Slower 1/4 time with more mods

[3vEvan]

Hi I'm new to this forum. I got this car a little over a year ago it's a 2006 mustang GT 4.6 3v with the auto trans. It was bone stock when I got it and I put a cold air intake and throttle body, offroad h-pipe and Slp loudmouth axle back and I was tuned by VMP and I ran a 13.5 at 102mph and then over last winter I did Ford racing hot rod cams, 4.10 gears and a one piece aluminum driveshaft and some Mickey Thompson S/S also tuned by VMP and the fastest pass I got was a 13.6 @ 106 mph with a better reaction time and since then I got a new tune from a local Dyno and picked up 30hp and 4tq and changed my spark plugs and switched to msd blaster coil packs and I just went back today and got my reaction time down yet again and I ran a 13.7 at 101mph and I don't understand it seems like the loss is in the 1st 60ft but I wanted to see if I could get any input. Thank you!

 

[stkjock]

Did you compare the DA from the different days?

also r u leaving exactly the same way?

hiw tall r the DRs?

 

[TheDarkPath]

Reaction time doesn't figure into ET. Can you post your slips from each track visit?

60' times mean a ton and if you 60' times are getting worse, that is what needs focus.

1. Are you doing a burnout to clean off and heat up the tires? If those are the Mickey Thompson ET Street Radials, they should get you out of the hole pretty quick. Drive around the water box, not through it and then back in to get the tires wet. From there, 2nd gear burnout until you see smoke.

2. What do you have the rear tire air pressure at? If ET Street Radials, should be around 18-20psi.

3. What is your launch RPM? Before the high stall TC on my 06 GT, I found launching at 1500 rpm was about my limit before it would push me through the beams but that netted me the best results. 60' times in the 1.7s with 4.10s and MT ET Streets.

4. Do you feel/hear tire spin on launch? 60' times will help tell this story.

5. Do you have traction control turned off? You don't want this on. Same with O/D, turn it off.

 

[3vEvan]

I have the slips not one ATM but I'm leaving at 1,500 rpms I have 295/55r15s but im thinking it's my cams every time my 60ft was around 2.03-2.15. and my tires don't spin it just hooks and goes but it's slow off the line it doesn't start pulling hard till after the 60ft probably after 1st gear. Thank you

 

[RED09GT]

With those cams and a 28" tire, you'll likely need looser torque converter to get out of the hole.
In the meantime, keep adding tire pressure and see if you can make it spin just a bit off the line.

 

[01yellerCobra]

I'd be curious to see if you gain anything back by switching back to the stock coil packs.

 

[Dino Dino Bambino]

With those cams and a 28" tire, you'll likely need looser torque converter to get out of the hole.

Exactly what I was thinking. With the HR cams, the torque curve drops off pretty steeply below 3500rpm so I'd recommend a torque converter which stalls at that rpm.

 

[Juice]

Trap speed is a general indicator of HP. Whatever happened between the 106 mph pass and the last pass of 101 mph I suspect you LOST power with the last changes.
60' times play huge into ET, but not as much to trap speed.

I'd be curious to see if you gain anything back by switching back to the stock coil packs.

Put the old coil packs back in and the previous tune and see what happens.

 

[07 Boss]

How many miles on the car? Could just be getting slower with age. That happens you know. Always build from the ground up for a successful race build. Wheels and tires, suspension and drive train, them add power. Can't just throw parts at it and expect results. A comprehensive build list and plan is essential.

 

[808muscle]

Hi I'm new to this forum. I got this car a little over a year ago it's a 2006 mustang GT 4.6 3v with the auto trans. It was bone stock when I got it and I put a cold air intake and throttle body, offroad h-pipe and Slp loudmouth axle back and I was tuned by VMP and I ran a 13.5 at 102mph and then over last winter I did Ford racing hot rod cams, 4.10 gears and a one piece aluminum driveshaft and some Mickey Thompson S/S also tuned by VMP and the fastest pass I got was a 13.6 @ 106 mph with a better reaction time and since then I got a new tune from a local Dyno and picked up 30hp and 4tq and changed my spark plugs and switched to msd blaster coil packs and I just went back today and got my reaction time down yet again and I ran a 13.7 at 101mph and I don't understand it seems like the loss is in the 1st 60ft but I wanted to see if I could get any input. Thank you!

