soundengineer

iTrader: (16)

that is not very accurate or consistent...
I have a buddy who does that...keeps the valve in a different spot, but same thing.

I can tell you that boost pressure was all over the place on the data logs while we were tuning his setup.

Forcefed86

iTrader: (4)

Then I would say he didn't do it correctly, or his gate isn't setup properly. I'll post some LS logs when I get home. My boost is very consistent. And I've done it this way on many many setups.

Here is one of my 2.0 liter running a huge slow spooling turbo. As you can see though once it hits 26psi it stays right at 26lbs. The LS maps all look similar, they just get into boost faster and stay within .2-.3 psi of the target.

Orr89rocz

iTrader: (13)

My only gripe is that the adjustment for increasing boost isnt exact. There is an offset of somesort that gets worse as you increase boost.

For instance i have 13 lb gate spring see 13 psi. If i want to use the ams500 to go to 17 psi you would expect dialing in one of the stages to 4, which should add 4 to get 17 but it doesnt work that way. I need to dial in more like 10 over. And if you want 20 psi you have to dial in even more.

And what works on the street doesnt work on dyno. Dial in 10 over on street may give 17-18 psi but dyno needed dial in of 20 or whatever it was. Point is the ams controls boost well but takes experimentation to find what settings gives X boost. Kinda disappointed with that.
I reference off manifold port for pressure i wonder if co2 would be more accurate for dial in settings? I read posts saying it still has offset

Heavy H.P.

Thanks for all of these replys and please keep em coming. Its a learning experience for me and im looking forward to soaking up as much of the knowledge as possible.
Should be starting on my setup next month so I'm trying to make sure I understand everything.

soundengineer

iTrader: (16)

target psi is not the boost value...its the target applied to the dome, and dome pressure needed to keep the gate closed will be different than the offset in boost....it effectively changes the spring rate not the spring pressure...
meaning the spring pressure might be rated for 13psi, but the rate is how much difference there is from open to closed in actual weight...
adding 10lbs to the spring rate is not adding 10 psi to the spring value


also there are other settings other than just the main boost value....
you have to be willing to explore those other settings

try raising the Rate/PSI per second value...(default is only like 5?...and you can set it up to 100)
this will make it respond quicker and more accurately...but you can go too far and it will become unstable.

also, if you have a big spring(13 psi is a pretty big spring to the controller...), the controller will have a harder time because it has to push a lot harder to achieve results..
putting in a lower spring and using the controller to do all the work is how it was designed to work the best


also, manifold pressure doesnt control very well..especially on a bigger spring..
you need 30-40psi above desired boost to accurately control boost..

Orr89rocz

iTrader: (13)

That was my issue. I wanted my 6 psi springs on street but i was told you shouldnt go over 2-2.5 times spring pressure for boost. So i wouldnt beable to go over 12-15 psi or risk having control issues. Well on the dyno i saw 8 psi on 6 psi spring and was not able to go over 17. So 2 times worked in that scenario, so i went more spring to hit big boy boost to make the big numbers. It worked the 13 spring saw 15 on dyno and i got to 24 just fine before stopping at 1009 sae hp. I think theres more left for boost but i was already dialing 30 over. 40 is the limit and might only give 2-3 lbs more if that

Makes more sense that the dials mean pressure applied to gate top, and not desired boost. Either way i will have to record what targets give what pressures for racing

Havent tried ramp rate feature but never needed it. Its set to instant boost no ramp, and car has hooked fine at lower boost levels. Havent tried higher. I'll ramp as required then

Thanks for the input.

soundengineer

iTrader: (16)

hardcore racers throw in a 1lb spring and just use the boost controller for pressure...upwards of 40 psi with no issues

its all a matter of having a fixed pressure source like co2

Orr89rocz

iTrader: (13)

Yeah that was likely going to be my next adventure. Either way still, i have to experiment with targets to get desired boosts and keep a chart in the car lol

soundengineer

iTrader: (16)

thats the beauty of it...
the less spring pressure you use, the more accurate it is...then its top pressure vs bottom pressure...and no spring pressure to add into the mix.

khenry

iTrader: (3)

Without hijacking your thread. I have an AMS 1000 boost controller new in a box for sale it cost me $1,000. I'll sell it for $850 and pay for shipping in the lower 48. PM me if interested.

thendawg

The thing is, were talking about a street car here, c02 isnt exactly practical on a street car... I was thinking about running the AMS500 for my GTO, but C02 is definitely out of the question. In the past (on other cars) Ive used an AEM TruBoost with good results (typically stays within .5-1psi of target) so I may just stick with going that route if the only way for the AMS to be reliable/accurate is to use C02.

Forcefed86

iTrader: (4)

Use a small pressure pot with a check valve tapped into the exhaust pre-turbo. Then regulate it down to 40-50psi.

Forcefed86

iTrader: (4)

I wouldn't spend the money on a true boost or any other electronic boost controller for a street car. This $15 setup works VERY well.

skinnies

iTrader: (33)

Use on board air, $150 bux.

I wouldn't use any time based controller for a true street car, front wheel speed is the only way imo on something you plan to drive and have fun with on the street.

There's a reason we can run fast on pure street tires(not drag radials).

Orr89rocz

iTrader: (13)

Dont confuse what i was complaining about as being unreliable or inaccurate. The ams is very accurate and repeatable. Its reliable without co2. It just takes some testing to find what values give you proper boost levels. Co2 just gives you abit better control because of its higher stable source pressure.

Orr89rocz

iTrader: (13)

And co2 doesnt seem expensive or bad to have. Cant you just run any paintball gun 12-20 ounce bottle from sporting good stores and a 50$ regulator valve and that will last many passes before requiring a 3-5$ refill lol

soundengineer

iTrader: (16)

*edit* had accidentally said 5 gallon.. meant 5lb***
get a 5lb Co2 tank...(lasts a LONG time)
I bought mine from an aquarium supplier for about $55

http://www.aquariumplants.com/CO2_Cy...prices_p/t.htm

bu the pressure regulator from any place that sells co2 regulators for kegs

also, you can run compressed air if you want...(this is my eventual plan for my car)
just buy a decent 12v 100% duty cycle air ride suspension air compressor...
Like the ViAir 450c series....
use it to fill your tank to 145 psi...
endless air supply...and it can mount on the underside of the car or in any little space you can find for it.

Orr89rocz

iTrader: (13)

How heavy is that?? Biggest i'd want is nitrous bottle size

soundengineer

iTrader: (16)

5lb co2 bottle is the same size and weight as a 5lb nitrous bottle, it just as a slightly different valve design
holders for the bottle depend on how you want to mount it...they dont weigh anything worth mentioning usually

the Viair 450c weighs 11lbs....
so again...not very much


they sell a version that comes with a little 2.5lb tank..they market that one to use with Air nailers and Air Riverters for portable construction work.

thendawg

How long will c02 last in a street car though? Im not talking a "street car" but a real street car where you drive it several times a week and each drive consists of a few wot pulls through the gears for fun.