Shoptalkforums.com

Is there a limit of how much psi will go into a cylinder.

My motor has 66mm from BDC to TDC.
How will a motor complain about the cylinder being too full.
Broken rings maybe
Boost escaping out the exhaust valves due to cam over lap
If boost escapes due to cam over lap a motor should be pretty safe if the tune is there.
I ask because my motor complains with higher boost by popping out the exhaust pipe.
Maybe it's spark blow out.

I have just fit a petronix big cap distributor and flame thrower coil, this is an improvement over the small cap, standard coil I had previously.
Motor is stable at 1 bar, but my turbo is capable of more, so I wanna use what it can do.

Spark blowout would be my guess. Maybe try tightening up your plug gap and see if it changes.

I'll re gap and give it a test. Seeing as plenty other guys are boosting high.. It's not like they can't take it is it.

How much boost? Fuel type? What induction are you running (carb or efi?). How much spark at the boost level it pops, and what is the AF?

1.5
95 ron
12 idle
24 total
Water meth
No intercooler
40 dells
8.1 comp
12 afr

Your exhaust back pressure and valve springs maybe limiting producible boost. As your boost level and exhaust back pressure should be about the same.

If I remember right I've got duals on the lnlet and singles on the exhaust. I'll check

I really doubt it is the springs. I ran 30 psi on worn out singles.

I was more thinking valve float and pumping loss due to pressures in both sides. Though mine has seen 20 psi and hasn’t bought the farm.

Never know.

Hello. I got over a few issues a while back. Car does run 1 bar with an actuator rod turned a couple of turns, this make me have to pre load the actuator rod so it fits the turbo button fitment.
Not being an expert on actuators I've done this.
Removed the old actuator. This 1 wasn't too hard to work the rod by hand. The new 1 I've fit is more difficult to work by hand so I'm assuming I'm gunna get more boost without pre loading the rod. I want to achieve 1.5 bar with out a bleed valve.

Is there some reason you don't want a bleed valve? They are great. They let you hold the boost until the actual pressure is achieved. When i had my internal wastegate, it would start to open at 5-6 psi even though it had a 12 psi spring. Mine was instantly better installing the valve. It didn't really boost more (until i opened it up more) but it let it stay shut until i got the boost i wanted. No creep with the valve in place.

Well. Maybe I have a crappy bleed valve. I could only turn it a 1/4 turn from closed if that and it would boost to the moon. Maybe a better one with more adjustability will sway my thinking. I have also moved all the vac pipes to the hats, before I had them coming off the actuator pipe which confused the fuel reg etc.

I've just re fit the valve. Boost jumps over to 1.5 now. I'll have to fine tune it to just hit that number with a full foot full of throttle. Knocked the timing back some as well. It's hard to look at the boost gauge and the plx at the same time. Lol

Haha! Yep. I used to try to take videos with my phone while driving. Doesn't work!