Decisions Decisions Decisions...............Constructive Input Wanted

[Jookmasta]

well amongst studying long and hard, i've been trying to square away the ka-t setup so that all i will need to do is merely change the oil and do other maintenance things. currently its running fine and dandy (still could use a good retune) but other than that, all smiles. so i couldnt make a poll but here goes. i currently have an fpr, and some sexy deatschwerks 480cc injectors waiting to go in. now i have been thinking about it and i have decided that i do want an enthalpy tune. the question is not whether or not i will get the ecu tune, but if i should upgrade the injectors to the 650's. unfortunately, the cost of the upgrade is 150 bux seeing as how deatschwerks will only give me a 150 credit for them. they have never been used but i've noticed that their price has increased by a few bux or so. nonetheless, what would u do, and why?

A: slap in the 480's and get the enthalpy tune

B: upgrade the 480's to 650's and get the enthalpy tune

to clear up any ambiguities, i am running a str8 t3 (60 trim with a .63 A/R) so no lag. now from my understanding, that turbo can't do 400wrhp without becoming a heat pump. also, as for my personal goals, i would be a very happy man with 350wrhp. i mean honestly, any s13 with 300wrhp and no lag makes for a fun car. so with that said, post away and thanks in advance.

[teddy]

I was going to recommend getting some of their 555cc injectors, but seeing as theres only a $10 price difference between those and the 650's, I would say go with the 650's. Soley for the reason that you will have potential in your fuel system and room to improve should you decide to upgrade the turbo. The 650's will also be able to get you to your desired power levels without getting into a very high duty cycle.

Edit: Forgot to ask what boost you're planning on running at on a daily basis?

[Jookmasta]

i run 8psi at the moment.............1 bar would be great.................17 would be for the track? honestly the highest ive ran it at was 12 psi. the goal is to run 1 bar tho on a daily basis.

[Florida240sx]

480cc will get you to 330ish hp. Make your decision.IMO step up bigger now so no need to worry about down the road.Just wait one or 2 more weeks to get the extra cash.

[C-Kwik]

I think you'll already be stretching out the T3's capabilities on 480cc injectors if you were to max them out. I wouldn't bother going bigger unless you plan to or actually swap in a bigger turbo.

[KATwo40]

I'll pay you $150 for the 480's. I think you should upgrade. *GRIN*

[email protected]

[crzycav86]

werd.

anything over 300whp on that t3 will cause it to be a heat pump anyway, and the 480's will work well at that power level. It's just the price we pay for instant response.

[Jookmasta]

ya i was thinking the same thing after looking over the compressor map for my turbo. i guess it would be wise to stick with the 480's as maxing them out kinda equates to maxing out the turbo. as for kaw40, that's half the reason y i started the thread lol. 150 dollar credit for brand new 480cc injectors is what put me in this dilemma. if i were to sell em, im sure i could fetch 200 or so easy (hopefully).

nonetheless, keep the opinions coming as im now leaning to stickin with the current 480's. so as far as how the "poll" stands:

choice A: 2 votes

choice B: 2 votes

[deviousKA]

You know, if you were to tune the ecu yourself, you wouldnt have to worry about such things.

And you can make your changes in minutes instead of weeks.

[KATwo40]

I'm gonna go ahead and classify deviousKA's response as a "get new injectors" post.

So, to where shall I send the money for those 480's, sir?

[nissanfanatic]

You can always squeeze more power out of the 480s by turning up the fuel pressure. Trim fuel with the SAFC.

[Jookmasta]

well lemme not get ur hopes up katw040 as they arent up for sale. as for devious, i would say that is a good idea budget wise and time wise but i honestly don't have the time nor skill (soldering skills that is) to deal with the megasquirt or bikirom route. i didn't think of that cory. makes me now smile as i do have a nice sard fpr to go in also with those 480's......................keep the opinions coming tho.

scoreboard:

A: 3

B: 3

[KATwo40]

You need the 550's for fuel enrichment when you spray the 75shot.

