I like it. I really like it. I will most certainly be trying this out!
Oh joy, a MBC, a WGA, ideas for solenoid bypass systems for MBC... and now this. I just can't decide!
If I do it, I'll post results.
__________________
2004 E-Blue SRT-4, totaled by a speeding 18 year old on May 19th 2007
Quote:
I was at the mall today when this guy rolls up in a dodge viper. I was like WOW!!!! Then he tells me that theres some stickers that if you put them in the right place add horsepoewr. I though he was just pulling my leg but then he told me that thers some chemicals in the adhesive that do this...
I drive a 98 civic lx with a tuned automatic transmission.
Bump, need some wizards now dasmopar, aaronneon, dansrt4, vector maybe??
I was wondering how i came up in here ......Honestly i give the guy a pat on the back for messing with it to try. First look at the dyno i am sure everybody cought the peak numbers. And they look pretty decent for the amount of time and money that would be invested. The graph even on smoothing 5 still is a lil shaky. I cant see it staying that way though over time. The PCM is one smart cookie. As blackbird brought up its going to mess with fuel trims a bit ofcourse. Problem is is that depending on weather your going to run into knock from high AIT or running lean. Its kinda like trying to add a piggyback and keep PCM controled boost it dosent really work well once the temp changes at all. Running this will make your car run very inconsistant generally due to weather. Your car might run good today at 70deg out but run like crap or less as well when temps are 10-15 des either way. Like i said atleast you tried and your efforts are appreachated.
__________________
2nd Fastest stock turbo no n2o in the country.
Best 60 1.662
Best 1/8 7.55/93
Best 1/4 11.865/116
Best MPG 28.1 city/33 highway
3147 7.49/102 11.51/124 so far 28psi
3147 7.26/100 22psi pump full int
Thanks for the info i think this is very worth looking into, and will be playing with it soon as i am installing my lc-1, big fmic and i just got my cold air intake done but i havent selected were i want to install the first temp sensor. I as you see live in canada and have driven my car in -30 deg C temps it does in fact hold boost back a lot when it is cold out!
Heres the proof as to what happens when you increase the intake temps that the PCM thinks it sees. Tests were done using 3.91K ohms at the firewall and 3.32K ohms at the throttlebody. This gives the PCM the idea that the air heats up a little as it goes through the system, which is realistic.
Tests were performed in 70*F which is a good "practical" temperature. Lower temperatures will probably provide more power and higher temps will provide less power.
Whats it do?. There has been much speculation that the SRT-4 PCM will increase boost at higher temperatures to make up for the fact that hot air is less dense (less air in a given volume) thus less potential for horsepower. Because our PCM shoots for a horsepower goal, it increases the boost at higher temps to make up for the less dense air. So during the summer you may see boost levels of say 14-15, but during the winter maybe only 11-12 PSI.
On most cars this wouldn't be that big of a deal, because most cars manage their fuel a little better. Our cars however run pig rich, and this is what I wanted to test. Because the PCM would see a very high intake temp it would increase the boost pressure by several PSI, but would most likely not increase the fuel at all. So the question was, did the car run rich enough that the extra air could offset the fuel and make more power while keeping safe air fuel ratios.
Why do this? Basically this is doing the same thing as all the other boost "mods" out there. It increases the boost a couple PSI, just like a boost controller or a WGA or the other "ghetto" mods. The difference is that the PCM is doing the boosting here, so partial throttle boost stays the same and the PCM is happy without the need for map clamps. It requires two resistors which will probably cost somewhere between $0.20 and $2 depending on if you can buy individual or packs. It also takes a matter of minutes to do this.
Anything to worry about? Yes. As I had seen when I first attempted this, the PCM lets the wastegate close very liberally at first. Which means on a stock turbo at 3-3.5K RPM you can hit 25 PSI for a split second very easily. If you ease the throttle on instead of mashing it, the turbo behaves a little better. As a result you run very lean for that small amount of time. Its not on the dyno chart below but I saw something like 17 A/F Ratio, but then dropped down to 12 across the board. This could be remedied by trying higher resistence resisters (lower simulated temps)....though it will affect the overall boost schedule. But there may be a good balance point.
So this might be a great mod for Stage 3 (which I will also dyno after I install Stage 3) because S3 also runs pig rich and the turbo is slightly bigger so the wastegate may be able to control it better. Using 2.5K resistors at both ends I was able to maintain 17 PSI all the way out...so that may be a good option for using a 50 trim on say Stage 2 and keeping full PCM drivability.
