I8UR4RD

iTrader: (16)

Very Interesting article.


http://www.gmhightechperformance.com...tegate_debate/

SPRAYED 01

iTrader: (22)

Its really not apples to apples when he puts a smaller pulley on at the same time.

35thsscamaro02

Older issue of gmhtp but A good one. Basically what I've done to my car. Except I pulleyed all the way down and have an electric boost controller on it. It makes for a fun ride. :-)

TrickrTreat

iTrader: (3)

Thats the whole point. To run the smaller pulley. If you did the test without a pulley change there'd be no difference. w or w/o the wastegate.

A centrifugal S/C requires the sizing of the pulley to determine its desired boost pressure.

Using the Wastegate, it allows you to run a smaller pulley that in normal conditions would result in a boost pressure that is Higher than desired.

You will see higher pressures early and peak desired boost earlier at a lower rpm and then bleed off the remaining amount of boost that is being continually created all the way through the rpm range.

It also carries dangers , like Impeller rpm redline. So theres definitely a fine line.

Detoxx03

iTrader: (14)

Some people do this with a restrictor plate but this gives the ability to control it with a boost controller.

Firehawk441

iTrader: (41)

What waste gate are you using?
What spring are you using?
Where did you mount the waste gate?

35thsscamaro02

It was a cheap eBay 44mm with like a 10lb spring in it I think.

Firehawk441

iTrader: (41)

Thanks.
How much total boost are you making with the 10# spring?

35thsscamaro02

I adjusted the spring pressure so it makes 11psi at peak. It carries 10lb from 4000rpm up pretty much. With the boost controller I can with a flip of a switch it will make 15lbs. I don't have any updated dyno numbers but it makes boost quick. Went from 4.25 pulley to 3.4

Firehawk441

iTrader: (41)

Thanks. That's what I've been trying to determine. What spring will work with 15lbs. total boost

ss2000silverbullet

iTrader: (12)

Or, use a boost limiting valve...
http://www.928motorsports.com/parts/...mitervalve.php

Firehawk441

iTrader: (41)

Nice.

MUFFINMAN89

I agree.

Staleyp

iTrader: (4)

Do you think that would bleed off enough boost?

allout06

iTrader: (11)

its only beneficial if your blower is bigger than what your motor can handle. i wanted to do this last year when i had the blower..

ss2000silverbullet

iTrader: (12)

Absolutely. All those ports in it will exceed the volumetric release of an average 44mm wastegate, plus, having the ball valve as the leading actuator is a BIG plus.
Since it's adjustable over such a long range, the spring must have little to do with the release compared to the ball valve - which I would think will make it much more reliable than a wastegate.

The Alchemist

iTrader: (19)

Personally, I don't get it. One of the best benefits that a centri-blower gives is that it continues to make more boost as the rpms rise, so it helps to make more horsepower. The article says that by putting in the wastegate, it helps to save the motor, but the most stressful rpm for a motor is at torque peak, 4400-5000 rpm, so bleeding off boost above that isn't helping out the motor, it's just limiting your overall power.

How many threads do we see on here that people complain about how their power peaks at 5200-??? rpm then falls off after that. People swap valve springs, plugs, wires, coils trying to chase down why their power drops off, but here we are going to do it on purpose? I don't get it.

What's better, 650rwhp/600rwtq or 600rwhp/600rwtq because you dump the extra boost above 5500rpm? To me having a motor that continues to pull hard past peak torque feels better than one that falls on it's face.

Just my opinion. I'm sure some people like it, but to me, adding a wastegate just adds another complication to the mix.

allout06

iTrader: (11)

your not going to make less power. look at it this way..

you have a stock shortblock and a D1 will make more power than your stock 347 can handle. say it made 550rwhp at 8psi. that means in mid rpm your making more along the lines of 4psi. if u add a wastegate, you can pulley the D1 down where it would normally make 15+psi on that motor, but have the wastegate open at 8psi. itll hold 8psi to redline. your still going to make that 550rwhp, but your under the curver power will increase because the blower is pulleyd down bringing the boost on much faster in the mid rpm range. make sense?

Taubr Unit

iTrader: (32)

Your basically making the blower act like a turbo and getting more boost at lower rpm's. I'd say skip the belt issues and headaches and just put a turbo on it.

TNTramair

iTrader: (15)

no more belt issues with the Aster Bracket....and Turbos have their own set of issues as well...they arent exactly maint free.