Lemikson

Like title is saying is anyone running or familiar with what should be the spring rate for Tial F38 wastegate with stock DME chips and without any boost control upgrade (manual or electronic)?

I want to upgrade exhaust to 3” from downpipe flange to the end. With HF CAT and Magnaflow Muffler at the back. At the same time want to upgrade 30+ years stock wastegate into Tial F38. I was planning to put 14 psi spring rate but looks like it would be way too much of boost with the stock chips.

Any advice would be much appreciated.

Dave951

If you can afford the expense save yourself the spring rate trouble and purchase a black **** MBC.

With that out of the way the stock boost on the 951 is 11-12psi (.75 - .85 bar). Your nearest choices are large yellow spring at 10.15psi or large red at 11.60psi.

Also remember the Tial 38 is not a direct bolt up replacement. You will need either adapter plates or modify the exhaust for v-band..etc

Lemikson

Thanks Dave. I am hoping someone runs this exact set up so I can get the info first hand. Honestly, slowly I am cooling off from this idea as it looks like it is not proper way of doing it.

From what I have found so far on Rennlsit/Pelican about Tial is when properly done it requires 2 port boost control. And my way of executing this will preserve single port CV boost control. I also found some forum members stating that even with 7.25 psi (0.5 bar) spring rate they had 17-18 psi max boost – that’s something I don’t want to run with stock chips.
Since Tail only comes with 0.3 bar softest spring (3.53 psi) question is will I be exceeding 12-13 psi max boost with such set up - which again I don't want do it?

Dave951

The easier and IMO better solution is to remove the CV from the equation and go with a simple dual port MBC (like the black ****).

At the minimum for the install your running 3 vacuum lines and a tee to the MBC and capping off the line that runs into the j-boot from the CV. The majority of the old components can stay in place if you choose.

fast951

If you are keeping the stock DME chip, then get the 7-8 psi spring. Or risk the overboost protection kicking in.

raleighBahn

You will be bitterly disappointed spending money on an aftermarket wastegate on stock chips and CV. Almost certainly it will provide too little or too much boost with no recourse. Don't do it.

Provided you have a boost gauge, an easy way to prop up an old stock wastegate is the LR boost enhancer. It's a fine step for understanding what to do next. If you can get an AFM chip (A-tune or vitesse), it will be a lot safer. Shim the WG if you find yourself wanting to squeeze more out. It's a very old mod, but it worked and still does for the use case.

I ran A-tune with LRBE before I went to Tial+EBC (still with a-tune) and it was a great intermediate step. The AFM chips will adapt as you go. However, I wouldn't advise any of it without boost/afr gauges.