Drag Suspension Setup Question

[DaveMan]

Hey guys, Just wondering about my suspension. I just bought the car a few months ago the way it is modded and only was to the track once. I ran a best 1/4 of 12.538 @ 113mph, best 60' 1.918. But I was having troubles shifting that time. I have the hard shifting issue fixed and am going back in a couple weeks. I didn't launch too hard that weekend either.


So I am running 26x10.50x16 ET Streets for now, I will upgrade to 11.50s once these are worn out, I had them from my previous car. It's a 2.93 upper only with a big air filter, lfp he, borla stinger catback, basanni catted x pipe. I have the Brooks Stage IV Extreme suspension system that came with the car. I don't know how well it's setup for the 1/4 though. It's more of a road track setup. Is this hurting my times? Here's what's in the kit:
-Bilstein struts
-Bilstein shocks
-Full length sub frames
-MM HD strut tower brace
-G-load brace
-MM 4 bolt caster camber plates
-Sport Springs (Don't know the brand but they are black)
-Endlink kit
-Sway bar bushings
-Aluminum steering rack bushings
-Rear steer kit
-Kenny Brown HD Forward torque brace with aluminum bushings
-Kenny Brown Rear shock tower brace
-Adjustable front sway bar
-Front spring isolators
-Rear spring seats
-Steering shaft assembly
-Front control arm bushings
-IRS polyurethane subframe bushings

If this is a pretty good setup how would you launch it? I have a Wotbox to put in so I'm going to be launching off it.

 

[rw95gt]

i have a 2 step and i generally spin at anything over 4000rpms on the box. without the box i launch at around 4500 rpms to 5000 rpms. i try to hold the gas steady about 500rpms less then what i want to leave at and put it to the floor as i let off the clutch. im running the 26/11.5/16 et streets at around 13 psi. i cut low 1.6 short times. my suspension consists of only cut springs and no front sway bar at the track. i don't think your suspension setup will hurt you. practice will help you the most. good luck!

 

[DaveMan]

i have a 2 step and i generally spin at anything over 4000rpms on the box. without the box i launch at around 4500 rpms to 5000 rpms. i try to hold the gas steady about 500rpms less then what i want to leave at and put it to the floor as i let off the clutch. im running the 26/11.5/16 et streets at around 13 psi. i cut low 1.6 short times. my suspension consists of only cut springs and no front sway bar at the track. i don't think your suspension setup will hurt you. practice will help you the most. good luck!

Do you generally get better times launching on the 2-step? Or no 2-step?

 

[carfax]

i honestly think if you stick with the irs for drag racing your still going to be fighting it for the whole time.

my first question is, what do you mainly do to your car? daily it? weekend play toy?

second, how far do you want to go with it?

its all about what you want to do with your car, but if you want suspension advice about drag racing i just need to know a few things.

 

[IronTerp]

i honestly think if you stick with the irs for drag racing your still going to be fighting it for the whole time.

my first question is, what do you mainly do to your car? daily it? weekend play toy?

second, how far do you want to go with it?

its all about what you want to do with your car, but if you want suspension advice about drag racing i just need to know a few things.

The IRS can actually be made to be quite efficient at the drag strip. Of course having an extra 120 lbs over the rear tires certainly doesn't hurt. Tons of folks have had great success running the IRS at the strip with Terminators and there's been several folks hit 1.4's in the 60', and plenty in the 1.5's. Antex and Hisssnsvt have hit 1.3's with the IRS.

And to the OP, you already have some pretty good tires, now you need to experiment with shock and strut settings, figure out the best RPM, rear tires pressure, and launch technique and then try and get some weight off the front of the car. Maybe consider removing the sway bar for the track, replacing your factory battery with a light weight version, and possibly running some front skinnies with bias ply tires.

 

[carfax]

The IRS can actually be made to be quite efficient at the drag strip. Of course having an extra 120 lbs over the rear tires certainly doesn't hurt. Tons of folks have had great success running the IRS at the strip with Terminators and there's been several folks hit 1.4's in the 60', and plenty in the 1.6's. Antex and Hisssnsvt have hit 1.3's with the IRS.
QUOTE]

yes i know all about how to make a irs work at a drag stip. i priced out irs parts and straight axle parts...irs just seemed ridiculous to keep when the irs will eventually break again. plus, when a mustang is basically a factory 4 link why keep a "bolt" in irs.

if his car is just a daily and just weekend cruiser then yes keep the irs and enjoy it. thats why i always ask them questions before i give my opinion.

 

[03slobra2]

Sounds a lot like a road race set up... you are going to be fighting that to get good weight transfer...

anthing can be done with proper driving and practice...GL OP

 

[DaveMan]

The car is a weekend driver and a daily driver on nice summer days. I want to keep the IRS. I do run the quarter a lot in the summer though. No road racing at all around here though.

So far I've gathered that I should unhook the front swaybar for the track, maybe get a light weight battery but I don't know how much difference it would make though. Or move it to the truck by I'd rather keep it up front to keep trunk space since we travel in the car in the summer as well.

My shocks/struts are not adjustable, at least I don't think they are. How can I tell? They are yellow so maybe they are stock? The suspension list above is what Brooks Performance told me they did when the car was there.

