The E85 switch is one of the best things I have ever done. Even with getting the jetting optimum for mph, both vehicles I did the swap on liked less rpm...200 rpm to be exact. The dyno backed up this stat with both being tried. Can't explain it, but love it...2 more mph, and 200 less rpm!

I shift at 6000 and trap at 6400. hardly spinning this motor'

also i just went to a 12 in rim for my 29.5/10.5W tires and traction at us 41 was not an issue as usual

my CRT trans worked flawless as usual
http://coperacingtrans.com/

and my MendezMotorsports 511 never missed a beat
http://www.mendezmotorsports.com/

http://www.youtube.com/user/BBDUSTEWR#p/a/u/0/MV7_G86EEYk

632 chevy with E85 dominater i converted with QF kit

non HP carb so i had to modify the boosters to fit

used 110 MJ instead of 96 in kit

bleeds in kit would not fit side by side so we machined heads

jet ext were size of a 104 jet so we drilled them out

idle mix screws 3/4 out

started instantly , idles great at 1200 , super responsive , and sounded almost scarey coming off the t-brake.(for a chevy)

and that reg is got to go

Tuning E85 as per Mark Sullens

First of all, you must understand that your NOT tuning a GASOLINE Carburetor, E85 is a different fuel and must be tuned differently than Gasoline.

I’m sure that Phil or someone could chime in with the particulars of E85 vs. Gasoline and the physical differences….

One of the problems with tuning E85 is that you really never know if your lean or fat until you test it with an wideband O2, reading the plugs doesn’t always work because ethanol is a cleaning fuel and your plugs could look new, even after a few months.
Plus the fact that the fuel will change from E85 to E70 as it switches from summer to winter blends.

If you do not have a wideband O2 gauge then water temp has always been a good way to tune your jetting, and I suggest for Racing or street driving that the temperature needs to be at least 170* as the Ethanol requires a temperature of 172* to vaporize.
I dont know why it works, but I have found through my customers feedback that a 7-9* temprature rise in the 1/4 mile will net you the best and most consistant power.

So what about the carb itself:
Several different things control your idle; Idle feed restrictors, idle air bleeds, idle air mix screws and more.

The idle air mix screws in the sides of the metering blocks are used to fine tune the idle by allowing an air/fuel mix to enter the air stream of the venturi below the throttle blades.
While you may hear they need to be 1 ½ turns out, this is not the case, it is just a good starting point in a properly tuned carburetor.

It is important for your throttle blades to be set properly to achieve a good idle and prevent hesitations, usually you will want a small square in the transition slot [ ] as viewed from the bottom of the carburetor, however in some footbrake race applications this is not always the case and a secondary that is slightly more open with the primary slightly more closed will net you a better transition into the 4 barrel side of things.

The main jets controls most cruise & W.O.T. fuel metering.
The main jet under cruise conditions supplies most of the fuel and this circuit is easiest and most commonly tuned.
If @ steady speeds (2200-2800 rpm / return road rpm) the engine surges it is too lean.
You can usually lean the main jets down till you get this surge at 2200-2800 rpm & then richen up the Jets by 2 jets #’s to be safe.

If at this RPM you’re sluggish and lazy, you could be too large on your main jetting.

Winter Blend - The higher gas content in the fuel the lower the jet needs to be (E70),

Summer Blend - The higher Ethanol content the larger the jet needed (E85).

Because of the changing fuel and the weather changes these two should virtually cancel each other out and you should never have to go more than 3-4 sizes in a jet change

Typically on E85 1 jet size change, unlike gas, will make a difference in performance.

again....if you do not have a wideband you can tune your jetting for a water temp change of 170* to 177-179* in a 1/4 mile pass.
more than 9* rise and your lean on your main jetting.
less than 7* rise and your rich on your jetting.

and for the record, when I tuned my jetting with my wideband, my temprature went up 8* in a 1/4 mile pass.

Now its time for Power Valve tuning:
When you accelerate from cruise to W.O.T. manifold vacuum drops to almost 0" and the power valve opens increasing fuel flow to the main well and thus to the boosters.
This additional fuel is needed for high demand situations (full throttle) and the power valve restriction channels are the way to tune it (2 channels that are visible when you remove the power valve).
The Primary Main Jet (PMJ) + the Power Valve Channel Restrictions (PVCR) should always net the same flow as the Secondary Main Jet (some exceptions do apply)
In the carburetors I build I determine what flow I want from the rear of the carburetor then I decide how much fuel I want the PVCR to add, once I know these two a handy chart I have will tell me what PMJ needs to be in the carburetor…this will keep the carburetor balanced front to rear usually within 2% of flow.

So how do you know which Power Valve to use?
First I always suggest a 4-window high flow alcohol power valve, just because I don’t want restrictions in the power valve.
I try to get an idea of how much vacuum you have at idle in gear and I will drop the Power Valve opening rate by 1.5-2” depending on the type driving.
Changing the Power Valve to a higher or lower number to tailor when the added flow through the PVCR starts.
Bigger number will pull fuel sooner and add fuel to the middle of the power curve, while a smaller number could lean the curve…
This is where wideband testing really helps…and Let it be known that my good friend Eric did some testing and not all power valves are created the same.

Just because it says it will open at 6.5 doesn’t mean it will…. Eric can tell that story if he chooses.

What about MAX power and the top end?
People will sometimes tell you to jet for MPH…those people probably never used a wideband.
I found that you can get the fuel curve right through jetting down low then tailor the top end with an adjustable air bleed.
You will find that a small amount of air bleed change (.002) in air bleeds could have a large effect and you may need to go through the previous steps to “super tune” your carburetor again.
The air bleeds will generally effect the upper rpm band of the engine though a slight change can be seen all the way through the fuel curve….