Anyways I'm sure your ready for the dyno results. Only mods are 3" BDJ's CAI, BDJ's FMIC, and the very back section of the stock exhaust removed (opens right behind rear axle). Basically mods that really shouldn't have any real benefit on a Stage 0 & stock turbo on a dyno.
As you can see....almost 250HP on a S0 car with almost no mods. The torque kept getting false readings towards the end, so that is why the torque is cut off on the base run. These runs were done 5 minutes apart. We ran baseline, turned off motor, I installed resistors, turned on car and ran 2nd dyno.
With Stage 2 to provide extra fuel and a 3" exhaust, this would probably be pretty good.
Are you saying retarding the timing will promote knock? I would have to say i dont think it will. Reason, retarted timing does increase egt's but reducess cyl presure and causes the flame to burn later and that is the reason the egt's increase because the flame is burning closer to the egt sensor. but this is why egt's are not used to moniter knock they can be related but sometimes are not. another eg. if you run pig rich you can see egt's skyrocket and for the reason that the fuel is still burning out the pipe! I am not trying to start another fight with you. you seem full of good acurate knoldge and have give me tips my self, just thought i should get you thinking!
Quote: Originally Posted by blackbird_R/T
Quote: Originally Posted by westrock
If the PCM goes into open mode when WOT, it will never know the air fuel ratios either before or after.
But if it's going off tables such as the fuel trim cells and they get altered it may correct for it somewhat even at WOT. Without knowing the PCM programming we can only guess or test and reverse engineer what its doing.
I don't think anyone is getting too defensive, just discussing. The curves on the car do look somewhat odd but I bet the results would be comparable on another car. It would be nice to what happens on a properly running car. I'll have to put some thought into the potential effects and the pro/cons of it on my drive home tonight. It isn't exactly like a manual boost controller, MAP clamp, etc., but the results may be similar. As for the A/F it was just a comment that you might be careful about running over 12:1 on a dyno with any type of modification including this one. Right now you don't have the fuel to support that extra boost (and even more so out on the street).
And timing is important, particularly on a car that's already heavily modified and might try something like this. For example, if for some reason someone tried this in combination with a MBC they could already be running lean and the decreased timing would increase EGT's, which would increase the chance of knock. Everything affects something else and is in itself being effected upon.
I don't care only what vendors say and their testimonials and dyno graphs, but I like to see the overall picture of how an engine is running and how it's making the power. That's why I would like to see how the IAT is affecting timing in addition to the effects on boost, A/F and overall power. More knowledge makes it easier to figure out the cause—affect relationships. Keep up the good work and post what you find. Perhaps someone in your area with a scan tool can help find out some more insight in what's going on. The last car that I tried to trick the PCM via IAT changes turned out to not to even have any of the O2 sensors plugged in! And it was running surprisingly well with like that with a big turbo and S-AFC.
would this be a good mod for someone who has (stage2, 255 fuel pump, (fuel), agp wastegate - with pcm out of loop, manual boost controller. Also to monitor and help tune, aem wideband, srt egt guage, safcII.
what do you meen pcm out of loop? do you have stand alone? I would say it looks like another way to trick the ecu into alowing us to try to tune our a/f, boost, and timing. but if you have stand alone you might have that already!
Quote: Originally Posted by spool4u
would this be a good mod for someone who has (stage2, 255 fuel pump, (fuel), agp wastegate - with pcm out of loop, manual boost controller. Also to monitor and help tune, aem wideband, srt egt guage, safcII.
hmm.. makes sense.. has anyone used wideband to see the ratio on this mod yet?
are you kidding me??? Did you see the graph posted? Not something I would want to be driving.....
PCM found out what happend, and you lost ~40whp & 70 ft/lbs torque
Ok I am confused by you saying it lost 40whp and 70ft/ibs of torque. I am not saying you are wrong but I dont see it. It appears as though the graph shows the exact same pattern albiet higher with the modification.
Second I may have just missed it, but how long did it take for you to perform the mod? Is it feasable to just make a quick change at the track? If so next month or so I will make 4 runs, stock, modded, stock, modded and see what happens. If I can run off with a data acquisition tool and get some readings I will post them. After all while the dyno is nice the track will give a more unbiased answer to wheather or not it makes a difference.
Finally our cars a very temperature sensitive. They react to coolant temp, and external temps far more than any car I have seen so it might just work, especially as a "for this run only mod."
The dyno operator did pull one. I told him to turn off the car while he went and got the dyno computer ready for the next run. I unplugged the IAT sensor, plugged in the resistor (I already had it in a baggy bent to the right shape) and he started up the car and did the pull....4-5 minutes max between the dyno pulls. Just a 20" or so circular fan blowing on the engine during that time so the engine didn't cool down or anything.
