Archive March 2010
Crankcase Vent Tank
In 2009 the One Lap VR-4 struggled with crank case pressure and oil control. We were using the stock 3/8″ fitting off the valve cover feeding to a .75 quart catch can. The stock PCV system was retained with a new PCV valve. We found that after a 4 minute hot lapping session the catch can would fill and blow oil out of the filter all over the engine bay. That meant that we not only risked getting DQ’d for leaking oil but we were at serious risk of a fire. Hot oil has this uncanny way of bursting into flames when you least expect it.
At the top of our to do list for 2010 was to design and build a better system. We took a lot of advice from the NABR and Galant VR-4 guys and this is what we came up with. Its basically a welded aluminum tank with two 8 AN feed lines from the valve cover. It has a 12 AN port which will connect to the pre-turbo intake pipe to provide a source of vacuum to the tank. The really cool feature is a 6 AN drain port on the bottom which will allow the oil to flow back out of the tank and back into the block via the rear balance shaft inspection hole. We can do this because we have removed the balance shafts from the motor. Finally, the tank measures 3.75 quarts in volume so we should have lots of capacity and no hot oil flying around under the hood.
I started with section of 4″ extruded aluminum tube that I had left over from building intake manifolds. The plan is to mount the tank along side the fuse box that sits in front of the passenger side wheel well along the fender. That will give a strait shot from the valve cover and should be close enough to the intake to make connecting it a snap. To cut the stock I am using a table saw with carbide blade. Sounds dangerous but the blade is designed to cut metal and except for the flying bits of aluminum its no worse then cutting wood.
Instead of weld AN fittings I am using the cheapest hose ends I can find and then modifying them to fit. The real head scratcher for me was how to design the inside of the tank. What I did was to kind of box off the two 8 AN inlets so they would blow against a wall. That way the oil could just run off the wall into the sump. I also boxed off the 12 AN vacuum port so even if oil was flying around inside the tank there would be no way for it to get to it. Finally I decided to wedge some scotch-brite pads between the vacuum box and the tank. I am hoping that the surface area of the pads will allow oil vapor to condense and drain out before it gets to the intake pipe. Honestly, I just don’t know how its going to work until its on the car and we are half-way across the Nation.
On the valve cover I used the existing vent port. I knocked the stock steel tube by clamping it with a vice grip and then whacking the vice grips with a hammer until it came out. I then drilled out the hole to 5/8″ (8 AN) and welded it all up. The second port was mounted right next to it but I was forced to install it at a slight angle to allow it to clear the thermostat housing. To get the stock baffle out I drilled out the little nubs and pulled it out. I made an attempt to reinstall it but my welding skills aren’t that great and I just ended up blowing holes in the thin aluminum baffle. So I made my own out of some 1/8″ sheet. I traced the outline using the old baffle and then welded two tabs to keep oil form getting in from the top. Its not pretty but it covers to ports and thats all I needed it to do.
Its not totally finished yet. I still have to make the lines, install the tank under the hood, and make the connection to the BS inspection port. I will update this when its all in and tested.
…as promised I have some updated photos which show the tank installed. I wanted it to fit tighter to the fuse box but the two wire looms would not move enough to let it fit. So it sits an inch or so closer to the valve cover then I wanted but I still think it fits well. For now, I’ve also decided to cap off the PCV system. I may or may not bring it back depending how the tank works without it.
Tire Selection: Yokohama ADVAN Neova AD08
As the 2010 One Lap of America event approaches, we had to decide on a set of tires to go with on the Evo X. Since the VR4 already had two new Dunlop Starspecs from last year, their decision was to stick with them again this year. Looking at the sizes available for mounting to the 19×9.5″ wheels we found out that the moderately priced Dunlops were not made in the 19″ size we would need, and I didn’t want to compromise by going back down to the stock 18×8.5″ wheels. After comparing all the options it as really down to two choices: Bridgestone RE11 and Yokohama AD08 tires.
As you can see in the video they are pretty much a dead heat between 1st and 2nd place and depending on what attributes you valued most the test results may be swayed one way or the other. I’ve found that the Evo X’s suspension is already very good at realing in highly responsive tires so that negative effect on wet handling stability shouldn’t be an issue assuming we don’t make the car handle twitchy at the limits with the new BC Racing ER series coilovers. The last few times I’ve had the car out on the track during wet conditions, I was one of the few cars able to lay down nearly full power on corner exits and still feel comfortable using moderate braking zones adjusted for a wet line depending on what kind of water was pooling on the track.
I won’t have them mounted until the 2nd or 3rd week in April but I can already tell they are going to handle quite a bit better than the Pirelli P-Zero Nero tires I have mounted now. When I went from the stock Yokohama 245/40-18 tires to the 
Pirelli P-Zero Nero 275/30-19 tire I felt that I made a tradeoff by going with a 15% wider tire that was easily 15% less sticky after several track visits that resulted in a combo that handled about the same but perhaps had a bit better wear rates. I anticipate that these tires will be even stickier than the stock compound and have a wider contact patch which should result in lateral G’s pushing well above the stock .99g mark!
