Wheel alignment!

Now that I've got my RCA fixed, it's time to do my wheel alignment. Honestly its quite hard to drive after the new RCA was swapped in as all the alignment was off.

I'm trying a less aggressive settings this time around:

Camber Front Left: -2.25 degrees
Toe Front Left: 0 degrees

Camber Front Right: -2.13 degrees
Toe Front Right: 0 degrees

Total Front Toe: 0 degrees

----

Camber Rear Left: -2.16 degrees
Toe Front Left: 0 degrees

Camber Front Right: -2.03 degrees
Toe Front Right: 0 degrees

Total Rear Toe: 0 degrees


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The mechanic told me that setting both front and rear camber to be the same, it should help with quicker turn in. Let's see if it's true and he's just lazy to adjust :-)

My car up on the hoist :

Got my RCA fixed and downpipe installed

When I last went for my wheel alignment, the mechanic told me he couldn't do it coz my steering rod and my tie rod was damaged. He demonstrated by shaking my front left wheel to show it was loose.

Ok, so today I finally got it fixed at BMS. It runs out it was not caused by the steering rod but by the tie rod. I replaced it with Whiteline's Roll Center Adjust (RCA) and the joints had worn out. BMS told me to get it swapped by Simon (the guy who it to me). I was surprised that he didn't asked too many questions and offered to swap it with a new one. Apparently the mechanics at BMS told me that this has happened to a few other cars. Simon also admitted this. I noticed the new RCA had a slightly different design (see below).





Another thing I found out also was that my ABS sensor was damaged and the ABS "teeth" on my driveshaft is missing! (Probably damaged when my wheel knuckle was damaged).

Here's how the ABS teeth should look like:



See the missing "teeth" on my drive shaft.


How the ABS works is that an electronic sensor is located on top of the teeth such that as the drive shaft rotates, the teeth will create a pulse onto the ABS sensor - causing ABS to be activated and preventing skidding. Interesting. Ah Boon taught me this today.

At the same, I also took the opportunity to change my illegal 3inch downpipe HeeHee. Whilst changing the RCA, Ah Meng (BMS mechanic) found that one of my front brake pads was worn out. So I changed to Project Mu 777. It feels awesome but they are 300-800 degrees.

My worn out pads:


Project Mu 777 pads (S$450)


New pads!!!


Well, that's it for today - those will be my Xmas presents for myself :-)

Day1 of 300g/s hack

Ok, here's an update. The car feels slightly sluggish before flashing the hacked ROM. One reason I can think of is that e.g. for each g/s, although the values have been reduced, I kept the same timing for each cell. Therefore, I need to modify these cells.

Let me think more about this...

Changes to workaround 300g/s

Ok, I've just made changes to the following tables:

Primary Open Loop Fueling
Primary Open Loop Fueling (Failsafe)
Injector Flow Scaling
A/F Learning #1 Airflow Ranges
Base Timing
Timing Advance (Maximum)
Feedback Correction Minimum Load
Fine Correction Range (Load)
Rough Correction Range (Load)
MAF Sensor Scaling
Fine Correction Columns (Load)
Timing Comp Min Load (Intake Temp)
Timing Comp Minimum Load (Per Cylinder)


All LOAD(g/rev) values & MAF Flow(g/sec) values in the tables listed need to be multiplied by the same value. In my case, I multiplied all of them by 0.7.

I'm going to flash this and see how the car behaves. If all goes well, I post screenshots of the changes :-)

How to lower IDC?

It's important to keep IDC within an acceptable range (about 80%) so that when there is a sudden increase in airflow (e.g. on a cold day), one does not run lean suddenly and blow up the engine.

There's 4 ways to lower IDC:
1) lower your target boost above 5500rpm
2) lean out the afr above 5500rpm
3) mod your stock injectors
4) buy bigger injectors

Here's an interesting discussion on NASIOC.

I quote eggroll's comments which I think summarises it best:
The FPR will adjust fuel pressure to keep it 43 psi above the manifold pressure. The reason it does this is because the injectors are squirting fuel into, that's right, the manifold. If the fuel pressure remained at 43 psig, and the manifold pressure rose from 0 psig to 21.5 psig, even at the same IDC you would only be getting half the fuel, since the effective fuel pressure would only be 21.5 psig (43-21.5). This means that if there's a boost spike, it will only increase fuel pressure to keep a constant 43 psi differential between the fuel pressure and the manifold pressure, to allow your injectors to work as effectively at this higher pressure as they did at the lower pressure. This is completely separate from your injector potential, IDC, target AFR, everything (as long as it's working properly).

