if i got my z6 bored out to 1.8 and replaced the piston, how much will the hp increase?

 

gains would be very noticeable. Depending on ur bolt ons u could see up to 20 hp more, but to get 1.8 litre u would have to bore to 79mm i do believe. your stock cylinder walls couldnt handle it, and i dont think that the darton sleeves can take that large of a bore. so how do u plan to accomplish this?

 

save your money for some neons or for a bodykit jk

 

kroh your a ricer at heart

 

Go with some flat top pistons, some bowl work on the head and a new cam. Then get it tuned, if you get around 11.5:1 compression you will see alot of HP gains.

DocManakos@aol.com

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by surrealcivic17 &raquo;</TD></TR><TR><TD CLASS="quote">save your money for some neons or for a bodykit jk</TD></TR></TABLE>

i :heart: neons!!!

 

WIthout additional headwork I think you might b e alittel dissapointed in the gains.... of course since you'll still be using normal sized combustion chambers the CR will be increased quite a bit.....might want to use a stronger head gasket. Get a dyno of it dude....I am curious to see what kind of modifications this will make to your powerband!!!

 

I was hoping to find someone who already has done it and had it dynoed. I'm really not sure you need much more head work done. Especially since this combination is a street/autocross set up, which is to recapture as much torque as possible and not really to gain more in your top end HP. You gain about 2% across the RPM band with every point you increase compression. So with flat top pistons you gain almost 2.5 points (going from 9.2 to 11.6:1) or 10% across the RPM band. But with that alone you increase torque like crazy, since you gain so much more vacuum. I forgot to mention that you will need to do some chamber porting to keep it down to that 11.5:1 ratio. Which means you can unshroud the values. If you add a nice camshaft to this, which gives you increases in both the primary and secondary lobes you have a pretty fast street/autocross car. I figure that a 10% increase in peak HP will gross you to about 150 HP (136HP @6700 JDM + 14HP) at the flywheel. With the other changes you will be at or over 160 HP but still at lower RPM's then a B16 DOHC VTEC (160HP @ 7600) (lighter also by over 100 lbs). Which means a faster street car. If you wanted to you could do increased head and exhaust work to up your upper RPM power. But if that's what you want you might as well go with a "B" series motor. Now look at this from a cost perspective, a JDM "D" Series D16Z6 motor $500, pistons $100?, head work $150, camshaft $125. Who knows most likely even cheaper.

DocManakos@aol.com