Black LS1 T/A

I've found a way to vary my boost between 7-8 lbs. and 9.5-10 lbs. of boost any time I like (without changing pulleys).

Anyone care to speculate how I do it. <img src="gr_stretch.gif" border="0">

If there's interest, I'll post the technique and you guys can beat me up on what's wrong with it. <img src="gr_grin.gif" border="0"> But it WORKS!

Nickn20

Vacuum leak? please enlighten us, great one <img src="graemlins/gr_hail.gif" border="0" alt="[hail]" /> <img src="graemlins/gr_hail.gif" border="0" alt="[hail]" /> <img src="graemlins/gr_hail.gif" border="0" alt="[hail]" /> <img src="gr_grin.gif" border="0"> just messing hehe

Z00

I'm curious about this too. The only way I know of is to change your shift points.

Black LS1 T/A

Hah!
Nope... not a vacuum leak. LOL! <img src="gr_grin.gif" border="0">

Please humor me for replies... I promise to tell you what I've done after this great crowd of techies proffer their own ideas, schemes and plans...

It's very simple and takes ony a few minutes to set up. But it really works. I hope we can have fun with this... and it's something Vortechs and ATI's have in common, so I'm assuming it will work for Vortechs.

Black LS1 T/A

Those are both good answers! It's as simple and hokey as Nickn20's suggestion. But you don't have to sacrifice RPMs to do it. (Although, since more boost, in my experience, can make RPMs come on quicker, which induces a tendency for RPMs to sometimes peak a bit higher.)

I'm glad there's interest. It is VERY simple! But again.. it works!

You don't have to change shift points nor do you induce or tolerate some type of vacuum leak. Someone will guess this... they just probably haven't realized you can make the boost consistent and predictable, therfore useable.

I'll want to debate you guys opinion of what the long-term impact would be. I think the cost would be VERY small.. I'm talking a few dollars. You may have to spend an hour or so maintenance for this inexpensive item every six months to a year or so, but maybe not. However, you can change your boost by a couple pounds, up or down, ANYTIME you want, with minimal tools and little to no mechanical expertise.

Imagine... run 5 or 6 PSI on the street driving around town or to work, but having 'mad' power of a 5 or 6 PSI SC when you want it, all on 92 or 93 octane. BUT, when you go to the track, or expect a grudge match on the street, buy some 100+ gas, or add toluene (or whatever it is you do for high boost application), spend only five minutes under the hood, and change your car from a 12 second machine to 7 or 8 lb. mid-11's machine! <img src="gr_grin.gif" border="0">

I changed mine from a mid 11's to a very low 11/high 10's machine by changing my boost back and forth between 7-8 PSI and 9.5 to 10 PSI. I've done this for a few weeks and reserved judgement about it's effectiveness until nearly a month elapsed... now I want to share it with my fellow LS1'ers to try, whether it be something you think is too hokey to try as a legitimate variable boost tool or a stupid gimmick.

But, IT WORKS!

Jason at GWP... you're not allowed to tell... I hinted to you this weekend what I had done. <img src="gr_grin.gif" border="0">

EuG

Adjustable blow off valve...
<img src="graemlins/corvette.gif" border="0" alt="[Corvette]" />

RacerX

a Waste Gate?

Black LS1 T/A

There is NO initial investment in this technique. You will be using existing hardware... well, not REALLY HARDware. <img src="gr_images/icons/wink.gif" border="0">

XLR8NSS

iTrader: (4)

Dag gonnit Mike. What is it already? <img src="gr_stretch.gif" border="0">

I've got an idea but it doesn't fit your hints very good. Do you somehow limit how far the bypass valve can close? Maybe with a piece of rubber hose on the arm. <img src="gr_stretch.gif" border="0">

Alright now tell us. <img src="gr_grin.gif" border="0">

Must we all bow down before you tell us. <img src="graemlins/gr_hail.gif" border="0" alt="[hail]" /> <img src="graemlins/gr_hail.gif" border="0" alt="[hail]" /> Mike <img src="gr_grin.gif" border="0"> <img src="gr_grin.gif" border="0">


Johnnie

XLR8NSS

iTrader: (4)

Hmmm...I've got another idea

I know when my belt is loose I don't see full boost. Are you loosening the belt? It seems to fit all your criteria.

1. takes 5 min. under the hood.
2. No initial investment. You will have to buy belts more often.
3. Not limiting rpms.
4. Maintenance every six months or so. See #2

I think this is it.

