ID, OD, getting a headache thinking about this

[Sariandan]

Okay.... I'm having issues thinking about sizes. As far as I'm concerned, <---> is 12 inches. But, I don't think that's going to work for my problem.

So, I recently received my SPD downpipe with 3" outlet. I didn't think about it until after it had shipped, but my 3" cat-back mated up to the stock downpipe. The stock downpipe is 2.5", correct?

Okay, so where I'm getting a headache is thinking about the internal diameter vs outside diameter of various exhaust components. The front end of the cat-back exhaust slipped into the factory downpipe. I'm thinking that for a connection to be made, I'm going to need a connector that is 3" internal diameter on the downpipe side (so that the downpipe will slip into it) and 2.5" outside diameter on the cat-back side (so that the exhaust slips into it, like it did the factory downpipe).

Does this sound right?

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[P. A. Schilke]

Okay.... I'm having issues thinking about sizes. As far as I'm concerned, <---> is 12 inches. But, I don't think that's going to work for my problem.

So, I recently received my SPD downpipe with 3" outlet. I didn't think about it until after it had shipped, but my 3" cat-back mated up to the stock downpipe. The stock downpipe is 2.5", correct?

Okay, so where I'm getting a headache is thinking about the internal diameter vs outside diameter of various exhaust components. The front end of the cat-back exhaust slipped into the factory downpipe. I'm thinking that for a connection to be made, I'm going to need a connector that is 3" internal diameter on the downpipe side (so that the downpipe will slip into it) and 2.5" outside diameter on the cat-back side (so that the exhaust slips into it, like it did the factory downpipe).

Does this sound right?

Hi Kevin,

Yep for this scenario, but depends on your system cat back fitment to a 3 inch down pipe...I thought 3" was internal on aftermarket down pipes so you need an adapter to accommodate pipe wall thickness as well...but I will let those that have done this address this.

The key as I see it is to measure Od and Id of both systems and down pipes...Then this becomes clear as I have been through this time and time again at Ford trying to tune a vehicle to an exhaust system... Prototype systems from Arvin and cats from another supplier and manifold attachments from Bendix....Yikes...

Best,
Phil

 

[Sariandan]

Hi Kevin,

Yep for this scenario, but depends on your system cat back fitment to a 3 inch down pipe...I thought 3" was internal on aftermarket down pipes so you need an adapter to accommodate pipe wall thickness as well...but I will let those that have done this address this.

The key as I see it is to measure Od and Id of both systems and down pipes...Then this becomes clear as I have been through this time and time again at Ford trying to tune a vehicle to an exhaust system... Prototype systems from Arvin and cats from another supplier and manifold attachments from Bendix....Yikes...

Best,
Phil

Thanks, Phil! I should have just paid attention and thought things through before submitting the order, but you know how that money is always trying to just jump out of the wallet.

I have measured the downpipe and it appears to be 3" outside diameter. I have ordered a few different adapters to try. I also sent an email off to SPD to see what they recommend. I'm hoping someone here has done this, although most people here seem smart enough to have slowed down and ordered the right outlet size.

 

[D Fresh]

From Stage 3 on their SPD downpipe page.

This downpipe comes with two exit adaptors, one connects the Ranger's factory 2.5" exhaust connection and another 3" connection attaches to the catback exhaust.

If your catback was designed to connect to the factory downpipe you'll probably have to use the first one mentioned. If your catback is designed to mount to factory downpipe OR an aftermarket 3" downpipe the second one mentioned should do it. What catback do you have?

 

[Sariandan]

The downpipe does not come with an adapter if you choose the 3 inch exit. I have the MBRP single exit cat back, 3 inch. It connected to the factory downpipe without an adapter.

 

[D Fresh]

The downpipe does not come with an adapter if you choose the 3 inch exit. I have the MBRP single exit cat back, 3 inch. It connected to the factory downpipe without an adapter.

Okay, so you got the full stainless one, right?

Did you buy from Stage 3?

https://www.stage3motorsports.com/d...-3l-ecoboost-spd-3in-ss-catted-downpipes.html

That one?

Their website says...

. This downpipe comes with a step-down connector that connects to the factory 2.5" cat-back system. A 3" adapter is available at additional cost from our drop-down menu above.

And the drop down indicates you are paying $20 extra for the "additional adaptor."

"Add" says to me you paid $20 to get BOTH adaptors.

I'd contact Stage3 if indeed you purchased from them.

 

[Sariandan]

I ordered from 5star. The info on the websites is apparently old from other things I’ve read. I’ve got an email in to SPD, as well.

In any case, do you have any insights as to the measurements I gave? I believe I’m thinking about it correctly, after having some sleep. I’ll let y’all know how it turns out.

 

[Fawnbuster]

You can also go to a local exhaust shop and for a few bucks have them use a die and adjust your parts (off the truck) or make a quick adapter if you end up needing one.

 

[D Fresh]

I ordered from 5star. The info on the websites is apparently old from other things I’ve read. I’ve got an email in to SPD, as well.

In any case, do you have any insights as to the measurements I gave? I believe I’m thinking about it correctly, after having some sleep. I’ll let y’all know how it turns out.

In my experience ID is generally what's listed on exhaust components, but I cannot say.

The Ranger is an odd duck when it comes to exhausts. Every thing I can find for it goes together with clamps like a cheap J.C. Whitney kit. I'm used to real deal flanges on a $1000 TBE, myself. Perhaps that's a result of Ford's original design.


That being said, old info or not, the website states clearly that you get both if you paid the $20. IMHO, Stage3 owes you the adaptor you need.

Howabout it @Stage3Motorsports ?

What do you say?

Disregard. I'm stupid.

 

[Sariandan]

@Stage3Motorsports ?

What do you say?

I didn’t order from Stage3. I’m not worried about the cost of a $10-20 adapter piece. Just making sure I’m thinking about the connection properly. I have ordered a few adapters in different combinations of 3 and 2 1/2 inch ID and OD. I’ll let y’all know which one works when I get around to installing the downpipe and return the rest.

I appreciate your input above.

 

[D Fresh]

I didn’t order from Stage3. I’m not worried about the cost of a $10-20 adapter piece. Just making sure I’m thinking about the connection properly. I have ordered a few adapters in different combinations of 3 and 2 1/2 inch ID and OD. I’ll let y’all know which one works when I get around to installing the downpipe and return the rest.

I appreciate your input above.

I'm sorry, I must've seen the number and my brain filled in the rest?

In that case, if you need further info I'd contact SPD direct. Chances of you getting a reply from reaching out to 5Star are slim to none.

Good luck, watching to see what you find out.

 

[Sariandan]

I'm sorry, I must've seen the number and my brain filled in the rest?

In that case, if you need further info I'd contact SPD direct. Chances of you getting a reply from reaching out to 5Star are slim to none.

Good luck, watching to see what you find out.

SPD just returned my email from last night. They sell the adapter here. No real information on the product page, but if one of the ones I’ve already got on the way doesn’t do it, I know I can order that one.

 

[OFC Ranger]

You can also go to a local exhaust shop and for a few bucks have them use a die and adjust your parts (off the truck) or make a quick adapter if you end up needing one.

Yup when I ordered my Flowmaster 40 muffler I accidently ordered with the inlet/outlet half inch smaller. My local exhaust guy through the muffler on his machine and in 2 seconds the die stretched the tips open that extra half inch.

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