MM951

So I never noticed this, but while experimenting with higher boost on a simulated race track my friend noticed if I set it at at 18 psi (in 3rd gear) by 5-6K rpm it has fallen to maybe 16 psi.

I have a fresh engine, Vitesse MAF, Tial 38mm, and a turbonetics 60-1 hifi. This should not happen, right?

I want to look at the wastegate, but I have never heard of a tial failing, ideas?

lee101315

I would check for boost or exhaust leaks.... even the tiny leaks can get pretty big at 18psi

ryanm6100

I may be wrong, but does the Tial have several different boost springs to choose from? If so, it's possible you need a stronger spring for the higher boost levels.

TurboTommy

I'm not familiar with the configuration of the tial; does the exhaust pressure in the crossover contribute to the opening of the valve?
How are you controlling the boost?

adrian1

Mine is doing something similar and I have 300 hp kit.

CarbonRevo

Mike- Never got back to me on the wastegate pipe. Did it work? Kind of like you just fell off the face of the earth until now??

Hope everything worked out in the end. Did you ever get the MO issue resolved?

TheRealLefty

There could be number of possible issues here above and beyond the WG or line leaks, including turbo size and WG boost control devices. Important to know also if this is a new condition or one built into this car's current configuration and just now being uncovered.

One of unique parts of the 951 experience is how important (and potentially rewarding) all of the boost management work can be. In the "old days" HP was built from the bottom up and required significant machine work and improved bits inside the long block. Extreme performance, obviously, still requires same, but the realm of 250-270 hp can be reached in a plain jane 951 just through mechanical and electronic bolt-ons.

MM951

Should probably give more details:

38mm Tial with a 9 psi spring
Black **** MBC mounted in cabin (not exposed to engine heat)
2.5" exhaust (no cat) and stock downpipe

I do have some exhaust leaks ( but will be taking care of them soon - again) and a slight intake leak (vac is down to 17-18" from 20" warm idle) that I'll take care of soon (never enough time!!)

I doubt the turbo is running out of steam, anyone else with a 60-1 hifi care to comment?

CarbonRevo

I believe Jon has a similar setup to you. Might ask him or see if he chimes in.

choinga

Do you know for sure that there is a leak? There was a thread with a poll a while back and an overwhelming number of folks were at the 17-18 at warm idle.

blown 944

Running in Dual port??