t3/t4 Garrett advice

[tkoforpresident]

Questions:

Is it a MUST that I tune with a wideband?

Do I have to switch to a 3 bar MAP sensor?



Interesting notes from Corky Bell's Maximum Boost Chapter 1:

- A turbo can double the power without doubling the load.
- Turbo's do not increase fuel economy while not under boost.
- Boost threshold is the rpm in which the turbo has enough exhaust gasses to create boost.


Now, more questions about tuning.

I still don't know if I have to use a wideband and 3 bar map sensor to tune with my obd-1 setup but I was kind of thinking to myself about how you can tune for boost by using the "boost threshhold" By knowing the boost threshold (let's pretend 1600 rpm) you can setup the VE tables in a manner that starts dumping fuel from 1600 and up. Now this is a crude depiction but i'm sure it's not too far off.

Also, I found a deal on 6 42# lucas injectors (brand new) and a Walhbro 255 pump (also brand new) for around 300$

Should I bite?

[Joseph Upson]

Questions:
Is it a MUST that I tune with a wideband?

Do I have to switch to a 3 bar MAP sensor?

Interesting notes from Corky Bell's Maximum Boost Chapter 1:

- A turbo can double the power without doubling the load.
- Turbo's do not increase fuel economy while not under boost.
- Boost threshold is the rpm in which the turbo has enough exhaust gasses to create boost.

Now, more questions about tuning.

I still don't know if I have to use a wideband and 3 bar map sensor to tune with my obd-1 setup but I was kind of thinking to myself about how you can tune for boost by using the "boost threshhold" By knowing the boost threshold (let's pretend 1600 rpm) you can setup the VE tables in a manner that starts dumping fuel from 1600 and up. Now this is a crude depiction but i'm sure it's not too far off.

Also, I found a deal on 6 42# lucas injectors (brand new) and a Walhbro 255 pump (also brand new) for around 300$

Should I bite?

The cylinder heads have bolts that can be unscrewed holding them on, so you don't have to blow them off the motor by trying to tune boost without a wideband O2 sensor.

Honestly it can be done to a degree, but you are asking too many of the right kind of questions to suggest you'd better not try it. Even back years ago when I was boosting engines without the ability to modify code, I had a gauge that worked off of my stock O2 sensor to give me some idea of what my AFRs were.

If you are starting with a tune that is from an entirely different engine a WBO2 is mandatory. If you change your injector size considerably a WBO2 is mandatory to help you reestablish your base pulse constant. I would purchase the necessary items to properly tune the engine first, then look into assessories. You'll always find a deal on Ebay. You should have at least a 2 Bar MAP system but ultimately the code you run will determine which one you need, so don't buy one until you decide what that will be.

You can't tune your engine using theoretical formulas alone unless you have some seriously exact data regarding the fueling efficiency of your engine liking to what the manufacturer would have and that would only get you close.

[tkoforpresident]

Allright, then let's figure out for my current setup what will be best.

I wish someone would just tell me what to do, rather than my asking a bunch of dumb questions to get to the same conclusion.

I will buy a wideband because I don't want to half ass this.

I'm running $a1 right now. Which code mask should I use? Isn't there a turbo based mask out there?

Do i need different sensors based off of the answer to the above question?

I'm going to buy 42# injectors and a walhbro 255 because they will suffice my fueling needs.

I plan on running 9 psi so that I don't have to get into all of the water/meth injection stuff.


Basically, how is the best way to tune a turbo with obd-1? Someone lay it out for me

[bszopi]

You really only need a 2-bar MAP, since you won't be going over 14.7psi (1 bar = 14.7psi). As far as code base, check out code 59 : http://www.code59.org/ I have heard MANY good things about it, and I'm sure Joseph will vouch for it as well.

[ghrarhg]

I'm pretty sure $59 requires a 3 bar map.

[tkoforpresident]

What kind of map do i have right now?

[bszopi]

What kind of map do i have right now?

1-bar, ie it reads from -14.7 (vacuum) to 0psi.

[pocket-rocket]

Your car from the factory has a 1 bar. One bar reads 1 atmosphere or 14.7 lbs of pressure at sea level. Since you are adding 9 psi of boost on top of that 14.7 psi of available pressure, that is why you need a 2 or 3 bar, depending on if you go with $59 or not. Like Brad, I've heard good things about $59. Also, I would listen to Josephs opinions, he is very knowledgeable when it comes to boost. That and his comment about head bolts got me to lol. Also the quote of Robert in my sig comes to mind as well. Besides, technology has come a good way since that book was written. Why not use that to your advantage to get more out of your car than you would have 10-15 years ago?

