Zombie

iTrader: (2)

Going dual 2" will flow more, but I have no idea how much it will help.

TracyRR

iTrader: (8)

Hey phil, do you think the dual 2" charge pipes that i'm about to do are about the right size to use? Any other opinions before i start running pipe? thanks guys

Phil99vette

iTrader: (11)

What size do you have now, can you use 1 tube or does it have to be 2? I'll put it in the calculator and see what she comes up with tomorrow.

TracyRR

iTrader: (8)

i currently have dual 1.75" charge pipes and was going to change over to dual 2"... because of packaging, i have to go with dual charge pipes instead of one larger pipe. Thanks!

Louis at GSS

iTrader: (1)

Holy small charge pipe batman!

Whats it make for power? Great work BTW, backpressure is something so often overlooked.

98Z28CobraKiller

iTrader: (17)

It will make more power with the "200 shot" but not as much as if the restriction were not there. Also the "200" in a "200 shot" is a reference to additional flywheel or RW HP. Some people simply correlate it to an advertised jet combo from a nitrous company. So your 200 shot may only give you 50-100 hp in your choked system where as it could make 400 on an unrestricted system depending on the boost level.

HydroStream6

iTrader: (16)

But what I'm getting at is, say you have an infinitely large waste gate. It cannot help for turbine back pressure as that would only decrease the amount of boost created (drive pressure and all that). But could it help with the overall "restrictiveness" of the exhaust system, giving the exhaust spent by the added nitrous a place to go?

TracyRR

iTrader: (8)

thanks louis, on 14 pounds it made a little under 700rwhp with high backpressure.... It actually made less power when i cranked the boost up. Now with the backpressure in check, it pulls much harder with more boost! My guesstimate would be 800+ rwhp at 18 - 20 pounds. Think i read somewhere that a restrictive charge side can increase backpressure on the hot side....? Is that correct? Thanks

BLKHAWK1

iTrader: (30)

I believe it would, anything that slows down the turbine speed can cause back pressure issues, I had a car with an air filter that wasn't sized correctly cause back pressure issues.

TracyRR

iTrader: (8)

Thanks

The precision 6262's have a 2.5" charge outlet but my gut is telling me that is too large unless i hear different. What do other twin guys run? Front or rear mount... just curious. Thanks

Phil99vette

iTrader: (11)

Ok on the charge pipe,
Dual pipes:
1.75" = 800fps
2.00" = 607fps
2.25" = 480fps
2.50" = 345fps

most of the setups are 500 to 625, 2" is money.

TracyRR

iTrader: (8)

You are the man phil!! question, i'm guesssing fps is speed? If so, my current charge side is too fast and causes what issue? I'm guessing it becomes a restriction. Thanks so much phil!

Phil99vette

iTrader: (11)

yeah, I take it as a way to generalize tube size. This is just stuff from a book, nothing I came up with.

JAX04

iTrader: (17)

Phil does it say at what pressure those numbers are?

Phil99vette

iTrader: (11)

I think they were...
19# of boost
.90 VE
.55 BSFC
7000rpms

TracyRR

iTrader: (8)

phil, in your fps post, at 800fps, is it a restriction or ?... Thanks

JAX04

iTrader: (17)

interesting, thank you

slow67

iTrader: (2)

Boost shouldn't matter, it should always be the same speed at .9 VE an 7000 rpms.

98Z28CobraKiller

iTrader: (17)

No. Exhaust gas is exhaust gas. Doesn't matter how you make it. The only way a larger wastegate will help anything is if your current WG is hanging wide open and you are over boosting and overpressure in your exhaust.

For exaggeration's sake, Let's say you have a tiny turbo (35mm T3 tiny) and you are feeding it with a big block v8. Now you have a little 38mm gate on the hotside. It would probably be at full boost at idle even with no spring in the gate and it hanging wide open. Now, you could put your "inifinity" gate on there and it would bypass all your exaust pressure out of it or just enough to keep the turbo spooled all the way up and the rest would go out of it. Not sure if that paints a clearer picture.

Phil99vette

iTrader: (11)

Power = airflow, as power goes up, airflow goes up. So your motor will move the same amount of air at 14# of boost and 700hp as 28# of boost and 1400hp??