Tuning JECS 720cc injectors and more - Page 4

daemon · 02-16-2006, 05:16 PM

I bought mine from MZM Performance a while back. You might also want to check out the Nissan parts suppliers. The Nismo 740cc injectors are the same thing I believe.

**WolfPlayer** · 02-16-2006, 05:23 PM

Quote:

Originally Posted by STirish

Where did you guys source your JECS injectors? Tim, I believe you found you injectors used?

Thx,
Rob

Yup. I got mine used.

t

STirish · 02-16-2006, 10:02 PM

Quote:

Originally Posted by daemon

I bought mine from MZM Performance a while back. You might also want to check out the Nissan parts suppliers. The Nismo 740cc injectors are the same thing I believe.

They are, I'm just hoping that I can find the connectors without buying an entire harness.

daemon · 02-17-2006, 05:26 AM

Connectors came with the ones I got from MZM. I don't if MZM added them, or if the connectors came with injectors from the factory.

04stiguy · 02-17-2006, 08:10 AM

Connectors

http://www.splparts.com/Parts/Silvia...el/default.asp

daemon · 02-17-2006, 08:32 AM

Great link. Wish I had known the Nismos were the same when I bought mine. Could have saved a few bucks.

STirish · 02-17-2006, 10:26 PM

Quote:

Originally Posted by 04stiguy

Connectors

http://www.splparts.com/Parts/Silvia...el/default.asp

Yes sir, that is where I purchased my injectors from, thank you. Unfortunatly there is a 2 week lead time

Oh well I have the 860cc injectors to play with.

STirish · 02-18-2006, 10:41 PM

The 860's went in today and are coming out tomorrow. Whoa, the 860cc injectors are a little to large for a stock heads/cams/displacement. Keep in mind that I'm at 4200 feet, the 860s may idle ok at sea level with a raised idle. The pulse widths are on the ragged edge even with a raised idle. Can't wait to get the 720s in the car. We'll see if we can get rid of the faint RPM oscillation

I may put the 860s back in when I go with CNC ported heads and C*** cams to see if I can get them to idle at that point

**WolfPlayer** · 02-19-2006, 05:42 AM

Quote:

Originally Posted by STirish

Can't wait to get the 720s in the car. We'll see if we can get rid of the faint RPM oscillation

I may put the 860s back in when I go with CNC ported heads and C*** cams to see if I can get them to idle at that point

Couple things here ...

1) I have noticed that my RPM oscillation can be noticed more during hot weather. Idle RPM was the same so I'm not 100% sure why the hotter weather made the oscillation more noticeable. One guess would be that the hotter inlet temps necessitate less fuel. I need to get logs of the idle RPM oscillation when it is not noticeable vs. when it is really noticeable.

2) Cams DECREASE the volumetric efficiency at idle .... thus, you need even less fuel at idle. This is why most people raise the idle when installing cams ... because the motor is just TOO inefficient due to the decreased Volumetric Efficiency (because of the increase in overlap).

3) Went on a 300 mile trip yesterday with the wife and kids. Car drove completely stock.

t

Christian. · 02-19-2006, 08:36 AM

Quote:

Originally Posted by WolfPlayer

Couple things here ...
1) I have noticed that my RPM oscillation can be noticed more during hot weather. Idle RPM was the same so I'm not 100% sure why the hotter weather made the oscillation more noticeable. One guess would be that the hotter inlet temps necessitate less fuel. I need to get logs of the idle RPM oscillation when it is not noticeable vs. when it is really noticeable.t

We completed some testing with the Helix 860s yesterday and that brings up a question concerning this oscilation you guys are witnessing. What is your IPW at idle with these fuel injectors, warm and cold conditions?

Christian.

daemon · 02-19-2006, 11:31 AM

At idle, warm or cold (as cold as a cold start can get here in Floriday), it looks like I'm stuck at 1.54. Does this make sense? Were you expecting this or something else?

