Another for the books: Accufab TB/plenum dyno

trinity_gt · Jun 5, 2004

Dyno'd my latest mod today, the Accufab plenum and 70-mm TB setup. This is on a near-stock 02 GT (K&N FIPK-II and March UDPs were only other mods on the car.)

"Before" was 242.3/285.9 and "after" was 247.4/290.6 (rwHP/ft-lbs) for peak gains of 5.1HP and 4.7 ft-lbs. Gains were across the board but after 4100 is when the biggest gains were seen.

These are lower than I'd hoped for and lower than what the ads led me to believe. Still, I'm not uphappy because I know the mods will pay later as more breathing mods are added, especially on the exhaust side.

FWIW, a Dodge SRT-4 was there ahead of me. His only mod was a Mopar "Stage 1" PCM & injector upgrade. He put down 242/260; the Stage 1 mod gave him 10HP over his bone stock run of 230/250...

MustangLife · Jun 5, 2004

$400 for parts and $100 for dyno time for 5 hp. Doesn't seem worth it to me at all.

Josh

Go HoTO! · Jun 5, 2004

Hey, don't loose sleep over this as your before may have been a few ponies high with the other mods. Could have been weather.

CottonBurnerz · Jun 5, 2004

I dont' care much about the peak hp.. what about the curve? any chance that you can post the before vs after graph?

007 · Jun 5, 2004

MustangLife said:
$400 for parts and $100 for dyno time for 5 hp. Doesn't seem worth it to me at all.

Josh

Thats why I'm not buying the plenum+TB stuff yet. Fairly pricey for small gains. The lower intakes should be interesting though (when they finally come out). LTs and Cams better gains for the cash, assuming you can do the install. I guess tuning after cams makes it cost a fair chunk more though.

007 · Jun 5, 2004

trinity_gt said:
Dyno'd my latest mod today, the Accufab plenum and 70-mm TB setup. This is on a near-stock 02 GT (K&N FIPK-II and March UDPs were only other mods on the car.)

"Before" was 242.3/285.9 and "after" was 247.4/290.6 (rwHP/ft-lbs) for peak gains of 5.1HP and 4.7 ft-lbs. Gains were across the board but after 4100 is when the biggest gains were seen.

These are lower than I'd hoped for and lower than what the ads led me to believe. Still, I'm not uphappy because I know the mods will pay later as more breathing mods are added, especially on the exhaust side.

FWIW, a Dodge SRT-4 was there ahead of me. His only mod was a Mopar "Stage 1" PCM & injector upgrade. He put down 242/260; the Stage 1 mod gave him 10HP over his bone stock run of 230/250...

I was wondering... why didnt you get gears or mid-pipe before the plenum stuff?

trinity_gt · Jun 6, 2004

I'll be scanning the plots on Monday (hopefully) and will update my site next week.

Torque was up about 5ftlbs across the board from the look of things, right from 2500.

I have, shall we say, "spousal issues" with doing much more than top-side bolt-ons at this point. Besides, gears don't make any more power...they'd be an "optimization" later. As for the exhaust, that stuff is next on my list though it may not happen for a while. Aside from pulling off the piggyback March crank pulley, going with a Steeda damper and adding a TA, I think I'm done on the "top" side of the engine and the exhaust will recieve attention next (unless someone comes out with a sure-thing 20HP intake manifold...)

I'm a bit torn at this stage though. I definitely am not spending the bux on a cat back for the 4HP and added noise & potential drone it'd add. I've not yet seen proof that a catted H- or X-pipe is worth more than a couple of HP too (someone please prove me wrong: what gains might I realistically expect with a catted MRT H or Magnaflow X right now, with the stock manifolds and stock cat-back?) LTs seem to be the way to go but there's cost, installation and other issues for me with them since the midpipe will need changing at the same time. This will probably be a next-spring thing, having saved the bux over the winter.

007 · Jun 6, 2004

trinity_gt said:
I'll be scanning the plots on Monday (hopefully) and will update my site next week.

Torque was up about 5ftlbs across the board from the look of things, right from 2500.

I have, shall we say, "spousal issues" with doing much more than top-side bolt-ons at this point. Besides, gears don't make any more power...they'd be an "optimization" later. As for the exhaust, that stuff is next on my list though it may not happen for a while. Aside from pulling off the piggyback March crank pulley, going with a Steeda damper and adding a TA, I think I'm done on the "top" side of the engine and the exhaust will recieve attention next (unless someone comes out with a sure-thing 20HP intake manifold...)

I'm a bit torn at this stage though. I definitely am not spending the bux on a cat back for the 4HP and added noise & potential drone it'd add. I've not yet seen proof that a catted H- or X-pipe is worth more than a couple of HP too (someone please prove me wrong: what gains might I realistically expect with a catted MRT H or Magnaflow X right now, with the stock manifolds and stock cat-back?) LTs seem to be the way to go but there's cost, installation and other issues for me with them since the midpipe will need changing at the same time. This will probably be a next-spring thing, having saved the bux over the winter.

