Project S2000 – Part 15 – Making a More Responsive Drivetrain

,

It’s not a perfect comparison, but not too bad.  Let’s say the starting point for comparison is at 0.1 seconds as that’s where the two lines cross each other.  The new lighter combo gets to 5000rpms at 0.32 seconds whereas the old stock combo takes until 0.40 seconds.  So the interval times are 0.22 seconds versus .30 seconds.  So the new lighter combo reduced the time to rev up by about 27% (0.22/0.30 = 0.733).  That’s pretty damn close to my estimate of 30% (actually calculated to 28.6% but I rounded up to 30% due to significant figures, estimated clutch mass, blah blah blah)!  Hey, basic math and physics work sometimes; math is cool, stay in school (I should trademark that or something).  There is one other thing to take note of in the graphs and that is the slope of the line when the throttle is blipped.  Notice how the new setup accelerates harder as the throttle is blipped as indicated by the steeper slope of the line.  More on this in a bit.

I made this to show a bit more of the test conditions.  As you can see, I did blip a little harder with the new test (TPS hit almost 90%) compared to the old test (~70% TPS), but the MAP voltage is nearly identical indicating the same intake manifold conditions and therefore power.  The intake manifold air temperatures were within 4 degree Celsius of each other too which is insignificant.  Of course, these graphs are made possible by the Hondata Kpro software that allows you to export the data to Excel.

While the car was up in the air with the transmission out, it seemed like a good idea to do the engine mounts too.  The stock engine mounts allowed enough movement to mess up my shifting.  I noticed this at Streets of Willow where I needed to shift from 2nd gear into 3rd while going through a left-hand sweeper.  The lateral G forces where enough to cause the engine to shift a bit.  So when I went to shift from 2nd into 3rd, I got jammed up between 1st and 3rd instead of sliding into 3rd.  This sometimes would also happen whenever I tried to shift as quickly as possible as the engine would be torqued up when at WOT and shifted a bit.  So what’s the cure?  Stiffer engine mounts of course.

Hasport needs no introduction when it comes to Hondas and they recently came out with an engine mount kit for the S2000.  I’m very glad they did because I was not keen on the other available options.  The Hasport mounts consist of powder coated metal brackets along with the billet machined bushing mounts.  It’s a shame the mounts are hidden because they sure are pretty.  The Hasport mounts can be had in four durometers: 62A, 70A, 80A, and 94A.  As my car is nearly stock power, I opted for the softest 62A durometer.

These are the stock engine mounts which use cast aluminum brackets with big rubber bushing things.

The passenger-side Hasport mount side-by-side with the OEM mount.  When installing the Hasport bushing into its metal bracket, make sure to use a lot of lube to allow the bushing to slide in more easily.

Mounts generally tend to break-in a bit, but as of right now, they add quite a bit of vibration even though these are of the softest durometer.  This is mostly noticeable at idle.  It’s not hard to imagine why when you look at just how much rubber is used in the stock mounts.  Once above idle speed, you barely notice the added vibration.  An interesting effect I had not expected was the change in sound of the car.  It actually sounds sort of like the car has a mild air intake or exhaust.  My theory is that the front subframe acts like a big speaker.  The Hasport mount connects directly to the subframe with an aluminum mount whereas the stock engine mounts use the super big rubber bushing to dampen the transmission of vibrations.  It’s kind of neat as the car now has a throaty sound to it.