Factory Service Manual(s):

They’re here…so use them.  Easy way to trace back wiring diagrams, wire color codes, connector pin outs, trouble shooting, steps to repair, etc.

SRT-4 Chassis manual:


SRT-4 Body manual:


SRT-4 Electrical manual:


SRT-4 Full service manual:


SRT-4 Transmission manual:



Spark Plugs/ignition:

The tried and true, go-to plug for every situation, and cheap. Good for stock hp levels all the way to 800+:

NGK 4306.

Some Feel like they need a different, or colder plug.  Iridiums are an option, a little more pricey and work just fine, as well.

1 step colder: NGK LZTR6AIX-13

2 step colder: NGK  LZTR7AIX-13

Rule of thumb is typically every 50-100hp you go one step colder, but rule of thumbs and real world doesn’t always align.  Stock heat range 4306 work great.

Plug Gap:

300-400: .035
500-600: .030-.035
700-800: .025-.030

‘Aftermarket’ coilpacks and wires are a bit overrated in my opinion.

Go to your local Autozone or O’reilly and purchase a coil pack with a lifetime warranty when yours wears out.  I went Deep 10s on an O’reilly coilpack, and have exceeded 40+psi plenty of times, without ever having an ignition miss.

Our wires are so short, that honestly, most of any ‘improvements’ in wires, are purely marketing.  Buy your local auto parts store’s lifetime warranty wires.  Otherwise, Granatelli, Taylor, and MSD make great wires.

Transmission Fluid:

Look, I know there’s the video floating around of a certain failure analysis engineer recommending HM 5w-30 engine oil for your transmission…but don’t fix a band-aid (atf) with another band-aid substitute by using engine oil.

Put some high quality manual transmission fluid in your car.  You’re willing to spend thousands in performance mods, but not an extra $10-20 for quality fluid.

Best MTF formulation that works for synchro based transmissions, IMO, is Torco MTF.  These cars are 10+ years old.  Protect your gearset, synchros, blocker liners.


Engine Fluid:

Without doing oil sample analysis tests of today’s oils, I can’t say anything about which “shelf” oil is the best or not.  4-5 years ago, someone did a test, and the Shell Rotella stuff had some of the highest Zinc PPM counts compared to all of the other big name oil stuff.  Zinc is great for protecting your motor against metal to metal contact…ie in the cylinderwall/sideskirts, bearing journals, rod journals, piston pins, etc.

I run 5w-40 full synthetic Rotella T6.  It’s worked for me at 500 to 900hp.  No reason it can’t for you.

For those that run to HM Mobil1 or what have you, I’m sure you’re just fine.  Alternatively, you can get Zinc additives in a bottle at your local auto parts store, and add ½ a bottle to your engine oil as well to gain some motor protection.

Worth noting, keep the oil weight to 5w-30 or 5w-40 if you are stock oil clearances.  Those clearances are there for a reason.

If you’re “built”, ask your building for bearing clearance specs, and their recommended oil weight.  Don’t go just putting 20w-50 in your car for no reason other than ‘you’re running big hp’.  You can do more harm than good.

Additionally, for extra oil filtration capacity, srt owners can also do a “big oil filter” mod.  You end up deleting the oem oil filter, stacking 3 oem oil filter housing gaskets, and using a larger sized oil filter from a different vehicle (5.0 mustang)

Here is a listed how to with part numbers:


Alternatively, you can buy the ‘kit’ from MPX:

Fuel System:

I’ll make it easy.  With today’s tuning devices, it is easy to scale injectors and make it work with almost any configuration.

1000cc injectors – 450-480hp max on ethanol

1300cc injectors – 550-600hp max on ethanol

1600cc injectors – 7xxhp on ethanol

2000cc injectors – 800-850hp max on ethanol

Stock turbo or turbos up and to about 52mm turbos, 1000s will suffice.

1300s are a good option for the 55-58mm turbo guys.

1600s will match well with 62-67mm.

2000s will match well with 62-67mm.

Things to note:  Many tuners will recommend 1600s over the 2000s due to 1600s having stainless internal bodies.  Why?  Ethanol is corrosive and hard on your fuel equipment.  2000cc injectors don’t have stainless internals, and thus they are more prone to getting clogged, ‘stuck’, and have affected spray pattern over time due to e85.  Please get your injectors cleaned at decent intervals.  It is too easy for a clogged injector to ruin a motor.  No issues to note with other injectors on e85.

Brands to use:

ID, FIC, FID.  Those 3 are all ‘Bosch’ based injectors.  You are getting the same exact fuel injector from all 3 companies…the only difference is how and why they flow match their injector sets.  You need to figure out if the additional cost(s) are worth the possible improved idle and/or fuel trims or not.  Consult with your tuner.

Stay away from: RC Eng, Five-0.

RC is outdated technology.  Most of the used sets floating around the community were from back in 2004-2008 before more options were available.

Fuel lines:

In the end, I rather just buy once, and do it right.  No, you will never choke out a -6an fuel hose in any circumstance, but for a few dollars more you can just go slightly bigger, and never have to worry about upgrading.

