external wastegate spring

[Turbolaser4528]

hey guys i searched a ton and didnt get exactly what i was looking for so i decided to post.

i have a 40mm external wastegate and a turbo xs hpmbc. my boost is topping out at about 20 psi even with the boost controller at the lowest setting. I just took apart my external wastegate to find a black spring with about 3 coils in between the top and bottom of the spring. i saw that a purple spring has a setting of 20 psi but this one is black, plus its only one spring in there not 2.

so im thinking either my mbc is broken, or the spring is making the car run at 20 psi. Should i take out the spring completely? can i hacksaw it to make it smaller? should my boost controller hook up the the nipple at side of the wastegate, not the top?

just trying to troubleshoot this and run anywhere from 10-15 psi, any help is appreciated guys thanks

 

[andymoraitis]

Removing the spring or sutting it won't solve your problem. It sounds like your MBC isn't hooked up properly. If you're using the top port on the wastegate as a bleeder source for the boost controller, you have it backwards. Switch it to the side port (the top port is for an EBC).

Also, what brand of wastegate did you buy? I've never seen black or purple springs on a Tial and was wondering if you had some no-name ebay special.

 

[Turbolaser4528]

im thinking it is an ebay special because the guy i bought it from just said it was a 40mm external wastegate

my mbc IS hooked up to the side port i was just wondering if i had it hooked up wrong which i guess i didnt.

also on my maft i turned the idle to 0 instead of 1 since the car was idling at about 2k ( i have crane cams if that matters )s will this be better for my car or will it not even start?

thanks again, especially andy haha

 

[Turbolaser4528]

anyone?! i mean i know its thanksgiving and all but my car is sitting apart in the garage because im waiting on a helpful response. Should i just test drive it without the spring? can i use a spring from something else?

and what about the maft setting mentioned above?

whoever helps me out gets a free beer!

 

[eclipsegsx1736]

Have you tried not using an MBC and running a line directly from a boost source to the side nipple on the wastegate? That will set the boost to the spring pressure of the wastegate.

 

[Turbolaser4528]

i was thinking about it when i thought my mbc was messed up, ill go give it a shot right now! thanks for the reply

 

[vintagemuscle]

Have you done a boost leak test to see if the diaphram on the wastegate is leaking? The diaphram on my turbosmart wastegate was leaking and my 10lb. spring wasn't opening the wastegate until about 23psi.

 

[Turbolaser4528]

i bypassed the mbc and tested it out a few hours ago. It ran at about 14 psi and then hit fuel cut after a few seconds, so i guess the spring is a 14psi spring because the line goes right from the intercooler pipe to the nipple on the wastegate.

i wish i had a smaller spring so that i could run maybe 10-12 lbs of boost but i guess i will just find one. this might be difficult because it seems as though my wastegate is an ebay knockoff haha but if anyone knows where to get a spring let me know.

would a regular tial spring work?

 

[andymoraitis]

I have a .8 bar (11.6 psi) Tial spring I'm not using from a 38mm. If you can find out if it'll work by contacting an ebay vendor with a gate that looks like yours I'll send it to you.

As to why your MBC wasn't working, it's more than possible that you had the lines for the boost and wastegate sources reversed.

Let me know,

Andy

 

[Turbolaser4528]

it should work, i asked around and it seems as though it would. if your not using it and want to make my day id really appreciate it

 

[andymoraitis]

PM me your name and address and I'll send it out as soon as I can.