600+hp gear ratio and RPM help

[TomasV]

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

[squirrel]

what is the engine RPM at the end of the run? going through the finish line

and what gear is the transmission in? is it in a 1:1 ratio gear? (4th gear?)

I have a couple old Chevys I have run with a supercharger with similar power, I have run several different rear gears. As long as I have good traction, I run quickest with a gear that puts the engine RPM at the finish line somewhere between shift point and redline. about 6500 would be good. The tires you have are about 28 inches tall?

[Hemi Joel]

It should go 10.68 @ 128 mph, assuming a 3700 lb. race weight. Something major is wrong. Start with the basics. Verify that it is not starving for fuel and leaning out with a fuel air ratio meter. Check timing, and valve lift to make sure nothing has changed since the dyno tune. Weigh it. Check the air intake for obstructions. Make sure the blower belt isn't slipping.
Good luck, keep us posted.

[Hemi Joel]

Get one of these: http://www.summitracing.com/parts/MOR-89650/ THis will help you more than anything. It also calculates all of your gear ratio stuff.

When you weigh the car, this tool will combine your power and weight to tell you your theoretical ideal ET and MPH in the 1/4 mile. Start on getting the mph where is should be. If the car is not running the proper MPH, you can't optimize the ET. If it is not running the MPH, it is not making the power it did on the dyno, (or the dyno was "happy") THat is why you need to go over the basic tuning stuff, to find out where your power went.

Once you have it running the MPH, then work on hook. You should be able to launch at 4000 rpm + with those tires. Diving technique, tire pressure, weight transfer and suspension/shock tuning will get you there.

[TomasV]

what is the engine RPM at the end of the run? going through the finish line

and what gear is the transmission in? is it in a 1:1 ratio gear? (4th gear?)

I have a couple old Chevys I have run with a supercharger with similar power, I have run several different rear gears. As long as I have good traction, I run quickest with a gear that puts the engine RPM at the finish line somewhere between shift point and redline. about 6500 would be good. The tires you have are about 28 inches tall?

- what is the engine RPM at the end of the run? going through the finish line

only 4500-5000 RPM, 4th gear
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 se on 6000 RPM
do I am shifting too late?


- and what gear is the transmission in? is it in a 1:1 ratio gear? (4th gear?)

yes, 4th gear

- I have a couple old Chevys I have run with a supercharger with similar power, I have run several different rear gears. As long as I have good traction,

I run quickest with a gear that puts the engine RPM at the finish line somewhere between shift point and redline. about 6500 would be good. The tires you have are about 28 inches tall?

my problem probably is, that I dont have good traction, since I am not able to made proper start above 2800 launch RPM.
Yes, you are right, I should finish at 6500 RPM - do you thing that change the gear from 4.1 to let say 3.55 is the right way?
tires:

http://www.summitracing.com/int/parts/mtt-3763r

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

[squirrel]

No, if you go to 3.55 then you will have even less rpm at the finish line. but it looks like you are going about 120 mph (194 kph) at the finish line? if I am reading the time slip properly. with a 29 inch tall tire, that should be about 5500 RPM in that gear?

I don't have much experience with launching cars drag cars with a clutch, so I can't really help you fix that problem.

[DanStokes]

Tomas - WELCOME to BangShift! I think your English is amazing and so much better than my Czech! It's fun for us to have folks from other countries (we even allow Canadians!) and to see what they are doing.

I'm not a drag racer (I do Land Speed Racing (LSR)) so I'll leave the advice to the guys who do that.

Best of luck!

Dan

[TheSilverBuick]

Yeah, I'd get a rpm and speed calculator that uses rear gear, transmission and tire height ratios and play with the numbers based on your tire height and 1:1 transmission gear, and expected MPH to decide what rear gear to run.

My Buick's case, in a very optimistic world (no dyno information), I figured there is no way I'd run over 118mph. So with that in mind I back calculated that trap speed in the 1/4, which with my 26.5" tall tire, 5,800rpm shift point, and 1:1 gear it would use 3.89 gears, so that is what I ordered and installed. At the end of the day I was running 112-113mph and crossing the line at 5600rpm, which is close enough for me to say I don't need to change the gearing, particularly if I find a few more spare horsepowers around. My manual transmission 60ft's blow at 1.85, as well as a dozen other factors(including operator!) keep me snugly in the mid-12's.

[TheSilverBuick]

Re-reading what you have, IMO 47lb/hr injectors must just barely support the HP you are making. I would think you'd need a minimum of 55lb/hr injectors (~60lb/hr - 80lb/hr) to make 600HP at a safe 85% duty cycle. From pure internet injector math, the injectors should be maxing out around 525-530 horsepower.

I would look at any datalogs you have on injector duty cycle, and if they are up over 85%, start looking at fuel injectors. Conversely, it should be running lean as well.

[TomasV]

It should go 10.68 @ 128 mph, assuming a 3700 lb. race weight. Something major is wrong. Start with the basics. Verify that it is not starving for fuel and leaning out with a fuel air ratio meter. Check timing, and valve lift to make sure nothing has changed since the dyno tune. Weigh it. Check the air intake for obstructions. Make sure the blower belt isn't slipping.
Good luck, keep us posted.