-8an feed, -8an return.  -10/-10 too, but -8an is sufficient for pretty much 100% of the folks out there.

Be sure to buy e85 compatible fuel line.  Don’t buy push-lok hose.  It’s cheap junk that dry rots quickly.  PTFE works great, but it is a bitch to utilize.

Summit e85 hose: https://www.summitracing.com/parts/sum-240820b/overview/

Jegs:  https://www.jegs.com/p/JEGS-Performance-Products/JEGS-Pro-Flo-350-Series-Nylon-Black-Braided-Hose/761335/10002/-1

You’ll need about 25ft or so to do a full return line.  Put the fuel regulator after the fuel rail.

I like Magnafuel for fuel components.  Their regulators are great, and are a step above the typical aeromotive stuff you get when you buy typical returnline kits

Magnafuel -8/-6 regulator:


For those with really big injectors, really big fuel pump(s), high fuel pressures, etc

E85 Safe Fuel Sender:

If you’re running E85, there’s a good chance your oem fuel level sender is going to go out.  What’s that mean to you?  Your fuel gauge will sit dead at E or just plain ol’ read incorrectly.

The fix:  You need a e85-safe fuel level sender. You will need to drop your fuel tank and pull out the fuel pump canister and replace the unit.  3 main options:

FueledbyMatt – Matt Cresto



Robert Spata


duration @ .050: 172/175
Valve Lift: .327/.261
LSA: 113

2.0L Neon
duration @ .050: 174/173
Valve Lift: .347/.315
LSA: 110 int: 108 exh: 112

Brian Crower
Stage 2
duration @ .050: 203/201
Valve Lift: .350/.310

Stage 3
duration @ .050mm: 211/203
Valve Lift: .389/.383

Stage 4 (direct copy of Crane 18)

duration  @ .050: 212/213

Valve Lift: .399/.399

Crower 2.4
Stage 1
DURATION @ .050: Int: 210°/Exh: 203°
Valve Lift:Int: .410” / Exh: .393”

Stage 2
DURATION @ .050: Int: 218°/Exh: 210°
Valve Lift: Int: .425 / Exh: .410

Stage 3

DURATION @ .050: Int: 230°/Exh: 222°
Valve Lift:Int: .449” / Exh: .433”

duration @ 1mm: 200/200
Valve Lift: .354/.354LSA: 110

duration @ 1mm: 204/204
Valve Lift: .364/.364

duration @ 1mm: 204/196
Valve Lift: .364/.354
LSA: 110

duration @ 1mm: 208/208
Valve Lift: .374/.374
LSA: 110

duration @ 1mm: 216/216
Valve Lift: .394/.394
LSA: 112


BC Stage 3 and 4
Crower 2.4: stg1 and up
Crower 2.0: stg1 and up
Crane 16’s and larger

This seems to be one of the top most uneducated areas of performance parts in the srt-4 community.  Firstly, you need to realize throwing the biggest set of cams into your car as possible, doesn’t correlate to the making the most hp possible.  If your turbo, intake manifold, head design package, and exhaust manifold all aren’t built for, and capable of flowing the hp those ‘big cams’ you just ordered, in the rpm range that it needs to shine, then guess what?  You are severely hurting 98% of your powerband in hopes of having a slight hp gain at the tippy top peak of your rev limit.  Most cases, total average hp over the powerband is going to win the race, almost every time.

The srt-4 community is long known for over camming their under-built setup…don’t be one of them.

That said…what cams for what?

Stock turbo:

You really don’t need cams for a stock turbo.  You can max it out long before the cams are ever an issue.  If you want a little extra bump… Brian Crower Stage 2 are a great mild street option that will get mild gains through the entire powerband.

Stage 3:

This turbo is hard to beat on the street.  Instant spool, and capable of doing 400+hp/450tq and looks stock.  Worst thing you can do is over cam this application, and ruin the characteristics of this turbo for the sake of trying to make peak power where it’s big turbo counter parts will shine over it every time.  Again, total average hp is the name of the game here.

BC Stage 2 for a mild basic DD cam setup.  Otherwise Brian Crower stage 3 or Crane 16s are a good fit, and is about as large as you want to go on this.

50-55mm (400-550hp range):

These turbos are going to make peak power at 5600rpm almost every single time, on stock cams.  And after that?  Downward decent all the way to redline.  Help that out, and put in a Brian Crower Stage 3, Crower Stage 1, or Crane 16.  Rev these cars out to 62-6400rpm max.  Zero point to go further.

58-62mm (550-650hp range):

Now we’re stepping up in power.  Make sure your head has some headwork…intake manifold ported, bigger throttle body, etc.  These turbos will want to sing a little higher in the rpm range, so we need to make sure the efficiency of the motor package can keep up.

Crower Stage 2 is my go to cam for most any 5-700hp set up.  You will sacrifice a little idle quality (ie; lope for you lope nutswingers), but you get an improved powerband in the mid-top end range of the rpms, and not hurt spool too badly in the process.  Alternatively, you can also run Crane 18s as well.  These cars will typically rev to 6700-7300.  DYNO IT.  No need to rev to 700-7500 if the hp is dropping like a rock.

