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Discussion Starter #1
My engine is going to be making 340-360HP. This will put me at about 87-93% :king: capacity for 24lb injectors. Is it worth the expense of upgrading to 30lb injectors?

I have a Vortech MAF, so it's about $40 for the tube and $279 for Accel injectors, so $320. Accel injectors don't have the best reviews and FRPP doesn't make 30lb injectors anymore :shakehead. Bosch ev6 injectors are about $400. I can think of better ways to spend $320-440 if my 24lb injectors are sufficient.


I recently bought a 155lph fuel pump to handle the 24-30lb injectors and HP I will be making. However, not much has changed with my setup and I'm surprised how fast the car was before considering I was running a stock pump. How is it that I was able to run a 13.1 with a 2.0 60' (poor traction) and trap 105.4 MPH in the 1/4 mi while being so fuel starved? Where's Scooby? :rofl:
 

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What's the full combo? 340-360 seems high for a basic bolt-on car. I run 24's in my car (302, E cam, ported GT40 irons, Edelbrock intake, 75mm TB, full exhaust, and 175 shot with no issues.
 

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I'm in the same range and upgraded my FMS 24's to TFS 30's last fall. They look just like the Accel injectors. Not enough mileage on my car since it went into winter storage last fall, but I didn't notice any ill effects with my C&L and 30# tube after I switched.
 

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What's the rest of your combo? the combo in my Thunderbird (see sig) has 24lb injectors, stock replacement Motorcraft FPR, and a Walbro 155lph pump. Traps around 100mph in the 1/4 mile at a 3700lb+ race weight. I haven't gotten any lean codes so I assume it's ok. Then again I could be totally wrong...
 

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Discussion Starter #5
Combo with those numbers:

Gt-40x heads, e303 Cam, Typhoon intake, 70mm TB, 73mm Mass Air, K&N, 1-5/8 to 3" long tubes, catless x-pipe, flowtech terminator mufflers, flowmaster tailpipes, 3.71:1 gears, TKO-600, aluminum driveshaft, 3190lb race weight.

Changes:

155 lph pump, Edelbrock Performer lower ported and matched to typhoon upper, BBK fuel pressure regulator, pullies, 3G, exhaust combo with ground clearance and the same or slightly better power. New race weight 3100-3140.

I still don't know how the 88lph pump handled that.
 

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Discussion Starter #6
340-360 is reasonable for engine HP, which is all that matters to an injector. Engine design efficiency matters, but is pretty consistent for our engines in good condition.
 

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Have you had it at the track? What has it trapped (e.t., mph)? You can get a good estimate of horsepower from a 1/4 mile run.
 

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which is why I went with 30 over 24 for my combo. I'm right around 350-360 crank hp
 

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Discussion Starter #10
I can't find good 30lb injectors at a decent price though. FRPP 24lb injectors are only $200. I have read too many bad things about Accel and the TFS ones are supposedly made by Accel. Why did ford have to stop making 30lb injectors?

The injectors I had seemed to be in bad shape, one was a little bent at the tip from removing the pintle cap. I ordered FRPP 24lb injectors.

Hopefully they can handle the occasional 87-93% duty cycle.
 

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Where have you read bad things about Accel/TFS injectors?

The old yellow colored units didn't review well, but I haven't found any negative posts about the newer stainless steel body design. I also noticed a set of like new 30's in the Corral classifieds for $220.
 

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Discussion Starter #12
It seems the Chevy guys don't like them and the new Bosch 3 style injectors atomize the fuel better. I would rather have a ford injector, for $78 less, not have to replace the MAF, and probably never exceed its limitations without a power adder or new/rebuilt lower end.

Are Accel Fuel-Injectors any good? They seem to be the most affordable ($240 - $390) for set of 8. - Corvette Forum

Accel 26lb Fuel injectors any Good? - CamaroZ28.Com Message Board

Accel Fuel Injectors - LS1TECH

Are accel injectors any good? - LS1LT1 Forum : LT1, LS1, Camaro, Firebird, Trans Am, Engine Tech Forums
 

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My Thunderbird is making around the same power as your car. Get the 155lph pump in the tank and roll with it. If you get a deal on some good 30lb injectors snap them up and run them.
 

