At what power level will a 2 1/4"- 2 3/8" internal diameter cold side piping be a restriction? I've seen cars with 3" go over 2000rwhp just curious how far mine can go. Also at what point does the exhaust piping become restrictive (the piping before the turbo). After the turbo is a 4" open downpipe. Just wanting to know how far I can go before I have to change. Thanks
Turbo piping--restrictive points?
- Thread starter ZACH'S97
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Ideally you should go 4" from the downpipe out to the tips. That isnt always possible for your budget or room and you should go with 3" in that case since it's the easiest to manage and most cost effective way.
As far as concrete data I'm sure someone will come in with a more numbers based reply but I'd say anything around 500hp-1000hp 3" is ok. From 1000+ I'd go with 4".
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I have an open 4" downpipe dumped in the fender. I have 2 1/4" cold side piping and either 2 1/4"- 2 1/2" hotside, merged into a 3" feed pipe to feed the turbo. How far will this get me? I've got oem manifolds that have some port work too. Piping size is very close to hellions stuff. Not concerned about the downpipe because 4" on a 76 is pretty big. Anyway, let me know. Thanks
youll lose some power and some spool time i'd image but it isnt the end of the world.
You are fine on the hot side, the biggest restriction is at the turbo anyways, on the cold side i would run 3'' or 3.5'' on a blow thru set-up, if you have a draw thru you'll be fine.
The size of the piping is not the only thing you should be worried about. The major problem is the bends and turns that the air and exhaust need to go through. The best system that will yeild the best power and the best response will be the one with the smoothest turns. Any angles will cause disturbances in airflow.
Here is a guy that I've dealt with that designed his own intercooler for DSMs with great results: http://dvdtfab.com/intercoolertestlab.pdf
I know it's a lot of technical jargon but his research is solid.
Here is a guy that I've dealt with that designed his own intercooler for DSMs with great results: http://dvdtfab.com/intercoolertestlab.pdf
I know it's a lot of technical jargon but his research is solid.
Thanks. Overall the transitions are fairly smooth. Especially in the cold side piping. I'm just trying to figure out where 2 1/2" OD piping on the coldside will start being a restriction. I think I'll max my 76 before I get there, but am going to a pt88 next fall or winter.
I ran 3in. coldside stuff when I made 827rwhp. The new setup will have 3 1/2in coldside piping..
The outlet of the PT88 uses the "H" cover ( 3"), so it would logically make sense to run 3" and not bottle neck it back down to 2.5". I would do 3" in the cooler from compressor outlet, then 3.5" from cooler outlet into throttle body, and run the MAF in blow through.
I talked to someone at Turbo People about this. I know you said yours is similar to a Hellion so this was the advice I got. He said don't worry about the cold side tubing as 2.5" will support a ton of power on a 4.6. He said spend the money no a GOOD intercooler(lots of better options than the one in the Hellion kit) and spend the rest on downpipe (4" or bigger).
The reason why people upgrade to bigger piping on the hellion kit is because they switch to blow through, with a bigger pipe the maf has more reading range due to the velocity of the air.
Nice link. :rockon:
Yes, but those that do change all the cold side are doing it the expensive way. Nothing wrong with that at all and the way I will be doing it. The inexpensive way is just putting a larger straight section in the fender and using reduction couplers to maintain the rest of the piping from the cooler to tbody.
The way I will do it is using a Vortech polished transition elbow at the tbody so that gets rid of the transition coupler from Hellion. Then use 3.5 inch piping for the section in the engine bay and when back in the fender I will use 3 inch pipe to the intercooler.
Mine is blow-thru and has larger piping for the section in the fender, the rest is all stock Hellion stuff.
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