Going larger than 42lb injectors

[BenKey]

Since the other thread is so long, thought I would start a new one.

 

With all the discussion of going to a size above a 42lb injector, I thought I would post, as what I know, has to be done, and where to get the "stuff."

 

I had never seen an injector connector like the ones that come on trucks until I bought one in '99. They are different that a standard EFI connector. The largest injector made, that I'm aware of, that can use that connector is a 42lb Multec II, 8.1L marine injector. Same ones that come with a Radix.

 

Once you break out of those and need to go larger, you will have to change the type of connector on your harness and modify your fuel rail slightly.

 

The two easiest places that I found to get the connectors was here:

Summit

And here:

Speartech

(765)378-4908

 

I went with Speartech. They went ahead and assembled the connectors with the size lead I wanted on there. I asked for one 8" and one 12" lead on each connector. That way I had plenty to work with and when I soldered them in place, the connections were 2-3" apart from each other. Basically, it's just cut, slip on some heat shrink (purchased at Lowes/Home Depot), solder, slide the heat shrink over your connection and heat it. Speartech charged me $40 and had them to me in about 7-8 days. I wasn't in any kind of rush.

 

The next thing is the fuel rail. Basically, one of the larger injectors is 5/8" longer than one of the stubby Multecs or stock injector. I went to Lowes/Home Depot and purchased a very small section of galvinized 1/4" metal tubing. Went to the hardware section and matched thread/diameter of one of the bolts I had removed that hold down the fuel rail and bought some that were exactly 5/8" longer - got lucky. I then cut 6 (I think) 5/8" sections from the tubing to use as spacers. Removed the bolts in my Radix and stock intake (I've done both) that secure the fuel rail, slid in the spacer, and screwed in the longer bolts. Experienced zero clearance issues with the Radix. The stock intake, in order to get the engine cover back on, you'll have to work very slowly at bending the fuel rail (crossover piece) down enough to make that happen.

 

Everything is very easy to do as long as you can operate a soldering iron and solder some wires. This is the route I went. Just thought I'd post my experiences.

[zippy]

very good info, thanx ben.

[Farmtruc]

Thanks for the info, I'm upgrading very soon.

 

I think mototron (i think) is coming out with some 60lber's (same size as multec 2's) through racetronix or something like that. I can't remember the full detials. They are supposed to be out mid this year, at least that's what I heard. I'll give them a call next week,

 

allen

[TurbochargedBerserker]

I did the same thing as Ben, except used aluminum tubing. I also bought one bolt slightly shorter than the rest (can't remember exactly, but believe I got one 35mm and 3 40mm) to accomodate the fuel rail mounts on the driver's side rear. I also did no bending of the over the manifold cross over line, and it works, looks fine.

 

I will see if I can dig up the bolt sizes later tonight. I believe they were 8mm.

[SSLink]

I think mototron (i think) is coming out with some 60lber's (same size as multec 2's) through racetronix or something like that.  I can't remember the full detials.  They are supposed to be out mid this year, at least that's what I heard.  I'll give them a call next week,

allen

<{POST_SNAPBACK}>

 

So there may be some stubby 60's on the way? That might simplify things a bit.

Need fuel!

[zippy]

looking at your mod list i bet you could use more fuel.

[SSLink]

looking at your mod list i bet you could use more fuel.

<{POST_SNAPBACK}>

 

I think you're right. Until your recent testing I honestly just assumed that 42lb. injectors ought to be enough to support the HP level my mods are capable of producing.

 

Now I just hope someone can figure out the best route around the '04 fuel system limitations. Is it just bigger injectors with the regulator turned up a notch? Is the booster really needed with the GSS340 pump supplied with the Radix? Or would the best approach be to backtrack to an '03 setup a la BigTex's suggestion.

[BenKey]

looking at your mod list i bet you could use more fuel.

<{POST_SNAPBACK}>

 

I think you're right. Until your recent testing I honestly just assumed that 42lb. injectors ought to be enough to support the HP level my mods are capable of producing.

 

Now I just hope someone can figure out the best route around the '04 fuel system limitations. Is it just bigger injectors with the regulator turned up a notch? Is the booster really needed with the GSS340 pump supplied with the Radix? Or would the best approach be to backtrack to an '03 setup a la BigTex's suggestion.

