SD tune and total conversion?
Thread Starter
Joined: May 2005
Posts: 550
Likes: 0
From: Valdosta, georgia
SD tune and total conversion? I've done sd tunes before but it's been awhile and never on a total conversion. I am swapping an lq4 into my 98 chevy truck. I'm using a 2001 silverado dbc harness and a 411 pcm. Now if I want to go SD on this truck I know you leave the MAF out, but do you also leave out all the O2 sensors also? I will most likely either be having somebody tune for me or buying efi live and a wideband kit. Anything else I can leave out with a sd tune?
I've done sd tunes before but it's been awhile and never on a total conversion. I am swapping an lq4 into my 98 chevy truck. I'm using a 2001 silverado dbc harness and a 411 pcm. Now if I want to go SD on this truck I know you leave the MAF out, but do you also leave out all the O2 sensors also? I will most likely either be having somebody tune for me or buying efi live and a wideband kit. Anything else I can leave out with a sd tune?
I do my own tuning is speed density using a wideband sensor. Once done, I run it that way. This is on a 2bar (boosted) setup but it works the same as naturally aspirated.
We removed tons of wires. I am using my injectors & coil wires, tps, iat, iac, crank & cam sensors, ect & auto trans wires, then 2 wires to power the pcm, some grounds & the wires for the obdII port. That's it, the rest went in the garbage.
This is for an old rat rod & doesn't need much. I haven't figured out my gauges yet & other misc wiring.
TECH Resident
Joined: Aug 2004
Posts: 875
Likes: 2
From: Portland Oregon
SD tune is no MAF. You need the front O2 sensors if you want to run in closed loop.
Open loop is OK for race cars, but it is usually pretty rich for the street. you don't need the rear O2. You can tune the software to not look for those, they have no affect on how the car runs, they verify that the catalic convertors are working.
Open loop is OK for race cars, but it is usually pretty rich for the street. you don't need the rear O2. You can tune the software to not look for those, they have no affect on how the car runs, they verify that the catalic convertors are working.
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Doc
If you have a shop that's not super busy and a good tuner then they will probably do the SD tune. But it does take time to get it right so in effect for a busy shop its not cost worthy to tie up the dyno for hours and hours, unless they are charging you by the hour, then it will be expensive for you. Back in the day when you had to erase a factory SD chip car (93's) it took app 30-40 minutes to erase the chip. We charged for a dyno tune and not by the hour. With cars lined up waiting for a tune, it took too much time and it was not cost worthy for us, so I stopped doing the 93's...
I do VE tuning on every car that isn't stock-internals, so SD tuning is actually FASTER for me than full tuning with a MAF too. Honestly, once you get comfortable with VE, it tunes very quickly (except for the guys that are convinced they can do it just fine with trims).
True, like you say you are very knowledgeable and experienced with VE tuning, That's why I quoted a good tuner could do it. If you do a lot of VE tuning like yourself, then you know pretty much what, where to set parameters...