[teddy]

Are you planning on upgrading your turbo to something bigger anytime in the future? The only reason I stated to go with the 650's was under the assumption that you are planning on going bigger sometime in the future. If you're content with the t3, stick with what you've got.

[1WheelWonder]

Stick with the 480cc and bump fuel pressure up to about 4bar, and that should net you enough fuel for 350hp.

[KATwo40]

He'll have to have the ECU tuned for this, which I'm not sure they'll do. At least not for the standard price, since the maps are based on roughly 40psi. In the end, it might cost the same as just upgrading the injectors and re-tuning.

(This was not a plug for injector purchase...just giving a little input.)

And now, for the shameless plug....

There are some 750's in the F/S section right now for $300.

[nissanfanatic]

He'll have to have the ECU tuned for this, which I'm not sure they'll do. At least not for the standard price, since the maps are based on roughly 40psi. In the end, it might cost the same as just upgrading the injectors and re-tuning.

He already has a SAFC. He can easily trim/add fuel where its needed. An ECU tune will not be necessary.

[Jookmasta]

well i really dont plan on upgrading this turbo anytime soon as i like the instaspool/boost response. so i guess the 480's would match this turbo better than. i do eventually plan on upgrading the turbo but that will be done when the engine gets built (future plans that won't take place till at least a year's time if not longer). as for them tuning the ecu for other fuel pressure, i was under the impression that the ecu would adjust the a/f's for whatever amt of fuel is being thrown out (the tuned ecu that is). and yes cory you are right, i could drop in these injectors and run without an ecu tune but i'm trying to make as much power as possible so i would like my timing to be controlled properly instead of the base retard. not to mention that at 1 bar, a base retard is nearing that endpoint where the distributor cant go much further (in relation to retarding the base timing). keep the opinions coming tho.

Poll results:

A: 5

B: 3

As for KAw40, i saw those injectors too and started to wonder but at the moment, i can't achieve contact with enthalpy as i've sent him an email and sent him an IM. so as cory said, 480's can be trimmed with my safc so they are gonna sit tight at the moment.

[nissanfanatic]

Oh no... I meant a retune for raising fuel pressure with an existing ECU tune is not needed. I DEFINATELY support an ECU tune.

[KATwo40]

He already has a SAFC. He can easily trim/add fuel where its needed. An ECU tune will not be necessary.

Why bother with an ECU tune if you're just gonna jack the base pressure 20psi over stock? By the time you change the settings with the SAFC, it'll be out of the correct load areas. A few subtle adjustments here and there aren't so bad, but compensating for a big gap like that will cause some issues, namely in high-boost areas.

[nissanfanatic]

No it won't. I corrected for 20% larger than advertised injectors. If timing and fuel are correct, then everything is gravy.

The SAFC changing timing thing has pretty much been confirmed as myth.

[KATwo40]

No it won't. I corrected for 20% larger than advertised injectors. If timing and fuel are correct, then everything is gravy.

The SAFC changing timing thing has pretty much been confirmed as myth.

I'm very interested in learning more about this. Not trying to argue with you, just trying to educate myself. Could you cite your source on the confirmation? I really don't see how it could be a myth, since you're lying to the engine about airflow entering the engine, when in fact there's considerably more, consequently resulting in a higher than perceived engine load.

Like I said, I'm very interested, so if you could point me to some literature, I'll head that way and stop jacking this thread.

Thanks.

[Jookmasta]

well i definitely have my head set on that ecu tune. sorry if i misunderstood ya cory. as for the fuel pressure increase, the safc could take care of that quite easily. a few passes on the street and the handy dandy zeitronix datalogging it makes for the slight adjustment i might need. well as for the timing and me changing the fuel pressure, well remember that the comp would now be setup with a timing map made for boost. from my understanding, the timing would still be in check due to the upgraded comp.

Poll results:

A: 5

B: 3

Keep the opinions coming.

[KATwo40]

Each timing input is referenced by a particular load cell. Even though it would be calibrated for your boost levels, you're still changing the cell the ECU refers to for reference when you alter the MAF input.

