just a little unclear on tuning

[Mephisto]

since theres really only 91 oct available in CA without buying race gas; knock is pretty much inevitable.

now my question is, since getting 0* of knock on 91, is going to be pretty much impossible, should i be aiming for 0 knock with say 100 oct?

to the best of my knowledge my timing is accurate, ive replaced the plugs, cap, rotor, plug wires, pcv valves, fuel filter, fuel pump, ran injector cleaner, and installed a 160* thermo. i havent filled up my tank with 100 oct, and run DM tests to check knock... but it sure as hell isnt going away with 91.

i just want to get my truck running at its best, before i start using the ultimate. if im getting 8*+ of knock on the stock set up, the ultimate is pretty much useless.

mrweelr i know you did a shit load of work to eliminate knock, whats the lowest amount of knock you got on 91 oct?

 

[Tooky]

Neal, here's what I would do. Ok, on my truck I run 93 octane always (or higher) and I still get the Big Knock. So if you had my truck, the 91 octane would not be the major factor (since it knocks even on 93). I don't know what the fix is for mine yet but I have a ton of ideas, I can email them all to you if you want to browse for some to use on your own.

On the other hand, if you believe it is merely the 91 octane that's holding you back, then the best test would be to try some 93 octane somewhere and see. Is there somewhere you can drive within 1 hour to fill up with 93? Like a relatives house or something you might run past sometime soon? The reason I don't say just go and fill up with 100 is that it's so much higher than 91 that you won't be able to tell if 93 would have been enough. Anyways, let's say 93 gives you 0 knock and 91 gives you 8* knock. IF that is the case and you are sure, know what I would do? I would just retard the timing or lower the boost! What else can ya do? Besides an SMC Alcohol/Water Injection kit ($350).

 

[Mephisto]

josh, thanks for the suggestions, but unfortunately i dont know of any stations that sell 93. so what im thinkin of doing is a 100/91 mix... that should give me about 94 or 95... which i think would be close enough. if it really makes a huge difference, ill start really considering the alky kit.
a few degrees of knock is fine i dont really expect to get 0 knock, and i dont really have the time or the knowledge to mess with it. and im sure as hell not about to pay some asshole who knows just about as much as i do to work on it either. go ahead and send me your list anyway, ill try whatever i can, when i have time. till then ill just continue drivin my sy like a sonoma.

 

[spooldup]

Hey tooky. Whats your list of causes for knock. i need to start looking. What causes it?

 

[CrazyAl82]

TookyCat, you metioned an alcohol injection kit, how much would that raise the octane?

 

[Tooky]

On 2002-03-31 12:40, CrazyAl82 wrote:
TookyCat, you metioned an alcohol injection kit, how much would that raise the octane?

I am pretty sure it's somewhere in the neighborhood of 100-108 octane but I really don't know. I know it is "close" to race gas but not quite as high. However it has a cooling effect too so I don't know if that is enough to bring it up to the same level as race gas , but you would think so. I'm sure each truck is different and you wouldn't find out until you tried your own but this will give you the idea. I don't have alcohol inj. on my truck but I hope to in the next year.

 

[Tooky]

On 2002-03-31 09:40, 92 black typhoon wrote:
Hey tooky. Whats your list of causes for knock. i need to start looking. What causes it?

On the SyTy knock is usually caused by ignition. Making sure your system has the right ignition, fresh within the last 3 months if your knocking now. You also have to make sure it is the right components like the SyTy Readme recommends. Plus you can check datamaster to see if your system voltage is at least 13.0v under WOT, hopefully 13.4v. If not then you can check the battery, grounds, alternator, make sure the alt has the right size pulley (not an underdrive). It could be the ECM too.

