Skinny

iTrader: (11)

I don't want this to turn into a wet-vs-dry debate. I'm researching both possibilities and I currently have a couple questions about tuning for dry applications.

1. Currently the only thing on the market (that I know of) for fuel injector control, short of complete engine management like BS3, etc, is Harris Speed Works "Interface" controller. The Interface, however, requires a MAF. Is there a way to tune for it in a speed density application? I saw something mentioned about using EFI Live and the switchable tune thing to do it, but no details where mentioned.

2. In order to supply adequate fuel for the power levels I'm aiming for, I'll need significantly larger injectors than is required for N/A. What will this do for me when that much injector is NOT being used (NA)?? I'm not sure exactly what size injector I may need, but for arguement sake lets say that I need around a 80lb/h injector to supply for a 250+ shot; on motor, a 40lb injector is plenty. How do I get a 80lb injector running smoothly on a motor that requires half that?

As I said before, I'm not getting into a wet vs dry debate (I'm sure Robert's mouth is watering already). Right now I'm just looking into the tuning aspects of dry direct ports.

Thanks!

Ray@Nitrous Outlet

you need COS 5 to do this ...it allows you to access a "nitrous tune" via a ground trigger to the PCM.

I do not have much experience in dry tuning so I will leave that to the experts

Skinny

iTrader: (11)

So by activating the PCM trigger at the same time that I activate the nitrous solenoids, I can effectively use the tune via EFI live to add fuel and pull timing, correct?

Ray@Nitrous Outlet

correct.....at least in the way I understand it.

rosey

iTrader: (13)

I run COS5, but haven't screwed with any of the nitrous controls. You'll probably want it to ground the correct wire to activate the nitrous maps when you arm the system, you can set a minimum map pressure for the fueling and spark advance changes to take effect, so it won't actually add any fuel or pull timing until you go WOT with the system armed.

As far as the injectors, you won't have any problem running them at 50% duty cycle at WOT n/a, the only place you can potentially run into problems is at low pulse widths such as idling or decel. I would talk to whoever will be tuning the car about this matter, as there are quite a few variables, and I've heard of people have problems with injectors as small as 60lb/hr, but obviously people have run much bigger without issue.

Beer99C5

iTrader: (21)

There is a EFI-Live tuning shop in Jax that does COS5 stuff on a regular basis. PM me for their info (they are not a sponsor here).

Nick@HSW

iTrader: (4)

Travis,

Unfortunately you would be required to run a MAF system if using our interface. Shoot me or Matt a PM with what you're looking to do and we'll see if we can't help you out further.

Nick

Nitro Dave's Nitrous Outlet

iTrader: (25)

Idea Duty cycle on an injector is between 60 percent to 85 percent..

The problem with running to large of an injector is that the fuel attomization is poor. Basically the fuel comes out of the injector as a droplet instead of a fine mist. So you really need to find the happy medium. If the duty cycle is to low drivability and idle would be a monster to tune.
Tunning on to large of an injector would be even harder on a speed dencity application.

Now the purpose of using a directport is for the ability of induividually tunning each cylinder as well as having equal amounts of flow to each cylinder. So basically if you do not have the right set up to be able to take away or add fuel into each individual cylinder you are taking away the aspect of individual cylinder tunning..

Yes you could adjust the nitrous pill up or down but now you are flowing different amounts of power (Nitrous Flow) to each cylinder.

So In a perfect dry direct port you are going to need the correct software to individually add or take away fuel by each injector as well as finding the happy medium for the right size injector so that the car acts correctly on motor driveability.

With a wet Directport you have the ability to easily tune the fuel to each cylinder by simply changing the fuel jet as well as supplying equal amounts of Nitrous to each cylinder while still haveing the best injector size to support the motor.

How much power are you making on motor and what is the max you plan to spray?

Dave

Robert56

iTrader: (2)

First off the DP dry will not require individual cylinder tuning and one of the reasons it is so great. A per cylinder tuned DP wet hit will in fact have a greater EGT span than an untuned per cylinder dry DP, end of story. As for injectors, the only problem having big enough for a very large hit was there were none compatible with our stock PCMs (had to run an aftermarket driver box), that has been fixed now, Racetronics has 80lb'ers that work with the stock PCM. Plenty of guys are already running them, just go to the forced induction/N2O section at corvetteforum and you will see tuners doing 160lb'ers and making them work fine, knowledge is power, find someone whom can help (my write up on injector scaling may give some insight). If you don't have a tuner program already, just get the EFI Live Coss 5, but if ya have another there are other options that will work. The Direct Port Dry is the bomb for a killer street/strip set-up no doubt, smart move. Being on the cutting edge you will hear guys saying, this and that, who have never had experience with what your doing, so sometimes we have to weed through the info, but doable it surely is and it's catching on. Good luck and keep us updated as many would like to know how it goes. You can always contact me anytime if I might be able to help somehow, and/or HSW is really on top of the dry stuff also, and where i go for info when I can't figure it out.
Robert

Skinny

iTrader: (11)

Currently at 420hp at wheels and plan to spray as much as a 300 shot through 1 or 2 stages on a Vic jr manifold. Motor is forged 346 cube. As I said earlier, I'm not completely sold on a dry DP system, I'm just researching all options.

