Category Archives: Tech

Technical discussion and articles from the staff of Modern Performance.

Turbo Fiat 500 Black headlight/taillight/turn signal part numbers

We own a 2013 Fiat 500 Abarth and we’re not happy with the chrome headlights/turn signals/taillights. So, we bought all of the headlights/turn signals/taillights off of the 2013+ Fiat 500 Turbo model.


Fiat Turbo model black lights

Fiat Turbo model black lights

Now, these are NOT cheap. In fact if you visit your local dealership this entire set of lights may end up costing you close to $850-900 as of 6/1/13.

But, sometimes when you want the look, you just have to do it!

Anyways, we’d like to help out anyone else wanting to get the Turbo black lamps by listing the part numbers below.

Mopar/Fiat part number
68172231-AB headlight
68172230-AB headlight
68172246-AA front turn signal
68172247-AA front turn signal
68172251-AA tail lamp
68172250-AA tail lamp

Use those part numbers above to order with your local dealership.

New part for Dodge Dart 1.4 Turbo coming into stock shortly- MPx ported throttle bodies!

In studying the Dart 1.4, we found that the stock throttle body necked down a decent amount in the throttle body bore.

So, we studied it further, and found there were several areas to improve on with the Dart tb.

That lead to us porting out a TB, using flush screws versus the factory huge screws, and we were able to improve flow by 15% through the TB, make MORE power and torque, AND improve throttle response.

We were able to gain 6 hp and 2 lbs of torque PEAK at the wheels with our test 1.4 Turbo Dodge Dart!

Pic of a MPx ported tb
Dodge Dart 1.4 Turbo MPx ported throttle body

Now, we’ll begin offering these next week, and these will be BRAND new MOPAR tb’s that we port, that you buy outright. No used TB’s will be sold to you! You then buy it, install it, and be happy!

Watch out for our official product announcement next week!

03-05 SRT4 owners – removing your airbags, or airbag seats ? Read this.

Today we had a customer order one of the airbag delete trays and he was concerned that the airbag light would come on in his instrument cluster.

From doing some research, we have found that if you install a 1/8th watt 2 ohm resistor, that the resistor will lower the voltage output going back to the pcm, and therefore the check engine light wont come on.

This will also work for someone who is removing their airbag seats to put in the non airbag, SRT4 viper style seats as well.

How to: Adjusting the AGP Wastegate Actuator on a 2003-2005 Dodge SRT4/2008-2009 Caliber SRT4

If you’ve bought a AGP Wastegate actuator for your 2003-2005 Dodge SRT4 or 2008-2009 Dodge Caliber SRT4, here are a few quick tips on how to adjust the wastegate actuator after you’ve installed it.

Photo of AGP Wastegate actuator installed :
Adjusting a AGP Wastegate Actuator on a Dodge SRT4

First, for this you’ll need a 7/16 open ended wrench or 11mm open ended wrench. Now, in order to adjust the AGP wastegate you’ll first loosen the locknut which is locking the wastegate arm into place. Then you can make adjustments to the welded nut on the shaft.

We recommend you first rotate the arm with your fingers until you can find where the rod starts to get tight, and the rod is starting to pull the wastegate flap closed. After you reach this point, you can rotate the wastegate arm a little more for more tension.

Now, if you want even more boost than what this setting has given you, you can rotate the arm TOWARDS THE FIREWALL as shown in the photo below.

Adjusting a AGP Wastegate Actuator on a Dodge SRT4

If you want LESS boost then rotate the arm AWAY from the firewall.

SRT4 stock axles versus SRT4 DSS Axles comparison

Because a SRT4 owner was asking about why he had green boots on his axles, and just for kicks, we decided to do a SRT4 stock axle versus DSS Driveshaft shop Stage 3 axle comparison.

This axle set has been redesigned to have a new inner CV with larger tripods and a new heat treat on the female inner spline. The kit also has a higher durometer boot to seal the axle grease into the tripod assemblies.

SRT4 DSS Axle versus Stock Axle

SRT4 DSS Axle versus Stock Axle

Close up of FACTORY SRT4 AXLE splines:

SRT4 stock axle splines

Closeup of DSS SRT4 Axle Splines

DSS SRT4 axle splines

SRT4 Piston bore specs/compression specs

Ok guys, the reason we are posting this, is due to a customer ordering some custom pistons and screwing up the measurements. Now we have a tricky situation where a customer told us the measurements of what he wanted, we had made with JE and now we have a set of custom non usable pistons! So, heres some tech on piston/bore specs..