I've seen plenty of evidence showing that the mid pipe gives good gains - try searching the forums.

Also the comment that gears do not make any more power is not necessarily true. Its not about how much power your engine makes, but the power you are putting to the ground. Gears will make your car faster because the keep the engine in the higher rev range where it already makes more power, thus putting more to the wheels. They are a very effective "bolt-on" modification.

JonJon · Jun 6, 2004

trinity_gt said:
I've not yet seen proof that a catted H- or X-pipe is worth more than a couple of HP too (someone please prove me wrong: what gains might I realistically expect with a catted MRT H or Magnaflow X right now, with the stock manifolds and stock cat-back?)

You should've done a mid pipe first, it's much more noticable than the intake crap. I actually felt a difference after my mid pipe, I felt nothing from pullies, intake plenum, tb, maf, cat back.

trinity_gt · Jun 6, 2004

007 said:
I've seen plenty of evidence showing that the mid pipe gives good gains - try searching the forums.

Also the comment that gears do not make any more power is not necessarily true. Its not about how much power your engine makes, but the power you are putting to the ground. Gears will make your car faster because the keep the engine in the higher rev range where it already makes more power, thus putting more to the wheels.

I can do that with the transmission. If I'm on the highway and want to pass someone I don't simply floor it in 5th and wait...I'll go down to 4th or perhaps 3rd and get the engine into the meat of the power band. At best gears might eliminate the need to downshift. This isn't to say I won't get 'em though; 3.73s are on my short list of things to do. I do like the idea of the car being more sprightly around town, even if it means more RPM for a given speed and/or less speed in a given gear. I was impressed with the difference in feel between a Mach 1 (3.55s) at low RPM and a GT (3.27) at low RPM where a bit more torque multiplication would be ideal for the 4.6. But it's not giving more power and that's important to me.

As for midpipes, yeah, more research is in order I guess. JonJon has the pipe and the cat-back and makes 8 more HP than I do. Again, seems like a mod that costs a ton and doesn't add a whole, whole lot. SHM has the Magnaflow cat-back for $479.00 and a catted X-pipe for $595.00. $USD1074.00 seems like alot to spend for maybe 8HP...

007 · Jun 6, 2004

trinity_gt said:
I can do that with the transmission. If I'm on the highway and want to pass someone I don't simply floor it in 5th and wait...I'll go down to 4th or perhaps 3rd and get the engine into the meat of the power band. At best gears might eliminate the need to downshift. This isn't to say I won't get 'em though; 3.73s are on my short list of things to do. I do like the idea of the car being more sprightly around town, even if it means more RPM for a given speed and/or less speed in a given gear. I was impressed with the difference in feel between a Mach 1 (3.55s) at low RPM and a GT (3.27) at low RPM where a bit more torque multiplication would be ideal for the 4.6. But it's not giving more power and that's important to me.

As for midpipes, yeah, more research is in order I guess. JonJon has the pipe and the cat-back and makes 8 more HP than I do. Again, seems like a mod that costs a ton and doesn't add a whole, whole lot. SHM has the Magnaflow cat-back for $479.00 and a catted X-pipe for $595.00. $USD1074.00 seems like alot to spend for maybe 8HP...

Dude you are nuts if you dont think gears help. You cant "do that with the transmission" - your gears are longer. 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. Stock gears can never keep you in the power band the same as closer gears will. They are an absolutely proven mod that WILL make your car much faster than the bolt ons you are talking about. You should get them before any other bolt ons. But what do I know...

Buy exhaust from stangnet. Magnaflow jacked up the prices but I believe stangnet are doing the rebate thing. I'm lucky I guess... I paid 320 for the cat-back and 350 for the mid-pipe.

3ponyshow · Jun 6, 2004

trinity_gt said:
I have, shall we say, "spousal issues" with doing much more than top-side bolt-ons at this point.

HAHA! That sounds familiar! I'm glad someone else has the same issue.

Anyway, You'll probably see more gains when you add the modified exhaust. I did it in a different order tha you, but I got 6 hp from the cat back and another 4 from the mid pipe. 10 total. But the best bang for the buck are the gears. No you don't add hp, but you'll be amazed at how it wakes up what you already have. I have 3.73's 'cause I'm going s/c (after the inevitable divorce it will cause) but if I wasn't I'd go 4.10's. Seriously. For the $, there is NO comparison. IMHO

twogts4us · Jun 6, 2004

3ponyshow said:
But the best bang for the buck are the gears. No you don't add hp, but you'll be amazed at how it wakes up what you already have. I have 3.73's 'cause I'm going s/c (after the inevitable divorce it will cause) but if I wasn't I'd go 4.10's. Seriously. For the $, there is NO comparison. IMHO

Agreed 100% You will wonder why you didn't do it sooner. No, it doesn't add power, it just makes the car feel about 700 lbs lighter!

