Another for the books: Accufab TB/plenum dyno

scion4LIFE · Jun 7, 2004

AND pullies.

Arnolds97 · Jun 7, 2004

My Mac O/R H provided huge gains. I did however have the 3 per side cats on my 97. I have an Auto and was worried about bottom end torque loss but instead gained. Depending on where you live just find some one that will pass it on an inspection.

It has been at least 10-15hp on the butt-o-meter. It would only turn the tires for 20ft maybe and now it just rips them for about twice that. Mid Pipe used 50.00. Not bad bang for the buck. Gears are also a big performance boost. I have not got them in yet (3.73's for 30.00 used) but have road in others with and the car is transformed. Pulleys, Plenum P&P and K&N CAI did not amount to half the mid pipe changes.

Arnolds97 · Jun 7, 2004

The deal with gears is that you get into your power band much quicker becasue you start out at 300-500 mores rpms off the bottom therefore you are quicker. No horsepower but more efficiency to get you there quicker instead of Salt Flats type starting acceleration.

Pulleys are similar. They reduce parasitic drag by slowing down the accessory drives therefore they unleash the horsepower that is taken away by them. Alternator, water pump, powersteering, air con etc.

007 · Jun 7, 2004

Jackie Chan said:
is this tech or ??? Everyone knows gears dont add rwhp, but the results speak for themselves.

The only person that would EVER say gears arent all that is a guy that doesnt have them

I know man. I'm trying here. But I've given up now. I'm beginning to think anyone with any technical knowledge left has gone to the depot.

StngStr · Jun 7, 2004

4.10 gears got me from a best of 13.69 to a best of 13.43 with the same 60 ft and same shifting.

Gears don't add power, but they make your car faster. You won't drop ET's like that with an intake plenum or pulleys.

Jackie Chan · Jun 7, 2004

StngStr said:
4.10 gears got me from a best of 13.69 to a best of 13.43 with the same 60 ft and same shifting.

Gears don't add power, but they make your car faster. You won't drop ET's like that with an intake plenum or pulleys.

tell me about it

Dark Knight GT · Jun 7, 2004

007 said:
I know man. I'm trying here. But I've given up now. I'm beginning to think anyone with any technical knowledge left has gone to the depot.

Not quite. I'm still here.

NasaGT · Jun 7, 2004

Dark Knight GT said:
Personally, I believe this goes back to the old saying of "there's only so much air you can flow to the motor with the cylinder heads, cams, and displacement being stock".

EDIT: I also seen someone mentioned something about why he used a 70mm throttle body and not a 75mm throttle body. I think I'll point out to you that the key to making power isn't in the throttle body and I personally think there would be no rwhp between a 75mm and 70mm throttle body across the powerband. You "may" see a peak of 1 or 2 extra hp at 6k rpms but no real differences on the powerband.

I beleive this to be the case as well. I think he's getting all the airflow he is going to get until he does exhaust, cams, or headwork.

trinity_gt · Jun 8, 2004

007 said:
I know man. I'm trying here. But I've given up now. I'm beginning to think anyone with any technical knowledge left has gone to the depot.

Sorry, you're not helping alot by saying stuff like "If you run down the track with 3.27s and then with 4.30s, 1st will give a better 60ft, and all following gears are right there in the power band after every shift." (rear gears do not alter where the engine RPM lands after each shift) or "Also the comment that gears do not make any more power is not necessarily true" (actually, it is correct: gears do not make more power). Let me ask you: do you think that when someone writes "I have 250 rwHP and 280 ft-lbs at the wheels" that they actually have 280 ft-lbs at the rear hubs during, say, a 4th gear pull?

Look, I've already stated I know the benefits of gears, whether you want to believe it or not. I've also stated, quite correctly, that gears do not make any more power and that they are more "optimizations", not unlike how UCAs might give you a faster 60-ft despite not adding power. I will go with 3.73s at some point in the future with the full expectation of having to shift sooner and having to live with revving higher on the highway, but also of getting away from a stoplight with a bit more "oomph."