Your baseline runs are spot on to what my car ran.....with the same mods back in the day. Go back to the VMP tune. You were making more power with it, 106 mph vs 102 mph. You gained power with the cams just not ET. When I added cams to my setup I had similar results... more mph but not much ET. DA with effect your ET a LOT. You have to compare apples to apples as the air changes constantly. I run the same tires 295/55/15 MT SS and run 14 psi.

Dump the dyno tune and run the VMP tune.

 

[stv_huff]

Torque converter. You gave up a lot of bottom end with all those peak hp mods. Need to launch a lot higher rpm. That’s my guess.

 

[3vEvan]

Thanks for all the responses and when I took the car to the Dyno the vmp tune had all kinds of blips in it and was running super rich. The first runs were good with vmp but after the cams and gears it ran so inconsistantly like that 106mph pass was the only one I had all the other traps that day were 99 or 100mph. The car also only has 47k miles on it and it seemed to react good when I changed my spark plugs and coil packs. I definitely think that I just lost too much low end with the cams kinda wish I just would have thrown a supercharger on and been done with it

 

[stkjock]

you did get the VMP tune adjusted for the cams and then got a local dyno tune?

 

[Dino Dino Bambino]

FPP HOT-ROD 4.6L-3V RECOMMENDED WOT CAM TIMING

RPM STOCK (deg retard) FPP (deg retard)
500 0 7
750 0 7
1000 0 7
1500 0 7
2250 0 7
3000 0 7
3750 0 12
4500 2.5 15
5000 3.5 20
5750 9 20
6500 9 20

https://performanceparts.ford.com/download/instructionsheets/FordInstShtM-6550-3V.pdf

 

[fdjizm]

Definitely lost some torque going to hot rod cams, I know I had to launch higher with them.
But the tune has to be spot on, you should gain about 30hp with the hot rods cams if they use the ford specs in the tune that dino posted above.

You can verify this in a log with the ACT CAM ANGLE pid which average both cams or see each individual with CAM ANGLE[0] and CAM ANGLE[1]

Should look something like this (the numbers never match perfectly)

I've gotten a tune from a reputable place and they left the stock cam timing with the hot rod cams and it made shit for power, till I finally logged and saw what was going on.
The car ran "fine" otherwise.

 

[RED09GT]

I didn't realize that you tried running the hot rods without being tuned for them. The main tuning issue with the hot rods is if the injector timing is not changed, you are spraying fuel at an open intake valve and it is getting sucked right of the open exhaust valve. The car will smell like raw fuel and the power and fuel economy will suck.

 

[SpecOps13]

You're getting a lot of good advice here... I currently have an 05 and SVT Cobra, stick cars so I can't relate directly. I can somewhat because I had an 89 Fox Body LX Coupe that had a built Automatic and a High Stall Converter W/Built Engine. Effective gear ratio of 3.88. From a Dig or a full throttle shift it would almost pull the seats out of the floor. You have to hit the right balance with your build and you will " Be There ".

Don Garlits taught me that with my first build in the 60's. My Dad was a Top Tuner back in the 60's but he refused to help me.. My Dad took my 283 Nova (Yes Don Reluctantly worked on a Chevy) to work one day, pulled up next to a Big Block Chevelle. All he said is that my Nova was Insanely Fast... Balance is Everything. Sorry for the run on story... I am an all Mustang Guy Now...

 

[jam07GT]

I run my MT drs (275s) at 22 psi. The most tire pressure you can run while maintaining traction is what you want.

You can see my mods below, and I only managed a 1.92 for 60 ft, but also that's at like 5,000+ DA which makes a difference. And 3K converter. Need converter with an NA car.

 

[01yellerCobra]

Don Garlits taught me that with my first build in the 60's. My Dad was a Top Tuner back in the 60's but he refused to help me.. My Dad took my 283 Nova (Yes Don Reluctantly worked on a Chevy) to work one day, pulled up next to a Big Block Chevelle. All he said is that my Nova was Insanely Fast... Balance is Everything. Sorry for the run on story... I am an all Mustang Guy Now...

You know Don Garlits? I imagine you have a good story or two.

 

[BottleRocket]

Hi. I'm new here but not to rodding. It looks to me like you're making too many changes at once. I believe I would back off some of your changes and add them back one-at-a-time. This should give you a better indication of what's going on inside the motor. I know it's fun making a lot of changes but you sometimes wind up with the problem you're having. One of my heroes, Bill Jenkins (yes, I know. He was a Chevy guy) always advised the A-B-A sequence. Add an item, test, remove item, test again. That's not practical with things like rear gears but coil packs would lend themselves to this testing sequence. Good luck.