ckathens

I'm about to purchase a Tial 38mm Wastegate for my '86 to go with the LIndsey MBC I just purchased. I'm doing a venturi and CV delete at the same time, so the MBC will be regulating the boost.

If I run the Tial 38mm WG in dual-port mode, does it matter what spring rate the Tial has? If its operating in dual-port mode, the pressure on one side and the vacuum on the other can change the boost pressure at which the WG opens, right? So if I buy a Tial with a 0.6 spring in it, can't i just use the MBC to get the equivalent of a 0.8 spring or even a 1.0 spring? Is there any advantage to getting a 0.8 spring over a 0.6 spring if I've got no other "mods" and don't plan to try to break the 300hp threshold?

Finally, where should I purchase the Tial? I've found EuroParts and SFR both have pretty good prices. Pauertuning no longer sells the Tial. Are there any other reputable dealers that people here use? Thanks!

theedge

The only thing to keep in mind is that the spring determines the lowest boost pressure you can run. Other than that, no real difference unless you have crappy boost control.

MySwiss sells the Tial and the adapter plates as a package if you want.

87944turbo

This is probably the best information I have found on the subject. I had the same questions. https://rennlist.com/forums/944-turbo-and-turbo-s-forum/120892-wastegate-spring-question.html I have a 46mm Tial and the PO used to have it setup for 18psi so I had a 6psi spring and a 13psi spring. Have used both springs in dual port mode and the higher spring rate was clearly better. Faster spool and held power better up to redline.

azmi951

I have a new in box 46mm tial for sale. 1 bar spring. $430

ckathens

Thanks for the messages guys! I'm making my order tomorrow from EuroParts.

skene

I just put one on with a 38mm with an .8 bar spring in single port mode and hit 16psi easily in 2nd. I didn't have time to do any more testing and I've got a vacuum leak to fix, but it looks like it'll hold well.

smarlow2

I have a 38mm dual Tial with a .8 bar spring on a 26/8 turbo. I ran it at the track last weekend at 18psi on 100 octane race gas. Ran like a scalded cat and no overheating or other problems despite track tempature of 120 degrees.

jacklet

you better get some chips or you're likely to hit the dreaded overboost protection

smarlow2

I am using Vitesse chips and they are doing a great job. I am running around 14-15 on street gas for every day driving. I also have a widefire gasket and a test pipe.

skene

I've got vitesse chips in mine too. I should probably put my mods back in my sig sometime.