The Best Instructions in Aero
Every Street Aero part ships with a written installation manual for that exact part, and all 80 of them are free to download before you order anything. Seventy-five of the 80 are written for one specific year, make, model and trim.
We have seen aftermarket aero turn up with no paperwork in the box at all, or with one generic sheet showing a car that isn't yours. Neither is much help when you are under the bumper working out which way round a bracket goes.
So we write a manual per application. A front splitter for a 2016 Mustang doesn't mount the same way as one for a Civic, and guessing at it is how people end up drilling in the wrong place.
If you want to read the instructions for your car before you buy it, you can do that right now without asking us for anything. Browse the full manual library, or read on for why our front splitters are supplied undrilled.
How the manuals are put together
Four things, and each of them costs us time rather than saving it.
75 OF 80
75 of the 80 are written for one car
75 of our 80 manuals are written for a specific year, make, model and trim, so when your car's bumper geometry differs from the car parked next to it, the document differs too. The remaining five are the general manuals for each product family.
FREE FIRST
They are public before you buy
Every manual is a free PDF on our site, and we would rather you read the job and decide it isn't for you than buy the part and work that out afterwards, which matters more than usual on something that is final sale.
WHAT IS MISSING
They tell you what is not in the box
Splitter rods and brackets are not included, and the manual says so at the top rather than letting you find out halfway through the job with the car already on stands.
YOUR EXACT PART
They cover the part you actually ordered
Order a splitter with fins and you get a different manual from the same splitter without them, because you bolt the fins on before the panel goes anywhere near the bumper.
Four pages out of the eighty
These come straight out of the PDFs linked below, at the resolution they print at.
Download the general manual for any product family, right now:
Front splitter (PDF) · Front splitter with fins (PDF) · Side splitter (PDF) · Side splitter with fins (PDF) · Universal rear side fin (PDF)
Looking for your specific car? All 75 vehicle-specific manuals sit on the instruction manual page, sorted by product line and then by make. Find your SKU and download the exact document that ships with your part.
Why our front splitters ship without pre-drilled holes
The question we get more than any other.
A front splitter can't hang off the bumper cover. That cover is thin flexible plastic, so a rigid panel bolted to it flexes at speed, the fasteners work loose, and the plastic usually tears out around the holes. The splitter has to go into the bumper, undershroud and valence assembly instead, with that assembly bolted to the chassis so the weight ends up in the under-frame.
Most of that mounting happens in the undershroud, and the undershroud is the part of the front of the car we can least predict. Across the cars we build for, we see all of this:
Different shapes on the same model.
Trim levels and appearance packages change the undershroud, so two cars of the same year can turn up with different panels and the fasteners in different places.
Cars that never had one.
Some models never came with a full undertray from the factory, so there is less to mount into than the photos suggest.
Cars that had one and lost it.
Undershrouds are usually the first thing a speed bump or a curb destroys, and plenty of used cars are running without one or with a replacement that isn't quite the original shape.
Cars where somebody removed it on purpose.
Track cars, project cars, and anything that has had the bumper off more than a couple of times.
Cars with an aftermarket bumper or lip.
The whole mounting surface is then different from anything the factory ever built, and we cannot predict it.
So the panels ship solid. You test fit the splitter on your own car, mark where the structure actually is, and drill there. It takes longer than lining up somebody else's holes, but the holes end up in the right place for the car you own rather than for the one the drawing assumed.
If your undershroud has been removed or replaced, or the bumper is aftermarket, send us photos of the underside before you order and we will tell you what you are looking at.
All 118 front splitter applications carry the same requirements on their product page:
- Designed to fit the OEM undershroud
- The bumper, undershroud and valence must be mounted to the chassis to support the splitter's weight
- The assembled front splitter and bumper must be bolted to the under-frame
- Use brackets (not included) if your bumper is not bolted to the under-frame
- Mount as close to the front of the bumper as possible
- If the OEM undershroud has been removed, additional mounting may be required
- Removing splash guards is recommended for better fitment
- Splitter rods (not included) are recommended for high-speed use
What every manual covers
Six sections, on every one of the eighty.
What is in the box
So you can confirm the shipment is complete before you start.
Tools you need
For most parts: a drill, a screwdriver, a 1/4 inch wrench, a 10 mm wrench, and a properly rated jack with stands.
How to test fit
Before anything permanent happens.
Where to mount
And how to tell whether what you're drilling into will actually hold.
Fastener sequence
So the panel ends up straight instead of pulled to one side.
What to check afterwards
Including retorquing after the first few drives.
Common questions
These come in by email most weeks.
Do Street Aero parts come with instructions?
Yes. Every part ships with the installation guide for that application, and the same document downloads free from our manual library. You can read it before you order.
Why are there no pre-drilled holes in the front splitter?
Because a front splitter mounts into the undershroud and bumper structure, and that structure differs from car to car. Trim levels change it. Some cars never had a full undertray. Plenty of used cars are missing theirs or running a replacement. A pre-drilled hole would be correct for one configuration and permanently wrong for the rest. Leaving the panel solid means you drill into whatever your car actually has.
Can I install a front splitter if my undershroud is missing or damaged?
Often yes, but expect additional mounting work. Our splitters are designed around the OEM undershroud, so if yours has been removed or replaced you'll likely need brackets to get the load into the under-frame properly. Brackets are not included. Email us photos of your underside before ordering and we'll tell you what you're looking at.
Do I need splitter rods?
They're not included, and they're not a substitute for mounting the splitter to the under-frame correctly. They're recommended for high-speed use as additional support. If the car sees track time or sustained highway speed, add them. Do the primary mounting properly either way.
Do I have to remove my splash guards?
We recommend it on most applications because it gives a cleaner fit, but splash guard designs vary. Test fit with them in place first and see how it sits before removing anything.
Can I install this myself, or do I need a shop?
Plenty of owners do it at home with the tools listed above and an afternoon. Go to a shop if you aren't comfortable lifting the car, drilling, or judging whether a mounting point is solid. Read the manual for your part first and decide honestly.
My manual is not in the library. What now?
Use the general manual for that product family as a reference, then email info@streetaero.com with your SKU or order number and we'll send the specific document.
Before you start
Three things worth saying before you order.
- Installation involves drilling on front splitters, side splitters and most rear diffusers, which is why we don't describe any of our parts as bolt-on.
- Aero sits lower than the bodywork it mounts to, so you will be planning around steep driveways and parking stops afterwards, more so on a lowered car.
- Test fit everything before you drill anything. That is the step that separates a part which looks factory from one that looks like it was fought onto the car.
Ready to order? Browse front splitters, side splitters, rear diffusers or a complete full kit. Or read every manual first on the instruction manual page.