Nitro Dave's Nitrous Outlet

iTrader: (25)

How can you say that there is no need to individually tune a cylinder that may be burning differently than another cylinder. In the event someone has ported the heads or intake this will change how evenly the airflow is delivered into each cylinder. I have seen some applications that were ported that just simply flowed differently in defferent cylinders. With out the ability to tune each cylinder how would you aid the fact that that cylinder was burning leaner and not change the amount of Nitrous flow to each cylinder?

Yes in a perfect world every cylinder would flow exactly the same and you should be able to introduce the nitrous mixture to each cylinder with out having to tune but in many instances this is not the case.

As far as running a HUGE injector there is a great difference between a NA application and a boosted application..


Dave

ATVracr

iTrader: (5)

Dry direct port here..... I had a single stage wet direct port last year. Went to a FAST compuer this year and we are spraying N20 thru both sides of the nozzle, so now I have a 2 stage DRY direct port. Its working great!!

Also has 83lb injectors idles fine (speed density with 105mm TB)and has plenty of room for us to go higher on the jets.

ATVracr

iTrader: (5)

If you have a need to tune each cyl. why not just add more jet or take away some jet from each cyl. ? isnt that 1 of the benifits of having a DP?

Robert56

iTrader: (2)

look for the thread on individual cylinder tuning. there is mucho info there to state the reasons you will be fine, and actually it was a poll to find out how many street/strippers on this site were individually tuning wet or dry DP kits. IIRC, there was not any. The reason that thread was started is because the same individual came into the last DRY DIRECT PORT thread and tried the same banter. Now, I challenge anyone on the INTERNET where this person has gone into one of his favorite and chosen direct Port wet threads and started talking crap about needing individual cylinder tuning, that will prove all that needs proving. just because someone wants to **** on every DRY DIRECT PORT thread does not mean he has any actual experience. listen to those that have gone that route.

Here is the main reason that the wet DP kits need individual cylinder tuning. they are having the fuel come in one end of a supply tube and it is not an even flow to all cylinders, so they vary more than a dry that gets a much more linear fuel supply to all cylinders from the same injectors that work great day to day. this has been tested out and the dry is much closer, whether reading plugs, using EGTs or for the ultimate individual a/f reading. Now if you were NHRA bound and running a 400/500 hit then yes, time for serious advanced tuning even dry. same with boosted cars, they do no individual cylinder tuning because they also use the stock engineered injectors. don't always listen to the nonsense the INTERNET can provide.
Robert

Nitro Dave's Nitrous Outlet

iTrader: (25)

Wayne,
I here you there and I am in no way saying that it can not be done that way. Im just saying at the point of changing the nitrous pill you have created un even flow to each cylinder. Changed the HP amount.. Is it really going to make a huge difference. Probley not if its a small change but my arguement is that that cant be the best option... Not saying its not an option...

Im just saying with a dry direct port like with an after market system you can adjust the fuel flow through the injector to each cylinder. With this method you actually have full tunability to each cylinder with out changing the flow characstics of the nitrous...

With out this ability the wet Directport gives you more accurate tunability..

Dave

Nitro Dave's Nitrous Outlet

iTrader: (25)

Robert.. Why do you have to turn everything into a damn war... It sure was nice when you were off crying in the corner and not here on LS1tech starting ****.. Ease up alittle. I do not have time for the argueing... Just because my opion does not back your opions does not mean you need to slam me every chance you get.
Have a good day.
Dave
Dave

ATVracr

iTrader: (5)

I agree and thats why I went with the FAST computer for my Dry DP. Its crazy what you can do with it!!!

Nick@HSW

iTrader: (4)

Travis, got your PM. Shooting you over a reply now.

Nick

Nitro Dave's Nitrous Outlet

iTrader: (25)

Ok so we are on the same page then..

Robert56

iTrader: (2)

that's cool and nothing wrong with FAST. the thing is, not all will be piloting 8 second cars. many of us will just be doing street/strip cars, and us Vette guys are far and few that can get into the 9's at any power level. I guess the point is, a FAST is not mandatory with a DP Dry. From what i have seen, and others reporting running the Dry DP, that a/f ratio spread between cylinders is in fact quite low. Many times, they are as close, or closer than a tuned per cylinder wet DP hit, right from the get go. My flow numbers per cylinder are remarkably close with standard jetting, and that is really great and another big plus for dry. they vary per cylinder only .001. then getting the injectors checked/flowed, we can put any positive injectors into the holes that are susceptible to being slightly lean with the LSX style intake. this brings up another point, the lean cylinders seem to go away with a single plain, or at least partly compared to the GM style intake and it's issues in the flow dept. the nature of the wet DP causes the need for this type of tuning, and this does not seem to carry over to dry. maybe you could tell us how much variance you had, and what you did to get it inline.
Robert