550s or 650s

[danyz250f]

I have heard that 550 cc injectors can be good up to 20 lbs of boost but if 650s cost the same would it be better to use those and just not max them out as much. These will be tuned off of a safc 2. Also do i have to mod my stock mass air flow sensor at all.

 

[JDNSBR]

Since you already have the SAFC, work with it. For your setup it will be fine and you will be able to get a decent tune out of it. If you ever upgrade to bigger injectors or turbo then I say DSM link. Untill then save your money and the SAFC will work fine.

 

[JDNSBR]

what if i ran 650s and only did like 80% duty cycle. Then would that be ok to because i really dont want to be maxing out or running lean. and if the 650s are the same price why not get those?

They would be the best choice. So again you are not running higher than 80% duty cycle as stated above in my previous posts. Especially if they are they same price.

 

[2gGSX]

what if i ran 650s and only did like 80% duty cycle. Then would that be ok to because i really dont want to be maxing out or running lean. and if the 650s are the same price why not get those?

As people were saying, to compensate for 650's you have to take out upwards of 30%. The AFC accomplishes this by removing airflow seen by the ECU. When this happens, the ECU attempts to bump up timing and this is why people say the AFC has problems dealing with 650cc size injectors and up; you get more timing than usual and causes a tuning problem. This may or may not be a good thing however; if you can run this much timing without any knock then by all means power to you, but most people will have troubles doing that on pump gas.

My calculations with 550's were just to show you that they are more than capable of flowing enough for what you need, unless you're trying to ludicrous amounts of power on pump (i.e. above 38 lbs/min)

 

[danyz250f]

ok sweet i am going to get the 650s and does it matter what kind of injector i get like the ball type or the regular type.

thanks for the help rep points for everybody

 

[JDNSBR]

ok sweet i am going to get the 650s and does it matter what kind of injector i get like the ball type or the regular type.

thanks for the help rep points for everybody

No problem man that is what we are here for

When you say regular style do you mean pintle style? I would say ball and here is why...

Pintle has one single stream as a ball style has a "disc" with many holes to get a more even spray of fuel. This way your fuel delivery is more efficient.

Jon
SBR

 

[danyz250f]

i'll go with the 650s with the ball style

 

[JDNSBR]

Keep us up to date on how things go!

 

[ilikespeeding]

So, you pretty much have 3 different setups. P

Pretty much:
Fast, Cheap, Reliable. Choose any two.

Fast & Reliable
255 lph
AFPR
DSMlink
650 cc injs

Fast & Cheap
190 lph
SAFC
650 cc
AFPR

Cheap & Reliable
255 lph
AFPR
SAFC
550 cc

This is what I have gathered by listening. I plan to run cheap and reliable <-- has enough bang for me...or fast and reliable. I just dont wanna be stuck on the side of the road again. My motto is if its worth doing, its worth doing right...#### half-assing

 

[blcknspo0ln]

irregardless of what fuelpump or inj. size you use (550 or 650) your car will not become any more "reliable" or "unreliable". it has to do with your competenancy to tune the car. No you don't have to be a rocket scientist to get a 650/SAFC car running great for DD... all you need is a logger and a couple hours of tuning.

it's not that hard, really it isn't..

 

[IMPORTIMAGE]

Im currently maxing out my 650's on my EvoIII 16g turbo. I ordered some 850's...I bet 650's would be ok for your car.

here is my setup-
Evo 3 16G turbo ported
SBR Exhaust manifold (ported)
SBR dump 02 housing
650cc injectors
SBR Race FMIC with J pipe
Arp Head Studs
HKS 272 Cams
Turboxs Dtec Boost controller w/gameboy screen
Turboxs Bosch Wideband Tuner
(not installed yet) Cooling Mist/Import Image Water Injection Kit
upgrade AFPR
Prothane mounts
2g Maf with honey combs out because we were maxing it out
1990 dsm ecu w/eprom Custom chip burned
Walbro fuel pump
Greddy Rs blow off valve
gauges
Apexi-SAFC
act clutch
Dejon tools intake tube
Vibrant filter and adapter
Palm pilot with data logging
full exhaust
Spark Plugs
Water Wetter
balance shaft elimination kit
BG synchroshift
Complete gasket kit
Im sure there are more mods but i forget...

