RacerJJ Posted April 14, 2008 Report Share Posted April 14, 2008 I want to get rid of my MAF and just run open throttle body on my truck without the intake. Has anyone done this? Tell me what I need to do if you have. I have seen a lot of camaros at the track doing this and since my SSS is a drag truck only now, this is what I want to do. I will be using HP Tuners to attempt this. Please let me know if anyone has any insight. TIA... Quote Link to comment Share on other sites More sharing options...
Hrtbeat1 Posted April 14, 2008 Report Share Posted April 14, 2008 If you disconnect the electrical connector to the MAF the PCM should revert to a SD type system. This is built into the tune in case of MAF failure. Tuning SD is a little different ... it relies more on the LTFTs and STFTs which need to be as close to zero as possible. To achieve this takes a lot of data logging and adjusting your VE tables accordingly. Quote Link to comment Share on other sites More sharing options...
04CHASE Posted April 14, 2008 Report Share Posted April 14, 2008 honestly i dont see it benefitting you , your truck is consistant , leave it . also you race in a vegas too so your altitude changes which will also cause your tune to be off slightly . imo id leave it but ill let some more experienced tuners chime in. Quote Link to comment Share on other sites More sharing options...
dozer Posted April 14, 2008 Report Share Posted April 14, 2008 (edited) If you want to run OLSD dont just unplug the MAF. Your IAT sensor is in there and IAT is used in part to figure Dynamic Cylinder Air flow since the MAF would not anymore. To turn off the MAf go to Engine Diag/Airflow/Maf Fail High and set the Hz to 0. If you want to remove the MAf from the intake you need to do a IAT sensor relocate using this sensor MSD IAT sensor. The Tan (signal) and the black (low ref ground) wires in the MAF plug harness are used for the IAT sensor. Just splice both of those to the new IAT sensor and re-tune of course. Make sure when you scan you remove all the MAF PIDs and add Dynamic Cylinder Airflow or else you will get conflicting readings as the two calc Dynamic Air Flow diffrently. Edited April 14, 2008 by dozer (see edit history) Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted April 14, 2008 Author Report Share Posted April 14, 2008 If you want to run OLSD dont just unplug the MAF your IAT sensor in in there and IAT is used to in part to figure Dynamic Cylinder Air flow since the MAF would not anymore. To turn off the MAf go to Egine Diag/Airflow/Maf Fail High and set the Hz to 0. If you want to remove the MAf from the intake you need to do a IAT sensor relocate using this sensor MSD IAT sensor. The Tan (signal) and the black (low ref ground) wires in the MAF plug harness are used for the IAT sensor. Just splice both of those to the new IAT sensor and re-tune of course. And make sure when you scan you remove all the MAF PIDs and add Dynamic Cylinder Airflow or else you will get conflicting readings for some reading as the two calc Dynamic Air Flow diffrently. Thanks for the reply? Where is the best place to relocate that sensor to? Also, what do you mean by "re-tune?" I would say that I am an amateur tuner at best so I don't understand some of the accronyms you have listed here (PIDs). Thanks for the help, I really appreciate it. Quote Link to comment Share on other sites More sharing options...
dozer Posted April 14, 2008 Report Share Posted April 14, 2008 (edited) Thanks for the reply? Where is the best place to relocate that sensor to? Also, what do you mean by "re-tune?" I would say that I am an amateur tuner at best so I don't understand some of the accronyms you have listed here (PIDs). Thanks for the help, I really appreciate it. Right now you are using the MAF for fueling. Your MAF is an air meter and when it see XX amont of air the pcm then make calc for how much fuel to ad for the air flow it is seeing. When you go SD you are removing the meter so now the PCM uses your VE table for fueling so you would have to re-tune to make sure the VE is fueling corretly. What I mean by re-tune is datalog with a wideband O2 and make changes to the VE to get your fueling inline for your needs. PIDs are the sensor you chose to monitor on your Table Disply in the scanner. You could relocate the sensor to your intake manifold. Edited April 14, 2008 by dozer (see edit history) Quote Link to comment Share on other sites More sharing options...
chpspecial Posted April 14, 2008 Report Share Posted April 14, 2008 John, your tune was set up using auto VE tuning via speed density on Arts truck, your tables are very close to his and you don't really need to go into speed density again unless you want to fine tune your truck. I haven't used HPTuners to set up a speed density tune, Just EFILive and can help you if you would like, but you will still need the throtle body to control engine rpm, at least I think so... On arts truck the fuel trims are at zero or atleast very very close to it. Quote Link to comment Share on other sites More sharing options...
