02's are around 785 and kr @ 3.7 degrees at 24# boost. Fuel pressure at 41 lbs with line off. Tryed it at 39-40 but got WAY to much kr. Pump speed at max and turn on point at 11#boost on smc kit. I'm running 94 Sunoco. Question is should I be overly concerned with this much kr on the top of 3rd?? Seems to be the best I can tune so far with the new Scanmaster. Gonna try to lower the turn-on point a couple lbs. I'm running 50-50 mix denatured and H20. Would running straight alky help surpress kr???? Ran straight alky before getting Scanmaster and it ran RICH on OTC 4000!!! Thanks.................................KB
02's and knock
- Thread starter hot6-231
- Start date
- Joined
- Aug 20, 2001
What chip are you running? I have had more sucess running 21++ psi with a RA108 chip since this chip has more "fuel enrichment" after 3000 rpm. On the RA93 chip, my limit is around 19-20 psi, with pump speed @ 10 and the and the turn on point @10-12 psi. Any knock in the top of third is not a good thing, since this is when the car is under the most "load". If i get any knock with alky it is 1-2 kr in the first two frames after WOT and then it disappears on the scanmaster. It may even be false knock, still trying to confirm that though. I run str8 denatured alky. The car is a little rich on the bottom end, but perfect on the top end.(780-800 o2's)
BLACK6PACK
1 sec reaction King
- Joined
- May 24, 2001
I'd be worried about 24lbs of boost and 3.7* of knock. You don't want to do that too many times. Turn up the fuel pressure another pound or two and see if that takes care of it.
Several of the gurus say that they try to run right at 800 MV O2s with the alky. When I was running strait denatured, 800 was too rich. Once I got it down to around 770 the egts fell right in line, so you'll have to figure out what your car likes.
As BSB said, the race chips have better fuel curves for running high boost. It's best to get a chip burnt for alky. They basically take a race chip and turn down the timing a little, but keep the fuel curves as is.
Several of the gurus say that they try to run right at 800 MV O2s with the alky. When I was running strait denatured, 800 was too rich. Once I got it down to around 770 the egts fell right in line, so you'll have to figure out what your car likes.
As BSB said, the race chips have better fuel curves for running high boost. It's best to get a chip burnt for alky. They basically take a race chip and turn down the timing a little, but keep the fuel curves as is.
S
Steve Hill
Guest
you should be concerned about any knock other than transitional knock. By the time you're into third you should have stabilized all flow parameters, and any additional knock is indicating a borderline condition.
You have options. My first and best suggestion is to run 50-50 water/alcohol, if you're not already.
Second best remedy is to use better atomizing nozzles. These do make a difference.
From there you'll either have to increase your w-a flow, or decrease boost.
You have options. My first and best suggestion is to run 50-50 water/alcohol, if you're not already.
Second best remedy is to use better atomizing nozzles. These do make a difference.
From there you'll either have to increase your w-a flow, or decrease boost.
BSB....Chip is a JC 93 "street". B6P.......gonna try bumping the fp up 1-2lbs and re-test. Steve.........already running 50-50 per your suggestion at DD at J&M. It helped GREATLY!! Gonna try different nozzles if bumping fp fails to get me where I need to be. I got a feeling it's just gonna bump up the 02's a little to much. Will find out Saturday and post results here. KB
S
Steve Hill
Guest
hot6- yeah, I remember you now. That was a fun day.
I've discovered most knock and/or tuning problems (at least on my engine) can be traced to one of these:
not enough fluid volume (flow), insufficient atomization, and, to a lesser degree, running pure alcohol.
Here is some theorizing.....
Your turbo, at 24-25lbs, puts out quite a bit of hot air (relatively speaking), similar to a stocker. Your stock IC is being heat soaked on a long WOT pull. You need to get a handle on that heat.
How to do that? Well, you could spend a grand on a huge front mount... OR.. just make your water/alcohol system more effective via bettter flow control.
Look at my first w/a system as an example. This is assuming stock turbo, stock IC, 25lbs boost, high timing, 93 octane:
With a single #24 oil burner nozzle it was difficult to control knock. Dividing that flow volume between two, smaller # oil burner nozzles allowed each nozzle better atomization. No knock. Making that system a two stage (one nozzle on at low boost, the other at a higher boost) helped manage all that flow for better driveability.
Now fast forward a few years to my current system. It is based upon 5 Aquamist nozzles, flowing a total flow of 1 fl. oz/sec (.5 gal/min). This is a lot of flow but is divided between 5 high performance nozzles. Without really good atomization this much liquid would drown the engine. Yet this is what is required to support 28lbs boost (even 30!) into fourth gear without knock.
One last item to mention is the pump. You should check it for output pressure. Higher pressure is better, but at least ~70lbs while spraying through the nozzles. For comparison my pump runs about 110 while spraying, 160 deadhead.
