Why do I have such low torque output, and how can I fix it?

astronut1885

Founding Member

Jan 31, 2002

1,899

4

39

Assonet, MA

Jun 8, 2004

#1

• Jun 8, 2004

• #1

Hey guys. I ran the dyno a month ago, and I laid down 281 ft/lbs of torque at the wheels. I had a pretty bad tune at the time, so I know the numbers are a little lower than what they are now that the tune is good, but they're still low over all. I've ridden in stangs with less work than mine and they pulled harder than mine all day long. When I mash the throttle it seems my car takes a little too long so wind up, and it doesn't really pull me into the seat. I know part of that is because I have stiff progressive rate springs, so the weight transfer is minimal and the rear end doesn't "squat", but it's still not enough. My main parts are:
GT40P heads, E303 cam, Explorer intake, 1.72 roller rockers, FRPP "P" shorty headers, 2 1/2" Mac Prochamber, 2 1/2" Mac Flowpath catback, U/D pullies, MAC cold air intake, 1" phenolic spacer on the intake manifold, stock MAF and TB , 3.73s, aluminum d/s, stock T5, MSD 6AL, blaster coil and 8.5mm wires, Timing 10*, 93 octane gas, Autolite 764s gapped to .45", Crane AFPR set to 41 psi,

 

bmorrisj

Member

Sep 26, 2003

449

0

17

Buena Park, CA

Jun 8, 2004

#2

• Jun 8, 2004

• #2

set your timing to 12~14*, get a bigget maf >73mm, and bigger TB/EGR 65mm/70mm....

 

astronut1885

Founding Member

Jan 31, 2002

1,899

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Assonet, MA

Jun 8, 2004

#3

• Jun 8, 2004

• #3

Yeah, the timing has to be fixed. I thought it was set to 15*, but the markings on my harmonic balancer were from -5 up to 15, not 0 to 20 like I thought, so it's 5* behind the ball. I realized this when under the car the other day. My friend has a timing light, and I'll be seeing him today, hopefully I can reset it then.

 

J

Js5ohLX

Member

Apr 5, 2004

287

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16

Ohio

Jun 8, 2004

#4

• Jun 8, 2004

• #4

Are you using the stock maf?

 

DMAN302

My mom says thanks for the pearl necklace.

Nov 8, 2003

2,120

2

59

windsor, Canada

Jun 8, 2004

#5

• Jun 8, 2004

• #5

Sounds like the car is angry about fuel curve..Should consider maybe upgrading MAF to like a pro-m 75 calibrated to 24's and drop pressure to 38-39Psi. You also didn't mention if you have cycle tested the injectors or done compression test for bottom end. Could be so many different things..I know after going to new intake and dropping down to 65mm T/b from 70mm for some ungodly reason I had to drop my timing back from 13 to10 deg and drop fuel pressure from 41 to 37..difference was night and day car pulled like I had added 2 extra cylinders.

 

astronut1885

Founding Member

Jan 31, 2002

1,899

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39

Assonet, MA

Jun 8, 2004

#6

• Jun 8, 2004

• #6

My compression is 175 on all 8 cyls. Timing will be addressed today, and I have a 75mm chrome bullet MAF sitting in my back seat, I'm checking in another thread to see if it's compatible. I know I need a bigger TB, and as soon as cash allows, I'll get one.

 

tmoss

Gettin Wired

Founding Member

Jun 28, 2001

7,153

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128

Saint Louis, MO

Jun 8, 2004

#7

• Jun 8, 2004

• #7

P head flow peaks out at .400" lift and doesn't gain but a couple of cfm if any at .500" lift. Your lifting to about .530" and I don't see that your benefiting. I just pulled SAE 257RWHP and 309RWTQ from a stock cam with 1.6 lifters without any tuning to the new combo running lean on the A/F wideband. Check out the sig.

 

astronut1885

Founding Member

Jan 31, 2002

1,899

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Assonet, MA

Jun 8, 2004

#8

• Jun 8, 2004

• #8

I put the Pro M back on, and went for a ride. Car definitely picked up a bit, pulled me harder. Tom- I don't get what you're telling me. Are you saying that I'm right on where I should be with my numbers, or that something's wrong?

 

tmoss

Gettin Wired

Founding Member

Jun 28, 2001

7,153

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128

Saint Louis, MO

Jun 8, 2004

#9

• Jun 8, 2004

• #9

I'm not saying anything is wrong, but I don't know why your lifting the valve so high if it is not benefitting you much in additional air flow into the cylinder. Save the wear and tear on the springs and go back to 1.6 rockers - if you have them.

 

astronut1885

Founding Member

Jan 31, 2002

1,899

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Assonet, MA

Jun 8, 2004

#10

• Jun 8, 2004

• #10

I don't. My mechanic had a friend with these rockers from a car he was parting out, and it was either these or stock stamped rockers. I got 'em for 100.00 in great shape, so I figured why not. I thought the GT40Ps were a good flowing head. everything I've read about them says they kick the snot out of stock heads. I wish I had porting work done before they went on, but money didn't allow it. I barely had enough to finish the motor. Anyway, what could be causing such a torque loss? I can't believe a small MAF and TB could really kill that much...

