Is 2.5" Intercooler piping too small???
 

I am currently going to a single turbo (S472) but is 2.5" intercooler piping too small for this application?

I would like to run 3" piping but the intercooler I would like to use only offers 2.5" inlet/outlet tubes.

So would I be better off using 3" pipes and reducing it to 2.5" at the intercooler or just use 2.5" all the way through and just reduce it right from the turbo outlet which is 3"?

Thanks for any and all input. Trying to figure this out before I place my order.

2.5" is probably a restriction for that turbo. I would switch intercoolers personally but if you don't want to do that, keep it 3" all the way to the intercooler.

thewird

After much thinking I think you are right. I would hate to choke that turbo with too small of a piping. I will have to choose another intercooler. Any sugestions?

Have BELL intercoolers make an intercooler to your specifications. People spend way too much with namebrand crap which often doesn't fully suit their application.

thewird

^ And bell is not a name brand?

No, they actually make the intercoolers, not resell someone elses core with ridiculous markup.

thewird

I know about them. They are a widely known brand. I actually have one of their cores on my car.

It was $400 just for the core. I have no idea how much the custom endtanks would cost. That why it may be cheaper to get something used

My 3.5"x11.0"x14.0" core with endtanks was $676. I like there endtanks, they flare the outlets and have nice curves leading up to them. Not a boxy setup. This is from a previous intercooler I had them make...

http://thewirdsdomain.com/rx7/parts/...28Large%29.jpg

thewird

The Bell intercooler looks like a quality unit. I'll have to look into it. Thanks for the info.

bell are very good..however they aren't cheap,but good things usually aren't

I have 3' piping with a 2.5 intercooler. Mine works fine.

That information is not helping anyone LOL

thewird

Yes it is. At least now he knows its a option and can be done.

That's obvious from the get go >_>. It could be done with 2" too, that's an option as well right?

thewird

That's obvious from the get go 0_o. It could be done with 1" too, that's an option as well right?

Pretty much, car would still run :D

thewird

Question for Wird. Shouldn't OP be fine retaining his IC Considering the IC would nullify the effects of charge air heated from the 3in. to 2.5in piping change? Also the 2.5 piping is too short to create any real issue? Idk I've been nerding out just wanted to see if off base or not.

You should run no smaller than the compressor discharge. If your turbo has a 2.5" outlet run no less than 2.5", if it is a 3" outlet run no less than 3".

Ideally you need to look at the IC end tanks separately as they each do things differently. On the compressor side it should be thought of as a diffuser both slowing down and spreading out the airflow evenly over the core. If you could gradually step up from your 3" discharge to 3.25" or 3.5" just before the tank and then have the tank "fan out" over the core it would work very well.

On the IC discharge side it needs to be viewed as a "nozzle" speeding up air velocity into the engine, this means a end tank that tapers inward to the outlet tubing which ideally would step down (ie cone off of the tank from the 3.25-3.5" to 2.5" this will help pick up the lost velocity and aid with reducing pressure drop. Nothing is more backwards than seeing a IC being fed with a 2.5" pipe and then has a outlet of 3" or more. Your airspeed has been reduced and needs to be regained. Let's not even get into it is also now more dense requiring less volume.

Bell cores are not expensive at all, they are all I use simply because they are a known quantity, that being the flow rate they give is conservative and at 10psi. This means I know I can size a core properly not just guess at it. Way too many IC cores are just oversized for no real benefit or gain.

~S~

Thanks for the clarification, I wanted to hear someone apply some fluid dynamics with the real world situations. so basically your saying, slow down coming in for better spread through core, and accelerate out. My track car runs 2 .75 to 3 then 3 back to 2.75 I didn't set it up this way, I built it on a budget and it just happend to work out like that.

Go with 4inch;)

ive got 3 inch with my single setup i wouldnt go smaller

2.5" works just fine with 450whp. I'd go with a 3" if your considering 550+

agreed.

A well known street registered 13b Rx3 over here made over 600whp and ran low nines with 2.5" intercooler piping.

got an s472 on mine with an ebay 12x3x24 intercooler and 3" inlet and outlet. It screems! I had 2.5" piping on my 66mm turbo setup but going from 3.5" at the turbo down to 2.5" piping is just a huge restriction. I do however have a hillarious looking 3.5 to 2.5" 90 degree coupler if you decide on going the 2.5" piping route.

https://www.rx7club.com/attachments/...small-mail-jpg