Thread: How to know safe boost on pump gas?

blow it up and turn down the boost next time

gomba you are understanding it correctly.

According to Garrett's site, using their '2.0L' example numbers, it appears on my compressor map from all the calculations that it falls almost right in the middle of the compressor map for 16psi. 18psi is still in the middle efficiency island but at the edge. Looks like even 20psi would still plot in the middle, but a little further up.

Soooo, if Garrett's numbers are close to what the DET produces and from the other information given here, I could run about 16-17psi daily and be perfectly safe and within the large efficiency range of the turbo? It seems 18psi is still within the middle efficiency island. At 22psi, it would probably still be pretty close to the middle, but getting to the edge of turbo speed.



I have no clue if the numbers are close to what the DET produces...

Anyone have the numbers for calculating compressor maps for the DET? Ben?

Unearthed the motherload of SR20 compressor map info!

NissanPerformanceMag.com

This is my fav calculator
Squirrel Performance

My experiences with detonation start out with the first signs being the plugs. I noticed after some 19-20psi pump gas runs that my plugs would start to misfire. After pulling them out I found that the ground strap had been closed. Ive seen this on many cars now and it seems to be damage from strong detonation. I've seen gaps close, the ceramic break, and the ground strap melt. I actually have a motor here that cracked some ceramics (but didn't swallow them) and the pistons look perfect surprisingly.

Once you see the ground strap start to melt, expect the same from your pistons.

Detonation isn't just an engine killer, pieces of plugs and pistons can come out of the exhaust and damage the turbine as well. I would read the plugs after a hard pull and shut the engine off immediately after passing peak torque. If you peak at 4000rpm, shut it down at 5000rpm and then check the plugs. The Ceramic part won't collect dust, only metal can stick to it. So if you are getting very small spots on the ceramic, you should back it off a bit and check again.

Or you could just buy a knock light and monitor knock yourself. They work, and they save motors.

I always forget reading the plugs (since I'm not great at it). This method can be used as well. However keep in mind you'll want to shut down the engine immediately after the moment you want to check and see if there is detonation. Running the engine for a bit after the period of detonation will hide the signs of detonation on the plug.

Edit: I see you mentioned that already.

i have melted a ring land and the plug looked fine. I would like to build the electric stethascope and listen to the motor next time i tune. I hear this is the best way. Just gotta learn what to listen to. Wish i could just go hang out a dyno shop for a week and learn stuff but i dont have that kinda time any more

what do you do/use to avoid knock?

I read plugs, and run conservatively. right now I am running 15psi on pump 91. But I am also at high altitude. Total pressure and air density is like running 12psi at sea level. I feel this is a safe level. But I have used a knock light before and I think I am going to buy another one.

Wow and you run a 3076? 12psi would seem a little low,eh?