10.5 CR on pump gas?
#1
Honda-Tech Member
Thread Starter
10.5 CR on pump gas?
Hey Guys,
In looking for pistons for my D16Y8 and I would have loved to have kept the stock CR of 9.6:1 but I'm not finding any aftermarket pistons that do that. My choices are Vitaras at a very low 8.4:1 or aftermarket 9.0:1 or 10.5:1.
From playing around with Mustangs for many years I know I don't want lower CR. It kills throttle response and gas mileage and mpg is one thing I really love about this civic and don't want to ruin. So it's looking like my choice is 10.5:1. Do I need to be concerned with that high a compression on 91 pump gas (premium in KC)? I assume I can just pull some timing to compensate for the added CR.
I'm only at 10 lbs of boost right now too. Also if it ever does become an issue one day when I want to add a little boost I can always run water/meth injection to kick the octane way up if needed. I run it on the Cobra and it works fantastic.
In looking for pistons for my D16Y8 and I would have loved to have kept the stock CR of 9.6:1 but I'm not finding any aftermarket pistons that do that. My choices are Vitaras at a very low 8.4:1 or aftermarket 9.0:1 or 10.5:1.
From playing around with Mustangs for many years I know I don't want lower CR. It kills throttle response and gas mileage and mpg is one thing I really love about this civic and don't want to ruin. So it's looking like my choice is 10.5:1. Do I need to be concerned with that high a compression on 91 pump gas (premium in KC)? I assume I can just pull some timing to compensate for the added CR.
I'm only at 10 lbs of boost right now too. Also if it ever does become an issue one day when I want to add a little boost I can always run water/meth injection to kick the octane way up if needed. I run it on the Cobra and it works fantastic.
#2
Honda-Tech Member
Re: 10.5 CR on pump gas?
10.5 to 1 is still not very high. If your gonna boost it just make sure they are forged pistons. The weak point in the single cams are the rods. im running 20PSI on pump gas right now, so with your 10 you should be fine ( depending how much power your making off that 10 PSI ). I dont get how you think lowering your compression will kill your MPG? Im running 9.0 to 1 and still get almost 32 MPG outta a 370WHP B16, MPG is all in how lean you run at half throttle. basically its all in the tune
#3
Honda-Tech Member
Thread Starter
Re: 10.5 CR on pump gas?
Thanks for the info. If these motors will take 10.5:1 with no problem on pump gas then all the better.
Oh that is absolute fact. Not only is it in every piece of automotive literature but I've found that out first hand many times playing in the Mustang world. Simple physics, less compression makes less power on the same amount of fuel and requires more fuel to power the car along. The affects I'm sure are a lot less pronounced on a small 1.6 motor vs the larger v8s but it's still going to happen.
Not entirely true. CR plays a big factor in the motors efficiency and of course mpg. There will be a point in leaning out the A/F ratio to much to where you're getting counter productive because it's requiring more throttle (and more gas) from the driver to keep the car cruising at X mph.
Not to mention cruising at very lean AFs can be bad too. Heat is one major concern.
Greg Banish explains these concepts very well in his books. If you're not familiar he's an OEM calibrator for GM and does a lot of aftermarket performance tuning and training classes. I highly recommend his books and DVDs if you're into tuning.
Not to mention cruising at very lean AFs can be bad too. Heat is one major concern.
Greg Banish explains these concepts very well in his books. If you're not familiar he's an OEM calibrator for GM and does a lot of aftermarket performance tuning and training classes. I highly recommend his books and DVDs if you're into tuning.
#5
Honda-Tech Member
Thread Starter
Re: 10.5 CR on pump gas?
I got my threads crossed but while calling Real Street to inquire about their pistons they highly advised I do not go with the 10.5:1. They said unless I'm running C16 or E85 I'll be loosing HP because of the amount of timing I have to pull. He said honestly loose a little mpg and go with the 9.0:1 and I'll make a lot more HP on the high side.
