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HondaKyle · 01-23-2008, 06:38 PM

papa

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LeGeND4LiFe · 01-23-2008, 07:49 PM

It's a good question...with a thicker headgasket, in addition to having to run more boost to make the same power, other factors come into play.

I've heard running a thicker headgasket to reduce compression also reduces the oem designed squish area in the combustion chamber, which is important in promoting efficient "fast-burn" combustion characteristics and thus preventing detonation.

Would be nice to get an experienced tuner's thoughts on the subject.

Knightsport · 01-24-2008, 02:59 AM

You can run a given pressure level with a given compression ratio if you pay attention to your AFR's. You just want to make sure it stays Stoich.

LeGeND4LiFe · 01-24-2008, 09:25 AM

Quote:

Originally Posted by Knightsport

You can run a given pressure level with a given compression ratio if you pay attention to your AFR's. You just want to make sure it stays Stoich.

AFR at stoich in boost would burn up the pistons pretty quick. Tuning safely for high compression and boost have more to do with ignition timing, proper AFR in the 11-12s is a given.

Even then there will be a low margin of error detonation ceiling with a high static compression ratio, pump gas octane fuel, and boost at some point.

fred92htch · 01-24-2008, 09:46 AM

So, after reading all the responses, what I'm thinking is leave the stock HG, go low boost, and you don't have to crack the motor open = reliability, given that you get a good tune. This is considering 300 HP or so.

I may never want to go more boost, as a DD. If I do, then I will change the HG at that time.

Swags04 · 01-24-2008, 10:23 AM

PSi doesnt really have any relation to hp. Slap a smaller turbo on their and you could run 20psi if you want.

Thicker Headgasket = lowers compression, allowing more horsepower to be made from boost.

Firstoost · 01-24-2008, 10:45 AM

Correct, combustion pressure is related to horsepower. It comes down to the CFM that the turbo can flow to determine the power gains, not PSI. Just look at a turbo flow chart

I run 8.5psi on my gt2871r making 350whp which is fine for me on stock compression and i wouldn't even TRY to push it further. I beleive my car is VERY reliable, but i DO plan to use a 2mm HG to attain my Daily driven 400WHP and still retain the reliability i have now.

for the person starting this thread as it is VERY helpful to others who want to know these answers

GetawayInMoscow · 01-24-2008, 11:04 AM

You would be surprised how little difference the headgasket will make in terms of power output at 11:1 vs 9:1.

The headgasket is for peace of mind and to help prevent detonation. But in terms of how much HP you make per lb of boost, it's almost the same.

Evan's tuning has a nice dyno sheet up showing this, maybe I can find it...

m R g S r · 01-24-2008, 01:41 PM

Stock motor + e85 + trusted tuner should mean no problems reaching 400whp and DD'ing the car.

GetawayInMoscow · 01-24-2008, 07:58 PM

Yeah but then you need 1600cc injectors and have to run E85 all the time, which could suck depending on what part of the US you live in

Agent Zero · 01-25-2008, 03:51 PM

Quote:

Originally Posted by GetawayInMoscow

Yeah but then you need 1600cc injectors and have to run E85 all the time, which could suck depending on what part of the US you live in

Your fuel lines would have be the size of a garden hose. You would be envious of Hummer gas mileage.

Thanks for all the responses everyone.

kabaroo · 01-25-2008, 05:19 PM

Quote:

Originally Posted by Agent Zero

Your fuel lines would have be the size of a garden hose. You would be envious of Hummer gas mileage.

Thanks for all the responses everyone.

ehh i run e85 on my NA motor with 550cc's and i get about the same mileage as i did last season when i was on gas.. I was a bit rich on gas but e85 isnt that bad. Its price for the octane rating more than makes up for any mileage issues which shouldnt matter in building a car like this (to a degree).

Flite · 01-25-2008, 07:09 PM

Lots of misleading information in this thread....

m R g S r · 01-25-2008, 07:13 PM

Quote:

Originally Posted by GetawayInMoscow

Yeah but then you need 1600cc injectors and have to run E85 all the time, which could suck depending on what part of the US you live in

Okay you DONT need 1600's for 400whp on e85.

Quote:

Originally Posted by Agent Zero

Your fuel lines would have be the size of a garden hose. You would be envious of Hummer gas mileage.

Thanks for all the responses everyone.

WTF you talkin about?

Do some research, I was just trying to help and saying you dont NEED a HG, spend the extra time and $$ on a reputable tuner, not some half assed one.

Agent Zero · 01-25-2008, 10:14 PM

Quote:

Originally Posted by kabaroo

ehh i run e85 on my NA motor with 550cc's and i get about the same mileage as i did last season when i was on gas.. I was a bit rich on gas but e85 isnt that bad. Its price for the octane rating more than makes up for any mileage issues which shouldnt matter in building a car like this (to a degree).

I was trying to be funny man. sheesh lighten up. didn't you notice the

after my post?

Quote:

Originally Posted by m R g S r

WTF you talkin about?

Do some research, I was just trying to help and saying you dont NEED a HG, spend the extra time and $$ on a reputable tuner, not some half assed one.

Lighten up douchearm....

Agent Zero · 01-25-2008, 10:16 PM

Quote:

Originally Posted by Flite

Lots of misleading information in this thread....

Ok captain fabulous... please teach us the right way....

Brandon · 01-25-2008, 11:14 PM

To be honest given where you live, you'd be better off just going with low boost and a 2-3mm head gasket. I know it's a little less power but the safety net of not having to have perfect fuel mix is great for peace of mind.

