Throttle body & upper plenum . worth it?

fiveoho

15 Year Member
Apr 28, 2005
1,958
16
69
TN
browsing corral and ebay. seeing that tb's and plenums are pretty cheap to buy used, is it worth spending the cash? even buying new stuff isn't all that high. all i have now is full exhaust minus headers, diablosport canned tune and a better flowing air filter. i wouldn't expect much actual whp, but maybe a crisper throttle response and quicker revs?

looking at professional products and c&l stuff based on the price. any idle issues? will they play nice with my tuner?
 
i know gears are the best bang for buck. i had them in my previous mustang but from experience, im very hesitant about having the gears swapped. i enjoy my quiet smooth 3.27s. 4.10s would really wake the car up but theres always that chance they will whine and i CANT STAND THAT. motorsport gears or not, theres still that chance. if i had it done, id have to pay for the ring and pinion, the labor and for a bearing/seal kit. be pretty easy to have several hundred $'s caught up in it . yes, i know - power isnt cheap. just was looking at more budget friendly ideas. and no matter what others say, mileage will suffer some and at $3.20 a gallon, cant sacrifice too much.

if i had a shop remotely close that i fully trusted to do the install, i would be more likely to consider it despite the fuel mileage change.
 
Many years ago my buddy ordered a brand new 1985 Mustang GT. It was over $12,000 then. The car was loaded, 4 speed, 302, T tops... it was a lot of change back then, at least in our world.

I will not forge his words of wisdom.. "If you want to play, you have to pay."
If you want to play you dont order a Fox with an AOD. :nono:
 
Stock heads or cams? No.

Aftermarket heads or cams? Absolutely.

+1. I installed my accufab early on and it made a difference but pretty minor. Even if it is used I wish I would of spent the money on other things before I bought it.

Instead of gears I would make sure you had these mods (in the same dollar range too):
1) Aftermarket shifter
2) Subframe connectors
3) Front brake upgrade (okay a little more expensive but a worthwhile mod)

The best thing for quicker revs is more power- :) Go big if you want to feel a difference
1) FI
2) Cams and/or heads
 
I only noticed a slight difference at wide open throttle in the higher RPM's with my 75mm TB and ported plenum. If you can get 'em cheap, sure... but don't expect much. It will be "in place" for later mods though, that being the bonus.
 
From experience, w/larger TB and Intake, the power to temperature ratio is greater, when the car is sucking warm air compared to stock you are gonna have less power compared to the stock setup, but when the air is cold and dense, that S.O.B. will pull like its a brand new engine. Just one man's opinion.
You would probaly want some 24 pound injectors and a new tune, later down the road.
 
From experience, w/larger TB and Intake, the power to temperature ratio is greater, when the car is sucking warm air compared to stock you are gonna have less power compared to the stock setup, but when the air is cold and dense, that S.O.B. will pull like its a brand new engine. Just one man's opinion.
You would probaly want some 24 pound injectors and a new tune, later down the road.

If the engine is pulling hot air, it's pulling hot air regardless of tb/plenum size. The larger TB/plenum alone won't cause it to move that much more air because you can only fill the cylinders with so much to begin with on a bolt on car.

Tune is a good idea after all the bolt ons are completed, helps everything tie together... but it's not a "must", thankfully... for people with my budget anyway...:D
 
i know gears are the best bang for buck. i had them in my previous mustang but from experience, im very hesitant about having the gears swapped.

Staying with stock gearing is a huge mistake on a mod Mustang though, mate. I saw no change in mileage. I can get 25mpg on the highway!
Had them installed for 125 bucks at Mustang Magic in NY (admittedly that was a long time ago). They are completely silent. Just get them installed by someone experienced.

Your honestly wasting money on the plenum junk. You'll barely be able to tell the difference. Better off spending on wheels, tires or suspension, or just saving for a blower.
 
Staying with stock gearing is a huge mistake on a mod Mustang though, mate. I saw no change in mileage. I can get 25mpg on the highway!
Had them installed for 125 bucks at Mustang Magic in NY (admittedly that was a long time ago). They are completely silent. Just get them installed by someone experienced.