[tkoforpresident]

I hope I don't sound like I'm disrespecting those who know infinitely more than I do about boost than I do but since I don't know the answers, I have to ask silly questions. I picked up Maximum Boost but I just started reading it. Even then, that doesn't make me an expert on turbos or even help me much for my own particular setup, especially since you mention that technology has greatly changed since that book was written.

I also have a book titled Engine Management Advanced Tuning that Bob (60dgrzbelow) sent me. It has a section on tuning for turbo applications so I will have to look into that as well.


But for now, what is involved with swapping to a 2 or 3 bar map sensor? Is it as simple as cutting/splicing the new sensor into the harness and running the same vacuum line to it? Or is it more elaborate?

Also, who knows for sure what kind of map the $59 mask runs? It sounds highly reccomended.

I should probably be talking to Ben about this too, since he will most likely have a heavy hand in the tuning side of things.

[tkoforpresident]

This is a picture of a 3 bar map sensor.


It looks almost EXACTLY like the one I have now with the single vacuum port and even the sensor connector looks the same.

Is it really then, just a matter of buying a 3 bar map sensor and replacing the old one with the new?

[pocket-rocket]

Physically it's plug and play. As far as the way it reads, the PCM has to know if it's a 1, 2 or 3 bar sensor. So yes and no. I don't believe it sounds like you are disrespecting people here. Asking questions is the only way to learn besides going out there and doing it and blowing up a few engines and learn what you did wrong.

[bszopi]

Yes, it is the same. The difference is in the programming and how the ECM converts the voltage output to an actual PSI reading.

[tkoforpresident]

The difference is in the programming and how the ECM converts the voltage output to an actual PSI reading.

Which I'm guessing is what a mask like $59 will do by default?

[bszopi]

Yes.

[Joseph Upson]

I hope I don't sound like I'm disrespecting those who know infinitely more than I do about boost than I do but since I don't know the answers, I have to ask silly questions. I picked up Maximum Boost but I just started reading it. Even then, that doesn't make me an expert on turbos or even help me much for my own particular setup, especially since you mention that technology has greatly changed since that book was written.

I also have a book titled Engine Management Advanced Tuning that Bob (60dgrzbelow) sent me. It has a section on tuning for turbo applications so I will have to look into that as well.

But for now, what is involved with swapping to a 2 or 3 bar map sensor? Is it as simple as cutting/splicing the new sensor into the harness and running the same vacuum line to it? Or is it more elaborate?

Also, who knows for sure what kind of map the $59 mask runs? It sounds highly reccomended.

I should probably be talking to Ben about this too, since he will most likely have a heavy hand in the tuning side of things.

If you start with a 730 ecm wired for the $A1 mask you've killed 3 birds with one stone, you will be able to switch between all three masks, $A1, 8F Turbo Grand Prix and $59 with a simple MAP sensor change, 1, 2 and 3 bar respectively. I can't say enough about code59 at this point, the cell follower that highlights the area of the table being viewed the engine is operating in is a very big help, especially when tracking down detonation in the spark table. Autotune is another big help in tuning 59 along with the starter bins that help by establishing a baseline for you. You'll need a tune for DIS ignition if that's what you plan to use as it primarily supporst distributor.

When I started my first turbo project I didn't ask for anything except the parts I new I would need. I purchased the two turbocharging books I could find one of which was Maximum boost and I went through them repeatedly, kind of like going to a near empty refrigerator looking for something to eat knowing you're not going to find anything new because you didn't put anything in it since the first time you looked in it that day, but maybe you missed something.

I say that to stress the importance of searching and reading up on the subject, the code59 site has a very friendly powerpoint how to, two of them as a matter of fact to help get you started among other things. Asking if it requires a 3 bar MAP sensor suggests you did not go to the site and investigate after being made aware of the code. You need an organized knowledge base or source in order to be successful at this.

How do I know, my first project was a twin turbocharged TPI IROC Z28 and I blew that freshly built motor up in two turns and less than a half mile from my driveway by thinking I'd be able to throttle it with the wastegates disconnected. The turbos spooled up quick enough and high enough to prove me wrong. It's a terrible thing to have your front end lift high and fall over while your foot is still holding the gas pedal down. Then there's that smoke that just won't go away.

There are several turbo threads related to both 8F TGP and code59 between this forum, V6Z24 and code59 that you should look at. I used related formulas and ideas picked up from reading through them to help plan and I still learn new things from doing this today. Yesterday I learned that Autotune for code59 still uses the data from the sensors when your engine stalls in the middle of a datalog and you don't want that. It's not in the powerpoint but was mentioned during a discussion about a tuning issue.

You have to read and plan, as there is so much that will be missed by posting an occasional question. It's just entirely too much to try and put in a thread.