Things To Look For

[newedgejay]

hi, can someone tell me if my car sounds like a stock mustang? ive had it just over a month. its a 99 gt automatic with a racing tune on it. i run 93 gas in it. it has no cats with twin turbo thrush exhaust. it can do a quarter of a mile in twelve seconds and my 0-60 is a low7, about 7.20. what im asking is if this sounds like its all stock. ive had various people tell me it could be built. the previous owner had no idea about anything about the car. any help is appriciated!

 

[Mattstang04]

Can you show us actual time slips from the track to verify the ETs? We would be better able to tell you about the status of your vehicle with time slips.

 

[madspeed]

engine bay pics would also help. It is an automatic 99 GT. Running 12's it either had a blower, nitrous or other major mods done to it

 

[newedgejay]

here are some pictures of the engine bay, the closer one is when it was dirty when i first got it.

 

[trombonedemon]

Stock and add two seconds to that quater mile.

 

[vertigasen]

Wow, I forgot how ugly the stock engine bay was.....

 

[madspeed]

sorry grasshopper, but that car will struggle to get a time quicker than 15.0

 

[newedgejay]

alright, if i ever do, and i hopefully will in the few coming weeks, take it to the track, ill SURELY post my time.

 

[Mattstang04]

Wow, I forgot how ugly the stock engine bay was.....

True that. I had completely forgotten what the stock CC plates look like. The things like a time capsule.

OP, get those times. I hope we didn't burst your bubble. If you want to run 12s it can be done and it can be fun getting there.

 

[TeamCaffeineGT]

An easy way to tell if the engine has been modified extensively is to look at the color of the injectors. Your pics show that you have the stock orange top 19lb injectors.

You can use the following formulas to determine injector size needed and horsepower limits of the injector:
Injector size = (HP x BSFC) / (number in injectors x duty cycle)
Horsepower limit = (Injector size x number of cylinders x duty cycle) / BSFC)

A couple definitions:
BSFC - Brake Specific Fuel Consumtion - "The BSFC is how much fuel is used per horsepower per hour. For a naturally aspirated engine, that figure falls between .45 - .5 BSFC."
Duty Cycle % - The percentage of time the injector is open during one cycle of the engine.

With the last formula, we can see that 19lb injectors, with 8 cylinders at a 100% duty cycle rate and a .5 BSFC looks like this:
(19*8*1)/.5 = 304 hp.

In other words, at full throttle you can only be making a theoretical max of 304 hp.

Max HP @ 100% Duty Cycle. Common Ford Injector Ratings:
Orange Top - 19lb - 304hp (Stock 4.6 GTs)
Blue Top - 24lb - 384hp (Pre-Terminator Cobras)
Red Top - 30lb - 480hp (Ford Racing Performance Only)
Green Top - 42lb - 672hp (Terminator Cobra and Lightning)

There are scenarios where the injector could be pushed past its operating limit, running a higher fuel pressure for example. I have never heard of anyone doing this and it is not recommended and it would be much easier to swap out the injectors.