Drag Racing W/ Forced Induction

[FRS Justin]

Originally Posted by Dream20b

Okay, So I did some passes at the strip last Saturday and i'm hitting the rev limiter before attempting to shift into 5th.

Current:
Manual Transmission
Unknown Horsepower. estimating 260-270 RWHP
Bridgestone Turanza El400 Hockey Pucks.


Relevant info:

Factory suspension settings
2013 FRS
Sprintex 210 Supercharger
Tomei Equal Length Headers
E85
70mm Pulley (~11 PSI)
Stock Gearing
215/45/17 tires resulting in a 24.6" tire diameter
7450 RPM rev limit
topping out at 12.9 at 105-106 MPH in 4th gear riding out the top 50 feet or so on the limiter


Due to the limiter I have a choice of attempting to shift to 5th or riding the limiter. 5th gear is impossible to shift into within 50 feet at 105 mph.


The easiest change is to increase the rev limiter to 7800:


Proposed changes option 1:
7800 RPM rev limit
top speed in 4th around 114 or 115


Since my tires are nearing the end of their useful life, I may be interested in changing rear wheels to 17x7.5 and tires to stickier street tires sized at 245/45/17 tires resulting in the following:



Proposed changes option 2:
7800 RPM Rev limiter
245/45/17 tires for a 25.7" tire diameter
top speed in 4th around 119 or 120


The last option is 17x8 wheels and tires with stickier street tires sized at 265/45/17 tires resulting in the following:



Proposed changes option 3:
7800 RPM Rev limiter
265/45/16 tires for a 25.4" tire diameter
top speed in 4th around 118 or 119, still simple




I probably put way too much thought in for a tenth or two, but every tenth counts in drag racing.


Anyway, Which setup makes the most sense realistically, not necessarily monetarily?

Option 4: Weir performance gear change to 4.56 or buy mine lol

[#maverick#]

Originally Posted by Dream20b

Okay, So I did some passes at the strip last Saturday and i'm hitting the rev limiter before attempting to shift into 5th.

Current:
Manual Transmission
Unknown Horsepower. estimating 260-270 RWHP
Bridgestone Turanza El400 Hockey Pucks.


Relevant info:

Factory suspension settings
2013 FRS
Sprintex 210 Supercharger
Tomei Equal Length Headers
E85
70mm Pulley (~11 PSI)
Stock Gearing
215/45/17 tires resulting in a 24.6" tire diameter
7450 RPM rev limit
topping out at 12.9 at 105-106 MPH in 4th gear riding out the top 50 feet or so on the limiter



Due to the limiter I have a choice of attempting to shift to 5th or riding the limiter. 5th gear is impossible to shift into within 50 feet at 105 mph.


The easiest change is to increase the rev limiter to 7800:


Proposed changes option 1:
7800 RPM rev limit
top speed in 4th around 114 or 115


Since my tires are nearing the end of their useful life, I may be interested in changing rear wheels to 17x7.5 and tires to stickier street tires sized at 245/45/17 tires resulting in the following:



Proposed changes option 2:
7800 RPM Rev limiter
245/45/17 tires for a 25.7" tire diameter
top speed in 4th around 119 or 120


The last option is 17x8 wheels and tires with stickier street tires sized at 265/45/17 tires resulting in the following:



Proposed changes option 3:
7800 RPM Rev limiter
265/45/16 tires for a 25.4" tire diameter
top speed in 4th around 118 or 119, still simple




I probably put way too much thought in for a tenth or two, but every tenth counts in drag racing.


Anyway, Which setup makes the most sense realistically, not necessarily monetarily?

I have a 245/45/17 on my stock wheels i still have to shift into 5th. Im not too good with with gearing but i think throwing a 3.73 is300 diff might help.
i hate it when you run out of gear and hit the rev limiter it just falls flat on its face instead bouncing off the rev limiter

[Dream20b]

Originally Posted by #maverick#

I have a 245/45/17 on my stock wheels i still have to shift into 5th. Im not too good with with gearing but i think throwing a 3.73 is300 diff might help.
i hate it when you run out of gear and hit the rev limiter it just falls flat on its face instead bouncing off the rev limiter

What is your rev limiter set at?

[Kdej1]

Originally Posted by Dream20b

Okay, So I did some passes at the strip last Saturday and i'm hitting the rev limiter before attempting to shift into 5th.

Current:
Manual Transmission
Unknown Horsepower. estimating 260-270 RWHP
Bridgestone Turanza El400 Hockey Pucks.


