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383 11-22-2007 01:02 PM

Compression on street tunnel ram
 
Hi,can anyone tell me the highest compression for 102 octane fuel. Could 12.5 with a big cam do it or not?
The edelbrock street tunnel ram,does it need a high compression?

chrismac 11-22-2007 06:45 PM

F-Bird is right. A huge cam with a lot of compression isn't really any fun just to run pump gas. I just went through the same crap with a small block 350 bored .030 and domes. I ran a huge cam and it was lazy until 4,000 rpm. I just stepped down from a camshaft that is 310/320 In/ex. duration advertised and 262/270 in./ex. @.050 To a comp cams 294s grind number 12-224-4 in hopes for more bottom end and streetability. There isn't a need of high compression for a tunnel ram because the create a lot of velocity going down the intake runners which helps the engine rev quickly.

383 11-22-2007 11:40 PM

So the street ram don't need the compression the high rpm rams do.
You reckon 600cfm carbs would be a overkill. At just over 7000rpm
would it still be?
The car is a strip car and would not see road time,if it does ones a month.

383 11-23-2007 06:55 AM

On the street ram ,if a cam gets used that makes peak power above 7000rpm,
would it still make good power there? Edelbrock said its for under 7500rpm motors.
I would like to make 1.4-1.5hp per cubic inch.(383)
Can it be done with this setup? I need to choose the rotating assemblies compression and cam.

woodz428 11-23-2007 07:37 AM

Quote:

Originally Posted by 383
On the street ram ,if a cam gets used that makes peak power above 7000rpm,
would it still make good power there? Edelbrock said its for under 7500rpm motors.
I would like to make 1.4-1.5hp per cubic inch.(383)
Can it be done with this setup? I need to choose the rotating assemblies compression and cam.

It appears to me you are building an engine from the manifold down. That is kind of backwards to the way that I think it should be done. Depending on those components that you have yet to choose, it shouldn't be hard to get the 1.5hp per cube....with just a 4 barrel.

1930u 11-23-2007 08:41 PM

Quote:

Originally Posted by 383
Hi,can anyone tell me the highest compression for 102 octane fuel. Could 12.5 with a big cam do it or not?
The edelbrock street tunnel ram,does it need a high compression?

The isky Z-60 grind cam is old school but it works great with a tunnel ram and 10.5 compression. I used it in a .060 over 327 with 4-speed and a 4:56 gear.

Here's the cam specs. High performance. Street/strip. Lopey idle. 3200 Stall. 4:56-4:88 axle ratio. Up to 800 CFM Carb. 10.5-11:1 compr. RPM-Range (3500-7500) Valve Lift (.548 .548) Valve Lash hot (.016 .016) ADV Duration (292 292) .050 Duration (259 259) LC 108...The motor flat out beat the ground (sounded to nice) and it wasn't to bad driveability wise either. Probably wouldn't be as much fun with an automatic.

chrismac 11-23-2007 08:58 PM

If you are building a track ride you need a real bottom end to handle 7500 rpm all the time. Get loose clearances on the mains and rods, Tight clearances on the pistons, lots of camshaft and heads to match. When all said and done you will have a radical 383 12:1 compression or higher and 2gs in the heads and valvetrain just to make the motor last for the long run. 1.5 hp per c.i. is great but its gonna take more than just an intake.

383 11-25-2007 01:27 AM

Thanks for all your input on my questions.
I think 11.5 is what i will use.
Thanks for a great forum.


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