Good talking to you the last couple days Jason. On the idle hang issue, I noticed a post on it on the Gen. I/II forum right now where Sean Roe again stated that there is idle hang programmed into the factory PCM that kicks in when the car is moving but not in gear (like coasting up to a redlight), which is exactly when I used to notice it. Do you have the capability to look through the JTEC programming and figure out where it is?
PCM Programming now available!!! L@@K!!
- Thread starter WESTCOAST JASON
- Start date
WESTCOAST JASON
Enthusiast
I have not found an idle hang setting per'se. There is a throttle following parameter that makes driveability nice. For example, when you let off the gas it does not feel like you shut the key off. This can be tweaked, but Chrysler seems to have done a pretty good job with it. The problem of idle hangs really seem attributed to modified cars and each one needs to be re-mapped around its modifications. A fix on a big cam car may not work right on a super charged car. (Wish one fix did work for all, would be easy to do the PCM's!)
WESTCOAST JASON
Enthusiast
Sure did! You should have gotten a tracking number in your email direct from my shipper. thanks!
WESTCOAST JASON
Enthusiast
Viper truck PCM tune for headers coming soon along with PCM tune for heads/cam mods. Both should be ready in about 5 weeks.
PhoenixGTS
Enthusiast
After this thread being dead for a month, let me start it back up. I recently discovered I have a Mopar HP PCM so that is my baseline. I put the WCV PCM in last night. Went for a little test drive and this is what I found. Peak power is probably not very much different (barely measurable on the “butt dyno”), but with the Mopar HP PCM I had a big flat spot from about 2,500 rpm to 3,500 rpm after which the engine would hit. I really felt like a turbo car. The 70mm throttle bodies could be part of the blame. So far the WCV unit seems to fix that flat spot in the power band so that now there is a nice linear run from idle to the redline. Seat of the pants tells me there could be a significant torque improvement at 3k rpm. Maybe even 40 ft pounds or so. Perhaps it is more fuel in the mid-range, or maybe the Mopar was yanking timing for some reason. Very nice so far, and although it was warmer than it has been this morning, cold start was nice and smooth. One thing I DO NOT LIKE is the higher idle. Sounds like shyte. I loved the lopey Harley sound on the stock idle and Belanger exhaust. Now it has kind of a rolling wump-wump-wump with a kind of drone (might be helpful if you have a light flywheel??). After I get some dyno results and see A/F ratios, perhaps I can get WCV to do some tweaks and bring that idle back down at the same time.
And about that dyno. My girlfriend got me an hour of dyno time at a facility about two miles from the house, so I am going to use the time to compare the Mopar HP PCM to my 91 octane WCV programming. It might be three weeks or so before I get to the dyno, but I will for sure post the results.
One more thought. Since you can change the PCM in five minutes, it seems to me that if WCV could write an aggressive program to utilize 100 octane fuel that it would be easier to have two WCV PCMS than trying to tune a VECII for normally aspirated guys. I bet they could get 40-50 hp with the aggressive timing allowed by good gas.
And about that dyno. My girlfriend got me an hour of dyno time at a facility about two miles from the house, so I am going to use the time to compare the Mopar HP PCM to my 91 octane WCV programming. It might be three weeks or so before I get to the dyno, but I will for sure post the results.
One more thought. Since you can change the PCM in five minutes, it seems to me that if WCV could write an aggressive program to utilize 100 octane fuel that it would be easier to have two WCV PCMS than trying to tune a VECII for normally aspirated guys. I bet they could get 40-50 hp with the aggressive timing allowed by good gas.
PhoenixGTS
Enthusiast
Pre-dyno follow-up: after a 1,000 idle hang free miles with my Mopar Performance PCM, now that I installed the WCV unit the car is idle hanging worse than ever, You have to come to a complete stop, then after a second the idle finally drops. I am going to re-adjust the throttle-bodies this weekend to see if it helps, but if not, this *****.
cgmaster
Viper Owner
To Phoenix GTS did you ever dyno your car to compare the Mopar unit and the WCV unit. I am curious about the results.
PhoenixGTS
Enthusiast
I am hoping to hit the dyno in early February. The car is definitely faster with the WCV unit in, but it idle hangs SO BAD that I had to take it out and re-install my Mopar Performance PCM. Absolutely no hang with the Mopar unit.
BLWNASP
Enthusiast
I am interested to see what happens with this, keep us posted, please.
PhoenixGTS
Enthusiast
WCV PCM idle hang update. Talked to John at WCV for awhile today (he is super-Viper tech BTW) and he is of the mind that idle hang is greatly influenced by throttle body synchronization. I told him about how I adjusted the t-bodies and went for test drives. He pointed out that I was following a faulty procedure: 1) the throttle bodies cannot be synch'd manually, only electronically using what he called a DRB diagnostic procedure that uses the available electronic sensors to determine the amount of air making it past the t-body blades at idle; and 2) each time you make an adjustment, you have to de-power the PCM for a full ten minutes so that it will take a brand new look at the re-synch'd t-bodies and make its idle hang decisions from the new baseline.