We have 100′ Skidpad testing planned so that we can compare the stock Yokohama tires on stock 18×8.5″ wheels with a stock suspension against the wider Yokohama AD08 tires on 19×9.5″ wheels with Coilover suspension. If there is time we’ll even swap the tires and wheels between the cars to get some more data points to see if the tires or suspension are helping lateral G’s the most. What’s even nicer is that for a limited time there’s a $75 rebate when you buy 4 of these tires from the Tirerack.com before April 30, 2010!
Once we complete the 4500+ miles that we’ll be placing on these tires for the 2010 One Lap of America, Sean and I will give our first hand impressions of daily driving attributes as well how it holds the track at the limits of wet and dry traction so stay tuned!
0EvoX – I’m not fat, I’m big boned
So Saturday came and went and we were able to get the suspension on the EvoX a little more dialed in. A huge thanks goes out the Emery and the guys at Street Tuned Motorsports especially Austin and Ryan as they let us take up their time at the shop on the lift.
After the BC Coilover install and the very basic alignment, we were able to get a very good feel on how the new suspension was going to alter the handling feel over the Eibach spring setup. The car is more compliant, more responsive, and most important, its easier to predict the dynamics of the car under power, braking, bump and recoil. So far, we are pretty darn happy with the initial impressions and setup. Over the next coming weeks, we’ll be mapping out the various shock settings to give us a good suspension tune map before we take off for OneLap.
As far as the corner weighting, let’s start off by saying the car is no lightweight. With Chris as the driver, total weight is in around 3650 give or take a few pounds. Luckily for us there’s plenty of power on tap to account for it. Regardless we may undergo some attempts at dropping some weight before we take off but for now, it’s a back burner “if we have time” kind of thing.
The corner weighting was pretty straight forward. We were able to use Emery’s scales as well as his lift which made things go a lot faster. With that being said, what we did was time constricted so we did a very modified version of what **should** be done to corner weight a car. For those with unlimited access, time and resources, ideally you want to start with a completely flat surface, with the shocks and sway bars disconnected, and the ability to move physical weight around the car as needed. We didn’t really have those options to us so we made to with what we could. We focused mainly on what the cross balance and left/right balances were.
In its starting, post-install form, the car was front right heavy and right rear light. That gave us a left-right balance of 46%/54% which isn’t so good and a crossweight of about 50.8% which is actually pretty damn good. We knew with the EvoX that it would be nose heavy and we were right. The balance was about 58% front/42% rear. As we didn’t have the ability to shift the physical weight around, we’d be focusing on the left-right and crossweight balancing as best we could.
If you want to read a decent primer on suspension geometry/corner weight balancing review the PDF here.
So we started in on the loads/preload/perch heights on the fronts to try to shift the load around a bit. Getting the fronts done didn’t take too long but that threw us off of the ideal of 50/50 left to right and 50 on the cross weight. The rears were a bit more of a pain. As you adjust each corner, forces shift back to the other 3 corners in various amounts depending on what functional items are still attached. Focusing on just getting the front close was easier as we somewhat ignored the rears but as we adjusted each rear corner we have to take into account the other corners. This is the main reason you want to disconnect shocks and swaybars or other weight-shift type applications. You want any transfer be through the body and truly a static corner change. Swaybars and shocks should be used to manage the rate of dynamic transfer. So as we adjusted the rear, it altered the other corners in ways that weren’t as directly linear as we would have liked or expected.
But we persevered as we were on a time crunch and were able to get it damn close considering the situation. Below are the final numbers:
Front Left: 1061 Front Right: 1066
Rear Left: 799 Rear Right: 728
Total Weight: 3654
Left/Right Balance: 50.9%/49.1%
Crossweight: 49%/51%
Note: In the picture the input sides are reversed.
So although not perfectly 50% for left-right as well as cross weight balance, it’s definitely much closer to where we want it. The Front to rear there’s not much we can do at the moment without physically moving/removing weight from the overall car. We also did another camber check although we will be tweaking that as we get the feeling for the car.
2BC Racing Coilovers Installed on the OneLap EvoX
The BC Racing ER Series Coilovers from Darkside Engineering are now installed!
Chris and I spent Saturday working on getting the coilovers installed. The BC Racing coilovers are definitely a quality set of coilovers. They offer both spring preload perches as well as lower mount/body adjustments independent of each other. The ER series we have for the EvoX include remote reservoirs that connect to the main shock body at the bottom end via a small braided stainless-steel high-pressure connector. The adjusters are easy to manipulate for both rebound and bound ( compression ) and the entire unit is well constructed. Definitely looks good at first glance. But how would they perform? And how easy would they be to install?
We’ll post up a full review once we have finalized the install and done our install inspection after the entire system has settled. We still have to finish corner weighting and finalizing the camber/toe settings which will happen this upcoming weekend. Chris is already getting the feel of having a real coilover suspension after riding on Eibach drop springs for a while.
For now, enjoy some teaser pics below!
RochesterDSM One Lap Team featured in Mitsubishi Gearbox Magazine
The RochesterDSM One Lap team is featured this month in Mitsubishi Gearbox Magazine. There is a great story and some cool photos too.
