SPC2slowww said:

Hello, cant really find the answer I'm looking for so help please? Haha
I have a 93gsx it has 272s, 1000cc injectors, fmic, 3in exhaust and tuned on 15lbs on stock 14b turbo, i recently realized the turbo has slightly more play than id like..
My question is if i cant source a good 14b, and bought a 16g how would that affect the tune? Would i be able to run it on a couple psi lower until i can get it retuned? Thanks in advance

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Do you have a tuning software such as ceddymods (black box ecu) or dsmlinksettings ( EPROM ecu ) ? Wideband and/or safc? (Hopefully not safc if you have 1000cc injectors.) The 16g will obviously be pushing more air at compared boost levels so if you don't have the know-how to safely correct the tune you should be fine to run boost 2-3psi lower than what you normally run until you get it tuned properly.
Just my 2 cents,
-Danny

Sorry should have added that, yes wideband and its tuned on dsmlink, i am just lacking the laptop with link and knowledge of tuning haha

Well if you got it tuned at a shop they usually charge minimal rates to do a quick retune if they are reputable. If you want to save yourself a hundred dollars and learn more about your vehicle, I'm sure there's enough info on this site to turn you into a tuning guru . However, Since you don't have a laptop, installing a 16g and turning the boost down a couple notches should be okay.

You don't necessarily need a laptop to tune with link. A tablet or netbook will work as long as it has a USB port. Just another opition. If you are going to spend to have it retuned possibly, then look for one of those options instead of a laptop. 2-3 psi sounds about right for the change in flow between the 14b and 16g at 14-16 psi. Good luck.

Are you running a maf, or speed density? If you are using a maf it won't make a difference. If you go to a 16g with a larger turbine housing you'll probably run a tad leaner with a speed density setup.

Eh either way i dont have the link program/software and im on speed density

If you have the cable and chipped ecu, you can download it from ecm tuning

http://www.ecmtuning.com/downloads.php

The software is free.

^^ and to add to that...
If you have the V3 version of link you can buy a cable off of their website
http://www.ecmtuning.com/product_info.php?products_id=42

^ ITS MAGIC!!!

Don't be afraid and have at it. Sure it sounds intimidating at first but reading up on how to tune and ecmlinks website will help u tremendously. When I switched from a 14b to e316g there was no issues at all. Just keep your eye on the wide band and aim for 11:1.1

Woow thanks guys, tremendous help!

Theoretically you only needs to retune when changing things that effect the VE such as intake, exhaust, cams, porting, others. Turbos are not a VE changing part. You should not need to retune at all or lower boost. I would just swap to the 16g as long as all your mods are sized accordingly.

Mello said:

Theoretically you only needs to retune when changing things that effect the VE such as intake, exhaust, cams, porting, others. Turbos are not a VE changing part. You should not need to retune at all or lower boost. I would just swap to the 16g as long as all your mods are sized accordingly.

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If that's true, why can't you just bolt up a 20g and go or turn boost up to lower 20's on a 14b stock set up? Afr's will be off with increased air flow correct??
14b@ 22psi will flow about 405-450 CFM depending on porting and set up
E316g@ 22 psi flows 505-550+CFM
So, how would you not have to tune? I'm not following.

Mello said:

Theoretically you only needs to retune when changing things that effect the VE such as intake, exhaust, cams, porting, others. Turbos are not a VE changing part. You should not need to retune at all or lower boost. I would just swap to the 16g as long as all your mods are sized accordingly.

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Turbos do change ve. A 16g at 30psi is going to flow 40-42lbs/min, I've seen around 60lbs/min at the same boost with larger turbos.

Dstarperformance01 said:

If that's true, why can't you just bolt up a 20g and go or turn boost up to lower 20's on a 14b stock set up? Afr's will be off with increased air flow correct??
14b@ 22psi will flow about 405-450 CFM depending on porting and set up
E316g@ 22 psi flows 505-550+CFM
So, how would you not have to tune? I'm not following.

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@donniekak so, I am correct?

As long as the fuel system is capable of supplying the amount of fuel demanded a maf based system won't need afr tuning as long as you are within the range of the sensor.

Say you are running a gm maf, link, 1600cc injectors, and a 14b. Upgrading to a larger turbo shouldn't change the afrs because the air mass is actually measured.

Now with the same setup running sd you'll need to tweak the ve table to hit the commanded afrs in the table. I've found the exhaust side of the turbo to have the largest effect on ve.

Okay. If the 14b has the standard 6cm^housing and the 16g has the 7cm^ or porting job, is that enough to change anything like afr's on a non SD set up? If not is there a general rule of thumb, like if you go to X housing that's X amount bigger than X the original size?