switch for the intercooler fan. Despite ordering one of each that they had I still didn't find one that was really appropriate. It looks like a toggle switch will look a lot better.
Thinking about intercoolers more I suspect a twin intercooler setup is going to be the only approach. Forge look like they have some hopefull looking ones for me to get the measurements of.
Thought briefly again about intercoolers and have rekindled the idea of a double pass solution since forge seem able to make these fairly easily. The problem tends to be that the split end tanks aren't perfectly sealed and thus air can bypass the cooling core. Forge seem to have cracked this nut though by making the sections seperately then welding them together.
To get within my preferred design constraints I can't really get any bigger than 5 litres, not a great improvement but I would get fan assistance. To go taller I'd have to do some substantial rerouting of pipework which I'm not entirely sure is going to be feasible. If it were then I could conceivably be looking at a 7.5 ltr core which would be more like it. The alternative is to narrow the core and to make it thicker. Again it is possible I could get over 7 ltr.
All these intercooler options are making my brain hurt and getting me nowhere so I decided to work on something different, ie the boot box. This is something I've been dreading and looking forward to at the same time. The challenge to make it fit which makes it interesting and most of all it's something that isn't bloomin intercoolers.
Taking the bootbox down from it's storage location and cleaning it up it becomes apparent that at some point someone cut an access panel in it then glassed it back up fairly roughly and covered the join with gaffer tape. I can only presume the panel was to help get at the CV joints since that's the only thing in that location. It's all easy to put right since I'll be chopping the box into many small parts anyway.
Suprisingly it looks like only a small portion needs to be removed to clear the larger fuel tank and I think I've worked out how to chop the box up. I obviously have to take out the chunk to clear the tank but it looks like one cut, down the middle of the box between the rear braces should be enough to get the box in, the only other cut will be along the length of the front lip so that the trip can slip round the front of the main uprights. This latter part may not even need refitting since there is a trim piece to cover this that will be fitted on later.
Obviously a lot of measuring and trimming is required but I'm reaonably upbeat about it. I'm even beginning to think that the top box may be doable too.
The chargecooler idea is becomming more appealing to me, I have the space for an oil cooler (19 or maybe 25 row) in front of the rad for the water from the chargecooler. Not running a second fan would mean that the circuitry that I've installed for it would nicely run a water pump. A small 13ltr/min pump from think is £80, the oil cooler £90, a 4"x8" header tank is £76 from forge. The big unkown will be the chargecooler, which by the looks of it would be around £600 plus plumbing. I've asked Pace a few questions so we'll find out what their advice is soon enough
My rough calculations are that a 19 row oil cooler could disappate about 5KW of heat based on a flow rate of 13ltr/min and limited airspeed, at higher speeds the dissapation could be doubled. Working back that dissapation that would amount to cooling those 13 litres of water by about 5°C, adjusting for a likely coolant volume of about 6 ltr that's a 10C drop.
Air has a much lower SHC than water so it's equivalent to a 40C drop in air temperature of the same flow. My rough calculations show that a 60°C drop with the engine at 6000rpm would need 10000KW of heat disappating. That's clearly wrong so I'm obviously missing something.
Attacked the boot box with a jigsaw after measuring everything at least 3 times. Definately not something for the faint hearted, in the space of about 3 minutes I'd ruined a couple of hundred pounds worth of GRP. Fortunately the 3 sections drop into the boot perfectly. There is quite a lot of work to make up a new section to cover the long range fuel tank and to add lips and clips to join the sections together. I'll also need to research some appropriate trim.
Broadly speaking what I've done it split the font and rear portions of the box along the line that the rear roll bar supports pass through it. The front section has been chopped in two where the vertical brace goes, behind the drivers head. I've then chopped the front corners of the box off to go round the main roll bar verticals.
Looking at the top-box I think I've also figured out how to fit that on as well with only relatively minor modifications. That being to cut out the 2" wide strip ahead of the braces, thereby allowing the lid to hinge up. These panels can be fixed permanantly in place. The other modification is to cut out the front portion of the top box surround. With that as a seperate item it should be easy to slip into place and fasten down. If it all works out it should be possible to hide most of the joins so that it looks a reasonably professional job.
The last thing I did was work out a cunning way to enable me to test the engine without to worry abou the immobiliser. I'm obviously not going to tell you how I'm doing it but suffice to say it's easy for me but hard for anyone else! The next job is obviously to fit the immobiliser itself, which means ripping and redoing a lot of the wiring that I'd lovingly installed.