62mm-67mm (7-800):

For the 64 and 67mm (and the select few all out 62mm guys wringing those turbos out), You’re likely revving it to 7200-7800 range.  If you properly selected the turbo based off of actual real world realistic plans of making 7-800+hp, and not just dreaming of your favorite facebook build to duplicate, you’re going to want to have a larger set of cams to make sure the power doesn’t start signing off early.  Please make sure you have all the appropriately matched parts.  Big turbo, huge cams, and stock flowing components is a disaster of a setup.  Efficiency is key.

Crower Stage 2 for the street/strip weekend warrior guys.  Crower Stage 3 for the guys that are willing to sacrifice 300rpm spool, a huge drop in midrange power, and only gain in the top end, over the Crower Stage 2’s.  They’re pretty much a drag/race cam only, and I see WAY too many people selecting the CS3 for no reason other than either improperly educated, or just want retarded lope.  There is nothing fun about that after your 3rd time showing it off to your friends in at your weekly car meet.  Function > Form

Turbo Sizing:

There are so many options out there, for me to do a write up on this would be entirely exhausting, and would end up into a 10 page essay. You need to do your hw.  I will give you some guidelines:

When speaking turbo size in MM (millimeter), 99.99% of the time we are speaking about compressor wheel inducer sizing, and turbine wheel exducer size.

Example:  Precision 6266… 62mm compressor inducer size, 66mm turbine exducer size.

Here is a pretty extensive list of most modern turbos with their relative wheel sizes:


Here’s my rough guidelines for turbo selection…these numbers below are compressor inducer mm sizes (pretty much the go-to when you are stating your turbo is “XXmm”).  Bigger turbo doesn’t mean more power if you don’t have the flow components or rpm to allow it to work efficiently.

400-500: 50, 52, 55mm

500-600: 55, 58, 62mm

550-650: 58, 62mm, 64mm

600-700: 58, 62, 64mm

650-750: 62, 64, 67mm

750-800: 64, 67mm

300whp Stock turbo:

Lets not make this any more difficult than what it needs to be

1000cc injectors

Fuel pump (walbro 450, 044, aem/dw 340 all good options)


3” 02

3” down pipe

Your favorite vendor’s wastegate

3bar map and tip

Diablosport predator/intune or HP Tuners tune

E85 or race gas

Proven to get you to 300whp/upper 300-400tq by 21-24psi…relatively easy. No port work, or cams necessary.

A modified exhaust manifold will make the road to 300whp way easier.  Not to mention increased the longevity of the turbo’s life span by decreasing the heat that thing has to endure.

Modified exhaust manifolds include portwork, external wastegate, and/or cutting off the narrow/small neck right after the scroll, and replacing it with a 2.5” outlet tube.  Matthew Floyd and Turbobay offer these services.

External wastegate doesn’t increase boost potential, but you are looking at a decrease in back pressure, decrease in turbulence, and an increase in hp from keeping the exhaust coming out of the wastegate separate from the flow out of the turbine wheel.

450hp Streetable setup:

450hp hp is a ton of hp for a 2900lb fwd street, daily driven car.  It’s simple to do, and doesn’t take much…lets get right into it.
-AGP log manifold with their 2.5-3” 02 housing… alternative is a Treadstone log manifold.  Any other log style manifolds are cheap, and crack.  IDC what your friend’s cousin’s little brother told you.

-Fuel Returnline.  I prefer the regulator After the fuel rail for equal fuel distribution across all 4 cylinders

-Upgraded fuel pump.  Walbro 450lph, Bosch 044, AEM 340, all work here.

-3” exhaust…preferably no cat.

-4” bar and plate fmic.  The ebay ones work great for the price and up to 500-550hp.  Any other option like the MPX or AGP are great upgraded alternatives.

-Aftermarket coldside pipe with a bov.  I only recommend Tial bov’s.  IDC if you like the sound of a turbo xs, hks, or w/e ricer bov your friend uses. Tial’s flat out work and function the best.

-3 bar map and tip sensors.  They are cheap…like $50.  And you will need them in order to run more than 18psi.

-Tuning device.  Diablosport is pretty much the go to here.  Pick your favorite tuner…they change monthly on FB.

-quality high octane fuel of your choice.

-select a turbo to fit stock rpm range and engine characteristics… 50t was popular in 2003…and it’s still popular today…for a reason.  It flat out works.  It is a hard turbo to beat for stock block numbers.

Other turbo options:  5431 (billet 50t option), gtx 3071/76 ($$), 5831.

62mm will work, but it’s not ideal on a log manifold, and you will be sacrificing powerband a bit as well as max power potential since the log manifold will be maxed out before the turbo.

Tuning Options:

Lucky for you, we aren’t in 2006 anymore.  Long gone are the days of guys using map clamps and SAFC’s to trick the map sensor into thinking you’re running less boost so that it can supply less fuel…while an unfortunate bi-product was increased ignition timing as a result.

Now we have legitimate options where we can flash the stock pcm to do almost literally anything we want within it’s given limitations.  For up to 7-800hp, the stock pcm flashed, can really hold its own.

