seriously, i don't think i've ever seen one post about head work on here. meanwhile, d-series.org has about twenty write ups for doing it in every configuration possible, including one wrote up by a drunk guy!
i just want to know what it is we are lacking. i've heard the port walls are thin in the series one l15, but what about the l15a7, since it shares the same motor with the cr-z and bisimoto somehow managed a crap ton of torque from that motor

 

Pretty sure the bismoto CRZ is machined, bored, ported, and sleeved. Idk if all of that would help on a NA L15 though.

Also the CRZ uses the LEA1 motor which isn't exactly the same as the L15, but apparently very similar.

 

The only 4 valve head I've ported was on a Honda R350 motorcycle and I had positive results... There is a thread on here and I believe on YouTube from Spoon 2 showing how they went about cleaning up the head for better flow... There isn't a lot that can be done so I'm leaving mine alone, for now anyway.

 

Ou how this will end up... Honda will come out with another l15 engine for the third gen and it will have the head we all need... Of course it'll be two grand for it... And will require extensive mods to the engine bay

 

The biggest problem with the 2nd Gen A7 head is the fact that the exhaust ports/mainfold are completely integrated and there is very little room to do more than polish up any casting flashes.

Tuning the port/runner/mainfold is where most of the gains would've been found. Be it NA or FI.

 

There is already a more tricked out L15A7 for use in an open wheel racing class called Formula Fit.Honda Performance Development, Inc. Proposes Entry Into FF ~ Honda Performance Development

 

All the internals (and head) for the FF fit engine are the same as the street car. They just add a dry sump, cable throttle body (off of a Honda boat motor) with an inlet restrictor (between the throttle body and intake) and a stand alone ECU (mapped by HPD) that is sealed, so no tinkering with the ECU. The engine builder is allowed to blueprint/balance, so far they haven't gotten more than 1-1.5 HP on their engine dyno from a blueprint (proving how good the engine is from the factory). No port work is allowed, no non-stock Honda parts allowed. If I remember correctly, with no restrictor, after a blueprint they got 134 HP, that is of course at the flywheel, as they use an engine dyno not a chassis dyno.

 

Still pretty cool news. Question, how easily is the remapped ecu integrated into a stock fit? Is it the same wiring harness??? Also how much???

 

Can't really be done, the ECU they use is basically a stand alone and not set up to run all the systems you'd find on the street car, and no the wiring harness is completly different, again it's just for the FF/F1600 cars.

 

Only race car drivers can get parts from HPD. Before they send you anything they need verification of the races you have participated in.

 

Honda really only needs you to sign up and see what your racing in, you can tell them that you AutoX and have aspirations of doing more...that's what I did when I started the build but then I broke the rules and took the car much further than Honda would have wanted to be in competition with the Mazdas and Sonics.

There is a way of simply cutting off the manifold, and doing it that way...but that's why I ordered a head to see what can be done.

-Mark

 

What about the intake manifold? That curled up design seemed a bit wasteful since early manifolds had short runners to the plenum and therefore more response ( and higher rpm torque?)

 

Longer intake runners mean more torque, there's a guy in the EU who built a short runner, he lost power until he got to 5100, then he saw a net gain of about 14hp till redline. That's a bit off because unless your sitting in the vtech powerband (only when hauling) then it's worthless.

That is something that needs to be addressed, something that could be easily done with porting and what not.

-Mark

 

You only use vtec when hauling? Dude I live in vtec

 

LOL, yeah, I mean...it's funny you say that because the more I noticed it...the more I realized that I would hit Vtech almost every other light.

-Mark

 

It is strange that the people I have talked to with the Weapon R intake manifold have all suffered a drop in low end power up to 3500 to 5000 RPM... VTEC is activated at about 3500 RPM.... I'm hoping that the Weapon R manifold works well with VTEC that activates at lower revs and 10 PSI boost.

 

Sure as hell doesn't feel like 3500, just took one for a spin, feels like 4200...3500 seems like (in most Honda cases where vtech controllers engage too early) would loose power due to VE being simply to low at the pressures you need to sustain backpressures...but hey, if that's it then I learned something about this thing again!

-Mark

 

T_C is talking about the GD, it has an economy type of VTEC where the remaining 4 valves come into play upon VTEC activation. The GE VTEC engagement is at 5400 and is always using all 16valves.

 

There is a slight drop in power at the time of the transition at 3500 and a little surge at around 4200... Mahout made me aware of that a long time ago.. With the Hondata reflash for the KWSC high boost kit the VTEC transition is at lower revs.. At low throttle setting when trying to lower the decibels when in town there is a little surge in power when in 2nd or 3rd when the 4 out of play intake valves kick into play... Man! I need to get everything installed and back together on my Fit.. I can't handle the heat anymore or being eaten alive at night by mosquitoes .. If I could only be 30 years younger for a few days and not be distracted by sexual desires like I was at that age I'd have it back together yesterday... Then I can be distracted until I am old again.

 

Need to find a traveling circus/amusement park and one of those scary looking old woman in a booth that grants wishes.