Turbo or Supercharger poll

**EE1983** · 04-30-2006, 03:21 PM

Originally Posted by ericwilloughby

Before the turbo. We're talking about how much back pressure the turbo is making to drive a fairly bitchin' compressor.

Headers, cutouts if using a STS, what ever.
Cam is a no no because of overlap.

There is enough back pressure you don't even need a muffler.!!!

I just didnt see the point in measuring backpressure. In theory, a turbocharger is usually considered more efficient because it is using the wasted energy in the exhaust stream as a source of power. I always thought just using exhaust isnt actually draining power from the motor, but the supercharger clearly is.

**caseyWS6** · 04-30-2006, 10:08 PM

Originally Posted by WinSomeLoseNone

I gotta say turbo. I watched two identical irocs (350 tpi 5spd both 89) go at it, one turbo and one vortech supercharged and the vortech obviously pulled but once that turbo spun up it was over he blew the superchargers doors in. Ever since watching that i have always been a turbo man.

The problem was it was a Vortech my husband and brother had them they sucked, switched to Procharger the difference wasn't even comparible totally awesome now

**ericwilloughby** · 05-01-2006, 07:19 AM

Originally Posted by EE1983

I just didnt see the point in measuring backpressure. In theory, a turbocharger is usually considered more efficient because it is using the wasted energy in the exhaust stream as a source of power. I always thought just using exhaust isnt actually draining power from the motor, but the supercharger clearly is.

Of course a turbo is more efficient. But not free. And much less efficient in the rear. The question was:

Does anyone know? at 3,000 and 6,000 RPM:
How much HP is wasted driving a SC and
How much HP is lost due to back pressure and the inability to use exhaust mods on a turbo?

**Granatelli** · 05-01-2006, 09:44 AM

Originally Posted by ericwilloughby

Back pressure itself is easy to measure. Put a gauge on it. I think you would be surprised how high it is.
What would have to be intuitive is how much HP is lost due to that pressure. I.E. I've driven on a clogged cat, due to NOS on 93 LT1, and 35 was my max speed.
If anyone has measured it or can just guess.
Just guess.

Also, a turbo can't utilize headers, cam, and open Ex system.
Could these things make up for the belt drive loss in a SC. = or > turbo HP.

There is back pressure in all applications - Turbo, N/A and Blowers. That is why bigger exhaust helps all engines to a point and then it looses torque. Exhaust is like a balancing act

Turbo can benefit from Cams and certainly open exhaust. Turbos HATE restrictive exhaust systems so cut outs make a huge difference

**Granatelli** · 05-01-2006, 09:52 AM

Originally Posted by ericwilloughby

Back pressure itself is easy to measure. Put a gauge on it. I think you would be surprised how high it is.
What would have to be intuitive is how much HP is lost due to that pressure. I.E. I've driven on a clogged cat, due to NOS on 93 LT1, and 35 was my max speed.
If anyone has measured it or can just guess.
Just guess.

Also, a turbo can't utilize headers, cam, and open Ex system.
Could these things make up for the belt drive loss in a SC. = or > turbo HP.

There is back pressure in all applications - Turbo, N/A and Blowers. That is why bigger exhaust helps all engines to a point and then it looses torque. Exhaust is like a balancing act

Turbo can benefit from Cams and certainly open exhaust. Turbos HATE restrictive exhaust systems so cut outs make a huge difference

**Granatelli** · 05-01-2006, 10:47 AM

[QUOTE=ericwilloughby]Of course a turbo is more efficient. But not free. And much less efficient in the rear. The question was:

Originally Posted by ericwilloughby

Does anyone know? at 3,000 and 6,000 RPM:
How much HP is wasted driving a SC ?

About 35hp at cruise - this is AT CRIUSE if the question is 3k to 6K at Wide Open throttle then you're talk'n like 100hp to drive the blower

Originally Posted by ericwilloughby

How much HP is lost due to back pressure and the inability to use exhaust mods on a turbo?

You can use exhaust mods the other post is wrong. As for headers, naturally you don't normally use header with a turbo but the cut out is a big help even with the turbo. The "extra back pressure" caused by the turbo costs perhaps 40hp ay WOT. That is why a turbo can make a ton of power of low boost and a blower takes more.

As an Example: Starting with a 300hp engine on a dyno (assume the N/A car makes 300 to the tires)

N/A = 300 (this is our base)
Roots blower at 15psi = 480 to 500
Centrifugal blower at 15psi = 520 to 545
Centrifugal with intercooler at 15psi = 565 to 585
Turbo intercooled at 15psi =585 to 600 but with about 100 to 140 ft/lbs more torque then the centrifugal

**ericwilloughby** · 05-01-2006, 11:53 AM

Good numbers. If they are close then I was right. The "extra back pressure" caused by the turbo costs perhaps 40hp ay WOT.

If :
Turbo intercooled at 15psi =585 to 600
Centrifugal with intercooler at 15psi = 565 to 585
Then the turbo reduces output by almost as much as the blower because it only makes 15-20 more HP then the centifugal. If the blower is robbing 80 than the turbo is robing 50-60.

**ericwilloughby** · 05-01-2006, 11:55 AM

The other post is not wrong.
You can't use cut outs on a rear mount turbo.
Headers are "almost" useless. Same with cam.

Unless you have some dyno experience that says otherwise. I'd like to know.