I will be playing with this week to see if I can get lucky with the synch and get the ECU running idle free, but in any event I am scheduled for the Mopar Perf PCM vs. WCV PCM dyno battle on Friday night and should be able to post the results this weekend.
I will be playing with this week to see if I can get lucky with the synch and get the ECU running idle free, but in any event I am scheduled for the Mopar Perf PCM vs. WCV PCM dyno battle on Friday night and should be able to post the results this weekend.
PhoenixGTS
Enthusiast
Finally - dyno results WCV PCM vs. Mopar performance PCM
Made it to the dyno last night in low pressure (28.5 on barometer) but cool (ambients in 60Fs) conditions. Here is the overview I posted on the GenI/II forum: Short Version is WCV PCM and Mopar Perf PCM tied at 415rwhp/475rwtq on Dyno Dynamics dyno.
My 98 GTS has the basic bolt-on mods in my sig. Probably only twist different from most bolt-on cars is the 70mm throttle bodies (don't flame me - they came with the car). My car came to me with a Mopar Performance PCM in place. Car ran fine. Had idle hang, but adjusting the throttle body synchronization stopped that completely and permanently. Idled very low and sounded like a Harley. In driving it always seemed like it had a flat spot in the mid-range then would hit like a turbo car about 3,500 rpm. I blamed the big throttle bodies. In an effort to see if software might be a good next step, I purchased a West Coast Viper tuned PCM from RedSled. It has a program designed for 91 octane fuel and passing California emissions (whatever that means). Installed the WCV unit and found two things: 1) hellish idle hang; and 2) the powerband seemed flatter with out the dip from 2,000 - 3,000 rpm. I have been working on the idle hang issue after consulting with John at WCV, and have put a big dent in it, but I am still having idle hang issues with the WCV that are nonexistent with the Mopar unit.
My girlfriend bought me an hour of dyno time for x-mas. The facility has a Dyno Dynamics all-wheel-drive adjustable load dyno (generally reads lower than a Dynojet). The AZ VCA guys are having a dyno day on February 19th at the same facility so my results will be a nice baseline for them to beat. Went to the dyno last night and here is what I found (sorry but it will take me awhile to figure out how to convert the charts into pics and get them posted).
The horsepower curves of the WCV and Mopar units are absolutely identical in a run from idle. When placed on the same graph and lay right on top of each other. However, they get there with totally opposite methods, and some trickery showed some differences.
We started with the WCV PCM. Rwhp curve is pretty flat from onset to 3,250 rpm after which it steepens making 300 rwhp at 3,500 rpm and a max rwhp of 415 at a surprisingly low 5,000 rpm. The rwtq curve shows a substantial dip from 2,500 to 3,250 making only 400 ft lbs at 3,000 rpm then maxing out at 475 ft lbs at 4,250 rpm. The interesting part of the air/fuel ratio. At the start of the run it comes from lean to a very nicely controlled 12.25-12.5:1 from 2,250 rpm through 5,000 rpm after which it richens up finally ending up richer than 12:1 above 5,500 rpm. This is contrary to the 13:1 John from WCV says he targets on the top end. The WCV A/F plot is very flat. The software is doing its job.
Next was the Mopar Performance PCM. Rwhp and rwtq curves are the same as WCV unit, with the WCV PCM maybe making a few more rwhp above 5,000 rpm, and very surprisingly the WCV unit making a few less ft lbs from 2,500 to 3,250 rpm (contrary to my butt-dyno). Again the interesting part is the air/fuel ratio. At the start of the run it comes from lean to a very jagged plot starting at 11.5:1 at 2,500 rpm, dipping to 11.1:1 at 3,250 rpm, jumping to nearly 12:1 at 3,750 rpm then richening up until it goes gnarly rich at 4,750 rpm after which it is a very fat 10.75:1 or so.
Comparison. We had not way of logging ignition advance, but given the identical power with the WCV unit being substantially leaner than the Mopar unit, the Mopar unit must have significantly more timing. So here we have two very different theories of tuning, WCV leaner with presumably less timing, and Mopar richer with presumably more timing, resulting in the same result. As mentioned above, strange thing was that the dyno did not confirm my seat of the pants feeling that there was a flat spot from about 2,000 rpm to 3,000 rpm with the Mopar unit the was not there with the WCV unit. Rich the dyno operator had an idea to identify the feeling I had, but the regular dyno plots were not showing.