Anyway, this is just my experience with building my particular system over the years and hopefully some of this is applicable to your setup.
I've discovered most knock and/or tuning problems (at least on my engine) can be traced to one of these:
not enough fluid volume (flow), insufficient atomization, and, to a lesser degree, running pure alcohol.
Here is some theorizing.....
Your turbo, at 24-25lbs, puts out quite a bit of hot air (relatively speaking), similar to a stocker. Your stock IC is being heat soaked on a long WOT pull. You need to get a handle on that heat.
How to do that? Well, you could spend a grand on a huge front mount... OR.. just make your water/alcohol system more effective via bettter flow control.
Look at my first w/a system as an example. This is assuming stock turbo, stock IC, 25lbs boost, high timing, 93 octane:
With a single #24 oil burner nozzle it was difficult to control knock. Dividing that flow volume between two, smaller # oil burner nozzles allowed each nozzle better atomization. No knock. Making that system a two stage (one nozzle on at low boost, the other at a higher boost) helped manage all that flow for better driveability.
Now fast forward a few years to my current system. It is based upon 5 Aquamist nozzles, flowing a total flow of 1 fl. oz/sec (.5 gal/min). This is a lot of flow but is divided between 5 high performance nozzles. Without really good atomization this much liquid would drown the engine. Yet this is what is required to support 28lbs boost (even 30!) into fourth gear without knock.
One last item to mention is the pump. You should check it for output pressure. Higher pressure is better, but at least ~70lbs while spraying through the nozzles. For comparison my pump runs about 110 while spraying, 160 deadhead.
Anyway, this is just my experience with building my particular system over the years and hopefully some of this is applicable to your setup.
K
ksteinbach
Guest
Why do you consider running straight alcohol a contributor to knock vs. a 50:50 mix? In my car (a Supra) I can run a much greater volume of pure alcohol than I can water/alcohol solution before I start getting misfire.
K
ksteinbach
Guest
Steve,
You can ignore my previous post. I see there is a whole debate going on later in this forum. BTW, I think the reason my Supra has more power injecting straight alcohol vs. water/alcohol is because I have a fuel controller and have been able to replace some of my 91 octane gas with alcohol so I am using it as a supplementary fuel. BTW, you Buick guys are way ahead of the Supra crowd on this injection stuff, whether water or alcohol.
You can ignore my previous post. I see there is a whole debate going on later in this forum. BTW, I think the reason my Supra has more power injecting straight alcohol vs. water/alcohol is because I have a fuel controller and have been able to replace some of my 91 octane gas with alcohol so I am using it as a supplementary fuel. BTW, you Buick guys are way ahead of the Supra crowd on this injection stuff, whether water or alcohol.
S
Steve Hill
Guest
ksteinbach...
it's not that pure alky won't work for this. Many people are using pure alcohol with good results.
The problem, as I see it, is the alcohol can add considerable BTU's to an engines normal fueling, thus altering the a/f ratio. If this is ignored or not taken into consideration then you will never achieve optimal performance.
Also, the #1 reason I use water-alcohol injection is for control of detonation. The decades of research documentation I used for reference all agreed upon a 50/50 mix for use in this context. I wouldn't want to ignore or second-guess that.
it's not that pure alky won't work for this. Many people are using pure alcohol with good results.
The problem, as I see it, is the alcohol can add considerable BTU's to an engines normal fueling, thus altering the a/f ratio. If this is ignored or not taken into consideration then you will never achieve optimal performance.
Also, the #1 reason I use water-alcohol injection is for control of detonation. The decades of research documentation I used for reference all agreed upon a 50/50 mix for use in this context. I wouldn't want to ignore or second-guess that.
Tried bumping the fp 1 than 2 lbs but now the 02's are in the 820-830 range. Still got 2.2* kr in third. I think i'm going to go with "two" Aquamist nozzle's. Not sure on the size though.........will have to do some research or can anyone tell me what's a good size???? Steve, got any suggestions????Thanks.
Ken B.
Ken B.
S
Steve Hill
Guest
ken, the amount of flow you'll need directly relates to the heat from boost.
I've found you can push these little stock blocks pretty hard; 25lbs is, for me, on the moderate side. If you wanna run that then you'll need around .7-.8 fl.oz/sec. 50-50.
Since the Aquamist nozzles max out at 1.0 mm, you need multiple nozzles to achieve that rate.
I'll suggest you start with three 1.0 mm, but I really think you'd be better off using four .8 mm or .9 mm.
Caution: You must take into account that more injected fluid will fatten up your fuel,and this is what you want as you raise boost. Use an egt meter to fine tune. If you're too lean you either add a splash more alcohol or up your fuel pressure or lower your boost.
If you run a thumbwheel such as Yakmans ME just dial up or down as necessary. slick. And use that egt!
OK, once again, when running in the higher boost range you want to become aware of the differences is air density.
