Login    Forum    Search    FAQ

Board index » Racing Forum » Engine & Cylinder Head Tech




Post new topic Reply to topic  [ 18 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: methanol camshaft
 Post Posted: Tue Apr 17, 2007 8:52 pm 
 
do you guys think an engine burning methanol requires a different cam than one on gasoline? and if so, how? the fuels are very different...


Top 
  
 
 Post subject:
 Post Posted: Tue Apr 17, 2007 10:17 pm 
Offline
Site Admin
User avatar

Joined: Tue Apr 18, 2006 7:38 am
Posts: 11446
Location: Coming At Ya!
I don't think fuel type had anything to do with the choice on mine as Rick has never run an alky engine in his life and he chose the cam for my new bullet. The guy that does my machine work was right along with Rick for the most part and he has never run an alky engine either. So if there is a difference, I don't know about it.

I do know that some head porters do some different stuff for alky engines though.

Maybe HighVE, Curtis or some of the others will have some additional info.

_________________
My Garage Is My Domain And My RRE Scrapbook

"Detroit, MI. and Chicago, Ill. are perfect examples of what 50 years of Democrap control does to anything it touches. Any questions?"


Top 
 Profile  
 
 Post subject:
 Post Posted: Tue Apr 17, 2007 10:19 pm 
Offline
Site Admin
User avatar

Joined: Tue Apr 18, 2006 8:28 pm
Posts: 1780
Location: Newport News, VA
Interesting question. Most guys when they decide to run alky do so with an engine they were running with gas. I did the same thing. I have since freshened the engine and kept the same cam. When I choose a cam, one of the first things I decide is where I want to make my power. I would say that with alky you could run a little more cam as alky makes most of it's torque lower in the powerband relative to gas. But alky generally loses it's benefits above around 7000 rpm or so. I think you could make whatever adjustments that might be needed by using the same cam and adjust the cam timing to fine tune the fuel used.

George


Top 
 Profile  
 
 Post subject:
 Post Posted: Wed Apr 18, 2007 12:42 am 
 
alky makes a lot of bottom end so you can back your cam up some we went from 112 to 108 on mine help it down low and i talked to a couple of cam companies and engine builders lift is about the same i was told but they like more duration for a alky motor. well that's what i was told by some good engine Guy's anyway.


Top 
  
 
 Post subject:
 Post Posted: Wed Apr 18, 2007 1:05 am 
Offline
Site Admin
User avatar

Joined: Tue Apr 18, 2006 8:28 pm
Posts: 1780
Location: Newport News, VA
If you want the increased torque that alky provides in the same rpm range that you had with gas then you would need to retard the cam relative to where it was with gas in order to move the torque a little higher in the rpm band. On my first build with my 496 I had the cam advanced 4*. When I freshened it I installed the cam advanced 3*. I haven't had it on a dyno since then so I don't have hard evidence or exact numbers but I could probably retard it another degree or two. I'm 60 footing better than a lot of 540s and run as quick or quicker than a lot of them but they pull better mph than I do. Could be the cubes or it could be the result of having a little too much cam advance.

George


Top 
 Profile  
 
 Post subject:
 Post Posted: Wed Apr 18, 2007 1:50 pm 
 
good stuff guys.

why would methanol possibly like more duration?

George, i agree it tends to make more power down low, and there doesn't seem to be much gained above 7000 rpm.

when you gonna retard that camshaft George?

Ken


Top 
  
 
 Post subject:
 Post Posted: Wed Apr 18, 2007 5:03 pm 
Offline
Site Admin
User avatar

Joined: Tue Apr 18, 2006 8:28 pm
Posts: 1780
Location: Newport News, VA
I'll probably leave the cam where it is. I like the 1.18 60s. =;

As far as the duration goes...that's why I would retard it from where it was running with gas. Retarding a cam has the same effect as having more duration. Advancing the cam has the opposite effect. So it allows you to tune like you have more than one cam without the expense. The more duration you have puts your power higher in the rpm band. If you change to alky and, everything else being the same, you start overpowering your tires or suspension because of the bottom end torque increase you will get from alky, then you can retard the cam and move that torque farther up the band which will take some from the bottom end and give you a little more top end.

So anywho, that's my theory on cams and alky. YMMV =;

George


Top 
 Profile  
 
 Post subject:
 Post Posted: Wed Apr 18, 2007 6:16 pm 
Offline
Site Admin
User avatar

Joined: Tue Apr 18, 2006 8:28 pm
Posts: 1780
Location: Newport News, VA
I think the thing to keep in mind is that were talking different motors when considering Indy cars. I think the rule of thumb for our V-8s is that as you approach 2 hp per cubic inch, gas will make more power. The 7000 rpm thing is not saying that an alky motor won't make power above that, because it will, but that most of the power increase from alky is gone by then. The key word is most. You'll be real close to what the motor makes on gas at that point. So it stands to reason that if your motor is still pulling at 7000 on gas, it will still pull about the same at that rpm on alky. This is all just to say that most of the benefit of running alky comes real early in the power band.