The ECU refers to the VQ table to cross reference MAF return voltage and RPM to arrive at a theoretical pulsewidth and timing value.

It is and always has been, that as load increase, fuel increases and timing decreases. If you decrease fuel (by altering load input), the ECU sees less load, consequently increasing timing.

The only type of system that comes to mind where an SAFC2 is a very very good device that won't alter the timing maps would be a select few Hondas that use Alpha N (throttle position) for timing, and speed density (MAP) for fuel. This way, when you alter the fuel curve, via MAP input to the ECU, the timing tables are untouched, since you didn't modify the throttle signal.

In short, you really need to specify your intended fuel pressure and whatnot to the person who tunes your ECU.

However, one very important factor to consider, is that some injectors have a hard time opening when fuel pressure nears 70psi or more. I don't know about the Deatchworks units themselves, but some don't have the power to pull the pintle off the seat with the supplied voltage. This causes some driveability issues, and in the worst-case scenario, a severe lean condition (because the injector is stuck shut from the fuel pressure behind it) occurs, resulting in a blown engine.

Not trying to scare you into anything, Jook, but you must explore this stuff exhaustively before you make your decision.

Honestly, if you're going to run that turbo for a couple years, use the 480's. It'll be great. But later, when you do upgrade, please, don't cheap out over $200-300 bucks. It's just not worth the risk.

[C-Kwik]

No it won't. I corrected for 20% larger than advertised injectors. If timing and fuel are correct, then everything is gravy.

The SAFC changing timing thing has pretty much been confirmed as myth.

The SAFC itself does not change the timing. It's the ECU that does. The ECU actively alters timing quite a bit based on load. Since an SAFC or Emanage alters the MAF signal, the ECU thinks there is less load then there actually is since the ECU will believe there is less airflow. Think of it this way. With a completely stock set-up, if you were to drive at a high altitude, the motor is going to see less mass flow of air than at sea level. As a result, it can bump up the timing a bit to try and maximize fuel efficiency and power for that level of airflow.

I went from a FMU to an emanage with 370cc injectors with the S14 I had and during hot days there was a bit of knock under max boost. The FMU never had that problem. I had to back off timing a bit in some areas of the engine's operating range. And as KAtwo40 said, I'd love to hear where you sourced this info. My understanding of this comes mainly from the Emanage Yahoogroups when the Emanage first came out. The SAFC works the same way in altering fuel maps. They have a lot of shop guys on that mailing list with access to dynos and datalogging equipment. I trust their judgement on this.

[deviousKA]

When you do any alterations to your maf signal via a piggy back, you are directly altering load calculated by the ecu that is used for both fuel and ignition. You are no longer running off the intended (or complete) areas of the maps.

As KATwo40 said.

[nissanfanatic]

I've monitored it via Techtom and so has Anthony. Timing does not change.

And if you look at some of Anthony's older posts, his stock ECU actually pulled timing in the correct direction(retarded) while he pulled a LOT of fuel(550cc injectors) with only an SAFC.

The technical input you guys give really does make a lot of sense as I used to spread the same EXACT info along to others who inquired about the SAFC changing timing values, but I thought differently when I had the Techtom in front of me and played with the SAFC....

[KATwo40]

Did you do this on the stock ECU or on your Enthalpy tune? Also, did you monitor the timing values under boost only, or during all points of operation?

[nissanfanatic]

Enthalpy tune. Timing values change a lot under normal conditions, so it is hard to monitor. I monitored under WOT only.. where it matters.

[KATwo40]

Enthalpy tune. Timing values change a lot under normal conditions, so it is hard to monitor. I monitored under WOT only.. where it matters.

I'd say, most likely, the ECU is tuned with the same timing values in the upper load/rpm ranges. Chances are, even though you altered the MAF signal, thus pitching the ECU into the wrong load cell, you saw no timing change becaue the timing values were the same in those cells. Remember, the ECU interpolates between cells, in a square area of a few cells.