Crawford Plenum causing engine to run lean/retard timing w/o TS flash?
Crawford Plenum causing engine to run lean/retard timing w/o TS flash?
The questions/issues presented here are mainly directed to Adam and/or Chris from Crawford and Cheston from Technosquare. Any other input is certainly welcome as this relates to many members here.
The following excepts are from this thread on Freshalloy.com:
http://forums.freshalloy.com/ubbthre...b=5&o=&fpart=1
The questions:
1. Does the Crawford plenum cause any type of lean condition in the engine which is recognized by the ECM?
2. If so, does the ECM retard timing to compensate?
3. Are there separate TS flashes available for those with and without the plenum?
4. Is an ECM flash neccessary for optimun engine health and performance when using the Crawford plenum or does the flash simply optimize the mod and keeping the ECM stock with the plenum is just fine for those that don't want to flash their ECM?
Anything I'm missing? Feel free to add more.
Thought on this are appreciated and I'm posting here as many of you have the plenum and/or TS flash and would likely take interest in the topic. Plus the Crawford and TS guys don't get over to FA much.
The following excepts are from this thread on Freshalloy.com:
http://forums.freshalloy.com/ubbthre...b=5&o=&fpart=1
Scribe:
Our engines run rich with the stock plenum, but with the Crawford they actually run on the lean side at higher RPMs because of the increased air flow. Technosquare's computer program for engines with the Crawford plenum corrects this and gives you a consistent A/F ratio of 12.5 all the way up to the new 7100 RPM redline.
Our engines run rich with the stock plenum, but with the Crawford they actually run on the lean side at higher RPMs because of the increased air flow. Technosquare's computer program for engines with the Crawford plenum corrects this and gives you a consistent A/F ratio of 12.5 all the way up to the new 7100 RPM redline.
MustGoFastR:
Crawford's modified plenum reduces the 30% deficit in airflow to the front cylinders to 5% and does not change flow to the rear cylinders at all (there is some increase to the middle two). Given this, there is still 5% less air going to the front cylinders, therefore they are still running richer than the rears. Why would there be a lean condition at high RPMs? Even if there was, the rear cylinders, which airflow is unaltered to, would be running the leanest as they get the most air. This being the case, it would then also be an issue with a stock plenum, would it not? I don't think Nissan designed their engines to run lean to any extent that would be harmful to them.
Crawford's modified plenum reduces the 30% deficit in airflow to the front cylinders to 5% and does not change flow to the rear cylinders at all (there is some increase to the middle two). Given this, there is still 5% less air going to the front cylinders, therefore they are still running richer than the rears. Why would there be a lean condition at high RPMs? Even if there was, the rear cylinders, which airflow is unaltered to, would be running the leanest as they get the most air. This being the case, it would then also be an issue with a stock plenum, would it not? I don't think Nissan designed their engines to run lean to any extent that would be harmful to them.
Scribe:
First of all, I'm not an engineer and I didn't do my own flow bench measurements. This information was conveyed to me by Tadashi, the technician at Technosquare who did my upgrade.
I, too, had assumed that the Crawford would alleviate the rich running condition in the stock plenum and result in an ideal A/F ratio.
However, apparently, that isn't the case, since Tadashi said that it had been necessary to richen the mixture to achieve the ideal ratio. Please note that I never said that it was running so lean as to pose potential harm to the engine, only that the engine was not making all the power that was possible because of the lean condition. And making power is the whole point of this upgrade.
First of all, I'm not an engineer and I didn't do my own flow bench measurements. This information was conveyed to me by Tadashi, the technician at Technosquare who did my upgrade.
I, too, had assumed that the Crawford would alleviate the rich running condition in the stock plenum and result in an ideal A/F ratio.
However, apparently, that isn't the case, since Tadashi said that it had been necessary to richen the mixture to achieve the ideal ratio. Please note that I never said that it was running so lean as to pose potential harm to the engine, only that the engine was not making all the power that was possible because of the lean condition. And making power is the whole point of this upgrade.
ChrisG35C:
My understanding is that the standard Technosquare program will not be setup for optimal performance when using a Crawford plenum. They have to modify thier settings to accomodate the Crawford plenum. The stock ECU programming works fine with the plenum. So if you go with Technosquare, make sure they know you have a plenum so they can give you the proper version of the ECU upgrade.
My understanding is that the standard Technosquare program will not be setup for optimal performance when using a Crawford plenum. They have to modify thier settings to accomodate the Crawford plenum. The stock ECU programming works fine with the plenum. So if you go with Technosquare, make sure they know you have a plenum so they can give you the proper version of the ECU upgrade.
The Bellox:
From what I have gathered,
the stock ECU doesnt have enough range (if any) in the fuel map to compensate for the plenum with just fuel, it has to start retarding the timing.
From personal experience,
the plenum will make the engine run noticably lean right after its put on. I pulled out of my driveway and was WOT within a couple of minutes and could feel and hear the engine starving for fuel in the top-end. Of course it wasnt fully warmed up which leaned it out even more. The next day it ran much better, once the ECU knew what to do.