I haven't completely forgotten about the intercooler but I am trying! I did measure up the space for an oil cooler and I definately have space for a 25 row one, the space being about 300x220x50mm. The best matches for that space for a water rad would be a 1x28 or a 1x40 core, which work out as a total depth of 40mm and 52mm respectively. Max core size, allowing for end tanks would be 240x220, which is about the minimum size that pace sell but would still be a tight fit. To me it looks like the oil cooler may be the better bet.
I also thought a bit about the relative volumes of the cores of an intercooler vs a chargecooler heat exchanger. A 10l AAIC compares to a 2.5ltr AWIC but we do need to factor in the extra level of heat exchange. The 2 core pace exchanger comes in at about 3.6ltr so that should be adequate for my purposes, the bit I do worry about is the water to air stage if I'm using an oil cooler. The 25 row cooler only gives me 2.5ltr of volume which isn't as much as I would like. In theory though since you're not on boost all the time the volume of water will smooth the temperature spikes.
Finally got to speak to Forge and Pace about intercoolers. The conclusion is that Forge regard ICs as the way to go but will do chargecooler if I really want. They were extremely helpful and are able to make the pretty complex design that I'm after. The one suprising thing was that they didn't seem to think the size and shape of the end tanks was too important, far better to have a big core and the air, being pressureized will find it's way around easily enough.
It's taken me a while to get hold of the relevant person at Pace because they've been so busy but they were very helpfull. I spoke to wayne in some depth about chargecoolers, they've now done a couple of cossie westfield installations. One I already knew about the other is a new one, a sprinter with a 400BHP setup used one of their 4 core heat exchangers, in conjunction with a skinny pre-rad that covered the water rad. Even this couldn't cope with full-boost so to smooth out the spikes they installed a large water tank in the boot area.
The big things that they pointed out was that the IC needs the coldest possible air to be effective (pretty obvious really) and that it's far more sensitive to such things than the rad or an oil cooler. Therefore it's vital to have the IC in unobstructed fresh airflow and you mustn't subject it to anything that could cause heat soak. They also pointed out that an oil cooler puts out an awful lot of heat and isn't terribly sensitive so ideally wants to go at the very back of the pile of cooling devices.
Their recommendation was that a 4 core heat exchanger, in combination with a skinny 18mm pre-rad covering the whole of the radiator is the way to go. A 25 row oil cooler would be just about equivalent but being 50mm thick the airflow to the rad would be slightly obstructed and there would be some heat soak. Not ideal but it might be a starting point.
I haven't drawn any firm conclusions yet but I think the route forward is to make a final mock up IC for forge to quote against. If that doesn't look viable to take a pace chargecooler, initially with an oil cooler as the rad and to consider re-doing the radiators if they aren't up to the job.
Spoke to Questmead and as per their promise they've caught up with the back orders and my new brake pads are being shipped out. In future they'll have everything in stock so I shouldn't have to wait again.
Started connecting up the breather system and was shocked by the amount of force required to fit a -12 double-cutter fitting. I guess it shouldn't be that much of a suprise since you're forcing a bluntish piece of metal to cut into a piece of heavy duty rubber at the same time as compressing it.
Mocked up a further revised intercooler design and managed to get a 280x280x100mm core into the space! The end tanks are smaller than I'd like but I can tweak that further.
Having read the turbocharging and intercooling section of Graham Bell's books and cogitated over the conversations with Pace and Forge yesterday I think I have a plan of action. Initially I'll fit a decent sized IC as planned which means I can keep nice short pipework and have a simpleish installation. If that proves to be insufficient then I'm going to look at using the nosecone for a large intercooler with oil cooler mounted behind it. The radiator would be relocated either in front of the engine, under the rear of the car, or into ducts on the side of the body. Lots of options if I need to go down that route.
Made up and connected another of the breather pipes up, while I was at it I adjusted some of the routing to make space for the oil cooler pipework.
After someone (I won't say who) got very excited about the prospect of fitting ali pipework to their car I swapped out one of the long legths of flexi hose in favour of a couple of feet of ali. The ali pipework is not only tougher than silicone but is slightly lighter as well. The only proviso with it is that you have to make sure that there is some flexi hose in the system to allow the engine to move around a little.
I think I've figured out a working intercooler design at last, capturing the design fully enough for someone to manufacture is going to be interesting.
The brake pads have turned up so I fitted one set but realied I'd run out of bolts of the right length for mounting the calipers. I'll pop out and get some M10x40 bolts tomorrow.
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