We made runs with both computers that instead of starting from idle, started from a steady 3,000. Now we found a difference. I can only guess that it was because a leaner/less timing philosophy works better from a higher rpm launch, but when starting a dyno run at 3,000 the WCV unit wooped the Mopar unit, making almost 10 rwhp more at 4,000 rpm and 20 hp more at 5,500 rpm. Sorry but I do not have any explanation as to the high rpm differences from making runs from idle as compared to making runs from 3,000. Again, the air/fuel plot is interesting. The WCV unit line comes from lean and settles into a controlled 12-12.1:1 ratio finishing up at a solid 12:1 above 5,000 rpm. The Mopar unit comes from dead rich to a jagged line starting at 11.5:1 at 3,750 rpm and ending up at 10.5:1 above 5,000. Only guess I have is that the different rpm starting point causes the PCMs to choose their air/fuel targets from different tables. Any comments would be greatly appreciated.
They say the dyno doesn't lie. They don't say it won't confuse you. Regarding driveability, the WCV idle hang issue is horrible. If I cannot solve the problem I will not run the WCV PCM. John at WCV say the throttle bodies need to be synch'd using the DRB diagnostic procedure and they have never had a problem with hang. Perhaps I have to break down and get the dealer to do this. In the mean time I will continue to test and see if I can kill the idle hang myself. The higher idle of the WCV unit is horrible. Unless you had some sort of light flywheel stalling issue I see no reason to do this. It takes the great stock lumpy idle that sounds like a Harley, and moves it into a range where the Belanger exhaust has a bit of boom and you end up with a woomp-woomp-woomp that drives you nuts. In actual driving the WCV feels cleaner, snappier, and overall faster especially in the mid-range. I would like to run the WCV unit with no idle hang and the stock idle. Perhaps I'll send it back to WCV and have the idle reduced and a little more timing put in and make it back to the AZ VCA dyno day for a follow up.
Final thoughts. With all the resources of the VCA, and the VCA's friendly relationship with DC, why in the heck can we not identify the engineering team that actually wrote the Gen I and Gen II software so we can see what their goals were, what compromises they might have made for emissions etc, and figure out why an idle hang is programmed in given the presence of certain hardware adjustment parameters? Is that too much to ask?
Made it to the dyno last night in low pressure (28.5 on barometer) but cool (ambients in 60Fs) conditions. Here is the overview I posted on the GenI/II forum: Short Version is WCV PCM and Mopar Perf PCM tied at 415rwhp/475rwtq on Dyno Dynamics dyno.
My 98 GTS has the basic bolt-on mods in my sig. Probably only twist different from most bolt-on cars is the 70mm throttle bodies (don't flame me - they came with the car). My car came to me with a Mopar Performance PCM in place. Car ran fine. Had idle hang, but adjusting the throttle body synchronization stopped that completely and permanently. Idled very low and sounded like a Harley. In driving it always seemed like it had a flat spot in the mid-range then would hit like a turbo car about 3,500 rpm. I blamed the big throttle bodies. In an effort to see if software might be a good next step, I purchased a West Coast Viper tuned PCM from RedSled. It has a program designed for 91 octane fuel and passing California emissions (whatever that means). Installed the WCV unit and found two things: 1) hellish idle hang; and 2) the powerband seemed flatter with out the dip from 2,000 - 3,000 rpm. I have been working on the idle hang issue after consulting with John at WCV, and have put a big dent in it, but I am still having idle hang issues with the WCV that are nonexistent with the Mopar unit.
My girlfriend bought me an hour of dyno time for x-mas. The facility has a Dyno Dynamics all-wheel-drive adjustable load dyno (generally reads lower than a Dynojet). The AZ VCA guys are having a dyno day on February 19th at the same facility so my results will be a nice baseline for them to beat. Went to the dyno last night and here is what I found (sorry but it will take me awhile to figure out how to convert the charts into pics and get them posted).
The horsepower curves of the WCV and Mopar units are absolutely identical in a run from idle. When placed on the same graph and lay right on top of each other. However, they get there with totally opposite methods, and some trickery showed some differences.
We started with the WCV PCM. Rwhp curve is pretty flat from onset to 3,250 rpm after which it steepens making 300 rwhp at 3,500 rpm and a max rwhp of 415 at a surprisingly low 5,000 rpm. The rwtq curve shows a substantial dip from 2,500 to 3,250 making only 400 ft lbs at 3,000 rpm then maxing out at 475 ft lbs at 4,250 rpm. The interesting part of the air/fuel ratio. At the start of the run it comes from lean to a very nicely controlled 12.25-12.5:1 from 2,250 rpm through 5,000 rpm after which it richens up finally ending up richer than 12:1 above 5,500 rpm. This is contrary to the 13:1 John from WCV says he targets on the top end. The WCV A/F plot is very flat. The software is doing its job.
