can i run 3-7 psi with a returnless?

[hyunpower]

can i run a safc with stock injectors on a 02 xd on (3-5 psi) and move up to 7psi with the sonata 2.4L injectors aftherwards without running a return line to the fuel tank..?

I know the safc can control all that under boost conditions

[Havro]

sure why not!

[Elantra2.001]

The Koreans have proven that 300 whp is the limit for the stock fuel system. So basically you can run up to that point before converting to a return system through the use of larger injectors and a fuel management solution like the SAFC.

[FordFasteRR]

I do not suggest running any amount of boost on stock injectors unless you have a supplementary injector controller ...

based on my calculations using the injector calculator here: http://www.nitrousworld.com/elantra-injector-tech.php
I found that the stock injectors do not have enough extra flow capacity to support more horsepower..

for example, the stock injectors are about 190 cc ... they support 135 stock hp at .80% duty cycle...

for the fuel system to support 150 hp.. you have to push the stock injectors to 90% duty cycle... that is unacceptable and could easily damage the injectors or lock them up !!!!!!! YOU DONT WANT THAT TO HAPPEN under full throttle boost conditions do you ?

now... .. for the stock injectors to handle 160 hp.. they need to be pushed to 96% duty cycle... again, unacceptable !!!!!!!!!!

Thank about this and the you decide what you want to do.

[NCspecV81]

werd...the higher the duty cycle...the more constant the failure rate...=o) hate to be doing a hard run and have them go out!

but anyways..just thought ide let you guys know...aai turbo systems..used this with their boosted spec...made 289whp @ 8psi using the stock injectors and returnless system...of course...upped the fuel pressure a ton with an inline 255lph...but used this for fuel management...

just a thought

http://216.242.145.16/products/product.phtml?p=32

imho..if you wanted to keep the returnless i would go with that fmu...255lph inline...bigger injectors..and safc2..but kinda pricey! might as well just convert to a return system...throw on an safc2 and a rising rate fpr w/ bigger injectors.

[FordFasteRR]

you have a point with the pressure differential... You can have more fuel as long as you increase the pressure, but anything above 100 psi can also cause damage to the injectors and possibly lock them up, thats just as bad as overloading the duty cycle...

My point is, you can achieve your fuel control goals by simply installing the larger sonata injectors and using a safcII to tune the system.

:) And you can save considerable time in developing a custom fuel system..

Also, upgrading the injectors + SAFCII is a proven reliable setup that you can do easily.

:)

[Elantra2.001]

Yeah the larger injectors and SAFC are proven to work with the stock fuel system. No need for a return.

[NCspecV81]

Yeah the larger injectors and SAFC are proven to work with the stock fuel system. No need for a return.

i do believe that would be a good setup for someone on a budget and only plans to boost a very few psi...once you get into some higher #'s...youll need something there to adapt the fuel pressure when boost is present in the system....and on top of what about fuel supply? the pump...youll need to convert to a return system in order to utilize an intank higher liter per hr pump....ultimately it would be best to go ahead and conver to a return system while you are doing the fuel system..less hassles later on and the ability to run higher boost and more hp.

[Havro]

our stock system is good to 300whp.....
were not running elantra funny cars at the drag strip
hes asking for 3-7 psi.....
ur running 10 psi at 300whp....so i think if hes running 3-7 then he is ok!
if he wanted to run more than 7 after a while he would of said "i plan on running over 7 once i get bored with 220-240 whp"
everybody likes to throw around there money....

[FordFasteRR]

our stock system is good to 300whp.....


I agree... considering that the stock fuel system runs upwards of 60 psi at wot with no return line, that means that there has to be considerable amount of flow capacity to keep the pressure up...

if one was to add a return line and a regulator at the rail, you will also have to change out the pump... this leads to all new sorts of problems but for the low boost levels that he needs, he can keep the returnless system and just utilize larger sonata injectors + safc to tune the system.

sure, the safc 2 wont compensate for boost unless he rigs it with an extra map sensor.. .but at least he has that option...

for low boost setups it wont make much difference as long as he sets it rich enough to keep it from pinging at wot and full boost.

[Elantra2.001]

Yeah we know about return systems. Im converting to one. But im going for more horsepower than the stock system can provide. So for Hyunpower, the injectors and SAFC will do what he needs, up to 300 whp. Your car might be different and cant support that much on the stock system, but seeing as its been done several times, and we have done research on the Elantra, which is the car in question here, not a Sentra, no return is needed for his application.

