ulakovic22

I've done all the math until I'm blue in the face and I come up with a DCR of around 9.1 to 9.3 (SCR 10.8-11.1) and since I'm having to use a thicker gasket (0.062) since the block had to be milled my quench is now 0.060. I know this obviously isn't the ideal set up, but will I see any considerable negative effects of this on the street? I'm sure the tune is where it's at, but will it be a simple pull of a few degrees timing or more involved than that?

Thanks,
Anthony

Loadre

What size cam are you running? Thats a lot of DCR for a street car (pump gas). You'll probably get lots more answers in Advanced Tech, btw.

1racerdude

If you have figured ALL the variables a 9.1 will do. A .060 quinch is not desireable but runable.You will be surprised at the amount of timing you have to pull to get it out of detonation. The cam plays the biggest part in your DC.
They run their best when the piston just "ticks" the head,but this isn't recommended on a street engine .A .035 quinch is about minimun for a steel rod motor turning 7000 or under.
I am running a 9.4 or close to it on 92 octane but I built the engine expressly to run it that high without detonation.
You would be better off with under 9.0 to cover all situations during the summer heat.
You must have a really small cam to not have any bigger split between static and dynamic. You may have not figure all the variables.

ulakovic22

The cam is 224-236 w/ .56? lift intake and exhaust on 110 LSA. It's not big in my book either, but the IVC at 42 degrees. Inputing the numbers into the calc. on www.kb-silvolite.com gives the numbers 10.8 and 9.1 for compression ratios. Those are with a 0.062 comprssed gasket too. I posted the thread over there so hopefully it will get a couple of more responses.

Thanks,
Anthony

ulakovic22

The info I used was as follows:

Bore: 4.030
Stroke: 3.48
Rods: 6.0
Pistons: -4 cc
Deck Height: 9.008
Heads: 55cc
Gasket Bore: 4.060
Gasket Thickness: 0.062
IVC: 42 (kb said to add 15, so computed number was 57)

Is there anything I missed?

Thanks,
Anthony

1racerdude

Need the advertised duration of your cam and LSA and * of advance or ICL
Will not work without these numbers.

ulakovic22

Don't know advertised, but @ 0.050 is 224-236 on both a 110LSA and 110ICL

Thanks,
Anthony

WS6T3RROR

its impossible to figure dcr with .050 numbers. you need the advertised number which is closer to the point when the intake valve actually closes. which by definition is what dcr is, compression cannot start until the intake valve is closed. and why exactly did you have to use a .060 i know you said they decked the block but dang is the piston out of the hole?

ulakovic22

The piston is in the hole .008 of an inch. I just used the calculator and kept inputing gasket thickness until it came out close to what I would need to run on the street. I then looked around and found a gasket that would fit my needs. I'm just trying to double check my numbers to make sure before putting this thing together.