Importracer_001

Whats up, I wanna try some C16 in my turbocharged B16 9:1 compr.
I'v eheard that you can run more ignition timing with C16 than with pumpgas.

Lets say if my total timing on pump gas is 15 degrees when boost 16 psi how much can I advance my timing to keep it safe? maybe 17,5 degrees total timing???

Adi Radoncic

U got sleeves?

Importracer_001

Stock sleeves, wiseco 9:1 pistons stock bore and eagle rods, ARP headstuds

DIRep972

iTrader: (1)

Ignition timing isn't a power adder. Nor is race gas. Unless you are turning up the boost more then you don't need to run race gas.

blundar

Ignition timing is not a power adder, true.

Ignition retard is a power killer.

Especially hearing 16 degrees of timing... wow. I'd be willing to bet that EGTs are a lil on the high side because of the amount of energy leaving out the exhaust valves.

Remember race gas is a different beast than pump gas. It burns significantly slower - you will need more advance across the entire tune to have the same power output figures. Also understand that C16 is pretty ******* resistant to detonation compared to 93.

With 93 Octane and a LS motor, I'll run no ignition retard what so ever (vs. 0psi settings) until 3-5 psi, and then start a step retard. With C16, you could get away with not retarding timing significantly till 8-9 psi or maybe even more. The less you retard timing, the more power you will make. Don't get cocky on your first time with race gas tho.


Modified by blundar at 7:23 AM 12/10/2004

.dave

Why don't you put the car on a dyno and find out?

DIRep972

iTrader: (1)

what exactly are you calling BS on? If his timing is tuned properly now, and hes not detonating, putting in a slower burning gas and adding more ignition timing to compensate is just going to get him back to the same point of maximum brake torque.


Modified by DIRep972 at 11:20 AM 12/9/2004

Mase

Blundar, I call BS on you.


chris is right, actually you will be lucky as hell to even make the same power, I bet you wont make as much power with C16 at say 7 psi as you would w/ 93.

I thought you were smarter than that?

mopar junkie

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blundar &raquo;</TD></TR><TR><TD CLASS="quote">Ignition retard is a power killer.</TD></TR></TABLE>

Huh? Most studies show that you want peak cylinder pressure 16-20 degrees ATDC to have maximum mechanical advantage for turning the crankshaft (best torque). You set the ignition timing to whatever value it needs to be for this to occur which is dependent on many factors including engine design, rpm, fuel used, etc.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
Remember race gas is a different beast than pump gas. It burns significantly slower</TD></TR></TABLE>

Got any data to back that up?

blundar

Direp/Mase: I understand what you are saying 100%. I think you may have misunderstood the thrust of my original statement. Go back and re-read the original post:
"Lets say if my total timing on pump gas is 15 degrees"

ASSuming that the motor is somewhat properly tuned (i.e. the timing could not be advanced significantly further w/o detonation on pump gas), you have to ASSume that 15 degrees BTDC is the best timing you can achieve at 16psi. Don't EVEN tell me that this is close to optimal! I will assert that if the octane requirement causing detonation at 16 degrees was removed, the motor would make more power running more ignition advance. What is a way to do that? Race gas. What is another? Richer AFRs. Either way: more knock resistance.

I don't think it is a fair situation to say that Race gas will hurt your power output when a motor is knock limited on pump gas. If you're in a situation where you can achieve MBT without butting up against the knock threshold, you both are 100% right that there is nothing put penalty to running race gas. In a car that was already at MBT on pump gas, higher octane does nothing.

Mopar Junkie: I'll dig around and see if I can find the burn rate information I had. I beleive it was from a SAE publication, trying to remember exactly. Email me or take it to PM if you're really interested, and I'll dig around. If you want a explanation by inference, take a look at the burn rates of aromatics (benzene, tolulene, etc.) versus the burn rates of saturated hydrocarbons, and then think a lil on the composition of race gasolines versus pump gasolines. Google for "Gasoline FAQ"

Joseph Davis

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blundar &raquo;</TD></TR><TR><TD CLASS="quote">Google for "Gasoline FAQ"</TD></TR></TABLE>

Racegas burn slow, no go bang!

Silly Mopar boys... go find me a forged steel 340 crank.