 

tmoss

Gettin Wired

Founding Member

Jun 28, 2001

7,153

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128

Saint Louis, MO

Jun 8, 2004

#11

• Jun 8, 2004

• #11

The P heads are great budget heads, but they don't flow any higher after .400" lift, so no real need to lift them that far. Since you don't have 1.6s, leave em in there. I don't think the TB and MAF are huge contributors but they may be costing something. If cam timing is not an issue, then it may be spark and/or fuel.

 

Mike86Stang

Advanced Member

Apr 11, 2000

10,296

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77

Red Lion, PA

Jun 8, 2004

#12

• Jun 8, 2004

• #12

I say get that a edel performer intake & feel the power... from what I've read the explorer intake isn't that hot but I don't know I've never seen or used one. So take that with a grain of salt... check out this link...http://www.corral.net/forums/showthread.php?s=&threadid=159577&highlight=GT40P+heads

I'd say get a 65mm TB on there as well. Gt-40P's have an very efficent chamber so they can take a decent amount of timing... I'd bump it to 16-18* personally.

 

tmoss

Gettin Wired

Founding Member

Jun 28, 2001

7,153

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128

Saint Louis, MO

Jun 8, 2004

#13

• Jun 8, 2004

• #13

MSTANG said:

... from what I've read the explorer intake isn't that hot but I don't know I've never seen or used one. So take that with a grain of salt...

Click to expand...

Yes, a BIG grain. No offense man, but you've been away or somethin. The Explorer is every bit as good as the Cobra OR GT40. I've got dynos AFM did of all 3 intakes on the same mule and they all made within 2-3 HP of each other at all rpm points. I also have an independent flow bench test (Victory
Engines) of a GT40 and Explorer and the Explorer flowed about 3cfm more!

 

astronut1885

Founding Member

Jan 31, 2002

1,899

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Assonet, MA

Jun 8, 2004

#14

• Jun 8, 2004

• #14

Yeah, my intake isn't the problem. My fuel system is stock, save for a 255 lph Walbro pump and a crane AFPR set at 41 psi. I bumped the timing up to 15-16*, and that helped a bit too, definitely more pull above 3k.

 

astronut1885

Founding Member

Jan 31, 2002

1,899

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Assonet, MA

Jun 15, 2004

#15

• Jun 15, 2004

• #15

Well, I installed my MSD 6al, and that didn't help. Now I know spark is more than covered, as everything is new. The Pro-M wasn't compatible, so I sold it. I want to get a 70mm TB and a 75mm PRO-M with some 24# injectors soon, but I still don't think that's the problem. My friend said that running 93 octane may have something to do with it. Timing is now set to 15-16*, no pinging on the 93 octane. I just can't figure out why the car is so sluggish. When I'm in third gear, for example, at like 1500, and I go WOT, the car chugs until about 3500 RPM. No torque, no pull. I just don't understand why she won't move. I even have trouble lighting up the tires from a roll in 1st gear at like 3k rpm. Once I get into the higher RPM, though, she moves really good, but that's where HP takes over and torque craps out anyway. I'm going to post my dyno sheets, maybe that can tell you something.

 

astronut1885

Founding Member

Jan 31, 2002

1,899

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Assonet, MA

Jun 15, 2004

#16

• Jun 15, 2004

• #16

Here's the dyno sheets from May 1st. The car was running with 22* timing, very rich, and untuned. I've since straightend out the tune ( I think), and added the MSD as far as performance stuff goes. Tell me if anything strikes you as odd with these spreads.

 

astronut1885

Founding Member

Jan 31, 2002

1,899

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Assonet, MA

Jun 15, 2004

#17

• Jun 15, 2004

• #17

The second sheet is two runs I made after about an hour of cool down. We dialed the timing back because we bumped it too high on the 4th run and it pinged. run 5 pinged too. Run 7 pinged on the second sheet, but by 8 we got a full run in. But even then, timing was still at like 20*. It ran rich, so we dialed the fuel pressure back a little too, and it got into a good ratio. I just can't figure this out.

 

cevtv

Founding Member

Sep 15, 2002

1,113

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37

Massachusetts

Jun 16, 2004

#18

• Jun 16, 2004

• #18

Have you changed the fuel filter? Just an idea...........

 

88stangmangt

Active Member

Nov 25, 2003

2,332

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48

Stafford,VA

Jun 16, 2004

#19

• Jun 16, 2004

• #19

sounds like a fuel issue run it on a good dyno with a wide band.

 

astronut1885

Founding Member

Jan 31, 2002

1,899

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39

Assonet, MA

Jun 16, 2004

#20

• Jun 16, 2004

• #20

Yep, new filter when the pump went in maybe 4 months ago. The dyno shop was a highly respected shop, with top notch equipment. I did run wideband, it's on the first sheet. I ran very rich at first, but we dialed it back a little bit. It leans out at the top end, probably because the 19s can't handle it.