If you get a boost spike, your air flow will increase, which will cause your MAF voltage to increase. In turn the ECU will register that you have more airflow, and it will increase the IDC to add enough fuel to compensate. If your IDC cannot go any higher, you will get no extra fuel, and that extra air will cause a lean condition. Say you got a spike that increased airflow by 15% (not uncommon). If you are already at the injector limit, that 15% increase in airflow will cause your AFR to swing 15% more lean. If you were running at 11:1, you will swing to 12.65:1, add that to the fact that you're already running more boost than the car was tuned for, and you can see where the engine is headed...

300g/s limit on 16bit ECU

Ok, the reason why I need to re-scale my MAF is because for 16-bit ecu, there is a 300g/s limit. For cars like mine which has a bigger MAF housing, it's easy to hit this limit.

I mentioned a post on Romraider in my yesterday's post but the guys are not really working on it right now. It points to a link on NASIOC here which has a better workaround. I'll be working on this for now.

Rescale my MAFv table

Base on my last log, I think my next step is to re-scale my MAFv table which has reached its limit. This is due to the 16bit ecu. It'll be interesting how to go about this as not many people have tried it.

I'll guess I'll have to do some reading up and research on this. For now, I will be concentrating on this thread on romraider.

Getting started on Methanol

Below is a log of 4th gear pull at 1.7 bar (Channel3 of my Blitz SBC-id Boost controller)using my base map for Water injection.




Some points to note:

1. The green areas show areas that I can add more timing (with methanol).
2. Though there is still knock, I think this is due to the higher MAFv which is reaching its max.

Some changes I'm trying is to increase timing in those green areas:

Base Map for Water Injection

Since my last post, I've been doing several rounds of tuning to get a good base map for water injection and I think I've got it. This map is named "20081208_timing_tipin_fuel.hex".

With water injection, I've found that I can go as high as 1.5 bar of boost with no knock. My IDC is about 80% which I feel is quite safe. At 1.7 bar of boost, I do not have much knock. My max IDC will hit 95% occasionally.(see below)



No methanol needed. Only slight knock during normal driving which occurs vey rarely.

The object of this timing (part 2) is to go as far as possible with just water injection.

The only changes I did to get to this base map is to change my open loop fuel table (run leaner to 11.2 in high load) and my timing (increase).

Getting started with tuning timing for higher end

As mentioned in my earlier post, I will be usiung the starting base ROM from 20081019_advance-no-knock.hex. I will name this base rom as 20081120_BASE.hex.

This base map works well with no knock on Channel 1 on my SBC (boost 1.3 bar)
On Channel 2 however, there is some knock on the higher RPMs (boost 1.5 bar)
There is no knock during normal driving but after flashing there may be some slight knock. It will resolve itself aftera few days of driving.

No water/alcohol injection is needed.

The first step I did was to set my timing changes as follows:
1st area 0.2 x 2

2nd area 0.2 x 2

3rd area 0.2 x 3

4th area 1 x 3

Final changes:


Target AFR changes:


Tip-in changeas:
5.2 onwards 50x 4
7.5 onwards 50 x 4
9.8 ownards 50x 3
12.3 onwards 50 x 3
14.6 ownards 50 x 3
17 onwards 50 x 4
19.5 owwards 50 x 1


These changes created knock (probably due to the increase in timing):


I considered increasing my target AFR and also my tipin but then.. I thought, why use water injection (since it is already installed and running). When I did that, there's no knock. In fact I even reverted back my tip-in and target AFR. i.e. only include the timing changes in this post and did another 3rd gear pull - NO KNOCK!!

I drove back on the highway and did some enthusiastic driving at above 110km/h with boosting and found I have knock. I noticed that it happened at 20% throttle, maybe I can increase my tip-in in those areas:


I'll try that out and post the results on my next blog (probably increase my timing too + plus methanol heehee). My ROM for this round of changes is 20081128_timing_boostlimit_forwaterinjection.hex

Perhaps, I will try how much timing I can add with water injection before starting on methanol. That way I have a map that I know is safe with water but without methanol.