Hrtbeat1 Posted April 14, 2008 Report Share Posted April 14, 2008 If you want to run OLSD dont just unplug the MAF. Your IAT sensor is in there and IAT is used in part to figure Dynamic Cylinder Air flow since the MAF would not anymore. Didn't know the IAT was part of the MAF. I erroneously took it that it was a seperate sensor. This is in part from doing the SD tune on my old '90 L98 Vette which was SD from the factory. It had a seperate IAT sensor. Thanks for the tidbit of info. I'm kinda new to tuning these LS based motors myself, but I've done a lot of tuning on L98's and LT1/4s. They all are just a bit different, but much the same. Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted April 15, 2008 Author Report Share Posted April 15, 2008 John, your tune was set up using auto VE tuning via speed density on Arts truck, your tables are very close to his and you don't really need to go into speed density again unless you want to fine tune your truck. I haven't used HPTuners to set up a speed density tune, Just EFILive and can help you if you would like, but you will still need the throtle body to control engine rpm, at least I think so... On arts truck the fuel trims are at zero or atleast very very close to it. Yes, reynaldo I would love some help. I basically want to get rid of the MAF and CAI and just run an open throttle body. I will be getting Mike's HP Tuners and laptop this week. I am free next Saturday as of right now. Quote Link to comment Share on other sites More sharing options...
misterp Posted April 15, 2008 Report Share Posted April 15, 2008 (edited) OK SD 101 - Lots of folks believe that the MAF primarily runs the fueling for the truck, this is not entirely true - fact is that (in stock form) the PCM only uses the MAF above 4000 RPM, fact is that you are already today in SD mode from the factory below 4000 RPM; this is why on some trucks (like mine) the engine runs/pulls entirely different below 4000 RPM versus 4000-RPM and above. So yes the MAF will correct for altitude and weather and yadda yadda but only above 4000-RPM because below that point it is largely ignored by the PCM. The MAF on our trucks is known to be a restriction; switching to the later 85mm MAF has seen gains of 10+ hp. Check into it on the HPTuners or EFILive forums, it's been discussed. The 100mm MAFs don't seem to be any better flowing than the 85mm ones for NA vehicles, but because they use the new-fangled sensor rather than the old Delphi 3-wire they are much more sensitive and fuel better FWIW; you can get a 100mm GM one for about $150-180. So, the way I see it is like this - the truck from the factory is already in SD mode up to 4000-RPM; question is, should I just continue to let it go SD above 4000-RPM too? Chase is right, ideally you will need to optimize your tune for the immediate weather conditions, but you should be doing that now anyways when you have serious change of altitude, I can totally see you having a LA tune and a Vegas tune. As you are not blown, there is no way you will ever outflow a 85mm MAF - my vote would be to replace your existing MAF and retune for it. Or if you have your heart set on going SD all the way (not a bad option either) then unplug the MAF and buy an IAT relocation kit (diyautotune.com $30-40) and relocate/rewire the IAT sensor into the remaining intake near the throttle body. In any case you still need to do a custom SD tune for below 4000-RPM at least, and most people that do notice drastic improvement in throttle response after doing so. If you want to disable the MAF read-up on the HPTuners or EFILive forum, you will find where to input the values to make the PCM permanently ignore the MAF (it's late and I'm lazy tonight lol). Don't forget you need a good wideband O2 sensor to do this. My $0.02. Mr. P. Edited April 15, 2008 by Mr. P. (see edit history) Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted April 15, 2008 Author Report Share Posted April 15, 2008 Is there anyway this can be done without a wide band o2? I don't have a second bung and I don't want to buy a wide band either so that is really not an option for me. Quote Link to comment Share on other sites More sharing options...
Justin Lamanna Posted April 15, 2008 Report Share Posted April 15, 2008 Is there anyway this can be done without a wide band o2? I don't have a second bung and I don't want to buy a wide band either so that is really not an option for me. since your using your truck for racing only i would invest in one. IMO though. Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted April 15, 2008 Author Report Share Posted April 15, 2008 since your using your truck for racing only i would invest in one. IMO though. I would tend to agree! Do I need to have a bung drilled in the exhaust or can I replace one of my o2's with a wide band? Better yet, is there a way to disable the o2's all together? What do they really do anyway and how does it apply to my application? Quote Link to comment Share on other sites More sharing options...
misterp Posted April 15, 2008 Report Share Posted April 15, 2008 (edited) Take out the rear O2 on the driver's side and replace with WB O2 sensor - works great! Just leave the original pigtail dangling and remember to disable the rear O2s in your tune when you get the next chance. Mr. P. Hmm nevermind I see you install a pair of pacesetters, I guess you got a custom y-pipe without rear cat bungs... Edited April 15, 2008 by Mr. P. (see edit history) Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted April 15, 2008 Author Report Share Posted April 15, 2008 Take out the rear O2 on the driver's side and replace with WB O2 sensor - works great! Mr. P. Too late! I had my rear o2's removed when I re-did my exhaust. In that case I would need to add a bung or can I use a wide band in place of the front sensor? Quote Link to comment Share on other sites More sharing options...
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