The stock pcm flash options are:

Diablosport (predator, intune, trinity)

HP Tuners

SCT…is also an option, but it’s basically dead in water, obsolete.

Kevin Sykes – Sykes Tuning

The diablosport handheld has limited end-user adjustability… 1k rpm increment fuel and timing adjustment, fan adjustability, and the fun stops there.  But this is a great option for the guys that want a PROFESSIONAL to tune their car, and all they have to do is upload it into their car, and either be done, or datalog it, provide feed back, and get revised tunes.

HPTuner can be used as the same method as the DS…but you can also purchase credits and have the ability to adjust and tune EVERYTHING within the stock pcm.  Look, unless you’ve had actual real-world stock pcm tuning experience, took EFI classes, and know what you’re doing, don’t do it.  The stock pcm has a ton of tables and modifies  and aside from the basic ignition and fuel map, you probably won’t have the slightest clue of what you’re looking at.  Leave it to a tuner.

Kevin Sykes released his own stock pcm tuning software.  He does his own programming, software creation, manufacturing of handhelds, etc.  Think of it like an HP Tuners, but his own rendition.  You get complete control of the stock pcm.  I don’t know much else about it, but search his name on FB and contact him if you are interested.

If you want to get off of the stock pcm and into a true, engine management system and reap the benefits that comes along with it, there are a plethora of options.  Lets just be frank though…going true EMS and NOT cutting corners, you’re going to be spending 3, 4, $5k quickly.  Don’t let these facebook hypemen sell you on any particular EMS product either.  One day they praise something, and the next they ride a different hype train and buy all their apparel with it.

Listen to your tuner, and go with what HE suggests.  The more comfortable he is with the tuning software, the better the results will be for you.

AEM V1 is plug and play, and works…but it is 15yr old technology, isn’t supported by AEM, and is obsolete.

Modern EMS options:

AEM Infinity

Megasquirt Pro, Ultimate, Evo.

Alternatively, for the budget conscious, MS3X will do 95% of the above MS options, for around $650 with a universal flying lead wire harness.

FuelTech FT500

Haltech Elite 1500 & 2500

Holly Eliminator

MAP & TIP Sensors

Putting the right map & tip on your car for a specific boost range is important.  MAP tells your pcm what your boost is so it can supply the correct fuel and timing.  Boost above your MAP’s max psi reading, and it won’t know what your car is actually boosting, and can cause dangerously lean conditions or worse.

TIP is basically a barometer sensor.  It is used as a modifier for when your baro changes (weather conditions and/or elevation changes).

If you buy a MAP sensor for your car, you need to buy another for your TIP.



OEM 2.25 Bar sensors: Reads up to 18.5psi

Mopar/Caliber 3bar sensors: Reads up to 29psi

3.5bar sensors:  Read up to 36psi

4bar sensors: Read up to 43psi

5bar map sensors:  Read up to 58psi

NOTE:  The larger the map sensors you run, the less resolution you are going to have on your timing/fuel tables in your pcm/ems.  So with that said, you want to run the lowest necessary map sensor required, so you can maximize your resolution capabilities.

3bar: Caliber sensors P/N 5149056AA

3.5bar: AEM, SSI, Innovate, Zeitronix, etc.

4bar: Brian P. Mcmahan on FB sells PnP 4 bar sensors.  Also Omni Power

5bar: AEM, SSI, Innovate, Zeitronix, etc.


If you street race, roll race, drag race, just like playing on your way to work, you need a WOT box (if you’re stock pcm that is).

Wired to your tach signal and clutch switch, this device cuts power momentarily to your ignition/fuel when you touch your clutch pedal.

What’s the purpose?
The WOT BOX allows you to keep your throttle/pedal planted to the floor and as the box is called…wide open throttle, shift.  The intermittent cut of ignition allows your synchros, sliders, and blocker liners to all slow down and engage at the same time. This means less chance for a mis-shift, less chance of grinding your gears, and an overall happier transmission when you’re slamming gears.

The benefit of being able to utilize a WOT box is you get to maintain your boost on each shift, where as if you were to lift to shift, your car loses all of its boost on each up shift, and has to rebuild boost.  You eliminate the need to rebuild boost, and thus helps cut down on your ET’s.

Additionally it also functions as a 2-step rev limiter.  For dig racing or drag racing, you can set the rpm up so that when 2step is activated, you can hold the throttle down to the floor, and the 2step will engage whatever rpm you have it set at, so that you can build boost at the line as well as launch more consistently since the limiter is held steady for you.

Recommended settings:

WOT:  You need to set up the wot/ignition cut based on your shifting ability.  The faster you can shift, the shorter the cut can be.

Don’t try to be a johnny force, and slam gears quicker than what your foot can keep up with (or vice versa).  Start out at 150-200ms, and work your way down.  You may end up at 75-100ms, or you may leave it alone.  Very few people need to set it to 50, let alone 25.  Also, you are decreasing the benefit of protecting your transmission components having it set that low, and it’s likely you aren’t shifting that fast to begin with.

2step:  In an ideal world, you typically want to set your 2step about 3-400rpm after PEAK torque.  That way when you drop the clutch, and the tires catch up with the rpm, you fall right around into peak torque, and that torque will help pull you out of the hole.  Look at your dyno sheet, and get an idea of where it needs to be.

