Tune after Header install? How soon?
Melting Slicks
Joined: Aug 2002
Posts: 2,737
Likes: 2
From: California USA
Gee, then I guess your cars don't run when the outside temp is -10*, or 110*, HUH? Not saying the car won't pick up a horsepower or two, but the CAI,..... BS. All it does is collect COLD AIR!!! What's the difference in driving in the winter, when the intake supply is much colder and denser, and driving in the summer heat? The car's PCM compensates. Leaner because of headers. Will your car not run 1200' above sea level? The pcm in these cars is designed to run the engine in a wide parameter of conditions. If you wish to throw away $600 for a dyno tune on a car with minor mods, then knock yourself out. 
ALSO, IAT and ECT temps have fuel multipliers. The VOLUME of air is multiplied by the PE VS RPM table, therefore temp is not compensated for.
Have you ever datalogged your engine??
Former Vendor
Joined: Nov 2005
Posts: 11,792
Likes: 255
From: Ossining New York
St. Jude Donor '07-'08-'09-'10-'12-'13-'14
Yes, I agree.....
You are not correct. I have datalogged cars with just a Vararam and other air filters. The PCM IS calibrated for WOT conditions with the given air filter. When you add another, the engine WILL run LEAN on top end. Fuel trims WILL NOT correct this.
ALSO, IAT and ECT temps have fuel multipliers. The VOLUME of air is multiplied by the PE VS RPM table, therefore temp is not compensated for.
Have you ever datalogged your engine??
ALSO, IAT and ECT temps have fuel multipliers. The VOLUME of air is multiplied by the PE VS RPM table, therefore temp is not compensated for.
Have you ever datalogged your engine??
Yes, I agree.... And to explain (and throw a plug for the BEST intake on the market....) The VARARAM! is different from most others as not only does it collect VOLUMES of COLD air, but it ACCELERATES the air pas the mass air meter for fantastic performance.
Part of the reason for my backup here is that the PCM does detect VOLUME as well as TEMPERATURE and is programmed to compensate for each.....That's EXACTLY why products like the VARARAM! work so well.....
You feed the engine MORE, COLDER Air....the PCM sees it coming by way of the MAF (which contains the IAT sensor) and Wha-lah!...MORE POWER.
STAY TUNED!
Chuck CoW
Melting Slicks
Joined: Aug 2002
Posts: 2,737
Likes: 2
From: California USA
Right on Chuck.
For the poste, I believe what I was trying to say was adding aftermarket devices in front of the MAF skews the MAF data pretty bad. GM obvisouly spent alot of time programming the pcm w/the particular characteristics of the stock airbox and maf sensor.
By datalog, I was trying to make the point that this tune will need to be reprogrammed if the airflow is different in any way than a stock airbox. IN EVERY CASE I KNOW OF, it is. According to some of Jim Hall's writings, he has worked on this with Killer Bee??
For the record, when I originally installed the Vararam, I LOST HP at the track and seat of the pants. This was because the device was working so well. I was getting lean codes and the car just felt horrible to drive. After I "fired" the Vararam and bought the HallTEch product, I realized what the problem was and tuned around it. The HallTech product seemed to make more car more responsive for whatever reason.
For the poste, I believe what I was trying to say was adding aftermarket devices in front of the MAF skews the MAF data pretty bad. GM obvisouly spent alot of time programming the pcm w/the particular characteristics of the stock airbox and maf sensor.
By datalog, I was trying to make the point that this tune will need to be reprogrammed if the airflow is different in any way than a stock airbox. IN EVERY CASE I KNOW OF, it is. According to some of Jim Hall's writings, he has worked on this with Killer Bee??
For the record, when I originally installed the Vararam, I LOST HP at the track and seat of the pants. This was because the device was working so well. I was getting lean codes and the car just felt horrible to drive. After I "fired" the Vararam and bought the HallTEch product, I realized what the problem was and tuned around it. The HallTech product seemed to make more car more responsive for whatever reason.
Thread Starter
Instructor
Joined: Mar 2007
Posts: 223
Likes: 0
From: Casper WY
So you can do your mods and use the hp tuner hooked to your car to log the parameters so a tuner can do a more accurate tune? I really wish I lived closer to a "good" tuner and shop so it wasn't such a big deal.
Former Vendor
Joined: Nov 2005
Posts: 11,792
Likes: 255
From: Ossining New York
St. Jude Donor '07-'08-'09-'10-'12-'13-'14
A agree with you.....
Yes, it is VERY IMPORTANT to tune a vehicle with an after market intake....Although the VARARAM! works great by itself...., it should really be tuned....
As I always say...If you are using a TRUE Cold/RAM Air intake, you MUST tune it on the street.
A vehicle running 100mph on the dyno vs. 100mph on the street or track is totally different when it comes to AIR FLOW!
Stay TUNED!
Chuck CoW