- It should go 10.68 @ 128 mph, assuming a 3700 lb. race weight. Something major is wrong.

well, that would be nice :-)

- Start with the basics. Verify that it is not starving for fuel and leaning out with a fuel air ratio meter.
- Check timing, and valve lift to make sure nothing has changed since the dyno tune.
- Weigh it. Check the air intake for obstructions.
- Make sure the blower belt isn't slipping.

thank you very much - will do.
I dont have datalog so I nan judge by Dyno test only.
We solved the fuel problem durin the winter, I have new MMR fuel rails, Ford Racing dual fuel pump and Kenne Bell Boost-a-pump - and everythong seems ok on dyno
New valves etc.
I will weight it for the caltulations.
and yes - I have to check the blower belt

Thank you very much !

[TomasV]

Get one of these: http://www.summitracing.com/parts/MOR-89650/ THis will help you more than anything. It also calculates all of your gear ratio stuff.

When you weigh the car, this tool will combine your power and weight to tell you your theoretical ideal ET and MPH in the 1/4 mile. Start on getting the mph where is should be. If the car is not running the proper MPH, you can't optimize the ET. If it is not running the MPH, it is not making the power it did on the dyno, (or the dyno was "happy") THat is why you need to go over the basic tuning stuff, to find out where your power went.

Once you have it running the MPH, then work on hook. You should be able to launch at 4000 rpm + with those tires. Diving technique, tire pressure, weight transfer and suspension/shock tuning will get you there.

- Get one of these: http://www.summitracing.com/parts/MOR-89650/ THis will help you more than anything. It also calculates all of your gear ratio stuff.
thanks! I will

- When you weigh the car, this tool will combine your power and weight to tell you your theoretical ideal ET and MPH in the 1/4 mile. Start on getting the mph where is should be.
If the car is not running the proper MPH, you can't optimize the ET. If it is not running the MPH, it is not making the power it did on the dyno, (or the dyno was "happy")
THat is why you need to go over the basic tuning stuff, to find out where your power went.
- ok, got it

- Once you have it running the MPH, then work on hook.
- You should be able to launch at 4000 rpm + with those tires.

exactly!! and I am not able to!

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

- Diving technique, tire pressure, weight transfer and suspension/shock tuning will get you there.

suspension/shock

http://www.summitracing.com/int/parts/mtt-3763r

http://www.summitracing.com/int/parts/bmr-utca019r/overview/make/ford

http://www.summitracing.com/parts/bmr-tca021r/overview/make/ford

http://www.summitracing.com/int/parts/bmr-cab005r/media/images/year/2005/make/ford/model/mustang

http://www.summitracing.com/parts/bmr-ucm001r/overview/year/2005/make/ford/model/mustang

http://www.summitracing.com/parts/bmr-sb023r/overview/year/2005/make/ford/model/mustang

http://www.americanmuscle.com/sr-swaybar-relocation-bracket-0514.html

http://www.summitracing.com/int/parts/str-s6008lm/overview/

http://www.summitracing.com/int/parts/str-s6009lm/overview/

http://www.summitracing.com/int/parts/air-60841/overview/

stock springs with air bags

running the bags left with 5psi, right 35psi

ad above mentioned adjustable shocks:
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?

[TomasV]

No, if you go to 3.55 then you will have even less rpm at the finish line. but it looks like you are going about 120 mph (194 kph) at the finish line? if I am reading the time slip properly. with a 29 inch tall tire, that should be about 5500 RPM in that gear?

I don't have much experience with launching cars drag cars with a clutch, so I can't really help you fix that problem.

"..No, if you go to 3.55 then you will have even less rpm at the finish line.."
ok, got it.

yes, you are right, its 193-5 kph (120mph) and around 5000 RPM (far before my shift point)

[TomasV]

Tomas - WELCOME to BangShift! I think your English is amazing and so much better than my Czech! It's fun for us to have folks from other countries (we even allow Canadians!) and to see what they are doing.

I'm not a drag racer (I do Land Speed Racing (LSR)) so I'll leave the advice to the guys who do that.

Best of luck!

Dan

thank you Dan VERY much, you are very kind!

[TomasV]

Yeah, I'd get a rpm and speed calculator that uses rear gear, transmission and tire height ratios and play with the numbers based on your tire height and 1:1 transmission gear, and expected MPH to decide what rear gear to run.

My Buick's case, in a very optimistic world (no dyno information), I figured there is no way I'd run over 118mph. So with that in mind I back calculated that trap speed in the 1/4, which with my 26.5" tall tire, 5,800rpm shift point, and 1:1 gear it would use 3.89 gears, so that is what I ordered and installed. At the end of the day I was running 112-113mph and crossing the line at 5600rpm, which is close enough for me to say I don't need to change the gearing, particularly if I find a few more spare horsepowers around. My manual transmission 60ft's blow at 1.85, as well as a dozen other factors(including operator!) keep me snugly in the mid-12's.

thank you! Iv just pleced the order for the calculator. I hope Ill be able to do it and get the right numbers, since I am now totaly lost and have no idea, what ears I should use

[TomasV]

Re-reading what you have, IMO 47lb/hr injectors must just barely support the HP you are making. I would think you'd need a minimum of 55lb/hr injectors (~60lb/hr - 80lb/hr) to make 600HP at a safe 85% duty cycle. From pure internet injector math, the injectors should be maxing out around 525-530 horsepower.

I would look at any datalogs you have on injector duty cycle, and if they are up over 85%, start looking at fuel injectors. Conversely, it should be running lean as well.

ok, thanks! I will check it.!
The car was tuned on brand new SuperFlow dyno (www.superflow.com) and their reputation is very decent, but will check it, certainly.
Will check the injectors aswell
Thank you!