Power limit of 1.625" turbo headers

[JBrady]

Guess how much power you can make through 1.625" header pipes on a turbo V8?

The following link is for the following specification engine:

Ford Windsor 351 based engine bored and stroked to 427cid / 7 liters.
Twin Precision turbos' 78GTS'S .96 turbine housings
TFS-R heads with 2.125 intake 1.6 exhaust valves flows 360/[email protected]
Cam .050 242/248 .670 lift 114*
TFS-R Shorty headers flipped 1-5/8"
3-1/2" off turbo's to 4" to the rear axle

http://speedtalk.com/forum/viewtopic.php?t=9213&start=15

 

[JBrady]

Considerations.

This is a drag racing Mustang.

It has an automatic transmission, high stall converter and racing slicks which would definitely cause a relatively large drivetrain power loss.

That said, this thing still puts down 1382rwhp which is AT LEAST 1500hp at the engine (probably significantly more).

So, these little 1 5/8 header tubes are supporting more or less 200hp EACH tube!

This run was at 30lbs boost and only had 31lbs of backpressure which is very low.

 

[JustenGT8]

No surprises there J....i try and use 1.25inch ID pipe for a 500cc cylinder. Down to 1 inch for smaller cc. Keep the velocity up and the heat in...all good for a turbo. GT8 runs 1.25 inch ID thick wall pipe and i wouldn't think of going larger until past 1000hp.

Pipes always flow alot more than people think. Just look at intake restrictors for race/rally cars. Pretty standard to make 300hp thru a single 36mm restrictor

 

[JBrady]

No surprises there J....i try and use 1.25inch ID pipe for a 500cc cylinder. Down to 1 inch for smaller cc. Keep the velocity up and the heat in...all good for a turbo. GT8 runs 1.25 inch ID thick wall pipe and i wouldn't think of going larger until past 1000hp.

Pipes always flow alot more than people think. Just look at intake restrictors for race/rally cars. Pretty standard to make 300hp thru a single 36mm restrictor

Great stuff! Do you have any pictures of your manifolds?

 

[JustenGT8]

Yup i have a few pics, send me your email.

These are just from my own or mate's projs, i don't do this for a living

 

[XR8tt]

I'm runing 1 1/4 steam pipes into 2" collector before turbo, on a 337 turbo Windsor
Over 700 h.p...With two Precision T3/4 turbo's...

 

[Sabre_Logos]

Pipes always flow alot more than people think......

I figured this out when I built my turbo system. I'm running all 8 cylinders into a 2 inch OD pipe that goes for 8 feet before it feeds the turbo.

The car pulls hard all the way to 6900 rpm. Of course, I'm running a measly 6 psi for the moment so there might be some issues as I raise the boost. But the car is putting out over 420 hp at this boost level so, all in all, I'm glad I went with the smaller pipe size.

 

[ed_ma61]

small dia turbo headers are greatly overlooked by most (god knows why, usual story i guess)

 

[XR8tt]

Keep in mind this engine is 4.0 Ltr 8 cylinder ... You can easy get 450rwkw + from a healthy 4 ltr 6with 1 1/4pipes. Let theexhaust gasses expand in turbine housing. Better low rpm spool... The mustangs use 1 5/8 header, they reverse the std [restrictive] headers and 500 - 1000 h.p with decent block...It's still pulses an under pressure.. Just need to stop thinking what works n/a....
On these 4 valve heads, when I make mine I'll make a collector type reducer from flange to primary to prevent reversion. don't want any turbulence there. plus having flange slightly larger helps prevent reversion, even if further down it [primary] gets a little smaller...
These are still street engines. If they where designed to run constant 6000 to 9000 rpm constantly ! Then that's another story...
The turbo F1 engines had around 35mm pipes for a 1500cc engine, but hardly a street engine...

 

[XR8tt]

Edit ....The turbo F1 engines had around "55mm" pipes for a 1500cc engine, but hardly a street engine.. Over 2"....

 

[stevechumo]

I don't use really big pipes for my manifold. I keep the driver side stock header, with cross runner of 1.75" merge to the fabricated 1.75" passenger header. These 2 merge into a single 2.5" pipe and run to the turbo. I have instant boost without any lag. I have 2 advanges. First is the fabricated small passenger manifold allow me to install it easily. Second is the the exhaust pressure is quicker eliminating lag. Here's the link: http://lextreme.com/forums/showthread.php?t=7031&page=6