Sarg

iTrader: (6)

Here is where we got the idea to change. They use 2" primary thick wall tubing.

http://www.full-race.com/store/turbo...-manifold.html

Edit: inside diameter was around 1.78", outside was 2.0"

Phil99vette

iTrader: (11)

AFAIK, Full race uses 1.25 and 1.5 schedule 40 pipe for their manfolds. The 1.25 schedule 40 evo manifolds are about 1.375" ID while the 1.5" schedule 40s are 1.61" ID. I dont know of anyone using schedule 10-40 pipe with a SBC/BBC/LS. Everyone I know uses 18/16g tubing which has 1/2 the wall thickness if that. A 1.75" 16g has a larger ID than a 1.5 schedule 40.

Sarg

iTrader: (6)

It has been several years, but I could have sworn he used 2" stuff which was around 1.78 inside diameter and went to twin 2" ID pipes leading into a T4 turbo. We bought whatever it was he recommended but I could have sworn it was 1.78 ID

Phil99vette

iTrader: (11)

So did you ever build and test multiple combos or just buy what someone else recommended? The only problem with using pipe sized elbows is they only offer a couple useable sizes. I am somewhat reverse engineering street combos from proven race combos. When you take what you said and apply it to race combos, the tubes just doesn't make logical sense.

Better yet, what do 1200-1300hp imports use for tube sizes?

Sarg

iTrader: (6)

I have never built a 1200 hp import. We only tested the two combos. We were surprised to see the increase in spool up with the larger pipe size. We initially built it with the smaller size to try to promote more exhaust velocity but found that the subarus with their long exhaust tract seemed to like larger exhaust for whatever reason. This was a 400 awhp street car.

Crystalss

I figured i would give this thread a bump...so I will ask some questions.

How much would 2" crossover support? around 1000?

Obviously my power will be much less than that so I am thinking about 2" crossover for my street LT1...hell I am actually kicking around the idea of 1.5" header primaries. On my setup I will have to merge the two 2" pipes into a single 2.5" pipe into a t4 .96 ar t70 MasterPower turbo. Or should my merge be a single 2.25" pipe? The merge will be about a foot long with a 90.
two 2" pipes = 6.28 cross section
one 2.25 = 4" cross section
one 2.5 = 4.9 cross section

Looks like 2.5 is the better merge size? Comments?

turbocamaro125

iTrader: (3)

Phil...what will 2" support? 1k-1.2khp?

Phil99vette

iTrader: (11)

Considering 2.5" will support 2400hp
2.25" will support 1800hp
2" would support 1000hp.

2000camaroSS2000

all kinds of great info in forced induction today, been on this forum for awhile. subd to 3 more threads today for a total of about 14 in 3 or 4 years

Phil99vette

iTrader: (11)

One day I am going to build a 1500hp x275 motor and I am sure it will make people scratch their heads on some things...

turbocamaro125

iTrader: (3)

What combo would you build Phil?...I would like to know!

RacerXLs1

iTrader: (14)

Me too lol

MattKatz

iTrader: (5)

I read this....Now you have me thinking.

Phil99vette

iTrader: (11)

Dont take my advise, get maximum boost by corky bell and do some research.

Seems like a majority of v8 owners put retarded size pipes on their setups without ever testing or researching.

Some of my import friends make headers out of 1.25" schedule 20 pipes for a 400-500hp build.

MattKatz

iTrader: (5)

I dont have time or patience to read stuff like that....Never have. I think all books should be condensed to the Nitty Gritty important cliffs....Thats all I want/Need.

Phil99vette

iTrader: (11)

In that case a 3" crossover would work perfect.

MattKatz

iTrader: (5)

Thanks Smart one...lol.

67Firebird455

iTrader: (27)

Just run a 2.5" bro. If it's a dedicated race truck, and you're making that much power, then run the 2.5". Myself... I'm running 2.25" to my T6 but will be in the 750-1000whp range where I have absolutely zero reason to use 2.5".

RB440MIKE

Hi Phil,
Oddly enough, I was going to finish my 2.5 cross over for my 5.3 single turbo. It is about 1/2 way done, but I'd rather get it right now than do it all over again to optomize it later. I am using an f-car manifold on the left and a log manifold on the right. The manifold has a piece of schedule 10 2 inch stainless which has an ID around 2.25. The log on the right is sc 10 2.5 inch which matches the T4 flange nicely when ovalled with a vice. That all being said, I grabbed my copy of Maximum Boost and was not able to find the math to determine the correct cross over size. There was a mention of mach numbers and flow in the intercooler section. I would like to understand the math behind this. I would greatly appreciate any help so that I can size this cross ove correctly.


Thanks
Mike

Phil99vette

iTrader: (11)

You using 1 or 2 turbos? Any pics