High Compression Engine Build
Sep 27, 2009, 11:39 AM
#31
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So to have the best balance of compression and boost, what is my best bet for a FP Red or Black Build? My guess is that I won't shift any higher the 8500 RPM's. With having the goal to run 9's, should I stay with the 2.0L or move to something larger like a 2.1-2.3L? I saw that Buschur is now building a 2.1L 10:1 compression engine. Any into of that motor with an FP Red set up?
With the Project White running 11:1 on a 2.3L, there had to be a lot of thought that went into that. I am a Drag Racer at heart and want the best combo that would most likely to put me in the 9's!
Thank you everyone for all your input on this subject. This is an area I know very little in and am injoying the information.
With the Project White running 11:1 on a 2.3L, there had to be a lot of thought that went into that. I am a Drag Racer at heart and want the best combo that would most likely to put me in the 9's!
Thank you everyone for all your input on this subject. This is an area I know very little in and am injoying the information.
Sep 27, 2009, 01:11 PM
#32
here a guy excited about e-85 and high compression. just made 533whp at 20psi on standard 35r. I dont remember ever seeing 9/1 motors do those numbers.
http://www.4g61t.org/forum/viewtopic.php?f=42&t=30736
quote
slowdsm, e85 let you get away with a lot of thing. rhys runs 14:1 on his car with e85. i have heard of 15:1 boosted on e85. 11:1 is actually too conservative. i think 12:1 is actually ideal for the street just in case you have to turn the boost down and run 89-93 octane pump gas until you get more e85. also with 12:1, you don't have to worry to much about clearances between the piston, valves, and spark plug. with a good tuning system, you don't have to run some rediculous boost to make nice horse power. traditional journal bearings and 360 degree bearing turbo are useful again because you not going to kill it because of the lower boost level.
the key to making power is to have an air/fuel mixture that is as dense as possible to create a combustion with the highest potential energy. people like low compression piston so they can have more control over ignition timing and boost to create more power. the draw back to low compression is you have to run more boost to make more power which. boost level above 25psi on a standard bearing will wear out the thrust bearing in the turbo pretty fast. at 30psi and above on a standard bearing turbo, you can expect a turbo rebuild pretty soon. at high boost on a low compression motor, you sill have to run race fuel or a fuel with a high octane value because the air/density is as high as a high compression motor/low boost setup.
http://www.4g61t.org/forum/viewtopic.php?f=42&t=30736
quote
slowdsm, e85 let you get away with a lot of thing. rhys runs 14:1 on his car with e85. i have heard of 15:1 boosted on e85. 11:1 is actually too conservative. i think 12:1 is actually ideal for the street just in case you have to turn the boost down and run 89-93 octane pump gas until you get more e85. also with 12:1, you don't have to worry to much about clearances between the piston, valves, and spark plug. with a good tuning system, you don't have to run some rediculous boost to make nice horse power. traditional journal bearings and 360 degree bearing turbo are useful again because you not going to kill it because of the lower boost level.
the key to making power is to have an air/fuel mixture that is as dense as possible to create a combustion with the highest potential energy. people like low compression piston so they can have more control over ignition timing and boost to create more power. the draw back to low compression is you have to run more boost to make more power which. boost level above 25psi on a standard bearing will wear out the thrust bearing in the turbo pretty fast. at 30psi and above on a standard bearing turbo, you can expect a turbo rebuild pretty soon. at high boost on a low compression motor, you sill have to run race fuel or a fuel with a high octane value because the air/density is as high as a high compression motor/low boost setup.
Sep 27, 2009, 10:17 PM
#34
A 14:1 or 15:1 boosted methanol motor is totally not the same as ethanol. They have distinctly different properties independent of octane rating. That aside, you can see the "edge" alot faster on a higher compression e85 motor. Lucas now has a 690whp FS635 setup on his 11:1 2.0L and it is obvious in the logs that it is at the edge based on noise. When the car goes back to the stock ECU we'll see what it looks like as far as if it was real knock or not (I have much to say on the AEM "knock" control but thats another thread). I think when we get to turbos that are in the 3586 range of airflow, they are so efficient that 29psi on pump with excellent timing isnt hard. I have run mine out to 32psi recently and it really looks like I can keep going if I didnt mind find the mechanical edge of the stock bottom end. I am sure we can run 13:1 on E98 without much of an issue, but what we do in a racecar versus what a "streetcar" is setup with are entirely 2 different things.
I am very much with David when he says that some of the best combos are not ultra high compression or "high compression" motors. Our 9:1 1G Eclipse seems to make alot safer power on the 4202 than the Evo does at only 10:1.
We have also found that the old hotrod rule of 4% per full point on a given setup holds true. The 3065 car mentioned at the outset made 633whp with 11:1 at 32psi versus the 580ish it made the year before at 9:1. There were some other changes made with respects to reciprocating mass that gave is some additional power as well as a cam change that later got us to 640+ before we were once again out of fuel.
I am very much with David when he says that some of the best combos are not ultra high compression or "high compression" motors. Our 9:1 1G Eclipse seems to make alot safer power on the 4202 than the Evo does at only 10:1.
We have also found that the old hotrod rule of 4% per full point on a given setup holds true. The 3065 car mentioned at the outset made 633whp with 11:1 at 32psi versus the 580ish it made the year before at 9:1. There were some other changes made with respects to reciprocating mass that gave is some additional power as well as a cam change that later got us to 640+ before we were once again out of fuel.
Last edited by JohnBradley; Sep 29, 2009 at 11:05 PM.
Sep 29, 2009, 09:33 AM
#37
A 14:1 or 15:1 boosted methanol motor is totally not the same as ethanol. They have distinctly different properties independent of octane rating. That aside, you can see the "edge" alot faster on a higher compression e85 motor. Lucas now has a 690whp FS635 setup on his 11:1 2.0L and it is obvious in the logs that it is at the edge based on noise. When the car goes back to the stock ECU we'll see what it looks like as far as if it was real knock or not (I have much to say on the AEM "knock control but thats another thread). acthink when we get to turbos that are in the 3586 range of airflow, they are so efficient that 29psi on pump with excellent timing isnt hard. I have run mine out to 32psi recently and it really looks like I can keep going if I didnt mind find the mechanical edge of the stock bottom end. I am sure we can run 13:1 on E98 without much of an issue, but what we do in a racecar versus what a "streetcar" is setup with are entirely 2 different things.
I am very much with David when he says that some of the best combos are not ultra high compression or "high compression" motors. Our 9:1 1G Eclipse seems to make alot safer power on the 4202 than the Evo does at only 10:1.
We have also found that the old hotrod rule of 4% per full point on a given setup holds true. The 3065 car mentioned at the outset made 633whp with 11:1 at 32psi versus the 580ish it made the year before at 9:1. There were some other changes made with respects to reciprocating mass that gave is some additional power as well as a cam change that later got us to 640+ before we were once again out of fuel.
I am very much with David when he says that some of the best combos are not ultra high compression or "high compression" motors. Our 9:1 1G Eclipse seems to make alot safer power on the 4202 than the Evo does at only 10:1.
We have also found that the old hotrod rule of 4% per full point on a given setup holds true. The 3065 car mentioned at the outset made 633whp with 11:1 at 32psi versus the 580ish it made the year before at 9:1. There were some other changes made with respects to reciprocating mass that gave is some additional power as well as a cam change that later got us to 640+ before we were once again out of fuel.
Sep 29, 2009, 10:14 PM
#42
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I cannot dedicate myself to E-85. There is absolutely no E-85 easily available where I am at in NC, only 93 and sometimes 100/110.
At the same time I just cracked a piston or a ringland and upgraded to an FP RED.
I am trying to up my compression ratio when I get new pistons to increase my throttle response and N/A torque because driving here in the mountains is proving to be difficult with the loss of torque from the Red.
I'm not sure if I want to go with 9.5:1 or 10:1 but I am definatly doing a standard bore build assuming the cylinder walls are not scored up to much? I am also planning on upgrading the valvetrain and rods so that I can rev it out to around 8,500 because I do road race the car.
I am also looking to make a peak 550whp.
So what are my options realistically? I'm not an engine builder so my knowledge is limited for the time being. What would you guys running high compression recommend I do
At the same time I just cracked a piston or a ringland and upgraded to an FP RED.
I am trying to up my compression ratio when I get new pistons to increase my throttle response and N/A torque because driving here in the mountains is proving to be difficult with the loss of torque from the Red.
I'm not sure if I want to go with 9.5:1 or 10:1 but I am definatly doing a standard bore build assuming the cylinder walls are not scored up to much? I am also planning on upgrading the valvetrain and rods so that I can rev it out to around 8,500 because I do road race the car.
I am also looking to make a peak 550whp.
So what are my options realistically? I'm not an engine builder so my knowledge is limited for the time being. What would you guys running high compression recommend I do
Sep 29, 2009, 10:59 PM
#43
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now i think im going to regret my decisions... im going with 8.3:1 pistons from the older 4g63's. now i kinda wish i would have went with my original plans and do a 10:1 motor. o well we will see what happens. its not a DD so maybe it will be ok?