looking for turbo tuning advice and tips

[njp98]

My custom turbo fabrication is finally complete and installed on the car and everything went very well so far, no leaks, no problems. Tomorrow my speed shop guy and I are going to start the tuning of this system. [img]smile.gif[/img]

I've installed 42lb injectors and we started the car and deep black smoke came out of the car (we knew this would happen, but we had to test if the new injectors worked because there was a wiring problem that was disgussed in one of my earier posts:
http://www.camarov6.com/ubb/ultimate...c;f=4;t=001851

Anyway, back to the tuning. As far as fuel goes, I'm running 42lb injectors, walbro 255 HP intank, Vortech S-FMU, and I have the HP Tuners Suite.

My plan is to first program the 42lb injectors so that the car will idle like stock and the injector pulse graphs will be the same graph as stock but reduced by a factor of 22/42 to account for the same length pulse of the new injectors being a little less than double the amount of the stock ones. This way the engine would behave similarly to the stock engine NA would have.

After that I'd like to use an FMU ratio of 3:1 (on a fuel:boost ratio) (something along those lines) to index the fuel with the boost preasure. I believe half the ratio is needed since the 6:1 used in many 3.8 cars with 22lbers and since I double the flow of injectors I would only need half the fuel pressure to bring it up to the same ammount of fuel per pulse.


I'm wondering a few things.

1.) Is this the correct way of doing it in the first place?
2.) If so then is my idea of using the 42lbers at the stock level and then an FMU for boost reference a good idea or is there an easier/better way?
3.) If this is the proper method then is my ratio of 3:1 correct

Thanks alot for reading this long post. I wanted to give you guys as much info as I have. If you have any questions to what other stuff I'm running check out the website in my signature. I appreciate any feedback guys.

[ September 24, 2004, 02:02 PM: Message edited by: njp98 ]

[Turbo V6 Camaro]

my pulse width at idle is 2.9ms for my 57# injectors, from what i can find the stock is like 5.9ms i think.

[Turbo V6 Camaro]

oh yeah with that pump and those injectors i would leave the FMU out for now, if you really need the fuel while your tunning the add the FMU, FMU makes tunning a little harder.

aim for 11.5:1 on the wideband

ajust your a/f raito and get it on tap then get you down,

i know it expansive but i would look into getting a MSD DIS-4 and the Multi channle boost timing master for the DIS-4, the boost timing master will retar your timing for every 1/2 pound of boost at the pull you set, so say you don' get any KR at 5 PSI but at 6psi you get 1* you tell the BTM to pull 1* when you get to 6 PSI.

i like this set up because 1 the BTM retards ONLY WHAT YOU NEED FOR A GIVEN PSI and you don't have to pull more timing untill you get KR.( ex. say you pull 1 * @ 6psi and don't get any KR @7 PSI, but at 8 PSI you get 1*KR so you have it pull 1* for 8PSI, this way you are maximizing your timing/HP ), and if for some reason, say on a hot day your PCM can still pull timing if need be.

edit just seen you had a DIS-4 add this to it

http://www.msdignition.com/n2000b.htm

[ September 24, 2004, 02:36 PM: Message edited by: viper04af ]

[Wicked 3800 V6]

Gee, maybe if we had a tuning forum on this board, things would be easier. Please present your case in the website forum.

[njp98]

Isn't 11.5 too rich? Are you saying I should start with 11.5 and work my way to around 12.5 or do you mean running normally I should have 11.5 and then when the boost kicks in it should lean out? I'll look into the boost timing box, but I'd really not have to retard my timing I'd rather mess around with the tuning so I didn't have to it. It does seem like a good idea however since it could prevent some detenation.

I have a question though, why shouldn't I use the S-FMU, what kind of problems would it cause. I heard somewhere on this forum about a 1:1 boost reference. This does not seem like a good approach to tuning with boost. So far it seems like there is no way to add fuel per boost without using an FMU or tuning the injectors so it stays rich and then leans out with boost.

Thanks alot for your advice so far.

[oil pan 4]

An 11.5/1 air:fuel is where you want to be when you open up the throttle.
Ignition timing is a very important part of tuning. Yet a lot of people over look it (I whiped out my timing light last month and none of the ricers at the auto shop new what it was or did :rolleyes: )
You don't want it to lean out when the boost comes on becase more fuel lowers the combustion temps.
The 1:1 boost/FPSI reference you question is the only thing a lot of people have.
The stock fuel pressure reg in a normal camaro acts like a vaccume ref regulator. At idel you get less fuel pressure then at WOT you get about 8-10 more psi.
It acts like a fine tuner for variations in the atmospheric pressure both at idel and WOT, they do help make a nice clean idel.
Now when you take that same stock regulator and start adding boost pressure to it throught the old vaccume line you get an increse of about 1psi of fuel pressure for every 1 psi of boost.
If you didn't have that, say you run straight 25psi (25 @ idel and 25 @ WOT) of fuel pressure with no vaccume ref and add a turbo. Now you try and run 10psi, that 10psi will cancel out 10psi of your fuel pressure. When the injector opens inside the intake it will have 10psi pushing on it and that will cancel out 10psi of your 25 psi of fuel pressure. It will be like having 15 psi of fuel pressure.

