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Discussion Starter #1
hello guys,

I am newbie here, so maybe Ill ask some dumb already 100x asked questions - but Iv checked the forums and cant find my answers...
Also please excuse my bad english.

Almost 3 years I am buliding my Mustang 2005, bellow please find very short list of main changes and modifications.
Now i am on 600hp and 810Tq and best 1/4time 11.9 - and I am stuck there...
I think I should have a beter time, but I am not sure.

My main actual question is about gear ratio, tire preasure, shift point and launch RPM.

(My final goal is 1/4 time 10.xx, but its a long way, I know.)
(I still think that I should get more HP from this engine, but I am stuck there aswell)

Ill be glad for any advices, thank you in advance!



**** E N G I N E ****

5.0L MODULAR STROKER SHORTBLOCK M-6009-A46X
1.9L TVS VMP Supercharger
66mm Supercharger Pulley
STOCK 3V HEADS (from 2005 4,6 V8 engine)
FORD RACING HOT ROD PERFORMANCE CAMSHAFTS
Manley 3V HP Valvev springs
FORD RACING 47 LB/HR FUEL INJECTOR SET
FORD RACING Throttle Body OEM 60mm GT500 2007-2014
FORD RACING HIGH PERFORMANCE DUAL FUEL PUMP KIT (05-09 GT)
AFCO PRO-SERIES HEAT EXCHANGER W/ FANS (07-12 GT500)
Kooks Headers Long Tube Headers + Kooks Headers X-Pipes (no cat)
Kenne Bell Boost-A-Pump
Kenne Bell Boost-A-Spark
MSD Launch Control

*** DRIVETRAIN ***

STEEDA TRI-AX SHORT SHIFTER - TR-3650 (05-10 GT)¨
McLeod RST Street Twin Clutch Kits 6912-03
McLeod Aluminum Flywheels 563408
FORD RACING 4.10 GEARS (05-09 GT)

*** SUSPENSION ***

BMR Control Arms, controls, relocation, sway bar, K-member
stock springs
Strange Externally Adjustable Mustang Shocks
Air Lift 1000 Load Assist Rear Spring Kits

*** WHEELS ***

15" Weld Racing Draglite Polished Wheels 90-510354
315/60-15 Mickey Thompson ET Street Radial Tires 3763R


Dyno tested 600 RWHP, 810 troque
Shift point 6000 RPM (limeter 7000 RPM)
Launch RPM 2800
Tire preasure 8 psi

If you check my time slips, yesterday Iv started on 12,4sec and ended on 11.915 sec (1.815 6oft)
(we changed only launch RPM and tire preasure during the day)
but my max speed is still almost exactly 195 km/h - and I dont know why.
I cant improve my 1/4mile time anymore.

I have few questions:

==1==
with 600hp and 810Tq, should I still go with 4.1 gear ratio?

==2==
I think that 2800 launch RPM is far too low - but with this tires tire preasure I cant go higher
any advice?

==3==
generally, I would like to ask you for any advices, how to improve my 1/4 time with this car configuration, or what changes are you recomending.

==4==
fi you check the dyna graph, what shift RPM can you recomend?

...and:
I am doing something wrong - or I simply cant go faster with 600hp?


Thank you very much for your help!

Tomas
 

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Looks like you make peak power around 6000 rpm what's your trap rpm? You want it close to your peak power
 

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Discussion Starter #3
Looks like you make peak power around 6000 rpm what's your trap rpm? You want it close to your peak power

I am not sure, If my answer is correct:
as you can see on the dyno chart, engine is tested up to 6500 RPM (limeter is set on 7000 RPM)
HP still going up, peak on 6500, torque peak is on 4500 RPM
my shift light is set on 6000 RPM
I dont have datalog so I can judge by Dyno test and time slip only
do I am shifting too late?

thank you VERY much for your reaction, I am grateful for any advices.
 

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I wonder on your shifting abilities. Are you capable of performing speed shifts or no? The reason I ask is because with my N/A 325 rwhp 08' Bullitt I have gone 12.78 @ 107+ mph. Also it looks to me like your rear tire pressure is way to low. Only 8 psi? really? Should be up over 12 psi in my estimation.
 