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I've been thinking about the 24lb vs 30lb injector debate recently as the engine in my Thunderbird is in that 340-360HP at the flywheel range. With the 24lb injectors the car has now it doesn't throw a code 86 (adaptive limit reached) so I assume the 24lb injectors are enough. I don't expect the car would run any better/faster if I switched to 30lb injectors and if your car isn't throwing a code 86 it probably wouldn't benefit from 30lb injectors either. I could be totally wrong but it seems that in my case (and probably yours as well) 24lb injectors are enough. I'm running a stock replacement Motorcraft FPR as well (39psi non adjustable) for what its worth.
 

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If you're getting the car tuned, you could even run 42's or 60's. Buy what you can get a good deal on.

I have the red top, 30lb. injectors in mine.
 

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I think at this point I'm better off just picking up a Lightning MAF and 30lb injectors when I get the car tuned. I'm guessing the 24lb injectors and calibrated MAF are fine for now. Doing some calculations at ~345hp flywheel 24lb injectors are at about a 90-95% duty cycle at 39psi. I'm in the okish range. For now.
 

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I've been thinking about the 24lb vs 30lb injector debate recently as the engine in my Thunderbird is in that 340-360HP at the flywheel range. With the 24lb injectors the car has now it doesn't throw a code 86 (adaptive limit reached) so I assume the 24lb injectors are enough. I don't expect the car would run any better/faster if I switched to 30lb injectors and if your car isn't throwing a code 86 it probably wouldn't benefit from 30lb injectors either. I could be totally wrong but it seems that in my case (and probably yours as well) 24lb injectors are enough. I'm running a stock replacement Motorcraft FPR as well (39psi non adjustable) for what its worth.

Anything "adaptive" isn't relevant in open loop (when you are putting the injectors to good use)...and EEC-IV isn't checking your A/F ratio @ WOT.

Running a Walbro 255, I've run 24lb injectors @ 41psi base fuel pressure and had enough for AFR-165s and about the same cam. Probably could have used 30s for my combo, but 24s did it with no issue.

I spend the extra money on a 255lph pump and a wet kit over the 155 instead of the injectors...24s should be more than enough
 

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Just some food for though. I know a guy who has a Thunderbird similar to mine (TW170 heads, stock HO cam, GT40 intake) who has a quarter horse. With his combo and 24lb injectors (stock fuel pressure, 39psi) he was hitting 95% duty cycle at 5500rpm. He's since upgraded to 30lb injectors. I've got a bit more cam and intake than him so I'm probably around there at WOT as well.....
 

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Just some food for though. I know a guy who has a Thunderbird similar to mine (TW170 heads, stock HO cam, GT40 intake) who has a quarter horse. With his combo and 24lb injectors (stock fuel pressure, 39psi) he was hitting 95% duty cycle at 5500rpm. He's since upgraded to 30lb injectors. I've got a bit more cam and intake than him so I'm probably around there at WOT as well.....

Totally believable. My 30's show 80% or round about I think.
 

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Anything "adaptive" isn't relevant in open loop (when you are putting the injectors to good use)...and EEC-IV isn't checking your A/F ratio @ WOT.

Running a Walbro 255, I've run 24lb injectors @ 41psi base fuel pressure and had enough for AFR-165s and about the same cam. Probably could have used 30s for my combo, but 24s did it with no issue.

I spend the extra money on a 255lph pump and a wet kit over the 155 instead of the injectors...24s should be more than enough
Ford EEC adaptive learning takes light load short term fuel tables and adjusts the long term fuel tables used when the vehicle is at WOT. If just teset there isnt a problem, but cruise a car for a while and then go beat on it in anger... and there could be lots of ratteling... followed with oiston pieces shooting out tsil pipes
 
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