**WolfPlayer** · 02-19-2006, 11:54 AM

Holy reproduction Batman

Mine is 1.54 also in both of the logs that I have reviewed (car fully warmed up such that the idle has dropped down to a warm idle). However, these logs were not taken when the RPM oscillation was that noticeable for me. I need to wait for a warmer day. It just chilled down into the 20's today ......... Brrrrrrrrrrr. And we are suppose to do motor mounts on my buddy's car tonight.

t

daemon · 02-19-2006, 02:12 PM

A few more scatter plots showing that my fuel problem didn't go away, even though the trim plots "got better" with the restrictor in. Guess it really was just because it was harder for me to stay in closed loop in order to really see what was happening via the trims.

This plot shows that the car still has a tendency to lean out around 2800. In fact, it shows that it generally wants to be 1 full AFR point leaner than the corresponding target in the primary fuel map table.

Edit: For the following graphs, the Y axis is the difference between the measured AFR (via LM-1) and the corresponding target given in the primary fuel map (looked up via the load/RPM logged). So 0 (zero) means the AFR is exactly what the primary fuel tables asks for. So +1 would be one point leaner, and, -1 would mean 1 AFR point richer than requested.

So, for fun, I modified the intake calibration and told the car the more air was getting in in the 2v-3v area. That produced this chart. Notice the definite improvement.

Another interesting fact to note is the general tendency for the (eyeballed) linear regression to slowly work towards the rich side as RPM increases. Of course, the 2800 RPM lean bump is even more significant when you take that into accound.

Question: Does this give a clue as to what is wrong? Does this happen on anyone else's STi? Was fudging the intake calibration the right/wrong/indifferent way to handle it?

Related question: Is the general tendency towards rich as RPM increases related in any way to the scale/latencies I picked and should I change them to try and fix that? If so, which way (e.g. latencies up/scale down, or vice versa)? Or, should I just tweak the intake calibration to try and straighten it just like I did to get rid of that bump?

daemon · 02-19-2006, 02:16 PM

BTW, this is how I picked the 2v-3v area to play with on the intake calibration. I really need to tweak it a little better, but the quick expirement showed that it seemed to have the desired effect.

Before...

After...

**WolfPlayer** · 02-19-2006, 04:41 PM

daemon,

Nice. I think that you just need to keep track of the change you made in case you need to undo it later. However, I like the change you made. The car asked for something ... and you gave it what it needed. For now, this modification is working for you. Keep an eye on that area at WOT.

I still need to grab some high quality logs for you to see if my car is doing the same. Drop me a PM when you get a chance to specifically tell me what you did while driving so that I can attempt to duplicate your logging method as closely as possible.

t

02-16-2006, 05:16 PM	#46
daemon The Next Petter Solberg Car: 2004 STi Location: Florida Posts: 887 IWSTI Addict since: Feb 2004 Trader Rating: (0)	I bought mine from MZM Performance a while back. You might also want to check out the Nissan parts suppliers. The Nismo 740cc injectors are the same thing I believe. This ad is not endorsed by this member. Please register or login to hide this ad.

02-18-2006, 10:41 PM	#53
STirish Spec C Club Car: '99 M3/'03 WRX Avant Fav Mod: Modification is wrong! Location: SLC, UT Posts: 1,026 IWSTI Addict since: Sep 2004 Trader Rating: (6)	The 860's went in today and are coming out tomorrow. Whoa, the 860cc injectors are a little to large for a stock heads/cams/displacement. Keep in mind that I'm at 4200 feet, the 860s may idle ok at sea level with a raised idle. The pulse widths are on the ragged edge even with a raised idle. Can't wait to get the 720s in the car. We'll see if we can get rid of the faint RPM oscillation I may put the 860s back in when I go with CNC ported heads and C*** cams to see if I can get them to idle at that point Last edited by STirish; 02-18-2006 at 10:46 PM.