[Havro]

does the sentra guy even own a hyundai...or is he just jealous and comes here to check out or pimp rides?

[Elantra2.001]

No he does contribute, but we know this setup to work and a return isnt needed.

[NCspecV81]

i never said the returnless system wasnt good for low boost..i even considered it...but if you know you are going to run higher boost...might as well make everything right the first time...the boost bug bites hard fellas...regardless of what car i have...im trying to help here..a more reliable setup would be a return line...rising rate fpr to handle increase in fuel pressure when boost goes up...<--that is very important...reason why ALL factory turbo cars are return systems...and a fuel pump with more capacity..if you pay attention to my first post...i even supported the fact of doing a returnless fuel system...but regardless of which style system you wanted...you need a way to increase fuel pressure in relation to boost.

[FordFasteRR]

[QUOTE=NCspecV81]ALL factory turbo cars are return systems...[QUOTE]


hmm... I disagree... the dodge neon SRT-4 uses a returnless fuel system and it makes 245 hp stock...

[NCspecV81]

[QUOTE=NCspecV81]ALL factory turbo cars are return systems...QUOTE]


hmm... I disagree... the dodge neon SRT-4 uses a returnless fuel system and it makes 245 hp stock...


okay i missed one =o)..now that i know that...i only know of 1 now. :D


but im sure they have a way to increase fuel pressure once boost in present.

[FordFasteRR]

okay i missed one =o)..now that i know that...i only know of 1 now. :D


but im sure they have a way to increase fuel pressure once boost in present.

you are right... the car uses a map sensor and the ecm reads boost and adds fuel accordingly based on the 3d fuel maps programmed in at the factory...

:)

[Havro]

is this thread gonna end up in Flame department???

:angryfire :diablo: :owned:

[Mahonroy]

So even for the 04 CVVT Elantra (MAF sensor, and returnless fuel system) this way will work also? (a SAFC-2, and sonata injectors) Thanks!

[Elantra2.001]

Yeah that will work for the 04 also, perhaps even easier since the MAF sensor can see higher air flow levels than the MAP sensor can.

[NCspecV81]

the reasoning behind upping pressure while in boost is b/c the underside of the injectors see increased pressure as well...making it harder to flow X amount of gas...now when you up the pressure..you compensate for the extra work the injectors have to do when pressure is exerted on them by increasing the pressure of the spray...reasoning why its IMPORTANT to have something to increase fuel pressure when boost is present in the manifold.

[FordFasteRR]

specv... you have a point about the pressure differential at the injector nozzles...

but please dont forget about pulse rate... the higher the pulse rate, the larger amount of fuel will come out of the injectors, the only time you will see a problem is if your boost level is so outrageous that it could possibly push back on the injector nozzle so hard that the fuel flow is reduced... luckily this doesnt happen unless you have more boost than fuel pressure.... or close to it.... since the nozzle size is so small, its hard for the boost pressure to push back on it anyway....

[Elantra2.001]

The stock system already will increase pressure to 60 psi.

[NCspecV81]

its not the amount of gas that comes out...the pressure at which it comes out as...ecu wasnt made to sense boost..so therefore it wont increase fuel pressure with boost...so every psi of boost in the system needs to be counter-acted on the other side of the injector...your ecu still thinks the stock injectors are in there...yes the pulse width will stay open the same amount...but you havent increased pressure..that pressure will hold back the flow of the injectors unless like i said...its counter acted with pressure on the other side....i have no problems with doubting the returnless system...im just saying...no matter what style, return or returnless, you need a way to increase fuel pressure in relation to boost pressure...if you run x amount of boost...an x amount of fuel pressure needs to be induced to counter-act x amount of extra pressure excerted on the fuel injector.

[Elantra2.001]

Thats exactly why we dont need return lines for that low boost. We arent raising the boost level high enough with that low setting to require us to compensate for the added pressure in the manifold. The longer pulse and duty cyle will compensate provided you use a dyno or O2 sensor to tune the system, you can over come that. Now im shooting for 20-22 pounds of boost right away so sure im going to return. I already have a rrfpr and a stand alone with the fuel pump ready, so we see your point but at the levels hes asking about, there is absolutly no need to go with a return.

[Havro]

20-22 pounds....good luck....

[carbonman]

lol, he won't need luck, he'll need knowledge and research which he already has ;)

ncspecv - I think some of the info has been clouded with generalizations as to what works on other cars in this thread. I beleive there was issues with a Ford Focus (in SCC?) utilizing the returnless system.
However, the korean shops that I've talked to over the last 2-3 years have all informed me that they can boost up to aprox 300HP utilizing mostly stock internals (bar pistons) as well as the stock returnless system. You are correct though in making the point that an increase in pressure or adjustment in fueling is required with the use of a piggy-back system.

