since im running a rechambered head will it cause detonation? i normally run 87 octane should i start using 92?
head detonation?
- Thread starter 89blaster89
- Start date
yea i know it is better and healthier and i do on occasion but why what is the main reason for it?
Because its an air cooled motor and doesn't have the consistent cooling like a water cooled motor. It has a higher chance of developing hot spots in the cylinder that can pre detonate lower octane fuel.
thanks for the info, ill start running 92 all the time then, what do you think about the head detonation then? even when running 92 octane will my rechambered head cause detonation?
this is the only 1 i got, it wasent cut to the full extent, some meat was left on the bone so when i get porting it can be re-cut again. it made a pretty good difference in torque though i have to say.
FYI there is a gas station near you in Auburn that sells ethanol free race gas in 95, 101, 108 and 118 octane. I usually get fuel there before I head to the dunes. Who cut that head for you?
this is the only 1 i got, it wasent cut to the full extent, some meat was left on the bone so when i get porting it can be re-cut again. it made a pretty good difference in torque though i have to say.
That looks really nice. By looking at the depth of the cut,I would guess it CC's out at 23CC's? Squish band width looks to be about 40% of the bore (like the DT200 head).
This will promote "Top end scream" in the upper part of the power band.
Who did the work?
sweeeeeet, it will be nice for whenever i get porting and it will be nice with my right bend pipe
Here is a link the first thing that came up on Google bc I'm too tired to write anything thoughtful:
Is fuel with an increased level of ethanol a problem for small gas engines?
The best thing is to install the head and do a compression test to see what the number is. Post the numbers too help determine if its going to be safe to run with pump gas. It does look like the mounting area has been shaved down a good bit.
I can tell by looking at it that its around 22cc to 23cc chamber volume. Static compression measured by the gage will only tell you so much. Exhaust port timing (height) will determine what your compression will be. A re-chambered head has to be matched to your porting. If its a very small chamber volume,you will be needing an increase in port timing (exhaust port height).
this is the only 1 i got, it wasent cut to the full extent, some meat was left on the bone so when i get porting it can be re-cut again. it made a pretty good difference in torque though i have to say.
Here's my old "DT200" copy that I step cut to close up the squish clearance. If you exclude the step cut,they look one of the same,if not very,very close.
The paper should read "Squish clearance" is now .035 ,not "squish band" is now .035
Here is a 19cc chambered head that I did thats matched to my porting. Notice the "Wider" squish band?...
you need to check your compression to see where your at. If you get much above 150psi you better start looking for some racing fuel to mix in.
Not correct. I run a re-chambered head (150 psi compression) on "premium pump gas" with ZERO detonation. I have cut many of these heads and tested them all with excellent results. No need for "Race gas" with a properly cut "re-chambered" head that has a squish band and proper squish band clearance. A re-chambered head prevents detonation from happening in the first place if designed and cut properly. You also won't need any +4 timing advace mods either. The head does that for you too.
If you mill,or in other words,remove material from the sealing surface of a STOCK head design for an increase in compression,you WILL,without question, run into detonation ,and will reqire "Race gas". "Race gas" will only be a band aid for this situation,and you still won't reap the power benefits that a re-chambered head offers running on "Premium pump fuel".
No need for $6 a gallon "Race gas".
Alot of people like to brag about how they have to run "Race gas".
I always get a kick out of that when I hear it.
Thats cool,but I'll save my money and get more power with the proper head design.
My quad is running just over 150 psi on pump gas without problems and +4 timing. I'm just saying if hes got too much lets say 170 psi he better find some race gas or it will have a meltdown..
Similar threads