For the record – when pistons are refererred to as overbore, the measurements are typically in inches, not millimeters.

Stock bore size of a 03-05 SRT4 : 3.445 inches.

When a piston is 20 thousandths overbore, that means, that the piston would be sized roughly 3.465 inches instead of 3.445.

I hope this bit of information helps someone out there!

Explanation of spark plug heat ranges

We sell stock heat range, as well as colder range plugs for several different vehicles and we get asked This explanation is from our friends over at NGK.

A spark plug’s heat range has no relationship to the actual voltage transferred through the spark plug. Rather, the heat range is a measure of the spark plug’s ability to remove heat from the combustion chamber. The heat range measurement is determined by several factors; the length of the ceramic center insulator nose and its’ ability to absorb and transfer combustion heat, the material composition of the insulator and center electrode material.

NGK Spark plug heat ranges explained

The insulator nose length is the distance from the firing tip of the insulator to the point where insulator meets the metal shell. Since the insulator tip is the hottest part of the spark plug, the tip temperature is a primary factor in pre-ignition and fouling. Whether the spark plugs are fitted in a lawnmower, boat, or a race car, the spark plug tip temperature must remain between 500C-850°C. If the tip temperature is lower than 500°C, the insulator area surrounding the center electrode will not be hot enough to burn off carbon and combustion chamber deposits. These accumulated deposits can result in spark plug fouling leading to misfire. If the tip temperature is higher than 850°C the spark plug will overheat which may cause the ceramic around the center electrode to blister and the electrodes to melt. This may lead to pre-ignition/detonation and expensive engine damage. In identical spark plug types, the difference from one heat range to the next is the ability to remove approximately 70°C to 100°C from the combustion chamber. A projected style spark plug firing tip temperature is increased by 10°C to 20°C.

Difference in types of electric fans – puller vs pusher type

Today we had a call from a customer who asked what the difference was between a puller type and a pusher type electric fan was. Even though most of you will probably only be using your factory radiator fans, heres an explanation of the difference in type of fan – puller versus pusher type of aftermarket fans.

What is a “puller” fan?
A puller fan is a fan that is installed behind, or in back of the radiator, and wired so that when it is running, the air is “pulled” through the radiator core.

What is a “pusher” fan?
A pusher fan is a fan that is installed ahead, or in front of the radiator, and wired so that when it is running, the air is “pushed” through the radiator core.

Have a 95-05 Neon or 03-05 SRT4 that needs manual transmission servicing/parts ?

NOTE: we don’t sell transmission synchros, or other transmission rebuild component, or rebuild them. We’re only providing a contact and info for Mr Ed Peters who can rebuild your SRT4 transmission.

Have a 95-05 Neon or 03-05 SRT4 that needs servicing/parts ?

Is your Neon have synchro problems ? SRT4 have shifting problems or synchro issues ?

Typically most owners will go to a local transmission shop, or to a local dealership for service. However, most service places dont have the
tools to remove the casings, or remove the gear sets from the transmission. IF they can somehow manage to remove the neccesary parts, frequently they
cant get the service parts to fix the problem!

We have a retired Chrysler engineer friend who does a lot of Neon racing and has a huge supply of synchros, needle bearings, gears, etc to rebuild transmissions from the 95-99 Neon, 00-05 Neon and 03-05 SRT4’s with manual transmissions.

If your interested in getting a few manual transmission pieces for your transmission rebuild, or if you’d even consider having your whole transmission rebuilt for your 95-99 Neon, 00-05 Neon, and 03-05 SRT4 then contact Mr Peters at Because Mr Peters is retired, its best to contact him through email.

DO NOT CONTACT HIM IF YOU HAVE A DIFFERENT VEHICLE THAN THE ONES LISTED ABOVE, OR IF YOU HAVE AN AUTOMATIC TRANSMISSION. The services he offers are only for the cars listed above, and ONLY for manual transmissions.

Here is a photo of two finished 03-05 SRT4 transmissions that Mr Peters had in his truck when he stopped by our office last week.
Remanufactured 03-05 Dodge SRT4 transmissions

Heres a picture of several core transmissions Mr Peters picked up from us
Remanufactured 03-05 Dodge SRT4 transmissions

MPx Boost Leak Testers now in stock! A MUST have for all turbocharged car owners!

