How do you measure WOT performance while street tuning?
08-31-2010, 05:11 AM
#21
That is true Ed, not everyone has access to dynos all the time is probably the biggest issue. It sure would be nice if there was an accurate, repeatable way to measure improvements.
Why would a long flat road with the trans locked in say 3rd gear (you could even lock the converter) with the VCM controls not be similar to playing on a non-load bearing dyno? I no you have more control on the dyno, safer, etc. but if this was your only alternative, why couldn't it work. This is for my curiosity more than anything, not looking to debate or argue.
Why would a long flat road with the trans locked in say 3rd gear (you could even lock the converter) with the VCM controls not be similar to playing on a non-load bearing dyno? I no you have more control on the dyno, safer, etc. but if this was your only alternative, why couldn't it work. This is for my curiosity more than anything, not looking to debate or argue.
Last edited by 69LT1Bird; 08-31-2010 at 05:33 AM.
09-01-2010, 03:30 PM
#22
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It might be just me but 28deg of timing and a A/F ratio of 12.8 WOT will get me to where I want to be. Dynos will give different results. 10 or 20 horsepower are not worth the money to me. Also the A/F ratio set on a dyno will change on the street. You have to tune again to get it right, so I am not sure of the gain for real. Dynos are for bragging. If you want to tune a engine put it on a engine dyno. Chassis dynos can check that every thing is OK, more or less. It will also let people say "my car has 1000 HP".
09-01-2010, 05:03 PM
#23
It might be just me but 28deg of timing and a A/F ratio of 12.8 WOT will get me to where I want to be. Dynos will give different results. 10 or 20 horsepower are not worth the money to me. Also the A/F ratio set on a dyno will change on the street. You have to tune again to get it right, so I am not sure of the gain for real. Dynos are for bragging. If you want to tune a engine put it on a engine dyno. Chassis dynos can check that every thing is OK, more or less. It will also let people say "my car has 1000 HP".
09-03-2010, 04:42 PM
#24
"The Tuning School - Advanced Course" talks about using the delivered torque as CTD described. I played with it last week and it was pretty interesting. I setup a histogram (go to my web site and download it Engine Delivered Torque.hst) and logged like they described, 1000 rpms for 10 seconds, 1500 for 10, etc, up to 4000 rpms at first and later up to WOT.
They have you do timing changes, no fueling. This is all done after you tuned the MAF and VE tables so the only change is timing.
I did this 3 times, all cells logged within a couple lb ft of torque. I made a timing adjustment to small ranges at a time and relogged, if the torque increased I went up again if it went down I took away timing. I have a section in the mid-range that I added 4 degrees in total and I showed a 10 lb ft gain. Around my peak torque, 4800 or so, I add two degrees and showed a 20 lb ft increase.
It may not be perfect or be a dyno, I call it a poor mans dyno, but it looks like if done correctly it can show you if you are going in the right direction.
Do not believe the numbers (they seem high) but just look for increases or decreases in delivered torque.
They have you do timing changes, no fueling. This is all done after you tuned the MAF and VE tables so the only change is timing.
I did this 3 times, all cells logged within a couple lb ft of torque. I made a timing adjustment to small ranges at a time and relogged, if the torque increased I went up again if it went down I took away timing. I have a section in the mid-range that I added 4 degrees in total and I showed a 10 lb ft gain. Around my peak torque, 4800 or so, I add two degrees and showed a 20 lb ft increase.
It may not be perfect or be a dyno, I call it a poor mans dyno, but it looks like if done correctly it can show you if you are going in the right direction.
Do not believe the numbers (they seem high) but just look for increases or decreases in delivered torque.
It was similiar to the same way you hold your RPMs when tuning your MAF and VEs
Last edited by Phil'sC5vette; 09-03-2010 at 05:46 PM.
09-03-2010, 10:46 PM
#27
It might be just me but 28deg of timing and a A/F ratio of 12.8 WOT will get me to where I want to be. Dynos will give different results. 10 or 20 horsepower are not worth the money to me. Also the A/F ratio set on a dyno will change on the street. You have to tune again to get it right, so I am not sure of the gain for real. Dynos are for bragging. If you want to tune a engine put it on a engine dyno. Chassis dynos can check that every thing is OK, more or less. It will also let people say "my car has 1000 HP".
AFR heads respond very well to 28* timing & more, I was a bit nervous about 12.8 so I always targeted 12.6....litlle bigger window.
I've always found my street tunes almost spot on with a properly calibrated load bearing dyno or maybe I should say that other way around.
After my last dyno session with C5 I went to work on the street tune with a dip in the Torque delivered PID, it was somewhere in the 3400 rpm area. Noticeably & measurable improvement.
