[cr55]

Cold Knock hit the nail on the head. Aluminum heads allow an 11 to 1 compression without a lot of trouble, but no higher. The cam duration and overlap are critical to engine life when the number goes up. Watch out!...CR

[carsavvycook]

[QUOTE=ap72]


Lastly cook, I'm not trying to discount what you say or what you know, but knowledge does expire. What you know is worth the most when you learn it, and as time goes by and the world changes so does the value of your knowledge.

QUOTE] That is a false, and very shallow statement. Once again, here you do it again. Everyone retains, and grows more knowledge every day of their life. That knowledge is retained by everybody in their own personal life, or field of work. I agree the knowledge level needs to advance with the times, but the old is not forgotten.

[Cyberats]

This thread is named "compression ratios and pump gas" and not "how to build my 383 racer" but anything that has to do with it is accepted.

However.... I see those of you claiming "higher compression higher octane" as the people who INTERPRET Einstein, interpret technical books to suit their beliefs. There's a Hole in your Mechanical training that you completely covered up and try to excuse it with bad physics. Not one of you were able to explain in details as to why the opposite is true. I asked a simple question about stock cars and daily drivers, not a fuzzy logic built racer. Besides they run aircraft fuel at 12-13:1 to be able to get better performance, acceleration, speed out of them than you would with normal octane, NOT that they would not run on 87.
Back 20 years ago, pump gas was rated as 96/92/86, went down to 93/91-90/87 and then 91/89/87 as new stock vehicles' compression went up from 8:1 to 9:1 to 10+:1. How do you explain that ? Without getting into physics it makes sense higher compression burns lower octane gas at the same mpgs & performance as lower compression burns higher octane gas.

[ap72]

"I agree the knowledge level needs to advance with the times"

That's exactly what I'm saying, knowledge and theories evolve.

[the hack shack]

I built a 388 with 5.7 rods, aluminum pro topline heads 10.7 compression I run 36deg timing ,544 lift cam turn 6500 rpm in my 72 nova I run pump gas 91 or 93 runs great no problems on the street(no detonation) but mix 50/50 when Im not nice to it.

[ap72]

hey hack, you mind giving us the rest of your setup, I think it would be a great affordable example for some guys. Namely, intake, exhaust, trans, stall (if auto), gears, duration on cam, and anything else you may think is critical. Oh, and the temp of T-stat you're running.

[carsavvycook]

Originally Posted by ap72

hey hack, you mind giving us the rest of your setup, I think it would be a great affordable example for some guys. Namely, intake, exhaust, trans, stall (if auto), gears, duration on cam, and anything else you may think is critical. Oh, and the temp of T-stat you're running.

I have to ask. Are you trying to get more information to load into a computer program, or data base?

[glen242]

Originally Posted by ap72

Yea, I have my BS, University of Missouri- Rolla, now called Missouri University of Science and Technology. Its really well known in the Midwest, but not really a big school, around 6,000 students, 80% of them engineering related. And yes, I got my MBA in Environmental and Industrial Management from SEMO (I taught Construction Management), and I will be starting my MS in Civil Engineering at SIUE this January. Hopefully eventually I'll make it back to Rolla for my doctorate, or maybe just settle at Wash U since its in town. I sit for my PE after Dec 2009.

That profile hasn't been updated in a LONG time. I guess I didn't think people actaully read it. And yes I'm 23, that part is current. I no longer cheerlead, may try to get on as an assistant coach though. And I'm curently a project engineer in the St. Louis area.

I'm also a Leo and I enjoy holding hands and long walks along the river.

4-5 year BS Engineering degre, 2 year MBA degree, all by the age of 23. WOW!

[ap72]

Originally Posted by carsavvycook

I have to ask. Are you trying to get more information to load into a computer program, or data base?

No, I was actually getting it to serve as a nuts and bolts running real world example of a high compression streetable engine based on a gen 1 block. I've seen a lot of others, but they are more radical and racey, this one appears to be more street friendly, which I'm sure appeals to a lot of people on here. As far as computer programs go, I have a few but I almost never use them. I just draw up some spread sheets that do most of the calculations. They are good to use, but the programs are not an absolute either.

And thanks Glen, but earning degrees really isn't that hard once you get through your first 3 years of college, then it just becomes routine. I guess that's true with anything though.

[BBCMudbogger]

Lolololololol

[OHD]

I run 11.25:1 on the street with pump gas. Al heads AL BLOCK

[ap72]

Originally Posted by OHD

I run 11.25:1 on the street with pump gas. Al heads AL BLOCK

head and block material make less of a difference than most people think when it comes to on the street detonation prevention. The shape and finish of a chamber and piston crown affect it much more. Other things factor in too, but I believe much to the credit that aluminum heads are given wrongly goes to the material selection when it shoud go the the actual design and dimensions.

[Cyberats]

Does Aluminum engine cast & heads wear out faster if you had a racer engine ?
Anyone considering titanium/steel alloys or even titanium/ceramic/steel ?
Is there anyone building engines from "non-conventional" alloys ?

[the hack shack]

its a 350 4 bolt studded crank & heads,60 over ,zero decked,nodular iron 383 crank,eagle h beam 5.7 rods, ross forged pistons, comp ext energy 507-510@110 deg lob sep hyd cam ,1.6 rockers adds .033 so its 544lift, aluminum top pro line heads stage 3 porting 64 or 67 cc chambers$1800 (cant remember)10.7 comp ratio, victor jr intake, 750 holley double pumper (cant remember exact jetting but the power valve is blocked),msd 6al box,pro billet dist,36deg all by 3200rpm,180 degree thermostat,th350 hughs 3000 stall, dougs full length headers, dual exhaust with h pipe and flowmasters, in a 3000lbs 72 nova ,4.11 geared 12 bolt spooled,28" et drag radial 275/60/15 ,factory rear suspension with slidealink bars runs 117 mph in 1/4 mid 12s (bad et good mph)by gps haven't been to track yet only on street. should be in the neighborhood of 450-475hp by numbers, nos onboard but haven't hit the button yet. I never added up all costs but I know its in the $6500 range. Say does anyone have a desktop dyno program that will run my combo??just curious. next year will run e85.

[OHD]

Originally Posted by Cyberats

Does Aluminum engine cast & heads wear out faster if you had a racer engine ?
Anyone considering titanium/steel alloys or even titanium/ceramic/steel ?
Is there anyone building engines from "non-conventional" alloys ?

No they last same and are repairable, yes there are compacted graphite blocks available. I use titanium rods.