well yeah, I agree with all that, but I just can't feature enough octane there (regardless of how much fuel ya put in) to support cylinder pressures and horsepower one associates with 24 lbs boost? particularly on a non stock car........or are you saying we don't need the octane to support maybe 400 hp? (on my car 24 lbs would be 550+ hp) or what?
009's all done @110% Duty Cycle? (T+ tuning)
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AZGN and everyone:
Correct me if I'm wrong, but don't you only need whatever amount of octane it takes to avoid detonation? ie. If a car will run sufficiently on 93 octane, w/o detonating and showing low numbers on the O2, then you have no reason to run more. By my understanding, any additional octane in excess of the level of "no knock", will only hurt HP and slow you down. It's kind of like the old "Too much of a good thing" theory.
And, this is not a rhetorical question, in that I would like to hear y'all's responses.
I too find it hard to believe about 24psi on pump gas, but I have met others who claim they get away with it too, by using alcohol injection to supplement. It should only be robbing horse power if the car is detonating and therefore pulling out timing and nosing over,,, right?
Thanks,
JT
Correct me if I'm wrong, but don't you only need whatever amount of octane it takes to avoid detonation? ie. If a car will run sufficiently on 93 octane, w/o detonating and showing low numbers on the O2, then you have no reason to run more. By my understanding, any additional octane in excess of the level of "no knock", will only hurt HP and slow you down. It's kind of like the old "Too much of a good thing" theory.
And, this is not a rhetorical question, in that I would like to hear y'all's responses.
I too find it hard to believe about 24psi on pump gas, but I have met others who claim they get away with it too, by using alcohol injection to supplement. It should only be robbing horse power if the car is detonating and therefore pulling out timing and nosing over,,, right?
Thanks,
JT
uh, yeah......but most pump gas will not support 24 lbs of boost in our cars....alky effectively raises the octane to 100 or better because of its cooling properties, so that is no big thing
to run 24 lbs under most circumstances other than those I mentioned would most certainly result in detonation
If Bruce has figured a way around this, I would like to know about it! (and it isn't just tuning...)
"24 lbs of boost in your car is different than 24 lbs of boost in my car" is the other variable, depending on your combination, and this may be the most significant thing.....ie HP generated per lb of boost.....if you only make 245 hp at 24 lbs, then fuel is not a consideration....if you make 600 hp at 24 lbs, 93 octane ain't gonna cut it!
to run 24 lbs under most circumstances other than those I mentioned would most certainly result in detonation
If Bruce has figured a way around this, I would like to know about it! (and it isn't just tuning...)
"24 lbs of boost in your car is different than 24 lbs of boost in my car" is the other variable, depending on your combination, and this may be the most significant thing.....ie HP generated per lb of boost.....if you only make 245 hp at 24 lbs, then fuel is not a consideration....if you make 600 hp at 24 lbs, 93 octane ain't gonna cut it!
Intercooler
New Member
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Reading this post, are we sure Bruce's gauge isn't off 4-5 PSI? 
AZGN and INTERCOOLER:
Thanks for the reply. I really do get alot out of both of y'all's postings on every thread. It is nice to always hear "real life" data and facts to back up the statements, as opposed to just theories and opinions. INTERCOOLER: You crack me up!
Anyway, AZGN, your point makes total sense to me on this subject.
And, if MJRWOOD or BRUCE have figured out to get away with 24psi on a high horsepower car, on pump gas, then I want to be in business with them too, when they sell the recipe. I don't doubt either side here, but I would like to see some real numeric data to support it, per the 24psi theory.
Thanks to all of you! This has been an intriguing thread. I think we're all learning something along the way...
Thanks for the reply. I really do get alot out of both of y'all's postings on every thread. It is nice to always hear "real life" data and facts to back up the statements, as opposed to just theories and opinions. INTERCOOLER: You crack me up!
Anyway, AZGN, your point makes total sense to me on this subject.
And, if MJRWOOD or BRUCE have figured out to get away with 24psi on a high horsepower car, on pump gas, then I want to be in business with them too, when they sell the recipe. I don't doubt either side here, but I would like to see some real numeric data to support it, per the 24psi theory.
Thanks to all of you! This has been an intriguing thread. I think we're all learning something along the way...
550 will take a min of 55s, reguardless of boost, and take LOTS of tuning. Talking real HP.
I said with CORRECT tuning, as my car sits now.
If you trying to make due with too small of injectors, ya you'll have a hellva time, you'll be wasting time and fuel trying to figure out what's wrong, when it's the injectors your fighting.