Have you ever experienced any of these situations with your turbocharged car?

– Had less peak boost than you had a few months ago ?
– Does your car seem a little bit slower ?
– Ever wonder if you could have a leaking pressure pipe in your engine?

If you’ve answered yes to any of the above questions, then this device could come in very handy.

MPx Boost Leak Testers for Turbocharged vehicles

This device is a piece of test equipment that will allow you to find out if there are any leaks from any hoses, clamps, cracked hosings that could be leaking boost.

The boost leak tester is a very simple piece to use, you simply remove the intake tubing to the turbo, and then clamp on the boost leak tester onto the turbo inlet. Then pressurize the turbo and piping with a air compressor or bicycle pump. This will fill the piping with compressed air and will allow you to listen for any leaks.

The MPx boost leak tester is made with a silicone rubber coupler for secure sealing to the turbo, uses a aluminum machined end cap, and a pressed in brass threaded tire valve.

Here is a photo of the boost leak tester attached onto a SRT4 motor with a factory turbo. Here you can see it simply attaches onto the turbo and is held in place with a hose clamp.

MPx Boost Leak Tester for Turbocharged vehicles

Headlight comparison for 03-05 Neon and SRT4 owners

I talked to a customer with a 2003-2005 SRT4 today that asked me:
“Whats the difference in all of the headlights you offer?”

So, I thought it would be good to take some photos and show the difference between the different models of headlights we offer and explain some of the differences.

First, heres the lineup of headlights we will be discussing today. From left to right, we have the Depo Factory style headlight, the Depo Projector style headlight, and the Halo Projector style headlights.

03-05 Neon/SRT4 headlight comparison

Here we see the backsides of the headlights, from left to right, the Halo Projector style headlights, Depo Projector style headlights, and Depo factory style headlights.

03-05 Neon/SRT4 headlight comparison

Here we have a backside closeup view of the Depo factory style headlight. The main plug in the center is the headlight plug, and the turn signal receptacle cannot be seen, off to the side.  The Depo factory style headlights have headlight bulbs, and turn signals preinstalled, ready to go. It also has factory style adjustments for light adjustment.

03-05 Neon/SRT4 headlight comparison

Here we have a backside closeup view of the Depo projector style headlight. The Depo projector light has a headlight bulb, and turn signal bulb preinstalled. The adjustment for light output is quite a bit different, and harder to adjust than a factory style light because youll need to remove the light to make adjustments to heigth of the light output.

03-05 Neon/SRT4 Depo Factory Style headlight

Here we have a backside closeup view of the Halo Projector style style headlights.This light is the most complicated headlight out of the three, because you have seperate wiring for the turn signals and halo lights that need to be connected. It comes with a bulb and wiring for the headlight, and its ready to connect. The turn signal bulb is not preinstalled, and you have to transfer the bulb and socket wiring from your factory headlight over to this one (thats easy). For those of you thinking about getting this headlight, even though it looks intimidating, dont worry as we include a 8 page installation instruction set with each headlight purchased at MP.

03-05 Neon/SRT4 Depo Projector Style headlight

Having shifting problems with your 95-05 Dodge/Plymouth Neon with manual transmission ?

Having shifting problems with your 95-05 Dodge/Plymouth Neon with manual transmission ?

We get calls often at Modern Performance from 1995-2005 Dodge/Plymouth Neon owners who have problems getting their manual transmission into gear, or even into reverse.

Sometimes, these problems can arise from shifter problems, but a very high percentage of Neon owners have problems with their manual transmission shift linkage bushings.

To better understand explain the problem, lets start out with the basics. Every manual transmission Neon has a shifter assembly inside the car, and two shift linkage cables attached onto it. The shift linkage cables go through the firewall and attach onto the transmission. The shift linkage cables are made out of steel, but the end of the shift linkages have rubber bushings that fail over time. Over time, your shifter will start to feel more and more mushy, and it will be more difficult to get the transmission into gear.

Heres a photo showing the shifter and the cables which are under the center console. The shifter bushings are pointed to in red, and the shift linkages are pointed to with yellow arrows.
95-05 Dodge/Plymouth Neon Manual Transmission shift linkage and bushings

Now, if you go to the dealership and try to buy replacement bushings, they arent sold seperately so you have to buy new shifter cables which will cost $130+! The solution to fix this, is with a product called Booger Bushings. Booger bushings are a set of four bushings that replace the two shifter bushings inside the car, and the two shifter bushings on the transmission.