<{POST_SNAPBACK}>

Let us know how that works. It would be interesting to see it.

[H2Racer]

I ordered my Speartech pigtails and injectors on Tuesday. On Saturday the Speartech pigtails arrived. Once the injectors arrive I'll do the conversion. If they arrive on Monday or Tuesday then I should have plenty of time to get them ready for the track Friday night.

[BluHawk141]

I believe I have found two things wrong, the spacers should be 5/16" or .3125" long and the bolts should be M6. You should bend the fuel rail to keep the injectors firing at the same angle and you will need to oblong the mounting holes in the fuel rail. I do not remember the length of the bolts as it was 6 monthes ago that I did this.

[BenKey]

I believe I have found two things wrong, the spacers should be 5/16" or .3125" long and the bolts should be M6.  You should bend the fuel rail to keep the injectors firing at the same angle and you will need to oblong the mounting holes in the fuel rail.  I do not remember the length of the bolts as it was 6 monthes ago that I did this.

<{POST_SNAPBACK}>

Did what I posted not work? I posted what I did.

 

A standard injector is nearly 3" long, like 1/32 off. A truck injector is almost exactly 2 and 3/8". So doing the math, the difference is 5/8". You may be right on the bolt, but I never specified which, other than you'll need longer bolts equal to the length of the spacer.

 

The fuel rail does not need to be bent, it's just raising it up a little over a half inch. Nothing else is being done to it. My angles were not altered at all doing it this way. I even checked. What I found was that the 1 or 2 degrees it tries to alter it is straightened out from the injector holes in the intake. In other words, the holes force the angle.

 

You may need to oblong the holes after you bend the rail. Other than that, you don't need to.

 

If you did it the way Parish's friend did it, as posted on his website, that's cool. I didn't.

[SSLink]

A standard injector is nearly 3" long, like 1/32 off.  A truck injector is almost exactly 2 and 3/8".  So doing the math, the difference is 5/8".  You may be right on the bolt, but I never specified which, other than you'll need longer bolts equal to the length of the spacer.

 

The fuel rail does not need to be bent, it's just raising it up a little over a half inch.  Nothing else is being done to it.  My angles were not altered at all doing it this way.  I even checked.  What I found was that the 1 or 2 degrees it tries to alter it is straightened out from the injector holes in the intake.  In other words, the holes force the angle. 

 

You may need to oblong the holes after you bend the rail.  Other than that, you don't need to.

 

If you did it the way Parish's friend did it, as posted on his website, that's cool.  I didn't.

<{POST_SNAPBACK}>

 

BenKey:

 

you think the new stubby 60lbers that are supposed to be available soon are worth waiting for? Should simplify things a bit, although from what I understand the connectors will still need to be changed.

 

I wolder if Allen has any news on these yet.

[BenKey]

BenKey:

 

you think the new stubby 60lbers that are supposed to be available soon are worth waiting for? Should simplify things a bit, although from what I understand the connectors will still need to be changed. 

 

I wolder if Allen has any news on these yet.   

<{POST_SNAPBACK}>

It may simplify things a bit. It depends whether or not the fuel rail will still need to be altered, or not. That may be the only saving difference, because as you stated, the connectors will still need to be changed.

 

You can see them on the racetronix site. Hard to say if they'll require alteration of the fuel rail. A stock injector is 59mm tip to tip. One of those new 60lb shorties is 48mm, which comes to about 3/8" shorter than a stock plug. Hard to say what you would need to do. A tip to tip comparison, although it works pretty good for the longer plugs, may not work for the shorter ones. Maybe the plug doesn't seat as far???? Maybe racetronix would know the answer.

[TurbochargedBerserker]

I'm with Ben. My angle wasn't changed without the bend. I also used 5/8 spacers.

[SSLink]

I ordered my Speartech pigtails and injectors on Tuesday.  On Saturday the Speartech pigtails arrived.  Once the injectors arrive I'll do the conversion.  If they arrive on Monday or Tuesday then I should have plenty of time to get them ready for the track Friday night.

<{POST_SNAPBACK}>

 

H2Racer: any progress on the bigger injectors?

 

Zippy, Farmtruc: any new Radix tuning results with bigger injectors on an '04?

 

Sorry if I've missed anything. Been in a coma with the flu lately...