Zoomspeed

I think I've decided to get the dawes devices boost controller. Any reason I shouldn't? Will I need the the basic or the Delux kit?

Thanks

mpetersrx7

Yes several people use these. check out these sites for installation. You should only need the basic kit and then install a bleeder valve in the pre-spool control line.

http://members.tripod.com/modifiedrx...Controller.htm
http://pages.cthome.net/gus/mike.html
http://www.rx7turboturbo.com/robrobi...controller.htm

Zoomspeed

Will I need togo buy anything thatdoens't come with the kit to install it? Is the bleeder valve in the pre-spool control line neccessary?

Zoomspeed

bump

Viper jr

According to the first link in the post from mpetersrx7, yes you need a valve in the pre-spool line also. Check it out, pretty good read.

mpetersrx7

Pre-spool bleeder valve is not necessary but you can really control your transition spikes with it by controlling the amount of pre-spool.

-Mark

ejmack1

ok , i know i have a problem somwhere, the dawes device boost controller does not do anything, i have it on the right line, but i can loosen or tighten it and it ahs no eeffect on my boost, it stay at a constant of 9-11...

cewrx7r1

iTrader: (2)

I have the Hallman $90 version which has an adjustment **** to
alter the spring tension. The air bleed fitting that it came with was way to large for the FD. It was designed originally for Mitsues.

They way mine is connected is: only a hose from the turbo outlet nipple to the valve, only a hose from the valve to the WG actuator, short hose with a small bleed jet from the WG actuator dumping to atmosphere instead of going to the WG solenoid.
If your valve is not adjustable, replace the bleed valve with an adjustable valve and use this to adjust your boost level. But the bleed must be as mine is set up.

Zoomspeed

I remember there being some talk about boost pills that are on the FD. Do I need to remove these for the boost controller to work? If so, where are they?

ejmack1

Boost pills are in the hoses them selves on the older model turbos and the new ones have them built into the turbo's themselves.

wickedrx7

iTrader: (14)

I was thinking about buying a dawes devise boost controler but I can't really see the advantage. why do you need the ball and spring thing?? The stock system uses pills which are the same as valves. The only reason I could see, is the valve might come out of adjustment but I solved this problem with cutting down the T handle and taping it and putting a lock nut on it. This is just a thoguht.

Zoomspeed

Correct me if I'm wrong, but the point is that the Dawes Device valve provides an "adjustable" restriction and the pills have to be drilled out, something that you can't reverse, to change the restriction. I could be wrong though.

Zoomspeed

What size hose do I need? Where is the hose I need to hook it up to? Do I need to remove anything? Whcih way des it go?

Thanks for any help.

Hoainam

Zoomspeed

ok, I got it on. Before I got it on I had a 12-10-12 pattern, but now I have a 12-7-12 pattern. Does this mean I need that pre-spool thing or is something else wrong?

Thanks for any help.

Silver7

what size line did you use? It doesn't sound like a prespool controller will help your problem. By adjusting the prespool, you will either be giving yourself more or less boost on the first and second turbo (depending on which way you turn the valve). Since your boost is equal at 12 psi I don't think it will solve your problem. It does sound like something is wrong though. Please explain in detail or show a pic of how you have it hooked up.

To answer your other question.. the stock boost control uses pills and solenoids which allows air to pass by the wastegate and potentially open it prematurely. The dawes valve holds back all the boost pressure until the desired boost is achieved. This prevents air from passing through the wastegate until you want the wastegate to open. This creates quicker spoolup and and more precise boost control. It is also more reliable since you are not depending on a computer controlled solenoid to control the boost.

Zoomspeed

I used 1/4 inch for one side and 3/16ths for the other. I mounted the controller up by the relays next to the intake. Although, reading over skoobaheads instructions again I realized that I forgot to remove and cap the other vac line going to the same actuator. Could that have something to do with this?

silver7, You siad the the pre-spool controls how much boost I get on the first and second turbo, but isn't that what the boost controller does?

I thought a pre-spool valve controlled how much the secondary turbo spooled before it kicks in at the transition? Is that incorrect?

FD Racer

Definitely remove and cap the other line on the wastegate actuator.

As far as boost control:

-The wastegate actuator ALWAYS controls boost.