Your results may vary, but those are pretty solid base settings to get you going.

10/10 mod, and almost every/any srt should have one.

MAX horsepower out of the stock block:

Look, you’re going to get 10 different answers from 10 different people…I’ll keep it simple.

440-460whp is about the max you want to go on the stock bottom end before it bites back at you.

Yes people have done 480, 500, and low 500hp…but those motors don’t last, or they did it purely to showcase a dyno number.

Horsepower is no fun if you put a hole through the block and are on jack stands for the next 6 months while you build a new motor.

Piston ring lands crack easy if you get a good amount of knock when pushing it.  The rods can/do bend with increased power.  The bedplate can/will crack or break with high tq or rpm.  This is the nature of pushing stock components over 2x their oem rated amount.

Drag Radial & Slicks:

For the Vast majority of srt-4 owners, the GO-TO drag radial size is a 235/60/15.  225/50/15 are too small diameter wise, and you will blow the tires off of them on almost anything above stock turbo capabilities.

Steel belted drag radials (think same tire construction as your street tires, but softer DR compound) will have better driving characteristics on the street.  You can stop, turn, and brake, for the most part, just fine.  They are likely to last a bit longer too.  If you’re the type that’s going to put drs on and just drive it everywhere, a steel belted DR is the better option.  CON:  You have a stiffer sideway, so you lose some ‘bite’ into the pavement, and thus less traction compared to it’s bias-ply counterpart.

Bias ply drag radials (think slick tire construction, with a basic tread pattern molded in) will almost always bite harder into the pavement due to the softer sidewall, and thus can provide more traction as it hooks into the road harder vs a steel belted DR. CONS:  Horrible driving characteristics.  Combine the soft side walls with the fact that they generally like less tire pressure than a steel belted dr, you are looking at a tire that can’t take corners well, wallows over bumps/waves in the road, and generally just a less safe tire.  Good choice if you are are bolting on to race for the night, and swapping back to a regular street tire, dig racing, and/or just looking for every last bit of traction.

M&H and MT both offer a 235/60/15 in a bias ply, and MT offers that same size in a steel-belted dr.  M&H runs slightly smaller in overall size compared to it’s competitor.

Other tire options are the 245/55/15 M&H and 26×9.5×15 Hoosiers.

I didn’t even mention 17” DRs…those options ARE out there…but sidewall height is not much, and half the equation of hooking a tire, is side wall construction.  Don’t waste the money.  If you want traction, get a 15” rim.


24.5×8.5×15 is pretty much the go to for 98% of the srt owners out there.The tire height is right, and it just plain flat out works.  M&H or MT both work well.

26×8.5×15 is also an option here.  Increased tire height results in increased roll out, and longer gearing.  Compared to a 24.5, it’s about 3-4mph longer in 1-2, and 7mph or so longer in 3-4, give or take.  For those that are OEM input shaft with the incredibly short 1st gear ratio, the 26” may be a nice option to give you a little more run out in 1st out of the hole.  Also for the bigger hp guys, you can also be able to apply a little more power to the tire, though in a drag strip situation, it’s not necessarily an issue.


Steelies work.  15×6. Cheap, and that’s about where the pros end.  Narrow rim width equals less contact patch on the road.

15×7 (typically 35-40mm offset), 15×8 (~30mm offset range), and 15×9 (15-25mm offset range) are what you want to use.  Obviously the wider the rim, the more rubber you can squeeze onto the ground.  15×9 vs a 15×7, you’re theoretically adding 4” of total width to your potential contact patch you’re putting to the ground.  Yes, that matters.

With our wheel pattern being 5×100, our options are severely limited on rim options.  Rota and Varrstoen/Road Force have/had some options. ‘Drag’ (the brand) also has a few rim options.

Bassett has some ‘steel’ rims that fit our car.  You will need 5.5” backspace, and you will likely need to run a 10mm spacer, or will need to grind your calipers for clearance.

Wheel & Tire Tech:

I’m not going to act like I’m a tire or rim expert for overall/every day rim fitment.  People far more educated in that genre have already spelled it out and did the homework, so that I wouldn’t have to.  Bone-apple-tea











Truth of the matter is BC, Megan, D2, and Ksports all look like they were manufactured by the same manufacturer overseas, and just anodize them different colors and with their own valving/spring rates.  The top plates all look the same, as well as the bodies.  BC has slightly better body build/material.

Get whichever ones you can get the best deal on, imo out of that bunch.  Good thing is, they come with front camber top plates, and the BC rear camber plates will work on any of those other particular units.

KW is the parent company of ST.  Quality from the both are pretty well touted, with the ST using cheaper metal for the bodies to help save the consumer some money.  KW is more known for their road racing background, and as such, for actual enthusiasts that like to take their cars through corners, instead of straight line, the KW/ST options may be a better route than the BC/Megan/D2/Ksport stuff.

Gecco is a new company that popped up in the last year.  I don’t know much about it, other than people are probably buying them because of the ‘cool’ green and purple anodization (marketing at its finest), lol.

