Numbers & Crush

The most common questions I get asked about the RSX is how much power does it make and what are the spring rates?

K20 horsepower figures are commonly known and all over the internet.  200 wheel horsepower is widely accepted for a naturally aspirated K20a2 with I/H/E and a good tune and torque is generally below 150 but relatively flat from 3K to redline.  My car dynoed at 194hp / 147tq with a big jump in power over the stock tune and a much safer AFR.

Spring rates are currently 10K front and 12K rear.  The metric conversion is basically x56 so the fronts are 560 lbs/in and the rears are 672 lbs/in.  Way softer rates than what the internet says you need to have to make an RSX work properly and softer than I would like for autox but it is a good choice for this daily driver.  Rear motion ratio is .590 and the front is close to 1 so you can see the calculated wheel rates are actually softer in the rear.  With minimal rear toe and normal rake the car has no problems turning but cannot be classified as eager or willing.  Steady state push and slow transitions can be helped with more spring rate and higher rear bias, but that can hurt power application and be detrimental on bumpy surfaces.  Higher spring rates are in my possession and more changes are planned.

In anticipation of rear spring changes, I modified the rear swaybar by crushing the tube further back and adding another adjustment hole.  Not the most beautiful thing, but when combined with an alternate LCA endlink mount it will give much more adjustment opportunity and better articulation.

The new billet aluminum swaybar brackets are much stronger than the generic steel ones. Video shows the only deflection is from the thin urethane bushings, however if you observe closely it looks like the bottom half of the subframe is flexing. Maybe time to revisit the full width ASR subframe brace again.  Modeling clay on the lower control arms tells me how much clearance to the swaybar arms.

Rear Swaybar, Again

  Watch the video above and you can see the steel rear swaybar mounting bracket flex under load.  Some research shows that this flex is a common problem when using these universal brackets and they are prone to break or tear when using high rate swaybars combined with aggressive driving.  Stronger aftermarket brackets are available in various designs and materials and I chose to buy a pair of heavy duty billet aluminum brackets from James Barone Racing.  Prothane 1 1/4" urethane bushings are included for use with a planned Speedway bar and I also picked up a pair of 27mm bushings to use with my current Hotchkis swaybar.

Extreme example of what can happen.

The subframe mounting surface for the swaybar brackets is not completely flat and I also need to add more space for shaft collar clearance so I got an ASR rear subframe brace to help the situation.  The ASR brace is a 3/8" flat aluminum transverse plate that sandwiches between the rear subframe and swaybar brackets.  Mostly bling but very popular in the Honda world and widely available at reasonable prices.

Must be defective?  The brackets hang over the edge by at least 1/4", so I swap it out for a different one.

Nope.  Only the oem bracket is flush with the brace, but even that one the bushing still hangs over the edge.

My original idea was to simply cut and drill some scrap aluminum to make the spacers but I thought the ASR brace would be a better fit.  It does look good and offers a little strength to the mounting surface, but please...   Back to Plan A.  I will need to add another 1/8" spacer when using clamping collars with a 32mm bar.

So why not just buck up and buy the complete ASR 32mm swaybar kit instead of messing around with these odd brackets, braces, bushings, etc ?

I am not convinced that the swaybar arms provided with the kit will clear the RSX lower control arms when installed on a lowered vehicle. I have noticed notched swaybar arms and lower control arm interference when using this bar design and with all the misinformation on the internet forums and crappy parts available I cannot take the chance on buying a $600 swaybar and not being able to get a refund or return when it doesn't do what I want or meet my expectations.  And if I need a different sized center section I am out another $125+. It is also advertised to pretty much not fit with any full length exhaust which means more money to modify the tailpipe, which I already have modified to clear my current Hotchkis bar.  Also, the arm endlink holes are positioned in a way that requires endlink length adjustments when arm hole changes are made. (See Karcepts for an example of how to do it better.)

Now I don't necessarily want more rear bar stiffness, but I like the Speedway modular design's wide range of adjustability and ease of use. Similar to the front swaybar I built, I am slowly piecing together a rear swaybar that will use the existing subframe bracket mounts. Will need to have custom shaped arms with enough curve to safely clear the LCA.  If I can ditch the rear muffler section a trunk mount swaybar would be easier because the arms could be straight and attach to the backside of the LCAs.

Oiling

   Well, my diagnosis of the PCV system being my cause of the oil ingestion and resulting smoke show and power loss is wrong.  The problem is the breather tube that connects between the valve cover and intake pipe. Previously the problem was only showing up mid-session at a ProSolo where the engine had time to cleanse itself before I could make a good diagnosis.  However, at the most recent CSCC autox the problem came back so I immediately removed the suspected intake hose when I got back to grid and found oil pooling.  Just for good measure I checked the PCV hose and catch can too but all was clean and dry.

  The problem hose and fittings require a 19mm ID hose so modifications to the hoses and/or catch can would be needed to fix this.  Instead, I bought another ebay special oil catch can with the proper sized fittings and hose.  More money spent- yes - but no need to screw around with reducer fittings or whatever.  Plus, I can keep the original catch can in the PCV circuit if I want.

The oem breather hose design with its integrated water bypass pipe loop needs to be retained and without lengthening the water hoses it is pretty much stuck near its original location at the valve cover.  Keeping it simple I add one straight coupler and complete the circuit with the provided silicone hose. I reuse the mounting bracket and hardware from the old pcv catch can.

Knowing now that the oil can do funny things within the block has me more concerned about oil pressure and baffling.  The RSX's only oil sensor is merely a pressure switch that tells the computer it is safe to activate VTEC (over 50 psi or so) or turn on the idiot light because the pressure is below 10 psi.  A simple aftermarket oil pressure gauge is an easy solution but it is not practical, easy, or safe to monitor a gauge while competitively driving.   Defi makes a gauge kit with a recall or memory feature, but the cost and complexity is not what I want just for one sensor.  The Hondata Kpro ecu is equipped with inputs that can monitor and datalog such critical items, but a new sending unit or transducer would be required to get the proper signal into the ecu.  Ebay wins again and I buy a 100psi pressure transducer and BSPT adapter.

The new oil sensor install and wiring is basic stuff and then with a few ecu setting changes I can monitor and datalog oil pressure.  Biggest drawback is that I lose the oem oil idiot light, but Kpro has some advanced settings with several different actions that can warn the driver and/or protect the engine under preset conditions.  

Wiring colors:  +5v Grey/Red,  Signal Purple/Red.  Ground Orange

Next is to datalog at autox and see how oil pressure is affected and the results will determine how soon a baffled oil pan is required.