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Discussion Starter #5
I wonder on your shifting abilities. Are you capable of performing speed shifts or no? The reason I ask is because with my N/A 325 rwhp 08' Bullitt I have gone 12.78 @ 107+ mph. Also it looks to me like your rear tire pressure is way to low. Only 8 psi? really? Should be up over 12 psi in my estimation.
- I wonder on your shifting abilities. Are you capable of performing speed shifts or no? The reason I ask is because with my N/A 325 rwhp 08' Bullitt I have gone 12.78 @ 107+ mph.
if you mean with "speed shift" shifting without a clutch, you can be right, there is a reserve.
I am in "10 second club" on my Harley and I am shifting without clutch there.
But I still dont have balls for shifting without clutch in my ponny.

- Also it looks to me like your rear tire pressure is way to low. Only 8 psi? really? Should be up over 12 psi in my estimation.
yes, it should, but I am simply not able to launch with higher preasure.
Thats why I asked about the gears ratio.
I should be able to launch at 4000 rpm + with those tires.
Iv try on Saturday:
12psi / 2900 launch RPM : heavy spinning
10psi / 2900 launch RPM : heavy spinning
10psi / 2700 launch RPM : spinning
9psi / 2600 launch RPM : cant launch, too low RPM
8psi / 2800 launch RPM : "good" start
 

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Then you are going to need some sort of boost controller to limit boost on the launch and then ramp it in after the 60' or so. Running only 8 psi in the tires is like dragging two flat tires down the track, the amount of drag provided by those two tires at that pressure is pretty big. Lots of rolling resistance. It would work a lot better to launch at 6-7 psi and then ramp in the rest of the boost once the car takes a set and gets going. So either sort out a boost controller, or come up with a timing retard to kill the power on the hit and then ramp in the timing once the car gets going. Problem with retarding the timing, while killing a lot of power to get going, it is hard on pistons. What does the car weigh? What is the weight split front to rear? Are the rear shocks double adjustable? How about the front. What struts/springs on the front? Sway bar removed?
 

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Discussion Starter #7
Then you are going to need some sort of boost controller to limit boost on the launch and then ramp it in after the 60' or so. Running only 8 psi in the tires is like dragging two flat tires down the track, the amount of drag provided by those two tires at that pressure is pretty big. Lots of rolling resistance. It would work a lot better to launch at 6-7 psi and then ramp in the rest of the boost once the car takes a set and gets going. So either sort out a boost controller, or come up with a timing retard to kill the power on the hit and then ramp in the timing once the car gets going. Problem with retarding the timing, while killing a lot of power to get going, it is hard on pistons. What does the car weigh? What is the weight split front to rear? Are the rear shocks double adjustable? How about the front. What struts/springs on the front? Sway bar removed?
- Then you are going to need some sort of boost controller ..
thats interesting... is it a "common" solution? any recomedation?

- What does the car weigh?

1625 kg (3580lb)

- What is the weight split front to rear?

Front 55.60 %
Rear 44,40 %

- Are the rear shocks double adjustable? How about the front. What struts/springs on the front?

yes, both.
Strange Externally Adjustable Mustang Struts S6009LM
Strange Externally Adjustable Mustang Shocks S6008LM

I had them first time this Saturday.
They both have 10 performance-adjusting rebound settings - and I had both (front and rear) on 5
Iv changed the tire preasure and launch RPM to get a best result, not the shocks this time.
Do you have recomendation, how to set them?

ad springs:
stock
Iv checked the market and Iv not find any drag springs for 2005-2009. The Eibach ones (which included the air bag asweel) are out of stock everywhere, available for 79-04 only
Atleast Iv got the bags to the rear springs
Air Lift 1000 Load Assist Rear Spring Kits 60841
Iv used 15psi on the left one and 35psi on right


- Sway bar removed?

rear
2005 FORD MUSTANG BMR Sway Bars SB023R

front is still there
 

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