Here are the Booger bushings:
Booger shift linkage bushings for the 95-05 Dodge/Plymouth Neon

Here is a photo of the same shifter above, with the Booger bushings installed on the shifter assembly.
Booger bushings installed onto a 95-05 Dodge Plymouth Neon

Here is a photo of the transmission with the booger bushings installed.
Booger bushings installed on the transmission of a 95-05 Dodge Plymouth Neon

Link to booger bushings on our website for more details:

Just for fun, heres a photo of a Neon where the shifter bushing disintegrated and fell off the car. This Neon still drove, but the driver would have a very hard time getting the car into gear!
95-05 Dodge Plymouth Neon with missing shift linkage bushing

Link to booger bushings on our website for more details:

Teardown of both car’s interior, and motor for the swap

Its time to start the teardown of both cars. The motor, interiors will be pulled in preparation of the swap.
Lots of photos are being taken in this stage, measurements are being made of the engine bays to measure clearances as well.

SRT4 into 95 Neon swap

SRT4 donor car’s dash is completely removed, steering column removed.

SRT4 into 95 Neon swap

Both the 2.4 all motor engine with transmission, and the SRT4 motor with transmission are pulled at this point and sitting near the rear of the Neon.

SRT4 into 95 Neon swap

Its pretty scary to see the entire Neon dash torn apart.

SRT4 into 95 Neon swap

SRT4 engine/trans on the left, old engine/trans platform (2.4 all motor) on the right.

SRT4 into 95 Neon swap

The new powerplant. This should give at *LEAST* 35 more horsepower at the wheels, and about 50 lbs of torque MORE than the older engine (power quoted at the wheels, not at the engine!) It will be fairly easy to produce 70 more horsepower and about 100 lbs of torque more at the wheels than the older setup with the SRT4 motor. That will make a HUGE difference in such a light car as the 95 Neon.

Future home of the 04 SRT4 motor and transmission.

SRT4 into 95 Neon swap

Piles of Neon and SRT4 parts are all around.

SRT4 into 95 Neon swap

95-99 Neon Enthusiasts will recognize a lot of the parts in this pile.

SRT4 into 95 Neon swap

SRT4 into 95 Neon swap

One of our two mechanics who are making this project happen. This is Fuey (pronounced Foo EE) who is one of the best fabricators /installers in Houston.

SRT4 into 95 Neon swap

Hondata Intake Manifold Heatshield gasket for 95-99 Dohc Neon, 03-05 SRT-4

One part that customers arent familiar with, and is frequently overlooked in a car buildup, is the Hondata intake manifold heatshield gasket. We carry it for the 95-99 Dodge Neon Dohc engine, and for the 03-05 SRT-4.

Here we have a photo showing the Hondata gasket on top, and the factory 03-05 SRT4 gasket on the bottom.

Hondata Intake Manifold Gasket for 95-99 Neon, 03-05 SRT4

As you can see in the photo above, the gaskets are identical in size. The difference, is in the material, and thickness of the gaskets.

The factory 95-99 Dodge Neon Dohc and 03-05 Dodge SRT4 both have aluminum intake manifolds that absorb a LOT of heat from the engine cylinder heads, therefore heating up the incoming air into the head. This can make a difference in as much as 3-4% of your cars horsepower, because the hotter the incoming air, the less timing, boost pressures your pcm will allow into the engine.

Sound like hogwash ? Well, think back to a day where it was cool, say 60-70 degrees outside with low humidity, and think about how great your car ran that day. Next, think about how your car ran at 90-100 degrees. Theres a NOTICEABLE difference in power! Thats because the pcm makes adjustments based on the incoming air temperature, so if you have a way to keep your incoming air cooler, then youll make more power !

Hondata Intake Manifold Gasket for 95-99 Neon, 03-05 SRT4

The Hondata gasket keeps the air cooler, by using plastic (great insulator) thats 3 times thicker than the factory intake manifold gasket which is made out of a paper type material.

Hondata Intake Manifold Gasket for 95-99 Neon, 03-05 SRT4

The gasket material is thick enough to help insulate from heat, HOWEVER, its not too thick where you wont be able to reuse your factory bolts! You can use the same factory bolts, and it will seal just as well, if not better the intake manifold to the head. We have had cars with 25+ psi of boost that have not had any leaks with the Hondata!

For more details and photos, heres a link to our website withthe Hondata listings: