Engine/Compression Help
Thread Starter
Instructor
Joined: Apr 2005
Posts: 136
Likes: 41
From: Arvada CO
Yes, based on the cam it makes sense. That cam is for sea level performance not 6000+ feet.
Also the heads have 200 cc runners on the intake. This slows the velocity of the intake charge, thereby not filling the cylinder very well until the velocity increases as RPMs increase. Problem is by the time the velocity and RPMs get high enough you are probably running into not filling the cylinder completely due to the lower duration of the cam @ .050.
He is telling the truth. Timing can absolutely be tied to the gearing. Then the necessary retarding of the timing further reduces the engines performance.
Seems like this engine was built for a car with 3.55 or 3.73 gears. Yours has a 3.08. In addition it's probably a 3.08 with a TH350 or TH400 transmission.
This is it's like trying to start out on a 10 speed bike in 5th gear. It will take lots of low end torque to do get moving quickly.
That engine is not going to make lots of low end torque.
The builder provided you with a "one size fits all" engine.
Unfortunately it doesn't work that way.
You, being the novice, did not know that.
He, being the builder, should know that.
Not all builders, or maybe "assemblers" know the difference and the effects of gearing and altitude on an engine performance and how that should be applied to the specific car and it's use.
Is the torque converter still stock?
Changing the gearing to suit the engine is less than ideal and more expense, but it is an option. It will also raise your cruise RPMs, which may or may not bother you.
At your altitude you would probably need something like a 4.11 rear end to get decent performance from that engine.
Check out this page to see how rear end ratio will effect your RPM at various speeds. Assuming 27" tire diameter and you final drive in the transmission is always 1:1.
http://wallaceracing.com/gear-speed.php
Also the heads have 200 cc runners on the intake. This slows the velocity of the intake charge, thereby not filling the cylinder very well until the velocity increases as RPMs increase. Problem is by the time the velocity and RPMs get high enough you are probably running into not filling the cylinder completely due to the lower duration of the cam @ .050.
He is telling the truth. Timing can absolutely be tied to the gearing. Then the necessary retarding of the timing further reduces the engines performance.
Seems like this engine was built for a car with 3.55 or 3.73 gears. Yours has a 3.08. In addition it's probably a 3.08 with a TH350 or TH400 transmission.
This is it's like trying to start out on a 10 speed bike in 5th gear. It will take lots of low end torque to do get moving quickly.
That engine is not going to make lots of low end torque.
The builder provided you with a "one size fits all" engine.
Unfortunately it doesn't work that way.
You, being the novice, did not know that.
He, being the builder, should know that.
Not all builders, or maybe "assemblers" know the difference and the effects of gearing and altitude on an engine performance and how that should be applied to the specific car and it's use.
Is the torque converter still stock?
Changing the gearing to suit the engine is less than ideal and more expense, but it is an option. It will also raise your cruise RPMs, which may or may not bother you.
At your altitude you would probably need something like a 4.11 rear end to get decent performance from that engine.
Check out this page to see how rear end ratio will effect your RPM at various speeds. Assuming 27" tire diameter and you final drive in the transmission is always 1:1.
http://wallaceracing.com/gear-speed.php
Yes, it has a stockish torque converter. I did that because I was told the motor was going to have lots of low end torque and a higher stall was not needed.
I am still concerned about the build, but everyone involved is more focused now and I do believe everyone wants to make this right.
I am going to start another thread and see how people in high altitudes are getting the best performance.
Thanks again everyone for the help. I really appreciate it!
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,170
From: Hermosa
Reelav8r, thank you for all of the advice and data. they have decided to build me another engine! They are as concerned about the detonation as I am and have decided it better to build a new one. I am happy and give credit for standing behind their products. I am sending all the specs of the car to them so they have a record of it and can build accordingly. Yes, they had it before, it was in the form of conversations.
Yes, it has a stockish torque converter. I did that because I was told the motor was going to have lots of low end torque and a higher stall was not needed.
I am still concerned about the build, but everyone involved is more focused now and I do believe everyone wants to make this right.
I am going to start another thread and see how people in high altitudes are getting the best performance.
Thanks again everyone for the help. I really appreciate it!
Yes, it has a stockish torque converter. I did that because I was told the motor was going to have lots of low end torque and a higher stall was not needed.
I am still concerned about the build, but everyone involved is more focused now and I do believe everyone wants to make this right.
I am going to start another thread and see how people in high altitudes are getting the best performance.
Thanks again everyone for the help. I really appreciate it!
