★ Russianred's Turbo Build Thread! ★ *UPDATED 4/15* ★

[Russianred]

Re: Russianred's Turbo Build Thread! *UPDATED 2/7/11*

Most recent food for discussion is as follows:

Is there a difference between the OBD1 and OBD2 injectors in terms of maximum (ceiling) size? Like for example is there a maximum size injector that each system supports, or can I get injectors in any size I choose and run them both for OBD1 and OBD2 systems? I know OBD1 requires the resistor box which I have installed, but would OBD1 limit injector capabilities in the long run, or can I run just as large injectors on OBD1 as on OBD2 system, as long as everything is hooked up correctly?

This is concern for the future. Right now I am running 480cc Denso RX7 injectors, but I know that in the future I will need to upgrade, and if OBD1 does limit injector size then I would consider going back to OBD2 with a standalone. Hope my thought process makes sense.

 

[BadgerType]

Re: Russianred's Turbo Build Thread! *UPDATED 2/7/11*

you speak in circles


obd-i and ii have no bearing on injectors. there are two general kinds of injectors, peak and hold and saturated. we use Saturated as does the 00 lude

1992-'96 Prelude Non-VTEC Peak and Hold 240cc
1992-'96 Prelude VTEC Peak and Hold 345cc
1997-up Prelude VTEC H22 Saturated 280cc


There are two basic types of injectors that work on Honda and acura cars. How they operate are totally different. Let's take a look.

Peak and Hold:

Peak/hold injectors are low impedence, usually in the 1-4 ohm range. When the ecu calls for fuel to be injected, it sends out voltage via the wire clips until a certain current level is reached (the peak part) (varies by injector size, company). For the duration of 1 pulse width, that current is slightly reduced and held (the hold part).

Advantages of this design:
•minimizes the injectors "on" time, resulting in faster response
Disadvantages of this design:
•increases coil heat, which can lead to failure over time

--------------------------------------------------------------------------------


Saturated:

Saturated injectors are generally higher impedence than peak and hold, running in about the 10-15 ohms range. Unlike peak/hold, a saturated injector remains "on" for the entire pulse width.

Advantages of this design:
•reduces heat
Disadvantages of this design:
•slower response time
•can't handel large CC or lb/hr styles due to limitations in its speed.

--------------------------------------------------------------------------------


So, which should I choose?

There are a ton of factors involved in this.
•First, power level. If you're going big, there simply won't be a saturated injector that will support your power level. The largest common saturated injecotrs on the market are 550cc, with 440cc being a common "cap" in saturated size. Most boosted people run peak/hold setups for not only their availibilty, but also their ease of upgrading later on if so desired. simply swap the injectors. no need to re-wire again.
•How is your car wired? most obd0 civics and some preludes are wired for peak/hold and have a resisitor box already. No point in changing to a saturated. Obd1+2 civics, and most other honda/acura cars after 1992 are all saturated and are not wired with resisitor boxes. Again, if there is an injector availble in your power range for flow of your car's design type, there's little sense to change.
•Price. DSM eclipse/talon 450cc peak and hold injectors fit honda rails and with just a minor modification plug right in. best of all, these can be had for about $50-75 a set of 4 instead of $350+ for a set of aftermarket injectors. Add a $25 resistor box from an obd0 civic/crx, wire it up, and you're good to go in you're saturated car.
in a later article, we will cover the injector resistor box install procedure.

copied and pasted from HS cause i was too lazy

 

[Russianred]

Re: Russianred's Turbo Build Thread! *UPDATED 2/7/11*



Not sure if I was talking in circles, I think I just wasn't sure of the big picture and proposed a scenario which ended up being false per your provided info, so I got my answer. The information you provided has helped me much oh great Badger.

The conclusions I have made from your information are exactly what I was looking for and are as follows:

I will be using the peak-and-hold (low impedance) injectors with resistor box for my build.. why? Well because that's how I ALREADY have it all wired up. The clutch point you made Badger is that you said I can get larger injectors if I go the peak-and-hold route, which is the answer I needed.


Synopsis:

Glad OBD1 accommodates larger injector sizes in the long run, for high power applications, whereas OBD2 is limited by ~550cc saturated style components.

Moving right along

 

[akoutmos]

Re: Russianred's Turbo Build Thread! *UPDATED 2/7/11*

Just as a side note on the sizings on saturated injectors. You can get them fairly large. For example, i am running RC engineering 750cc injectors. I have not seen past that in terms of output, but with a good fuel pump, 750cc injectors are capable for a comfortable 450hp. Remember injector output is very dependent on fuel pressure.

