compression ratios and pump gas??? - Page 5 - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #61 (permalink)  
Old 11-12-2008, 10:30 PM
carsavvycook's Avatar
My 2 cents worth
 
Last photo:
Join Date: Sep 2007
Location: Lakeside, CA
Age: 58
Posts: 2,855
Wiki Edits: 3

Thanks: 2
Thanked 2 Times in 2 Posts
Quote:
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?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #62 (permalink)  
Old 11-12-2008, 11:34 PM
Member
 
Join Date: Nov 2004
Location: PA
Age: 72
Posts: 367
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
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!
Reply With Quote Quick reply to this message
  #63 (permalink)  
Old 11-13-2008, 07:46 AM
How fast is fast enough?
 
Last photo:
Join Date: Jun 2005
Location: St. Louis, MO
Age: 29
Posts: 9,484
Wiki Edits: 0

Thanks: 20
Thanked 388 Times in 364 Posts
Quote:
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.
Reply With Quote Quick reply to this message
  #64 (permalink)  
Old 11-13-2008, 09:21 AM
Member
 
Last photo:
Join Date: Aug 2005
Location: Virginia
Posts: 875
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Lolololololol
Reply With Quote Quick reply to this message
  #65 (permalink)  
Old 11-13-2008, 09:39 AM
OHD's Avatar
OHD OHD is offline
Member
 
Last photo:
Join Date: Sep 2008
Location: outhouse
Posts: 285
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I run 11.25:1 on the street with pump gas. Al heads AL BLOCK
Reply With Quote Quick reply to this message
  #66 (permalink)  
Old 11-13-2008, 09:48 AM
How fast is fast enough?
 
Last photo:
Join Date: Jun 2005
Location: St. Louis, MO
Age: 29
Posts: 9,484
Wiki Edits: 0

Thanks: 20
Thanked 388 Times in 364 Posts
Quote:
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.
Reply With Quote Quick reply to this message
  #67 (permalink)  
Old 11-13-2008, 03:56 PM
Cyberats's Avatar
Hydrogen Burning Engine, YES !
 
Last photo:
Join Date: Nov 2008
Location: California, USA
Age: 46
Posts: 48
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
ALuminum

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 ?
Reply With Quote Quick reply to this message
  #68 (permalink)  
Old 11-13-2008, 04:51 PM
the hack shack's Avatar
nuts
 
Join Date: Nov 2008
Location: Superior,WI
Age: 40
Posts: 5
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
compression ratio

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.

Last edited by the hack shack; 11-13-2008 at 09:49 PM.
Reply With Quote Quick reply to this message
  #69 (permalink)  
Old 11-13-2008, 08:24 PM
OHD's Avatar
OHD OHD is offline
Member
 
Last photo:
Join Date: Sep 2008
Location: outhouse
Posts: 285
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
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.
Reply With Quote Quick reply to this message
  #70 (permalink)  
Old 01-20-2009, 01:06 AM
lust4speed's Avatar
Member
 
Last photo:
Join Date: Oct 2003
Location: Inland Empire, SOCAL
Posts: 424
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Cyberats
...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.
I know better than to jump into this, but what the hey. Octane rating is the fuels resistance to detonation and nothing more. Lower octane fuel burns quicker than high octane fuel. Additives are added to slow the burn rate in higher octane fuels. So actually, 91 octane burns a little lazy compared to 87 octane. 87 will give you more bang for the buck - but it will also start the bang before the compression cycle is ready and sound like shaking a tin coffee can full of ball bearings in a high compression engine. Detonation will destroy bearings, rings, and maybe even hole a piston. None of the results are wanted. Bottom line, a 8.5:1 engine will make more power on 87 octane, and a 10:1 engine will make more power on 91 octane (since 87 would probably lead to its destruction). So lower compression = lower octane, and higher compression = higher octane needed.

It was said above, but to repeat, aluminum heads are good for at least 1 point more of compression, and probably up to 1.5 points due to faster cooling of the combustion chamber which tolerates much higher heat generation. Now add in computerization to monitor knock sensors and reduce timing when needed, and higher compression ratios can be tolerated.

I love my Pontiac engines, but definitely admire the 5.3 "corporate" engines installed in many of the modern pickups. I knew when I got a load of marginal gas because the power decreased noticeably as the computer backed out timing to keep detonation in check. An engine without all this marvel would have hammered its internals.

There's a long grade I had to tow up with the trailer and race car. First truck had a built SBC 400, then another truck with an anemic 350, then a truck with the Vortec 454, and finally a truck with the 5.3. Guess what, my highest MPH towing up the grade was with the new 5.3 engine. Had to keep the RPM's up high, but it easily out pulled the 454 - and gets decent mileage doing it.

