[5.0 kid]

Im new to this site and i was wondering what kinda of numbers a 95 5.0 cobra engine will put out with ford racing headers, bbk u/d pulleys, bbk cold air intake, trick flow intake manifold, and a 75mm throttle body. i own a 91 lx convertible and im going to put that engine in because my brother fried my original 5.0

[JohnC]

They were rated at 240hp at the crank, right? I'd just guess about 255-265rwhp?

I have no clue honestly. Strap it on a dyno when you get the motor in and keep us posted on the dyno results.

[Darrell]

Originally Posted by JohnC They were rated at 240hp at the crank, right? I'd just guess about 255-265rwhp? I have no clue honestly. Strap it on a dyno when you get the motor in and keep us posted on the dyno results.

That is probably about right. 255 to 265hp at the flywheel though, not at the wheels. Probably gained 8hp from the pullies, 10hp from the intake, 10 from the headers if they are long tube headers and lost about 3 or 4 from the 75mm throttle body. That puts it right around 264-265hp.

[5.0 kid]

what would yall suggest i put on for a real power boost. ive got about 3500 dollars ive put back for such an occasion haha. ive heard alot about stroker kits and such, then there is always the turbo/supercharger debate.

[Darrell]

Originally Posted by 5.0 kid what would yall suggest i put on for a real power boost. ive got about 3500 dollars ive put back for such an occasion haha. ive heard alot about stroker kits and such, then there is always the turbo/supercharger debate.

A good set of cylinder heads.

[5.0 kid]

sooooo say trick flow twisted wedge heads???? or tha dart aluminum heads?

[Darrell]

Trick Flow, Canfield, AFR, etc.

[Bullitt95]

Originally Posted by JohnC They were rated at 240hp at the crank, right? I'd just guess about 255-265rwhp?

They were indeed rated at 240hp at the crank but some will say that the Cobra should have been rated at 250-255hp crank given that they're putting down about 215-220 at the wheels.
With those mods I'd say you could be right at 265rwhp, and there's no way the 75mm TB will cause a 3-4hp loss (more likely that degree of gain instead).
I suggest you port the existing Cobra GT40 heads / Cobra intake, and swap in a Steeda 19 cam. It'll give you a combo that'll deliver abundant midrange torque and still pull well up to about 5700rpm.

[Darrell]

Originally Posted by Bullitt95 They were indeed rated at 240hp at the crank but some will say that the Cobra should have been rated at 250-255hp crank given that they're putting down about 215-220 at the wheels. With those mods I'd say you could be right at 265rwhp, and there's no way the 75mm TB will cause a 3-4hp loss (more likely that degree of gain instead). I suggest you port the existing Cobra GT40 heads / Cobra intake, and swap in a Steeda 19 cam. It'll give you a combo that'll deliver abundant midrange torque and still pull well up to about 5700rpm.

What is your basis for saying "there's no way the 75mm TB will cause a 3-4hp loss"? Do you have any data to back this up? I've seen large throttle bodies lose horsepower on stock to mild engines. The throttle body is one of the last things you would upgrade on a 5 liter.

[5.0 kid]

tell me more about tha 19 cam and how i would go about
getting one.
oh and the reason for the 75mm T/B
is because the BBK 65mm T/B that was on when
i got tha engine was cracked

[Bullitt95]

Originally Posted by Darrell What is your basis for saying "there's no way the 75mm TB will cause a 3-4hp loss"? Do you have any data to back this up? I've seen large throttle bodies lose horsepower on stock to mild engines. The throttle body is one of the last things you would upgrade on a 5 liter.

True that you don't need to upgrade the TB on a 5.0 until you've done quite a few other mods, but I haven't seen a dyno test that has shown a HP loss by upgrading to a larger TB on even a mild 5.0. Then again, not much of a gain either.
I have a 75mm TB on my own 5.0 and while it didn't alter WOT performance, there was a noticeable improvement in part-throttle response compared to the stock 60mm TB.
I'll agree with your last statement but I would say that if one does decide to upgrade the TB, it would be a waste of money to go to 65mm only to find out later on that you should have got a 70 or 75mm unit. Better to upgrade only once.

[5.0 kid]

do yall think LS6 heads would fit on a 95 cobra engine?

[Darrell]

Originally Posted by Bullitt95 but I haven't seen a dyno test that has shown a HP loss by upgrading to a larger TB on even a mild 5.0.

This is just one example...

[Darrell]

Originally Posted by 5.0 kid do yall think LS6 heads would fit on a 95 cobra engine?

You can't be serious....