Whats weird, I never heard of the "special crawford" flash on any of the Z-forums either. The way I've understood it is their one flash program should cover any N/A set-up and the ECU will tune itself with the bigger fuel map ranges, without retarding the timing.
From what I have gathered,
the stock ECU doesnt have enough range (if any) in the fuel map to compensate for the plenum with just fuel, it has to start retarding the timing.
From personal experience,
the plenum will make the engine run noticably lean right after its put on. I pulled out of my driveway and was WOT within a couple of minutes and could feel and hear the engine starving for fuel in the top-end. Of course it wasnt fully warmed up which leaned it out even more. The next day it ran much better, once the ECU knew what to do.
Whats weird, I never heard of the "special crawford" flash on any of the Z-forums either. The way I've understood it is their one flash program should cover any N/A set-up and the ECU will tune itself with the bigger fuel map ranges, without retarding the timing.
1. Does the Crawford plenum cause any type of lean condition in the engine which is recognized by the ECM?
2. If so, does the ECM retard timing to compensate?
3. Are there separate TS flashes available for those with and without the plenum?
4. Is an ECM flash neccessary for optimun engine health and performance when using the Crawford plenum or does the flash simply optimize the mod and keeping the ECM stock with the plenum is just fine for those that don't want to flash their ECM?
Anything I'm missing? Feel free to add more.
Thought on this are appreciated and I'm posting here as many of you have the plenum and/or TS flash and would likely take interest in the topic. Plus the Crawford and TS guys don't get over to FA much.
Registered User
Joined: Jun 2002
Posts: 800
Likes: 1
From: Long Beach, CA
CHeston always said that if you add the Crawford to your TS flashed Z, you have to have it reflashed to compensate for it. So yeah, there are TS flashes for with and without Crawford. Last time I read, he said that they were waiting for Crawford to send them a plenum so that the flash could be developed. I'm sure that's already done.
Nothing is needed to a non flashed car. If you do want a T/S ECU flash, tell them you have a plenum. T/S will cater to your individual mods, if they know about them (albeit a guessing game if they have not tested on test car). I have not heard of any customer cars (non test cars) running lean because of the plenum. I have heard rumors of the plenum and ECU running "leaner" than stock but not to a point where it was dangerous. I have also heard rumors of the test (pre-release) ECU and plenum running even leaner, but that’s what testing is for. Remember our mod is not customizable, theirs is. It’s a give and take situation when it comes to engine management modifications. Every car can be different.
BTW, how is the FX? You could update the sig, or did you go back to the G?
BTW, how is the FX? You could update the sig, or did you go back to the G?
Last edited by VandyZ; Oct 14, 2003 at 09:56 AM.
Originally posted by Zakira
CHeston always said that if you add the Crawford to your TS flashed Z, you have to have it reflashed to compensate for it. So yeah, there are TS flashes for with and without Crawford. Last time I read, he said that they were waiting for Crawford to send them a plenum so that the flash could be developed. I'm sure that's already done.
CHeston always said that if you add the Crawford to your TS flashed Z, you have to have it reflashed to compensate for it. So yeah, there are TS flashes for with and without Crawford. Last time I read, he said that they were waiting for Crawford to send them a plenum so that the flash could be developed. I'm sure that's already done.
So basically what I'm getting is that the plenum may or may not cause the engine to run slightly leaner than stock with the stock ECM. If it does, it is not to the extent of being any danger to the engine or enough to cause the ECM to retard timing (and it certainly doesn't hurt performance any). The TS flash can bring it's own gains to the car, but if it is being run in conjunction with the plenum, it needs to be programmed to take that into account for the two to function properly together.
Thanks for the replies, guys. I'll share this info. at Freshalloy. The FX is doing great; thanks for asking, Adam. Been too lazy to update the sig and Avatar, but I'll get around to it. I love how well it runs with the plenum, extended Z tube, Stillen intake and 7 wire grounding kit; it's a whole new beast. Just curious; how many FX owners have ordered the plenum?
Thanks for the replies, guys. I'll share this info. at Freshalloy. The FX is doing great; thanks for asking, Adam. Been too lazy to update the sig and Avatar, but I'll get around to it. I love how well it runs with the plenum, extended Z tube, Stillen intake and 7 wire grounding kit; it's a whole new beast. Just curious; how many FX owners have ordered the plenum?
Originally posted by MustGoFastR
So basically what I'm getting is that the plenum may or may not cause the engine to run slightly leaner than stock with the stock ECM. If it does, it is not to the extent of being any danger to the engine or enough to cause the ECM to retard timing (and it certainly doesn't hurt performance any).
So basically what I'm getting is that the plenum may or may not cause the engine to run slightly leaner than stock with the stock ECM. If it does, it is not to the extent of being any danger to the engine or enough to cause the ECM to retard timing (and it certainly doesn't hurt performance any).
