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FFCobra Craftsman
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Discussion Starter #1
I have a FMS 351W (M-6007-A351R, 385 HP/377 Torque, Hydraulic Roller Cam Z303, 9.0 Compression, Aluminum GT40 (Intake 1.94"; Exhaust 1.54") Heads, Single plane Victor Jr Intake, BG Demon 750), TKO 500, 8.8 w/ 3.27's.

I like what the 3.27 will represent as far as drivability (lower noise, better fuel economy), but we will occassionally want the wicked quickness that a higher ratio would offer. To compensate, we're considering the following.

I've never had a NOS system, so I would appreciate hearing from those that have had one. My thinking is that normal driving conditions, I would enjoy the attributes of the 3.27's. Under heavy acceleration (full power), the NOS would kick-in and provide the additional power to compensate for the 3.27's.

I don't want to add a system that is going to abuse my engine, so I was looking at one of the smaller 125HP kits. This would bring me to right about 500HP at full throttle.

Again, I'm not going to use this very often. I'm a pretty tame driver (really). So how hard are these things on an engine?

Thanks,
Paul
 

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Well, I am no expert, but you forgot to mentionone very important engine spec: Your pistons are forged.

And thats a good thing for running Nitrous!
 

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FFCobra Master Craftsman
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I'm still building.

I think I'm going to go with the FMS392 with AFR185 heads.
I also want to add a 150hp shot of NOS.

"Just in case".
 

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One of the three events at Run and Gun is drag racing. In 1999 I was moving into position. The red Cobra that just departed in my lane was less than the 1/8th mile when it pinwheeled wall to wall.

Thinking he blew an engine and oil/antifreeze was on the track I declined staging and backed out headed for my trailer.

Later that day we learned the red one lost control when he hit the NOS button.

Roger
 

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Senior Charter Member
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Funny how all the kids want NOS. Put a 3.55 rear end and you have no need for the NOS.

I have a 351W close in specs to your but I have a 3.73 rear end it there is no need for nitrous. Driveability? I have overdrive, it gets good mileage on the highway. Noise? You can't hear any transmission noise with headers/sidepipes anyway.

I had to add drag radials so that it would stay planted!

Just my opinion...but I'm old school.

JQ


**one of the fastest FFR's period is a normally aspirated 289 that runs consistant 10's!**
 

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My 2 cents - 1 bottle of gas will last you a long long time. After the first drive you will decide that it is enough, test the NOS once and that will be it :D

Sometimes more is too much, not very often, but sometimes ....
 

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if you have no competition driving experience you may want to hold off. i have 550hp 3.73 gears and it pulls harder than any sport bike i have ever
ridden.these cars on the street are deadly with those numbers due to traction. i have not put many miles on mine yet but it will step out at 75miles an hour and with the wheel base you better be on your toes.go 3.73 noise is no issue you would not hear a poorly set up set of gears over the exhaust.
 

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Tell your son to try the car first, then he will pee is pants... ;) I’m building a cobra with my dad too, he’s more financial support and I’m mechanical support (I built, he pays, and we drive, a good deal)

Here my story :

I started my cobra project when I was 19, it took 2 years of planning and 3 years of building,

When I started I wanted a 302 crate from FMS, I ended up buying a 351 (same as you), But Since I was young and stupid back then, I decided that 415 hp wasn't enough (the 351 you pick actually puts out 415 hp and not 385)

So I went on an added a 9 psi supercharger from vortech... now the installation was a PITA it took months, but I end up with about 600 hp in a 2200 lbs car,

One word to describe the car : Insane, (what was I thinking !!!!!!)

I'm running 3:55 and I get no traction if the outside temp is in the 60, (I'm running potenza S03...race tires), If I drop the clutch too hard the car is gone, it’s a the point of not being fun to drive, it’s too powerful for the common mortal, and I don’t even want to think about all the tickets I’ll get with it…

Now I'm 25, and I have a lot of respect for that car because if I'm not careful it's going to kill me, plain and simple. I can’t even imagine what would have happen if I did have this car when I was 19 or 20,

So my advice to you is to try it first then see,

Nick
 

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Senior Member
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You have 375HP and you think you (your son) need more HP on 2250 lbs?

OK, I understand, your son whats to sneek out street racing at night when you are asleep, right?

Bill
 

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Your son wants it.

There's a reason they draft kids and not us old men.


How many miles on the car Paul? Have you even driven it yet without nitrous?
Do you have a lot of experience driving light, high performance, short wheelbase cars?
If not, IHMO you should wait until your skills catch up to what you have now before you even think about creating a car that can bite you real big and so quick.

Naga has a stock 5.0 and 3:55's and I have to be careful even punching him in 3rd gear. First and second gear break away ridiculously easily. I'm a long way away from adding more power.

d.



