[Terry335]

Originally Posted by hotrod182

Also, for those of you who didn't see my previous post on the GTech, it is a very well designed piece of test equipment. I took mine apart to inspect it. It has some very sophisticated circuitry. Definitely not a crudely designed unit.

Hehe it looks like it has a faster processor than the Interceptor or Xede...

At higher HP levels the factory air box is a restriction, check out this chart. The difference between red and dark blue is the air lid being removed.

http://www.bmwjuice.com/jbdyno_more.jpg

[hotrod182]

I had my flat tire warning come on this morning and found a screw in my RR tire. Thank goodness for the TPM system. Even more shocking though is my 4 month old General Exclaims with 380 Treadwear rating: With only 3200 miles on them, they are almost down to the wear bars! I guess all this testing and torque takes a toll on the tires! All in the interests of science though..LOL.

[jcarlucci1]

Originally Posted by hotrod182

I had my flat tire warning come on this morning and found a screw in my RR tire. Thank goodness for the TPM system. Even more shocking though is my 4 month old General Exclaims with 380 Treadwear rating: With only 3200 miles on them, they are almost down to the wear bars! I guess all this testing and torque takes a toll on the tires! All in the interests of science though..LOL.

Wow..ive got 6k miles on mine and they still look like brand new..

[Driver72]

Originally Posted by eldy

$pon$or$hips!

You offering?

[Dan335i]

I believe the only way of truely seeing if there is a hp or trq. increase is to drive the car with a laptop hooked up in the car. Its real world driving and not on a dyno with artificial wind speeds and such.When some tuners were tuning my friends Evo,s,they tuned the car while driving it on the road. Your going to get the most accurate readings and a better tune that way.I dont know if it can be done with the 335,s that way.I,m coming from two modded Evo,s before i bought my 07 335i coupe,6MT,spt pack. The Evo as you all know are MAF sensored cars,and the 335,s are MAP sensored.That being i really dont know if they can be tuned the same way.

[Evo8MRto335I]

Regardless of the outcome, we should still give him credit for taking his time and iniciative to do all the testing on his own. This is not the first time he has done independent testing about this filter.

If someone has any critizism to make please don't post it here. Thanks for the post Hotrod

[SCCAForums.com]

Please, I'm sorry... but those of you that claim Quarter Mile times, 0-60, 60foot, and HP numbers off the GTech... should spend 1/8th the time and actually go to a dyno. Then the Drag strip... Those things are pieces of CRAP... to verify that... go take it to the DRAG STRIP... and make 3 passes... with your GTECH hooked up... and then you'll see the differance.

As for the K&N Testing... I did it (the way I think was Best)... My car had 600 Miles on it... (read Brand New OEM Filter)... I removed the filter... and put in the K&N for the drive to the dyno (read time to learn)... dyno'd the car... then removed K&N, installed new oem... redynoed the car... K&N was with about 1 or 2 HP & TQ... (On a 100% stock Car)...

Expect 4 to 7 HP & TQ as you Mod your car more and more.

Happy New Year!
Dave

PS On a side note... a Filter that REALLY Works... is the 'GREEN FILTER'... but I don't see them offering one for our cars yet... we saw 6+ RWHP on an RX8, and 7 RWHP on an LS1 Car... OVER A K&N (which was a few HP over OEM). Here is there link: http://www.greenfilterusa.com/

[AWD Addict]

Isn't there an error margin or standard deviation that should be mentioned with the GTech pro?

[edit] should have read page 2. The previous poster seems to be thinking what I am: That the GForce is an okay general measuring tool, but nowhere near precise enough to be looking for 3%-5% changes in output.

Pictures of a piece of PCB with some capacitors and transistors on it is by no means a measure of how technically capable a piece of hardware is.

[Terry335]

Originally Posted by SCCAForums.com

Please, I'm sorry... but those of you that claim Quarter Mile times, 0-60, 60foot, and HP numbers off the GTech...

He's done probably 20 runs at the track with his GTech Pro, I believe they were all within .05 and .5mph in the 1/4.

[hotrod182]

Actually I already discussed how these runs I make are often within .10mph. By being so consistant, it tells you the unit is more than likely accurate. Look at the tables and the graphs. The instrument is very sensitive to change. And the reality of the situation is there is probably more realistic measurement of performance gains of many Gtech runs in a row than comparing different dynos, different days, etc, etc. They use accelerometers in this space shuttle and missile guidance systems. If you can't understand the complexity of these LSI circuits, than don't make belittling comments about the device.

