I searched and cant find the answer...I know its there I have read it before but im tired of looking. How many cc's are the combustion chambers of the 2.4 ld9 head? and how many cc's are in the 086 head? Thanks. They guy doing my machining wants to know.
Ok discovered the 086 is 48cc....still need to know the 2.4 head cc though.
apx 61cc. In the GM book it says between 60-62cc.... the 086 head is 48cc
What effect does this have on the compression ratio? if you swap an 086 head onto an LD9, do you end up with really high (more than 10.2:1) compression?
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What effect does this have on the compression ratio? if you swap an 086 head onto an LD9, do you end up with really high (more than 10.2:1) compression?
Generally Speaking about 1.5-2.0 full points. I've actual put the head figures for the Quad4 heads verses the LD9 heads, and found it to be about a 1.7-1.9 increase.
So for a stock 96-98 LD9 with a CR of 9.5:1 - with a Quad 4 (example 086) head the CR is bumped to about 11.2:1
And for the 99-2002 LD9 with a CR of 9.7:1 - with the Quad 4 head - the CR is about 11.5-11.6:1
But there are a few ways to reduce the CR back down a bit if you like - by using Lower Compression Pistons, or thicker head gaskets.
Yep 11.7 for me. My machine shop guy says he might be able to get it to 54 cc's which will give me roughly 10.7-1. which means when I rebuild the bottom end I can use 9-1 pistons(if it were a stock head) and have 10-1 hopefully without custom expensive pistons. Then I can still boost it and have the head with the huge ports.
The "086" is the head off of an '86 quad 4, right? I just wanted to clarify, b/c I've heard that the exhaust ports on that head were too large for a naturally-aspirated engine- NA engines need a little backpressure to run right. I'm sure it would be good for a boosted engine, though (esp. turbo) since a boosted engine will be most efficient (powerful) with zero backpressure.
Before anyone says it, YES, an NA car will run w/o backpressure, but it will usually run better with
some backpressure (but not too much...)
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Then I can still boost it and have the head with the huge ports.
with a 10:1 compression ratio? how much boost are we talking about here? What kind of fuel will you be running?
I think you should tell just about every early 90's LG0 that there motor is getting too good of flow out of the exhaust ports....
So do I put a worse flowing head on my GTZ to get more power...... I suppose I COULD take it one more step, should I put smaller LO cams in? Or maybe the 95 LD2 cams...... but then I would have to weld a stud on for the power steering pump drive wouldn’t I.......
Wow.
Chris
'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08
I dont know about the back pressure thing but I do know that those heads were the ones on the factory performance motors like the W41 which was NA. As for the 10-1 with boost isnt the ecotec 10-1 and people bolt on the GM supercharger kit all the time and the 2.4 supercharger kit with 9.7-1. Im not planning on any thing crazy....maybe like 8psi but thats far off.
Since this is already on chamber sizes and I don't want to start a new post to find this out.
I have been searching but can't find the chamber size of a 2200.
Also if I could find out the deck clearence.
Thanks alot.
toyotaz87 wrote:The "086" is the head off of an '86 quad 4, right? I just wanted to clarify, b/c I've heard that the exhaust ports on that head were too large for a naturally-aspirated engine- NA engines need a little backpressure to run right. I'm sure it would be good for a boosted engine, though (esp. turbo) since a boosted engine will be most efficient (powerful) with zero backpressure.
Before anyone says it, YES, an NA car will run w/o backpressure, but it will usually run better with some backpressure (but not too much...)
No I'll say that back-pressure is BAD BAD BAD and BAD. The effect you're talking about is exhaust velocity. No 4-stroke engine ever built - N/A or boosted - needs back-pressure. That is an old myth that continues to this day. It is common because it makes sense to people who don't understand aero/fluid dynamics. Back-pressure is nothing more than the result of restriction in the exhaust system.
Now the phenomenon that made people think that is actually exhaust velocity. At lower RPMs(including idle), exhaust flows better through a smaller pipe(and of course though a matching sized head port). Why? At lower RPM's the quanity of exhaust gases just isn't gonna be enough to fill a 3" pipe. The gases spead out and slow down. Of course the larger pipe is better at higher RPMs since the volume of exhaust is alot higher and so a smaller pipe would be restrictive.
To show you how this works first hand - get a straw and a peice of cardboard that comes in the middle of a roll or toilet paper. Blow lightly though both. Notice how much faster and better it flows though the straw? Now blow hard. Notice how much better it flows though the cardboard piece?
As for the headports in question - larger ports are gonna be a little worse for low RPM torque, but much better for high RPM HP - N/A or not. If the rest of your engine setup(esp the cams) support this - then you have a winner.
I've never heard of this "part throttle" before. Does it just bolt on?
Ronnie (the cavalier guy) wrote:Since this is already on chamber sizes and I don't want to start a new post to find this out.
I have been searching but can't find the chamber size of a 2200.
Also if I could find out the deck clearence.
Thanks alot.
I'll post the volume when I get home (don't remember off-hand), deck clearance is reportedly ~.024"
fortune cookie say:
better a delay than a disaster.
toyotaz87 wrote:What effect does this have on the compression ratio? if you swap an 086 head onto an LD9, do you end up with really high (more than 10.2:1) compression?
Compression calculator.
I've never heard of this "part throttle" before. Does it just bolt on?
Quote:
So do I put a worse flowing head on my GTZ to get more power...... I suppose I COULD take it one more step, should I put smaller LO cams in? Or maybe the 95 LD2 cams...... but then I would have to weld a stud on for the power steering pump drive wouldn’t I.......
What part of this:
Quote:
some backpressure (but not too much...)
didn't you understand?
The "NOT MUCH" part, maybe!!?
Read the whole post before you make smart@ss comments like this.
as far as what bastardking said, I forgot that not everyone likes low-end torque... and the idea, as i understand it, is not that you get more exhaust velocity at low RPM, it's got more to do with some sort of scavenging effect. and, as i said, a very small amount of backpressure. btw, do you have any proven research or anything? not to be a jerk, or anything, i just would like to get a better understanding of the whole fluid-dynamics thing.
toyotaz87 wrote:as far as what bastardking said, I forgot that not everyone likes low-end torque... and the idea, as i understand it, is not that you get more exhaust velocity at low RPM, it's got more to do with some sort of scavenging effect. and, as i said, a very small amount of backpressure. btw, do you have any proven research or anything? not to be a jerk, or anything, i just would like to get a better understanding of the whole fluid-dynamics thing.
You want ZERO backpressure...period...no if's, and's, or but's...nothing, nada, nilch. The scavenging effect is created by the previous exhaust pulse passing through the collector and "pulling" the next pulse out of the next cylinder by creating a vacuum in the runner (vacuum = opposite of backpressure). The higher the velocity, the higher the suction. As said before, any measured pressure which "increases" performance is due purely to the increase in exhaust velocity which accompanies a smaller pipe.
With a turbo motor, the scavenging effect is not applicable due to the pressure buildup in the manifold before the turbo. After the turbo, you want as little restriction as possible, because the less backpressure you have the more efficient the turbine will be.
fortune cookie say:
better a delay than a disaster.
OHV i hate to aggravate you because i am sure you are a busy man, but did you ever find out the chamber size for the 2200
Ronnie (the cavalier guy) wrote:OHV i hate to aggravate you because i am sure you are a busy man, but did you ever find out the chamber size for the 2200
You know, I went home and checked my files, and apparently I never recorded them. I did however post an image in this forum with the #s, but I have no idea which thread, and it hasn't popped up in a search
fortune cookie say:
better a delay than a disaster.
ahhh thats cool man, i thought maybe you had forgot. I got one of the GM repair manuals on the way. Maybe it will have the info tucked away in one of it's million pages. Then we can get the info back out to the community
Karo (Car Customs) wrote:apx 61cc. In the GM book it says between 60-62cc.... the 086 head is 48cc
I was going to say 62 CC when I check mine
-Aaron
www.TurboTechRacing.com
Performance Parts For Cavalier, Sunfire, Cobalts and More!!!
toyotaz87 wrote:The "086" is the head off of an '86 quad 4, right?
No...It is the head casting number ending in xxxxx086 such as the one sitting next to me that reads 22539
086
...and it is found on every DOHC Quad4 trim from 90-92
-
"Youth in Asia"...I don't see anything wrong with that.
