i understand the fuel pressure may vary a few pounds, but not as much as he stated. please explain to me how the interface knows how much nitrous is being used on a post maf dry kit? if you keep a constant bottle pressure with a wet kit your a/f should be very cosistant and fluctuate very little.

 

Flow rate, the computer is looking at a generated value introduced via the MAF harness/adaptor and will then factor IAT and ECt to add the necessary fuel.

 

dude, im talking if he is sparying after the maf and using the inteface to compensate for 100% of the fueling. it cannot and will not know how much nitrous is being used. it will just add how ever much fuel using the predetermined dip switch settings. do me a favor, arm your system and hit it with the bottle closed. i guratee the car will bog because of the extra fuel being added via the inteface.

 

Right, we are talking about the same issue just from different perspective. The H S W interface is modifying the MAF signal when activated and supplying a "set" fuel enrichment based on nitrous seetings used by them as their standard, same as a wet kit. I know the car will go dog rich if no nitrous is applied but the interface is used. But aren't other systems like the new NX, usng the MAF in the traditional dry manner? Which would then examine and better respond the the changes in the grams/sec readings.

 

cool, now we are on the same page. yes the new dry nx maf kit adds fuel the old school dry method (lack of better term). that is what makes that system so trick, it should vary its fuel delivery by the amount of nitrous sprayed over the maf wires. it will "know" how much nitrous is going in, which the interface cannot. the guy that designed it knows his stuff and has done alot of testing with it. however, who knows how long it will be until nx releses it let alone a 85mm version of it. until then, pass me my wet kit!!!!!

 

Nope this is pressure at the rail. Remember on certain C5's like my 2001 the regulator is built into the fuel filter which is located in the rear of the car. Depending on the quality of the filter/regulator things can change. Not to mention the pressure drop associated with the line distance from the filter to the fuel rail. You also have a delay as to when fuel is being taken by injectors and the regulator allowing more fuel when it senses a drop.

 

wrong. my 04 has the regulator and filter in the tank and the only time i get a pressure drop is when my fuel noid opens. that drop is only for a brief second and shows because the noid located next to the fuel pressure sending unit. i think there is something going with your fuel system that you need to check. depending if your car was tuned at 56 or 68 psi, you are either going rich or lean while in P.E.

 

robert, care to answer beer's/my posts?

 

I run a 100 zex wet shot kit with a custom tune no cold air intake and borla exhaust with nitto 55rs and run 11.9 all day long i think the zex kit is easy install

 

May you are not understanding this they way I am trying to say it. The pressure is not swinging that much when I am driving it. It does changes though when I do things like switch fuel brands. I can go from a tank of Chevron gas to a tank of Exxon gas and the overall fuel pressure changes. While I am driving on that tank though there is not much fluctuation for the pressure.

 

psi is psi no matter what brand of gas you are using. your regualator knows that and should keep it consistant. vairing 8 psi is not good. like i said something is up.

 

Not true, because of the design of the system with a rear return there can and will be pressure fluctuations near the fuel rail. PSI can change by gas type being used due to temperature and density. As for the regulator keeping it constant I would believe that for a nice high quality piece, but for my regulator built into a fuel filter I do not think so.

 

i guess we will just agree to disagree.

 

You also must take into account supply voltage. The pump is proportional to voltage applied.

 

very true, but it should not vary 8 psi. for instance when i turn on my boost a pump, i can see my fuel pressure gauge go up 1 psi at idle.

