As to the clutch robbing power, it's possible if it's a lot heavier. Much like heavier wheels/tires will change dyno numbers. I wouldn't think it would change it that much though. I'll be able to tell you when I install my RXT and steel flywheel.

Edit: Just saw you went with an aluminum flywheel. You shouldn't have lost power with that setup.

 

I don't know the answer to any of these questions. I've got a very reputable tuner and I feel sure he make the right settings.

 

Have you talked with your tuner about your concerns yet?

 

Of course. I was there when he tuned it. He was surprised that it lost power as well. It's probably just normal variation, but I was really hoping to dyno at least 700 RWHP.

 

Unless you were pulling timing for high IAT before adding meth it may actually dyno lower due to running richer. For the same amount of total timing. Plus you lost about 10rwhp from that .7psi drop. That being said the meth should show more mid range torque.

 

Probably some truth to what you are saying about the actual IAT reading and what it actually is. I bet Juilo could answer most of the questions.

 

Several people don't realize that you can't pull enough timing at big power levels as too little timing also causes motor failures.

I see guys on 18-20psi thinking all is good running 91 octane and meth. I think they're playing with fire.

 

Anyone running that much boost is on a built motor, so at that point it really becomes a question of how well it was built and how it was tuned.
20PSI sounds terrifying on a motor that was never intended to see any boost in the first place, but on dedicated FI platforms you can get it stock, under warranty. That is about the factory boost level for an AMG Mercedes 4 cylinder, a 4 cylinder mitsubishi turbo, the new BMW M3/M4, etc...

 

Of all the people on here who should know better than to post that apples to oranges comparison... You would be the last I expect to do it.

20psi in a 400+ CI motor != 20psi in a little bitty 4cyl. Since psi actually stands for something involving in^2 and the larger has more of those, it's more pressure and volume.

I have a big cube, built motor. I can't run 20#s on 91 octane period. It's not possible. To little timing and I cook it, just enough timing to run it will be knock in the upper RPMs. You should know this Mr. Labs.

 

I'm going to have to guess that he left the timing the same. I dialed in my IAT/spark table to add extra timing when the IATs drop from the meth spray. If there was extra timing added, then I'm baffled on the results.

To the OP... meth isn't "needed" at your power level -- your tuner is right in that respect. Is it a good thing? Yes. Octane is the big limiter if you're trying to make more power or boost than a base blower kit provides. You can only run so much boost and timing on regular pump gas. That is a fact.

 

I think his point was, "on a dedicated FI platform" , in other words, an engine built for high boost, 20psi even on an LsX engine is possible, and sustainable.

Like you said, you obviously cant compare this to a lityle 4cylinder evo running 20lbs.....

 

The timing must have not been touched. Otherwise I see no logical explanation. Your rwhp loss like jon6.0 said is coming from the .7psi you lost, which could come from warmer weather. Other than that, not sure what to say.The meth definetly didnt cause the drop...

 

I get along without meth just fine but there is two things,
I live in western Oregon so the temperate climate is better for boosting.
Then I have a safe tune with 12 degree's max timing but it's plenty
for me. The 427 loves the boost and has plenty of tq!
625 rwhp or whatever it is at a certain time is plenty in the Z06.
Not seeing where 800 is needed!

 

Its not more pressure, it is the same pressure. And the volume is irrelevant, but I know what you are trying to say: PSI is a measure of force per area and with a larger area you have more force on the big cube motor. True, but the bore of a Porsche 911 engine is virtually identical (6mm smaller) than that of an LS motor and they run 18PSI from the factory, so again that reinforces my point. The larger cylinder diameter would in theory imply that there is a higher connecting rod and bearing load than a small engine, but the reality is that the LS engine's archaic 2-valve per cylinder head design really limits how much air you actually get inside the cylinder, so the resulting total charge air mass is LOWER than a state of the art 4 valve head at the same boost number. I.E. The cylinder pressures on a boosted LS engine will be lower than cylinder pressures on a comparable engine using a 4-valve head (most other engines).

If you are knocking then you have too high of a compression ratio for your fuel octane. If your objective WAS to run 20 pounds of boost on 91 octane you could simply lower compression by a bit. Yes there are many reasons why you may not want to do that (throttle response, fuel economy, etc), but that is the solution... Back in the turbo days of Formula 1 they were running 40+ pounds of boost and engines were maybe 8:1 compression to allow that to happen.

 

20 psi here on a stock LS1 with 93 octane and meth. The physical components of an engine don't concern themselves with whether the power is being developed from forced induction or atmospheric. In the end, the forces must not be greater than the strength properties of the material, including it's fatigue life.

Take a piston and set it on the work bench and direct a stream of 200 psi air at it, no change. Take that same piston and hit it with a sledgehammer as hard as you can and see if it is worth reusing.

 

I'm interested in hearing more on too little timing. I am not saying it is wrong, but what is too little, and what happens? My friend here tunes a lot of imports, evos, stis, etc. They command zero degrees of advance on a lot of cars that are running 40+psi of boost on 2-2.5L motors, making 600-850awhp. They don't melt, don't take out valves. As the RPM increases the time for combustion to take place gets smaller and smaller. So spinning a 2.0L to 8500rpm he said you get to the point where zero timing is the correct amount. That is on crappy stock mitsu valves which aren't nice SS or Inconel valves like a lot of FI motors use.

Even if you had 5-6 degrees of timing in an LS, what goes out? You cook a valve? Who has actually burnt a valve on an LS motor from too little timing on high boost?

I personally don't like going below 10 degrees but just wanted to see what others though.

 

Timing advance is related to how fast the flame front travels. You want to get a complete burn at the right time to maximize power. If you ignite the mixture too late, it will still be burning when the exhaust valve opens and the temperature of the gases is much higher. Not to mention some of the power that you are giving up by waiting too late to intitiate the spark.

 

I get that, but what is too little. If the flame front/burn gets quicker as power goes up/boost/rpm/etc and timing goes down, then without messing with EGT testing/etc how does anyone know what too little timing is?

And wouldn't cam timing have a huge effect on it. If you are running a 230 degree exhaust lobe compared to a 260 you have a lot more seat time for the valve to cool, or a lot less time that valve is held open. I'm sure cam timing and dynamic compression has to play a big roll in boost/etc. Without dropping compression someone could do a cam change and have the car take more timing or less just because of the cam specs.

 

So I read the same post a while ago... but I got meth anyways.. and I don't get it... How do you have your meth set up that you could run out an entire washer fluid container of it on a road trip? Mine triggers at above 5psi..... single nozzle. I have done multiple 1/2 mile drags at pocono all day and never filled it again for maybe another month of daily driving.... I activate the meth pretty much every time i drive the car at least for a bit and still don't run out so soon

Is yours active all the time? I can't even imagine driving it like you stole it THAT much that you have to worry on a longer trip... are you tuned for meth dependency ?

 

I've gone through 2 gallons in a month. 15gph single nozzle. I do drive it like I stole it, lol.