This past weekend I spent a lot of time with my C6 on the dyno. We ended up with TR6 plugs, final timing around 17* & best power @ 12.0 AFR. Substantial torque gains, good power gains & a much smoother power curve. I'm not sure I would have had the same success road tuning or certainly not near as quick.
The point is all of these things are tools to help get the job done, non of them are the best or in the case Torque Delivered very accurate. What Torque Delivered helps us do is measure if we are improving are not.
Another sanity check.
09-04-2010, 07:58 AM
#28
I just reviewed my HPT logs & dyno runs from last weekends dyno time with my C6.
You can see the improvement in Torque delivered following the RW Torque on the dyno.
I would have to refresh my pic posting procedure, I could post those screen shots if of interest.
You can see the improvement in Torque delivered following the RW Torque on the dyno.
I would have to refresh my pic posting procedure, I could post those screen shots if of interest.
09-04-2010, 10:09 AM
#30
I will post the dyno run latter.
First shot is how much timing I removed from the stock timing map, some KR was still present so I was going to remove additional timing.
Second shot is the first dyno run with TR6 plugs installed. No KR!
Third shot is the stock timing map restored with the TR6 plugs. Some KR returned, not near as much as I removed from the first shot.
Dyno runs I will post latter will verify the Torque Delivered change.
09-04-2010, 12:16 PM
#33
The timing change column how much I added or removed before each run.
This is the highest data I plotted. This was with 2 degrees added to the timing table from 4000-5600 RPMs.
run Labels 4400 4800 5200 5600
1st g cyl 0.92 428 424 424 430
2nd g cyl 0.92 413 430 433 442
This is the highest data I plotted. This was with 2 degrees added to the timing table from 4000-5600 RPMs.
run Labels 4400 4800 5200 5600
1st g cyl 0.92 428 424 424 430
2nd g cyl 0.92 413 430 433 442
Last edited by 69LT1Bird; 09-04-2010 at 12:52 PM.
09-04-2010, 12:38 PM
#35
Not is these logs, this was 1500 up to 3500 rpms. I was doing it in small increments from the bottom RPMs up. I have not had time to do consistent WOT runs but I am going to try this weekend.
I was just trying to show that you can show improvements or loses pretty easily even at low engine speeds.
The chart shows delivered engine torque.
I was just trying to show that you can show improvements or loses pretty easily even at low engine speeds.
The chart shows delivered engine torque.
09-04-2010, 01:06 PM
#36
So this is a steady state cruise. You can do WOT just in that window as well.
In my HPT log you can see that dip @ about 4200rpm, when I first started working on the dip I only ran to 5k rpm during the WOT runs.
One thing that I've never done is compared the injector timing between runs, in your case I would expect a small change the may reflect improved fuel mileage.
I have trouble keeping my **** running long enough to ever worry about mileage.
In my HPT log you can see that dip @ about 4200rpm, when I first started working on the dip I only ran to 5k rpm during the WOT runs.
One thing that I've never done is compared the injector timing between runs, in your case I would expect a small change the may reflect improved fuel mileage.
I have trouble keeping my **** running long enough to ever worry about mileage.
09-04-2010, 01:11 PM
#37
Yes, as steady state as you can do. Nice flat, empty road, hold the pedal steady a whatever RPM you are looking to hit and then do the next higher.
This is my toy so gas mileage is not any issue or concern. I do get 14-17 in city type driving and beating on it. If I really beat the crap out of it I will drop to the 10 range. Never have tried driving it easy, that's not this car is for.
This is my toy so gas mileage is not any issue or concern. I do get 14-17 in city type driving and beating on it. If I really beat the crap out of it I will drop to the 10 range. Never have tried driving it easy, that's not this car is for.
09-05-2010, 08:10 AM
#39
I was working in a friends Jeep yesterday for a hanging idle issue, 2008 5.3L LC9. Sweet setup for the Jeeps. I got the idle fixed and logged some data, I had the engine delivered torque in the PID table by accident. I looked at it this morning and it shows 303 lb ft of torque @3900 rpms. According to factory specs, this engine has 338 lb ft at the flywheel, coincidence, maybe but a pretty good one.
The engine is completely stock except the air filter and elbow. No headers or anything. It is backed up by a manual trans. At 10-12% loss through a manual it gets it pretty close to the HP Tuners output. DTC turned off, no cats, stock injectors.
The engine is completely stock except the air filter and elbow. No headers or anything. It is backed up by a manual trans. At 10-12% loss through a manual it gets it pretty close to the HP Tuners output. DTC turned off, no cats, stock injectors.