Your honestly wasting money on the plenum junk. You'll barely be able to tell the difference. Better off spending on wheels, tires or suspension, or just saving for a blower.

but if i have them installed and they whine, that would be a huge mistake. mileage will change some because my car will see over 60mph. i cant drive to NY for a gear install :rolleyes:

already got wheels, tires, springs. blower will be over 2k. dont want to spend that on the car, rather put it in the bank. there was an article in 5.0 a few years back where they baselined a stock 2v then added a plenum, tb, exhaust, diablosport, pulleys....seems like something else. the results were not bad , especially given what i can spend for those things buying off ebay or slightly used.


im not arguing that gears will not make a difference. you are completely right that there will be a much better seat in the pants feel. but i fall under murphys law and right now, my stock gears and nice and quiet.
 
If the gears are installed properly then there will be no whine. I have used Explorer 3.73s in my car and at over 160mph there is no whine. Its all in the setup. I paid $300 for install and bought a FRPP master install kit for $94 from Five Star Ford. The solid axle master kit is even cheaper.

As for mileage, dont care what people say. I have installed gears in 9 of my 20 Mustangs and I always lost a couple MPG at higway speeds. My Mark went from 26 MPG to 23.6 when going from 3.27 to 3.73 gears. :shrug:
 
5.0 JULY 07

"nice and easy"


stock 03 5 speed gt : 213/242


+cherry bomb catback (stock midpipe) : 217/251

+accufab 75mm tb+plenum : 233/259

+jlt ram air intake : 237/262

+march pulleys : 242/267

+diablosport : 243/271
 
Staying with stock gearing is a huge mistake on a mod Mustang though, mate. I saw no change in mileage. I can get 25mpg on the highway!
Had them installed for 125 bucks at Mustang Magic in NY (admittedly that was a long time ago). They are completely silent. Just get them installed by someone experienced.

Your honestly wasting money on the plenum junk. You'll barely be able to tell the difference. Better off spending on wheels, tires or suspension, or just saving for a blower.

i ran low 13s na on just bolt-ons stock gears, running low 11s on street tires on stock gears. gears are a myth in my book. btw i have many many many many... posts on this dyno sheets, track runs, videos ect. plenum will pick up on avg. 7-10rwhp and .3/2-3mph at the track. We also did test with my bolt-on non-pi 98 gt, we did 3 back to back test with the stock 2.73 gears ran on avg 14.3, installed 3.73 gears on avg ran 14.5 (both 2.0 60ft). My best times in that car were done with 2.73. 13.8@98mph. If anyone else can show me more than .3-5 tenths JUST from gears, no dr, slicks or better tires, then just maybe gears are better than added something that gives you REAL rwhp.:eek:
 
Gears aren't a myth.

A turbo car will run better with a numerically lower gear in many instances because there's more load placed against the engine for the turbo to spool from.

As far as your times after the swap, don't know what to tell ya. I dropped 2/10ths in my 1/8th times alone by going to 4.10's. It definitely leaves harder with a higher gear than it did with the 3.27's, and it gets into the power band quicker in any gear in comparison to stock gears with IMO is a pretty big benefit

They work, but the results you see depend on how the rest of your car is set up, your driving habits, etc. Nothing wrong with choosing to stick with stock gears. I kept my 3.27's because when they were pulled, they showed very little wear. Like I said in another thread, my goal is single turbo for my GT and those gears would be damn near perfect. On an N/A or S/C car, it's hard to argue against a higher gear, though.
 
5.0 JULY 07

"nice and easy"


stock 03 5 speed gt : 213/242


+cherry bomb catback (stock midpipe) : 217/251

+accufab 75mm tb+plenum : 233/259

+jlt ram air intake : 237/262

+march pulleys : 242/267

+diablosport : 243/271

213rwhp/242rwtq for a stock PI GT???? WOW, talk about a factory terd