So what is it? Come on and tell us. Please! <img src="gr_grin.gif" border="0">

Johnnie

just me

there are a few ways of doing this.
You can simply just blow off some boost to atmosphere as some racers do, but you need to have a pressureized maf and need to bleed off boost before the maf for that method.
Another and probably better method is to restrict the blower inlet.
Retricting the blower inlet reduces the load on the unit compared to bleeding off boost and is the more efficient method.
Just do not restrict it to the point you start creating a big vacuum and pull the oil out of the impeller seal.
Paxtons Novi on some applications uses a inlet retrictor method to limit boost.
If you wanted to get mechanically creative you could make a cockpit adjustable inlet restrictor fairly easily using a control cable and sliding inlet valve/plate to block off some flow to the blower.
Or just as easily a cockpit adjustable boost bleed valve.
Neither method is going to be as efficient as a pulley change though.To bad nobody has a modern heavy duty version of Paxtons old VR57 drive system to change pulley ratios automatically.
Steve
www.tech-ls1.com

just me

Forget the loose belt method. You'll burn up belts real fast and that would get Very expensive.
It is also very dangerous to your blower and accessories if the belt comes off and gets wrapped up.

Black LS1 T/A

I got to run back out so I'll chat and check out your comments later, but...

There is no enormous slacking of the belt.
Only a minimal change can make the difference between losing boost and having max boost. It will track on the pulley straight and true, and you are not doing it enough for the belt to sling off.

OK, why is this idea bad??? I don't see why, when just forgetting to check tension periodically can result in degraded boost levels over time... in often barely discernable increments...

I brushed over you guys comments real quuick, but I'm gonna be late...

Jay_@_GWP

HEHE, I've been playing with this one for awhile. If you just blow off to atmosphere, you move alot more air than you would be if it were contained in the blower tract at say 10#'s. Basically it will take alot more horsepower to turn the blower,= not worth it. Mike's idea is okay for just a 1 or 2 # change. More than that you'll smoke belts. I'm working on something similar to what JUST ME said. only mine is not right on top of the blower. at least a foot to do the trick.

You all should be able to figure this one out.

What happens when you induce a vacuum state?
What effects take place?

Answer those and you'll get an idea of what I'm playing with.

Jason <img src="graemlins/z06.gif" border="0" alt="[Z06 Corvette]" /> Hey Johnnie It's pewter!!

XLR8NSS

iTrader: (4)

[quote]Originally posted by Jay_@_GWP:
<strong>HEHE, I've been playing with this one for awhile. If you just blow off to atmosphere, you move alot more air than you would be if it were contained in the blower tract at say 10#'s. Basically it will take alot more horsepower to turn the blower,= not worth it. Mike's idea is okay for just a 1 or 2 # change. More than that you'll smoke belts. I'm working on something similar to what JUST ME said. only mine is not right on top of the blower. at least a foot to do the trick.

You all should be able to figure this one out.

What happens when you induce a vacuum state?
What effects take place?

Answer those and you'll get an idea of what I'm playing with.

Jason <img src="graemlins/z06.gif" border="0" alt="[Z06 Corvette]" /> Hey Johnnie It's pewter!!</strong><hr></blockquote>

Jason, I'm no good at this stuff. Please email me and let me know. Please! <img src="gr_grin.gif" border="0">

I promise I won't tell anybody. <img src="gr_stretch.gif" border="0">

Pewter is a great color if I do say so myself.(Check sig. <img src="gr_grin.gif" border="0"> )

Happy New Year. Talk to everyone on Wednesday. <img src="graemlins/gr_chug.gif" border="0" alt="[chug]" /> <img src="gr_grin.gif" border="0">

Johnnie

[ December 31, 2001: Message edited by: XLR8NSS ]</p>

1dirtyZ

iTrader: (1)

is it different length / diameter inlet tubes to the blower??

just me

so that's what you are doing then, running a loose belt?
Be careful.
This generates a lot of heat and will wear the pulley grooves over time as well the belts.
Ask guys who have sandblasted pulleys to try and STOP a slipping belt.
The pulleys get polished smooth in a few runs from the friction .

I would really consider just making a inlet restrictor to limit your boost and run a tight belt.

Steve

XLR8NSS

iTrader: (4)

Mike, I'm going to have to agree with Steve on this one. If you are loosening the belt to drop boost.

If that belt ever came off and got wrapped around the crank pulley somehow it could cause some serious damage. <img src="gr_sad.gif" border="0">

Johnnie

[ December 31, 2001: Message edited by: XLR8NSS ]</p>

XLR8NSS

iTrader: (4)

Hey Steve

How did Paxtons VR57 drive work?

Johnnie

just me

check out this website.
It's pretty cool with everything you need to know how they did it.

www.vs57.com/

[ December 31, 2001: Message edited by: just me ]</p>