Fuel Injectors WHP rating????/ What is the proper size for my application??

3061 Views 11 Replies 3 Participants Last post by turbolarry, Aug 16, 2005

umiami80

Discussion Starter · Aug 15, 2005

Ok, well I may step up into the big leagues and install an AMS GT3076R turbo kit with Buschur FMIC and of course all supporting mods including HKS 272’s.

Anyway here is my dilemma, I want proper fuel control and volume and I plan to retain the stock ECU as I do not wish to use an AEM EMS or anything fancy. Just a flash with a SAFCII for race gas trims. I know a properly tuned flash is just fine for a turbo this size and I have seen Dyno’s by AL of about 435WHP on pump which again is AWESOME.

Now I would like to use the smallest injector possible that will flow what I need to retain stock like drivability and gas mileage. I was thinking Greddy 660’s as I hear they will flow enough for 500WHP and keep about an 80% Injector Duty cycle at 23PSI on pump. I would imagine less on race gas even at 30PSI.

I am wondering if these injectors would be sufficient. I don’t want some oversized volume that would make fuel scaling almost impossible with an overly rich idle and fouled plugs every 2 seconds.

Also is there ANY merit to the claim that ball and plate injectors flow better then traditional Denso style?

Thanks….

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Fourdoor

· #2 · Aug 15, 2005

I personally and running 680's and if it were not for alcohol injection I would be running out of injector. That is running 25 psi on 93 octane with the alcohol injection on a GT35R. Before the alcohol injection I was almost maxing out the injectors to maintain 11.5:1 at 23 psi of boost. If you are planning on having Al tune the car with a dynoflash my view is that he is the best man to ask about what injectors to run. He will know a lot better than any of us what he can get a good idle and good gas milage with

Keith

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umiami80

Discussion Starter · #3 · Aug 15, 2005

Wow ok but I am wondering How much more a GT3076R would FLow Vs. a GT35R at 23PSI. From what I hear the GT3076R is more efficent at that boost level. My guess is that the 660'2 are too small? Other people tell me that they will run fine and you are running alcohol on 25PSI? Why not 30PSI on ALky?

Anyway they Are Greddy 660's which I believe are Denso's, any info on their flow compacity?

Thanks...

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Fourdoor

· #4 · Aug 15, 2005

umiami80 said:
Wow ok but I am wondering How much more a GT3076R would FLow Vs. a GT35R at 23PSI. From what I hear the GT3076R is more efficent at that boost level. My guess is that the 660'2 are too small? Other people tell me that they will run fine and you are running alcohol on 25PSI? Why not 30PSI on ALky?

Anyway they Are Greddy 660's which I believe are Denso's, any info on their flow compacity?

Thanks...

Yup, the GT35R is not even in it's efficiancy range yet at 25 psi. The 3076 should flow more at that boost level than the 35R does. You could probably get away with 660's If you will be running race gas at those boost levels because you will be tunned leaner than you would on pump gas. If you planed on running pump gas at those boost levels I would say go with larger injectors, or go with an adjustable fuel pressure regulator running higher than stock fuel pressure. I am not sure of the actual flow rates for the different types of injectors at "other than stock" fuel pressure.

I am only running 25 psi with the alcohol because I have a bone stock block, including the head bolts. I am making around 460 at the wheels (dynojet numbers) on that boost, and I don't want to run much more than that on the stock block. Yes, some people have run 550+ on the stock block, but this is my daily driver, and in reality I baby it (as much as you can baby a car this powerful)

Keith

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turbolarry

· #5 · Aug 15, 2005

umiami80 said:
I want proper fuel control and volume and I plan to retain the stock ECU as I do not wish to use an AEM EMS or anything fancy. Just a flash with a SAFCII for race gas trims. I know a properly tuned flash is just fine for a turbo this size and I have seen Dyno’s by AL of about 435WHP on pump which again is AWESOME.

Now I would like to use the smallest injector possible that will flow what I need to retain stock like drivability and gas mileage. I was thinking Greddy 660’s as I hear they will flow enough for 500WHP and keep about an 80% Injector Duty cycle at 23PSI on pump. I would imagine less on race gas even at 30PSI.

I am wondering if these injectors would be sufficient. I don’t want some oversized volume that would make fuel scaling almost impossible with an overly rich idle and fouled plugs every 2 seconds.

Also is there ANY merit to the claim that ball and plate injectors flow better then traditional Denso style?

Thanks….

Consider an AFC II without the flash. I have tried tuning an AFC on top of a flash and found it to be a real pain in the ass. It's suspected that timing numbers are set and locked, but no one will come forward and admit it. See MRBlaze's post too;
http://www.socalevo.net/forums/viewtopic.php?p=164201&highlight=#164201

For injector sizing;
http://www.rceng.com/technical.htm#WORKSHEET
Going with 460BHP, .60BSFC, and 83psi fuel pressure, 660's will get it done, but it's up there in IDC. The higher the duty cycle, the less accuate the injectors will be. 720's might be a better choice. Get the STFT's & LTFT's dialed on the AFC, the right range plug and gap, and there will be no drivability issues.

