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> cfm?, 74 2.0 8:1
CG-914
post Jul 2 2012, 09:03 AM
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Hi everyone,

I have a 74 2.0 with the euro pistons. (Compression 8:1)
My question what is the cfm on those?
Does anybody maybe has the formula?

Thank you! (IMG:style_emoticons/default/pray.gif)
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TheCabinetmaker
post Jul 2 2012, 09:20 AM
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cubic feet per minute?
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CG-914
post Jul 2 2012, 09:28 AM
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I guess, the english acronyms are new to me (from Germany)..

I have the 9550 raby cam and he is talking about 160 and 180 cfm.
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JFJ914
post Jul 2 2012, 09:37 AM
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QUOTE(CG-914 @ Jul 2 2012, 11:28 AM) *

I guess, the english acronyms are new to me (from Germany)..

I have the 9550 raby cam and he is talking about 160 and 180 cfm.

I believe Jake is referring to the airflow through the heads. I believe the 2.0 head is approx 180 cfm. I don't know what the 1.8 head is, but the 9550 cam is designed to work with the stock fuel injection so I think you'll be ok. Maybe Len Hoffman (HAM Inc)will answer a PM.
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CG-914
post Jul 2 2012, 09:48 AM
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Efective power range on the 9550:
160 cfm heads = 2000 - 4000 rpms
but
180 cfm heads = 2500 - 5500 rpms!!!!

So of course I would like to have the 180 cfm (IMG:style_emoticons/default/biggrin.gif)

But it also stats that the 180 cfm (apparently what I have) is better on an 2.1 engine.
Does 2.1 = 2056 ccm?

And then 5500 would be right at the red area...
What are the steps to raise the red area, and with what results?
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TheCabinetmaker
post Jul 2 2012, 09:59 AM
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OK, 2.1 L is a 2056 (stock stroke and 96 mm pistons). For a max redline of about 6200, Jake recommends the heavy duty valve springs, and of course you will have to set the deck height, and do your valve train geometry.

And Yes, cfm = cubic feet per minute.
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CG-914
post Jul 2 2012, 10:01 AM
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the piston pins are 24mm on my engine?

For 6200 rpms I should get my engine counter balanced?
Can I do that in most machine shops?
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HAM Inc
post Jul 2 2012, 11:01 AM
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A stock 2.0 914 intake port flows around 180cfm @.500" valve lift.

If you really want to wake up that 2056 buy a pair of my RS+ heads.
They flow 180cfm @ .400" valve lift. More area under the curve.
They mate up perfectly to Jake's 9550 cam.

They're available through www.type4store.com were you'll find more details about them.
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CG-914
post Jul 2 2012, 01:37 PM
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96mm bore cylinders and RS+ heads are a dream,
but definitely no option financially as a student! (IMG:style_emoticons/default/dry.gif)
Maybe in a couple of years...

But I will go with the 9550 cam and the Jake Raby valve train setup!
Is my read area still at 6200 then?
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TheCabinetmaker
post Jul 2 2012, 01:59 PM
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Once you purchase the cam and valve train upgrade, Jake will talk to you personally and help you determine the best set up for your application. At that time he will answer all your questions. the 96mm, and the 9550 cam is a very popular setup. I have almost 20,000 on mine now and am still happy with the performance.
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CG-914
post Jul 2 2012, 04:47 PM
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I already bought the cam super set, (have it sitting on the table (IMG:style_emoticons/default/evilgrin.gif) ),
but he did not talk to me.
They only do that, when you purchase a consultation for $799 or close to that...

I just think, that the valve train set up is responsible for a higher rpm and not the bore.
But did you (vsg914) got your engine counter balanced?
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TheCabinetmaker
post Jul 2 2012, 05:50 PM
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I guess he has changed the way he does things. He seems to have a lot of things going on.

I had the rotating assembly all balanced.
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CG-914
post Jul 2 2012, 05:55 PM
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QUOTE(vsg914 @ Jul 2 2012, 07:50 PM) *

I guess he has changed the way he does things. He seems to have a lot of things going on.

I had the rotating assembly all balanced.


Did Jake did that for you or a "normal" machine shop?
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Valy
post Jul 2 2012, 10:10 PM
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The max RPM is mainly dependent on your valve springs and engine balance.
The harder valve springs will ensure that the valve close hast enough at high RPM to prevent "valve floating".
Engine balance will save you from braking something at high RPM due to extensive vibrations.
You power band is highly dependent on the air flow (for a given valve geometry). The air flow is limited by the heads but also by your intake system. Stock FI will not pass much more air then the heads can. If you switch to carbs, you can get more air flow assuming you get some 40 or 44mm double webers or solex.
Since you bought the 9550 I assume you have stock. Your power band will not be supper high but your torque will be at relatively low RPM. You probably don't care much about peak power unless you're racing your car at 5000RPM all day long. For street use, the low band torque will put that smile on your face and smoke the Geo standing next to you at the stop light.

Last I know, the 9550 was delivered with WBX springs that are a bit harder than stock and also a bit cheaper. This should allow you to pull the engine up to about 6000RPM but you're not getting more power by doing so.
Hope it helps.
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