[Steve]

This is getting me all worked up! Just the thought of needing less hardware to turbo my MAF '04 is freaking me out even if it's not in the budget for awhile... son of a ..... damn.... f... sh.... arrrrr.

[FordFasteRR]

yes, the maf based cars are as easy to setup as the map based cars... all you need is an aftermarket fuel tuner and larger injectors and you are set for around 10 psi easily... maybe even more with the stock fuel pump system....

[Elantra2.001]

lol, he won't need luck, he'll need knowledge and research which he already has ;)

ncspecv - I think some of the info has been clouded with generalizations as to what works on other cars in this thread. I beleive there was issues with a Ford Focus (in SCC?) utilizing the returnless system.
However, the korean shops that I've talked to over the last 2-3 years have all informed me that they can boost up to aprox 300HP utilizing mostly stock internals (bar pistons) as well as the stock returnless system. You are correct though in making the point that an increase in pressure or adjustment in fueling is required with the use of a piggy-back system.

Fo Reel.

[NCspecV81]

Thats exactly why we dont need return lines for that low boost. We arent raising the boost level high enough with that low setting to require us to compensate for the added pressure in the manifold. The longer pulse and duty cyle will compensate provided you use a dyno or O2 sensor to tune the system, you can over come that. Now im shooting for 20-22 pounds of boost right away so sure im going to return. I already have a rrfpr and a stand alone with the fuel pump ready, so we see your point but at the levels hes asking about, there is absolutly no need to go with a return.


any amount of pressure over 0 boost is going to hender the way your injectors flow...you arent going to get any extra fuel pressure from the ecu b/c the ecu wasnt setup to see positive pressure in the manifold...if you have .5psi over 0 boost in your manifold...you need to compensate for that .5psi regardless of a returnless or a return system....most n/a cars wont even see 0(zero) boost anyways..especially if you are up in elevation...im not preaching return or returnless..im just saying if he wants to do a returnless...do it right...get an fmu adaptive to a returnless system that will induce fuel pressure when there is positive pressure in the manifold..thats all im saying...its even possible that he may not even need an safc2 using a returnless system and returnless fmu...aai for the spec uses that aeromotive fmu for returnless systems...and dont even use an safc2..just tunes using the fmu

[Mahonroy]

I heard that you can't use an Apexi SAFC-2 on the 04's? I don't see why u can't, but here is the post...:

Quote:
Originally Posted by Steve
So what about the '04 XDs. The front O2 sensor is a linear (wide range) sensor.



they should run in open loop all the time...which an safc2 wouldnt be possible..thats the problem some 04 se-rs are running into b/c some have a wideband o2

Any thoughts? I am eager to order one and get it installed either by myself or from a dealer...but now I am hearing that u can't use it with an 04?

[NCspecV81]

I heard that you can't use an Apexi SAFC-2 on the 04's? I don't see why u can't, but here is the post...:

Quote:
Originally Posted by Steve
So what about the '04 XDs. The front O2 sensor is a linear (wide range) sensor.



they should run in open loop all the time...which an safc2 wouldnt be possible..thats the problem some 04 se-rs are running into b/c some have a wideband o2

Any thoughts? I am eager to order one and get it installed either by myself or from a dealer...but now I am hearing that u can't use it with an 04?

yes thats true as well...but you can buy an o2 clamp like the mazdaspeed guys and use it..

[FordFasteRR]

nc, can you explain to me what the hell the o2 sensor has to do with the maf sensor ?

The SAFC hooks to the MAF / MAP sensor... not the o2 sensor.. so what difference does it make if your car had a wideband o2 or not ?????????

[NCspecV81]

ford-

the reasoning behind this is b/c with a wideband o2 sensored car...the car will always run in closed loop...therefore its always going to try to achieve the a/f ration it was programmed to see...now you can make changes and install an safc2 sure...but...we all know that obdII ecu's are adaptive...and when the car is always in closed loop using o2 readings to determine a/f ratio(this is b/c of the wideband o2 sensor, as ecu's with widebands never go out of closed loop operation)...its going to learn its way around the safc2 and make changes via the readings on the o2 sensor to change to said a/f ratio (voltage) ecu was programmed to be seeing.....now this is a different story for narrowband o2 cars as when @ wot the car goes into open loop only using maf readings...=o) now you must see where im going...with the o2 sensors being out of commission (not being used to determine a/f ratio) you can now alter the maf voltage to a specific voltage via aka the safc2 to deliver the correct a/f ratio you need in conjuction with the fuel system and limitations....

but like i said...cars that have wideband o2 sensors never go out of closed loop operation...thats why i said that if you have a wideband o2 you would need a clamp..its basically like a rear o2 sim...the ecu will think its getting said voltage out of the primary wideband o2...that way you can alter the maf readings as you please as the ecu wont attempt to change a/f ratio b/c the wideband o2 voltage would be in spec...basically making it run in open loop even though in actuality its not.

