headwork vs. compression vs. intake manifold porting vs. displacement.....
Thread Starter
Honda-Tech Member
Joined: Apr 2000
Posts: 12,949
Likes: 8
From: Atlantis
headwork vs. compression vs. intake manifold porting vs. displacement.....
How are these things related?
Assume you have these cars:
1. Bone stock usdm itr.
2. itr with 12:1 compression, toda spec b's, etc
3. more extreme setup with spec c's 2.0L block, 13:1
4. Turbo boosting 14psi on stock block itr and slightly lower compression
What are the effects of headwork, compression, intake manifold porting, and adding displacement? Assuming tuned to the new mods.....
I'm wondering if stock itr will benefit from itb's and by how much... Same for say portflow headwork, ported skunk 2 im and runners, or adding displacement.....
Assume you have these cars:
1. Bone stock usdm itr.
2. itr with 12:1 compression, toda spec b's, etc
3. more extreme setup with spec c's 2.0L block, 13:1
4. Turbo boosting 14psi on stock block itr and slightly lower compression
What are the effects of headwork, compression, intake manifold porting, and adding displacement? Assuming tuned to the new mods.....
I'm wondering if stock itr will benefit from itb's and by how much... Same for say portflow headwork, ported skunk 2 im and runners, or adding displacement.....
Joined: Dec 2001
Posts: 836
Likes: 0
From: Canada
Re: headwork vs. compression vs. intake manifold porting vs. displacement..... (Black R)
I hope this answers your question:
Head work and intake port polishing are done mainly to reduce air restrictions hence increasing the air flow in and out the engine. More air in means you can dump more gas in, which gives a better "explosion" (more torque). More air out means the air/fuel mixture is less contaminated by the exhaust gas remaining in the cylinder.
Higher compression by itself is there to again give a better "explosion" of the air/gas mixture, giving more torque; up to a certain point (around 12.5:1 compression) you run the chance of detonation when using pump gas. Higher compression can also be use with aggressive camshafts generally to compensate for the reduction in dynamic compression caused by the longer overlap of the camshafts.
Increase in displacement obviously means more air/fuel mixture in the cylinder hence a bigger "explosion" and more torque.
If you combine two or more of these elements you will get more and more performance until you need to upgrade other mechanical components because they are now the wickest link.
How much will the car benefit from each set-up is hard to say. But for sure a spec C, 2.0l block with 13:1 compression will benefit a lot more from a headwork then a stock engine because it as the potential to flow a lot more air.
It's like the great header test that was done. Pretty much all the headers gave the same result because the stock engine could not flow anymore air. But we pretty much all know that on a more modified engine (flowing more air) some headers would start to be restrictive while others would still be giving good performance.
I hope I'm not to basic in my answer.
Head work and intake port polishing are done mainly to reduce air restrictions hence increasing the air flow in and out the engine. More air in means you can dump more gas in, which gives a better "explosion" (more torque). More air out means the air/fuel mixture is less contaminated by the exhaust gas remaining in the cylinder.
Higher compression by itself is there to again give a better "explosion" of the air/gas mixture, giving more torque; up to a certain point (around 12.5:1 compression) you run the chance of detonation when using pump gas. Higher compression can also be use with aggressive camshafts generally to compensate for the reduction in dynamic compression caused by the longer overlap of the camshafts.
Increase in displacement obviously means more air/fuel mixture in the cylinder hence a bigger "explosion" and more torque.
If you combine two or more of these elements you will get more and more performance until you need to upgrade other mechanical components because they are now the wickest link.
How much will the car benefit from each set-up is hard to say. But for sure a spec C, 2.0l block with 13:1 compression will benefit a lot more from a headwork then a stock engine because it as the potential to flow a lot more air.
It's like the great header test that was done. Pretty much all the headers gave the same result because the stock engine could not flow anymore air. But we pretty much all know that on a more modified engine (flowing more air) some headers would start to be restrictive while others would still be giving good performance.
I hope I'm not to basic in my answer.
Thread
Thread Starter
Forum
Replies
Last Post
DJ_SaNdOz
Honda CRX / EF Civic (1988 - 1991)
3
Mar 18, 2003 11:54 AM
