D13Y8

[Dodo Bizar]

For comparison, picture I took from D14A4 piston, the P3X. Not so good shot, but looks similar doesn;t it?



Ah darn it, new page, here I quote your post again:

some OE piston pics Joris:

[007]

they look identical indeed! then wonder what brings about such a drastic change in compression. the head? unlikely. code is P2A. despite that, the lower displacement engine netting higher CR is quite puzzling.

edit: just found here that the P2A head came in AUDM D16Y4 and cc volume is 32.4 cc
http://www.d-series.org/forums/naturall ... ost1350470

OT: this "mystery" engine is classic LOL!!
http://www.hondacivicforum.co.uk/viewto ... t=0#p93272

D13B7

* Found in:
o 1998-2001 Honda Logo 5D
+ Displacement
+ Bore and Stroke : ?
+ Compression : 8:1
+ Power : 150 hp (? kW, ? ps) @ 6800 rpm
+ Torque : 180 ft·lbf (? kg/m, ? Nm) @ 6500 rpm
+ Valvetrain : SOHC (4 valves per cylinder)
+ Fuel Control : Multi-point fuel Injection, PGM-FI

[007]

couldnt shoot a video today but did manage to get a VBox run in. by the end of the day, with some very unscientific tuning, managed to achieve 0-100 in 10..5 seconds from 14 odd seconds when I began with a stock Y8 map plus fuel trim of +15 percent.

here is a link to the VBox plot: http://gearheads.in/attachment.php?atta ... 1333791607

raw VBox file: http://gearheads.in/attachment.php?atta ... 1333792890

final numbers stand at:
0-100: 10.5 seconds
400 meters: 17.5 seconds
0-140: 20.5 seconds

power delivery and throttle response are very nice now. however, I am simply not able to understand why my adjustments worked.

my displacement is 18 percent lesser than a D16
injector flow rate 26 percent lesser than a D16
however idle stabilizes only when I increase the overall fuel enrichment by 15-20 percent.
also, Ive had to add 13* and 18* to the Low and High ignition maps to get good throttle response under load. havent heard any pinging whatsoever. I have a feeling I can advance ignition even more but didnt want to do that and risk anything before I got some proper equipment to see exactly what is taking place.

Joris, do my numbers fall somewhat in line with what you had to do for your D14Y8?

[Dodo Bizar]

I understand high rpms need more fuel, idle I don't know. I actually don't know how my maps compare to stock maps. But I do know it is common for idle to need rich fuel once something is a bit tuned. So perhaps camtiming right now is a bit of and therefore you need a bit more fuel to get it running properly? But I'm wild guessing here. Glad you got decent speed out of it. Is the Vbox hooked up to the VSS signal or is it an acceleration integrater?

[007]

I think it has more to do with the stupid stock 190cc injectors that Im running. those have a flat tip with two tiny holes whereas the 240cc injectors the map was designed to work with are different. so maybe pulsewidth vs flow is not as simple an equation as Im assuming.

the VBox is a GPS based device Joris. it has a very accurate 10Hz GPS engine that tracks speed changes and spits out movement related data. in the picture that I linked to above you can clearly see where I shifted gears and where VTEC engaged in first and to an extent second gear by looking for the little jumps and flat spots.

I meant to write a simple program that would take the raw 10Hz data and plot it like a torque curve [assuming torque directly translates to acceleration] but never got around to it. I need to put that back up on my list of things to do.

[saxophonias]

these numbers are almost identical to the ones of a stock d14a4 3door with 2 passengers inside. It is verified many times by domestic car magazines.

[sktaroins]

I wish I was on this forum before I rebuilt my engine to show..
but its the same piston I have ... But the piston that can carry more pressure is the better one .. I read it and saw it somewhere
I think at bisimoto.
Regardless , more pressure the piston can carry . Less are the chances for them to break.

[007]

these numbers are almost identical to the ones of a stock d14a4 3door with 2 passengers inside. It is verified many times by domestic car magazines.

thanks. now I have a reference.
I had clocked better than that in the previous configuration with the non VTEC head and stock ECU. mapping makes all the difference. I am sure I will be able to beat it with the right tune. I will be satisfied if I will be able to shave 2 seconds off all the times. 0-160 in 20-22 seconds would be sweet.
however, the catch is that I want to do this without throwing fuel efficiency to the dogs, so it will have to be a lot more precise than just dump fuel everywhere.

I wish I was on this forum before I rebuilt my engine to show..
but its the same piston I have ... But the piston that can carry more pressure is the better one .. I read it and saw it somewhere
I think at bisimoto.
Regardless , more pressure the piston can carry . Less are the chances for them to break.

you mean forged pistons? I had mine coated with a ceramic layer on top to protect the surface from the heat generated by the higher compression. the three times I took the engine apart, the coating has remained intact. these should hold up just fine.

[saxophonias]

Just for further reference they measure 0-1000m to 32.5sec and 156km speed

[007]

Just for further reference they measure 0-1000m to 32.5sec and 156km speed

interesting. my data tells me that I had covered 502 meters by the time I touched 140 in 20.14 seconds. I just ran some numbers and if I were to continue steady at 140 without any acceleration, it would take a tad less than 13 seconds to cover another 500 meters. accelerating constantly, it would probably take a couple of seconds less.

guess this is where the better flowing VTEC heads shine. I had similar experiences on the old non VTEC head too. if would get to 120-ish real quick but would start to run out of breath once wind drag became significant.