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these cars even with modest hp will get away from you in a hurry, i can't believe you want to have something that is going to give you a 150 hp instant kick in the rear. you are just asking for trouble or disaster. my $.02
 

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I'm not familiar with the TKO "500", but my TKO has a 3.27 first gear, and 1.98 second gear. I'm running an off-breed 3.31 rear end, which is close to your 3.27.

Given this first gear and rear end ratio, your tires are seeing, in first gear, the equivalent to the old GM Muncie (2.52 first gear - early Corvettes, Camaros, etc.) and a 4.56 rear end! Traction is going to be a problem in first gear, even with 250 HP!

I have a big block, which is very close to 500 HP. Drag radials are an absolute must, and traction can still be a problem in the first three gears.

3.55, or 3.73 gears will make your car a rocket up to 100 mph, provided you get a good set of very sticky tires. If you use something like "Radial TAs", you will spend all your time "up in smoke", not going anywhere very quickly - cool for the teenie-bopper crowd, but a good way to get outrun by say, a Mustang GT... :(

Bottom line? If I were doing your car, with your engine, I would do the 3.73 gears, with the Nitto/BFG drag radials (I run Nittos), and forget the Nitrous at least until you become VERY familiar with the car and its capabilities. You will have a car as quick, or quicker to 100 MPH than anything other than the most exotic cars in the world - and still be able to cruse comfortably on the highway with your overdrive.

Sorry for the rambling. I just want you to enjoy the experience. :D

td
 

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Well here's my 2 cents. I've had NOS on my Cobra for 2 years. I run a ZEX dry kit. I run a very modest setting of 75 HP jets on a 302 putting 305 RWHP. The extra kick in the pants is fun but even with my mild set up the additional 60 RWHP and 90 FPT is enough to just smoke the tires. I don't use it as much as I thought I would. I'd say if you go for it use a self regulating kit like ZEX and also always ensure that your install is done properly. The majority of stories you hear about blown engines, or detonating NOS cylinders are because people didn't understand what they were doing. All can be avoided with some care. You can blow up your engine with any improperly installed power adder.
 

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I say DO IT. First off your motor rated at 385 makes 400HP. You could install 100HP NOS which by any NOS standards is a light hit. It is a good idea to use the MSD Auto Retard (Summit 121-8982 $119) which will instantly remove 4 degrees of timing once the switch is armed. Or you could just take out 2-3 degrees and stay there like my friend did adding 125 to a stock 215HP 302 . Easy install with the retard box though. At $29 you should probably also buy a Fuel Pressure Cut Off which is a sensor that disrupts the NOS system if for some odd reason you drop fuel pressure below your setting (ie: 5.5psi)You can also install a momentary button ( summit HUU 248-3875 $29) on the stick shaft or shifter knob ....good use for the Cobra. You have a great motor for coming off the line, certainly capable of frying the tires, so master that in first and second gear. Then ??? Once in third you always have the 100 shot to "help" you along if you need it. The purpose of the button is to give you that on/off control for the NOS while allowing you to go full throttle in 1st/2nd . It is also a good fail safe for those who may "forget" the switch is armed and stomp it in first. I have 515Hp in a 351W and I am considering the same ...only 75 shot. You may consider the Edelbrock kit(Summit 350-70001) at $389. It offers 50/75/100 and the solenoids can handle 125 if you buy the extra jets. The 50 can give you the feel, then you can raise it.
As far as that photo.. That trunk was not charred but the entire vehicle was. It appears the trunk became an oven after a vehicle fire erupted. Any gas or even air sealed in a bottle will expand under high heat of a full car fire. Am I wrong on that assumption ?

Anyway, there are a few guys running NOS in our area, one is also a 100 shot in a FMS 351W with 3.55 gears. There is also a FMS 392 Stroker with a 100 NOS system. I agree you should fully become familiar with the power you now have....then make the move for more power if you desire as many folks seem to do !
 

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You missed the point where he said "FMS 392 with AFR 185 heads", he's already making 500 HP. The guy I sold the last blue cobra to spun the car after 2 months, took out a wheel, upright and axle when he hit the curb. This car had 460RWHP and a very flat (but very elevated 480ish at the rear wheels) torque curve. The torque production was directly related to the right foot, NOS will not. In a 500HP FFR, I would not hit the NOS until 3rd gear at the track with drag radials minimum.
 

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I would think that all the jug would do for you is allow you to burn through tires faster than you would already.....Unless you run slicks, your just going to make more smoke.....not that thats nessesarily a bad thing. A 351, 3.27's and a 2200 lb car and street tires isnt going to have a problem spinning the tires.
 
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