NO, this is not some overpriced Hondata shit!
First you have to get one of the tiny sensors, nipples are always prefered! This one is a 3bar, MPXH6300ACT1 (same as the -U, different package).
Then you RIP your stock sensor apart! Actually, be gental. Drill/grind out the brass things in the screw holes, then pop the case halves apart (Honda used a little glue). I now use a reamer/countersink on the bottom of the rivets to pop their heads off.
Bust out the dremel tool and go to town. Grind it down until you hit the plastic & metal. I also grind the little round lip around the hole on the slim case half, this lets the sensor fit in perfectly. I now use a 1/2" end mill to drill 6 spots - the 4 around the nipple are 3/16" below the case lip, the 2 near the connector are just about 1/4" - enough to expose the brass pads you'll solder to.
Gentally cut the long contacts - a razor knife will work, its just copper. Get your nog-o-meter to test that the 3 tabs by the connector no longer connect to the stock sensor element. Then check to see what contact goes to what. BTW if you look into the connector spot at the pins, its stamped "V___G___O". They are voltage-in, ground, and output voltage, respectively.
Then take your Ver-nog Calinog to measure the port width. You'll be enlarging the stock case's hole a bit. Mine was .119", which is a #31 drill bit.
Check to see it sits in nicely. It should be snug; if it's tight you can port it a bit, if its loose - well, hope your permatex fills it up.
Wire it up appropriately. I think this is MadMax's diagram; if the author wants to be a dick, lmk so I can make a better one. V=Vs, G=Gnd, O=Vout
Use some Perma-nogx Gray or similar to seal it up. DO NOT get any near or into the port - that's an easy FAIL waiting to happen. Then place a glob below it so you don't get it leaking into the case (pops out of hole). Its better that way. Just test fit it all a few times before you even crack that tube of silicone. I use permatex black now. I splooge a bit around it & on the soldered connections afterwards, then put a huge lump below the sensor.
Clamp it in a vise for a few hours to let the permatex set, then you can rivet it together. I used a 7/32" aluminum tube I found (my make-shift crackpipe), but this requires the steel inserts that surrounded the original rivets. A 9/32" pipe will work if you lost the inserts. 3/8" of an inch is the perfect length. The key is to flare the edges just right (rolling edges with a center punch), then use a bolt & nuts to get them secured tight. It's okay to skip this step, but at least put the 7/32" tubes in there. The screws will keep the sensor clamped just fine.
Completed. 3bar for ~29psi on the left, 1.75bar for ~11psi on the right. You can find complete 56mm D16 TB's for under $30, and the stock sensors for under $5 if you shop right. You can order the 2.5/3/4 bar sensors from digikey for around $16 to your door in most cases.
Part Numbers and links:(Mouser.com is usually cheaper)
(the P/N suffix 6T1 or 6U denotes how it's wrapped up and DOES NOT MATTER)
2.5 Bar:
Part # MPXH6250AC
http://www.digikey.com/product-detail/en/MPXH6250AC6U/MPXH6250AC6U-ND/9518253 bar
Part # MPXH6300AC
http://www.digikey.com/product-detail/en/MPXH6300AC6U/MPXH6300AC6U-ND/9518274 bar
Part # MPXH6400AC
http://www.digikey.com/product-detail/en/MPXH6400AC6U/MPXH6400AC6U-ND/1168412The sensor values:
2.5bar:
min = 0.204 @ 20 kPa (.2bar)
max = 4.896 @ 250 kPa (2.5bar)
"koeo" voltage = 1.86v (calculated)
3bar:
min = 0.306 @ 20 kPa (.2bar)
max = 4.912 @ 304 kPa (3bar)
"koeo" voltage = 1.63v (calculated)
4bar:
min = 0.200 @ 20 kPa (.2bar)
max = 4.800 @ 400 kPa (4bar)
"koeo" voltage = 1.19v (calculated)
ATM my coupe is rockin a 2.5bar in the stock housing, can you tell?? FYI if anyone has noticed, D's usually have the xxx-2500 numbers on the sensors, B's xxx-3000's, and I've seen some preludes with a xxx-4220 number. I like to use that to denote if a case has a 2.5/3/4 bar in it, although a small engraving below the connector never hurts.
At the time of this writing, a few people have hit 300's with the sensors I've made, one has made 430 or so, another in the low 500's. If they see this, they'll chime in.
VERY big thanks to Madmax who did the first write-up (I think, dun want to go over there), and honorable mention to the Grand Intraweb Wizard himself, Joseph Davis. He claims to have done this back in the 'old days'. Not that I don't believe him...