I.E., for a typical 75 degree day you might have a certain fuel pressure and water-alcohol mix and you are happy with 1600's egt. A couple months later its a nice cool day...you are going to be lean unless you add some fuel somewhere, or back down boost. On a cold day, watch out! your boost will be higher making you even leaner. knock knock boom
While I was testing the various combinations I discovered a small trick: if you think you have too much flow, and don't want to pony-up for smaller nozzles all around, just disconnect the line going to any one nozzle (aquamist only). You won't lose any significant boost through the open nozzle aperature because it's just too small. This allowed me to test various combinations quickly and easily. Have fun
I've found you can push these little stock blocks pretty hard; 25lbs is, for me, on the moderate side. If you wanna run that then you'll need around .7-.8 fl.oz/sec. 50-50.
Since the Aquamist nozzles max out at 1.0 mm, you need multiple nozzles to achieve that rate.
I'll suggest you start with three 1.0 mm, but I really think you'd be better off using four .8 mm or .9 mm.
Caution: You must take into account that more injected fluid will fatten up your fuel,and this is what you want as you raise boost. Use an egt meter to fine tune. If you're too lean you either add a splash more alcohol or up your fuel pressure or lower your boost.
If you run a thumbwheel such as Yakmans ME just dial up or down as necessary. slick. And use that egt!
OK, once again, when running in the higher boost range you want to become aware of the differences is air density.
I.E., for a typical 75 degree day you might have a certain fuel pressure and water-alcohol mix and you are happy with 1600's egt. A couple months later its a nice cool day...you are going to be lean unless you add some fuel somewhere, or back down boost. On a cold day, watch out! your boost will be higher making you even leaner. knock knock boom
While I was testing the various combinations I discovered a small trick: if you think you have too much flow, and don't want to pony-up for smaller nozzles all around, just disconnect the line going to any one nozzle (aquamist only). You won't lose any significant boost through the open nozzle aperature because it's just too small. This allowed me to test various combinations quickly and easily. Have fun
Turbo__Tim
One heck of a Tim!
- Joined
- May 25, 2001
Hey Steve, What are your 0-2 readings like at the end of the run?
From your experience, can we rely on them to show richness, or lean condition when spraying?
Egt's are 1600 for my set-up. 1650* is where I pick up knock. I realize egt numbers will vary from one car to another....
Thanks !
From your experience, can we rely on them to show richness, or lean condition when spraying?
Egt's are 1600 for my set-up. 1650* is where I pick up knock. I realize egt numbers will vary from one car to another....
Thanks !
S
Steve Hill
Guest
Tim,
Honestly I have never taken time to correlate them exactly, but, my O2's do readout ~820-850 when egts are low, and, usually .785-.760 when the egts are where I want them. So I guess you actually could use O2's for crude guesstimating.
The egt's are much more accurate.
I strive for temps anywhere in the 1600's, but usually I'm happy with ~1650. Anything under 1600 and my engine gets 'sleepy'. At 1450 it's a D O G.
The engine runs best at higher egts, but must realize they all run best just before melting down <g>
As a (bad) example: Very early am, on one really cold day, me and Brian Lee were blasting up to a car show in Maine, munching a few mustangs and everything else along the way.
I wasn't thinking and had the fueling set for what would be a much warmer day. Right now, however, it was like 45 degrees.
The knock detector went off somewhere up in fourth gear. I was at 26.5 lbs boost and the egt's showed 1760! Holy Molee and double-damn. Added about 5% gas and, voila', egt's came down.
And btw, here's a plug for John Spina's audible knock detector. It totally ignores the quick knock spike I get at wot transition, yet howls like a banshee upon knock _counts_. When knock counts start to increment I know something is going on.
happy motoring to all.
Honestly I have never taken time to correlate them exactly, but, my O2's do readout ~820-850 when egts are low, and, usually .785-.760 when the egts are where I want them. So I guess you actually could use O2's for crude guesstimating.
The egt's are much more accurate.
I strive for temps anywhere in the 1600's, but usually I'm happy with ~1650. Anything under 1600 and my engine gets 'sleepy'. At 1450 it's a D O G.
The engine runs best at higher egts, but must realize they all run best just before melting down <g>
As a (bad) example: Very early am, on one really cold day, me and Brian Lee were blasting up to a car show in Maine, munching a few mustangs and everything else along the way.
I wasn't thinking and had the fueling set for what would be a much warmer day. Right now, however, it was like 45 degrees.
The knock detector went off somewhere up in fourth gear. I was at 26.5 lbs boost and the egt's showed 1760! Holy Molee and double-damn. Added about 5% gas and, voila', egt's came down.
And btw, here's a plug for John Spina's audible knock detector. It totally ignores the quick knock spike I get at wot transition, yet howls like a banshee upon knock _counts_. When knock counts start to increment I know something is going on.
happy motoring to all.