DIRep972

iTrader: (1)

Blundar, let me see if I am understanding you now. You're thinking he's not able to achieve MBT w/ his current combination; and you're proposing that race gas, because it has more resistance to detonation, will allow him to do that?

blundar

basically, yes. In my experience, the knock point will almost always come before MBT on a boosted honda motor on pump gas. (as evidenced by nearly every motor I've touched making more and more power with more and more advance in boost until they started pinging...) A low compression LS at low boost might be an exception to this rule, but I doubt it.

Try running 28 deg advance at 10psi on a LS on pump gas. Now try it with race gas. In one case, you're almost guaranteed to ping and your power output is a moot point because of detonation. In the other, you at least have a chance of having it work. (Numbers were fabricated, hence choice of words. Not a "real world" example.)

Beyond that, there is power to be scavenged from running higher AFRs that can be done safely with race gas because of its resistance to detonation that is just not possible to do with pump gas. Although the difference between 12.0 and 12.8 AFR is relatively small, the difference between 11.0 and 12.8 is much more noticeable.

I will stick to my basic assertion, which is that in a motor setup where tuning is essentially limited by the knock threshold as opposed to MBT, you will see a gain in power from higher octane fuel if combined with leaner AFRs and more ignition advance.

Mase

running 15 degrees on a say an 84mm 9:1 b16 @ 16 psi is probably not optimal.


but properly tuning it on 93 octane and 116 will yield close to the same results, and the 116 will most likely end up being less with the given setup. now turn the boost up to 20 psi, id put some race gas in, but not 116.

116 is a waste on most cars unless they are boosting 700 +

you will yeild the most power with the least amount of octane that does not detonate

Joseph Davis

I can see where everyone in this thread is coming from, but some of you guys can't see your way past the trees.

Importracer_001 was asking a hypothetical Q.

Blundar took Importracer_001 and you literally, is arguing from the perspective that this "real world" timing map wasn't properly tuned in the first place.

You're just playing the good old fashioned bust some onions game, verbally baiting people out. I strongly suggest you bait someone else - Blundar will make you look stupid.

Mase

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by J. Davis &raquo;</TD></TR><TR><TD CLASS="quote">

You're just playing the good old fashioned bust some onions game, verbally baiting people out. I strongly suggest you bait someone else - Blundar will make you look stupid.

</TD></TR></TABLE>


i hope that statement was directed at me, cuz im gonna laugh at that.

He cant make anyone look stupid if he's wrong about something:

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blundar &raquo;</TD></TR><TR><TD CLASS="quote">Beyond that, there is power to be scavenged from running higher AFRs that can be done safely with race gas because of its resistance to detonation that is just not possible to do with pump gas. Although the difference between 12.0 and 12.8 AFR is relatively small, the difference between 11.0 and 12.8 is much more noticeable.
</TD></TR></TABLE>

yes, race gas is less prone to detonation, however you can not run leaner mixture due to higher octane levels, how many times do i have to say it. if you dont believe me, ask ben strader. what do you think happens when u run leaner?

as far as everything else, if the motor is knock limited, yes, you must use race gas, but bseries are not knock limited at 15 psi. and trust me, ive done testing, ive tried using 118 vs 93, and many other octane combinations at lower level boost pressures and you will not make the same power. i do have a little bit of experience with high hp hondas.

also another common misconception is that the higher the octane the longer the burn, octane rating is only its resistance to detonation. ive seen 114 that will burn longer than c16. it depends on its chemical composition.

DIRep972

iTrader: (1)

I don't know anything about any "onions game" but I know blundar is a smart cat, and I got respect for him. remember, he disagree'd with me. So before I got in a full out arguement, I wanted to fully understand where he was coming from, because I felt that we were on the same page just looking at it from a different point of view. anywho,

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blundar &raquo;</TD></TR><TR><TD CLASS="quote">basically, yes. In my experience, the knock point will almost always come before MBT on a boosted honda motor on pump gas. (as evidenced by nearly every motor I've touched making more and more power with more and more advance in boost until they started pinging...) A low compression LS at low boost might be an exception to this rule, but I doubt it.

Try running 28 deg advance at 10psi on a LS on pump gas. Now try it with race gas. In one case, you're almost guaranteed to ping and your power output is a moot point because of detonation. In the other, you at least have a chance of having it work. (Numbers were fabricated, hence choice of words. Not a "real world" example.)

Beyond that, there is power to be scavenged from running higher AFRs that can be done safely with race gas because of its resistance to detonation that is just not possible to do with pump gas. Although the difference between 12.0 and 12.8 AFR is relatively small, the difference between 11.0 and 12.8 is much more noticeable.

