Injector Options 550cc 680cc 700cc

[Crazybobmundo]

So I was looking into buying 550cc injectors to go along with my Lex AFM but I was looking through Driftmotion and found that they sell 700cc Injectors for $410!

I was concidering the following...

Supramanias Factory Style 550cc
or
DM Siemens 550cc

Then like I said I found those 700cc...even the Siemens 680cc are about the same price.

My real question is what would happen if I get an injector that is that big?
The reason why I consider them is because I dont like to buy things twice and if lets say I decide to put more money into the car then I dont want to upgrade the upgrades.

Even 680s are fine with me...but the 700s are cheaper.

Any one have advice?

Thank you

 

[rayall01]

The 550's are a perfect match for the Lex AFM, as the both equate to a 25% increase. 25% for the airflow, and 25% for the fuel flow. Going bigger with the injectors is possible, but requires more tuning to get it working right. That's why most people going Lex, stay with the 550's.

 

[tbcmorris]

You need something to tune with to run an injector that big.
The lex/550 trick is a way around tuning (should still fine tweak with at least a safa) this is because the afm allows about 25% more air and the 550s are about 25 % bigger.
Stick with the 550s




*edit* beat to the punch

 

[Crazybobmundo]

So even though those 700cc injectors are cheaper than the Suprasport Factory style 550cc's Im going to end up spending more with the 700cc anyway because of the equipment I will need to even run them...

Damn it I wish I could just get those. Oh Well, thanks you two.

 

[tekdeus]

550's aren't so bad for power later on either. I was able to get quite a bit more fuel out of them with more fuel pressure via an aftermarket fuel regulator. With these injectors and a $350 AEM methanol kit adding a little more fuel I can push 24+ psi without any fuel cut (pulling fuel with an SAFC)

 

[grimreaper]

my 550's give me quite a bit more fuel then i need with my current setup. scaling something bigger with a piggy back is going to get hairy if your not on top of things.

besides, if you need something bigger later, there is always someone willing to buyt the 550's for a decent price.

 

[Flateric]

On my old 7M setup I had sent my HKS 550cc injectors of to a local shop (Reg Reimers's RCTS) for cleaning, checking etc and every single one of them flowed at 620cc. A substantial bit more then what they are rated for, I got big power for many years and many smiles per mile outa them.

Not sure if this is the norm or not for injectors or if HKS under-rates theirs or what. I had thought that most injectors are in fact made by one manufacturor (denso? perhaps) and just re-badged for all the different companies selling them. I'm sure there is more then one company making them, but I believe not as many as you may think.

Are HKS under-rated or is this the norm?

What I'm getting at though is......I really enjoyed my 550's and they never really disappointed me or allowed my setup to run into the lean side of thing a danger to my engine.

It is my understanding however with additional fuel management that you can run less boost to achieve the same result that smaller injector running higher boost would.

 

[MacDaddy_J_420]

I am running the lex afm/550 combo it ends up being pretty evenly matched roughly 25% more air and fuel. This allows for less tuning which is the way to go unless you have the $$$ to spend on a better tuning system. I am also a believer of buy for you needs at the moment and then upgrade later if you want to go bigger. I have the PTE 550's, but suprasport.com has it where you can send your 440's and they can modify them to flow 550cc or more. Biggest plus is not having to change injector clips which means keeping the wiring harness uncut. Here is the link http://www.suprasport.com/SupraSport-Custom-Injectors_p_5466.html

 

[frontierguy25]

Get some 550's or some 580's(PTE) if you are still on the lex afm until you get rid of it to with a standalone that can control the bigger injectors. The 550's will get you about 450rwhp. I'm hoping to get the 580's just for a little extra measure, if not, I'll just have to deal with the 450rwhp.

It is much easier to tune with the 550's or 580's

 

[grimreaper]

^ says the guy that melted a piston with craptastic 680's ( i know the circumstance were different, just busting balls!)

you are going to have to pull a LOT of fuel with 680+ injectors with out a larger turbo and other mods. Pulling fuel = ++ timing = BOOM! on a stock ecu. Your line of thought has been thought out before. With out a standalone bigger is NOT better

 

[Crazybobmundo]

Yeah then I guess Ill go with 550's. I dont see me doing 400hp or anywhere near there. Those arent my plans right now..I just have to get it running at this point

But this is good info.
I know of one guy that used to deal with DSM's and he claimed they swap parts between owners (those engines apparently blow up all the time) and someone that hasnt touched their engine or electronics picks up injectors from a different owner and uses them...

I hate this guy by the way, hes a know it all. But I still much rather hear it from you guys who have the same car I do .

 

[grimreaper]

dsm = -2 cylinders = -2 injectors. The general "idea" of modding and tuning a car MIGHT work from car to car, But it never fully works out that way. Ask your bud what he would do with a 7m if it idled at 4-5 psi of oil pressure... motors are just to different to take advice (on a detailed level) from someone that has not delt with your setup.

< see my time spent online? 95&#37; is searching and learning. The mkIII is old, its been done so many ways you couldnt imagine. mkIII to a DSM = A goat to a unicorn

 

[Crazybobmundo]

Yeah I agree.

Like I tried to explain I didnt just go and buy parts according to 1 guys opinion or advice. I understand theres limited amount of things we can do to our cars that may work with others.

Thats what I like about this forum though, I get pretty straight answers and not just from one guy but many of you guys who, like you said Grimreaper have done things that others would never have imagined to do themselves. Theres many point of views.

Thanks a bunch you guys.

I may at this point just use my stockers and make a better decision of what I want...