[Mahonroy]

Crist does this stuff get complicated... Ok so if my car is going to try and make the air to fuel ratio what it was programmed to do, then I don't really need to alter the current fuel system at all then right? Just throw in a little bit bigger injectors and the computer will take care of tunning the air/fuel ratio then? No need for safc...?

[Elantra2.001]

You can compensate for low boost like i said by increasing the duty cycle or pulsewidth for the lack of a pressure differential in the manifold. If you notice here we keep saying LOW BOOST. We know there are other things needed to go higher but for LOW BOOST you can adjust for the increase in manifold pressure with the larger injectors and a controller. Now if the "wideband", and i use that loosely because its not a true wideband depite being closed loop only, always attemps to achieve an ideal fuel air ratio... larger injectors should be scaled back by the ecu at idle and as RPM's increase, it should compensate with out any fuel controller up to a certain point which i doubt has been found yet.

[FordFasteRR]

....do i Just throw in a little bit bigger injectors and the computer will take care of tunning the air/fuel ratio then? No need for safc...?


no.

after swapping larger injectors... the ecu cannot trim the injector pulse that low by itself... you need to trick it by using a safc or other similar fuel tuning device....

if you try this, you might get away with a few hundred miles of driving before the plugs foul to the point that the car stalls and it will not re-start until you change the plugs.

also, you will douse your cylinder walls with so much fuel that it will seep down into your oil and next thing you know you'll have a blown motor.

[NCspecV81]

regardless of how much boost you run...in an n/a car to turbo...you need to inlarge the injectors, increase fuel pressure when boost is present in the manifold, a way to adjust fuel (safc2 or similar)...and for cars with a wideband you need a wideband primary o2 clamp

[FordFasteRR]

i spoke to nc for a while on AIM... apparently, some people with the wideband o2 sensors on the sentras have swapped out to larger injectors and the stock ecu system is so adaptive that it compensated perfectly without the use of an apexi safc device...

My suggestion is for someone to try this on an 04 beta 2 with the sonata injectors... see if the car runs the same after the ecu adapts...

if that is the case, you should be good to go with a bolt-on turbo kit without the use of an aftermarket controller....

although this is of course... hypothetical...


edit... apparently i was mistaken... he said that the ecu on obd2 cars with standard o2 sensors is extremely adaptive during closed loop operation and that you can up the injectors without the use of a safc for normal daily driving, and that the problem is apparent at WOT when the system switches to open loop mode in which case the injectors will drown the motor in fuel unless you have boost :)

[Mahonroy]

So is it confermed that if I order bigger injectors from hyundai (sonata injectors) and I replace them right now (every thing else on the car is pretty much stock) that the car will drive around like nothing changed unless I push the pedal all the way down, then it won't work because too much fuel will be added? What would be the solution to this problem? Thanks!

[cclngthr]

I would not swap out injectors unless I was adding boost to the engine.

[Mahonroy]

Wouldn't it be a good idea to get the car working properly with fuel before the turbo gets put on? Because eve if there was a turbo on and I swaped out the injectors, low RPM's and the turbo is barely doing anything, which would be pretty much the same thing as no turbo for the moment with bigger injectors...right? lol

How is there a way that I can figure this stuff out for certain? Like someone to ask, a book to read, etc.. Thanks!

[cclngthr]

I know the Sonata injectors would flood the engine in the stock setup, especially at WOT. There has been discussion about this here, so do a search. You also don't want to create drivability problems before you turbo the engine either.

If I were going to turbo my XD, I would first get a doner engine (beta 2) and build it to my specifications. First, you have to lower your compression, and forged pistons and rods are necessary for this (less apt to blow and detonate less), plus when you replace the rings, you need to machine the cylindars to get the new rings to seat right (or you would burn oil like crazy). Additionally, you would have to manage you fuel to compensate for the boost levels and have an ecu that supports the boost with no codes coming up.

