yenkomike

iTrader: (2)

yes the piping is 2 1/4 single merge. the first few I built I used 2 1/2 pipe and they have been working great. my nova has a 2 1/2 and has gone 9.90 on 14 psi boost and seems to work well. the 2 1/4 is an effert to gain a little lowend spoolup. and as of yet I don't see any issue once in boost.

one of the hot sides I built is on my buddys Camaro with 2 1/2 to a single 2 1/2 looks exactly like the truck setup and has ran 9.40s on a 5.3 at 3550 raceweight with a on3 78/75 turbo @ 20 psi boost. I'm not seeing the big restriction at that power level yet. and i'll tell you the truck 2 1/4 setup pulls very good up stairs we have ran it to 7000 rpm on the ls2 370" engine and ljms stage 2 and it keeps pulling up there. thanks.

yenkomike

iTrader: (2)

here is the 2 1/2 one that runs 9.40s stock 05 5.3 with triple 12 cam and stock 706 heads on3 78/75 3200converter 400th and 3.73 gear. best 1/8 mile 6.05 @114 so far.

1CAMWNDR

iTrader: (21)

The 5.3s with smaller turbos might manage to work.....does not mean it is right.

A 370 feeding a bigger turbine needs more volume to spin the turbine while the car is at the starting line......not a merge pipe the same size as the primaries. If you want 2.125" or 2.25" then they need to stay divided all the way to the turbine wheel.

Forcefed86

iTrader: (4)

I’m not sure that’s a fact. Do you know the scroll exit diameter of a T4 1.25 housing? If it’s collectively smaller than a 2.25” pipe than the pipe isn’t a bottle neck. The 1.32 T6 is about 1.5” per scroll I’m told. I’m sure the T4 is significantly smaller, but I don’t know exactly. Stuff some clay in that sucker and find out for us!

Also the smaller pipes increased velocity will have a greater impact spool speed than additional volume. Question is if the piping is small enough to be a choke point at his 370s current power level. Which I doubt.

yenkomike

iTrader: (2)

the 2.5 pipe is very close to the inside diameter of the t4 flange . meening if you hammer a round 2.5 pipe square it is not to far off of the t4 flange size. the 2.1/4 is a little bit smaller but still larger than if you look at the inside of the turbine housing it necks way down before getting to the wheel itself.

my idea with single 2 .5 or 2.25 pipe is to gain velocity entering the turbo. I have seen no evidence showing the pipe is to small. in a week or so we will do some track testing and I will let you know how it works. I know the 2.5 single pipe works great . thanks.

C5_Pete

iTrader: (8)

In for data.

Good luck!!

1CAMWNDR

iTrader: (21)

Interesting........

93camaro_zzz

iTrader: (13)

I would be very interested if you changed that single 2.25" pipe, and reported back with results. That would solve the question of the pipe too small right there.

yenkomike

iTrader: (2)

we might but not until we get some solid track runs in to get a base et/mph with the 2 1/4 pipe.

69-chvl

iTrader: (11)

Good move!!

LilJohn

We back to backed a 2.5 merged to 3 with a fully divided 2.25 on a car that had datalogging capability.

the motor was 500 RPM quicker to get to 105 kpa, 5 psi , 10 psi.

The hotside was the only change.

93camaro_zzz

iTrader: (13)

500rpm is huge.

coltboostin

Exactly what the ferk I was looking for.

Thank you sir! Not sure how hard that set up was pushed but did you see any differences up top?

newschool72

iTrader: (12)

John, where do you put the waste gate on the 2 1/4" thats run all the way to the divided base ? Just 90* off the split, right at the turbo mount ?

Nitroused383

iTrader: (10)

500 rpm is huge, something I may need to try that in the future. But for now I'm going to install my PTC and see what happens.


Here is how mine is setup, single JGS 60mm works awesome.

newschool72

iTrader: (12)

Oh ok. That looks like it would work really well. Im considering doing 2 1/4" all the way on mine as well. If I could come in 500 rpms early it should solve my converter/boost issue.