And in case you haven't seen my past comparisons of the track time slip with my Gtech, I will post them again: http://www.e90post.com/forums/showthread.php?t=93009

To Summarize:


Run #1 Gtech/Track Slip. 13.384 @ 106.33 vs 13.359 @ 106.03 mph Difference: Gtech reads .025 secs slower, and within .30mph
Run#2 Gtech/Track Slip. 13.192 @ 106.38 vs 13.141 @ 106.40 mph. Difference: Gtech reads .051 secs slower, and .02mph slower.
Run#3 Gtech/Track Slip. 13.228 @ 106.66 vs 13.216 @ 106.69 mph. Difference: Gtech reads .012 secs slower, and .03mph slower.
Run#4 Gtech/Track Slip 13.286 @ 106.28 vs 13.274 @ 106.36 mph. Difference: Gtech reads .012 secs slower, and .08mph slower.

Are you kidding me? Do you know how close these times are? On average, within .025 seconds, and .11 mph.!
Do you know how slow .10 mph is? Really, try and walk that slow and get a device to measure it. Although they can never be "official", I can definitely get more info with my Gtech testing gains from mods, etc, than waiting all day at the track to make 5 runs. In fact, next time, I will just make some runs somewhere outside of the track, and if they suck, Im saving my $50 and driving back home, LOL.

Also, for you Gtech owners. It is imperative that you know how to operate them properly. The unit must be mounted as close to perfectly perpendicular to the axial line of the car. Level it as best possible so the arrows are not dominantly pointing in any one direction more than .02g. You MUST make a preliminary run to 30, 40, 60mph, or whatever it takes to get a run reading recorded. This is how the unit sets its baseline calibration of your mounting position. Preferably do it on the same spot you are testing on. Always start at the same place. Remember, if a run is way out of line, and doesn't make sense, you probably shouldn't count it. You can see all my runs are within .3mph or so here. Maybe its because of the diffence in speed measuring methods, I have found the 1/8 mile times/mph on the Gtech to be inaccurate.(Optimistic). On the other hand, I have found that the Gtech 60' times are usually conservative, measuring .03-.05 seconds slow.

Excessive wheel spin, axle hop, or vehicle pitch will adversely affect the accuracy. So much harder to get accurate readings with manual transmission launches.

[hotrod182]

Originally Posted by SCCAForums.com

Please, I'm sorry... but those of you that claim Quarter Mile times, 0-60, 60foot, and HP numbers off the GTech... should spend 1/8th the time and actually go to a dyno. Then the Drag strip... Those things are pieces of CRAP... to verify that... go take it to the DRAG STRIP... and make 3 passes... with your GTECH hooked up... and then you'll see the differance.

As for the K&N Testing... I did it (the way I think was Best)... My car had 600 Miles on it... (read Brand New OEM Filter)... I removed the filter... and put in the K&N for the drive to the dyno (read time to learn)... dyno'd the car... then removed K&N, installed new oem... redynoed the car... K&N was with about 1 or 2 HP & TQ... (On a 100% stock Car)...

Expect 4 to 7 HP & TQ as you Mod your car more and more.

Happy New Year!
Dave

PS On a side note... a Filter that REALLY Works... is the 'GREEN FILTER'... but I don't see them offering one for our cars yet... we saw 6+ RWHP on an RX8, and 7 RWHP on an LS1 Car... OVER A K&N (which was a few HP over OEM). Here is there link: http://www.greenfilterusa.com/

So my Gtech runs on average were within .025 seconds, and .11mph of my drag strip time slip. And my Gtech is a "Piece Of Crap"??? Maybe you just can't understand the technology that goes into these things, or simply don't know how to use one properly. Go ahead and check out my link to the post. You can see the time slip and Gtech Graph for yourself. I guess your next excuse will be that I made up and photoshopped these time slips and Gtech Graphs. I also think that a 5-7hp gain would be measurable as around a .50mph increase. The Gtech consistantly can pick up the speed gain of just losing the weight of a few gallons of gas. And you think it wouldn't pick up a 6hp difference? I would be willing to bet money that if I made 3 runs with +5hp, and 3 runs without it, I could tell you which group of runs had the extra 5 hp. It would show up immediately. Well, go back to your generalizing and useless critiques. You see, I spent money on the K&N, and I "wanted" to see the improvements. Heck, I want to buy things that make my car faster. I am sharing my experiences, and I have shared the accuracy of my Gtech. Maybe its just that you don't have enough experience testing the 335i. Can you explain to me how some people don't see any Dyno HP gains running with the air box lid off, or the filter out? Perhaps the factory air filter element really isn't the big restriction on our particular cars as some people think.

