High Compression VS Low Compression Opinions

[bison]

HP is a calculated number of RPM and Trq. Great thread.
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Excellent point. Hp should be thrown out the window and replaced with "mass flow" for more accurate comparisons of airflow through engines. About 75lbs/min is what you are seeing here on both logs.


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[bison]

Also most internet descriptions of "how a turbo works" fail to mention it takes work to push the exhaust out of the cylinder and extra work to push it out as the exhaust pressure increases. It's pumping backward against crankshaft rotation absorbing power.


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[forzfed]

In my simple mind:
Work (Trq) is achieved through pressure (force) and leverage (stroke). The key is to control pressures and associated heat energy of combustion.

HP is a calculated number of RPM and Trq. Great thread.

You confused me. I agree with,except for your reference Work(trq)? As far as I know they are not the same W=force x distance, which is what you said. Power = (Force x distance)/time. Brake Power(BP)= Torque x ω(omega), which is what you said. Indicated Power= Pressure(mean) x Area of Piston x length(stroke) x Number of power strokes per second.

 

[bison]

You confused me. I agree with,except for your reference Work(trq)? As far as I know they are not the same W=force x distance, which is what you said. Power = (Force x distance)/time. Brake Power(BP)= Torque x ω(omega), which is what you said. Indicated Power= Pressure(mean) x Area of Piston x length(stroke) x Number of power strokes per second.

He may be referring to the exhaust pressures leverage on the turbine blades


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[Mr.Spool]

Dont fear the boost, don't fear the CR,

 

[Jerryl]

You confused me. I agree with,except for your reference Work(trq)? As far as I know they are not the same W=force x distance, . . . .

Had a weak moment and stand corrected.

 

[Ttype6]

I've always liked these explanations of torque and horsepower.
Torque is a measure of an engine's ability to do work.
Horsepower is a measure of how fast an engine can do the work.

The turbo Buicks out accelerate their competition for the same reason that the 1970 GS Stage 1 out accelerated it's competition. They both have an ability to do a lot of work from very early in the rpm range.

The most important thing you need to move a stationary object is the ability to do work.
Man oh man,do our cute little engines possess the ability to do a lot of work.

 

[Jerryl]

Agree 100%. That was my original intent in my attempt but failed to correctly explain with the laws of physics.

Our cars may not the fastest but have earned and maintain legendary status for being one of the quickest.

 

[Mike T]

Here's a 9.45:1 Iron head engine. Looks like about 1 sec to 15psi. Half throttle foot brake MFS 6766 .85 a/r. His engine makes the same power as the 8.3:1 aluminum headed (higher flowing potential for sure) stock short block engine in the blue car at approximately about 7 psi less manifold pressure. Same turbo on both engines. Cam overlap within 2 degrees of each other at .050". It's not just a little gain in efficiency. It's huge in this example.


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A question just for fun. If both cars were at the track running heads up. Would he put you on the trailer or could you tune around the disadvantage of lower compression?

 

[No disintegrations]

A question just for fun. If both cars were at the track running heads up. Would he put you on the trailer or could you tune around the disadvantage of lower compression?

Trick question! Bison Don't bring it on a trailer! HA HA!

 

[bison]

A question just for fun. If both cars were at the track running heads up. Would he put you on the trailer or could you tune around the disadvantage of lower compression?

He wouldn't put me on the trailer because I never trailered that car anywhere for one. Second I've got several hundred Dyno hits thousands of quick street hits, hundreds of hours of drive time in the street and way more suspension upgrades like better shocks, better rims and tires, car is about 300lbs less race weight, etc. I've already proven what the car can run with way less cool guy stuff and less power. He'd be making a lot more power but be noticeably slower. If we were to do nothing but take his engine and put it in my black car and let it eat it would be very bottom 9's.


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[Mike T]

He wouldn't put me on the trailer because I never trailered that car anywhere for one.

Well aware of that.....It was a figure of speech to bring a lightheartedness (spelling ???) to the question. Whoever rated the question friendly got it exactly as it was intended. The scenario of who would win was more about the engines themselves (high compression vs low compression).

Thanks for your honest reply to the question.

 

[Mike T]

Not many takers on the low compression side.....thought there may be a couple of 3HP per cube (or more) guys out there.

This keeps taking me back to a conversation with Ricardo La Costa 10 plus years ago where he said "They think I'm crazy but I love compression". For those that don't know him he was going 8.30 a long time ago....stage stuff of course.

 

[kandc7]

Yep

Isn't Richie Balcom's engine compression like 8:5:1?

Yep it sure is...

 

[TTipe]

You confused me. I agree with,except for your reference Work(trq)? As far as I know they are not the same W=force x distance, which is what you said. Power = (Force x distance)/time. Brake Power(BP)= Torque x ω(omega), which is what you said. Indicated Power= Pressure(mean) x Area of Piston x length(stroke) x Number of power strokes per second.

Torque=(FD); Torque is the (Combustion Force applied to the Rod Pin) X (the distance from the crank pin centerline to the Rod Pin centerline). Horsepower can be calculated a HP=(TQ X RPM/5252). This equation can only be used if only 1 unknown exists and the solution of either torque / horsepower uses the same rpm.

 

[Mike T]

that's if you can make that kind of boost.on a good motor it can be real hard to make big boost the turbo has to have enough nut.

Open to scrutiny.....

GTQ 70 85 housing
ATR headers
THDP
Self ported heads 200+ CFM
Self ported intake (EGR welded)
Forged bottom end
All studs & center caps
8.0:1 compression
Commetics
210/210 roller (507 lift)
Morel limited travel
PAC 1201
1.55 T&Ds
PTC 9.5 N/L 17 blade
Extreme stage II

 

[bison]

Open to scrutiny.....

GTQ 70 85 housing
ATR headers
THDP
Self ported heads 200+ CFM
Self ported intake (EGR welded)
Forged bottom end
All studs & center caps
8.0:1 compression
Commetics
210/210 roller (507 lift)
Morel limited travel
PAC 1201
1.55 T&Ds
PTC 9.5 N/L 17 blade
Extreme stage II

External gate with good controller would Be my first investment


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[bison]

Not many takers on the low compression side.....thought there may be a couple of 3HP per cube (or more) guys out there.

This keeps taking me back to a conversation with Ricardo La Costa 10 plus years ago where he said "They think I'm crazy but I love compression". For those that don't know him he was going 8.30 a long time ago....stage stuff of course.

Yup. I wouldn't be surprised if a lot of the fastest have CR's around 11:1. I know plenty of the LSX guys are running 11:1 with turbocharged engines.


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[RICHIE HIGH PSI]

Low compression here...
8.5

 

[Mike T]

Low compression here...
8.5

Great to have you chime in Richie! I have heard a lot of second hand information on your car (not CR) and it's truly amazing what you have accomplished.
Most guys in your position treat this stuff like it's "top secret" and I would like to that you for sharing this for the sake of discussion.