-The Precontrol actuator does indeed control how much the secondary spools before it gets online. But by doing so, it also effects the amount of primary boost since it diverts exhuast energy to the secondary. The more energy used for prespool, the less available for primary boost. After both turbos are online, the prespool no longer controls boost.

Here's a story for the young ones tonight:

Before the transition..... the wastegate actuator, the master of exhaust energy, says "here ya go Mr. Primary & Brother Precontol, this will be all the exhast energy i will give to you." Mr. Primary takes the exhaust and starts to boost, then brother prespool cuts in and says "wait a sec....give me some, I wanna hook up my homie Mr. Secondary" So then Brother Prespool sends some over to Mr. secondary to wake his *** up, but in the process, limits the exhaust available for Mr. Primary which lowers his boost. Then Grand Master Turbo Control says "alright Mr. Secondary now that your slow *** is up.....I'm gonna hook yo *** up!" Then POW! He opens the turbo control gate which distrubutes the exhaust evenly to both turbos which the wastegate actuator, the master of exhaust energy, continues to control.

The End.

Zoomspeed

Thanks for clearing that up. I thought if I installed the pre-spool valve I'd just be able to turn that up so my transition wouldn't fall so low.

What exactly is the effect of leaving the other vac line on the wastegate actuator on?

What should I do to fix the low transition?

Thanks for any help.

FD Racer

I take back what i said about capping the other line on the wastegate actuator.

I wanna say that if youre getting an even 12 and 12 in the begining and end, leave the wastegate alone for now and give the prespool actuator more presure with a needle valve. Start with it almost all the way closed. You wont have to open it much. You might find that giving more to the prespool might take some of your primary boost away.

That "other" line on the wastegate connects to a solenoid that is controlled by the computer. This is how the stock fuel computer controls boost.
Pressure is sent to the wastegate actuator from the primary turbo nipple outlet through a vacuum line. Then the pressure passes through the pill (or dawes device, needle valve, or electronic boost control, etc.) on the way to the wastegate actuator. Then the "other" vacuum line is used to bleed off pressure inside the wastegate actuator to the solenoid. The more the solenoid opens, the more pressure is lost, and the less the wastegate will open.


As far as the precontol, the more pressure you send (and / or the less pressure you bleed) the more prespool you will get. Be carefull, the adjustments on needle valves are sensitive.

The stock boost control will actually help you keep the primary and secondary boost at the same psi. It knows that the precontol is diverting exhaust energy away from the primary, so it opens up the solenoid on the wastegate actuator to give more exhaust durring primary boost. Then, after the secondary gets online, the solenoid closes up some since the secondary turbo is no longer "wasting" exhaust energy.

I'm tired...i hope i'm not rambling on ....


I thought you were going non-sequential? what happined?

Silver7

did you really use 1/4 and 3/16 inch vacuum line? If you did then that is your problem. Use 6mm all around and zip tie it. Leave the other vacuum line on the wastegate alone. You can cap it but either way should work fine.

Flybye

Actually, the stock ECU doesn't even control boost. It opens and closes the wastegate and prespooler like a dummy not knowing what boost is actually coming out.

I was using the Dawes valve before I got the PFC, and it worked great! I disconnected my solenoid.

The PFC actually does a good job at controlling boost. When I hooked it up, I reconnected my solenoid and yanked the dawes out. Now I just ended up using a manual Home Depot Racing valve to act like a pill.

Silver7

This is the exact reason why a boost pill or HD valve needs to be used to control boost. The ecu sets the solenoid at a specific duty cycle. From what I understand the M2 and Pettit ECUs adjust this duty cycle to accomodate for engine modifications. I know my haltech software can control the duty cycle and I assume the PFC can also be used to adjust the duty cycle. What you are forgetting is that the way our turbo control is setup, it allows for pressurized air to pass through the wastegate which can potentially push open the wastegate and decrease turbo spoolup. The dawes valve holds all pressure back away from the wastgate actuator until the desired boost level is achieved. In my opinion this is a more precise way to control boost.

Zoomspeed

FD racer,
I'm still gonna go non-seq eventually. I want to get a hi-flow or MP before I go non-seq but I won't be able to get one for another month or so unless I find one super cheap.

Next weekend I get free I'll change the hose size to 6mm and I'll give the pre-spool vavle a try. I'll let you gusys know what happens.