mortymower

I bought a tial 38 a while back and love it, but I have the .8 bar spring in it and I usually run about 14-15psi on the street. I am getting into Auto X and I find that with the other mods i have, 14-15 is WAY to much for tight Auto X tracks. I can turn it down to .8 bar (about 10 psi) and that helps control the swing out, but on the smaller courses I still feel like I give it throttle and when I begin to hit high boost I have to let off to keep from being sideways.

I saw that tial makes springs down to .25 bar, is there any problem with putting in a .25 or .5 bar spring and turning boost down to 5-6 pounds while I am learning auto x and then running 15 on the street, or should I have a spring close to what i normally run (like i do right now) Thanks

rhesus

what are you using for fuel control?
if you're just changing the boost with no change in fuel, you'll be running rich.

reno808

if you have chips set for 14-15psi and your in a auto-x boosting 10psi or lower you can run the risk of washing your cycl., but then again that is an extreme case. learn how to drive with the 14-15 by playing with the throttle and left foot braking, heel and toe, etc lol.

TurboTommy

Just because you're running less boost than what the chips are set for doesn't mean you're gonna run rich. Your air measuring device will give a signal of less air flow and fuel will be delivered accordingly.

mortymower

I have a vitesse maf with proper chips, boost gauge and wideband, I am fine all the way up the powerband in terms of AFR, just wondering if I put a lower spring in can I still hit 14-15 everyday without stressing the wastegate/ lines/ boost controller, etc.

Auto_Werks 3.6

You may be ok with the vitesse true maf but... I still would not put a .25 bar spring in. . MAYBE I would go .5, but you would really be doing yourself a favor if you tried to learn how to modulate it.
You should also be aware that with a .25 bar spring, the exhaust backpressure may start to become your enemy. IE exhaust pressure MIGHT open the wastegate. I don't know that it will for sure, and that also depends on what turbo you are running.
If it wouldnt hold boost, you could run a line straight from the top port to the intercooler pipe, and regulate the pressure to the side port. Note this is backwards from normal, and if it had a .8 bar spring it would NEVER open. I can't imagine that this would be harder on the diaphram, because scimilar conditions would exist if say you had your controller set to release at 18psi, and you drove the car all day at 14 (partial boost pulls). Thus, always 14psi or some existing pressure differential in one side of the WG vacuum chamber.
I would also be concerned that having to hook the gate up backwards might royally **** off an electronic boost controler. I don't know, I have never played with one.

mortymower

I might just try and learn to modulate I guess... darn

reno808

just have fun and stop worrying about boost.

tconn

As well as learning to modulate you might consider adjusting the rear suspension for less oversteer.
When I used to autox I found it was helpfull having the power come on quickly. I adjusted the suspension to work with the power.

Luis de Prat

What was most effective to accomplish this? Different rear sway bar? What setting on your coilovers?

tconn

I started with the softest settings on the coilovers and sway
bar. I then increased the rates until the understeer was dialed out as much as possible but the rear more planted.
I always found it helpfull to have the rear a little loose
for autox. I was able to swing the car around quicker in the tite turns.
I was able to win the class championship the year I got serious about it.

Techno Duck

If you have an adjustable rear sway bar like the 19mm M030, set it at the softest setting. A large rear sway bar makes the 'peg leg' issue worse.

RPHARRIS

My suggestion is to learn to drive with it at 14-15. Want less power? just don't push on the gas as hard. Learning to hold back was a big step forward for me in autocross. Even driving a Miata that had 110whp on a good day and a fairly well sorted suspension, my natural tendency was to exit every corner with a big nasty powerslide.

I still remember my first autocross, when on my final run, in the midst of a downpour, the vacuum hose to my Tial 41mm wastegate came disconnected. It certainly wasn't my prettiest run but it was my fastest by a decent margin.

mortymower

I have the 968 M030 bars so I will try and set the rear at the softest and see how that helps

hally

I could not fully eliminate the boost control occilation with a 0.8 bar spring on the Tial, where as with a 1 bar spring it is super smooth (running 15psi dual port via the black **** manual boost control valve setup)
So from that point of view be wary about going to a softer spring than 0.8 bar. Its a cheap and easy mod to try though so you don't have anything to lose giving a softer spring a go i guess as long as your a/f is fine as others have highlighed.