So for shitzngiggles, i decided to build myself a highcomp, noTEC, dirty D, just to see what all the hype was about. There really wasn't any hype, but i wanted to try some ideas i had floating around it my noggin.
A few years back, i ordered a set of 75.5mm p29 nippon pistons, before ever even having a honda. Well i scored a 91 crx si, for almost free, completely stock, save for a k&n drop in filter, and a turbulator POWERADDER!!! Having lots of spare d parts lying around, as well as some B parts (you'll see where this comes in later), i put together a bastard D.
here's the ingredients:
-A6 block bored to 75.5mm
-p29 nippon pistons, same as stock p29/pm7s (everyone's favorite!)
-A6 head, rebuilt, bronze exh guides, radiused valvejob, fully ported from Hayward performance, 10thou removed for straightening.
-A6 cam, reground by Colt cams, i chose the Tri-Flow 2
-stock crank
-bisi valve springs
-bisi v2 header (as much as i wanted to build one, i just didn't wanna! PS: i had to repair this thing twice, and the post-collector elbow was angled waaaaaay wrong, good thing i can TIG)
-b18c1 gsr rods (
)
-gsr rod bearings
-A6 main bearings and thrust washer
-Z6 head gasket
-ported/radiused oil pump
-act lightweight flywheel
-Z6 intake manifold, opened, ported, TB port matched to a 60mm B16a jdm TB, and an increased plenum volume
-OBD-1 conversion, tuned on Neptune, dyno'ed on dynacom POD dyno
You may be saying to yourself...
"Why the GSR rods? They're too narrow on the big end to work with the d crank!"
"What about piston pin size?"
WAAAAAAAHHHH!
I used the gsr rods to get the P29's to (nearly) deck height. With the help of a great machinist who wanted to try this out, we had the GSR rod small end rebushed with a steel bushing for the pressfit 19mm p29 wrist pins. I chose these rods as well for their greater bolt strength (9mm vs 8mm for the LS rods), and so i can say it's got B series parts in it. Plus i wouldn't have to deck the block and buy an adjustable cam gear (i'm cheap and dutch, what do you expect).
As for the rod side clearance: the small end width is the same(ish) between gsr/typeR rods and D16 rods.... they'll stay centered. Oh, and as for oil pressure probs, none here.
enough bla bla-ing..
PICS!
P72 gsr rods, p29 pistons...
all lined up, ready to check ring gaps
block ready
bump stick
Necessary block notching, not your regular Eagle rod notching... since the P72 rods have about 2mm more girth around the rod shoulder, the whole swing area needed clearancing. NOT FUN.
TDC, to the top!
head portwork etc
moar portwork
intake manifold, opened up
capped off, more volume, does it help? i donno
head studz, copper sprayed MLS gasket
rebushed P72 rod
parts awaiting assembly, note the bisi header. had to notch the front crossmember to fit in the crx
garage, bench, signed pornstar photos...
before and after dyno, i was rushed and just did some WOT pulls on turboEdit ng63 rom, but couldn't get driveability nailed down. It was running an open 2.5" exhaust at the overaxle, and had some cool resonant power bumps. I later finished the exhaust with a dynomax VT flapper muffler, and did a Neptune tune with OBD1. At that time, the dyno's speedo pickup drivebelt kept spinning off near redline, making a giant spike in power, like 430hp... so those graphs were useless.
I have 13,000km on this "beast" running 91 rocktane, close to the same gas mileage as stock.
enjoy!
phil