for street purposes...off-boost performance is important to most people. The beauty of our motor is the deep torque curve,,,,even at very low RPM.

I dont want a gutless motor below 3000rpm. I think 9:0-9.5 would be my ideal.


350zteve, I agree with you for the most part...that forged internals wont save you from detonation. However, LC pistons will resist detonation, and if detonation does occur, they will hold up much better. Forged pistons tend to have better rings, pins, and of course we change the rods, so the entire rotating assumblying is significantly strengthened.

Also, I dont want people to think that 1 sec of detonation will blow up a motor. Detonation, or pinging, occurs on the power stroke, AFTER the spark has fired. Engine can tolerate a good amount of pinging for many many minutes. I have a company car (Pontiac Grand Prix 2002), and the thing pings like crazy when I floor it up the onramps. I kinda also do it for fun...since its not my engine. My point is that lots of cars detonate or ping, and it doesnt result in the immediate destruction of the engine.

The real danger...and most people don't realize this...is not detonation, but pre-ignition. Pre-ignition occurs on the compression stroke, BEFORE the piston reaches TDC, and BEFORE the spark fires. So essentially, the fuel/air mixture is spontaneously combusting while the piston is still traveling upward. Run that image through your head...and you can see that the piston is traveling upward at TREMENDOUS velocity, and then boom....the piston is hit with a force that is trying to drive it down. The result is usually immediate and catstrophic failure of the piston, rings, rods, or rod bears. This is ugly.

Pre-iginition can destroy a motor in 1 sec...no joke.....but detonation or pinging takes some time. Of course, the wild-card here is that detonation can eventually result in pre-ignition.

So the moral of the story is.....when you hear a ping....let off the gas immediatly.

Did everyone enjoy the bedtime story?

Sweet dreams everyone!

 

If you use a TT kit with stock compression and then rebuild the engine with lower compression, the car would lose its zippy torquey feeling when off boost cruising. Of course that's the trade with TT vs. N/A but i don't believe everybody is after power on boost and doesn't care what happens off boost. At the end of the day most ppl who opt for TT are after porsche 911 twin turbolike performance+ for less half the price.

I'm not sure if greddy or PE release information on what comp ratio is the best to use with their kit. But that'd be great to know. Ppl who buy Greddy, PE or APS tt kit will rebuild their engines sooner or later so it'd be good to know what CR is the best for each kit.

 

if the turbos are sized properly for the engine, then you should be well into the spool by 3000 rpm....so the engine would feel far from gutless

 

Z1, a lot of people, inlcuding myself, whan to maintain significant torque below 3000rpm. In my opinion, the car on the street...especially on surface streets is rolling between 2300-3000rpm, so I would like to maintain that zippy feeling down low.


Hey...so WTF...nobody liked my bedtime story?? I endured hotel dial-up to write that thing up.

 

Yo gq, yeah your story was mad l33t.

Anyway, do you get boost under 3k ? I don't think I do...

 

Yes, you should be getting significant boost below 3K...especially in the higher gears. If not, the tapper gasket thingys were not installed on your wastgate. same thing happened to a couple other people. I can hit 6psi of boost at 2700rpm in 5th gear.

Another possibility is a boost leak somewhere.

 

No, I do get boost in the higher gears... no gauges yet so can't tell how much, but I can hear violet wastegate noises under 3k if i shift 4th to 5th gear...

But like in 1st and somewhat in 2nd, it kicks in around 3k+, that normal ?

 

Hey Slay2K, I would recommend you get a boost guage so that you can see what your boost is at. Also have you dyno'd to see if your a/f is in line? Just somthing to think about. Sorry if you already done this I haven't kept up much with the FI section.

 

Hey 350Now, Defi's are on the way... I'll be dynoing the car soon.

 

Yeah, at lower RPM, in 5th gear, it kinda feels like there isnt much boost, but the boost is there.

Cant wait to see your dyno results. Have fun!

 

Thanks slay2k. Post dyno when you are done, would be interested in seeing what you get (RWHP, TQ, and A/F). Fun times to be had..