__________________
-David
06 Lotus Exige
280HP Supercharged 1.8L 05 Black SRT-4 (sold) 330HP & 307TQ @17 PSI (mods in pic)
would this be a good mod for someone who has (stage2, 255 fuel pump, (fuel), agp wastegate - with pcm out of loop, manual boost controller. Also to monitor and help tune, aem wideband, srt egt guage, safcII.
Would this mod help me what so ever?
No. Anything gained by this can easily be figured out by the pcm another way. It did it so fast on the dyno you see the spike and the dip after. You dont want a spiky curve. You want a nice smooth one. If it looks like a heart monitor thats bad. Again it was nice of the thread poster to look into this.
No. Anything gained by this can easily be figured out by the pcm another way. It did it so fast on the dyno you see the spike and the dip after. You dont want a spiky curve. You want a nice smooth one. If it looks like a heart monitor thats bad. Again it was nice of the thread poster to look into this.
Well if someone else would like to try and do a before and after they are welcome to.
SO did you just pull out the stock temp sensor's and replace them with the 2.5 Kohm resistors i was doing some research to see how i would do this mod and found out these specs on the sensors one from the airbox and the one from the throtle body at 76 deg f they boath mesured 10.49 k ohm's, the airbox sensor mesured 6.64 k ohm's at 90 deg f, and 24.3k ohm's at 40 deg f, the throtle body sensor mesured 7.53 k ohm's at 84 deg f and 1.3 k ohm's at 140 deg f they seem to be the same sensors the airboz one just has a protective cover on it! hope this might help some of you! I actualy put a 1-45k ohm pot in paralell with the throtle body sensor so i can tune it to where i want.
Heres the proof as to what happens when you increase the intake temps that the PCM thinks it sees. Tests were done using 3.91K ohms at the firewall and 3.32K ohms at the throttlebody. This gives the PCM the idea that the air heats up a little as it goes through the system, which is realistic.
Tests were performed in 70*F which is a good "practical" temperature. Lower temperatures will probably provide more power and higher temps will provide less power.
Whats it do?. There has been much speculation that the SRT-4 PCM will increase boost at higher temperatures to make up for the fact that hot air is less dense (less air in a given volume) thus less potential for horsepower. Because our PCM shoots for a horsepower goal, it increases the boost at higher temps to make up for the less dense air. So during the summer you may see boost levels of say 14-15, but during the winter maybe only 11-12 PSI.
On most cars this wouldn't be that big of a deal, because most cars manage their fuel a little better. Our cars however run pig rich, and this is what I wanted to test. Because the PCM would see a very high intake temp it would increase the boost pressure by several PSI, but would most likely not increase the fuel at all. So the question was, did the car run rich enough that the extra air could offset the fuel and make more power while keeping safe air fuel ratios.
Why do this? Basically this is doing the same thing as all the other boost "mods" out there. It increases the boost a couple PSI, just like a boost controller or a WGA or the other "ghetto" mods. The difference is that the PCM is doing the boosting here, so partial throttle boost stays the same and the PCM is happy without the need for map clamps. It requires two resistors which will probably cost somewhere between $0.20 and $2 depending on if you can buy individual or packs. It also takes a matter of minutes to do this.
Anything to worry about? Yes. As I had seen when I first attempted this, the PCM lets the wastegate close very liberally at first. Which means on a stock turbo at 3-3.5K RPM you can hit 25 PSI for a split second very easily. If you ease the throttle on instead of mashing it, the turbo behaves a little better. As a result you run very lean for that small amount of time. Its not on the dyno chart below but I saw something like 17 A/F Ratio, but then dropped down to 12 across the board. This could be remedied by trying higher resistence resisters (lower simulated temps)....though it will affect the overall boost schedule. But there may be a good balance point.
So this might be a great mod for Stage 3 (which I will also dyno after I install Stage 3) because S3 also runs pig rich and the turbo is slightly bigger so the wastegate may be able to control it better. Using 2.5K resistors at both ends I was able to maintain 17 PSI all the way out...so that may be a good option for using a 50 trim on say Stage 2 and keeping full PCM drivability.
Anyways I'm sure your ready for the dyno results. Only mods are 3" BDJ's CAI, BDJ's FMIC, and the very back section of the stock exhaust removed (opens right behind rear axle). Basically mods that really shouldn't have any real benefit on a Stage 0 & stock turbo on a dyno.
As you can see....almost 250HP on a S0 car with almost no mods. The torque kept getting false readings towards the end, so that is why the torque is cut off on the base run. These runs were done 5 minutes apart. We ran baseline, turned off motor, I installed resistors, turned on car and ran 2nd dyno.