02-19-2006, 02:12 PM	#58
daemon The Next Petter Solberg Car: 2004 STi Location: Florida Posts: 887 IWSTI Addict since: Feb 2004 Trader Rating: (0)	A few more scatter plots showing that my fuel problem didn't go away, even though the trim plots "got better" with the restrictor in. Guess it really was just because it was harder for me to stay in closed loop in order to really see what was happening via the trims. This plot shows that the car still has a tendency to lean out around 2800. In fact, it shows that it generally wants to be 1 full AFR point leaner than the corresponding target in the primary fuel map table. Edit: For the following graphs, the Y axis is the difference between the measured AFR (via LM-1) and the corresponding target given in the primary fuel map (looked up via the load/RPM logged). So 0 (zero) means the AFR is exactly what the primary fuel tables asks for. So +1 would be one point leaner, and, -1 would mean 1 AFR point richer than requested. So, for fun, I modified the intake calibration and told the car the more air was getting in in the 2v-3v area. That produced this chart. Notice the definite improvement. Another interesting fact to note is the general tendency for the (eyeballed) linear regression to slowly work towards the rich side as RPM increases. Of course, the 2800 RPM lean bump is even more significant when you take that into accound. Question: Does this give a clue as to what is wrong? Does this happen on anyone else's STi? Was fudging the intake calibration the right/wrong/indifferent way to handle it? Related question: Is the general tendency towards rich as RPM increases related in any way to the scale/latencies I picked and should I change them to try and fix that? If so, which way (e.g. latencies up/scale down, or vice versa)? Or, should I just tweak the intake calibration to try and straighten it just like I did to get rid of that bump? Last edited by daemon; 02-19-2006 at 02:23 PM.

02-19-2006, 04:41 PM	#60
WolfPlayer Moderator & ECU Tech Car: 05 CGM STI Fav Mod: mo boostaz Location: Fredneck, MD Posts: 3,730 IWSTI Addict since: Jun 2004 Trader Rating: (6)	daemon, Nice. I think that you just need to keep track of the change you made in case you need to undo it later. However, I like the change you made. The car asked for something ... and you gave it what it needed. For now, this modification is working for you. Keep an eye on that area at WOT. I still need to grab some high quality logs for you to see if my car is doing the same. Drop me a PM when you get a chance to specifically tell me what you did while driving so that I can attempt to duplicate your logging method as closely as possible. t This ad is not endorsed by this member. Please register or login to hide this ad.

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02-17-2006, 05:26 AM	#49
daemon The Next Petter Solberg Car: 2004 STi Location: Florida Posts: 887 IWSTI Addict since: Feb 2004 Trader Rating: (0)	Connectors came with the ones I got from MZM. I don't if MZM added them, or if the connectors came with injectors from the factory.

02-17-2006, 08:10 AM	#50
04stiguy Senior STI Driver Car: '05 STi Fav Mod: Cusco Zero 2R's Posts: 336 IWSTI Addict since: Jun 2004 Trader Rating: (0)	Connectors http://www.splparts.com/Parts/Silvia...el/default.asp

02-17-2006, 08:32 AM	#51
daemon The Next Petter Solberg Car: 2004 STi Location: Florida Posts: 887 IWSTI Addict since: Feb 2004 Trader Rating: (0)	Great link. Wish I had known the Nismos were the same when I bought mine. Could have saved a few bucks.

02-19-2006, 11:31 AM	#56
daemon The Next Petter Solberg Car: 2004 STi Location: Florida Posts: 887 IWSTI Addict since: Feb 2004 Trader Rating: (0)	At idle, warm or cold (as cold as a cold start can get here in Floriday), it looks like I'm stuck at 1.54. Does this make sense? Were you expecting this or something else?

02-19-2006, 11:54 AM	#57
WolfPlayer Moderator & ECU Tech Car: 05 CGM STI Fav Mod: mo boostaz Location: Fredneck, MD Posts: 3,730 IWSTI Addict since: Jun 2004 Trader Rating: (6)	Holy reproduction Batman Mine is 1.54 also in both of the logs that I have reviewed (car fully warmed up such that the idle has dropped down to a warm idle). However, these logs were not taken when the RPM oscillation was that noticeable for me. I need to wait for a warmer day. It just chilled down into the 20's today ......... Brrrrrrrrrrr. And we are suppose to do motor mounts on my buddy's car tonight. t

02-19-2006, 02:16 PM	#59
daemon The Next Petter Solberg Car: 2004 STi Location: Florida Posts: 887 IWSTI Addict since: Feb 2004 Trader Rating: (0)	BTW, this is how I picked the 2v-3v area to play with on the intake calibration. I really need to tweak it a little better, but the quick expirement showed that it seemed to have the desired effect. Before... After...