Well, what is detonation or ping? Its a flame front starting at the wrong time and colliding with the right flame front. The two flame fronts meet and you have "thunder" inside the cylinder. Problem is when the do collide, they create a force at an incorrect time, which is usually destructive. If you know what causes this (aside from octane) you can take measures to prevent the cause. If my suspicions are right, Bruces engine has NO sharp edges in the combustion chamber, the chamber is smooth, but not shiny (just a little "tooth"). The pistons might be coated. There may be work to the chamber to change the swirl of the charge. His plugs are probably indexed. His cal is balls on. He has the *right* amount of fuel being injected, the *right* amount of timing to sustain an RPM level and make the most power available at that level. I read something on another list he's on about something to the effect of modifying parameters to cool the piston domes which cools oil and raised his oil pressure. Heh, changing oil pressure in the chip...imagine that! Stuff like that. Thats "blueprinting". Bruce is from the old school..lets find all the free HP we can. I think I remember him saying he was on a Fiat racing team way back, and we all know how racers like to push the rules to the limits. Since we cant add to the engine setup, lets get all we can out of what we got type stuff. Guys like that do the unbvelieveable. I wish I had the "stuff" to know how to do all that. I dont. I can make a car run really good, but my guess is Bruce can do it much better.
On one hand, we have guys like Bruce, making 450hp with 300hp worth of parts, Then we have the guys who bolt on 600hp worth of parts and make 300hp....who say guys like Bruce are full of crap. Who would you say really knows what theyre doing?
Jim, I certainly wasn't implying anyone was full of crap...just trying to understand what was going on with 93 octane and 24 psi....I believe it would be possible to achieve that setup, but it would not maximize power....that is why I asked about some kind of baseline on HP being generated....if, in fact, he can generate 550 hp on 93 octane in a TR, I wanna buy some stock!
By chance some months back while attending one of the local show and shine shows I met Bruce. He may not be all things to all people but he sure has my attention. Turns out we are neighbors ( 40 minute drive ) and the things he' done still dazzel me. I have been fighting my car for a year and a half bought chips from all the guru's and ended up trading 1 problem for another. Like Turbo Jim said he finds HP in many weird places. After mapping my setup and letting him do his thing I'm 1 of those guys who runs 23lbs. of boost on 94 octane w/o alky. Hope to get some runs in soon and find out just what my bucket of bolts will do. I like one of Bruces sayings" if you don't lie to your ECM your car will go fast." One thing for sure since Bruce has done his thing on my car the pucker factor has risen to the point that this old man almost feels like a kid again. Thanks Bruce:
tminer
Not quite normal
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OK, I am still pretty ignorant about this stuff so I am liable to do that 2+2=5 thing. But as to injectors and detonation, it would seem to me that the more fuel that is injected during the time that the intake valve is open, the more cooling and vaporization effect it would have, and that is what makes alky (really only need water) injection work. If true, then properly sized or even oversized injectors might have a distinct advantage over high duty cycles where the fuel is puddling on the intake floor.
Tom
Tom
In a perfect world you could make all the HP you can at 14.7 to 1.
But, like you noted, you have to supress generating hot spots, which lead to detonation. So you have to run richer then necessary to get the fuel to be a cooling agent.
An intake valve is only open 25% of the time, so at the higher pulse widths the fuel is somewhat hitting the floor.
The trick with Water is that it changes the actual chemical reaction in the chamber, and in doing so helps avoid detonation.
The large injector/ smaller duty cycle allows you to more accurately control the injector so that it can operate as designed.
BEATAV8
The Engine Whisperer
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Well, the sidetrack about Bruce's 24 PSI on 93 octane is pretty interesting. I have no problem with it at all and believe if you spend some time in the right places, like thermal coatings and radiusing sharp edges in the chamber and whatever else you can come up with or find in Heywood's Engine Fundamentals book, that it can be done. I'm an engineer by profession, been to school, and learned all about detonation and air/fuel ratios and ignition timing and all that good stuff. Bruce has provided a valuable data point and shown how beneficial anti-knock treatments can be with a turbocharged application.
For the record.... I'm running 100 octane. Engine is stock. When I do decide to rebuild I will definitely consider some anti-knock treatments.
Anyways....
Last night I spent some more time tuning the car. I shifted my philosophy a little and instead of getting all worried about pushing my 009 injectors past static duty cycle, I said the hell with... let 'em have it and let 'em have it good and see what she'll do.
So I went ahead and adjusted MAF WOT on the T+ from 0% to +4% rich and made a run. The result? Injector duty cycles approaching 114% and an engine that was much happier with O2's in the high 780's. Then went a little further.... Adjusted MAF WOT to +6% rich and made another run. This time injector duty cycle hit almost 120% and O2's remained near 800 for the whole run to 120 MPH.
A little irony: In this case, a blatant lie to my ECM has resulted in going faster
This brings to light something I had not thought too much about previously. Lots of folks here have stated that at 100% your injectors are on "all the time". I don't think so. In fact... I know they are on only for the duration of the pulsewidth. Then, in the interest of preserving the injector drivers and coils, they are shut off and get some time to cool down before the next shot. The injector duty cycle is the ratio of these two times (on time : off time) relative to some max reference time which the factory deemed "100%" for the OE injectors and any given engine speed.
Don't get me wrong... I'm not saying that huge injector on-times are a good thing. Tends to drag out the number of crank degrees during which your injector is still squirting. IMO I still need larger injectors and lower injector duty cycles. At least now I know the fuel system is capable of delivering the needed fuel for my engine
For the record.... I'm running 100 octane. Engine is stock. When I do decide to rebuild I will definitely consider some anti-knock treatments.
