a6 or vitaras? with my jrsc

andresdelsol · 10-02-2009, 07:33 PM

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which one will do better? a6 pistons (std) or vitaras(std)? i plan in a near future upgrade to direct injection of nitrous(100-200 shot)

engine: d16y8 with z6 head
h beans standar lenght
p&p
turbo cam( donno which one yet)
rc 310 cc injectors
walbro 255l fuel pump
jrsc 10 psi
50 shot (wet) of nitrous
hondata s300

Foowee · 10-03-2009, 03:13 PM

I'm a fan of vitaras.

I think they will be cheaper than a6's if you're using aftermarket rods. To use oem pistons with an aftermarket rod you have to pay someone to cut a groove in the wristpin hole to install c-clips or spiral locks.

rushi · 10-04-2009, 04:52 AM

I won't recommend/vote for either. I say flat-top forged pistons with H-beam rods. With JRSC I wouldn't want to kill the engine with low compression. I'd prefer it to be in 10-11 range. And with that big shot of N2O I wouldn't want to risk it with cheap weak cast pistons either. Do it right.

Foowee · 10-04-2009, 03:32 PM

Rushi is right about the compression dealio. You're intake manifold to ex. manifold pressure ratio will blow heat through the motor... no worries about back pressure n reversion contaminating the mixture. Supercharged setups are far less likely to experience abnormal combustion.

When you say turbo cam, do you mean one with overlap dialed out? From what I understand overlap and cylinder filling is directly related to intake/ex manifold pressure ratios.

I still say vitaras though. I actually say vitaras are the only pistons that belong in a stock sleeve forced induction d. A big shot of nitrous is basically more air. If the mixture and timing events are correct, it doesn't matter if you have "cheap weak(proven to hold 400+hp reliably) pistons".

Actually Rushi, go ask Scott about doing it right. He's spraying a big shot on "cheap weak cast pistons." He drives the car daily too.

So Andre with vitaras n a jackson on 10lbs. you'd probably make somewhere around 160-180hp w/o the bottle. Spray a 200 shot bam 360-400ish... if plenty of timing is pulled in the lower revs(on the bottle) I don't see how "cheap weak cast pistons" will cause any reliability issues.

It's easy to build a fantasy motor with someone else's wallet. In the real world we all got mouths to feed.

glenniz · 10-04-2009, 05:38 PM

Originally Posted by Foowee

Rushi is right about the compression dealio. You're intake manifold to ex. manifold pressure ratio will blow heat through the motor... no worries about back pressure n reversion contaminating the mixture. Supercharged setups are far less likely to experience abnormal combustion.

When you say turbo cam, do you mean one with overlap dialed out? From what I understand overlap and cylinder filling is directly related to intake/ex manifold pressure ratios.

I still say vitaras though. I actually say vitaras are the only pistons that belong in a stock sleeve forced induction d. A big shot of nitrous is basically more air. If the mixture and timing events are correct, it doesn't matter if you have "cheap weak(proven to hold 400+hp reliably) pistons".

Actually Rushi, go ask Scott about doing it right. He's spraying a big shot on "cheap weak cast pistons." He drives the car daily too.

So Andre with vitaras n a jackson on 10lbs. you'd probably make somewhere around 160-180hp w/o the bottle. Spray a 200 shot bam 360-400ish... if plenty of timing is pulled in the lower revs(on the bottle) I don't see how "cheap weak cast pistons" will cause any reliability issues.

It's easy to build a fantasy motor with someone else's wallet. In the real world we all got mouths to feed.

Wow!....a little on edge today bro?

The_Beave · 10-04-2009, 05:45 PM

Fowee is always edgy on teh forums. It turns people off, but the dude knows his stuff. I find it refreshing. LOL!

Why are you building a Y8 bottom end? That's not a great way to start off a build. But anyway . . .

Whack 2mm off the Z6 head and use the Vitaras. As much as I don't even like Vitaras, they do work, and whacking the head a whole lot will keep the compresion in a usable range. I just don't like the effing huge dish on the Vitaras. That makes it really hard to keep your static compression up, which is a very good thing on any engine. The good thing about the Vitaras are thier performance to cost ratio, and the fact that they do offer some good quench characteristics, especially if one whacks the head and uses an MLS headgasket. That will prevent a heck of a lot of issues with detonation.

Foowee · 10-05-2009, 09:11 AM

Originally Posted by glenniz

Wow!....a little on edge today bro?

If being on edge is the same as stating facts. I guess I'm always on edge...

And to add to what Beavis mentioned about milling, an adjustable cam gear should definitely be added to the build if you go messing with cam bore to crank bore distance.

One more thing Andre I think you meant to say direct port nitrous. I don't know of any direct injection nitrous kits out there...

swich · 11-06-2009, 01:51 AM

yo how did the motor run with the vitara's and JRSC

Cambi · 11-06-2009, 02:14 AM

Originally Posted by boosted civic

yo how did the motor run with the vitara's and JRSC

I can tell you that stock bottom end D15s wont take a 75shot. Be careful.

swich · 11-06-2009, 03:33 AM

im not looking at running nos

im running a d16a6 block and crank with B18b rod's and vitara pistons. z6 sohc vtec head and JRSC at 12psi.

there is little to no info on runnung a supercharger with vitara's some say yes some say no. i want to know how is ran before i go and skim 2mm off the head to bring up the static comp...

and im 6000ft above sea level