L36 Test results: Stock intake/AF vs gutted airbox w/K&N
#21
Senior Member
Posts like a Corvette
Thread Starter
Join Date: Jan 2007
Location: San Diego, CA
Posts: 1,451
Likes: 0
Received 0 Likes
on
0 Posts
Sorry about opening a can o' worms on the LIM
I used MAF, rpm and IAT data from Scantool capture data during WOT runs. For the VE% computations, I used only data from captured points where the rpm'* were between 4000 and 4500, the TPS showed 100%, and O2 sensor 1 showed 0.920v to 0.950v. I used the formulae on this site to calculate:
http://www.installuniversity.com/ins...n_9.012000.htm
Originally Posted by Foghorn
What parameters and methods were you using to calculate VE?
Cheers,
Cheers,
http://www.installuniversity.com/ins...n_9.012000.htm
#22
Senior Member
Posts like a Corvette
Join Date: Jan 2004
Location: Montréal, QC
Posts: 1,374
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by agrazela
Sorry about opening a can o' worms on the LIM
What was your LTFT for these runs?
Interesting how GM approaches the VE for the L36 and L67 from 97 and up. The PCM VE table is 80% across all MAP/RPM combinations for the L36 but varies for the L67. You know that the PCM VE table is a multiplier value for the MAF?
Cheers,
#23
Senior Member
Certified GM nut
Join Date: Dec 2002
Location: plattsburgh NY
Posts: 2,037
Likes: 0
Received 0 Likes
on
0 Posts
Oh i know, i am not going to jump into it. I plan on doing a few more little things before this even crosses my mind. I am just saying that i have my eye on it and i am going to continue to read about it and what not. When i do my HV3, i am going to do probably do this since i will have it half way apart. I will be in contact with all of you guys about this around spring time. I want a 14 second pass before i do anymore mods. I know the car has one in it and i want to push the mods i have now to the limit before i add more. But come spring i plan on doing the HV3, the ported LIM, and having some work done to my TB, and some custom computer work. Ohhh i cant wait til spril to get back to the track lol
#24
Junior Member
Posts like a Ricer Type-R
Originally Posted by 95naSTA
When I swapped my home ported heads (summer 05) for MMS heads I polished the runners in the LIM.
#25
Senior Member
True Car Nut
Originally Posted by willwren
Polishing the runners will be nearly a negligible effect in flow improvements. It'* the port-matching where you gain the flow.
#26
Senior Member
Posts like a Corvette
Thread Starter
Join Date: Jan 2007
Location: San Diego, CA
Posts: 1,451
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Foghorn
Originally Posted by agrazela
Sorry about opening a can o' worms on the LIM
What was your LTFT for these runs?
Interesting how GM approaches the VE for the L36 and L67 from 97 and up. The PCM VE table is 80% across all MAP/RPM combinations for the L36 but varies for the L67. You know that the PCM VE table is a multiplier value for the MAF?
Cheers,
Please explain more about your comments regarding the PCM...are you saying the PCM limits the VE to 80%? :?
#27
Senior Member
Posts like a Corvette
Join Date: Jan 2004
Location: Montréal, QC
Posts: 1,374
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by agrazela
Originally Posted by Foghorn
Originally Posted by agrazela
Sorry about opening a can o' worms on the LIM
What was your LTFT for these runs?
Interesting how GM approaches the VE for the L36 and L67 from 97 and up. The PCM VE table is 80% across all MAP/RPM combinations for the L36 but varies for the L67. You know that the PCM VE table is a multiplier value for the MAF?
Cheers,
Please explain more about your comments regarding the PCM...are you saying the PCM limits the VE to 80%? :?
Still, I was drifting on a tangent about VE. You can compare changes with the methods you used, though 4% variation between runs is quite a bit, just that they may not be actual VE values.
Cheers,
#28
Senior Member
Posts like a Corvette
Thread Starter
Join Date: Jan 2007
Location: San Diego, CA
Posts: 1,451
Likes: 0
Received 0 Likes
on
0 Posts
Please, pursue the tangent regarding the PCM VE table and a multiplier for the MAF...I want to learn more about that.
(BTW, I think the variability in this data was well within expectations...if you propagate error and assume that each input is accurate to +/-1%, there would be an expected error in the VE calculation of almost +/-3%)
(BTW, I think the variability in this data was well within expectations...if you propagate error and assume that each input is accurate to +/-1%, there would be an expected error in the VE calculation of almost +/-3%)
#29
Senior Member
Posts like a Camaro
Originally Posted by agrazela
Please, pursue the tangent regarding the PCM VE table and a multiplier for the MAF...I want to learn more about that.
(BTW, I think the variability in this data was well within expectations...if you propagate error and assume that each input is accurate to +/-1%, there would be an expected error in the VE calculation of almost +/-3%)
(BTW, I think the variability in this data was well within expectations...if you propagate error and assume that each input is accurate to +/-1%, there would be an expected error in the VE calculation of almost +/-3%)
Given that, your original standard deviation for your groups were 1.58% and 1.54%, respectively.
Anyway, curious to see what comes of all of this -
#30
Senior Member
Posts like a Corvette
Thread Starter
Join Date: Jan 2007
Location: San Diego, CA
Posts: 1,451
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by mkaake
Just as a quick aside, it looks like you used Excel to figure out your standard deviation... but you need to use stdevp(), not stdev(). stdev() is only an approximation to standard deviation, whereas stdevp() is the calculated value. I think the only reason they provide both functions is for calculation time on very large data sets... but they should have made the more intuitive stdev() the real calculation, and not an approximation.