Questions about fuel setup on '94 Supercharged Cobra

[rustinh1]

Hey guys, I have a few questions about my new setup. But first I want to clear up some possible confusion. This is my brother’s account and we both use it. He has the ‘97 Cobra in the profile. I have a ‘94 Cobra. The questions I have pertain to the ’94 5.0 Cobra.

I recently bought a Powerdyne supercharger kit with BBK Boost Timing Master, Power pipe, T-Rex fuel pump, Bypass, and a “Cobra-calibrated” FMU. The kit is supposed to make 9psi or so. Here are my questions:

1. I plan on replacing the FMU with larger injectors soon, then go to a good dyno shop and get a custom chip-burned tune. What size injectors should I get?

2. Will the T-Rex inline pump be enough or should I get an upgraded in-tank pump?

3. Once I get the new injectors with the T-Rex will I need an Adj. FPR to get the pressure back down to a stock level, i.e. would I be over-running the OEM regulator?

4. And lastly, should I upgrade my MAF? Maybe to a Lightning unit? If so, what would I have to do to get it to work?


Sorry if some of these questions seem dumb, I just want it to be right. I want to hand a bunch of LS1’s their ass:thumbsup:

Thanks a million in advance
-Blake

 

[rustinh1]

Nobody???

 

[fiveo'cobra]

1. 38lb or perhaps 42's. Call Powerdyne and see what they rocommend. Also call your tuner.

2. When pushing boost, you always want to stay safe. Should be ok with just the T-rex, but i'd put in a 255 intank as well.

3. When you're doing as many fuel mods as you are, an AFPR is a must. You need it for tuning and with all the new fuel components, your fuel isn't going to be running stock psi.

4. Are you running a stock meter? If so then yes you deff need to upgrade. If you have an aftermarket one, you might be able to sneak away with it. Take it to the dyno and see if it pegs it. Not sure on the lightning meter. Ask on their forums...

 

[rustinh1]

Ok, so to be safe I will also get an intank pump. I will also get an AFPR. And yes, I am on the stock MAF, which is why I will more than likely also buy a lightning meter. There is a company on eBay selling new FMS lightning MAF with lightning green top 42# injectors, so more than likely I will go for that.

Any recommendations on brand for AFPR, I know aeromotive is good, that is what I used on my AWD Talon...

Thanks for the help, I appreciate it,

Blake

 

[94CobraPace]

#1 - You could probly get away with 36 lb injectors, but to be safe & for future growth, get some 39 lb 03 cobras (need adapter for wires) or 42's.
2 - The T-rex will work, but if it were me, I'd get the 255 in tank (which is what I did)
3 - An aftermarket AFPR is a good idea. Aeoromotives are good.
4 - Yes, get a larger MAF meter, your choice. The lightning kit will need a chip to make it work along with a plug.

I have a 9 lb Powerdyne kit on my Cobra. I'm running the super FMU with the 24 lb injectors with no problems. I have had it on a dyno to make sure everything is safe & it is all good. The kit will not make the 9 lbs, I made 5 psi on the dyno. The kit is made for GT's & the Cobras have better flowing intake & heads is 1 reason you will not see 9 psi. You will have to remove the oil cooler when installing the Powerdyne kit also. I made 345 rwhp & 345 rwtq, no chip just adjusting the timing & FP. I ran 12.9 & 109 at the track. If you are going for more horse power, then get another supercharger than the Powerdyne, it is one of the smallest superchargers out. I went with the Powerdyne because I got a smoking deal on it.
Any other mods to the Cobra?

 

[helluvasnake]

If I were you I would go: 42# injectors and LMAF (http://www.buyfordracing.com/shop/product_info.php?products_id=532), along with a Walbro "High Pressure" Intank fuel pump. As for the FPR, I am still on my stock one. The tuner should be able to work with your Air/ Fuel to make you safe. Go with the 42's cause you WILL keep upgrading and you need the fuel.

 

[rustinh1]

I have a 70mm TB, shorty headers, off-road H uncatted, dumped flowmasters, 3.73's, auburn diff, pro 5.0 shifter, fms clutch, steeda springs, caster/camber plates, and tokico struts.

What will I need to make the new lightning MAF work? Do I splice the new plug into my current harness and then its good to go other than the tune?

Should I run both pumps then too (T-Rex and 255 Walbro HP), since I already have the T-Rex?

Thanks a lot for the replies,

Blake

 

[Diabolic]

You could run a 7" crank pulley off an F150 and a 2.93" charger pulley and get close to 9 PSI of Boost. I would run the 255 intank and the T-Rex pump. I would also run a hobbs switch to the T-Rex inline so it's only on when you are over 2 #'s of boost. Saves wear and tear on the pump and it keeps the noise down(noisy pump). I run this setup with my Powerdyne and it works well. Actually ASP is making me a custom 7.25" crank pulley. I would also recomend 42# injectors. Gives you some roo to grow in case you ever want to swap out to a XB1A head unit.

 

[rustinh1]

I was hoping I could simplify it a bit and run just the HP 255, since I will be running a max of like 6psi... I could always throw the T-Rex on later when I upgrade.

1. Shouldn't that push enough fuel volume itself?


2. And does the lightning MAF just splice into my factory harness without problems or is there something to it?

 

[rustinh1]

So I was doing some reading, and my kit is the one that makes 9psi. It is designed for Cobras. It shows a different part number for the 94-95 GT Kit... The 9 psi kit originally comes with an intank pump, which I am guessing is a 255 unit. It doesn't use an inline pump, so I should be ok with just the 255, right, and not using the T-Rex? (I will also pick up the LMAF, 42# inj, and Aermotive FPR)

 

[raven69david]

There are 2 types of 255lph pumps: standard 255lph and high-pressure 255lph. I am currently using the standard 255lph and i'm doing fine. No threat or fear of fuel starvation. Just use the 255 pump and leave the T-rex alone. That's designed to go along with your stock fuel pump which i believe is either 90 or 110lph. (forgot)

Regarding Aeromotive, a while back the talk about Aeromotive was that they seemed to leak quite a bit. After asking for alternatives, everyone was in agreement that Kirban was the way to go, so that's what i purchased. No problems in 2 years. That's not to say that something may go wrong with it later on, but the talk about Aeromotive pumps was that they leaked early in their lifetime. Who knows, just heard about it and decided to not take a chance and just go with the Kirban unit.

 

[rustinh1]

I bought the 255 high pressure pump, so if you are fine on the regular 255 I should definately not have a problem leaving the T-Rex out.

Is it true that the aeromotive regulators leak? I never had a problem with the one in the Talon, but if they leak I will just go ahead and get the Kirban one.

Thanks,
Blake