Previous info on the build:
We've finally started doing more work on my friends SR20DET MX-5 build! Very excited about the progress today, next week we'll be replacing the NA dash with a NB one. Everything bolts straight in but wiring has to be modified.
Interior stripped out, NB carpet cleaned up and going into the NA shell.
Next up was the main body wiring harness, this was previously stripped back and modified. This includes a proper relocation of the engine bay fuse box, cleaned up engine bay wiring, and separating the factory combined engine and body wiring.
Last weekend was pretty productive, we started stripping the NA8C half cut. First order of business was to clean up the shed, so while I was sleeping in Duy got to work on that part =)
Our goal was the entire wiring harness from the chassis/body. Unfortunately, this involved removing the entire dash because Mazda in their almighty wisdom decided it was a clever idea to make it all ONE PIECE!
Just some better photos of the NA8 halfcut, whole thing is pretty damn clean and only has 70,000KMs on it.
It's been nearly four months since any progress has been made on the MX-5 builds. Has been way too long... luckily Duy has picked up the NA8 half cut from MX-5 Plus.
The silver MX-5 will be converted back to a standard NA8 using this half cut. The black shell will be receiving the SR20DET and all the other JDM goodies =)
So last couple of days I started to re-assemble my engine with some help from friends. Not bad timing since I was due for my 5000km service anyway =)
Since I had to replace my gasket, I decided to spend a little extra and went with a Tomei 1.2mm head gasket and ARP head studs. A good upgrade because the factory gasket and head bolts don't like running high boost. So now I can run higher boost! Exciting for me.
As mentioned in the previous post, my S15 was performing like a champion at the track. Water temps stayed between 80-85°C the whole time and oil temps staying below 90°C. Couldn't have asked for a better result.
But tragedy struck after entering the pits and we lifted the bonnet... Roughly 750mL of coolant was pushed into the overflow bottle, which is very strange because the car never overheated. Even stranger was that the coolant in the overflow never sucked back into the radiator, we even left it to cool for about 60-90mins.
After some reading, testing and talking to a few workshops. We concluded that combustion gases were leaking into the cooling system when the car was on boost. This pressurised the cooling system and forced coolant passed the radiator cap and into the overflow bottle.
Initially I decided I would send it to a workshop to get my S15 repaired, but my mates Duy and Jess convinced me that I should do it myself at home (with help of course!). So below is the progress from today...
Over the last couple of weeks I've had the chance to test out three different thermostats in my S15, genuine and after-market. They all have pros and cons, all of it really depending on the cooling system as well as main use of the car.
The three thermostats I have tested are:
- Nissan 76.5°C
- Nismo 62.5°C
- Tridon High Flow 76.5°C
Updates 13/07/2011 - further testing/observations
Updates 14/07/2011 - bad news
You will have probably seen the under-bodies of many supercars, and noticed that some of them are very flat. Wind tunnel data has shown that the under-body makes up to 30% of the vehicle's total drag, which is why engineers try to reduce the drag as much as possible so that air flow is fast moving and therefore low pressure. This low pressure acts a sucking force and increases overall downforce, even more so when a rear diffuser and front splitters are used. In fact, many race series ban the use of flat under-bodies because it is so effective at increasing downforce and not introducing much drag.
After installing dual thermo fans into my S15, I've been addicted to the topic of engine cooling. Although it seems like simple system, consisting of a radiator - water pump - thermostat - cooling fan, it can get quite complicated once your car starts producing a lot more power than the cooling system was designed for. This is especially true when it comes to SR20DETs, the factory cooling system doesn't allow for much headroom and temps will quickly rise once you constantly stay on boost. Not only will the cooling system be insufficient, it'll also be inefficient with a stock clutch fan.
I love having so much space in the engine bay now! It makes many jobs just so much easier and also helps to spot any oil/coolant leaks. I noticed that my water pump started leaking from the weep hole, this is an indicator to show that the internal seal is on it's way out. Thought it was a perfect time to replace my thermostat too.
I normally prefer to go genuine parts whenever I can. So when it came to replacing my water pump and thermostat, I got in contact with TAARK for cheap genuine parts.
Wasn't much of a car day today, didn't get much done at all because I had some uni and COEM Audio stuff to attend to.
I went by Extreme Motorsports and Enzed to pick up some parts, and then dropped off my intake manifold at Clifton Engineering to get a hole tapped for the VDO temp sender. Most of my other parts were already ordered from Summit Racing in the US.
My efforts from today -