Relevant info:

Factory suspension settings
2013 FRS
Sprintex 210 Supercharger
Tomei Equal Length Headers
E85
70mm Pulley (~11 PSI)
Stock Gearing
215/45/17 tires resulting in a 24.6" tire diameter
7450 RPM rev limit
topping out at 12.9 at 105-106 MPH in 4th gear riding out the top 50 feet or so on the limiter



Due to the limiter I have a choice of attempting to shift to 5th or riding the limiter. 5th gear is impossible to shift into within 50 feet at 105 mph.


The easiest change is to increase the rev limiter to 7800:


Proposed changes option 1:
7800 RPM rev limit
top speed in 4th around 114 or 115


Since my tires are nearing the end of their useful life, I may be interested in changing rear wheels to 17x7.5 and tires to stickier street tires sized at 245/45/17 tires resulting in the following:



Proposed changes option 2:
7800 RPM Rev limiter
245/45/17 tires for a 25.7" tire diameter
top speed in 4th around 119 or 120


The last option is 17x8 wheels and tires with stickier street tires sized at 265/45/17 tires resulting in the following:



Proposed changes option 3:
7800 RPM Rev limiter
265/45/16 tires for a 25.4" tire diameter
top speed in 4th around 118 or 119, still simple




I probably put way too much thought in for a tenth or two, but every tenth counts in drag racing.


Anyway, Which setup makes the most sense realistically, not necessarily monetarily?

What was the 60ft on this run? And how was the traction through 1st?

[Dream20b]

Originally Posted by Kdej1

What was the 60ft on this run? And how was the traction through 1st?

This particular 60 ft was 2.003 and the traction in first was nothing to write home about. The lowest I've gotten was a 1.9 60' on these tires.

[#maverick#]

Originally Posted by Dream20b

What is your rev limiter set at?

8000

[Kdej1]

Originally Posted by Dream20b

This particular 60 ft was 2.003 and the traction in first was nothing to write home about. The lowest I've gotten was a 1.9 60' on these tires.

If you end up getting larger tires, it could help your 60ft alot.. The lower your 60 get the lower your trap speed gets. The lower the trap, maybe it'll help with not touching the limiter..

[Dream20b]

received my re-tune from @moto-mike today, Will be going to the track again soon, and posting some new numbers, hopefully.

[STV3]

Originally Posted by #maverick#

We need a drag racing thread.

What setup are you guys running. Clutch, SC or TC, Tires, Suspension, misc?

I have p&l's kit and I launch at 4000 on 245/45/17 nitto nt555rs, @ 25 psi it wheel hops nasty, at 18 - 20 psi it wheel hops but not as bad.

What are you guys running, curious to hear other people's setups

Ditch the drag radials and get a set of drag slicks. When you launch, the sidewall wrinkles and that takes a lot of strain off the drivetrain and will help with that wheel hop.

[Xero-Limit]

Originally Posted by Dream20b

received my re-tune from @moto-mike today, Will be going to the track again soon, and posting some new numbers, hopefully.

Didn't realize that was you...NICE TIME!!! Making the most out of that blower for sure.

[johan]

Originally Posted by STV3

Ditch the drag radials and get a set of drag slicks. When you launch, the sidewall wrinkles and that takes a lot of strain off the drivetrain and will help with that wheel hop.

This!

Launching with boost on street tires (and drag radials are even worse) is a one way trip to something in the drivetrain breaking.

Get slicks, make sure the wheels are hub centric (or have hub centric rings), run them at 10-11psi hot. Smoke them in the water box, launch at 6500rpm. Profit.

If you're serious about getting the best time out of your setup, slicks are the only way to go. Anything else is just a waste of tire/clutch/drivetrain. I would bet money that slicks will completely eliminate your wheel hop unless you start making more than 400whp. Messing with bushings is just going to make your car more harsh and won't make you go any faster.

Background: I have over 250 passes at the track. In cars ranging from 150whp to 650whp.

[FRS Justin]

I have launched at 7600 rpm and ran a 1.88 on drag radials. 86's are light hook up well with the right suspension mods and adjustments. I would not run less than 15psi in the rear any lower and you are just adding rolling resistance...

[sosick]

Originally Posted by #maverick#

I did a few more test hits.... on a road in mexico...

I set my air pressure in back to 16 psi. Raised the 2 step to 6000 rpms to build about 4-5 lbs of boost to do a burnout. Lit them up for 6 seconds or so.

Lowered my 2 step to 5250 - 5300, preloaded the drivetrain with the hand brake, and slipped it out aggressively. I spun for about 20 feet and then it hooked and booked. No more wheel hop

Road totally differnt from track tho shouldve tried this on the track

[Kdej1]

I have personally always used the ebrake to help preload.. I'd say it's definitely good practice