Jax951

On my injector service report:

Before:
34
34
33
34

After:
36
36
36
36

Flow rate it says is in ml - is that milliliters? per second? per minute?

Can anyone tell me if this is normal for stock injectors?

Thanks.

Peckster

I asked that question four or five months ago and got some good responses. Look under injectors here or in the 944 turbo forum.

Jax951

I already looked at that before asking, but I didn't find anything with regards to flow rates measured in ml...?

Danno

Hey Jax951, can you scan and post your injector-flow sheet? I'd like to compare to some others we've got:





Check out these threads on how to convert between injectors flowing at different pressures:
<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=18&t=000683" target="_blank">Topic: stock injectors are 37 pound but what OHM?</a>
<a href="http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic&f=18&t=001206" target="_blank">Topic: Garret Hybrid turbo build for 350RWHP? </a>
<a href="http://www.supras.com/~riemer/sonictech/fuel_injectors/RCtech.html" target="_blank">RC Injector Tech Note</a>

That last link has a formula to convert between cc/min (ml/min) and lb/hr. There are also other measurements of flow you want to get familiar with like gal/hr, gal/mile, ltr/hr, cc/sec, etc...

Peckster

Here's some old stuff on conversion. Good luck!


User # 659

posted 02-21-2002 14:17
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Hmmm - I think something is wrong here. According to your injector cleaning results, your injectors are rated at about 370 cc/min at about 2.9 bar which equals about 35 lb/hr (divide by 10.5). In the above post you stated that they were at 42.9 I believe. I was hoping the first figure was correct, but if not please inform. I know of a guy that made 379 hp to the wheels on the stock injectors - thats why I'm starting to get concerned about all the discrepencies. Is it possible that 944 injectors were different flow rates for different years?
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Posts: 408 | From: Manhattan Beach, California | Registered: Jun 2001 | IP: Logged

Danno
Guru

Rennlist Member

User # 1947


posted 02-21-2002 16:32
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Interesting... I think there's something screwy going on with the injector flow-rates from either Bosch or Porsche here. For example, take a look at at Tony Garcia's test on the same injectors:

<a href="http://www.tonygarcia.org/injectors/stock25bar80percent.jpg" target="_blank">http://www.tonygarcia.org/injectors/stock25bar80percent.jpg</a>

His average flow-rate of 262.8cc/min@36.25psi is completely different from txhedg's rate of 372.0cc/min@43psi. Even if you bump up Tony's injectors to 43psi, the flow-rate would be:
SQRT(43psi/36.25psi)=1.089
1.089 x 262.8cc/min = 286cc/min
286cc/min / 10.5 = 27.3lb/min
So it looks like Tony's injectors would flow 30% less (372cc/286cc) fuel than txhedg's for the same 43psi fuel-pressure. Bizarre...
Now I would tend to believe txhedg's injector-report more because, one, it's a newer run, and two, the HP ratings at the bottom would match the stock power-ratings more closely. At a BSFC of .55, those injectors should be good for 206.1bhp @ 80% duty-cyle.

This is below the stock 951's rating of 217bhp. But what about the TurboS's 247bhp? Don't tell me Porsche's overdriving the injectors as it comes out of the factory? And what about all the other hot-rodded 951s that have 300rwhp? That's 350bhp! Or how about Erick's 379rwhp sample? That's a whopping 446bhp, about double the stock power levels. How can one fuel-injector do this? I suspect there's different flow-rates coming out of the Bosch factory with the same part# here...

You may notice on the report that the same injectors Bosch# 0-280-150-803 were used in both tests... Quite odd...
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Posts: 2735 | From: Santa Barbara, California | Registered: Jul 2001 | IP: Logged

txhedg
User

User # 829

posted 02-21-2002 18:59
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Being engineering math-challenged, I didn't know how to do the cc to lbs calc. Instead I used the Total System 141.71 lbs/hr figure, divided by 4, and came up with about 43 lbs/hr per injector....maybe this was wrong......where's an engineer when I need one????
whats the right way to do it?


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Posts: 155 | From: houston | Registered: Jun 2001 | IP: Logged