right---push the edge in the lab dyno--not on a street driven car.
OD

 

But the reverse is not necessarily true . Stuff can last on the street quite well but not so well at the track ......

 

ysll talking about my depends undies again!
OD

 

Not gona argue the point. Put it this way, I can bet ANYONE that they couldnt build a turbo kit that would last ME 50 k for an RX8. Enough about turbo kits, this is a SC thread. If you want to talk turbos either go to the turbo thread or IM me about it, enough said.

 

/\ ahem - you brought it up ...

but fair call .

 

dumb question---would ethanol in the gas (10%) change your tuning requirements?
OD

 

From Innovate Motorsports:

"Tuning Tip: Ethanol Content

We've had a few reports where users could not “nail down” their tune on the street with the LM-1. The AFR's would jump about 0.5 AFR across the WOT band even in the same weather conditions in the space of a few days. Instead of holding a tune, the engine seemed to slowly “yodel.”

Naturally the first thing to blame was the LM-1. But it turned out that the users filled up at different gas stations, sometimes filling up on gas that had 10% ethanol mixed in. As expected, when Schnapps is mixed with cars, things get a little complicated.

If ethanol (stoich AFR of 9) is mixed with gasoline (stoich AFR of 14.7) the resulting gas has a lower stoich AFR than 'pure' gasoline. As the fuel injection is tuned to mix a certain amount of fuel for a given amount of air, the resulting mixture would be leaner when using a fuel with lower stoich AFR.

This can be calculated:

sAFR = (%ofAdditive * sAFRadditive + (90-%ofAdditive) * sAFRgas) /100

where:
sAFR is resulting stoich AFR
%ofAdditive is amount in % of mass of additive (ethanol) mixed in
sAFRadditive is stoich AFR of additive (9 for ethanol)
sAFRgas is stoich AFR of base gasoline (14.7)

For a 10% mixture of ethanol to gasoline by mass the resulting stoich AFR is 14.13

So, for an engine that's tuned to certain AFR at a certain load and RPM on straight gas, the resulting (gasoline equivalent) AFR when running the mixture can be calculated as:

new AFR = tuned gas AFR * (gasoline stoich ratio) / blend stoich ratio

An engine tuned to 12.5 gas AFR will run at the equivalent of 13 gas AFR with a 10% ethanol blend. This is what these people were seeing.

Of course, when running in closed loop, the engine will run at 14.13 AFR instead of 14.7. O2 sensors (incl. widebands) don’t measure AFR, but Lambda. Lambda is defined as actual AFR/stoich AFR. It's a ratio. In closed loop part throttle the engine is just running at Lambda 1.0, regardless of fuel. The same would be true for other Lambda values when running closed loop at WOT using a wideband. The engine would run at the tuned Lambda and everything would be fine. Open loop systems would need to be retuned for alcohol blends though."

 

Yeah - What Mars said. It will require a little more fuel, and closed loop fuelling will compensate. The long term trims built by this the closed loop feedback will also help in open loop to some extent.

Cheers,
Hymee.

 

Great info thanks . what if you are getting 0 trims? Something going on?
Moon is helping me but I thought I may as well post in case some others could run into this.
noticed my a/f's on a steady state light load 25-28% cruise at around 3.4-- 3.8 k speed in the 70's, engine temps 170's(. ---you know interstate driving had started going in the low 15's ! 15.1 etc (no w/m on),
I am getting 0 trims per efi dude.
Now give it a very slight load and all is well like up a small hill, very slight increase on the throttle, etc, wot stuff all is well, increase rpms to approx 4k and all is well--lower rpms and it stays the same.
idle is all over the place --from 13.9 to 15.5 flashes but by large, mostly in the 14's
curious as when i replaced my fuel pump with a KNOWN good pump/filter and sock and on cranking for about 10 sec the a/f's were STEADY at 14. 2--no bouncing around at all. then it started the bouncing. it could be so many things.
I am noticing by far more of those small signs on the gas pumps (MAY contain a max of 10% ethanol) and I am thinking that may be causing some of this.
All thoughts appreciated
OD

 

weird --but fixed--just turned my w/m up just a little!
Watch out for that ethanol guys.
OD

 

I'm heading down to Pettit tomorrow and later to Moroso. The weather is going to be perfect (74~54 hi-lo). I'm hoping for at least 5 pases.

 

I think you meant Palm Beach International Raceway (new name for Moroso). Good Luck.

 

have fun in your perfect weather, tomorrows forcast for here is high of 34, although it is good for the 8's lungs...

 

Arnt you comming down here in the next few weeks?? Dig out your shorts!!!

 

I have a feeling I should "search", but I need some quick advice. I haven't started my car in about two weeks (07 auto/pettit sc). Is there a procedure to follow if its been sitting a while? I imagine the rotors are rusting away, with all the oil having dripped into the pan!. Should i start it as usual? or is there a way to get some oil to the e-shaft and seals? Thanks!!

 

yup got my tickets two days ago... I'll be down there wednesday the 28th-1st

 

You shouldnt have any problems, just let it warm up.

 

How many days did you say you were gona be in florida??? Can you make a 2 hour each way trip down here??

 

There is a little thing that id like to say about premixing. In the years that I worked on 2 strokes I learned that the oil in the gas wont seperate from the gas till it gets warm first. In the time it takes to do so it can wash what oil out and cause it to run a little dry on oil at first. Since in a 2 stroke the fuel runs through the crank case first it takes a fully warmed up motor to get the fully lube potential from the premix. The same would apply to premix in a rotory but it has less time to seperate and not wash the oil off of the housing. Its somthing to keep in mind.

 

damn you Juan, Its freezing cold and foggy here. I keep getting wheelspin in 3rd gear unless I'm real careful on the throttle!

 

Juan got a 13.5

 

Launch problems or he is heavy?
He should be low 13's---probably launch.
OD

 

Drag radials would help a stage 2 Pettit car break into the 13s.
(A little bird told me)

 

He had a 2.1 60' when he got that 13.5 (he was launching at under 3500 rpms). He seriously drove like a grandma, and still managed to smoke us. Drag radials would have helped his car break into the 12s.

I ran a 13.8, with a 1.9 60', but I launched at 5700 rpms. I'm going back in the next month or two, and hopefully I'll run in the 12s (I have bag sitting in my trunk that contains an extra 50 whp).

Pictures and videos to come soon.

 

I'd need to find my timeslip, but I'm sure I 2.0'ed my 60' back in 2004. All stock 'cept for me Hymee catback.

Cheers,
Hymee.