JonJon · Jun 6, 2004

trinity_gt said:
As for midpipes, yeah, more research is in order I guess. JonJon has the pipe and the cat-back and makes 8 more HP than I do. Again, seems like a mod that costs a ton and doesn't add a whole, whole lot. SHM has the Magnaflow cat-back for $479.00 and a catted X-pipe for $595.00. $USD1074.00 seems like alot to spend for maybe 8HP...

Paid $370 shipped for my catted X from PartShopper (8 months ago) and it was much more worth it than the tb/plenum. I wouldn't get them if I went back.

trinity_gt · Jun 7, 2004

007 said:
Dude you are nuts if you dont think gears help.

Well, it's not that I don't think they will "help", it's just that they won't ultimately give me more power at the wheels. I like the idea of additional torque multiplication to help lift the car out of the hole, sure. A 3.55-geared Mach 1 I test drove certainly "felt" a bit better at low RPM.

You cant "do that with the transmission" - your gears are longer. 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. Stock gears can never keep you in the power band the same as closer gears will.

Hmm. Not sure I agree with this. The amount of RPM the engine drops between shifts is not related to the axle gear ratio. It's dependent upon the ratios in the trans only. If I wind the engine to 5500RPM in 1st (3.38:1) and shift into 2nd (2.00:1), the engine will drop to about 3250RPM. Think about it: at 5500 in 1st, the driveshaft RPM is 1627, give or take. Assuming the car doesn't speed or slow appreciably during the half-second it takes to shift, the driveshaft RPM will still be 1627. The difference is that the gear ratio in the trans, 2.00:1, forces the engine to slow to get this same driveshaft speed. The only outward difference between 3.27 gears and 3.73s is that the axle RPM at that shift goes from 497 down to 436 and the vehicle speed drops from 37.7 to 33.1 MPH respectively. So the 3.73 car gets to its 33 MPH terminus faster than the 3.27 car gets to its 37 MPH one but also needs to shift earlier and isn't going as fast at each shift.

Still, the engine RPM drop between shifts is unaffected.

They are an absolutely proven mod that WILL make your car much faster than the bolt ons you are talking about. You should get them before any other bolt ons. But what do I know...

It will make the car feel faster, might help dig it out of the hole but it won't be appreciably faster through the quarter mile. Any gains are not due to power but to shortened 60-fts.

I will be going to 3.73s in the not too distant future for precisely these reasons but I'd really like the car to be making a satisfying 260-ish rwHP and gears will not get me there.

Buy exhaust from stangnet. Magnaflow jacked up the prices but I believe stangnet are doing the rebate thing. I'm lucky I guess... I paid 320 for the cat-back and 350 for the mid-pipe.

Cool. Thanks, I'll look into it.

Jackie Chan · Jun 7, 2004

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

cap42 · Jun 7, 2004

Trin I put down 240rwhp 281 rwtq with only the Dr. Gas mid pipe and flowmaster catback for performance mods under the hood is bone stock including the motorcraft paper filter. Not a bad increase for just exhaust work.

Get a good mid pipe and some gears you'll see some good improvements

01GT eibach · Jun 7, 2004

trinity_gt said:
Dyno'd my latest mod today, the Accufab plenum and 70-mm TB setup.

Why the 70mm and not the 75mm TB? I thought that it was optomized for 75mm .... not true?

mike2858 · Jun 7, 2004

you keep stressing that you know you will FEEL faster- the reason that is true is because you WILL BE faster. your horsepower may not change at all-i heard it might actually go down marginally-but there is a reason that the car "feels faster"

and no i dont have gears, yet, but if you look at most of the people in here-especially those who go to the track a lot- they ALL have gears. dont you think there is areason for that?

Dark Knight GT · Jun 7, 2004

There is something I believe everyone is overlooking here. Trinity GT already gained 9.3 rwhp with his K&N FIPK setup. Now, that was a good gain, most definately. He also gained on this dyno run approx. 5rwhp. Now, I personally believe the weather or not so good a tank of gas could of costed him a couple hp but thats only speculation. What we do know is between the K&N FIPK and the Plenum/TB combo, his car is making about 14.3rwhp over stock. Not bad if you ask me considering the rest of his car is pretty much stock. If he were to open his exhuast up a bit, he'de probably see a few more hp numbers out of his intake setup, not to mention the power he'de gain from exhuast work.

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.

Another for the books: Accufab TB/plenum dyno

trinity_gt

MustangLife

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007

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trinity_gt

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I didn't read this.

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Another for the books: Accufab TB/plenum dyno

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