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Discussion Starter #1
I dunno.Pump gas build for say a bbc or bbf. My thoughts were stay kinda low 8 to 1 ish. Do you guys think getting 700 hp out of a blown 427 bbc are out of the question ?on 91? What about at altitude(4500 ish). raise your static comp. or lower it? Sorry for being such a post whore up here latley..:)grn
 

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Cantard
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I dunno.Pump gas build for say a bbc or bbf. My thoughts were stay kinda low 8 to 1 ish. Do you guys think getting 700 hp out of a blown 427 bbc are out of the question ?on 91? What about at altitude(4500 ish). raise your static comp. or lower it? Sorry for being such a post whore up here latley..:)grn
No, yes and I dont know.:D
 

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Cantard
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Well I dont like posting on stuff like this because there are way to many variables. I told you a bit in pm,s but here is some more. A good # is 8.5. I was talking to you about x section and low boost #s because intake air temps also are a big factor. You can make 700hp with no trouble I have never dealt with altitude but you know what I made so even if you subtract 100hp you still have a solid 700. It is not how much boost you make it is about how much air you can move into that hole without beating the crap out of it. The more you squeeze it the hotter it gets. Another thing is getting the top ring down low on the piston. Making sure the combustion chambers are smooth. I can go on and on but yes I say you should have no problem. I know that guys are even starting to run higher compresion even up in the 10 to 1 range more like an n/a motor and using low boost just to pick up on the volumetric efficiancy. Like you would on a nos motor.
Paul
 

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Wishin I was at the lake!
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As a point of reference my 568 is 8.2:1 and dyno'd at 1010 (corrected) @6200 at around 10 psi boost, good intercooling, 34 deg timing, and 91 octane. Motor also has full ceramic coatings and piston coolers as well. Didn't push it harder but probably could have. Centrifugal blower so a little more efficient (i.e. less heat) than a roots. EFI and knock sensor in place to pull timing, just in case. Not saying that it's a great combo, but so far it has been very happy for 3 seasons on pump gas. I run it at Powell often, usually try to put some good gas in it to start off with (like 100ll av), then dilute through the weekend with 87. Have run it on straight Dangling Rope 87 without issues, but try to stay out of the throttle as the mixture gets weaker.
 

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Discussion Starter #5
Thanks guys, for the record I wish I would have said 87 octaine. As my machineist says" pinging will ruin your whole day" lol:D
 

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Discussion Starter #7
Thanks all. Brian what does an intercooler for a centrifugal blower look like?? 71 I think you need to give me the # of the guy that ports your heads. :D
 

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Discussion Starter #10
Brian are you sure that didn't come out of an alien space craft?(wow) What's that in it's hard to tell from your avatar. 71 what's your # then, and yes that is cheating.lol
 

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Wishin I was at the lake!
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Brian are you sure that didn't come out of an alien space craft?(wow) What's that in it's hard to tell from your avatar. 71 what's your # then, and yes that is cheating.lol
28 open bow Magic Cat. In other words, lots of hp, not much speed... :|err

The motor is what happens when you let a rookie loose in the machine shop...

:D
 

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"It's HONDO, honey"
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Brian knows his $hit :D a buddy lol. And yes his boat is a space craft, a knock off of the Millinium Falcon brand. :)hand
 

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Discussion Starter #15
O.k. I'm 11.5 to 1 and melted a set of 990's(lack of octain syndrome.lol) at 4250 ft. elev. I must be missing the boat. I have the same bottom end now and alum. heads instead of iron, and I haven't been brave enougph to try to run it on straight pump gas for over 2 years.
 

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Wishin I was at the lake!
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O.k. I'm 11.5 to 1 and melted a set of 990's(lack of octain syndrome.lol) at 4250 ft. elev. I must be missing the boat. I have the same bottom end now and alum. heads instead of iron, and I haven't been brave enougph to try to run it on straight pump gas for over 2 years.
87 or 91? 87 = probable melt down even at your elevation. 91 would be doable if a few other factors were all just right...


Kyle, must have you fooled bud, ha ha! :D
 

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21' Daytona
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I doubt there is an "ideal" comp ratio, as each builder has his preferences. You should be able to achive your desired # with low or high static C/R. If you have an engine builder your comtortable with, use what he suggests, then he'll be in his comfort zone on what to build, and you should end wih with a reliable engine.

P.S. 87 would scare the crap outta me with any kind of forced induction.
 

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Cantard
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I doubt there is an "ideal" comp ratio, as each builder has his preferences. You should be able to achive your desired # with low or high static C/R. If you have an engine builder your comtortable with, use what he suggests, then he'll be in his comfort zone on what to build, and you should end wih with a reliable engine.

P.S. 87 would scare the crap outta me with any kind of forced induction.
You should get your 91 tested= you be scared. lol
 

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Discussion Starter #20 (Edited)
Hey Chris. No the motor was on 91 and red x(b-4 I knew where to get 110) As far as comp. ratio...... I dunno I don't get it .I understand if you do a real low compression motor then it will be real lazy without boost. I just someone could tell me which direction I should go if I'm trying to build a motor for higher altitude. Common sense tells me I would want a slightly higher static ratio than you sea level guys..:D
 
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