With Stage 2 to provide extra fuel and a 3" exhaust, this would probably be pretty good.
I recently installed a lc-1 in my car and started to log data and learn about some more of what is going on with my car i have a big fmic and cold air intake. I noticed at 2000 rpm in third i can pin it and the a:f will hit about 12.6 to 12.7 before for a very short time till the boost starts then the a:f will drop to about 10.8 this is at 15-16 ps boost and about 80 deg outside i have my closed loop tuned to 16:1 - 16.7:1 don't tell me about how scary that is i have my reasons for that and no it is not hurting the engine but I thought I would say that because I am not sure if over time the ecu recurves the a:f acording to the closed loop readings it sees! Any ways the moral of the story 12.7:1 a:f is a rule of thumb for max power and if you trick the ecu with the temp mod it will be lean at that spot( under little or no boost) till the turbo spools! I would say a map clamp is still better or what i am about to do is make the ecu stay closed loop all the time and use my second out put off of the lc-1 for power with a boost switch so output 1 will be set for econamy and #2 will be for power and at a couple of psi it will switch to the richer one then i will clamp the tps and map to get it to stay closed loop!
If the PCM goes into open mode when WOT, it will never know the air fuel ratios either before or after.
Boost controllers, aftermarket WGA and mapclamps all do the same thing. They allow more boost to go into the engine than the PCM would allow. The engine may not pull timing with those, but pulling timing does not hurt a motor. However I don't know if any manufacture on here shows what the timing is doing with there product despite the gains in power. At this point we don't even know that timing is being pulled at all...it may just wait for a knock signal before it starts.
It may get higher AFR's on the highway, because due to the increased rolling resistance and air friction there will be more load on the turbo and possibly (slightly) more boost as a result. I don't see how that would be any different than any of the other parts I listed above.
Also this was on a totally stock Stage 0 car. If you get any of the stage upgrades or a fuel line return kit which many poeple do you will get increased fuel flow, thus a safer margin. Also this "mod" is adjustable so you can raise the values to make it a little richer.
I'm not trying to tell you guys that the other forms of boost regulators suck, I'm just giving you more options. I made that clear in the beginning.
I appreciate your experiment! Here's some info I've gathered over the last two years or so that may help out. I've been datalogging this car since the day I picked it up, so here is my $.02 on the subject....
As per your post in the quote, the car DOES lower timing with increased boost. On a hot day at 15-16 PSI dropping to 12 my timing goes from 18* to 26* at redline. On a cold day with bost from 14 to 11@ redline the timing was 22* to 30*. With the boost set to 17PSI dropping to 15@ redline timing is 16* to 20*. The first two were on a consistant basis with the stock wastegate and unmodified car. The higher boost results were documented after the PCM had time to adjust to the changes (modified stock wastegate).
When I get spark knock, the timing goes from the mid 20's to low teens sharply. There is a big difference in pulling timing from high boost and pulling timing from knock on the graphs. Sometimes it gives the timing back quickly and somtimes it doesn't, depending on the serverity. Also, when the MAP is maxed out (above 18PSI) over 4500 RPM, it pulls timing fast, and tries to get boost under control. This is usually why the boost goes back to normal with a modified WG using the stock WG seloniod after a few 4th gear pulls.
I have one question about your temp changes......was the MAP clamped when you did the temp sensor change? IMHO, if you didn't, then the MAP would over-ride that by being maxed out and dropping boost and/or timing to get it back into control, regardless of intake temp.
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......Honestly i give the guy a pat on the back for messing with it to try. First look at the dyno i am sure everybody cought the peak numbers. And they look pretty decent for the amount of time and money that would be invested. The graph even on smoothing 5 still is a lil shaky. I cant see it staying that way though over time. The PCM is one smart cookie. As blackbird brought up its going to mess with fuel trims a bit ofcourse. Problem is is that depending on weather your going to run into knock from high AIT or running lean. Its kinda like trying to add a piggyback and keep PCM controled boost it dosent really work well once the temp changes at all. Running this will make your car run very inconsistant generally due to weather. Your car might run good today at 70deg out but run like crap or less as well when temps are 10-15 des either way. Like i said atleast you tried and your efforts are appreachated.
Perhaps someone in your area with a scan tool can help find out some more insight in what's going on. The last car that I tried to trick the PCM via IAT changes turned out to not to even have any of the O2 sensors plugged in! And it was running surprisingly well with like that with a big turbo and S-AFC.
Not something I would want to be driving.....
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