[sambonator]

GTech Pro RR FTW!

http://www.caranddriver.com/features...ork-page6.html

[Terry335]

Originally Posted by sambonator

GTech Pro RR FTW!

http://www.caranddriver.com/features...ork-page6.html

Hey Sam, get that catback installed yet?

[hotrod182]

Yet another dyno test showing small gains with no filter at all. And the OP stating its not worth the extra $$ on an aftermarket air filter.

http://www.e90post.com/forums/showthread.php?t=104677

So by looking at this post, he got about +2.5hp by totally removing the stock air filter. So do you really think you are going to gain even more horsepower by installing the K&N compared to no filter at all???

There has been quite a bit of tests substantiating my opinion. You can make what you want out of these results, but its pretty convincing to me..

[Driver72]

Originally Posted by hotrod182

Yet another dyno test showing small gains with no filter at all. And the OP stating its not worth the extra $$ on an aftermarket air filter.

http://www.e90post.com/forums/showthread.php?t=104677

So by looking at this post, he got about +2.5hp by totally removing the stock air filter. So do you really think you are going to gain even more horsepower by installing the K&N compared to no filter at all???

There has been quite a bit of tests substantiating my opinion. You can make what you want out of these results, but its pretty convincing to me..

But when we dynoed Terry's car we removed the air lid and it gained 10 rwhp??

So there are plenty of conflicting dyno results.

Plus, Warren, keep in mind, on MOST dynos, there is not a sufficient fan blowing on the front of the car that would replicate the amount of air that would be being forced into the air box with having 60-130 mph winds hitting the front of the car like you'd get doing a full throttle redline run in 4th gear on the road.

With just little 20-25 mph winds, taking the air filter out won't change much as the air filter is NOT restricting enough air to make a difference in that little air speeds.

Have a fan blowing 100 mph winds to the front of the car and remove the air filter, and you'd see a whole different story.

There is no doubt, a less restrictive air filter will get you more power, ESPECIALLY when on the road AS SPEEDS climb.

[Terry335]

I think the lid setup is the main issue, more so than the filter itself.

[hotrod182]

Originally Posted by Driver72

But when we dynoed Terry's car we removed the air lid and it gained 10 rwhp??

So there are plenty of conflicting dyno results.

Plus, Warren, keep in mind, on MOST dynos, there is not a sufficient fan blowing on the front of the car that would replicate the amount of air that would be being forced into the air box with having 60-130 mph winds hitting the front of the car like you'd get doing a full throttle redline run in 4th gear on the road.

With just little 20-25 mph winds, taking the air filter out won't change much as the air filter is NOT restricting enough air to make a difference in that little air speeds.

Have a fan blowing 100 mph winds to the front of the car and remove the air filter, and you'd see a whole different story.

There is no doubt, a less restrictive air filter will get you more power, ESPECIALLY when on the road AS SPEEDS climb.

Im thinking that the faster you go, the filter restriction may affect your horsepower even LESS. The engine will require a certain amount of CFM at at specific RPM to an extent (of course load/temp/boost/etc all come into play here.) But the point is, if you have slightly positive pressure coming into the airbox, it will help to OVERCOME the restriction that is present from the air filter element. To put things into further perspective. Let say you start pressurizing the airbox with a huge air compressor. The engine will only take a certain amount of air, (at a certain amount of boost), so there is a point where air filter restriction is not a factor if you have enough positive pressure feeding it. So I am thinking that improved air filter flow would give the most benefit (if any), in stationary conditions. Of course at ultra high flow applications, a filter restriction becomes more of an issue. However, I still would like to see some scientific flow data comparing the stock filter and the K&N. I wish I could find the BMW literature that I read showing how much intense engineering goes into their factory pleated air filters.

[SCCAForums.com]

First of all... read my sig... I race... I don't play... so please save the experience part.

2nd... it looks like your Gtech is consistently + or - .05... do you realize 10HP... 1 tenth of a second? So... in this case... the best case scenario for the K&N is going to be about 5 to 7HP (best case)... and that would be .05 in the quarter... exactly what your instrument (???) is off... so one run... you instrument could be closer to the time... and then K&N be off... then the Stock filter etc...

As for the tests pulling lids I've already shared my opinion on this... and I confirmed it... if you want to 'Believe' you are getting more HP for your filter, cold air kit etc... anything you do (on the dyno or anywhere else) immediately after your initial (baseline) run... will be higher... if the product flows any better... just because the first few times... you are tricking the ecu causing a slightly leaner condition based on the better flow for a moment. That is why I try to run the 'best' flowing (percieved) first... and then change to the 'lesser' flowing product... this way... your car wouldn't be tricked into be leaner for a moment... and should be closer to a real world test.

