Stock 3.2 injector flow rate?

thrown_hammer · 06-21-2005, 08:23 AM

What is it? Also what would the next step up be? Are the injectors interchangeable with other makes or aftermarket suppliers?

RickM · RickM's Garage

Shawn,

This thread may shed some light on injectro capabilities Fuel Injectors for High HP Turbo . You can go with other injectors but I think they're typically made by Bosch.

BTW, according to Todd from Protomotive, the 3.2 injectors are capable of up to high 400s.

thrown_hammer · 06-21-2005, 09:38 AM

Quote:

Originally posted by RickM
Shawn,

This thread may shed some light on injectro capabilities Fuel Injectors for High HP Turbo . You can go with other injectors but I think they're typically made by Bosch.

BTW, according to Todd from Protomotive, the 3.2 injectors are capable of up to high 400s.

Then I guess the stock ones will work. Thanks!

fastpat · 06-21-2005, 10:20 AM

I did a bit of research on this subject about 6 weeks ago, Shawn.

I found that the 911 Carrera injectors are low impedence, similar in many ways to those on the 86-88 BMW M5 units. Like most electro-mechanical injectors, they function best at no more than an 80% duty cycle. Based on the fuel flow needs of your engine, now or later, you can calculate the duty cycle your injectors will function at based on the fuel they can supply over time.

Fortunately, Porsche chose to size injectors and operate them at 2.5bar, which is below that typical on many installations. BMW uses 3.0bar on most of their FI systems, and you can bump up the fuel pressure to 3.0bar without exceeding the physical limits of the 3.2 injector at all. This higher pressure will give you a bit of head room with the stock injectors should you build an engine that needs more flow.

If you need more info, such as exact flow rates, let me know.

thrown_hammer · 06-21-2005, 11:40 AM

Thanks for the info Pat. SO the stock injectors can handle 300-320 HP no problem.........

Rot 911 · 06-21-2005, 11:49 AM

Quote:

Originally posted by thrown_hammer
Thanks for the info Pat. SO the stock injectors can handle 300-320 HP no problem.........

This sounds like a 3.2 turbo question!

thrown_hammer · 06-21-2005, 12:21 PM

Quote:

Originally posted by Kurt V
This sounds like a 3.2 turbo question!

Kurt,
It was a statement.....Besides I asked for a friend of mine. He wanted to know, not me.

Mr Beau · 10-01-2005, 04:45 PM

Anyone know what the #/hr or cc/min rating of the factory 3.2L injectors are? I see discussions on how much power they can support, but not their actual flow rating.

Thanks.

Lukesportsman · 10-02-2005, 08:28 AM

I've got a question out for this exact question. Turbo question? Yes. I know that Protomotive raises the fuel pressure to get their hp rating which within reason is very acceptable. If you raise the fuel pressure too far their pattern goes out the window and looks like a fuel hose. My brother was a injector engineer for Honda and I've seen the flow pictures. Chrysler injectors flow the most, but have a really ugly pattern that alone could influence hp and efficiency.

Remember, though, hp ratings for NA and forced induction in respect to injectors are not compatible due to fuel requirements differences. A given injector or pump will be rated higher for NA applications than forced induction.

Would this be for the wife's targa, Shawn?

89911 · 10-02-2005, 09:43 AM

Along the injector questions, is there any performance gain to have your injectors "matched" to flow rate? Or do the come fairly evenly matched?

TOO RUF · TOO RUF's Garage

stock injectors Part#0280 150 158 448 060
22 lbs, 230cc 41.5 duty
fuel pressure for a 300HP turbo must use rising rate fuel pressure regulator witha starting pressure of 4.7bar or 68lbs.

Lukesportsman · 10-02-2005, 05:16 PM

I'm amazed at Protomotive's optimism of either its safe HP or their actual hp produced. They must be willing to push the envelope past .80 duty cycle due to the fact that most turbo engines will not stay there long. When I punch in 400hp to the formula I'm getting a required 430cc/42lb injector. Protomotive uses a 3.82 fuel pressure raito so I do not know where their rail pressure ends up. I'm still concerned with the flow pattern if it gets too high.

Back to Shawn's question: The formula would indicate a needed injector of 28lbs/300 cc for a naturally aspirated 320 hp at the factor 3bar/42lb fuel pressure.

What are we missing here if people are getting so much higher hp levels out of stock injectors?

Is this a confirmed answer? low impedence injectors! most easily obtained Bosh OEM injectors like Ford 42lb injectors are high impedence injectors. They do make convertors for low impedence injectors on high level drivers. Do they make conversions the other way?

Quicksilver · 10-03-2005, 05:39 AM

I think the reason that it is so easy to exceed the duty cycle is it is impossible to stay at that horsepower rating for more then a short blast. You would quickly run out of road unless you have a place were you can exceed 160 for a while. You can't really even do that on the track.

Lukesportsman · 10-03-2005, 05:50 PM

Wayne,

I'm not sure that is completely true. AFR is going to be related to rpm, load, and throttle plate position not necessarily the gear your using. Sure, I guess that would limit the time your exceeding the limit by an upshift.

Pat, do you anything you can add to this discussion? Any insight?