piston question

[sblkcamaro70]

ok so i have been doing some research for a (down the road project) i want to turbo by d15b2 for a daily driver. i want to run unleaded fuel in my car yet so i need to bring the compression down. my question is i want to pu d16y8 pistons in. will they work or not, because i am not sure what honda does to stroke the d15 to make them d16's . i guess to put the question in easier terms to answer is, are the pistons the same(except for the top of the piston)?

another question i guess i can feed off this forum is how high of compression can you run if you still use 87 octane? how bout 89 octane? and 91 octane?

[YZ125rider21]

87 i wouldnt go any higher than 9.5 or so...going into the 10 compression is asking for pinging and detonation...and isnt d15 and d16 diff size bores if i am not mistaking...that is how liters are made i thought by the bore size and stroke...i could be wrong still learning this stuff

[turtlecrxsi]

With any turbo application I wouldn't go with anything lower than 91 octane. Newer turbo cars use advanced knock sensor technology which supposedly retards timing when low octane fuel is used and just makes performance suffer. I wouldn't trust that though. My wife freaked out when we went to California since all they have out there is 91 and she only uses 93. BTW, d16y8 pistons are like 9.6:1 cr I think...

[jeef]

and the bore size should be the same, its the stroke that is different.
I highly suggest you check out www.homemadeturbo.com and just read, lots and lots of good info there. However, if you go in and ask a lot of questions that can be answered with a search they will flame you hard.

[Hybrid1990crx]

Originally Posted by turtlecrxsi

With any turbo application I wouldn't go with anything lower than 91 octane. Newer turbo cars use advanced knock sensor technology which supposedly retards timing when low octane fuel is used and just makes performance suffer. I wouldn't trust that though.

I'm pretty sure any knock sensor is going to do that, even the ones from obd0 b16's. On any motor that requires a higher octane, if you put in a lower octane, its going to ignite much easier of course. So anything from carbon or just a highspot on the pistion is going to cause a hot spot which is going to pre ignite the fule before TDC on the compression stroke, which will then cause a knock. So yeah I would definetly trust that.

To get back on topic,

The diffence in most honda motors displacement is the stroke. So I know the b17 compared to the b16 is pretty much just a different crank allowing the extra .1 litre. So its probably the same on the d series as well.

Also look into suzuki vitara pistons, they come dirt cheap and drop your compression a TON. Do a search on honda-tech and you'll find a ton of info.