|We WPC treated our valve springs to help improve their life after we rev the piss out of them!
|A crank-scrapers.com windage tray helps strip the oil cloud off of our spinning crank and quickly return it to the pan. This reduces oil temp, oil consumption and we hope, frees up a little power.
With our pistons and rings selected, we decided to use Clevite Tri metal heavy duty racing main and rod bearings. We were sure to order H22 rod bearings. Tri metal bearings have a steel backing with a copper base followed by a lead with a high tin content for an overlay and a zinc top layer. We WPC treated our bearings as we have seen data from a reliable independent source showing that the WPC process increase the load bearing capacity of these bearings by 20% or more.
|Our Clevite bearings before we WPC’ed them and removed the black polymer coating!
|We WPC treated our N1 cams for less friction and longer life.
We also WPC treated our crank, bores, cams, cam caps and oil pump gears at this time. Read about how we blueprint oil pumps here! After a thorough cleaning, we reassembled the engine and broke it in by running at low load for 45 minutes on the dyno. In dyno testing at Road Race Engineering, our engine belted out 208 whp with 145 lb/ft of torque, an increase of about 11 hp over our previous motor. The power curve was a little less than stock at lower rpm as expected with the longer rods and broader across the top with less drop off of power past the power peak as expected. The torque curve was exceptionaly flat with the torque peaking at a high 7000 rpm, also as expected with longer rods. A longer rod should reduce high rpm friction and help volumetric efficiency at high rpm and hurt it slightly at low rpm.
|Our oil pump received WPC treatment and our blueprinting procedure.
Of course our new engine had a not so great leakdown number of around 6% when we did our dyno testing which is because it is not yet really broken in so the power should improve with some time. WPC treated engines take longer to break in as well as wear longer! When we ran our engine on the track, it felt much smoother and pulled very strongly to the fuel cut. The engine felt much more eager to rev and was strangely much quieter. Our car used to be the loudest car on the track but now was normally loud with the only difference being the long rod motor.
The engine felt less strained and less thrashy by a large amount. This stuff doesn’t translate well to dyno data but you could tell that the engine was under less stress. The engine is also mechanically quiet with none of the forged piston knocking noise typical of low silicon pistons. JE’s cam shape and perhaps the reduced slapping moment from the longer rods really works.
At Willow Springs raceway, our Sentra lapped at an amazing 1:32.6 seconds, more than 3 seconds a lap faster than any FWD SR powered car ever. Some of the improvements were attributable to improved aerodynamics and Hankook tires but the car flys. The gearing is currently way off and doesn’t match the powerband so with some gearing improvements and more suspension tuning, there is at least another second to be found in the car.
|A very Hondaish powerband. We are going to raise the rev limit to find more area under the power curve. 208 whp and 143 lb/ft of torque isn’t too shabby but we are going to do more experimenting with tuning and cam timing to try to extract more mid range out of our engine. With more break in the power should also rise, not bad for a simple low buck engine build.
In this case, it was only about $100 more (the cost of machining the rods) to build a long rod engine and we think it’s worth it. If there are more power gains after further break in we will report them. Overall this was a worthy experiment and we think you should not hesitate to try this on your SR20!