565/524 hx-40

[MindBlowin03]

Aha! Then you really are running quite a large amount of meth/water, as you said back in 2010, when you figured it was about 1000cc/min.

I am running a large amount of wmi yes but I didn't install it to combat knock at that time. When running 20psi/15* timing the car did not knock at all. I seen AFRs anywhere from 10.7 in one log to 12.4 in another log, without ever knocking. I was consistently seeing ~44 lbs/min as well.

Ok here's the next thing. I've been looking at this huge peak in power/torque that we see (I see) between about 4800 and 6200 rpm. Cyclone manifold, I know. But I'm thinking maybe there is also a pretty big boost spike there too.

Yes, there was a boost spike for sure. It's hard to really tell for sure because the MAP sensor only read to about 38.6psi. Boost spikes past that right near 4900 and then tapers back at about 6800 and stays.

Here's what I see when I look at the picture from your Link log. I'm looking for boost, because I want to see if your log knows what the boost was at all times during the pull. I see a GM 3.3 bar MAP. It says 38.6 psi at the current spot, but the bright silver curve for it is totally flat-lined through that whole region that I'm looking at. So the MAP is apparently totally maxed out and reading flat as a gage table. Then the fainter silver/gray line which is Link BoostEst peaks way the heck up higher in that region, but follows the MAP curve everywhere else. So I'm thinking you may be doing well over 40 psi for a while in that region. BoostEst is still going up like a rocket at the point where the MAP signal hits its ceiling. What do you think about that?

Again, there is definitely a spike but hard to tell exactly how much. Was it over 40psi? I would say definitely, but it's not very accurate after 5500 or so which makes it hard to tell exactly.

I also wonder if a GM 3.3 bar MAP can even read to 38.6 psi, because 3.3 bar absolute would be about 33.4 psi of boost. Maybe it can go "off scale" a few psi.

I know your math is correct but Im still not sure on that. I had a GM 3 bar that read much higher than what it was supposed to. I always assumed they read higher than advertised.

Anyway, I know that up in post #1 it says 38 psi, but do you have any idea what the boost actually gets up to in that area around 5500 rpm?

No, but I will take a stab and say under 45psi at it's peak. Being that my max HP was from 6300-7200 I never really bothered to care much about the spike since it didn't give me a 'false' reading.

 

[We're on Boost]

Good deal, that all really clears some things up for me.

I don't know enough about Link to know if the BoostEst would be reasonably accurate in that peak region, or if it gets thrown off by something.
But like you say, you are running on a GM MAF, not the MAP, so it doesn't really hurt anything that the MAP is going off scale. It's "read only". And since the wmi is triggered on by boost at a lot lower level, you are getting full wmi flow there even though airflow and MAFRaw are not topped out yet. I would say that is a good thing, because otherwise it could be boom city when you hit that boost peak. That is a good point for me to remember because I'm probably going to use a 2D wmi map based on boost and MAF Hz. But now I will be sure to map that thing so that wmi flow is max above some certain boost, no matter what the MAF Hz is, to accomodate any unexpected boost spikes!

Which brings up - did you get that boost spike in there on purpose, or on accident? I don't see your wastegate or boost controller listed. What are they?

If you still have a log like that lying around, could you take a look to see what the BoostEst is at the peak? The 43.5 number is quite a ways to the right of the peak.

 

[MindBlowin03]

The spike was on accident. Peak spike via BoostEst was 48.8psi. If I run in the 35psi range or under(which is 99% of the time) the car only spikes a bit then settles quickly. Anything over that and I need to crank the MBC down and it causes bigger spikes.

Just updated my mod list to include the Tial 38mm external wastegate and JoeP. inline MBC.

 

[We're on Boost]

Super! That really clears some things up, again.

Do you think the Tial 38mm is just not big enough when things get really cookin in there? Anyway, some folks would go an extra mile with controllers to get a mid-range peak in there on purpose. But it's gotta be safe for the engine of course.

 

[MindBlowin03]

Well, I always read(but no personal experience) to keep with a 38mm wastegate with higher boost as it will want to 'push' open a bigger wastegate since there is more surface area trying to keep closed.

I love the slight spike that I get on a daily basis. The dyno was an extreme case. Most of the time Im setup for about 32-34psi with minimal spikes, and it's perfect.

 

[We're on Boost]

That's what you want: Perfect