 

[BadgerType]

Re: Russianred's Turbo Build Thread! *UPDATED 2/7/11*

normally, peak and hold large injectors are cheaper, with dsm guys running bigger turbos they needed to swap out to a biiger set. so the demand for the peak and hold are greater than saturated

 

[hotaccord243]

Re: Russianred's Turbo Build Thread! *UPDATED 2/7/11*

Now, I just want to throw something out there. Have you guys seen the new(er) injector dynamics (Bosch modified) saturated high impedance injectors?
They cost a little bit more than others but they are not too bad. They are available in 725, 850, 1000, 1600, and 2000cc sizes.

Click here
These babies are just plain bada**. No resistor box required at all. A lot of other injectors when you start reaching within their nominal flow rate or beyond you begin to see their spray pattern start to dissipate and become un-even. These ID injectors will hold their spray pattern well beyond their nominal flow rate and then some. They hold their flow rate at low and high pulse widths to allow for smooth idle and extremely well high power. They are some of the next best thing as far as injectors go.

Also, due to the "noise" that the walbro fuel pumps make, one suggestion i would have and have seen done is put a walbro 255 in your fuel tank to replace you OEM one, and then install a Bosch in-line fuel pump for the extra pressure in the engine bay. I have heard these things are dead quiet and provide much better power and pressure. A friend of mine has this setup and you cannot hear the priming of the fuel pump or anything.

He also has a set of the ID1000cc saturated injectors and is running them beyond the nominal range for them and not seeing any sign of struggle of the injector trying to keep up or rough spray pattern.

I think this is something that i'm heading towards myself: trying to go with a better injector that will hold its spray pattern throughout its range, getting rid of the resistor box, and the noise from the fuel pump, cause it's just annoying. I would say go slightly larger than what you think for many different factors (running E85 in the future, more power down the road, etc.).

Just my $.02 as far as injectors.

 

[Russianred]

Re: Russianred's Turbo Build Thread! *UPDATED 2/7/11*

^ See that's what I'm talking about, an unorthodox variant. So Devin, what would the drawbacks be to using these type of injectors minus the more expensive price?

My Overview:

ID OBD2 saturated high cc injectors

Pros:
No resistor box required for OBD1 application?
Removal of noise and resistor box.
Longer held stable flow pattern.

Cons:
Price
Availability

Is the resistor-less option on ID injectors specific to that company? Or are all high cc saturated injectors made to work without a resistor box on any OBD system?


Have you heard of Deatschwerks Injectors? My friend works there and the 480cc Densos in my car now, were actually cleaned, flowmatched and tested by him before I put them in the Accord. I know they got some bada$$ injectors there, but don't know if they have the high cc saturated ones.. I'm sure they do.

Exactly my train of thought for this discussion, so that there is room to improve and run a more aggressive setup.

 

[akoutmos]

Re: Russianred's Turbo Build Thread! *UPDATED 2/7/11*

Injector Dynamics have some sick injectors (i completely forgot about these little suckers ). T1 Race Development sells them. They are super expensive though. Especially some you go past the 1L mark. A lot of supra people use them cause of the high flow rates and good drive-ability you can get with them.

You will not need a resister box for the ID saturated injectors or any saturated injectors for that matter. So long is the injectors them selves have a high resistance(like 12 ohms) no resister box will be needed. The ID injectors are around 11.8 ohms while the RC engineering injectors run at around 12.5 ohms.

 

[hotaccord243]

Re: Russianred's Turbo Build Thread! *UPDATED 2/7/11*

Like akoutmos said, its the resistance on the injector itself that determines if you need a resistor box or not not the OBDI or OBDII. Your going to be running some sort of program, so it doesn't matter what you use as regards to injectors. You can always program them to work.

The ID injectors are disgustingly awesome. If you have the money by far do it. They key to those is the driveability with them at low and high flow rates and they keep their spray pattern even beyond their optimal range. The drawbacks for the ID injectors i don't see any besides price to tell you the truth.

The denso injectors aren't that bad at all either. I don't know about their availability in flow rates for them though. They are all great injectors to be honest, Precision, RC, Denso, are all great injectors. I would just make sure that you go slightly bigger so you have room for more or room to play with E85/race/pump gas.

 

[Russianred]

Re: Russianred's Turbo Build Thread! *UPDATED 2/7/11*

These any good?

RC1600cc New set of 4:

Guy's selling them for $300.. Maybe I could even talk him down some.

The seals/grommets I could definitely source myself.