3.9 degrees of KR too much?
06-09-2002, 04:12 PM
#3
TECH Veteran
iTrader: (33)
Join Date: Nov 2001
Location: Port Richey
Posts: 4,266
Likes: 0
Received 0 Likes
on
0 Posts
Re: 3.9 degrees of KR too much? Yes thats way too much. You should really have 0kr if everything is runnng right....especially while using nitrous. Do you get KR while running motor only? What size shot are you running? Have you checked you AF on a dyno with a wideband O2 sensor or atleast with Atap?
06-09-2002, 09:50 PM
#4
Re: 3.9 degrees of KR too much? I figured I would get that answer. I see KR all throughout the rpm's. It drops off a little as the rpm's climb though.
I have 0 KR on the motor.
I was running my 5177 wide open, no jets to see how it ran. At the track I run 100 octane and it's fine but I was on 92 when I tried this.
I haven't been to the dyno yet, hopefully soon.
For now I just use autotap.
I tried adding ALOT of fuel with my MAFT but it still had KR set at 15% rich on partial throttle and 14% rich WOT.
Is there anything I can do to add more fuel with my dry kit without comepletely drowning my motor NA?
I cost to dang much to run 100 octane all the time and I don't want the torque of a wet kit.
Any suggestions?
Thanks.
I have 0 KR on the motor.
I was running my 5177 wide open, no jets to see how it ran. At the track I run 100 octane and it's fine but I was on 92 when I tried this.
I haven't been to the dyno yet, hopefully soon.
For now I just use autotap.
I tried adding ALOT of fuel with my MAFT but it still had KR set at 15% rich on partial throttle and 14% rich WOT.
Is there anything I can do to add more fuel with my dry kit without comepletely drowning my motor NA?
I cost to dang much to run 100 octane all the time and I don't want the torque of a wet kit.
Any suggestions?
Thanks.
06-10-2002, 07:23 AM
#5
TECH Fanatic
iTrader: (2)
Join Date: Nov 2001
Location: Killeen, Texas
Posts: 1,655
Likes: 0
Received 0 Likes
on
0 Posts
Re: 3.9 degrees of KR too much? I got the same problem with mine when I had my 150 wet shot in the car. I had as much as 4degrees.... I put the 100 shot in and have 0... I think I am having fuel problems. I have just installed a FP gauge, so I will be able to see if it is taking a huge dip or not.... Let me know what you find out....
Trending Topics
06-21-2002, 07:44 PM
#9
Re: 3.9 degrees of KR too much? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Slart:
<strong>You removed the jets entirely from your kit? ROFL</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yep, I sure did. Thanks for the ROFL <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" />
<strong>You removed the jets entirely from your kit? ROFL</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yep, I sure did. Thanks for the ROFL <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" />
06-21-2002, 11:21 PM
#10
TECH Veteran
iTrader: (33)
Join Date: Nov 2001
Location: Port Richey
Posts: 4,266
Likes: 0
Received 0 Likes
on
0 Posts
Re: 3.9 degrees of KR too much? Lets keep the discusion on a technical level please.
Buy removing the pills from the 5177 kit your only going to get a max flow of around 140 shot. Maybe a bit more with bottle pressure jacked up. Adding more fuel is not the answer. There are 3 things you can do to correct this.
1) reduce nitrous
2) use higher octane fuel (you did that with good results)
3) reduce timing
Your walking a fine line right now. Your KR is a definate indication of detonation. Not good at high HP levels.
Buy removing the pills from the 5177 kit your only going to get a max flow of around 140 shot. Maybe a bit more with bottle pressure jacked up. Adding more fuel is not the answer. There are 3 things you can do to correct this.
1) reduce nitrous
2) use higher octane fuel (you did that with good results)
3) reduce timing
Your walking a fine line right now. Your KR is a definate indication of detonation. Not good at high HP levels.
06-22-2002, 04:50 AM
#11
On The Tree
Join Date: Jun 2002
Location: Sacramento
Posts: 196
Likes: 0
Received 0 Likes
on
0 Posts
Re: 3.9 degrees of KR too much? Sorry, I just thought it was sorta funny. Pulling the jet out of the kit is akin to pulling the thermostat to help overheating <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Anyhow, if you want technical, the problem you're seeing is too much cylinder pressure at low RPM.
Since nitrous flows the same regardless of RPM, it generates torque (cylinder pressure) in inverse proportion to RPM. That's why it gets better as you wind it up. That's also why higher octane stops the detonation.
KR is a very bad thing. It indicates that you're having detonation and the computer is trying it's best to keep you from destroying it. If you'd tried this on a car without a knock sensor you'd have blown a head gasket by now.
The proper fix is to go to a wet kit with a dedicated fuel pump. More fuel will solve the problem. Dry kits are inherently less safe.
A simplier solution is to fake the IAT out in order to cause the computer to drop some timing. If you put a 1000 ohm resistor in paralell with the IAT (that is, short across the leads) it will make the computer think it's getting ~150F air and it will pull 3 degrees of timing.
Of course you dont want the 3 degrees removed when NA, so you should put this on a relay, triggered by the +12 to the nitrous solenoid.
A progressive nitrous controller would eliminate your problem altogether at this HP level.
- Steve
Anyhow, if you want technical, the problem you're seeing is too much cylinder pressure at low RPM.
Since nitrous flows the same regardless of RPM, it generates torque (cylinder pressure) in inverse proportion to RPM. That's why it gets better as you wind it up. That's also why higher octane stops the detonation.
KR is a very bad thing. It indicates that you're having detonation and the computer is trying it's best to keep you from destroying it. If you'd tried this on a car without a knock sensor you'd have blown a head gasket by now.
