11 Bravo

iTrader: (3)

I'm trying to learn more about FI stuff. To adjust boost on a supercharger, you change a pulley, right? How do you adjust boost on a turbo? Do you have to retune the motor when you change boost?

MacGyver

iTrader: (5)

Turbo setups use whats called a wastegate. It bleeds off any boost over the set limit on the exhaust side of the turbo system. It bsically controls how much exhaust flows into the turbo thus limiting the max RPM of the impeller blades.


Will

2FAST4U

yes on a turbo setup you adjust the accuator rod that opens the waste gate and on super charged car you need to change pulleys, however there is a little waste gate thing on the Procharger kit but it is preset for pressure. I have both Incon Twins on my 02" and ProCharger D1-SC on my 92". <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />

zturbo

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif"> To adjust boost on a supercharger, you change a pulley, right?</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yes, correct. You change the pulley to spin the impeller faster or slower... Depending on what you want.
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">How do you adjust boost on a turbo? </font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Wastegate, It releases exhuast pressure out of the turbo so as to not force the impeller to spin harder against the resistance...
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif"> Do you have to retune the motor when you change boost? </font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yes, I would retune.. Reason being is the car is pushing more air in than with a lower or higher setting so the tune will be diff.

Pic of wastegate before the turbo (headers, wastegate, turbo.
Hope this helps some

JimmyKash

There is another clever way how to adjust boost with a blower. Someone on this forum did it. I think it was 99 black t/a or ls1 t/a 99 something like that dont remember

basically he put a ball check valve on the inlet of the blower to bleed off some air so it wouldn't produce so much boost or something like that.

Neat designed that worked

11 Bravo

iTrader: (3)

Okay. Until I started reading up on this site, I always thought you could control turbo boost by turning a dial inside the car. Just adjust it on the fly. Guess that is not the case?

Blkknight

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 11 Bravo:
<strong> Okay. Until I started reading up on this site, I always thought you could control turbo boost by turning a dial inside the car. Just adjust it on the fly. Guess that is not the case? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yes you can. I have no idea how it works but it is possible. I have heard though that the manual boost controllers are more precise though.

Adam J

chasgiv3

iTrader: (1)

Many people add an electronic boost controller to verify the actual boost and adjust the wastegate accordingly. But remember this.....your engine management system needs to compensate for the extra boost with less timing and more fuel as boost goes up. So you need to deal with these issues also.

MIGHTYMOUSE

iTrader: (59)

11bravo, on a turbo you can adjust it on the fly

after you set your wastegate normal boost setttng, you intercept that vaccum line with a metering device.. the more you close off the line, the less boost the wastegate will see, so the higher it will let you boost

there are a ton of boost controllers out there, manual ones, electric too.. this is the one i have but you can get a cheap one for less than $10 from a hardware store for basic funtion.

http://www.turbosmart.com.au/boost_c...electronic.htm

chasgiv3

iTrader: (1)

Couple of clarifications here.

There are different types of wastegates that actually control exhuast flow feeding the turbine (wheel on the exhuast side of the turbo) section.

1. Integrated: usually has a flapper valve within the turbo to either force pressure to the turbine or allow it to bypass it (waste it) and allow the pulses to leave through your exhaust system. The flapper usually has a pivot point that has a bar that protrudes to the outside of the housing. This bar is then connected to a rod which is then connected to a diaphragm which has a spring in it opposing movement and an output boost reference that will try to move the rod and thus move the flapper valve.
2. External: usually is a part that has a valve with a short rod,diaphragm and spring. It also has a boost reference. All of this is enclosed in a small housing. You also have to run a section of pipe from the turbo header to the wastegate. When the wastegate opens the valve the pulses/pressure bypasses the turbine section and leaves via your normal exhaust system.

The problem with JUST wastegates or JUST bleeding off the pressure is that they will not lock you into a pressure. Springs tend to change their rates based on temperature. So you could vary your boost by as much as 5PSI. That could make a difference between keeping your motor alive or turning it into scrap metal.

AzzHauler

iTrader: (3)

I'm currently trying to come up with something similar that I can use on my ati kit. I was thinking a bov that I could set to open at say 9psi, and have the sc pullied for 12 or so. And just disable the bov when I want more.

1slowCamaro

I tried that and havent gotten it to work. I think its cuz a BOV is usually activated by vacuum and is different from a wastegate.

red ws6 99

Azzhauler, just get a relief valve and set it for 9 psi. You will have to figure out what flowrate you need, but no big deal.

Gary

<small>[ February 12, 2003, 09:36 PM: Message edited by: red ws6 99 ]</small>

Blown Hawk

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by AzzHauler:
<strong> I'm currently trying to come up with something similar that I can use on my ati kit. I was thinking a bov that I could set to open at say 9psi, and have the sc pullied for 12 or so. And just disable the bov when I want more. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I was gonna start a post about this very thing. I was thinking how the turbo guys keep talking about how they can achieve max boost and subsequently max torque at low RPMS(3K or so). But the blower guys have to wait till the supercharger spools up to reach max horsepower just before they shift. What if we had something like a waste gate for the already pressurized air. If using a 12 psi pully we reach 8psi by 4K rpm and then some sort of bleed off to maintain that 8psi till we shift, then we'd be set.

The only draw back I can think about is increased intake air temps due to extra air being compressed. Although theoretically if you released the pressure after building it up it should heat up and then cool right back down.

Any thoughts? Let me know what you find out Azzhauler.

BH

AzzHauler

iTrader: (3)

I checked a little on a relief valve like red ws6 99 was talking about. I saw a pop-off valve(same thing) on greddy's site for about 140 I think. And on hks' website, they have a race bypass valve that they said can be used as a pop-off if you hook up a pressure(boost) line to the second port on it. That was like 160+ I think. I'm lookin for cheap though <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> . So I'm gonna try to do like Jimmy was saying in his post about a homemade valve. I picked up a few parts at home depot the other day (~8 bux <img border="0" alt="[angel]" title="" src="graemlins/gr_angel.gif" /> ), but I need to find a place where I can get various springs from to use. And of course, all the online sites I found, are geared toward mass-produced, industrial stuff. If I can make it work, looks like it could be in the sub-$20 range. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> Might not look real pretty though. But that's later.

On a side note, I believe that Black LS1 T/A has some pics/write up on his site about a boost limiting device he made.

White_Hawk

iTrader: (3)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Blown Hawk:
<strong>But the blower guys have to wait till the supercharger spools up to reach max horsepower just before they shift</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Lucky for me I hit peak torque at 4400 ( dyno ), that's what really counts. The supercharger is always spooled. The difference is that the bypass valve flows air around the blower when you are under vaccuum. On my car, below 2200 or so the car is sucking extra air past the blower. Over 2200, the blower is pushing more air than your car needs and the valve bypasses it to the front of the blower. When you stomp it, the bypass closes and all the air goes in the motor. That is different than a blowoff valve, which only opens when a certain pressure is reached.

My car sees 7 psi at 6000 rpm's. But it's not like I see only 1 psi at 2000, 2 psi at 3000, etc..., it has 5 psi by 4400 rpm (maybe less rpm but I haven't looked that close). The blower has a fixed amount of pumping, but the engine is taking in more air at higher RPM's, too, that is why the boost is not a 1:1 linear rise with RPM.

There is no doubting the abusive amount of torque you see down low on a turbo, though, it is just downright sick on some cars ( <img border="0" alt="[worship]" title="" src="graemlins/gr_hail.gif" /> Rob Raymer).

-Geoff