So, if you have the engineering capabilities of the big three, feel free to run higher compression. Otherwise maybe a more conservative approach might be called for.

Last edited by lust4speed; 01-20-2009 at 01:12 AM.
Reply With Quote Quick reply to this message
  #71 (permalink)  
Old 01-20-2009, 01:11 AM
techinspector1's Avatar
Senior Curmudgeon
 
Last wiki edit: DynoSim combinations Last photo:
Join Date: Oct 2005
Location: Hemet, California, USA
Age: 72
Posts: 13,325
Wiki Edits: 326

Thanks: 842
Thanked 1,154 Times in 953 Posts
Great post.
Reply With Quote Quick reply to this message
  #72 (permalink)  
Old 01-20-2009, 07:48 PM
Cyberats's Avatar
Hydrogen Burning Engine, YES !
 
Last photo:
Join Date: Nov 2008
Location: California, USA
Age: 46
Posts: 48
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
lust4speed Thanks

Yeah thanks, that explains everything and my missconception that octane meant ability to be burned (higher the better).
Which brings me to ask is why my low comp. engine rattle and gets lower mpg from 87 ? (8.9:1) Or should I use 89oct. as standard ?
Mfg. recommends 87 AND better.
Attached Thumbnails
Click image for larger version

Name:	LeftAngleMerc.jpg
Views:	98
Size:	231.5 KB
ID:	35734  
Reply With Quote Quick reply to this message
  #73 (permalink)  
Old 01-20-2009, 08:32 PM
lust4speed's Avatar
Member
 
Last photo:
Join Date: Oct 2003
Location: Inland Empire, SOCAL
Posts: 424
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Best answer that comes to mind is that your timing might be too far advanced. From there , I'd guess the previous owner drove around town at 30 miles an hour and never got on it hard enough to blow out the carbon buildup. Buildup of carbon deposits make the chamber smaller and raises the compression ratio - and also create hotspots that add to the detonation.

You could drive it like you stoke it, but that would be too much of a good thing too soon. Taking an engine that has been babied for so long and introducing it to full throttle runs will probably knock carbon deposits loose too quickly that could settle between valve and seats, or down on the rings - and probably glaze over and ruin the plugs. Best procedure is to gradually bring it up to a fast freeway speed and hold it there for a few miles.

If you have checked everything out, then throw in the towel and run mid-grade gasoline. I have friends that believe the 89 octane fuel isn't run by enough people and this mix might sit around longer than it should. They run regular on one fill up and premium on the next and never let their tanks go below 1/2 full so the overall mix stays about midway.

By the way, too hot of plugs could push the engine towards detonation so you might also want to check their heat range and see if that is what the manufacturer recommended.
Reply With Quote Quick reply to this message
  #74 (permalink)  
Old 01-21-2009, 12:32 PM
Cyberats's Avatar
Hydrogen Burning Engine, YES !
 
Last photo:
Join Date: Nov 2008
Location: California, USA
Age: 46
Posts: 48
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Timing

Come to think of it...
The smog inspection before last, I think the guy put the timing to dead 0 center. Only in the last months did I become aware that the original timing setting is -13/14 deg. and should stay that way.
Time to find a good mechanic again....
But yeah, thanks again !
Reply With Quote Quick reply to this message
  #75 (permalink)  
Old 01-21-2009, 10:27 PM
carsavvycook's Avatar
My 2 cents worth
 
Last photo:
Join Date: Sep 2007
Location: Lakeside, CA
Age: 58
Posts: 2,855
Wiki Edits: 3

Thanks: 2
Thanked 2 Times in 2 Posts
Quote:
Originally Posted by Cyberats
Come to think of it...
The smog inspection before last, I think the guy put the timing to dead 0 center. Only in the last months did I become aware that the original timing setting is -13/14 deg. and should stay that way.
Time to find a good mechanic again....
But yeah, thanks again !
This almost makes me think your balancer is spun.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Octane Booster Info SLR_65 Engine 46 09-30-2007 10:01 AM
Need help on my engine. evil.350@hotmail.com Hotrodders' Lounge 4 08-18-2007 08:06 PM
Compression question for the Pro engine builders.. Axelrod Engine 14 01-16-2007 11:29 AM
cams, heads, and compression ratios Litdave Engine 3 05-22-2004 08:47 AM
Compression 4x4vandale Engine 5 10-09-2003 12:59 AM


All times are GMT -6. The time now is 02:16 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.