Ok, I'm just asking, why is that we can boost higher on e85 and less on pump gas?

With higher boost, e85 would put more pressure on the block, so why is it "safer" on e85?

I'm asking coz I might go this route.

 

this helped me

http://www.iwsti.com/forums/3016597-post3.html

 

E85 = higher octane than pump. Just plain old boost alone doesn't make it any more dangerous to the engine. However, when dealing with any fuel, you can only safely run a certain amount of boost / timing before you start causing knock / detonation. That's where the boost level can become dangerous. E85 allows you to run higher boost than pump gas without knock due to its higher octane.

 

Ok, from the link, e85 has cooling properties. Cooler air means denser air means more air per inch/volume means more gas which finally gets to more power.

It still doesn't explain the correlation to more boost equating to higher cylinder pressure. What makes e85 safer. Coz the cooling properties of e85 doesn't negate the fact or lower the cylinder pressure, it actually makes the cylinder pressure higher.

Sorry if I'm being difficult, I'm just trying to understand the concept before I actually do the conversion.

 

Thegame, higher octane does make it more so there's no detonation, or to be more specific, less chance of ignition due to pressure...or more commonly called as detonation.

I'm just trying to understand this so sorry for being difficult.

With higher octane, u can definitely change the timing: either advance or retard the timing. But u can only advance the timing so much and not cause tensile stress to the rods. But that's a different conversation all together. What I'm saying is, for every 1lb of boost, it adds flexural stress to the chamber walls, and tensile stress to the rods. I'm not sure how much stress it adds and that's what I'm ultimately asking.

I know pump gas (referred to as 93, even though I'm using calnevari **** 91) as more prone to detonation than E85 due to octane ratings, hence 93 are tuned lower than E85 and vice versa, E85 r tuned more aggressively at higher boost; all due to pressure ignition. If the air/fuel mixture ignites pre-TDC, it's catastrophic to the engine. We've seen images of these, windowed block and such. But that's only if it ignites pre-TDC.

So, the questions that lingers to me r:
Is the added boost pressure minimal that it doesn't cause tensile/flexural stress?
What is the flexural strength ratings of the 4B11T?
What is the tensile strength ratings of the rods?
R the added boost pressure to the chambers from e85 is negligeble, ie 25lbs for 93 vs. 30lbs for e85?
Is the added boost pressure minimal or detrimental to the engine, as a whole?

As such, tuning is key here, and with great tuning, detonation should be able to be avoided, but since we don't live in a perfect world, detonation is still imminent and could cause catastrophic engine damage...more so on a higher boost e85.

But from what I gather, E85 is safer than 93 solely for the higher octane rating, but the questions still linger.

Edit: I re-read this post. I might be just really tired and it looks like my questions r redundant...but in my head they r different questions altogether.

 

Yes, you are putting more stress on the block (assuming no detonation on either fuel), but like stated above, it's safer because the fuel is igniting at the proper time.

 

Our rods are made so they are more likely to survive a detonation event.

By increasing boost and adding timing, you are more likely to have a detonation event.

When switching to E85, due to the higher stability of the fuel (Octane) you are less likely to have a detonation event.

HOWEVER..... Because it allows you to run higher boost, more timing, more torque, and more power.... There is more of a chance that:

A) You'll blow the rods from normal use
B) If a Detonation Event (Knock) or Bad Gas (BIG Knock) occurs, you'll blow your rods or fry your pistons.

 

With that said, how can we determine if the E85 isn't bad? I mean we just pump the gas from the gas station straight to our tanks. Is there something we can use to see and check if the gas is bad? If the gas is in the tank already it would be too late by the time we find out coz the engine detonated already...literally.

Is there such a thing to check the gas inline to the tank from the nozzle?

 

What you're looking for, then, is an ethanol content analyzer. It determines in real-time the e/g mixture. Zeitronix makes one... http://www.zeitronix.com/Products/ECA/ECA.shtml

If you want to check before you pump, you'd want something like this: http://www.fuel-testers.com/

 

The other thing to keep in mind is that the 4b11 seems to be much more sensitive to tuning than the 4g63. If you decide to go e85, you'll want to have thought through the kinds of driving you'll be doing, what is your tolerance on the tune, and that your tuner is both aware of these and capable of addressing them.

With my e85 tune I specified that I wanted a tune that I could take to the road course and beat on all day long while keeping it safe; I was perfectly fine that there was performance left on the board in order to make this the case. If I were only going to daily drive the car and wouldn't be putting it through the wringer at the track, my tuner would probably have been able to crank a little more performance out of it, but without as much margin for safety. And if I were only interested in the highest possible numbers on the dyno, there's even more margin that can be accommodated...

 

I am contemplating about an E85 conversion, if anything, that's my stage 3, together with a new turbo.

 

As far as I know, our motors are designed to withstand more than stock boost and your occasional knock or else it would just blow in stock form the minute you put the wrong gas in or had a small boost creep. I believe Michael at ETS said that they ran 42psi while "testing" and it held together fine with stock head studs.

For testing e85, you can buy a $15 tester from summit racing. I usually use it when it's switching over to class 1, 2 or 3 throughout the year. If you live in a cold climate in the winter you may benefit from a winter blend tune.

I run e85 on the track (not drag strip track) but I lower the boost to 26psi and I really don't notice the difference in power much (30psi is my street tune) since I'm in high rpms more frequently and the power is right there. The only time I notice the lack of power is driving to and from the track in lower rpms.

 

Thanks for the replies. Helped out a lot!

 

This is a great post. E85 is as was mentioned, higher in octane and gives better cooling in the cylinders. As with any tune, there is a safe limit for a stock engine. This would include ignition timing and how much boost is being used. As long as boost levels are within reason, the E85 will help prevent knock, which is catastrophic to any engine. The key is the maximum boost that can be run on a stock block.

The OP mentioned cylinder pressure. Whether running E85 or gasoline, there comes a point where the added stress on the rods or pistons can cause damage to them. This is why I have my tuner keep things in the safe range. On my Honda Civic Si, which was N/A, I was able to run greater igniton timing and cam angle using E85. This of course improved power. On a turbocharged engine, the results can be spectacular.

 

e-85 will get you more power indeed, but in order to benefit fully from it/ go at higher boost levels, you must build the bottom end. I.e pistons, and rods or risk some serious consequences.