GT Performance Mods 2005+ Mustang GT Performance and Technical Information

1/4 Mile Issues...please help

Old Aug 14, 2008 | 10:43 AM
  #1  
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1/4 Mile Issues...please help

OK, so since I've had my 07 I have only been to the track twice. The only difference between the first and second times I went was that the second time I had installed my MGW short throw shifter. I have the shifter set to the shortest throw and thought that would help my 1/4 mile time.

Here is what I am running

07 Mustang GT

5spd
3.55's
stock 18" polished bullits w/ stock BF's
Eibach pro kit
CDC shaker / performance air filter
Pypes O/R H-pipe
Borla Stingers
MGW Short throw

I am launching at 2,500 RPM, with traction control off. I avoid the water and do a small burn out before I stage.

Trip 1:

R/T .210
60' 2.252
330 6.601
1/8 10.084
MPH 70.30
1000 12.954
1/4 15.417
MPH 92.74

Trip 2 w/ MGW:

R/T .027
60' 2.452
330 6.824
1/8 10.238
MPH 75.90
1000 13.114
1/4 15.525
MPH 94.05

Now, in trip 2 I went faster in speed but slower in 1/4 mile

Now I know that a tune and intake is a step in the right direction, but im broke But I see stockers running faster.

Just looking for some advice and help before I go back tomorrow night. Any and all comments would be much appreciated!

Thanks!
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Old Aug 14, 2008 | 11:07 AM
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The numbers that caught my attention was the 60' times. Your 1st run was 2 tenths faster than the first. Your 60' times need some work. Launching does take some practice. Are reving to 2400-2500 RPMs than dumping the clutch? If so, try reving to 2000-2500 and feathering or letting the clutch out slowly while stepping on the gas. Another thing is drop your tire pressure to 20-25 PSI.
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Old Aug 14, 2008 | 11:35 AM
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LEO_06GT's Avatar
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Originally Posted by gmantheman
The numbers that caught my attention was the 60' times. Your 1st run was 2 tenths faster than the first. Your 60' times need some work. Launching does take some practice. Are reving to 2400-2500 RPMs than dumping the clutch? If so, try reving to 2000-2500 and feathering or letting the clutch out slowly while stepping on the gas. Another thing is drop your tire pressure to 20-25 PSI.
+1 your 60ft times are really bad even for stock tires.

BTW-Where are you located?
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Old Aug 14, 2008 | 11:56 AM
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60' is what killed you. You were able to shift quicker, which is why your trap speed was higher, but your launch was worse. 2 tenths of 60' is 3-4 tenths at the top end. Probably would've been a 15.1. But those are some extremely high times. I thought you were a v6 at first. Definitely time for a good tune, and a lot more practice getting out of the hole.

Are you spinning or hopping? Are you feathering the clutch or dumping it?
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Old Aug 14, 2008 | 01:11 PM
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what was the weather/track temp on the two different days?
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Old Aug 14, 2008 | 01:59 PM
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From: That town you drive through to get to Myrtle Beach
60' stands out the most, but I wouldnt worry unless its a consistently slower time;
I presume you're getting into the drag racing thing, and it's not unusual to run different times with a stock road going car. Just work on the launches, and you'll run better.
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Old Aug 14, 2008 | 02:17 PM
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Your 60' times is where you need to work on for sure. I don't think its your driving, you need to get better traction.....im sure your getting a lot of tire spin.
What gear are you in and what are your rpm's when you go through the traps????
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Old Aug 14, 2008 | 02:49 PM
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Originally Posted by LEO_06GT
+1 your 60ft times are really bad even for stock tires.

BTW-Where are you located?
Rhode Island
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Old Aug 14, 2008 | 02:50 PM
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Originally Posted by DarkFireGT
Are you spinning or hopping? Are you feathering the clutch or dumping it?
I can hold it steady at 2500 then I guess I "dump it". I basically take my foot right off the clutch

Please explain how to feather
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Old Aug 14, 2008 | 02:51 PM
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Originally Posted by Glenn
what was the weather/track temp on the two different days?
Both times the track was treated that day. Excellent weather, cool, no humidity. The big dogs were talking about how good the track was.
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Old Aug 14, 2008 | 02:53 PM
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Originally Posted by CooBra07
What gear are you in and what are your rpm's when you go through the traps????
I shift right into 4th right before the trap.

Someone told me last time at the track to shift sooner and finish out in 4th.