The proper fix is to go to a wet kit with a dedicated fuel pump. More fuel will solve the problem. Dry kits are inherently less safe.
A simplier solution is to fake the IAT out in order to cause the computer to drop some timing. If you put a 1000 ohm resistor in paralell with the IAT (that is, short across the leads) it will make the computer think it's getting ~150F air and it will pull 3 degrees of timing.
Of course you dont want the 3 degrees removed when NA, so you should put this on a relay, triggered by the +12 to the nitrous solenoid.
A progressive nitrous controller would eliminate your problem altogether at this HP level.
- Steve
06-22-2002, 04:29 PM
#12
On The Tree
Join Date: Jun 2002
Location: Sacramento
Posts: 196
Likes: 0
Received 0 Likes
on
0 Posts
Re: 3.9 degrees of KR too much? > How would I go about the 1000 ohm resistor deal? I have heard of people doing this but I have no idea how.
The more I think about it, get a 931 ohm, 1% tolerance resistor if you can find one.
Get a copy of the wiring diagram and look at the IAT sensor. The IAT sensor is a variable resistance between two wires in the harness.
So putting a 950 ohm resistor between those two wires (which is putting it in parallel) would ensure that the effective resistance of the sensor could not be more than 950 ohms.
950 ohms is what the sensor reads at 122F if I recall correctly (and less = hotter). When the computer sees 122F@100 KPA (which is 14.7 PSIa, meaning no vacuum, meaning WOT) it retards 3 degrees.
So to summarize, assuming the air temp was cold to begin with (and it is when you're squeezing), putting that resistor in place will cost you 3 degrees which will delay peak combustion until the piston has moved down some, and accordingly drop your peak cylinder pressure which will help with the detonation.
If it was only getting 3.9 degrees of retard, I would venture to guess that the 3 degrees of retard you can get through faking out the IAT will be enough to fix it.
Putting the resistor in all the time will cost you those 3 degrees on the motor too, so if you want best NA performance as well you'll need to put it on a relay. Just go to a stereo shop and say you want them to wire you up a relay, triggered off your +12 to your solneoids, that puts a 1000 ohm resistance in parallel with the IAT sensor. They'll probably charge you $50 or so.
The wet kit really is a better way to go technically because with the dry kit you rely on the computer to see that the system is running lean and then compensate, which is not as good as putting in the correct amount of fuel in the first place.
Among LS1 people wet kits have a reputation for hitting harder. That's hilarious because they inject the same amount of nitrous, so any lack of performance when they are first activated is a result of being lean, which is very bad.
Anyhow, I've babbled enough.
- Steve
The more I think about it, get a 931 ohm, 1% tolerance resistor if you can find one.
Get a copy of the wiring diagram and look at the IAT sensor. The IAT sensor is a variable resistance between two wires in the harness.
So putting a 950 ohm resistor between those two wires (which is putting it in parallel) would ensure that the effective resistance of the sensor could not be more than 950 ohms.
950 ohms is what the sensor reads at 122F if I recall correctly (and less = hotter). When the computer sees 122F@100 KPA (which is 14.7 PSIa, meaning no vacuum, meaning WOT) it retards 3 degrees.
So to summarize, assuming the air temp was cold to begin with (and it is when you're squeezing), putting that resistor in place will cost you 3 degrees which will delay peak combustion until the piston has moved down some, and accordingly drop your peak cylinder pressure which will help with the detonation.
If it was only getting 3.9 degrees of retard, I would venture to guess that the 3 degrees of retard you can get through faking out the IAT will be enough to fix it.
Putting the resistor in all the time will cost you those 3 degrees on the motor too, so if you want best NA performance as well you'll need to put it on a relay. Just go to a stereo shop and say you want them to wire you up a relay, triggered off your +12 to your solneoids, that puts a 1000 ohm resistance in parallel with the IAT sensor. They'll probably charge you $50 or so.
The wet kit really is a better way to go technically because with the dry kit you rely on the computer to see that the system is running lean and then compensate, which is not as good as putting in the correct amount of fuel in the first place.
Among LS1 people wet kits have a reputation for hitting harder. That's hilarious because they inject the same amount of nitrous, so any lack of performance when they are first activated is a result of being lean, which is very bad.
Anyhow, I've babbled enough.
- Steve
06-23-2002, 12:10 AM
#13
Re: 3.9 degrees of KR too much? How would I go about the 1000 ohm resistor deal? I have heard of people doing this but I have no idea how.
I am definately thinking about buying a wet kit now, which I should have done in the first place.
Thanks again for the help everyone.
I am definately thinking about buying a wet kit now, which I should have done in the first place.
Thanks again for the help everyone.
06-24-2002, 04:42 PM
#14
Staging Lane
Join Date: Feb 2002
Location: Athens, Ga
Posts: 97
Likes: 0
Received 0 Likes
on
0 Posts
Re: 3.9 degrees of KR too much? Jeffrey, i have a bunch of resistors in the basement if you want one, give me a call sometime i am sure that i have one in that range with 1%. let me know later--DJ
<small>[ June 24, 2002, 04:43 PM: Message edited by: DJ ]</small>
<small>[ June 24, 2002, 04:43 PM: Message edited by: DJ ]</small>
06-28-2002, 05:04 PM
#15
Re: 3.9 degrees of KR too much? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by JimTA:
<strong>Those powershot noids can't flow more than 125 hp, jets or no jets.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thats not true sir. The restriction of the noid it'sself will set an LS1 at roughly a 170-180 shot. Depending on mods and the car of course. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
- Matt
<strong>Those powershot noids can't flow more than 125 hp, jets or no jets.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thats not true sir. The restriction of the noid it'sself will set an LS1 at roughly a 170-180 shot. Depending on mods and the car of course. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
- Matt