I will stick to my basic assertion, which is that in a motor setup where tuning is essentially limited by the knock threshold as opposed to MBT, you will see a gain in power from higher octane fuel if combined with leaner AFRs and more ignition advance.</TD></TR></TABLE>

I don't really disagree with any of that, the a/f stuff I have a different opinion on but it is a case by case scenario.. Where I was coming from w/ my original response to the post; was that I was thinking the owner of the car had a "properly tuned" pump gas set up, and he wants to try out some race gas. He said he has heard that w/ C16 you can run more timing. My response was meant to illustrate the point that running more timing isn't a benefit in itself, it is just a nessacary part of tuning when changing from pump to race gas. I understand how there can be situation's where you cannot achieve MBT(which is why I made the last response i did) but I did not assume that was the case in the situation of this car. Overall, my perspective was that the owner wanted to add race gas so he could add timing to his set up to make more power.. While I think you took the post differently, thinking that he currently has a combination that is not able to achieve MBT w/ pump so he wants to try race gas. maybe if we had some more facts and info on his set up we could put our heads together and come up w/ some good advise.

Joseph Davis

Chemical composition of fuel, eh? Disparity in latent heat of evaporation among different fuels can change "ideal" AFR from your "glorious" 12:1 when you're thinking in terms of thermal management. Depending on which brew you're running, going "leaner" may be entirely acceptable. Argue with that, Stevie.

But, yeah. Ever play with any 100LL?

PS - DIRep972? I like to bait people, and bust their onions, too.

vaporboy12

cant we all just get along

Joseph Davis

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vaporboy12 &raquo;</TD></TR><TR><TD CLASS="quote">cant we all just get along </TD></TR></TABLE>

We are, now. The rules of this engagement have been set to be quite civil, I think. We just had to poke at each other with sticks a little bit beforehand... some of us aren't as nice about it as others

I respect Mase and DIRep972 a lot, make no mistake... but you never get the finest portion of a man's mind unless you challenge them.

vaporboy12

true that. let the poking countiue

Importracer_001

OK guys there is alot of info here! But very confusing

The problem is I don't know if my ignition timing is optimal right now, I dont have access to a dyno and I dont have a Knocksensor or what ever
All I do have is and Wideband meter and a EGT gauge.Maybe my ignition is way too conservative because when I'm running WOT on pump gas let say at 14 psi my ignition timing is at 17,50 degrees max timing. and on 16 psi it's 15.5 degrees

But I want to try 18-20 psi on race gas to make more power but keep it conservative. No to agressive to blow up my motor.
And in proces to do that I thought about using C16 cause it wont detonate easily.

But keep up the discussion on this race/pump gas thing.

mrx

i want to know too... just to get a feeling.

DIRep972

iTrader: (1)

Ok, since you don't have a dyno or a knock sensor, how did you go about deciding on your current ignition timing #'s? Are u just reading plugs? also what system are you using to tune with? You could definitly add some more boost w/ race gas but you really need some sort of tool to help you determine how much timing it needs to run properly.

Importracer_001

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DIRep972 &raquo;</TD></TR><TR><TD CLASS="quote">Ok, since you don't have a dyno or a knock sensor, how did you go about deciding on your current ignition timing #'s? Are u just reading plugs? also what system are you using to tune with? You could definitly add some more boost w/ race gas but you really need some sort of tool to help you determine how much timing it needs to run properly.</TD></TR></TABLE>

Ok I'm using Crome as management system I'm using now version 0.99 but I'm gonna try 1.00 too. Dont know when but soon.
And for monitoring I'm reading my plugs, got a PLX wideband kit and a EGT guage mounted in the 3rd runner of my exhaust manifold about 2,5" from the head

My ignition map for pumpgas( I guess its like 91 octanes), now can You guys give some advice here.
I'll give you some numbers of my ignition map
This is on the High CAM ignition map.

At first I just did a liniar retard but then I changed it to do a manual step retard , in my current Bin now my max timing occurs around 6,5k RPM
at &lt; 5 psi my max timing is 22.25 degrees, &lt;9.8psi 19.25 degrees, &lt; 14.5 psi 17.50 degrees, &lt;19.3 psi 15.5 degrees

MY A/F is about 11.8-12.2 when I boost 14 psi now and my EGT reads 1400F

Do you think there is more room for improvement but still keeping it safe??

Keep the info coming on the race gas vs pump gas thing.

I'm going to the track tonight to test seom things out.