Preload your springs properly per the manufacturer’s recommendation.

Preload is a great way to also increase the car’s ‘spring rate’ without having to go purchase new springs.

Preloading my coil springs beyond the recommended amounts effectively made the ~350lb rated stock springs ALOT stiffer.

These cars are old.  The rubber in the suspension bushings, if they haven’t been replaced already, are toasted. I guarantee it.

Aside from coilovers, one of the best things you can do is swap your oem LCA bushings for Prothane stiffer LCA bushings.  You will decrease wheel hop considerably, or even eliminate it, depending on other suspension components.

Other things to replace while you’re in there would be sway bar bushings, and rear trailing arm bushings.

They are cheap to buy, and all new bushings will honestly make the car feel brand new and handle completely better.


Now that we have your suspension in line, lets talk alignment.

Coilovers and drag radials are really key ingredients to making sure you can apply some power to the ground with your srt-4.  Issue is, people massively over look their alignment. Those sticky tires don’t mean much if your contact patch isn’t properly planted.

OEM FSM alignment specs:

CAMBER                                  0.00°
Cross Camber                          0.00°
CASTER                                 +2.60°
Cross Caster                            0.00°
TOTAL TOE*                          +0.20°
CAMBER                                 -0.25°
TOTAL TOE*                          +0.30°
THRUST ANGLE                     0.00°

For drag racing, you want the rears to have as little rolling resistance as possible!  Keep it straight as an arrow.

The front, when you’re under load, ideally you want the camber and toe to pull to 0.

Again, this is for straight line performance, and for a “daily driver” or turns, you will want a different alignment spec.

For better performance turning or for road course, I’m of no help, so ask your road coarse buddies!

Weight Reduction:

Next up, weight reduction.  Rule of thumb is 100lb = .1 off your ET.  Take into account driver error, that .1 may not matter.  You start shedding 2…3…400lb, then you’ll really start to make a difference, but then you’re also taking your awesome quick/high power daily driver, and making it into a loud, obnoxious, amenity-lost race car, that will likely not be a drag race queen, to make the effort worth it.  Just be conscious of your decisions, and don’t permanently ruin/remove something you might regret!

Stock Curb Weight: 2970# (per Dodge)
Distribution: 62% front 38% rear
Fuel Tank: 12.5 gallons

Removable Items:
AC system…………………….22.5*
Front Passenger Seat……….43*
Front Seatbelts……………….5*
Rear Passenger Seat………..10*
Rear Pass Seat Back………..30*
Rear Seatbelts………………..7*
Rear Deck Cover…………….10*
Trunk Carpet and Pads……..12.5*
Sound Deadening/Insul……..20*
Floor mats……………………..6*
Spare Tire and Hardware…..28*
CD Play………………………..4*
Passenger Air Bag……………7*
Driver Air Bag…………………3*
Head Liner…………………….2*
Side Windows………………….?
Heater Core/Blower……………?*
Variety-small trim stuff……….?*
Front Bumper…………………20
Total Listed savings……………262 lbs
Total w/moonroof removal…….288 lbs
*= NASA SRT class legal………263 lbs
Replaceable Items:
Item_____________Orig. Weight___New Wt.___Change__Total Redux
Wheels and Tires*………………44…………….32…… …..12…………48
Drivers Seat*…………………… 43…………….23………..20………….20
Hood ($900 race version)………30………………3………..2 7………….27
Deck Lid ($800 race version)…..23……………..3…………20… ……….20
Battery*………………………….30……… …….11………..19………….19
Springs/Struts (to C.O.’s)*…….20…………….14………….6. …………24
Brakes-front (TCE/Wilwood)*….11………………7………….4.. …………8
Brakes-rear (TCE/Wilwood)*………………………………….9 ………….18
Flywheel*…………………………..?…….. ……….?………….8…………..8
Exhaust*………………………….45……… …….18…………27………….27
Underdrive Pulley…………………?……………….?.. ………..?……………3 Radiator*…………………………..7…….. ………9.5………-2.5……..Damn!
Total……………………………………… ……………………………..219+ lbs
* Total (NASA SRT race class legal)…………………………………153+ lbs

Commonly used SRT-4 Tuners:

Below is a list of commonly used SRT-4 tuners for the DS and HPT stuff.  They can provide you email tunes and/or in-person dyno tuning in most cases.

In no particular order:

Nigel/BST (DS, HPT, EMS)

Matthew Cresto (DS, HPT)

Brian P. Mcmahan (Drag-on Tuning) (DS)

Rage-tek/Nemo (DS)

David Trojan (Duster 360) (DS)

Neil Nemiro (SCT)

Dan Zaruszak

[email protected]/Full Throttle Performance (DS, AEM)

Kevin Sykes-Bonnett (Sykes tuning device, DS)



Vacuum Line Configurations:

NOTE: If you’re stock PCM, ALWAYS keep the TIP Solenoid plugged in, and utilized like the picture below.  Others telling you to delete it and its not needed, are wrong.

OEM Configuration















Stock turbo + aftermarket BOV:

Remove the blue and pink lines.  You will no longer use the solenoid.  Tuck it away.