Anyways....
Last night I spent some more time tuning the car. I shifted my philosophy a little and instead of getting all worried about pushing my 009 injectors past static duty cycle, I said the hell with... let 'em have it and let 'em have it good and see what she'll do.
So I went ahead and adjusted MAF WOT on the T+ from 0% to +4% rich and made a run. The result? Injector duty cycles approaching 114% and an engine that was much happier with O2's in the high 780's. Then went a little further.... Adjusted MAF WOT to +6% rich and made another run. This time injector duty cycle hit almost 120% and O2's remained near 800 for the whole run to 120 MPH.
A little irony: In this case, a blatant lie to my ECM has resulted in going faster
This brings to light something I had not thought too much about previously. Lots of folks here have stated that at 100% your injectors are on "all the time". I don't think so. In fact... I know they are on only for the duration of the pulsewidth. Then, in the interest of preserving the injector drivers and coils, they are shut off and get some time to cool down before the next shot. The injector duty cycle is the ratio of these two times (on time : off time) relative to some max reference time which the factory deemed "100%" for the OE injectors and any given engine speed.
Don't get me wrong... I'm not saying that huge injector on-times are a good thing. Tends to drag out the number of crank degrees during which your injector is still squirting. IMO I still need larger injectors and lower injector duty cycles. At least now I know the fuel system is capable of delivering the needed fuel for my engine
Injector duty cycle is determined by the full cycle of a four stroke engine, or the time it takes to turn 720 degrees of crank rotation. So if your injector was operating at 114% percent the next open and close event would occur in the next cycle. Therefore it is impossible to get more than 100% duty cycle for 1 cycle of the engine.
BEATAV8
The Engine Whisperer
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Whoops!
I think you are right Nigel. I just calculated 30milisec ontime is 900 crank angle degrees @ 5000 RPM. I was thinking 3 milisec!
sorry, my bad....
I think you are right Nigel. I just calculated 30milisec ontime is 900 crank angle degrees @ 5000 RPM. I was thinking 3 milisec!
sorry, my bad....
I've been thru this before, and was told I was wrong...but...tools like DS, I know theyre SUPPOSED to display accurate PW, but heres my dilemma:
I tune my friends car... 009's, I set constant to 42#, I get say 80% DC. I dont like how it idles, play, come up using a 44# constant (2Eh if I remember right) I add fuel in PE cuz I just told the ECM the injectors were larger and the ECM is pulsing them shorter now....now, my O2's are the same, but DC displays 106%. I didnt really ADD fuel, I CHANGED fuel. Now, how can I have 80something % before, and over 100% after and fueling hasnt changed? Because the PW is calculated by the fueling parameters, NOT the actual time between cycles. Thats the only hypothesis I can come up with. So, with that, you would need to actually measure the TIME to make a rev, then apply the time the injector is commanded open to calc sctual PW. Like I said, I've been told I'm wrong, but cant understand again why, when fuel hasnt actually changed, but PW displays significantly different.
Wait a minute. All the way through you say, "I didn't really ADD fuel, I CHANGED fuel". Well the change you made did in fact add fuel.
You yourself in the first sentance of the second paragraph said: "I add fuel in PE".
Well, I don't know how to tell you this, but it doesn't matter where you add fuel, you're still adding fuel. The change you made was a positive one, therefore additive in nature.
The tiny amount you cut the pulse width by changing the injector constant was miniscule compared to what's done by the changes you made in PE.
Waitasecond....
I didnt ADD fuel. I made the ECM deliver the SAME amount of fuel as I had with another constant. Same injectors, I just told the ECM they were larger than they were, so the ECM shortened PW. Then adding in PE to bring my WOT back where it was BEFORE, resulted in DC over 100%, which is not possible!
Lets say the 42# constant was pulsing 18mS. Now the 44# constant was maybe 17mS. The ECM is pulsing the injecters shorter cuz theyre supposed to be larger... Now bringing the 44# constant to 19 or 20mS resulted in a DC going over 100%, but the end result was the same O2 readings. I forget the exact number, but suffice to say, the end result did NOT change...770-780mV the whole way down the track. But DS shows more DC. Thats simply not possible. The injectors did NOT change. All I did was tell the ECM to pulse a larger injecter for a longer time, but it wasnt really a larger injector, so it really didnt add more PW, it just made it the same PW as it was before I changed the constant.BUT showed a different DC in DS.
You know, as a matter of fact, and I gotta look in the code I have for it (which is arguably accurate anyway) but I dont think there even is a calc for engine degrees. All the ECM knows is once the cam sync is picked up, to start the firing/fueling pulses with each crank signal. I mean, does the ECM know that at X rpm it will take Y time to go Z*? Does it calc Inj DC by this? I mean at a certain RPM, in XYZ mS the crank will have turned a certain amount, and the ECM uses this as its DC? SO its not really scientific is it?
Beat the explanation into my head again please!
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