Some times it's not the ignition but usually is. Here is a small amount of other things you could check, fuel delivery - is it getting enough fuel under boost (verify with fuel pressure gauge), maybe your fuel pump wiring is rusty or some crap and your pump isn't getting enough voltage and it is not putting out enough pressure under WOT. Or maybe it's dying early or your fuel filter is clogged. You should check your plugs to see if 1 is off and maybe there is something wrong with that cylinder. You can run a bottle of the red 104 Octane Boost and then check the plugs to see which is the most red, and the least red, to see which cylinder is the richest. What about the GM Top Engine Cleaner, you can run that to clean your intake, or you can take the whole intake (IC and all) off and clean it out inside, I have heard of that reducing knock too. Verify the timing make sure it's 0 and verify TDC. Check the vacuum lines make sure there is no leaks, that can cause weird problems. There is some more but that is off the top of my head.

One other thing, if you are really wracking your brain, recheck the ignition THREE times, because it's the SyTy curse.

<font size=-1>[ This Message was edited by: TookyCat on 2002-03-31 13:25 ]</font>

 

[spooldup]

i do have atr under drive pulleys on her. This will cause knock? I also just did some runs with her. I don't get any knock until around 7lbs. The knock is more when i drive it in od. It is less when it's in d. Why?

 

[Tooky]

I don't think the underdrive pulley itself causes knock, but if it causes your system voltage to lower, then that could result in knock because of not being able to produce a good enough spark. What is your voltage at idle and WOT? With my underdrive the voltage has gone as low as 11.2v at idle and usually goes to 12.8v at WOT. I want to get rid of it ASAP.

 

[spooldup]

mine does the same thing tooky. Just ran datamaster on her after you said this. Actually with the lights on, defroster, rear defroster, high beams, and rear wiper i just about killed the truck. I switched stuff off right before it died.

 

[djwaggoner]

Neal, you mentioned you had Datamaster. I have it too, and ran into knock when I went to 3" exhaust & 3" cat. Use DM's histogram function, and increase fuel pressure incrementally 'til knock disappears and your in the "white" all the way up. All the rest of the system has to be up to standard as mentioned above. I'm running 91 octane without ANY knock right up to 20 psi initial and 17 - 18 sustained.
You get more knock in OD because the engine is 'lugging' more. It's normal.
HTH

 

[sy2185]

Neal- use Xylene. I picked up 3 gal at a local paint store for like $7.45/gal. Mixed it with 11 gal. 91 octane and at the 1/8mile with 88F ambiant temp and plenty hotter track temp I peaked KR of .8 at 15.1 lbs boost. 1 ounce Marvel mystery oil per gal. is suggested. Though I don't see over 3.5KR usually, the .8 only showed up in the first a early second gears, the rest was 0. Yesterday ran a personal best of 8.833ET at 75.5mph, cutting a .530RT with a 1.828 60'. Alky kit will be here tuesday, back to the track on Sat. Give it a shot. Good luck.
Jeremy

 

[spooldup]

what is this histogram? I am relativly new to datamster. So should raise my fp more? Its at 50.

 

[Daron]

On 2002-03-31 13:15, TookyCat wrote:

I am pretty sure it's somewhere in the neighborhood of 100-108 octane but I really don't know. I know it is "close" to race gas but not quite as high. However it has a cooling effect too so I don't know if that is enough to bring it up to the same level as race gas , but you would think so.

No, you dont know. Its impossible to estimate octane ratings in a general statement when factoring in alcohol. How much alky you spray, whether you mix water with it, and some other factors go into what level of detonation resistance a given motor will experience with alky injection. Race gas and alky are two different animals. However, both generally have the potential to support more HP than pump gas.
Race gas is much easier to tune for. It is a constant in a long chain of variables. The alky adds another set of variables into the tuning mix (how much, when to turn it on) so it can make tuning a bit more challenging.

Unless you plan on running elevated boost levels, alky may not generate the returns expected.