After you have the idle/off idle main jet tuned and the PVCR tuned, then you can adjust the top end fuel curve by changing out the HSAB (inner bleeds on top of the carb)

Smaller air bleed............richer high and mid rpm mixture.
Larger air bleed.............leaner high and mid rpm mixture.
Smaller fuel jet...............leaner low and mid rpm mixture.
Larger fuel jet................richer low and mid rpm mixture

Typically with E85 you will want more fuel under higher cylinder pressures. A fuel curve that gets richer as rpms climb is desired.

Changing the float levels alters the amount of fuel in the bowl (reservoir) and the carburetor’s ability to feed the main wells through the jets. By raising the float level the engine’s response is quickened as you have raised the fuel level inside the main well allowing the fuel to be picked up by the booster quicker.
This is an adjustment frequently used to eradicate a lean stumble but is not always the answer to a lean stumble.
By lowering the float levels, the activation of the main metering circuit is delayed and consequently produces a leaner mixture coming off idle. For street applications the latter condition is more economical.

Off Idle Hesitation: Is one the most common problems w/E85 carbs especially when used on modified engines. If you experience an off idle stumble as soon as you accelerate from part throttle or idle check the Water temp first, cold engine can and will usually have a stumble or hesitation. (remember 170*)

dont forget to check the distributor for correct initial timing ….no seriously, I have had customers call me with issues and it ended up being a distributor issue.
(Inadequate timing will also cause a backfire through the carb under acceleration).

Still have a hesitation? check the pump circuit to make sure that the squirter produces fuel as soon as you move the throttle. If not make sure your linkage is set properly (there should be little (.015) to no play between pump arm and pump linkage at idle), and then if you have no pump shot trace the pump circuit back to locate the problem.
I have had the floating check needle stick closed before…. not a fun task to undo.

If you still have a stumble, as a test adjust the idle mixture screws about 1 turn richer from best idle & see if this cures the problem. If this helps, you can bet the idle circuit is too lean and will need larger IFR or smaller IAB.

One thing to remember when it comes to pump shot is that you only want enough pump shot to cover the lean hole in the fuel delivery curve, any more can make the car lazy.
People tend to get crazy and I have heard of Nozzles as big as .067” with 50cc pumps…crazy, and a cover up to another problem at best!

I hope that I have helped you with some tuning questions, and I ask that if you would like to add to this then feel free to comment.

I have tried to surround myself with a few friends that Know E85 and can share some different perspectives to this wonderful fuel…..

Be safe….go fast!

old mans carb is done

do they sell a conversion kit for the 4150 main body??? if so how much do they run??

They do sell a kit for the 4150 carbs but there is a little more you need to do to make it right than what comes in the kit. The major thing is that if you have gas 160 boosters in the carb you will need to have them swapped out with a set of 170-172 through hole boosters.

I got lucky with my 2 conversions. My one carb was an 825 race demon with interchangable booster. So I simply sent the boosters out and had them drilled to .172, could have done it myself but didnt have the right bit.

My other carb was a BG Speed Demon 850 which had 184 boosters so no change was required.

those tips are from Mark Sullens web site and they seem to have worked in my case but you could be right about them not working in every case.

but out of all my research he seems to be the one E85 guy that seems to be getting it right

but in the end i am listening to the QF guys and so far so good.

i did get my best performance across the board first time out

Yeah, but your saying that your temp raised 10 degree's "ish", and he's saying 7 degree's is rich, 8 degrees is right on, and 9 degree's is lean.

So you mush be lean?

It's just common sense that the head type/design (iron vs. aluminum), radiator size, fan type, shroud design, etc... will all effect the temp change during a run, regardless of jetting...

I read what Mark wrote, and he's probably the master of E85 so it's hard to argue, but I think he's making a general comment, not a biblical tuning reference.

VON said it will get you close if you don't have the proper test equipment.how many people do.

mark sullens says the same thing


it is only some helpful tuning advice that has helped me and apparently VON too.

if you disagree so strongly with his advice by all means feel free to totally diregard it.



this post was simply about letting people know about my E85 results not to start an argument.

That's pretty much my point, who's running digital gauges, that can tell the difference between 7 and 9 degrees (fat/lean). Not many (if any), so how is the common guy supposed to tune with that.

If my motor heats up to 15 degrees during the pass, so I make a jet change so it only heats up 10 degree's but slows down, am I going to change it back? Of course. You're still going to jet with performance, not water temp.

The motor I'm building is going together for E85 (14:1), but it's EFI so it has a wide band...

QWK... did you add any more timing over the gas set up...
I havent yet but was planning on it

My combo may be weird, but I was using 34 degrees with gas and that was real close with E85. I am currently running 32 degrees because when I actually did the back to back timing tests, it was almost no different on the timeslip.

Flat top piston, 0.039" quench, etc. etc.

---

Thanks Jim for the info

I love hearing all these stories about E85 working, and working well, for less money then race gas. Its as much fun as a Mopar beating up on a Chevy.

OK, now lets say for instance, you don't race on a 1/4 mile track. I pull the chain tight and pull a sled for 300' at 6000 rpms.....I suppose to tune correctly I need to get a wideband setup? I put mine together last year and adjusted the idle mixture screws, made sure the carb went WOT and it worked great.........No backfire, no overheating, nice starts, and great power over the pump gas.

Michael