 

You are correct and I made my point un clear. I was trying to show that the computer can adjust the a/f ratio as needed, even n/a at part throttle; whereas, a fixed mechanical jet has not this capability on a carb car or for spray with EFI. The jets trial and error is different. The jets that are supplied are limited. You see the posts that a guy runs his 100 wet shot and it's running lean, so he then will take the fuel jets from the next level to richen it, the 150's. Then all of a sudden he is to rich. Then we must buy some more jets and it still can be a crap shot if you get the exact a/f your looking for. Now the Interface, you can adjust in 1hp increments and thus dial in exactly the a/f ratio sought. But what is really cool about this, and the wet camp should be just as excited, you can use the Interface on the wet hit for fine tuning the jets given in the kit. A win/win for both sides. The wet guys usually need to buy a timing pull device, as they can't do it like auto timing pull in HPT that I do in my write up, so why not buy the Interface for timing pulling and end up with a state of the art fueling device also, that would make wet tuning much easier. Personal preference, well maybe so; however, most do not see the value yet of the Interface even for the wet kits, so once it's understood then more may see the value and ease. Wait till the dual stage Interface comes out, and it has so many additional features, and neither is limited to the dry hits only. Just another tuning tool for all in the nitrous world.
Robert

 

Yes, but small and not a lot of time. We have it tore apart again and doing a batch of mods. That's the bitch with this hobby, always something to add or change. Currently having a bug with an adapter cable for the 90mm TB. However, I am so damn close to hitting the strip hard, I can taste it, it's that close. That is the reason we have not added my write up for my web site on my findings and what the Interface can do. I always base my stuff on real world experiance and have some more ideas on what the Interface can do and want to include all the correct info, not what i just know at this point. Hell, everyone is still learning on what the Interface can do (just realized something today). Like in my reply to Beer, most think this is a dry only tuning tool, well it's not as the a/f can be adjusted on the wet hits the same way. Man if I was running a DP Wet kit I would love to the ability to adjust my day to day fine tuning of the a/f ratio (yes, serious racers do need to tune per day their wet hits to get a/f correct) and not be messing with 16 jets. Think about that one, throw a couple dip switches or try changing out the jets with the trial error method of the past. Man it's great time to be in the game, for sure. There are numerous other new products out there, but this one is truly innovative. Anyway, watch for a complete write up coming with all findings, good, bad and ugly; as everyone who knows me knows I will tell it how it happens. Again for those that may think I am pimping for HSW, no not at this time, lol, I make 0 dollars and never have made a penny, even with any product I talk about on my site. I have never even spoken to them on the phone, just on the forums.
Robert

 

Here's the example that will show how. the long term fuel trims in our computers can adjust the fueling by up to a max of 25%. why is that needed, well as the weather changes fueling needs changing to stay at the commanded a/f ratio. A wet hit needs the adjusting if your a serious user or racer, however, it's not easy, the jets need adjusting and you need a wide band hooked up. actually how many do you know that fix their a/f ratio on their wet hits each race day? Likely that list is small. So with a wet hit no easy way to adjust for weather changes and the percent of change can be quite a bit. Now with a dry hit, because we are using the commanded WOT throttle power enrichment multiplier, it's going to make adjustment for us because it thinks we are still n/a and it's doing it's normal thing it does everyday and we are commanding a set a/f with the Interface using the stock PCM so it adjusts even for weather changes. Same reasons an EFI car is better than a carburetor car with fixed mechanical jets.
Robert

Here's an interesting tuning tid bit: Beer stated that the long term fuel trims are dropped at WOT, yes half true. here's what is happening, lets say the weather has changed a bit and the car needs extra fuel to get at the 14.7:1 a/f ratio the car runs at at part throttle, well it goes into positive fuel trims up to 25% if needed, and it can go the other way if needed and pull fuel. But here's what really happens at WOT, if the PCM has sensed that you have a lean condition and has been adding fuel-Positive fuel trims-it will freeze them and add these trims to the wot fuel multiplier. Now if your running rich and it has been pulling fuel-negative trims-it will stop pulling or drop the negative fuel trims. It's a built in safety thing. Now we can see that a/f ratio will and does in fact change day to day and the computer is on top of it, and another reason I like the new technology of the dry hit. I hope I said this correctly and trust that Beer will find anything that makes no sense, as I am tired here and going to bed.

Man this stuff gets involved sometimes to explain, and there's more to it that and wish I had time to go into.

 

No arguement here on that one

Contemplating taking the car to Doug and his gang for a gear swap and fine tuning next time home...The 500 miles each way is the only hurdle...

 

Sounds good.