So I'm in the middle of putting in Cobb 1000cc injectors and there's a detail I'm not sure about. Since Cobb 1000cc injectors are re-branded Injector Dynamics, someone with experience with those might be able to answer my question too.

The Porsche rail has a squarish retaining clip that hold the injector onto the rail, but that also dictate the depth the injector seats into the rail. Hence it also dictates the depth it seats into the manifold.

Note the picture and where the clip engages each injector on the horizontal slat. I lined up the injectors side by side here via the o-rings. The injectors are equally tall when compared by the o-rings. The cobb injector is longer overall.

The stock injector at the right has the slat higher up by ~3mm. Going by this slat, where the square clip engages... This makes the cobb injector seat deeper in the rail. And not as deep on the manifold side. It's not loose, but it doesn't seat as solidly on the manifold side.

Is this how it's meant to seat?

This is supposed to be drop in, so I'm not elongating the rail mounting holes to shorten the mount height. I assume this is also correct?

 

Yes you are good. A lot of guys noticed this and scratch their heads but it works out fine actually. There are some injectors which are longer and do require a rail spacer but not these. I'll take a look and see if I have a picture handy to send you of one seated. If you look at it from the side the silver ring that says Cobb would be flush with the surface.

 

Are you doing this with the engine in place? If so, do you regret doing it this way?

I'm debating between doing my turbos and injectors sooner, but with the engine in place, or waiting a while until I want to drop cash on other parts too, but will remove the engine.

 

LOL, Sam replied to this thread at the same time I emailed him to check it out. How's that for quick service! Can't recommend him enough as a tuner as he's been holding my hand through this.

I'm doing this out of car. With the amount of stuff I'm address including PM on coolant pipes, spark plugs, injectors, back to 3.8 bar FPR (from 5), all PM for fluids, exhaust, fuel filter, etc... it's the quicker more painless way (with a MaxJax I just installed). Still a ton of labor though. But I can be sure that I have the proper access for detailed work instead of fighting though the hatch.

Some pics for future reference.

Seated. Redline is where the clip/channel are:



Bent turbo support bracket to clear cobb injector with adapter. Red line showes how the bracket originally was straight interfering with injector clip/harness. PITA.

 

Cheers, perfect. That's the picture I was looking for from Dan's engine that was out of the race car a few weeks ago.

 

you can just turn the injector to the side to clear the plug.

 

Yes, I tried that but it still caused more interference than I cared for. Also, the slat does not go all the way around like the stock injector. So the retaining clip does not fit securely unless it is somewhat straight.

Could have done many different things...like hardwire a new plug, which I would have preferred, but I didn't have that on hand. So the bracket got the mod.

The passenger side is even tighter and swiveling won't buy much if any more clearance. So I did the same. Vice and adjustable wrench to massage the bracket. That and trace the brackets original geometry onto some paper so you can work the mounting points back to the right positions without retrying it on motor.

 

Reviving this old thread:

I ran with COBB 1000cc injectors last year and they worked fine, but now that I have my engine out I have been able to better inspect/look at the injector fitment.
Like OP I find it strange how the COBB inejctors are seated in the manifold flange..
I know it seems to work just fine but I am considering lowering the fuel rail 5mm to bring the injectors further down.
Both to get the o-ring down where it really seats well and to get the injector opening down nearer the inlet port.

Anyone did the same?
So changed the fuel rail?
Or carefully made a slat higher up in the plastic injector body?

Or should this be left alone - is it meant to be like this with injector positioned where it is?
The spray pattern is maybe so that this is the optimal position..

 

I believe those are Injector Dynamics injectors yes? Paul Yaw is the owner and posts on FB pretty regularly. He seems to enjoy technical discussions and engineering problems, you might want to just ask hm directly. They may have a FB page too just for the company. COBB likewise is pretty approachable. Seems a fair question to ask!

 

Yes, these COBB injectors are really Injector Dynamics.
Wrote Paul and COBB, will see what recommendations they come back with.

 

I'm doing the 1000s as well. Doing it while the engine is in place. What a pain in my kabooky!!

Does anyone know which cylinders run hotter so we can put the injectors that flow ~1% more in those hole? With stock fuel rails.

I went with the DW, DeatschWerks ones. Great product! They provide battery offset (milliseconds- pressure vs voltage) compensation values which is great.
Does the other companies do that? Did the Cobb ones come with it?

 

The injectors I'm using are OEM Bosch which were sent to Bosch for custom resizing for greater flow. Fit is obviously OEM.

 

Where did you get these from? What was the cost?

 

They came from my tuner as part of his turbo package. He doesn't sell them separately but you may be able to contact Bosch and ask them about resizing your OEMs. I'm not sure what size they are but the nozzle injector ports are visibly larger when you look at the injectors side by side.