 

[Venom55]

Im currently maxing out my 650's on my EvoIII 16g turbo. I ordered some 850's...I bet 650's would be ok for your car.

here is my setup-
Evo 3 16G turbo ported
SBR Exhaust manifold (ported)
SBR dump 02 housing
650cc injectors
SBR Race FMIC with J pipe
Arp Head Studs
HKS 272 Cams
Turboxs Dtec Boost controller w/gameboy screen
Turboxs Bosch Wideband Tuner
(not installed yet) Cooling Mist/Import Image Water Injection Kit
upgrade AFPR
Prothane mounts
2g Maf with honey combs out because we were maxing it out
1990 dsm ecu w/eprom Custom chip burned
Walbro fuel pump
Greddy Rs blow off valve
gauges
Apexi-SAFC
act clutch
Dejon tools intake tube
Vibrant filter and adapter
Palm pilot with data logging
full exhaust
Spark Plugs
Water Wetter
balance shaft elimination kit
BG synchroshift
Complete gasket kit
Im sure there are more mods but i forget...

If your maxing your 650CC with ONLY a 16G EVO3 their something wrong in your tuning. I mean all my friend are running 16G EVO3 and 550 and they went 11.69 and some low 12 with only 550 and SAFC.

Im pretty sure you need tuning cuz 650CC are enough for a 50trim

 

[2gGSX]

If your maxing your 650CC with ONLY a 16G EVO3 their something wrong in your tuning. I mean all my friend are running 16G EVO3 and 550 and they went 11.69 and some low 12 with only 550 and SAFC.

Im pretty sure you need tuning cuz 650CC are enough for a 50trim

Are your friends on 550's running race gas or pump gas when they went 11.69?

 

[RiceKiller_TSi]

I don't have timeslips but I've run 23psi on the streets all day long with my 550's. And they didn't go over 80%. And THATS at stock fuel pressure and only 4 counts of knock. If I bumped up the fuel pressure it would be ridiculous... I would need a bigger intercooler before I ran outta fuel.

 

[Dorifto]

I'm right up there with RiceKiller - my GS-T is tuned for 20psi on 91 octane, running 550cc injectors and Walbro 255 pump. To the best of my knowledge, these injectors haven't been maxed out, but I don't know for sure. I'll have to check out the EMS settings when I get a laptop and AEM's software [damn previous owner losing stuff ].

I believe I'm running above stock fuel pressure, but I can't honestly tell you, I haven't checked out this car thoroughly enough since I've bought it. If I'm not having problems [fueling anyway ], then you should be plenty fine.

-Dave-O

 

[tunitallstar]

Im currently running 550s, and having no problem on a 20g. I would like to go bigger, but I do not have the money. But I will got to probably 750s or so.

 

[Apeximprt2nr]

What exactly does "Injector Duty Cycle" Mean?

 

[JDNSBR]

What exactly does "Injector Duty Cycle" Mean?

Injector duty cycle basically is how much the injector is dumping fuel. If you are running at 0.85 IDC that means that at max power the injector will be open 85 percent of the time in order to provide enough fuel to make the horsepower needed.

This is also affected by fuel pressure, because as pressure goes up, volume goes up, and as pressure goes down, volume goes down. Hence the reasons for a FPR.

 

[Apeximprt2nr]

So, more boost would increase injector duty cycle? And what is a good "range" for the IDC to be at?

 

[JDNSBR]

75-80% Is a good range for our cars. That way it is not over working the injectors as previously stated.

 

[manwithaGSX]

I am currently deciding between these two injector sizes as well. I followed the links I found in these posts, did some calculations using the formulas in this thread. I was wanting about 350 at the crank and the formulas put me right at the 650cc marks(calculations ended up at 653cc/injector). Looking at the flow charts at http://www.vfaq.com/mods/Walbro-specs.html , a 190 should be able to flow enough fuel at 16, 17 lbs of boost to get 350hp at the crank. Keep in mind that my calculation plan for 80% or 85% IDC and I'm going to go ahead and do the fuel line upgrade as shown here http://www.stevetek.com/R-FuelSys.html

My questions is would anyone disagree that a 14b, 190 pump and 650 injectors could produce 350hp safely?

