external wastegate users...spring question

[93ty475]

What determines which spring we need to run? I can't find any good info on this....assuming the spring is related to base boost psi, will a 15 psi spring give quicker spool than a 5 psi spring? Is a 10 psi spring a good all around choice? I'm to be installing my blitz, electronic boost controller.... I plan to run 15-16 psi if possible on the street on a pte stealth and maybe crank it up to around 22 psi on special occasions using alkycontrol....I plan on using a TiAL 38mm gate on the crossover, not on the downpipe flange ...any other suggestions?

also, how annoying is the sound of an open external wastegate?....the archives here are full of people comments on how annoying the sound gets....anyone have a video that might demonstrate the sound? Just hard to imagine that any turbo related sound could be that bad....This won't be my all day driver, just a night stalker...

 

[bezerk]

Re: external wastegate users...spring question

i have that 10PSI spring in mine, used a manual boostcontroller to control the boost behind 10PSI.
worked great.
but it's a 40MM

 

[spooldup]

Re: external wastegate users...spring question

a good electronic controller like the profec b will give you 120% more boost than your spring is set for. Example 10lb spring = 22psi of boost. You can get it to go a little further but that will depend on your controller and how well it can control the boost. The profec b begins to swing slighltly at around 24psi otherwise it's rock solid. The size of the gate will be factor as well. A smaller gate will not regulate boost as well as a larger gate.

 

[nightdiver]

Re: external wastegate users...spring question

Its the combonation you got. If you use a small like the stock turbo a ten psi spring will give you 4-5 psi boost. Thats because of the exhaust back pressure that you have to calculate. If you use a bigger turbo it will be 10 psi boost but it will come slower . Its the crancking point that opens the WG spring earlier. Then you buy a boost contoller and a 40+mm WG and youre done .

Get the 15 psi spring for your base boost or the back pressure will open the gate and you wont to able to reach 22 psi. I use a 22 psi spring and i can regulate boost up tp 29 psi very easy.

 

[93ty475]

Re: external wastegate users...spring question

thanks for the input guys....sorry for the delayed response...A friend of mine sold me a brand new beautiful 44mm TiAL wastegate...looks huge....He used it only for mock up purposes on an evo build and never ran hot air through it....it came with a .9 spring....He has an assortment of different leftover springs that he's aquired over time and offered to let me swap for another one at any time....It's the v-band type and he gave me a hell of a deal on it....I plan to mount it on the crossover even though it seems like a heavy thing to hang on our crossovers....he also welded a piece of 1 5/8" (304ss 8gauge) to the flange that I'm going to c-notch in order to install it on the crossover....I hope this works....

 

[93ty475]

Re: external wastegate users...spring question

pics...

 

[crashing_sux]

Re: external wastegate users...spring question

Never heard the %120 bit before. I was hoping to have a spring setting base boost to around 5psi for launching and then have the boost controller push it up to around 18psi on pump gas or 25ish on alky/race gas. Guess that's not possible then?

 

[Maxtor]

Re: external wastegate users...spring question

I have a 15lb. spring in mine right now. The lowest it will go is 17psi, and the highest it will go with my Blitz SBC ID3 is 25psi. I also have a 20lb spring that I put in before racing that allows me to run 30psi.

Generally, it is a good idea to set the spring closest to the boost you want to run. This will give you faster spool, and will usually give you more solid boost since your boost controller will have a smaller window to have to control.

 

[Ian Turgeon]

Re: external wastegate users...spring question

WIth my stock turbo and TD06-20g 12cm2 my Innovative progate on the crossover. I've been using a 15# spring since day one, and it will control 15-20 easily, Havn't pushed it any higher but its solid with the SBCID I'm using, I'd be amazed if I couldnt run 30lbs, but I guess I may have to look into it after reading mark's post.

I havn't seen that style Tial before, interesting. The key is to get it as close as you can to the base boost you want to run, generally the bigger the gap between your spring pressure and your boost level, the harder it is to control.

BTW I love the sound, its much different with a boost controller then a bleader valve. Bleader just gets louder as you go faster, with a controller, you can hear it working, rrrwwwaaa rrrwaaaa rrrwaaaa as you get near your target boost level.

Its only annoying if you dont like hearing your truck when your going fast.

 

[crashing_sux]

Re: external wastegate users...spring question

Actually, come to think of it I have an 8lb spring currently and have had no problem controlling the boost up to 22lbs. That's quite a bit past %120, is the 120% thing for internal wastegates? Another question while I'm at it, I have a buddy with an internal wastegate and he was under the impression that threading the rod that comes out of the wastegate diaphragm further in or out would affect the base boost. Is that true? I thought it only affected how far the wastegate opened.

 

[crashing_sux]

Re: external wastegate users...spring question

FWIW, I just read through my boost controller manual again and they have a "guesstimate" table used for first setting up your controller if you have a 7psi spring in. Here's what they show for different settings (0-99):

30 = 10psi
40 = 15psi
50 = 19psi

I wonder why they don't show more than that in their charts? Maybe that's the point after which they don't think they can control it adequately? Probably never know as they are completely unresponsive to their support email on their website.

 

[93ty475]

Re: external wastegate users...spring question

BTW I love the sound, its much different with a boost controller then a bleader valve. Bleader just gets louder as you go faster, with a controller, you can hear it working, rrrwwwaaa rrrwaaaa rrrwaaaa as you get near your target boost level.

Its only annoying if you dont like hearing your truck when your going fast.

that's what I wanted to hear... ....I can't wait....I guess the noise can totally be regulated with your right foot....

 

[93ty475]

Re: external wastegate users...spring question

I finally got around to welding the wastegate flange to the crossover last night....I used a spare low mile crossover that I bought from someone here a couple of years ago....we tig welded a short piece of 8 gauge (around 1/8" thick) 304 stainless pipe to the w/g flange....then tig welded the pipe to the crossover....came out really nice....I used a plasma cutter to c-notch the stainless pipe and to cut the hole in the crossover.....I used a high speed tungsten carbide cutter to shape the hole in the crossover...further cleaned it up using a white silicone grinding stone....I bribed my experienced tig welding friend of mine with a 6 pack of Mike's Hard Lime to do his thing.....here's a small gallery with some close up shots so people can further understand what's involved in doing this..... If you look at the pics that show the inside of the pipe, you can see how clean and deburred the crossover is....


welded crossover






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