Take care of your internals first. Your engine can run with lower compression ratios even with little or no boost, but your top end power might be lower.

[Mahonroy]

What I was hoping for was replacing the injectors, and then installing the plumbing for the turbo, and leave it at that(and set it to around 5 psi). So only WOT the engine will flood and u would need a MAFterburner, SAFC, or ARC-1, etc. to control at WOT, and when its not WOT then it will work properly because its using the o2 sensor signals to adjust?

[cclngthr]

Maybe. The o2 sensors will only do so much adjustment based on the mapping of the ecu. A SAFC could compensate the limitations the ecu has, but a remapped ecu might be better, and would have less problems with codes coming up. I know R.E.A.L. Engineering has been able to configure an ecu that is able to do this, but I don't think they have done long term testing on it, which disappoints me because the thing I am concerned with in addition to the long term effects of fuel management is the emission control system and how legal the car is (due to the many areas requiring emission sniff tests).

[Elantra2.001]

If you get injectors, do yourself a favor and get a controller.

[adeihl]

Actually. it would prob be better if someone posted who actually DID this injector swap..

there is alot of misinformation around.

You can use these 290cc's in a stock tiburon. That is thanks to a little thing our ECU calls fuel trims. you will prob me at about -15-20 on the ST and LT FT's

Hence.. after driving around for about a day part throttle ONLY you WILL be able to give it WOT with no issues.


BTW the MAX you can go on these injectors while cheating the fuel trims is 4 PSI. this is at around 12:1 at 4k ( this is our lean spot and unfortunatly the point where we have to worry about hitting the leanest...) if you want to be daring you might try 13:1 on 94 research for 5 PSI. but I wouldnt ;-)

Andrew

Andrew

[Mahonroy]

So the problem with what you said is it has a tendency to want to lean out e.g. air fuel ratio would go in a somewhat fassion of 13:1, 14:1, 15:1, 16:1, then would detonate? I thought that the main problem without adding a fuel computer was that it would be running too rich? e.g. below 12:1 or 11:1? Does the Elantra try and make the air/fuel ratio around 14.1:1?

[cclngthr]

No, the fuel computer manages the mix to handle the increased airflow; which more fuel would be required especially at WOT. When you add more air, you need more fuel. However, if the compression is too high, the mix would fire off too easily under the intense compression, which it can fire too early, or even too late if the conditions are just right.

Under no boost, which is at idle or low rpm, you don't want the extra fuel to be there, but when you open it up, you need to have that fuel ready to spray in the engine. The fuel computer manages the mix under both conditions.

I would also lower your compression to 8:1 because the higher pressure causes the fuel to ignite too easily (as stated above). You would be able to run regular gas, plus keep the engine components from destroying themselves.

[adeihl]

So the problem with what you said is it has a tendency to want to lean out e.g. air fuel ratio would go in a somewhat fassion of 13:1, 14:1, 15:1, 16:1, then would detonate? I thought that the main problem without adding a fuel computer was that it would be running too rich? e.g. below 12:1 or 11:1? Does the Elantra try and make the air/fuel ratio around 14.1:1?


Our ECU will attempt to maintain 14.7:1 a/f at all times on closed loop conditions. open loop ( WOT) will be refrenced from the STFT and LTFT accordingly

Andrew

[Steve]

STFT LTFT WTF?

Better question! What's the name of that "turbo bible" book again?

[adeihl]

maximum boost..


corkey bell

read it...know it... love it....

;-)

[Mahonroy]

Yeah I'v read the entire thing front to back once, and have re-read other several parts, excelent book!

Also, can anything bad happen if lets say I ordered 290cc injectors and I just installed them in the car and tried it out? I meen if it does flood the engine does anything bad happen? Or does the car just stall and no big deal? Can u just re-install the old ones and everything is back to normal as if nothing has changed? Thanks

[adeihl]

yes you can

[dmdicks]

STFT = Short Term Fuel Trim
LTFT = Long Term Fuel Trim

STFT is the ECU adjusting the PWM Pulse Width Modulation of the injectors to increase or decrease injection time. This number will fluctuate a lot during normal low load, low throttle (Close Loop, reading O2 meter) conditions. The ECU also uses the average of this number to adjust the LTFT.

LTFT is what is added or subtracted from the preprogrammed Fuel Table stored in the ECU for WOT driving.


Make sense?

[Steve]

Yes it does thank you, I'm ordering that Maximum Boost book soon, that way by the time I've got it all in my head, I'll be ready to afford to put it all into practice, unless I do something stupid before then like buy a 2005 Tiburon V6 6spd instead.