 

[mrweelr]

Hey Neal, sorry for the late response. I just saw this thread. Anyway, I'm in the same boat as you with only 91 octane crap available where I live. I have done TONS of shit to get rid of the big KR and I'm getting close. Basically, I'm getting under 5 degrees KR on 91 now and I only use Chevron or Shell these days. I did fill up with 100 octane racing fuel at the local Union 76 station in San Jose a while back and it worked well but I will still getting some KR, albeit very little. What I've done lately is just dump Xylene in the tank whenever I go out street racing. My truck runs awesome with that stuff in the tank but it's $35 for a 5-gallon drum so it adds up. I'm getting the SMC alky kit soon but I don't want to use it as a band-aid so I'm holding off until I've exhausted every option. Some things that I'm trying now are replacing the stock early MEMCAL with the updated unit from GM and replacing the original ignition module. I also want to clean the upper IC and clean all of the ground points but I don't know where they're all located. Here's what I've done so far:

RedLine WaterWetter $8
Mobil 1 5W30 synthetic oil $30
Mobil 1 oil filter $10
GM Transmission Filter $28
Mobil 1 synthetic ATF $50
GM Fuel Filter $20
AC Delco coil $30
Vacuum Fitting Kit $20
Redline Injector Cleaner(2) $19
RMI25 Cooling System Treatment $25
GM Top Engine Cleaner $6
Magnetic Engine/Trans Plugs $5
Derale Deep Transmission Pan $72
Kenne Bell Cold Air Kit $179
Kenne Bell Red Hots $50
Kenne Bell FPR @50psi $149
Kenne Bell TC Lock-Up Switch $15
ATR Chrome Diff Cover $40
Bob Berterman IC scoop $86
Powermaster 140Amp Alternator $147
ATR High-Flow Converter $200
ATR SS Exhaust $395
B&M Transmission Cooler $50
NGK UR6 Plugs $19
Borg/Warner Cap and Rotor $20
HotShot starter relay $29
ATR TB Airfoil $36
Walbro 255 Fuel Pump $114
Reroute IC Hoses 3/4" $10
Jabsco IC Pump (Hotwired) $132
Koni Adjustable Shocks $343
PST Front Suspension Kit $219
Kenne Bell 2" Lowering Blocks $30
Optima Battery $118
Hood Latch Guard $10
Engine Tie-Down $50
Disabled EGR $0
LoTek 2-Pod 2 1/16" $50
AutoMeter Boost Gauge $57
AutoMeter Electric FP Gauge $211
New MEMCAL #16164174 $50
New Ignition Module $45
New Oil Pressure Sender $30

The NGK plugs helped with KR a lot as well as the GM TEC. Getting your IC temps down will work wonders too. I will post more here after I get the new chip and ignition module installed and test it with Datamaster. Cleaning the grounds and intake are pretty much my only other options after that. It is possible that my original injectors (52K miles) are not flowing perfectly and causing some cylinders to run lean but I'm skeptical about that. When I do the PTE-52 turbo upgrade I will put the 50# injectors in there and kill two birds with one stone. That's about it for now.

_________________
Jeremy
GMC Syclone #434
Yamaha R1 #1525
http://geocities.com/jdonavich.geo


<font size=-1>[ This Message was edited by: mrweelr on 2002-04-01 15:13 ]</font>

 

[spooldup]

what is this gm tec cleaner? Is that like throttle body cleaner just gm brand?

 

[mrweelr]

No, it removes carbon deposits from the combustion chambers which can induce knock. I tried it and I'm a believer.

 

[spooldup]

so the redline fuel injection cleaner is the same thing as this?

 

[SeattleSy#1255]

not sure about the red line, but you want the "preasurized cleaner"...buy a kit to do it.

 

[mrweelr]

I heard good things about the RedLine injector cleaner so I ran two bottles of it through my system. It's supposed to be very concentrated and effective at removing shit, if any, from your injectors. No, it's not the same as GM TEC - The RedLine is for cleaning fuel injectors and the GM TEC is for cleaning your combustion chambers. I would highly recommend both, especially if you have a "high-miler."