[nocutt]

I will save you the headache...
While I don't know how the HP tuners software manages to control 42lb injectors...I will let you know that those injectors will support over 500hp...plenty enough for a 231ci motor...if it is want you want!!
IMO throw the FMU away, sell it, throw it at who sold it to you... :D

To be honest there is really no correct way to tune, every tuner will have a different angle. A good tip will be to run the engine rich if you plan on loading...simultaneously map a timing curve for that particular psi. Depending on how big the turbo is...you can pull timing to help spool the turbo and then add it back at the top end when load is falling off or 'plateauing'...this is just one angle, there are many more!!...you do not need an FMU or you will throw your fuel curve in the trash!!!

[kahouna23]

As I'm reading this I'm getting kinda concerned. What you're saying about not needing an FMU......that only applies to those of us who've upgraded or "ported" the injectors past the stock value....right? So, anything above 42lb. injectors along with the larger volume fuel pump....no FMU is needed? But on the other hand....if you don't install better injectors but do install a larger volume fuel pump...you will need an FMU? Am I right or am I a total retard?

[Teufel Hunden]

Originally posted by kahouna23:
As I'm reading this I'm getting kinda concerned. What you're saying about not needing an FMU......that only applies to those of us who've upgraded or "ported" the injectors past the stock value....right? So, anything above 42lb. injectors along with the larger volume fuel pump....no FMU is needed? But on the other hand....if you don't install better injectors but do install a larger volume fuel pump...you will need an FMU? Am I right or am I a total retard?

you're right. the upgraded fuel pump goes without saying, but stock injectors = FMU, bigger injectors = No FMU.

[AllTheGoodNamesAreGone]

mid to high 11's is on the money.. low low 12's are "ok" too..

going too much lower and you will probably start to get knock or have to retard the timing more then you really want to thus sacrificing power..

i would shoot for high 11's.. them mess with your timing.. and see how it goes..

[Teufel Hunden]

Originally posted by AllTheGoodNamesAreGone:
mid to high 11's is on the money.. low low 12's are "ok" too..

going too much lower and you will probably start to get knock or have to retard the timing more then you really want to thus sacrificing power..

i would shoot for high 11's.. them mess with your timing.. and see how it goes..

Drag strip times are not related to timing! How can you say that at a certain time at the drag strip is when someone will start seeing knock?! You tune a car based on the POWER LEVELS and how you want the car to behave, THEN run it at the track and see how it does and fine tune. Basing tuning on track times FIRST is one of the dumbest things i've ever heard of.

[Th3 RiCk]

Originally posted by Teufel Hunden:
</font><blockquote>quote:</font><hr />Originally posted by AllTheGoodNamesAreGone:
mid to high 11's is on the money.. low low 12's are "ok" too..

going too much lower and you will probably start to get knock or have to retard the timing more then you really want to thus sacrificing power..

i would shoot for high 11's.. them mess with your timing.. and see how it goes..

Drag strip times are not related to timing! How can you say that at a certain time at the drag strip is when someone will start seeing knock?! You tune a car based on the POWER LEVELS and how you want the car to behave, THEN run it at the track and see how it does and fine tune. Basing tuning on track times FIRST is one of the dumbest things i've ever heard of. </font>[/QUOTE]I think he's talking about air:fuel ratios.

[Teufel Hunden]

Originally posted by Th3 RiCk:
I think he's talking about air:fuel ratios.

Even if he was, it would still be equally incorrect. ANYTHING to do with timing, A/F, all that stuff is not based on track times. You don't shoot for a time then start adjusting your computer, you get your timing, A/F, and everything the way it should be, then go to the track.

[njp98]

Why does everyone say to shoot for 11:1 AF ratio? I've heard this for safety reasons, but I've not experienced any detonation up to 12 psi in my setup, don't ask me how. The HPTs recorded the KR taking out 2 degrees of timing at 5500 or so, and the other times it was advancing it like 15 to 20 degrees on average. The AFR at idle and cruising w/o boost is about 14 flat and when boosting it goes to mid to low 12 AFR. Are these numbers good and can I improve them. My speed shop guy was very happy with the performance so far. Aside from the P1514 code throwing my engine into limp mode, but thats a different story.

[Turbo V6 Camaro]

Originally posted by njp98:
Why does everyone say to shoot for 11:1 AF ratio? I've heard this for safety reasons, but I've not experienced any detonation up to 12 psi in my setup, don't ask me how. The HPTs recorded the KR taking out 2 degrees of timing at 5500 or so, and the other times it was advancing it like 15 to 20 degrees on average. The AFR at idle and cruising w/o boost is about 14 flat and when boosting it goes to mid to low 12 AFR. Are these numbers good and can I improve them. My speed shop guy was very happy with the performance so far. Aside from the P1514 code throwing my engine into limp mode, but thats a different story.

11.5 is were most FI make the most power.... 12.5 is were NA cars make the most power 14.7:1 is were your car make the least amount of pollution.