Would I need to go with large diamiter if I wanted to front mount with the stock turbo? I mean the inlet duct for the stock turbo is ~2" or a hair more. Would it not be the useless if I went with say 3.5" or 3"?

 

I can tell you from experiece that 2in intercooler piping is good enough for 200rwkw on a hi-flowed S4 turbo (stock housing w/T04 wheel)
if you go 3in, 3.5in for intercooler piping you will get worse 'lag/apparent boost response'. Possibly might give you a slightly less boost loss over the pipe, just depends how much your prepared to sacrifice for this small (possible) gain in HP.

ps, the stock compressor inlet is 2.25in IIRC, the outlet is 2in exactly.

 

3.5" is massive overkill. 2.25-2.5" is much more sensible.

 

I ran all 2" pipe, and while I have no dyno numbers, the car ran 12.5 in the 1/4.

 

Aaroncake, did u do a 1/4 before before you put your FMIC or did you have an FMIC right from the get go?

 

That is awesome! I think 2.5" might be ok for me then. But I am definately going with 3" once I buy my TO4

Santiago


Thanks guys.

 

The car always had an FMIC. See http://www.aaroncake.net/rx-7/naturbo.htm

 

It's actually 60mm, which is a little larger than 2.25".


-Ted

 

Opps sorry, my bad, I should've measured mine again before recalling my memory...

Just out of interest what are the sized for the stock IC inlet/outlet and the throttle body elbow?

 

Yeah but all of those are O.D. which means they are smaller I.D. IIRC the stock compressor inlet is rather thick. Maybe 1/8th of an inch? Ah who cares. :p

I will go out and measure it again.

 

Your right and it also tappers down to a much much small dia. like maybe even 50mm where the very front of the wheel starts.

 

Aaron Cake- Was your 2" piping 2" O.D. or I.D.?

 

Ummm.......... you DO realise that the difference is only around 1mm?

 

Some pipes can be as much as 1/8th of an inch thick. It sometimes makes a difference.

 

Umm.. im not too current with the(outdated ) imperial system... but isnt 1/8th of an inch like 5mm?!!
thats massive for the wall of a pipe....... especially for anywhere near the 2-3in range of pipe? My exhaust isn't even close to that!!

or have I got my maths *** about and its not actually 5mm?

 

http://www.globaljewelry.com/mm2inchconverter.htm


1/8th of an inch is 4mm. That is the standard for any 16 or 18 guage pipe I forget which one it is. But its the one that most exhaust shops sell here locally.

Santiago

 

Exhaust tube is not 4mm wall thickness! That's steam tube!

18 gauge is 1.2mm thick, which is much more realistic. Also, most pipes are sized by their OD, not ID.