Next was the Mopar Performance PCM. Rwhp and rwtq curves are the same as WCV unit, with the WCV PCM maybe making a few more rwhp above 5,000 rpm, and very surprisingly the WCV unit making a few less ft lbs from 2,500 to 3,250 rpm (contrary to my butt-dyno). Again the interesting part is the air/fuel ratio. At the start of the run it comes from lean to a very jagged plot starting at 11.5:1 at 2,500 rpm, dipping to 11.1:1 at 3,250 rpm, jumping to nearly 12:1 at 3,750 rpm then richening up until it goes gnarly rich at 4,750 rpm after which it is a very fat 10.75:1 or so.
Comparison. We had not way of logging ignition advance, but given the identical power with the WCV unit being substantially leaner than the Mopar unit, the Mopar unit must have significantly more timing. So here we have two very different theories of tuning, WCV leaner with presumably less timing, and Mopar richer with presumably more timing, resulting in the same result. As mentioned above, strange thing was that the dyno did not confirm my seat of the pants feeling that there was a flat spot from about 2,000 rpm to 3,000 rpm with the Mopar unit the was not there with the WCV unit. Rich the dyno operator had an idea to identify the feeling I had, but the regular dyno plots were not showing.
We made runs with both computers that instead of starting from idle, started from a steady 3,000. Now we found a difference. I can only guess that it was because a leaner/less timing philosophy works better from a higher rpm launch, but when starting a dyno run at 3,000 the WCV unit wooped the Mopar unit, making almost 10 rwhp more at 4,000 rpm and 20 hp more at 5,500 rpm. Sorry but I do not have any explanation as to the high rpm differences from making runs from idle as compared to making runs from 3,000. Again, the air/fuel plot is interesting. The WCV unit line comes from lean and settles into a controlled 12-12.1:1 ratio finishing up at a solid 12:1 above 5,000 rpm. The Mopar unit comes from dead rich to a jagged line starting at 11.5:1 at 3,750 rpm and ending up at 10.5:1 above 5,000. Only guess I have is that the different rpm starting point causes the PCMs to choose their air/fuel targets from different tables. Any comments would be greatly appreciated.
They say the dyno doesn't lie. They don't say it won't confuse you. Regarding driveability, the WCV idle hang issue is horrible. If I cannot solve the problem I will not run the WCV PCM. John at WCV say the throttle bodies need to be synch'd using the DRB diagnostic procedure and they have never had a problem with hang. Perhaps I have to break down and get the dealer to do this. In the mean time I will continue to test and see if I can kill the idle hang myself. The higher idle of the WCV unit is horrible. Unless you had some sort of light flywheel stalling issue I see no reason to do this. It takes the great stock lumpy idle that sounds like a Harley, and moves it into a range where the Belanger exhaust has a bit of boom and you end up with a woomp-woomp-woomp that drives you nuts. In actual driving the WCV feels cleaner, snappier, and overall faster especially in the mid-range. I would like to run the WCV unit with no idle hang and the stock idle. Perhaps I'll send it back to WCV and have the idle reduced and a little more timing put in and make it back to the AZ VCA dyno day for a follow up.
Final thoughts. With all the resources of the VCA, and the VCA's friendly relationship with DC, why in the heck can we not identify the engineering team that actually wrote the Gen I and Gen II software so we can see what their goals were, what compromises they might have made for emissions etc, and figure out why an idle hang is programmed in given the presence of certain hardware adjustment parameters? Is that too much to ask?
Re: Finally - dyno results WCV PCM vs. Mopar performance PCM
Nice writeup giving info on what the different units do.
Which gear did you test in?
Do you have Belanger headers, modified stock cats, etc.?
Nice writeup giving info on what the different units do.
Which gear did you test in?
Do you have Belanger headers, modified stock cats, etc.?
PhoenixGTS
Enthusiast
Re: Finally - dyno results WCV PCM vs. Mopar performance PCM
Normally Rich has cars run in fourth to get to a 1:1 ratio like a Dynojet machine, but given the 3:07 rear gears plus tall 19" tires equal a top end close to 150 mph in 4th, and that his dyno can correct for the ratio, we ran it in third.
I was going to come back and clarify the equipment so thanks for asking. First, I have the stock air filter elements in place right now. Perhaps gauze would have got me the ten more hp everyone claims. The exhaust is a full Belanger with headers, stock cats modified to have 3" inlets and outlets, and two 18" Magnaflow mufflers on each side (one in each sill and one out back). I would think no cats would have been ten more hp easy. Maybe 20.
Normally Rich has cars run in fourth to get to a 1:1 ratio like a Dynojet machine, but given the 3:07 rear gears plus tall 19" tires equal a top end close to 150 mph in 4th, and that his dyno can correct for the ratio, we ran it in third.