[07gtmustang]

Originally Posted by Darrell Originally Posted by 5.0 kid do yall think LS6 heads would fit on a 95 cobra engine? You can't be serious....

+1

[Bullitt95]

Originally Posted by Darrell Originally Posted by Bullitt95 but I haven't seen a dyno test that has shown a HP loss by upgrading to a larger TB on even a mild 5.0. This is just one example...

The difference between all the TBs is so insignificant you're splitting hairs. What it does show is that the stock TB is adequate at that HP level under WOT, but what it doesn't show is how a larger TB can improve part throttle response and that's something you can't measure on the dyno.

[Darrell]

Originally Posted by Bullitt95 The difference between all the TBs is so insignificant you're splitting hairs. What it does show is that the stock TB is adequate at that HP level under WOT, but what it doesn't show is how a larger TB can improve part throttle response and that's something you can't measure on the dyno.

The bigger throttle bodies lost power across the board in that example. A bigger throttle body isn't going to improve response, just like bigger carburetor venturis won't. Its very rare that to find a part that will lose power across the rpm range (especially low end) and improve throttle response. However there could be an improvement in response in the design and quality of a throttle body such as an Accufab model over the factory throttle body.

[5.0 cobra]

those are some nice slips
where did you get those?

i hope your kiddin about tha ls6 heads

[Bullitt95]

Originally Posted by Darrell The bigger throttle bodies lost power across the board in that example. A bigger throttle body isn't going to improve response, just like bigger carburetor venturis won't. Its very rare that to find a part that will lose power across the rpm range (especially low end) and improve throttle response. However there could be an improvement in response in the design and quality of a throttle body such as an Accufab model over the factory throttle body.

The power "loss", where there was one, was less than 2% at worst and the HP/TQ numbers were within 1% over almost the entire rpm range. The difference is statistically insignificant and is within a dyno measurement's margin of error.
Secondly, throttle bodies don't behave like carbs. A carb has to mix fuel with air so if the carb is too big, the airflow velocity falls and the fuel can drop out of suspension, causing a power loss. Throttle bodies only have to regulate airflow into the intake manifold so a bigger TB won't cause power loss. A TB that's too big will, however, cause the vehicle to jerk at small throttle openings if you're crawling in slow traffic, which can be a real PITA if you have to keep riding the clutch pedal to keep things smooth.
I went from the stock 60mm TB to a 75mm unit on my Stang, and I can tell you that part throttle response improved enough for me to feel it by the seat of my pants. I can accelerate at the same rate with a much smaller throttle opening and with less pressure on the gas pedal. You'd have to try it yourself to know what it feels like but if you ask me whether I'd prefer to have the 60mm or the 75mm TB, my answer will definitely be the 75.

[Darrell]

Originally Posted by Bullitt95 The power "loss", where there was one, was less than 2% at worst and the HP/TQ numbers were within 1% over almost the entire rpm range. The difference is statistically insignificant and is within a dyno measurement's margin of error. Secondly, throttle bodies don't behave like carbs. A carb has to mix fuel with air so if the carb is too big, the airflow velocity falls and the fuel can drop out of suspension, causing a power loss. Throttle bodies only have to regulate airflow into the intake manifold so a bigger TB won't cause power loss. A TB that's too big will, however, cause the vehicle to jerk at small throttle openings if you're crawling in slow traffic, which can be a real PITA if you have to keep riding the clutch pedal to keep things smooth. I went from the stock 60mm TB to a 75mm unit on my Stang, and I can tell you that part throttle response improved enough for me to feel it by the seat of my pants. I can accelerate at the same rate with a much smaller throttle opening and with less pressure on the gas pedal. You'd have to try it yourself to know what it feels like but if you ask me whether I'd prefer to have the 60mm or the 75mm TB, my answer will definitely be the 75.

If you want to spend the money on a throttle body on a stock or mild engine, go ahead. After all its your money. The issue has nothing to do with injecting fuel. A bigger carburetor flows more air, not more fuel. A bigger venturi will kill throttle response and power if the engine doesn't require the increased volume. Airflow 101. If you are indeed honestly seeing an increase in throttle response I'd bet it is due to the better design of the throttle body, definitely not the size. I went from a 70mm to a 65mm on my 91GT and had a minimal gain in power across the board but no gain in peak power. At the track the car went over a tenth quicker with the 65mm throttle body. As far as having to try it myself, I've probably swapped out more throttle bodies, intakes, cylinder heads than everyone on this site combined. Like I said, I've seen bigger throttle bodies lose power on a dyno and I'm not the only person either. I've never seen anyone say they've seen power gains on a stock to mild engine by going to a bigger throttle body.