Nasa, and some others, are right: the motor will not get any more air "in" without additional mods, probably on the exhaust side. Cams, perhaps... Head work, unfortunately, is not in the cards. I do think it's valuable for other readers to know that outlandish claims of 10+ HP from the Accufab plenum and 70mm TB on a stock GT (such as is stated in the SHM 4.6L book) are just hype and advertising hokum.

mrvax · Jun 8, 2004

Gears are an essential early mod. Gears will allow a stock Mustang to throw your azz back in the seat.

The Magnaflow exhaust was also a good mod. Get gears first though.

302 coupe · Jun 8, 2004

trinity GT, look at it from this perspective. Lets say the engine makes 300 ft-lbs of torque. For simplicity, lets also say your in 4th gear, it has a 1:1 drive ratio. You also have 3.27 gears in the diff. Torque at the rear wheels can be calculated by multiplying engine torque x trans ratio x rear gear ratio. So, with the 300 ft-lbs, a 1:1 4th gear raio, and 3.27 gear, you get an effective 981 ft-lbs torque acting on the axle. Now, lets change the rear gear to 4.30's. 300 ft-lbs x 1:1 4th gear x 4.30 rear gear gives you 1290 ft-lbs torque acting on the axle. Thats over a 31% increase of torque acting on the rear wheel. So basically, it will make your car 'feel' like you have 31% more torque. That 280 ft-lbs at the rear will act like 367 ft-lbs.

trinity_gt · Jun 8, 2004

302 coupe said:
trinity GT, look at it from this perspective. Lets say the engine makes 300 ft-lbs of torque. For simplicity, lets also say your in 4th gear, it has a 1:1 drive ratio. You also have 3.27 gears in the diff. Torque at the rear wheels can be calculated by multiplying engine torque x trans ratio x rear gear ratio. So, with the 300 ft-lbs, a 1:1 4th gear raio, and 3.27 gear, you get an effective 981 ft-lbs torque acting on the axle. Now, lets change the rear gear to 4.30's. 300 ft-lbs x 1:1 4th gear x 4.30 rear gear gives you 1290 ft-lbs torque acting on the axle. Thats over a 31% increase of torque acting on the rear wheel.

Yep, I know that. Just remember that the wheel RPM drops by a similar percentage meaning that the power you're actually putting down remains, theoretically, the same.

NiteMareGT · Jun 8, 2004

I have a couple of things here.........

1)
GEARS are more easily explained like this. Put a 10 speed bicylcle in 1st, now peddle. Alright, with your same leg power, start that bike off in 5th gear. Get the picture?? This is an almost EXACT example of how gearing works in a vehicles rear end. If you don't think gears make you faster in the 1320, you're seriously mistaken and misinformed! Taller gears helps the engine work more efficiently. Slightly taller gears, such as 3:55's or 3:73's may even net you a higher top end because our cars are somewhat lacking for power in 4th on the open road @ wot, and the slightly taller gears will help it to red-line better in 4th, without it taking 3 miles. Any taller and it's overkill though.
2)
With all the mods you have, which I know aren't insanely significant, I would put you up against an otherwise Stock GT with just some 4.10's and a 5 speed manual, and you'd probably lose by 1 1/2 to 2 cars in the 1/4. Cost?.......around $169.00. How much have you spent not to be as fast as the guy with a stock 5 speed GT with 4.10's? I know of no better way to explain it.

S.D.-Stangman · Jun 8, 2004

Jackie Chan said:
is this tech or ??? Everyone knows gears dont add rwhp, but the results speak for themselves.

The only person that would EVER say gears arent all that is a guy that doesnt have them

I Disagree. I have 3.73's and guess what... they arent all that. I was not impressed with the feel of them at all. I wish I would have saved the money and put it in my supercharger fund. If you are going to do gears, go 410's. Dont fear the gear.

Another for the books: Accufab TB/plenum dyno

scion4LIFE

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I didn't read this.

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Stay thirsty my friends

302 coupe

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