George


Top 
 Profile  
 
 Post subject:
 Post Posted: Wed Apr 18, 2007 6:22 pm 
Offline

Joined: Wed Apr 19, 2006 6:25 am
Posts: 10
N/a methanol (mechanical FI) doesn't fall off at 7000 but just makes lots of power lower. The prob. with it seeming to level off at 6800-7000 is because most pumps begin producing more fuel flow than can be bled off through the single main bypass. At this point a hi-speed can be installed to bleed off the excess and when properly set up it don't stop hauling the mail. Some say it's just like hitting passing gear when the hi-speed bypass dumps fuel. I think if you can feel that big a difference then it is coming in too late. The transition should be basically smooth. Been running the stuff since early 70s and lots of my BBC engines on Hilborn stacks pulled clear through 8500 after hi-speed setup was dialed in.


Top 
 Profile  
 
 Post subject:
 Post Posted: Wed Apr 18, 2007 7:18 pm 
Offline
Moderator
User avatar

Joined: Tue Apr 18, 2006 4:20 pm
Posts: 1458
Location: Missouri
I don't think there would be a difference on the intake side of the cam, but possibly a small difference on the exhaust because of the extra power being made it may need the EVO a little earlier. This is just speculation as I have no alcohol experience, other than drinking a beer now and then.

Rick


Top 
 Profile  
 
 Post subject:
 Post Posted: Wed Apr 18, 2007 10:59 pm 
Offline
Site Admin
User avatar

Joined: Tue Apr 18, 2006 8:28 pm
Posts: 1780
Location: Newport News, VA
dart441 wrote:
N/a methanol (mechanical FI) doesn't fall off at 7000 but just makes lots of power lower. The prob. with it seeming to level off at 6800-7000 is because most pumps begin producing more fuel flow than can be bled off through the single main bypass. At this point a hi-speed can be installed to bleed off the excess and when properly set up it don't stop hauling the mail. Some say it's just like hitting passing gear when the hi-speed bypass dumps fuel. I think if you can feel that big a difference then it is coming in too late. The transition should be basically smooth. Been running the stuff since early 70s and lots of my BBC engines on Hilborn stacks pulled clear through 8500 after hi-speed setup was dialed in.


Never messed with injection of any kind. That's good info to know. One day I'll probably have to give it a try.


Top 
 Profile  
 
 Post subject:
 Post Posted: Wed Apr 18, 2007 11:24 pm 
 
gdmii wrote:
dart441 wrote:
N/a methanol (mechanical FI) doesn't fall off at 7000 but just makes lots of power lower. The prob. with it seeming to level off at 6800-7000 is because most pumps begin producing more fuel flow than can be bled off through the single main bypass. At this point a hi-speed can be installed to bleed off the excess and when properly set up it don't stop hauling the mail. Some say it's just like hitting passing gear when the hi-speed bypass dumps fuel. I think if you can feel that big a difference then it is coming in too late. The transition should be basically smooth. Been running the stuff since early 70s and lots of my BBC engines on Hilborn stacks pulled clear through 8500 after hi-speed setup was dialed in.


Never messed with injection of any kind. That's good info to know. One day I'll probably have to give it a try.

i did i did i love it ran the big bird for years uh ken maybe back sooner than later for me these damn carbs. =;


Top 
  
 
 Post subject:
 Post Posted: Wed Apr 18, 2007 11:26 pm 
Offline
User avatar

Joined: Sun Apr 23, 2006 1:26 am
Posts: 441
Location: MN in BFE
What I have seen is some alky motors like alot of exh lift. You have think about it but you are burning twice as much fuel with alky. We played around with Jeffs 600ci inj. alky pulling motor last year and we took off 1.7 exh rockers, put on 1.8 and gained 65hp at the wheel. Also you kinda do need the high speed air bleeds for high rpm. I see alot of trucks with 650ci turning well over 8000.

_________________
523ci Brodix 1803 Big Dukes. 1108 HP @ 7700rpm cast intake,single 4 on gas. Heads done by CBOGGS/RaceFlowDevelopment

Image


Top 
 Profile  
 
 Post subject:
 Post Posted: Thu Apr 19, 2007 12:19 am 
 
i remember reading somewhere that the increase of methanol over gasoline is 2.22 times. that's a ton more fuel! is this wet flow?

does methanol burn slower than gasoline? assuming proper mixture, whatever that is?

also less lube characteristics, drier?

Ken


Top 
  
 
 Post subject:
 Post Posted: Thu Apr 19, 2007 8:18 am 
Offline
User avatar

Joined: Sun Apr 23, 2006 1:26 am
Posts: 441
Location: MN in BFE
Yes it burns drier we put a bottle top end lube in the barrels. I would think that it burns slower cause of the consumption of the stuff.

_________________
523ci Brodix 1803 Big Dukes. 1108 HP @ 7700rpm cast intake,single 4 on gas. Heads done by CBOGGS/RaceFlowDevelopment

Image


Top 
 Profile  
 
Display posts from previous:  Sort by  
 
Post new topic Reply to topic  [ 18 posts ]  Go to page 1, 2  Next

Board index » Racing Forum » Engine & Cylinder Head Tech


Who is online

Users browsing this forum: No registered users and 1 guest

 
 

 
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
cron