Run a line from the Intake manifold or Throttle body to your bov port.

Stock turbo + aftermarket wastegate:

Remove all lines associated with the ‘green’ solenoid.  You will no longer use the solenoid.  Tuck it away.

Run a line from compressor nipple port, to the port on your wastegate.

If you run an external wastegate, run it from Turbo > MBC > bottom WG port.

If you run an external wastegate + EBC, you need to look at the instruction manual and follow the diagram configuration since it varies from model to model.

Big turbo:

You will no longer use the green or blue solenoid.  Remove all lines associated with them.  Tuck it away.

Follow the diagrams associated with aftermarket bov + wastegate as above

Turbo > MBC/EBC > bottom wastegate port (top wastegate port may be used on some EBC configurations)

Intake manifold > BOV on cold side

Keep TIP solenoid and the 2 lines related to it.

Run line from Intake manifold to brake booster

Thats all there is to it!  Don’t over complicate things.

Fuel pressure regulator:

If you run a fuel pressure regulator/returnline…make sure to mount the FPR after the fuel rail to help ensure equal distribution of fuel across all four cylinders.

For boost reference, hook it to your intake manifold or cold side pipe.  CONSULT YOUR TUNER first.  He may want a vacuum source (IE; intake manifold/throttle body), or he may not require it (IE; cold side pipe then).

DON’T Tee the FPR line with any other line, just out of good practice.  Give it it’s own dedicated pressure source.

OEM Torque Specs:












OEM Engine Clearance Specs:

General Specification
Type In-Line OHV, DOHC
Number of Cylinders 4
Displacement 2.4 Liters
(148 cu. in.)
Bore 87.5 mm
(3.445 in.)
Stroke 101.0 mm
(3.976 in.)
Compression Ratio 8.1:1
Firing Order 1-3-4-2
Compression Pressure 1172–1551 kPa
(170–225 psi)
Max. Variation Between Cylinders 25%
Cylinder Block
Cylinder Bore Diameter 87.4924–87.5076 mm
(3.4446–3.4452 in.)
Out-of-Round (Max.) 0.051 mm
(0.002 in.)
Taper (Max.) 0.051 mm
(0.002 in.)
Piston Diameter 87.463–87.481 mm
(3.4434–3.4441 in.)
Clearance @ 22 mm (0.866 in.) from bottom of skirt (Turbo) 0.024–0.057 mm
(0.0009–0.0022 in.)
Weight 346–356 grams
(12.20–12.56 oz.)
Land Clearance (Diametrical) 0.614–0.664 mm
(0.024–0.026 in.)
Piston Length 61.43 mm
(2.419 in.)
Piston Ring Groove Depth No. 1 4.640–4.784 mm
(0.182–0.188 in.)
Piston Ring Groove Depth No. 2 4.575–4.719 mm
(0.180–0.185 in.)
Piston Ring Groove Depth No. 3 4.097–4.236 mm
(0.161–0.166 in.)
Piston Pins
Clearance in Piston 0.005–0.018 mm
(0.0002–0.0008 in.)
Clearance in Connecting Rod Interference
Diameter 21.998–22.003 mm
(0.8660–0.8662 in.)
End Play None
Length 72.75–73.25 mm
(2.864–2.883 in.)
Piston Rings
Ring Gap—Top Compression Ring 0.25–0.51 mm
(0.0098–0.020 in.)
Wear Limit 0.8 mm
(0.031 in.)
Ring Gap—2nd Compression Ring 0.23–0.48 mm
(0.009–0.018 in.)
Wear Limit 0.8 mm
(0.031 in.)
Ring Gap—Oil Control Steel Rails 0.25–0.64 mm
(0.0098–0.025 in.)
Wear Limit 1.0 mm
(0.039 in.)
Ring Side Clearance—Compression Rings 0.030–0.080 mm
(0.0011–0.0031 in.)
Wear Limit 0.10 mm
(0.004 in.)
Ring Side Clearance—Oil Ring Pack 0.012–0.178 mm
(0.0004–0.0070 in.)
Ring Width—Compression Rings 1.47–1.50 mm
(0.057–0.059 in.)
Ring Width—Oil Ring Pack 2.72–2.88 mm
(0.107–0.1133 in.)
Connecting Rod
Bearing Clearance 0.025–0.071 mm
(0.0009–0.0027 in.)
Wear Limit 0.075 mm
(0.003 in.)
Bore Diameter—Piston Pin 20.96–20.98 mm
(0.8252–0.8260 in.)
Bore Diameter—Crankshaft End 53.007–52.993 mm
(2.0868–2.0863 in.)
Side Clearance 0.13–0.38 mm
(0.005–0.015 in.)
Wear Limit 0.40 mm
(0.016 in.)
Weight—Total (Less Bearing) 565.8 grams
(19.96 oz.)
Connecting Rod Journal Diameter 49.984–50.000 mm
(1.968–1.9685 in.)
Main Bearing Journal Diameter 59.992–60.008 mm
(2.362–2.3625 in.)
Journal Out-of-Round (Max.) 0.0035 mm
(0.0003 in.)
Journal Taper (Max.) 0.007 mm
(0.0001 in.)
End Play 0.09–0.27 mm
(0.0035–0.0106 in.)
Wear Limit 0.38 mm
(0.015 in.)
Main Bearing Diametrical Clearance 0.018–0.062 mm
(0.0007–0.0024 in.)
Hydraulic Lash Adjuster
Body Diameter 15.901–15.913 mm
(0.626–0.6264 in.)
Plunger Travel Minimum (Dry) 3.0 mm
(0.118 in.)
Cylinder Head Camshaft Bearing Bore Diameter
Journals No.1–6 26.020–26.041 mm
(1.024–1.025 in.)
Journal Diameter No. 1–6 25.951–25.970 mm
(1.021–1.022 in.)
Bearing Clearance—Diametrical 0.069–0.071 mm
(0.0027–0.003 in.)
End Play 0.05–0.17 mm
(0.0019–0.0066 in.)
Lift (Zero Lash)
Intake 8.25 mm
(0.324 in.)
Exhaust 6.60 mm
(0.259 in.)
Intake Valve Timing*
Closes (ABDC) 44.3°
Opens (ATDC) 6.2°
Duration 218°
Exhaust Valve Timing*
Closes (ATDC) 1°
Opens (BBDC) 40°
Duration 221°
Valve Overlap 5.4°
*All readings in crankshaft degrees, at 0.5 mm (0.019 in.) of valve lift.
Cylinder Head
Material Cast Aluminum
Gasket Thickness (Compressed) 0.71 mm
(0.028 in.)
Valve Seat
Angle 44.5–45°
Seat Diameter—Intake 34.37–34.63 mm
(1.353–1.363 in.)
Seat Diameter—Exhaust 27.06–27.32 mm
(1.065–1.075 in.)
Runout (Max.) 0.05 mm
(0.002 in.)
Valve Seat Width—Intake and Exhaust 0.9–1.3 mm
(0.035–0.051 in.)
Service Limit—Intake 2.0 mm
(0.079 in.)
Service Limit—Exhaust 2.5 mm
(0.098 in.)
Valve Guide
Diameter I.D. 5.975–6.000 mm
(0.235–0.236 in.)
Guide Bore Diameter 11.0–11.02 mm
(0.4330–0.4338 in.)
Guide Height (spring seat to guide tip) 13.25–13.75 mm
(0.521–0.541 in.)
Face Angle—Intake and Exhaust 44.5—45°
Head Diameter—Intake 34.67–34.93 mm
1.364–1.375 in.)
Head Diameter—Exhaust 28.32–28.52 mm
(1.114–1.122 in.)
Valve Length (Overall)
—Intake 112.76–113.32 mm
(4.439–4.461 in.)
—Exhaust 110.89–111.69 mm
(4.365–4.397 in.)
Valve Stem Diameter
—Intake 5.934–5.952 mm
(0.2337–0.2344 in.)
—Exhaust 5.906–5.924 mm
(0.2326–0.2333 in.)
Valve Margin
Intake 1.2–1.7 mm
(0.047–0.066 in.)
Service Limit 0.95 mm
(1/32 in.)
Exhaust 0.985–1.315 mm
(0.038–0.051 in.)
Service Limit 1.05 mm
(3/64 in.)
Valve Stem Tip Height
Intake 48.04 mm
(1.891 in.)
Exhaust 47.99 mm
(1.889 in.)
Valve Stem to Guide Clearance
Intake 0.048–0.066 mm
(0.0018–0.0025 in.)
Max. Allowable 0.076 mm
(0.003 in.)
Service Limit 0.25 mm
(0.010 in.)
Exhaust 0.0736–0.094 mm
(0.0029–0.0037 in.)
Max. Allowable 0.101 mm
(0.004 in.)
Service Limit 0.25 mm
(0.010 in.)
Valve Springs
Free Length (Approx.) 48.4 mm
(1.905 in.)
Nominal Force (Valve Closed) 338 N @ 38.0 mm
(75.98 lbs. @ 1.496 in.)
Nominal Force (Valve Open) 607 N @ 29.75 mm
(136 lbs. @ 1.172 in.)
Installed Height 38.00 mm
(1.496 in.)
Number of Coils 7.82
Wire Diameter 3.86 mm
(1.496 in.)
Oil Pump
Clearance Over Rotors (Max.) 0.10 mm
(0.004 in.)
Cover Out-of-Flat (Max.) 0.025 mm
(0.001 in.)
Inner Rotor Thickness (Min.) 10.699 mm
(0.421 in.)
Outer Rotor Thickness (Min.) 10.699 mm
(0.421 in.)
Outer Rotor Clearance (Max.) 0.039 mm
(0.015 in.)
Outer Rotor Diameter (Min.) 85.924 mm
(3.383 in.)
Tip Clearance Between Rotors (Max.) 0.20 mm
(0.008 in.)
Oil Pressure
At Curb Idle Speed* 25 kPa
(4 psi)
At 3000 rpm 170–550 kPa
(25–80 psi)

CAUTION: *If pressure is ZERO at curb idle, DO NOT run engine at 3000 rpm.



All info taken from :




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