[Mahonroy]

If you read this topic http://www.elantraxd.com/forums/showthread.php?t=2869 now people are saying that 290cc injectors are not big enough (or only enough for up to 3psi) so does this mean I would need like 350-450 sized injectors? Is there a place where I can find these cheaper than 500 off of kspec? And if so, how will the elantra run with these injectors in and changing nothing else? (I also heard that there is tunning problems with a SAFC for 450cc injectors from the same topic, so how are u supposed to turbo anything? lol :rolleyes: ) Any help is greatly appreatiated

[dmdicks]

Its all in the tuning. I've got the Alpine kit that includes a 65lb 5th injector. I've upgraded the kit with a SAFC and 290cc injectors. I'm currently running 17psi with nothing done to the engine except the head spacer, and I've got a WOT A/F ratio of 10.3:1. I've got room to grow!! All this on BetaII with a stock fuel pump and returnless fuel system. :D

[Madhatter]

lol...

no you cant just put in better injectors and expect your car to drive fine stock....

your engine will idle VERY poorly. You MUST controll the injectors with a fuel management system based upon boost levels and rpm.

Let me put it this way...we tuned my car NA with 290cc injectors (just for kicks to see how muchpower we could get out of it) i had to have my settings for fuel delivery at about -50% at 700rpm.. The engine will idle spiratically and go up and down without controll... your car doesnt know what to do! it is getting all this fuel so it cuts it out, then it doesnt have enought...this is not just something you can do and not controll it.

[Beta2cvvt]

werd...the higher the duty cycle...the more constant the failure rate...=o) hate to be doing a hard run and have them go out!

but anyways..just thought ide let you guys know...aai turbo systems..used this with their boosted spec...made 289whp @ 8psi using the stock injectors and returnless system...of course...upped the fuel pressure a ton with an inline 255lph...but used this for fuel management...

just a thought

http://216.242.145.16/products/product.phtml?p=32

imho..if you wanted to keep the returnless i would go with that fmu...255lph inline...bigger injectors..and safc2..but kinda pricey! might as well just convert to a return system...throw on an safc2 and a rising rate fpr w/ bigger injectors.

If I have a bigger injectors that are 4 x 550cc which is almost 3 times larger than stock, does that mean I do not need a rising rate fpr and can still support up to 350bhp with the stock returnless fuel system? So basically I only need a SAFC2 or unichip to trim down for idling?

i spoke to nc for a while on AIM... apparently, some people with the wideband o2 sensors on the sentras have swapped out to larger injectors and the stock ecu system is so adaptive that it compensated perfectly without the use of an apexi safc device...

My suggestion is for someone to try this on an 04 beta 2 with the sonata injectors... see if the car runs the same after the ecu adapts...

if that is the case, you should be good to go with a bolt-on turbo kit without the use of an aftermarket controller....

although this is of course... hypothetical...


edit... apparently i was mistaken... he said that the ecu on obd2 cars with standard o2 sensors is extremely adaptive during closed loop operation and that you can up the injectors without the use of a safc for normal daily driving, and that the problem is apparent at WOT when the system switches to open loop mode in which case the injectors will drown the motor in fuel unless you have boost :)

How adaptive is the obd2 with the standard o2 sensors? & how much can it cut back on the larger injectors? 290cc,350cc,440c,550cc or even 630cc? anyone got a change to experiment with it?

[mayollo072R]

If I have a bigger injectors that are 4 x 550cc which is almost 3 times larger than stock, does that mean I do not need a rising rate fpr and can still support up to 350bhp with the stock returnless fuel system? So basically I only need a SAFC2 or unichip to trim down for idling?


How adaptive is the obd2 with the standard o2 sensors? & how much can it cut back on the larger injectors? 290cc,350cc,440c,550cc or even 630cc? anyone got a change to experiment with it?


I'm running 290cc injectors with 5psi WG spring no ECU, no FMU, no any kind of FM or chip, etc with absolutely no pining or ponging in the engine at 5psi (by gauge and at top RPM), no drawning, etc. It just runs fine. The only thing is that the cel is on but I don't care. If it bothers you, remove it. :D

So you can start with that. Using large injectors may need a fuel remap and a lower compression. 550 and 630 injectors are often use with 14psi setups and up thus, with the current compression, you're engine might blow after a few runs.

Man, my car is not cvvt so I don't exactly know how it will work on yours since yours is maf and all the other new ****.