Agent Zero · 01-25-2008, 11:15 PM

Quote:

Originally Posted by Brandon

To be honest given where you live, you'd be better off just going with low boost and a 2-3mm head gasket. I know it's a little less power but the safety net of not having to have perfect fuel mix is great for peace of mind.

Thats most likely what I am gonna do.

GetawayInMoscow · 01-26-2008, 01:46 AM

Quote:

Originally Posted by m R g S r

Okay you DONT need 1600's for 400whp on e85.

My point is you would need some BIG ASS injectors. Not to mention you have to live in a place that has E85 everywhere. Not to mention E85 SUCKS for everything EXCEPT track use.

HondaKyle · 01-26-2008, 01:49 AM

how about 700CC will be fine

kabaroo · 01-27-2008, 10:25 AM

Quote:

Originally Posted by GetawayInMoscow

Not to mention E85 SUCKS for everything EXCEPT track use.

explain please... cuz i disagree mucho!

Francesco · 01-27-2008, 11:13 AM

Quote:

Originally Posted by papa5murf

Here's the deal.

- If you daily drive the car and or are going to drive the car hard. Get the headgasket. (just for piece of mind).
- If you think you're going to want more power in the future, just get the headgasket now, so you can take it up to around 500rwhp without any problems. On stock compression, you're pushing the limits once you hit 380-400 or so mark.

thats basically what it comes down to.

unless you want to do it the right way and custom build a motor to lower the compression that way, but theirs really no need to.

01-23-2008, 07:49 PM	#27
LeGeND4LiFe Junior Member Join Date: Sep 2003 Location: NY Posts: 705	Re: Turbo S with and without HG.. have some questions (HondaKyle) It's a good question...with a thicker headgasket, in addition to having to run more boost to make the same power, other factors come into play. I've heard running a thicker headgasket to reduce compression also reduces the oem designed squish area in the combustion chamber, which is important in promoting efficient "fast-burn" combustion characteristics and thus preventing detonation. Would be nice to get an experienced tuner's thoughts on the subject.

01-24-2008, 02:59 AM	#28
Knightsport There can be only one Join Date: Oct 2001 Location: Arlington, TX, USA Posts: 27,465	Re: Turbo S with and without HG.. have some questions (Agent Zero) You can run a given pressure level with a given compression ratio if you pay attention to your AFR's. You just want to make sure it stays Stoich. __________________ As societies grow decadent, the language grows decadent, too. Words are used to disguise, not to illuminate, action: you liberate a city by destroying it. Words are to confuse, so that at election time people will solemnly vote against their own interests.-Vidal

01-24-2008, 09:46 AM	#30
fred92htch Junior Member Join Date: Apr 2002 Location: tx, usa Posts: 403	Re: Turbo S with and without HG.. have some questions (LeGeND4LiFe) So, after reading all the responses, what I'm thinking is leave the stock HG, go low boost, and you don't have to crack the motor open = reliability, given that you get a good tune. This is considering 300 HP or so. I may never want to go more boost, as a DD. If I do, then I will change the HG at that time. __________________ 02 Silver S2k, HKS, Berks, AUT plate 92 Civic dx hatch, JDM b18c, CTR cams, DC 4-1, home made cold air, Skunk2 IM, Apexi WS, Eibach, B&M fpr 93 Civic vx, stock, 69.6 best MPG 01 Pathfinder

01-24-2008, 10:23 AM	#31
Swags04 Member Join Date: Feb 2002 Location: Central, PA, USA Posts: 6,575	Re: Turbo S with and without HG.. have some questions (Agent Zero) PSi doesnt really have any relation to hp. Slap a smaller turbo on their and you could run 20psi if you want. Thicker Headgasket = lowers compression, allowing more horsepower to be made from boost. __________________ Nikon Equipped 00 GPW Honda S2000 'If it dont make money it dont make cents'

01-24-2008, 11:04 AM	#33
GetawayInMoscow Banne*d Join Date: May 2002 Location: Denver, CO Posts: 4,693	Re: Turbo S with and without HG.. have some questions (Agent Zero) You would be surprised how little difference the headgasket will make in terms of power output at 11:1 vs 9:1. The headgasket is for peace of mind and to help prevent detonation. But in terms of how much HP you make per lb of boost, it's almost the same. Evan's tuning has a nice dyno sheet up showing this, maybe I can find it...

01-24-2008, 01:41 PM	#34
m R g S r Member Join Date: Jun 2003 Location: NYC bitchessss Posts: 9,488	Re: Turbo S with and without HG.. have some questions (Agent Zero) Stock motor + e85 + trusted tuner should mean no problems reaching 400whp and DD'ing the car. __________________ Manhattan College Mech. Engineering Student 2002 S2000--485whp pump gas 2009 Si Sedan--DD

01-24-2008, 07:58 PM	#35
GetawayInMoscow Banne*d Join Date: May 2002 Location: Denver, CO Posts: 4,693	Re: Turbo S with and without HG.. have some questions (m R g S r) Yeah but then you need 1600cc injectors and have to run E85 all the time, which could suck depending on what part of the US you live in

01-25-2008, 07:09 PM	#38
Flite Join Date: Sep 2005 Location: Hertford, NC, USA Posts: 132	Lots of misleading information in this thread....

01-25-2008, 11:14 PM	#42
Brandon Life is Suffering Join Date: Feb 2002 Location: There Posts: 8,931	Re: (Agent Zero) To be honest given where you live, you'd be better off just going with low boost and a 2-3mm head gasket. I know it's a little less power but the safety net of not having to have perfect fuel mix is great for peace of mind. __________________ I'd rather be hated for who I am, than loved for who I am not. XBL- The Way of Stig We like for everyone to know about the good works we do anonymously. -Jay Leno

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