Enjoy your gtech! I'll stick to load testing on a dyno, or a drag strip.

Dave

PS... I posted the same data as you previously... very little gains... 1 to 2 HP & TQ... .on a 100% stock car... I'll be going back to the Dyno again with the SSTT just installed... and if I have 10 extra minutes... I'll swap the filters again... and see what we find. My consensous was this... it definitely doesn't hurt HP... and could possibly help... so I stuck with the K&N.

[hotrod182]

Originally Posted by SCCAForums.com

First of all... read my sig... I race... I don't play... so please save the experience part.

2nd... it looks like your Gtech is consistently + or - .05... do you realize 10HP... 1 tenth of a second? So... in this case... the best case scenario for the K&N is going to be about 5 to 7HP (best case)... and that would be .05 in the quarter... exactly what your instrument (???) is off... so one run... you instrument could be closer to the time... and then K&N be off... then the Stock filter etc...

As for the tests pulling lids I've already shared my opinion on this... and I confirmed it... if you want to 'Believe' you are getting more HP for your filter, cold air kit etc... anything you do (on the dyno or anywhere else) immediately after your initial (baseline) run... will be higher... if the product flows any better... just because the first few times... you are tricking the ecu causing a slightly leaner condition based on the better flow for a moment. That is why I try to run the 'best' flowing (percieved) first... and then change to the 'lesser' flowing product... this way... your car wouldn't be tricked into be leaner for a moment... and should be closer to a real world test.

Enjoy your gtech! I'll stick to load testing on a dyno, or a drag strip.

Dave

PS... I posted the same data as you previously... very little gains... 1 to 2 HP & TQ... .on a 100% stock car... I'll be going back to the Dyno again with the SSTT just installed... and if I have 10 extra minutes... I'll swap the filters again... and see what we find. My consensous was this... it definitely doesn't hurt HP... and could possibly help... so I stuck with the K&N.

That is the exact reason I tested back and forth for 15 different runs! To make sure any perceived gain wasn't just a fluke. Don't worry I will test later after some miles are put on the filter. My only question was whether or not a newly oiled K&N (fresh out of the package), might be more restrictive. And for all practical purposes, you can believe what you want, but my Gtech is more than useful and allows you to do more testing/comparisons than is feasible out here. The closest drag strip is terrible and is hours away. Dynos seem to have just as much variances. Even at the drag strips, your runs and MPH will vary by more than .05 mph, .05 seconds, so what really can be compared accurately? I would say you have a good chance to make valid comparisons when your Gtech runs are as consistant as mine. You can post your dyno results once you get them, but until then stick with your club racing and maybe someday you will make loads of $$$ off it. By the way, I used to autocross with the Porsche Club out here when they had events at the local Navy Base. Lots of fun, but it really beats up your car. I would buy a used car that has been run in the 1/4 mile any day over one that been autocrossed. Believe it or not, I beat many a Corvette and Porsche out there in my GN!

[SCCAForums.com]

Sounds good... yup... I'd buy a drag raced car any day over auto-X as well...
Once I started Club Racing... I left the Auto-X scene.

And there is no money in racing... unless you like making left hand turns only.. .or F1 Racing... other than that... you just go broke.

Fortunately for me... I have a proven track record, and don't have to use my own money to race. So while other people pay to have me drive for them I'll do it... but once it starts costing me money... I'll stick to the toys in the garage... and spend more time with the family.

Peace!
Dave

[hotrod182]

Originally Posted by Driver72

But when we dynoed Terry's car we removed the air lid and it gained 10 rwhp??

So there are plenty of conflicting dyno results.

Plus, Warren, keep in mind, on MOST dynos, there is not a sufficient fan blowing on the front of the car that would replicate the amount of air that would be being forced into the air box with having 60-130 mph winds hitting the front of the car like you'd get doing a full throttle redline run in 4th gear on the road.

With just little 20-25 mph winds, taking the air filter out won't change much as the air filter is NOT restricting enough air to make a difference in that little air speeds.

Have a fan blowing 100 mph winds to the front of the car and remove the air filter, and you'd see a whole different story.

There is no doubt, a less restrictive air filter will get you more power, ESPECIALLY when on the road AS SPEEDS climb.

Next time you dyno your car more than once, try and put the stock air filter back in for the 2nd run. Watch the dyno results go up! Just kidding, LOL. Seriously, when I first saw the increase in power, I was ecstatic. But after several groups of runs, I saw that it wasn't the case.

[sambonator]

Originally Posted by Terry335

Hey Sam, get that catback installed yet?

I plan to install it after "service." I will have it on before Fontana