Cobra injectors(blue giants) need help
05-28-2008, 04:45 PM
#1
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Cobra injectors(blue giants) need help About to do a cam in my car, and a friend of mine got me a set of blue giants for free(woot woot). I know I have to get the EV1 to EV6 swap connectors to make them work, but I've read a couple of times that these injectors aren't ideal for LS1's due to the spray pattern, should I sell these and just get some green tops or something similar or should I go ahead and use these. Basically I'm wanting to hear from someone with some experience with these, if you guys are having problems or they're working great. THANKS!!!!
-Josh
-Josh
05-30-2008, 11:37 AM
#4
I would like to know the exact cone angle of the Blue Giant 39lbers before they get condemned. The 2008 LS7, LS3 and L76 has a 13 degree cone angle and the 2004 LS1/LS2 injectors have a 15 degree cone angle. 5 O motorsports states the following:
42lb Green Giants say they have a split cone.
42lb Green Tops straight stream
39lb Blue Giants have a "highly efficient fuel injector that incorporates a wide-cone fuel delivery. Use in engines with single- and multi-intake valves".
We need input from an injector specialist. A Bosch engineer would be the best source. I can get the GM data but not Fords.
42lb Green Giants say they have a split cone.
42lb Green Tops straight stream
39lb Blue Giants have a "highly efficient fuel injector that incorporates a wide-cone fuel delivery. Use in engines with single- and multi-intake valves".
We need input from an injector specialist. A Bosch engineer would be the best source. I can get the GM data but not Fords.
06-01-2008, 11:07 PM
#6
I would like to know the exact cone angle of the Blue Giant 39lbers before they get condemned. The 2008 LS7, LS3 and L76 has a 13 degree cone angle and the 2004 LS1/LS2 injectors have a 15 degree cone angle. 5 O motorsports states the following:
42lb Green Giants say they have a split cone.
42lb Green Tops straight stream
39lb Blue Giants have a "highly efficient fuel injector that incorporates a wide-cone fuel delivery. Use in engines with single- and multi-intake valves".
We need input from an injector specialist. A Bosch engineer would be the best source. I can get the GM data but not Fords.
42lb Green Giants say they have a split cone.
42lb Green Tops straight stream
39lb Blue Giants have a "highly efficient fuel injector that incorporates a wide-cone fuel delivery. Use in engines with single- and multi-intake valves".
We need input from an injector specialist. A Bosch engineer would be the best source. I can get the GM data but not Fords.
I've seen these on an injector flow bench in action and the spray pattern doesn't look like it would work very well at all for a single intake valve engine. The spray pattern is like a wide 'V'. On an engine with a wide intake port and injector location up near the top of the runner they may work, but on an LS with the tall and narrow ports they are not optimum.
I'm not saying they won't work in an LS engine, just they aren't a good choice of injector for these engines.
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06-09-2008, 02:42 PM
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well........since i'm not really getting a straight answer on this i went ahead and bought a set of GTP injectors(36Lbers) b/c i was worried that these wouldnt work,thanks for the help though guys
06-09-2008, 02:49 PM
#13
No they don't. They are USCAR, not minitimer and require adapters on an LS1.
The question isn't if they will 'work', but rather if the wide "V" spray pattern is optimum for a narrow port single intake valve head. Comparing the spray pattern of these and FMS green tops, they are NO WHERE near comparable. From a visual perspective, the spray pattern is two wide to correctly atomize fuel in a narrow LS1 port without hitting the outside port walls first. Dropping all the fuel out of suspension because of an obstruction early in the intake cycle is counter productive and only complicates an already complicated tuning process.
To each his own, use them if you like.
Originally Posted by autosay97
Believe me, the 39's work flawlessly in single intake valve motors...I have seen them in use with multiple single valve applications including ls1's.
To each his own, use them if you like.
06-09-2008, 03:02 PM
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The question isn't if they will 'work', but rather if the wide "V" spray pattern is optimum for a narrow port single intake valve head. Comparing the spray pattern of these and FMS green tops, they are NO WHERE near comparable. From a visual perspective, the spray pattern is two wide to correctly atomize fuel in a narrow LS1 port without hitting the outside port walls first. Dropping all the fuel out of suspension because of an obstruction early in the intake cycle is counter productive and only complicates an already complicated tuning process.
To each his own, use them if you like.
To each his own, use them if you like.
Your not going to have an 11 to 1 a/f @ 3k today and 14 to 1 @ 3k the next with the same tune/atmos conditions.
Like you said though, to each his own.
06-09-2008, 08:00 PM
#16
I understand your concern when you see them on a flow bench, only other thing to take into consideration the fact that the injectors aren't spraying into a standing volume of air. They are spraying into a flowing airstream which will close the "wide" spray pattern up a significant bit, especially at WOT. These injectors have worked flawlessly in engines with much smaller ports than the ls1's. On to the tuning issues, have you ever tuned a megasquirt "batch fire" system? It actually sprays certain injector in the batch onto a closed intake valve...Lets say theoretically they do spray and hit the walls, its still going to do it everytime and therefore be proportional to rpm day in and day out.
Your not going to have an 11 to 1 a/f @ 3k today and 14 to 1 @ 3k the next with the same tune/atmos conditions.
Like you said though, to each his own.
Your not going to have an 11 to 1 a/f @ 3k today and 14 to 1 @ 3k the next with the same tune/atmos conditions.
Like you said though, to each his own.
I've never tuned a batch fire system, but I would bet they have specific fueling parameters with CLEAR direction about how they work to help optimize a tune.
Spraying fuel on the back of the intake valve is a much better place than the port wall. The intake valve gets hot, no revelation there, and spraying on the back helps to reduce puddling by evaporation.
Why not use an injector that is better suited for an application rather than try to fix the issues related to using the wrong injector? I don't know about you, but I would rather be driving around a road course than cussing at log files and wondering why I can't figure out a transitional fueling issue.