Originally posted by MustGoFastR
The TS flash can bring it's own gains to the car, but if it is being run in conjunction with the plenum, it needs to be programmed to take that into account for the two to function properly together.
The TS flash can bring it's own gains to the car, but if it is being run in conjunction with the plenum, it needs to be programmed to take that into account for the two to function properly together.
Originally posted by MustGoFastR
Just curious; how many FX owners have ordered the plenum?
Just curious; how many FX owners have ordered the plenum?
You have done good. Lets leave it at that! Doug just raves about your post on freshalloy.com.
Trending Topics
Originally posted by MustGoFastR:
Just curious; how many FX owners have ordered the plenum?
Just curious; how many FX owners have ordered the plenum?
Originally posted by VandyZ:
You have done good. Lets leave it at that! Doug just raves about your post on freshalloy.com.
You have done good. Lets leave it at that! Doug just raves about your post on freshalloy.com.
I don't suppose I've sent enough business your way to qualify for a "special discount" on a set of Doug's headers when they become available?
Oh, and I think you guys can officially move the FX off of the R&D page of your site. I e-mailed Doug some pics of my setup for you guys to use on the site, too. Let me know if you need more.
Last edited by MustGoFastR; Oct 14, 2003 at 11:29 AM.
Originally posted by Evil350z
My Z ran a perfect 13.3 across the board with our plenum and high-flow cats.
NO FLASH is necessary.
My Z ran a perfect 13.3 across the board with our plenum and high-flow cats.
NO FLASH is necessary.
13.3 is hardly PERFECT. 12.5 is perfect. To be 100% accurate, you need to take pre-cat measurements with the wideband o2 sensor, as the tailpipe MAY (depending on the snsor) show leaner condition (as the fuel get s soaked up by the cat).
Gurgen
Originally posted by gurgenpb01
13.3 is hardly PERFECT. 12.5 is perfect. To be 100% accurate, you need to take pre-cat measurements with the wideband o2 sensor, as the tailpipe MAY (depending on the snsor) show leaner condition (as the fuel get s soaked up by the cat).
Gurgen
13.3 is hardly PERFECT. 12.5 is perfect. To be 100% accurate, you need to take pre-cat measurements with the wideband o2 sensor, as the tailpipe MAY (depending on the snsor) show leaner condition (as the fuel get s soaked up by the cat).
Gurgen
New Member
Joined: Feb 2003
Posts: 2,237
Likes: 1
From: Nashville, TN
Originally posted by gurgenpb01
13.3 is hardly PERFECT. 12.5 is perfect. To be 100% accurate, you need to take pre-cat measurements with the wideband o2 sensor, as the tailpipe MAY (depending on the snsor) show leaner condition (as the fuel get s soaked up by the cat).
Gurgen
13.3 is hardly PERFECT. 12.5 is perfect. To be 100% accurate, you need to take pre-cat measurements with the wideband o2 sensor, as the tailpipe MAY (depending on the snsor) show leaner condition (as the fuel get s soaked up by the cat).
Gurgen
On an NA application 13.1-13.4 is ideal.
Even then, we tested the "cat soaking" condition already... def. an urban legend.
Thanks.
Evil 350Z
Really? I was told that 12.5 under full load is what you want!?
I have got to lean up a little if that's true.
As far as the cat-soaking condition, I think you maybe right. We did it both ways at TechnoSquare when we were testing my G with the new ECu, got the same reading both ways. But I heard that some of the poorer o2 sensors can give a different result.
Can you PLEASE elaborate on the A/F mixture. What is your source for the 13.1-13.3 ratio being ideal?
I have 5AT G35 sedan, and with this setup (se my sig), my car is pulling 241 rwhp. This is on the same dyno used for the exhaust shootout of the strictly Z magazine (where the nontrack Z 6MT scored 233 rwhp).
I would not say that's DISAPPOINTING, but I am very open minded about these things, maybe i need to lean up to 13.3. Pleas inform.
Gurgen
Really? I was told that 12.5 under full load is what you want!?
I have got to lean up a little if that's true.
As far as the cat-soaking condition, I think you maybe right. We did it both ways at TechnoSquare when we were testing my G with the new ECu, got the same reading both ways. But I heard that some of the poorer o2 sensors can give a different result.
Can you PLEASE elaborate on the A/F mixture. What is your source for the 13.1-13.3 ratio being ideal?
I have 5AT G35 sedan, and with this setup (se my sig), my car is pulling 241 rwhp. This is on the same dyno used for the exhaust shootout of the strictly Z magazine (where the nontrack Z 6MT scored 233 rwhp).
I would not say that's DISAPPOINTING, but I am very open minded about these things, maybe i need to lean up to 13.3. Pleas inform.
Gurgen
Thread
Thread Starter
Forum
Replies
Last Post
HoneyBadgerRy
2003-2009 Nissan 350Z
8
Sep 21, 2015 03:25 PM