Last edited by MalcolmV8; 09-13-2012 at 06:09 AM.
#6
Moderator in Chief
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Re: 10.5 CR on pump gas?
sigh, everyone has different opinions. I think 10:1 compression is very mild. You see plenty of stock block Hondas with similar or higher compression using pump gas. Cylinder pressure makes power and that is relative to boost and static compression.
Last edited by Muckman; 09-13-2012 at 05:58 AM.
#7
Honda-Tech Member
Thread Starter
Re: 10.5 CR on pump gas?
If the 9.0 pistons are more boost friendly and the motor will make more power I'm open to that too. Like I said looking for feedback from guys that have actually done this.
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#8
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Re: 10.5 CR on pump gas?
10.5.1 isnt high compression at all. That **** is super mild, especially with it being 2012 and all the tuning advancements and available knowledge etc. 10.5.1 on pump gas should be a breeze with a good tuner. I dont know why people still insist on doing these 8.8.1 -9.1 compression setups................ why not get that compression up where it needs to be ladies.
#9
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Re: 10.5 CR on pump gas?
I am running Arias pistons with a 10.2 to 1 compression myself. My engine is running now but just naturally aspirated until I can save up the rest of the money to finish her up. Feel free to check out my build thread if you wish sir.
#10
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Thread Starter
Re: 10.5 CR on pump gas?
10.5.1 isnt high compression at all. That **** is super mild, especially with it being 2012 and all the tuning advancements and available knowledge etc. 10.5.1 on pump gas should be a breeze with a good tuner. I dont know why people still insist on doing these 8.8.1 -9.1 compression setups................ why not get that compression up where it needs to be ladies.
As for tuner... well it's just me playing with my project car so that maybe something to consider. If 10.5:1 is territory with little room for error and tuning excellence I might be better off with a little less compression.
#12
Honda-Tech Member
Re: 10.5 CR on pump gas?
Go 9.5 to 1. You can still manage 30+ MPG and make great power. You mentioned water meth, that will help you out a lot as well. My tuner ( TrackForged ) actually said I should went with a 10.0 to 1 piston... Ohwell
#13
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iTrader: (1)
Re: 10.5 CR on pump gas?
Again im not here to dispute just adding my little .02. I would sure rather have a 10.1 compression setup than 8.8.1. Makes for a dog out of boost and casual driving around town. Its bad enough our cars make no torque in the first place......
#14
Honda-Tech Member
Re: 10.5 CR on pump gas?
I agree with you, but in his original post 10.1 isnt in his options of choices he has found
#16
Honda-Tech Member
Re: 10.5 CR on pump gas?
10.5 to 1 is still not very high. If your gonna boost it just make sure they are forged pistons. The weak point in the single cams are the rods. im running 20PSI on pump gas right now, so with your 10 you should be fine ( depending how much power your making off that 10 PSI ). I dont get how you think lowering your compression will kill your MPG? Im running 9.0 to 1 and still get almost 32 MPG outta a 370WHP B16, MPG is all in how lean you run at half throttle. basically its all in the tune
#17
Honda-Tech Member
Re: 10.5 CR on pump gas?
this is why u dont want 9.0to 1 most of the b16s i tune make 400 plus whp at 20 psi and all run 10 to 1 plus comp we have a bone stock b16 with only arp headstuds makeing 407whp at 19psi so if i where u i would go 10.to1 or higher and run a few pounds less boost. not to mention ur spool sooner with more comp.
#18
Honda-Tech Member
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Re: 10.5 CR on pump gas?
If I'm reading all your responses correctly I think almost everyone on this thread is in agreement that 10.5:1 is the better way to go.
#20
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Re: 10.5 CR on pump gas?
#21
Honda-Tech Member
Re: 10.5 CR on pump gas?
With water meth you can run a lot more then 20PSI on ur Y8. What size of turbo are you going to be running?