eDm cRxXx

Cool project.

What did you use to measure the CC? I have found out that many of the cheap measuring kits are very inaccurate.

Have you milled the d16 heads this much before? Is the head still strong enough to avoid warping and such?

MadMod: that was on a d15 right? The extra stroke of the d16 helps the compression ratio quite a lot.

Charlie Moua

iTrader: (3)

in for the results

Presidential_Detail

Interesting build, I was pretty close to building a 17:1 D series several years ago. Ended up selling my shell before I complete the motor and bought an s2k.

Topoyiyo

A few pic

98vtec

?

Madmood

I can tell you right now. Those cheap p29's are not going to like that 17 to 1 for too long at all. I dont care what kind of magical fuel you use. Why not spend a little more now on an actual piston. Instead of more later.

Also, you are probably going to have to machine the header flange down or it wont fit. Angle milling ftw!

Dont listen to me tough. I am nobody.

Topoyiyo

I've milled d16 heads right to the intake seat before like I did this one and it ran great. The only thing I am a little concerned about are those cast pistons

Topoyiyo

Cam Specs

Aquafina

iTrader: (3)

The headgasket data on the calculator is wrong, FYI.

Rocket

Did that head get a valve job?

opc

ahhhh, i would pay to see this running for more than a week... a off the shelf cam, 17:1 comp, and cast pistons...

:facepalm:

on the bight side, i'm not seeing stage 2, or stage 3 anywhere.... so atleast you're 1 up over the scooby guys

jimmysxxl

17:1 with that Cam won't be tunable.

eDm cRxXx

Thanks

E85? Plan on measuring fuel consumption?

High compression pressure (high CR and little overlap) is important for low fuel consumption, though I think you might have to retard timing so much that you will down on power compared to lower compression.

I have for a long time wanted to built a "high" CR Turboed D13 to see how good fuel consumption I could get on E85. downsizing+e85+highCR.

Rocket

Why dat.

Mr. Dabolina

This is going to knock, ping and detonate itself into oblivion. You killed all of the quench area on the head. I see a lot of combustion chamber hotspots happening.

If it even holds together youre going to end up pulling so much timing that youre probably going to be really disappointed with the hp numbers.

eDm cRxXx

haha, it actually has a much bigger squish area now than stock, and also the squish distance is better (about the same as the thickness of the headgasket).

Also the edge towards the valveseats are probably quite round. But I would probably port the sides of the CC a little bit so that it follows the cylinder perfect (although that would loose a tiny bit of compression).

Everything is "tunable" for a good tuner, but you might be somewhat correct about the last statement (especially before vtec is activated).

92civiceg9gsr

That much compression is going to bust those cast pistons regardless of fuel used and amount of tuning. Your also gonna need more airflow than just a "worked over" head and off the shelf cam. A bigger cam will help to drop the dynamic compression ratio. You probably would make more power with ~14:1 static compression and the rest of the stuff you've got.

jimmysxxl

Unless race fuel, and with so high Dynamic compression as some other people have stated he will have to pull lots of timing back and run richer than optimal to avoid det. and be on a somewhat safe side imho

Mr. Dabolina

Youre basing this on the CR calculator that obviously has issues. It shows the piston coming proud of the deck on the second calculator picture he posted but not the first with the same bottom end specs.

Look at a stock Z6 head. The quench areas arent flat with the head surface. I can't prove anything since I can measure anything but it looks like the quench distance is going to be way tight.

The edges definitely need blended in. Sharp edges make hot spots.

eDm cRxXx

Agree on the edges, Espicially those on the sides of the valves. Like I said I would port it out so that it follows the cylinder.

According to zealautowerks the pm7/p29 have .5 or 1mm lower compression heigh than z6, a6, and most other d16 pistons, so in theory they should sit below the deck.

I once installed PM7 pistons on a d15 block, and id did not come proud of the deck on that engine.

Also, I am pretty sure the owner will make sure the pistons don't come proud of the deck. He does not sounds stupid :p

I have actually run PCT pistons way out of the block with a pr3 head welded so there was not extra quech distance (like here). Don't have the numbers here, but it was extremely tight. The engine ran for one full season of rallycross racing without any issues, actually it ran very good to. Although this is off course not recommended.