Ball and plate doesn't out flow pintle style, but they have better atomization;
http://www.lightweightmiata.com/sebringmiata/page17.html

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umiami80

Discussion Starter · #6 · Aug 15, 2005

Thanks Again Keith, My only suggestion to you is to install some head bolts, can't go wrong and will hold 40PSI if you ask them too.

From what I know ANY stock 4G63 with ARP bolts can hold 30PSI and in fact as long as their no detonation, it'll hold fine. I also know that 500WHP is just fine but at the limit and could be had on 28PSI, go for it man :thumb:

To turbo Larry, thanks for the info. Better atomization means that the fuel burns easier and more efficently then pintel style? Is this difference noticable or just a bragging right that exhists ONLY on paper??????

Considering ONLY a SAFCII is not really an option as it has no Timing control BUT I intend to get flashed by Al and then add race gas and then lean it out VIA SAFCII for some race gas numbers.

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umiami80

Discussion Starter · #7 · Aug 15, 2005

Oh and turbolarry while I have your attention I would like to ask some tuning questions Via the super AFCII

This weekend is the Evo/STI shootout and I currently run a flash and cams and 272's and all supporting mods. I would like to add some race gas, like 112 octane but I would also like to lean it out, can I just yank it back across the board or do you have any specifi settings I can get away with...

BTW, here is one of my Dyno pulls but not the latest, this is off a turbo trix flash on pump gas.

Here I plan to add race fuel and up the boost a little, what can I do here?

Thanks and any tuning advice would be GREATLY appreciated....

See less See more

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turbolarry

· #8 · Aug 16, 2005 (Edited)

umiami80 said:
To turbo Larry, thanks for the info. Better atomization means that the fuel burns easier and more efficently then pintel style? Is this difference noticable or just a bragging right that exhists ONLY on paper??????

You will not notice the difference until 80%+ IDC.

umiami80 said:
Considering ONLY a SAFCII is not really an option as it has no Timing control BUT I intend to get flashed by Al and then add race gas and then lean it out VIA SAFCII for some race gas numbers.

It may have no timing control, but it has indirect timing manipulation. It's better than no timing anything that the flash provides. That's also the catch when trying to tune the AFC on top of a flash. It's critical to monitor ignition timing advance to detect signs of knock. How can you tell what's really too lean when the timing is locked? How can you get the full power from anything when your timing can only peak to 17*?

umiami80 said:
... can I just yank it back across the board or do you have any specific settings I can get away with...

There are no specific settings for the AFC. Every car is different. To do it right you need a logger to get your car's specific settings.

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umiami80

Discussion Starter · #9 · Aug 16, 2005

How can you tell what's really too lean when the timing is locked? How can you get the full power from anything when your timing can only peak to 17*?

I would just make it 12.5 A/F on race and keep it at that. If you search EvoM under Al's area "DYNOFLASH" he compares a flash to a SAFCII and of course they make the same peak WHP but no where near the same smoothness nor the same midrange. He does tout the usefullness of the Flash/AFC combo. I plan to do all of this on a dyno and tune by wideband. :thumb:

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turbolarry

· #10 · Aug 16, 2005

umiami80 said:
I would just make it 12.5 A/F on race and keep it at that. If you search EvoM under Al's area "DYNOFLASH" he compares a flash to a SAFCII and of course they make the same peak WHP but no where near the same smoothness nor the same midrange. He does tout the usefullness of the Flash/AFC combo. I plan to do all of this on a dyno and tune by wideband. :thumb:

Evom is full of bullshit, 1/2 truths, speculations, and then covered up by the vendors influence and control. I've given up posting there.
Since you are going with the flash and dyno tune, ask them to log timing advance too if they can. If they can't, find someone with a logger, see what your getting, and post your results for pump and the 112 oct.

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umiami80

Discussion Starter · #11 · Aug 16, 2005

Evom is full of bullshit, 1/2 truths, speculations, and then covered up by the vendors influence and control. I've given up posting there.

Tell me about it, I have been banned :thumb: for pointing out many of these items although Al seems to be a respectable Vender and showed two back to back dyno runs.

Since you are going with the flash and dyno tune, ask them to log timing advance too if they can. If they can't, find someone with a logger, see what your getting, and post your results for pump and the 112 oct.

Will do, but for the record what is the noramal/maximum timing advance on and evo with a turbo ugrade and pumpgas????

Thanks.....

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turbolarry

· #12 · Aug 16, 2005

umiami80 said:
Will do, but for the record what is the noramal/maximum timing advance on and evo with a turbo ugrade and pumpgas????

It will be different for every car, but the range the stock ECU can give you; 20-28 degrees.
Bone stock I got a peak of 20* on 91 oct.
http://www.evotuners.net/forums/showthread.php?t=299
AFC (aggressively tuned),720's, cams, stock turbo, TBE, MBC... aggressively tuned mind you on 91 oct; 28* peak timing!
http://www.socalevo.net/forums/viewtopic.php?t=9180&postdays=0&postorder=asc&start=60

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