I basically bring it to just before redline then shift.
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Old Aug 14, 2008 | 03:18 PM
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You shouldn't need to shift to 4th. Those times are slow but its not all in the 60ft, you should easily be able to run a low 14 with a 2.2 60ft, to me it seems like you are shifting too slow or too early with your trap speed so low.
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Old Aug 14, 2008 | 03:32 PM
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steve-o, your 94 mph trap speed is way off and shows you car is only getting about 205-210 hp to the ground, which is maybe 240-250 hp at the engine - a far cry from the 300 hp that a stock GT makes.

One of two things will cause such a sharp power drop...

1. Did you have your car's computer tuned (either a handheld tuner or professional dyno tune) after installing the Shaker hood and exhaust mods? If not, you're likely running really lean, so you're car is likely pinging and the computer is pulling out a bunch of timing, which kills power, or...

2. What's the altitude of the track your at? Cars make much less horspower as the altitude goes up. You lose approximately 1% power for every 1,000 of altitude. And weather can make the car run worse. Cold, dense air makes the most horsepower, so if it is hot, humid, or a falling barometer, you'll run slower.
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Old Aug 14, 2008 | 03:48 PM
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Are you speed shifting? How fast you going at redline in 3rd? I have a 3.73 in my V6 and I think the tranny gearing is very close if not identical. I redline at 85 in 3rd so I would need to shift into 4th also. Shift 500 RPM or so below redline and give that a try.
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Old Aug 14, 2008 | 04:11 PM
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Originally Posted by Five Oh Brian
steve-o, your 94 mph trap speed is way off and shows you car is only getting about 205-210 hp to the ground, which is maybe 240-250 hp at the engine - a far cry from the 300 hp that a stock GT makes.

One of two things will cause such a sharp power drop...

1. Did you have your car's computer tuned (either a handheld tuner or professional dyno tune) after installing the Shaker hood and exhaust mods? If not, you're likely running really lean, so you're car is likely pinging and the computer is pulling out a bunch of timing, which kills power, or...

2. What's the altitude of the track your at? Cars make much less horspower as the altitude goes up. You lose approximately 1% power for every 1,000 of altitude. And weather can make the car run worse. Cold, dense air makes the most horsepower, so if it is hot, humid, or a falling barometer, you'll run slower.
The car has factory PCM and tune. I DO have a CEL due to to O2 sensors from having not cats on the car. Would this be causing the car to run lean and cause such power loss? Every time I go in for service they pull the code and it's always from the 02 sensors
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Old Aug 14, 2008 | 06:42 PM
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Originally Posted by steve-o
The car has factory PCM and tune. I DO have a CEL due to to O2 sensors from having not cats on the car. Would this be causing the car to run lean and cause such power loss? Every time I go in for service they pull the code and it's always from the 02 sensors
Now we're getting somewhere, steve-o. You have made some airflow changes to the engine, and your PCM is reacting to what it thinks are odd inputs and is safeguarding itself against problems. Hopefully, one of the computer experts will jump in and help me out here, but I think your car is responding by richening up too much by going into an open fuel loop. This will kill power just as much as running lean, but won't cause pinging like a lean condition, at least. You really need a tune to get your air-fuel ratio fixed, as well as timing and fuel tables optimized for your modifications. Your car should easily run 103-104 mph through the traps once you've done that, maybe even faster.
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Old Aug 15, 2008 | 07:42 PM
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Definitely stay in third with those 3:55's Try shifting right around 6200 rpms, any farther you'll hit the limiter and game over.
I cross the line in 3rd around 6300 rpms, and extra shift is only going to hurt times. I do run a smaller drag radial so it does give me a tad higher "gear"
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Old Aug 15, 2008 | 08:04 PM
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All I can say is my first time out to the track I was totally stock except for a CAI and tune. My best run I dumped the clutch at 2200, shifted at 6200 and crossed the line in 3rd gear right at redline. I ran a 13.68@103. I believe you have a computer issue. If you have the funds, get a CAI and tuner from one of the reputable companies on these forums. With the cats removed, it will be a huge difference.
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Old Aug 15, 2008 | 08:08 PM
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I was always under the impression a tune for cat delete was not needed. But what you get is a tune that just turns off the rear o2 sensors. But there could be something to that I guess, only know what Ive read around the boards.
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Old Aug 16, 2008 | 03:25 AM
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if you cant afford noth an intake and tune, call brenspeed and just get a tuner with a custom tune. you said you have a performance filter, doesnt flow as well as a full intake system but it could cause a problem, my dad put a K&N filter on his explorer (stock filter replacement) and cut a bigger opening and he got a CEL for flowing too much. each intake system is a little different to tune for, so it would be best to get a tune and intake at the same time.
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