Larger injectors
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Joined: Sep 2004
Posts: 1,958
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From: Ventura County USA
'06 E55, '05 SLK55, a few others
The only way to know for sure is to change them out and dyno the car while mapping the A/F ratio. HPS had to make 2 injector changes to get my car in the sweet spot. I would imagine the best you could hope for is an educated guess, run it, and adjust from there. Is your fuel pressure correct? Without some mods that would cause this, I would be looking for a problem to fix before trying bigger injectors.
Thread Starter
Member
Joined: Aug 2004
Posts: 174
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From: Boston
E430,S500
OK. Here's the deal.
I was interested in larger injectors to add more fuel for more power. At the moment I am running alittle to lean but not a main concern. I'm currently installing a intake manifold from a E55 along with a better airbox. Once done, my ECU will probably have to be adjusted to compensate the increased air flow. With larger injectors added to the mix, I would imagine better results.
I'm still learning as I experiment, so any technical help is greatly appreciated.
I was interested in larger injectors to add more fuel for more power. At the moment I am running alittle to lean but not a main concern. I'm currently installing a intake manifold from a E55 along with a better airbox. Once done, my ECU will probably have to be adjusted to compensate the increased air flow. With larger injectors added to the mix, I would imagine better results.
I'm still learning as I experiment, so any technical help is greatly appreciated.
MBWorld Fanatic!
Joined: Sep 2004
Posts: 1,958
Likes: 1
From: Ventura County USA
'06 E55, '05 SLK55, a few others
You're probably a little lean because everything is normal. Adding these mods probably won't make you any leaner, the ECU will compensate. Once the mods are done, maybe talk to Powerchip or another ECU tuner to get it running it's best. I doubt that will require bigger injectors.
Senior Member
Joined: May 2003
Posts: 458
Likes: 1
From: Oxford, Pa
03 CLK55
I'm not sure, but I doubt that you'll need larger injectors...
Originally Posted by prof.griff
OK. Here's the deal.
I was interested in larger injectors to add more fuel for more power. At the moment I am running alittle to lean but not a main concern. I'm currently installing a intake manifold from a E55 along with a better airbox. Once done, my ECU will probably have to be adjusted to compensate the increased air flow. With larger injectors added to the mix, I would imagine better results.
I'm still learning as I experiment, so any technical help is greatly appreciated.
I was interested in larger injectors to add more fuel for more power. At the moment I am running alittle to lean but not a main concern. I'm currently installing a intake manifold from a E55 along with a better airbox. Once done, my ECU will probably have to be adjusted to compensate the increased air flow. With larger injectors added to the mix, I would imagine better results.
I'm still learning as I experiment, so any technical help is greatly appreciated.
By the by, I don't know what your level of technical expertise is, and I apologize if I'm telling you things that you already know!
Best regards,
Matt
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Thread Starter
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Joined: Aug 2004
Posts: 174
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From: Boston
E430,S500
I dyno'ed the car a couple of months ago with a A/F reading. I tried to upload it but the file is to big. After speaking to others on this subject, the consensus says, the ECU would be the answer to getting the right A/F maps.
No matter how much I think my expertise is, I don't know it all and still have plenty to learn. Every bit helps.
Thanks.
C.
No matter how much I think my expertise is, I don't know it all and still have plenty to learn. Every bit helps.
Thanks.
C.
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MBWorld Fanatic!
Joined: Jan 2002
Posts: 1,810
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From: SFV, Ca.
W210, W220, W163, W164, C6
Originally Posted by prof.griff
Will larger fuel injectors from an 00-02 E55 or 98-99 C43 fit properly into an
00 E430.
00 E430.
C...with your current HP setup, your E430 injector valves are adequate, only if/when you upgrade to FI (N20, turbo, supercharger) you will then need hi-flow replacements.
Engine fuel injector valve efficiency is commonly referred to as BSFC or Brake Specific Fuel Consumption. Naturally aspirated vehicles are most efficient between .4 to .5 lbs/hp/hr and force induction efficient range are .6 to.75lbs/hp/hr.
Having seen your dyno chart:
300HP x .5 BSFC = 150 lbs of gas
150 lbs/8 injectors = 18.8 lbs/hr or 192cc
To target about 80% injector duty cycle:
18.8 lbs/.8 = 24lbs/hr @ 80% duty cycle
As you can see your still within your OEM 357cc/35lbs range.
If you were to add the HPS supercharger:
444HP x .75 BSFC = 333 lbs of gas
333 lbs/8 injectors = 42 lbs/hr or 429cc
To target about 80% injector duty cycle:
42 lbs/.8 = 53lbs/hr @ 80% duty cycle
This has exceed the E430 OEM limits, the reason being HPS includes upgraded injectors with their Gen II system. However, I strongly feel they should include a fuel pump upgrade as well (W210 E55, Walbro or Aeromotive) rather than a aftermarket FMU devise.
I suspect your leaning out due to your aftermarket software. A cost effective method to add more fuel would be to condition your MAF via piggy back.
Good Luck
Thread Starter
Member
Joined: Aug 2004
Posts: 174
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From: Boston
E430,S500
Rich,
Good looking out with the explanation. Still helping a brother out.
Once I have everything installed, I will dyno with A/F ratio to see what the #'s read. Then proceed to correct anything that's off.
Thanks to all you guys.
Good looking out with the explanation. Still helping a brother out.
Once I have everything installed, I will dyno with A/F ratio to see what the #'s read. Then proceed to correct anything that's off.
Thanks to all you guys.
MBWorld Fanatic!
Joined: Feb 2004
Posts: 5,475
Likes: 5
From: City with Tall buildings!
C43/55,2k11 Volvo S60 T6AWD,2k Audi B5 S4,95 Eagle Talon Tsi AWD 500+awhp
Originally Posted by prof.griff
Rich,
Good looking out with the explanation. Still helping a brother out.
Once I have everything installed, I will dyno with A/F ratio to see what the #'s read. Then proceed to correct anything that's off.
Thanks to all you guys.
Good looking out with the explanation. Still helping a brother out.
Once I have everything installed, I will dyno with A/F ratio to see what the #'s read. Then proceed to correct anything that's off.
Thanks to all you guys.
MBWorld Fanatic!
Joined: Feb 2004
Posts: 5,475
Likes: 5
From: City with Tall buildings!
C43/55,2k11 Volvo S60 T6AWD,2k Audi B5 S4,95 Eagle Talon Tsi AWD 500+awhp
Originally Posted by Dan ****
Anyone have a good source for MB fuel injectors? I need some w a heavier duty cycle.
Daniel
Daniel