 

[carfax]

the shocks and sturuts are stock, and if you are wanting to do weekend runs at the track i wouldn't move the battery in the back just maybe put a light weight one in the front. i would get a irs brace soon just for protection. the stock irs is very strong but will break when not launched right.

if you are not planning on putting the car on the track every weekend i wouldnt put a adjustable shock on it. the bilsteins are a good variable shock but the problem will be the spring weight to get the car to transfer weight to get a good 60'.....but you will have some mph though.

 

[IronTerp]

yes i know all about how to make a irs work at a drag stip. i priced out irs parts and straight axle parts...irs just seemed ridiculous to keep when the irs will eventually break again. plus, when a mustang is basically a factory 4 link why keep a "bolt" in irs.

Well, that's all well and good, but when you make a comment like this: "i honestly think if you stick with the irs for drag racing your still going to be fighting it for the whole time." it's doing a disservice to the original poster by giving him false information. It doesn't take much to make an IRS perform safely at the track and just switching to an SRA is not necessarily a solution for many of us. Tires is the most critical addition to the the durability of an IRS setup anyway......

Daveman, the adjustable shocks and struts will have a small dial at the base of the cylinder. Changing over to these will be an excellent addtion to anyone that wants to hit the drag strip, go on easy cruises, or be challenged by some twisties. QA1 10-way adjustable shocks are very popular for the rear of our cars and will certainly help with weight transfer if adjusted properly. I've run these for 5 years with good resutts. There's several good options for adjustable front struts and while Tikico 5 ways are nice, they can be a bit pricey. The QA1 adjustable struts are notas popular as their shocks offerings. I've been running Strange Engineering 12 way adjustables for 2 years no and like them.

And the Odyssey battery series will save you about 22.4 lbs off the front end and is a big help in weight transfer.

 

[x NOODLES x]

And the Odyssey battery series will save you about 22.4 lbs off the front end and is a big help in weight transfer.

Can I get link on where to buy this? I just haven't done it.

:beer:

 

[IronTerp]

Can I get link on where to buy this? I just haven't done it.

:beer:

Here's one option: The 680 is the one most of us go with. You will need to by the terminals and the mounting box as well, but is a real clean setup.

Odyssey Battery PC680 - Odyssey Drycell Batteries

 

[x NOODLES x]

Thanks!!

:rockon: :beer:

 

[DaveMan]

I'm just worried about the low CCA of those batteries. How do they work, as in does the engine roll over slower then with the stock one? It gets pretty chilly here sometimes lol

 

[IronTerp]

I'm just worried about the low CCA of those batteries. How do they work, as in does the engine roll over slower then with the stock one? It gets pretty chilly here sometimes lol

I've had mine for 3 years with zero issues. Starts right up every time and at the track will power my IC in the pits for 30+ minutes and start right up for the next run.

 

[carfax]

Well, that's all well and good, but when you make a comment like this: "i honestly think if you stick with the irs for drag racing your still going to be fighting it for the whole time." it's doing a disservice to the original poster by giving him false information. It doesn't take much to make an IRS perform safely at the track and just switching to an SRA is not necessarily a solution for many of us. Tires is the most critical addition to the the durability of an IRS setup anyway......
QUOTE]


in all honesty how is that false information...the bolt in irs is basically junk.. period end of story. switching to a sra is not a solution? then what is putting around 3 grand in a irs that will break again or putting 3 grand in a sra that will basically be bullet proof. i just dont see anylogic in people putting all the money in a irs which is 150+ pounds more then the sra and can get better 60' with it while the just "drag race" the car.

he asked a opinion and i answered. no harm no foul.

 

[IronTerp]

$3,000???? Wow..........since you seem to have the answers, I'll just let this one go.

FYI, here's the cost of my rear suspension mods that have helped me at the track for the last 5 years:

IRS bushings..................$50
IRS Brace......................$150
IRS "Mathis" Brackets.......$100
Spare Half Shaft.............$100

 

[Derek@Amazon]

$3,000???? Wow..........since you seem to have the answers, I'll just let this one go.

FYI, here's the cost of my rear suspension mods that have helped me at the track for the last 5 years:

IRS bushings..................$50
IRS Brace......................$150
IRS "Mathis" Brackets.......$100
Spare Half Shaft.............$100

dwight....

he's right SRA is the answer for drag racing... im not getting into any of the cost or anything. but how many IRS cars have dipped into the low (not 1.39 and 1.38's im talking sub 33's) 1.30's and 1.20's in 60'.

edit:::

dont get me wrong you can make the IRS work to a point but your limited because of the aftermarket. there is no way to make it as strong as a 8.8 SRA or a 9" plus its a HUGE weight reduction.

you build up a crazy ass car with an auto there is very very little chance its gunna take many hits off a transbrake or if you prefer to stick with a stick it wont take many launchs sidestepping the clutch.

 

[DaveMan]

This is all great but doesn't really apply to my. I'm only looking to run consistent 11.50s because I don't want to put a roll bar in the car.

 

[Derek@Amazon]

This is all great but doesn't really apply to my. I'm only looking to run consistent 11.50s because I don't want to put a roll bar in the car.

then stick with the IRS... get a set of IRS bushings and some good shocks and springs in it. anything you can do to prevent wheel hop will go a long way.

looks like you have most of what you need already... id pull the bilstiens for a set of QA1's or strange shocks.. as for the tires, i dont think you really need the 11.50's but it wont hurt. you dont need a huge tire to get a car down the track.