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Discussion Starter #1
Hi, i´m running a D16a9 with hastings high compression domed pistons, i´m going to replace my rods (stock), for some eagle ones, what i would like to know, is if i can assemble a turbo, in a zc with this pistons, or do i have to replace the pistons for some low comp ones? I´m runing 11:1 compression, if I run a turbo will the pistons take it? here in portugal we use 98 octane fuel or even 100 octane. Here in portugal is not a very comon mod yet, so we dont have a lot of information.
Tks
 

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crap! dude if you have 98-100 available easily, then you should have no problem.

but lower compression IS easier to tune, and you CAN run more boost wihtout dangers.
so if you wanted to you could just slap a thicker cometic headgasket on there to lower the compression without having to actually get all new pistons.

HOWEVER if you're going to swap the rods that'll require just as much work as putting in new pistons anyways..

just something to think about.
 

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I am running 11.1 w/ built motor @ 8lbs right now on pump Gas :)
 
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Discussion Starter #5
I'd go for it, but since you probably measure the octane differently in Portugal I'd be a little more conservative with timing.
 

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i'd double up on the stock head gaskets, as long as you have head studs, that should lower it some. Drink some porto for me.
 

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^^^what the heck are you thinking?

anyway if you want to high compression and high boost is what all the high HP honda's are...just take a damn good tuner
 
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Discussion Starter #8
I´ll drink some Porto for you ;)
I´m using high comp pistons because I was doing an aspirated preparation, but after earing some opinions i changed my mind and i´m going for turbo.
My pistons are new so i just wanted to know if i had to replace them.
 
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hahaha rotory20 that dam giraffe sp?) cracks me the heck up!! hahaahahaha
 

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like some have said you just needa good tune and watch it closely

and some ppl said with lower comp you can run higher boost but i always heard that with higher comp and lower boost u can make the same numbers as low comp and high boost
 

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Rexinre said:
I am running 10.2:1 C/R and 15psi on pump gas! Its fine, just need a good tune and somekind of good engine management!
Damn! What kind of power are you making with your setup?
 
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Discussion Starter #16
How does your SC's manifold work? Is it a stock one or is it modified so that the SC is turned to directly shoot into the runners?
 

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Rexinre said:
Untuned I am guessing about 250-280. When I am done fine tuning I am shooting for 310ish.
Im @ 10.5 I am thinking about turning mine up too 15 or until detonation tomorrow when I retune it :)
 
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Discussion Starter #18
What is really funny is lower comp and power adders make more hp than high comp.

Somethings I learned to show what I mean.
What does nitrous do?
Throws in alot more oxygen so you can burn alot more fuel causing you to make more power.
What does boost do?
Throws in alot more oxygen so you can burn alot more fuel causing you to make more power.
What does lower compression on a boosted setup do?
Allows more room in the chamber for air, allowing you to burn more fuel and make more power.
Case in point:
I was running and sir2 motor with 2 layer head gasket (previous owner) @ 9 psi. Fully dyno tuned at 250 whp. Ran 13.6 @101 with a 2.2 60'. After a day of bad gas, I had to rebuilt it. I put in srp pistons 8.5 comp and eagle rods. Nothing else changed. Went to the dyno and under load in second I started boosting...2 psi 3 psi a/f went to 14.5 when on the exact same setup with higher comp was at 12.3 - 11.8 a/f ratio. I was like wtf I thought I would need less fuel. Anyways in the end I made 20 more whp and ran a 13.3 @106 with a 2.3 60'.

My friend had been telling me this before, but I had no idea how it would work. he explained it as:
take a 5 gallon propane tank(full) and a 50 gallon propane tank with 5 gallons in it, which one will make a bigger explosion?
The 50 gallon cause there is more air in with the fuel.

just my .02
 
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Discussion Starter #19
You're saying that at 9psi on 8.5:1 you made more power than 9psi on 10:1 or whatever stock is? I find the hard to believe. The reason why high comp on supercharged cars is better is because you can't keep cranking the boost up like on a turbo. SC's become inefficient much more quickly. I find your first claim hard to believe.
 
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Discussion Starter #20
Yes that is exactly what I am saying, I went from 10.7:1 to 8.5:1 with everything else the same and made 20 more whp, lower et and higher trap speeds. I changed nothing else on the car. I even used the same tune (but I had to add more fuel). The fact that I had to add more fuel proves the point because that is what power adders enable you to do, make more power by burning more fuel.

Did I find it hard to beleive too...yeah first thing I said was WTF. But I have had friends into boosting v8's that have been telling me this for years, I was just closed minded. How could lower compression make more HP. Because it has more room to pack air in, enabling you to burn more fuel. More air, more fuel = more HP.
 
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