**Granatelli** · 05-02-2006, 06:35 AM

Originally Posted by ericwilloughby

Good numbers. If they are close then I was right. The "extra back pressure" caused by the turbo costs perhaps 40hp ay WOT.

If :
Turbo intercooled at 15psi =585 to 600
Centrifugal with intercooler at 15psi = 565 to 585
Then the turbo reduces output by almost as much as the blower because it only makes 15-20 more HP then the centifugal. If the blower is robbing 80 than the turbo is robing 50-60.

The numbers are theoretical. and there is NO EXTRA back pressure caused by the turbo. If you were to install a pressure gauge at the collector on a supercharged car V. a turbo cat the pressure in the exhuast "should be" close to the same unless you had a crappy exh system

**ericwilloughby** · 05-02-2006, 12:55 PM

Of course there is extra back pressure. The scroll squeezes the exhaust down to about 1.6 inches or so. And you verified the amount of loss when you theorized the #'s for turbo vs. SC and there was not a 80 HP differance between the two.

**Granatelli** · 05-02-2006, 02:38 PM

Originally Posted by ericwilloughby

Of course there is extra back pressure. The scroll squeezes the exhaust down to about 1.6 inches or so. And you verified the amount of loss when you theorized the #'s for turbo vs. SC and there was not a 80 HP differance between the two.

So then if I understand you correctly, you chose to believe what you want to

Just to prove a point I just unscrewed the EGT out of the #7 exhaust port of my 2006 Vette. With an 8psi Procharger is has 16psi of back pressure at 6300rpm. So now I pulled the belt off and made a quick pull with no belts. It has 7.2 psi of pressure in the exhaust N/A. That sucks.

I then checked the back pressure in a 05 Mustang with a 12psi turbo and all 3inch single exhaust. At 6500 and 12psi it only has 18 psi in the exhaust. I then took the discharge tube of the intercooler and made a pass. Granted the car ran like Crap but it only has 4psi back pressure through the turbo exhaust but without the benefit of the turbo pressurizing the intake

What is the point? The turbo makes no more back pressure in the exhaust then the next system

**goldfingerfif** · 05-02-2006, 04:04 PM

I dunno if someone has said this but it takes about 5hp from the engine to make a turbo give it an additional 100hp. It takes about 30hp from the engine to give it 100hp.

Sorry I admit I am biased and I think a turbo is better in almost everyway. I just hate the hillbilly thought of just strap the thing to the engine.

**ericwilloughby** · 05-03-2006, 02:44 PM

Originally Posted by Granatelli

So then if I understand you correctly, you chose to believe what you want to

Just to prove a point I just unscrewed the EGT out of the #7 exhaust port of my 2006 Vette. With an 8psi Procharger is has 16psi of back pressure at 6300rpm. So now I pulled the belt off and made a quick pull with no belts. It has 7.2 psi of pressure in the exhaust N/A. That sucks.

I then checked the back pressure in a 05 Mustang with a 12psi turbo and all 3inch single exhaust. At 6500 and 12psi it only has 18 psi in the exhaust. I then took the discharge tube of the intercooler and made a pass. Granted the car ran like Crap but it only has 4psi back pressure through the turbo exhaust but without the benefit of the turbo pressurizing the intake

What is the point? The turbo makes no more back pressure in the exhaust then the next system

What are you taking about? You are making the numbers that prove I am right but you refuse to see it. I am very impressed that you actually took the time and work to measure the back pressure.

18psi is significant. I didn't know it would be that high.

Of course the turbo creates extra back pressure. It's a restriction in the exhaust that drives a compressor. WTF.

The SC does not impose back pressure on the exhaust. You arn't measuring back pressure caused by the driving of the SC. You are measuring the exhaust pressure created by making more HP. The running of more fuel and air into and out of the engine.

**Bigrus** · 05-03-2006, 09:22 PM

turbo

**grandkodiak** · 05-04-2006, 10:07 AM

are headers and hiflow cats useless to a turno setup? i was always planning a blower so i'm new to the turbo thang... but i have headers and hiflows awaiting install... if i sell them off i'll be that much closer to turbo if i go that route and wont gain anything... i'll be saving nearly a grand in installation if i can manage to run without them...

**01SCSS** · 05-05-2006, 12:45 PM

I'm runnin a Procharger and I still say TURBO!

**vxchev8** · 05-06-2006, 05:31 AM

I voted turbo but wouldn't knock back a cheap s/charger kit

Snake Eater · 05-08-2006, 12:28 PM

turbo

**ericwilloughby** · 05-08-2006, 03:39 PM

Originally Posted by grandkodiak

are headers and hiflow cats useless to a turno setup? i was always planning a blower so i'm new to the turbo thang... but i have headers and hiflows awaiting install... if i sell them off i'll be that much closer to turbo if i go that route and wont gain anything... i'll be saving nearly a grand in installation if i can manage to run without them...

I am not the expert and just cant bring myself to put down the $5,000 for a SC or turbo. I'd rather buy a new 05 GTO. But you would get less, maybe much less, of a gain moding the exhaust of a turbo car. Headers are supposed to create a suction on the valve. Scavenging. Thats why there is a separate tube for each EX port. It would be very hard to get that done with all the tubes emptying into a 1.6" turbo scroll. And a turbine blade blocking the path.

Do any of the factory turbo cars have headers on them??????

I have asked before. Will an SC engine with headers and exhaust and maybe a cam make the same power as the same engine with a turbo?? Same boost and intercooler of course?

Granatelli, do you know?