Were my calculation wrong and I could do the same with 550's with no more than 85% IDC?

Also will using the MAF-T 2.1 (set up for blow through)for adjustments be adequate for tuning?

My current mods list in my profile is accurate, but during the next two weeks a 3" turbo back will be installed along with balance shaft removal. At the same time a head rebuild with Manley springs and ARP studs will be done. ALL boost leaks will be fixed and the fore mentioned SS fuel line upgrade as well.

Should I have started my own thread???????? this one is a month old.

 

[JDNSBR]

I am currently deciding between these two injector sizes as well. I followed the links I found in these posts, did some calculations using the formulas in this thread. I was wanting about 350 at the crank and the formulas put me right at the 650cc marks(calculations ended up at 653cc/injector). Looking at the flow charts at http://www.vfaq.com/mods/Walbro-specs.html , a 190 should be able to flow enough fuel at 16, 17 lbs of boost to get 350hp at the crank. Keep in mind that my calculation plan for 80% or 85% IDC and I'm going to go ahead and do the fuel line upgrade as shown here http://www.stevetek.com/R-FuelSys.html

My questions is would anyone disagree that a 14b, 190 pump and 650 injectors could produce 350hp safely?

Were my calculation wrong and I could do the same with 550's with no more than 85% IDC?

Also will using the MAF-T 2.1 (set up for blow through)for adjustments be adequate for tuning?

My current mods list in my profile is accurate, but during the next two weeks a 3" turbo back will be installed along with balance shaft removal. At the same time a head rebuild with Manley springs and ARP studs will be done. ALL boost leaks will be fixed and the fore mentioned SS fuel line upgrade as well.

Should I have started my own thread???????? this one is a month old.

Yes, a 190 pump, 14b, and 650cc injectors are very capable of this with the correct mods. Especially to the crank. You will see a better chance of your goal with the exhaust. However, every car is different. You will be very suprised what race gas, and a very good tune will do.

 

[wt71gas]

I am running 650cc's with SAFC2 and I make decent power with it and the car has no driveablity issues at all. You can definately run 650cc's and get away with the SAFC2 without problems

 

[My96AWD]

I have heard that 550 cc injectors can be good up to 20 lbs of boost but if 650s cost the same would it be better to use those and just not max them out as much. These will be tuned off of a safc 2. Also do i have to mod my stock mass air flow sensor at all.

or you could get a 2g mass and 550's and bolt on and go with no tuning.

edit: you would still need to richen up your mixture. i did some searching and found this.

Well, since you resurrected this thread, just for the record the 2G MAS flows 29% more air for the same Karman Hz, not 20%. For years, people said the 550's and a 2G MAS was an even-up proposition, but it never worked in my car, and I found out why once I hacked the chips. With the 2G MAS removing 29% airflow, and the 550's only adding 20%, you are still 9% too lean, and you are WAY off on the timing maps, so you have to add fuel to keep the knock down. Hey, it works great on race fuel: it leans your A/F out, AND gives you more timing. But, it sucks for pump gas, no matter what people say. I raised my fuel pressure to 49-50 psi, and it still was too lean. The only right way to do it, besides a chip, is to add 29% on an AFC.

 

[JDNSBR]

or you could get a 2g mass and 550's and bolt on and go with no tuning.

WTF So...you want him to run like crap, not be happy, and have horrible gas mileage?

 

[blackGSX2g]

If your maxing your 650CC with ONLY a 16G EVO3 their something wrong in your tuning. I mean all my friend are running 16G EVO3 and 550 and they went 11.69 and some low 12 with only 550 and SAFC.

Im pretty sure you need tuning ### 650CC are enough for a 50trim

I agree. I bolted up my PTE 5031 and boost crept to about 25psi and I logged about 130% IDC on RC 550s.

I currently run FIC 650s with a non-rewired 190 pump and 25psi on the 50 trim and can expect right around 80-85% peak IDCs. This is with a very rough tune still running extremely rich.

Piggyback systems tend to work well for smaller injectors such as 550s, but the bigger you go the harder it becomes to tune. I tried tuning with large injectors with MAFT alone and had constant problems.

I'd suggest getting compensation AT the ECU with a chip or link to run the larger injectors. You will not be sorry.