Subaru Impreza build thread...
Subaru Impreza build thread...
great job mate you really know your stuff ! not been on here for a while but i'm glad i spotted this thread great read love imprezas i'm on my 5th lol hope to see you at some shows / meets this year been the only impreza at the last 2 i went too
Great thread mate, sadly im extremely jealous of people like you. You have the time and facilities to do all this work. I would love to be able to strip my motor right down and give it a full rebuild. Anyway keep it coming buddy, enjoyed the read so far
So, after many months of buggering around, I've finally managed to get the custom drive shafts made!
No matter what combination of inner and outer CV's I tried, I simply couldn't make the old 5 speed shafts work with the new 6 speed ones.
This led to the conclusion that 2 drive shafts need to be mated together to create one through the process of friction welding.
They should be stronger, if not the same as they were before.
They're now in the car and the transmission is completely installed. I even took it home last weekend to put some 'shakedown' mileage on it.
It started out a little notchy and I was unable to rush the gear changes but the more miles i covered, the better it felt and by the time i'd covered 50 or so miles, it was as good as new!
Needless to say, when looking out of the office window now, I'm greeted with a happy view!
The diff balance has totally changed. The car is now a lot more power biased towards the rear and the diffs are more aggressive.
The rear diff is a plate type diff but isn't snatchy like most I've driven in the past. The front diff is quite passive until you get on the power then you can really feel it starting to pull the front end around the corners.
I still haven't really driven it in anger yet but I'm hoping to get a track day booked in March to see what it'll really do.
The gear ratios are nothing like they were before.
1st is pretty much the same.
2nd has lost 10mph.
3rd gear is short by almost 20mph.
4th is shorter by almost 34mph
5th has lost the same again.
6th gear is very long, taking me up to over 190mph
Here's a comparison of the RPM / gear / speed:
OK. So the last few months has seen the car laid up and in pieces again.
This time around I've removed the HKS intercooler and all of it's pipe work for a bit of a freshen up. The core itself was getting a bit old and knackered after spending 4 years being pelted with stones, rocks, road kill etc and the cooling fins weren't in the best of health. To give you an idea of how bad it was, you couldn't actually see through it. If light cant get through then how the hell is air supposed to? lol
With this in mind I sent it off to the guys at ProAlloy to have a new race core grafted in between the HKS end tanks. A week later...
In the mean time, I'd shot blasted all of the pipework and added new braces and brackets to make the whole thing more secure.
Then, with the aid of a friends garage and his painting equipment, everything got a good coat of zinc cromate primer and finished in 2-pack gloss black to suit the intercooler core.
Several thin coats later and it was all looking very nice indeed. As well as the pipework, I also painted the auxiliary belt guard and the tops of the coolant tank and power steering tank.These were painted back when I built the engine but they didn't weather too well.
The next phase was to help keep the oil temperatures under control.
Despite having abused the car for several years now, it's never had any additional oil cooling. It's only once I started to data log the oil temperatures that I noticed they were occasionally getting to 120+ degrees.
With this in mind, it was time to get drastic. Firstly the air-con system had to go. Not only were the air-con radiator fins full of rubbish (which was easily cleaned out) but also I had the extra weight to consider. In grand total, the air-con system weighed approximately 29 kilos. It also removed an air flow restriction to the engine coolant radiator to aid in cooler running temperatures. This in itself will help the engine oil temperatures but not by a lot.
After a bit of shopping around, I purchased this:
Some might say it's a bit overkill but since it'll be thermostatically controlled, there's no real downside to having it larger than required. The hardest part was custom designing and fabricating the brackets in order to have it sitting in just the right place.
With the pipework painted and the new intercooler, it's time to start putting it back together.
Starting with the intercooler pipes on the hot side and the intake pipe work.
For now, I'm reusing the original HKS silicon joiners. The plan is to replace these with some custom TDI joiners in black with new stainless steel mikalor clamps.
Installing the cold side of the pipework and my sexy new HKS SSQV Black Edition. Om Nom Nom...
You can see that because of the oil cooler mounted so close to the coolant radiator, the power steering cooler bar has to be relocated. Whether this solution will work or not remains to be seen. I may have to put a proper cooler in...
The intercooler core being trial fitted before I remade the custom brackets...
To avoid the core degradation that the last intercooler suffered from, this time I've fitted some good quality mesh.
Bumper back on and the lights refitted...
The weekend saw some interesting developments on the project. Some good & some bad.
First job on the list was to change my actuator. Whilst there was nothing wrong with the old unit, it was set at 0.8bar and was being over powered at high RPM's on higher boost settings. Turbo Dynamics supplied me with a new actuator set to 1.0bar to hopefully solve the problem.
Here's the old actuator and the new one with it.
With the preload measured, the actuator arm is transferred over to ensure an identical fit.
It was then time to get it to TDI and start developing the mapping again. This should have been relatively straight forward but these things never are. With Wednesday's track day looming, I had to get things finished and leave enough time for a shake down.
At actuator pressure, it was doing exactly as we'd predicted. At only 1.0bar of boost pressure, she's currently making 294bhp at the hubs.
As soon as we tried turning up the boost, the fuel pressure was dropping off like a stone. The voltage at the pump was measured and the fuel filter was checked also - neither of these were at fault.
I removed the fuel pump only to discover that the Walbro 255 pump the car should have had (and is in the receipts too) actually turns out to be an OEM pump and it's on its last legs! Needless to say, I was properly disappointed.
To cheer myself up, I wrapped my front splitter and lower bumper segment in carbon fibre... It's the little things.