Stock fuel system with 2.73 pulley

I am in the process of getting my cobra dyno tuned with a 2.73 upper and I was just wondering on how the fuel pumps would handle it and how much power they are reliable at anything helps thanks.


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I ran a 2.76 upper with the stock fuel system. I’m pretty sure the Eaton won’t surpass the capability of the fuel system.

In my case the MAF pegged before the fuel pumps/injectors maxed out. That was on a 2.80 upper, stock lower.


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I run a 2.76 pulley on my eaton. I have BA2600 MAF. Tuner said my pumps were maxed at 483/517

Same here 2.76 ported no lower pumps were almost maxed out 480/460

I know that alot of tuners would recommend a Boost a pump with the wiring upgrade with an intake and pulley.

On 2 different Cobras, I had a 2.70, 2.76 and 2.93 pulley. The cars also had a JLT intake, mid pipe (1 car had a MRT catted H and the other car has a Magnaflow catted X) and 2.5 inch catback. The MAF was good with all 3 pulleys on both cars but I was hitting 95% and above on both cars on the injector and fuel pump duty cycles. The A/F ratio still held up to 6500 RPMs but the duty cycle worried me (tuner did say not to worry and shift at 6000 RPMs).

Have your tuner datalog your car while dynotuning and you both can make a decision from there.

double post

2.76 on my Cobra, with a K&N FIPK, MRT O/R H, Mac S.S 2.5" Catback, LFP Heat Exchanger.

Was close to maxing out the MAF and Pump. Same as others posted A/F held steady, Dave said I might get a little lean if its really cold. But car is a summer cruiser. 470/480

Fastback said:

2.76 on my Cobra, with a K&N FIPK, MRT O/R H, Mac S.S 2.5" Catback, LFP Heat Exchanger.

Was close to maxing out the MAF and Pump. Same as others posted A/F held steady, Dave said I might get a little lean if its really cold. But car is a summer cruiser. 470/480

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About my MAF, I was at 985 with the 2.93 and 1003 with the 2.70 at 6500 RPMs. The tune set the MAF limit to 1024 AD counts so it was close.

HPLouis said:

About my MAF, I was at 985 with the 2.93 and 1003 with the 2.70 at 6500 RPMs. The tune set the MAF limit to 1024 AD counts so it was close.

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IIRC the 2.8 upper pulley put me right around 1000 MAF counts. I wonder what a completely stock Cobra would max out at? Seems like Ford left some head room in the MAF.

I tuned a buddies car with a stage 4 port, 2.76 upper and 4lb lower and it maxed out the stock pumps. I think he had 60lb injectors too. I want to say with my GT pumps I was mid 70's on FPDC with my eaton set up.

01yellercobra said:

IIRC the 2.8 upper pulley put me right around 1000 MAF counts. I wonder what a completely stock Cobra would max out at? Seems like Ford left some head room in the MAF.

I tuned a buddies car with a stage 4 port, 2.76 upper and 4lb lower and it maxed out the stock pumps. I think he had 60lb injectors too. I want to say with my GT pumps I was mid 70's on FPDC with my eaton set up.

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Stock pulley was 920 at 6000 and 950 at 6500 ( 6500 was past the rev limiter) but that’s with a JLT RAI, Magnaflow catted X pipe and catback.


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HPLouis said:

On 2 different Cobras, I had a 2.70, 2.76 and 2.93 pulley. The cars also had a JLT intake, mid pipe (1 car had a MRT catted H and the other car has a Magnaflow catted X) and 2.5 inch catback. The MAF was good with all 3 pulleys on both cars but I was hitting 95% and above on both cars on the injector and fuel pump duty cycles......Have your tuner datalog your car while dynotuning and you both can make a decision from there.

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Just follow @HPLouis' recommendation because you're going to get varying experiences. Your own experience with maxxing out the factory fuel system may vary from the experiences of most others.

Every car is different. One thing to note is the simple age of these cars now. We are talking a car that is pushing 18-19 years old now. The stock pumps were not that bad when new, but after 17-18 years, they may not be as strong. Neither is the corrugated fuel line in the tank. (Or vacuum lines for that matter.)

Datalogs are the key to knowing what the car is Actually Doing. Each car will be different. Once you get to the point of fuel upgrades, I don't recommend a BAP anymore. These pumps are old and now we are pushing them on an expensive engine.

GT Pumps are an option, but require more voltage and more demand. (Also require a retune). The stock hat only has 1 set of wires for the pumps. With the GT Pumps, you really need dedicated wiring for each pump. Now we are talking a better Fuel Hat. Then you will need to upgrade the wiring to the hat and upgrade to a modded FPDM or go to a Dual FPDM setup so the stock one does not go into Thermal Shutdown. At this point it makes better sense to go with a real return fuel system and upgrade. The benefits outweigh the negatives. Even though they cost a little more $$$, they are still WAY LESS than a new engine! Same goes for a good wideband. A necessity for ANY Forced Induction car in my book.

Also, as far as MAF's. If you are seeing 1000 MAF Counts, that doesn't mean you are safe from pegging it out. All it takes is a colder day and you could easily max it out.

Hope this helps, Kevin