Which setup? EFR or GT3271? So far the SC is the weakest setup I've had. The SC hooks in 2nd gear. GT3271 spun 2nd in the midrange, but not up top on concrete. EFR was just silly but only had top end power since it was too big of a turbo.

The fastest my SC setup has been was not the Virtual dyno you saw. It was when I tuned for 12.8 AFR, ran 23 PSI, and threw 21-22 degrees of timing at it. I have a broken piston to show from that experiment though.....

Back on topic...

I'm thinking of running something like this:

Up to 20 PSI = 11.0
25 PSI = 10.5
30 PSI = 10.2ish

I don't know how much power I'd loose by running say 10.2 vs 11.0 though. But i really don't wanna break anything in this motor.

not a whole lot. (of power)
the det cushion should make it worth it tho

So you're saying going from 11.0 to 10.0 isn't gonna be more than say, a few percent? If so then I'll do that! Det cushion is what I want. Like I said, reliable first, power second. What I was worried about was going from 11.0 to 10.0 and dropping 15-20% power. If it's only say 5% then I'd do no question.

I have yet to see big power gains from running half a point and even a full point leaner.
At least not on anything I've touched yet. The biggest gains come from timing and boost



Also:

This seems to be my (limited) experience. So the goal for now is to max out the boost, and try to run as much timing as I safely can. So if more fuel = can safely run more timing, that likely is the recipe for most power safely.

So... Just ordered a 2.125" diameter pulley. So now, with a 1.6L SC, I will have a pulley ratio of 2.59:1. So with a 1.9L BP, motor will spin 2 turns and breath 1.9L of air, SC will try to push in 2.59 (SC revs/crank revs) x 2 (2 motor revs/cycle) x 1.6L = 8.28L of air...... My excel sheet shows this will result in 71 lb/min of air if the SC can maintain 90% volumetric efficiency at 7,700 RPMs. All the boost.

:)

Next post like this and it gets the hose

Haha, good price range is buy 2 name brand turbo kits instead, it's cheaper and probably faster too.

700hp?

No way.

But north of 300? Possible. ;)

71lb/min is damn close to 700 hp. Something is isn't adding up.

The SC is rated for that flowrate, I don't think I'm going to get it though. Also you're thinking of turbo-world lb/min to whp conversions. This blower will be sucking over 100HP from the crankshaft to deliver 30 PSI boost.

My goal with this setup from the beginning was 350whp with reliability. That's still more or less the goal. If it makes more than that, AWESOME, but 350whp was the goal and it still is. My gut feeling says if I can keep AITs down (working on this part) and get some more timing in it, with 30 PSI is should make 400whp on 93 Octane. Sure it would make more with E85, but this is a street car and I want it to run on pump gas, and do so safely. When MS3 works flawlessly with the E85 sensor, I'll jump on that bandwagon.

Theres a lot to consider here ... Granted, all my tuning is in turbos, im sure at least some of it rolls over to SC.

1. Too rich can lead to cylinder wall washing, which can cause cylinder damage as the fuel basically removes the oil coating on the cylinder. That being said, high 10s shouldnt be enough to cause a problem, just be aware of it.

2. With a fixed boost source, really your only means of combating knock will be to retard timing, and high boost + low timing will easily cook an exhaust valve. That and hot exhaust valves can be a hot spot that causes detonation anyways.

3. Another thing that may get tricky, is advancing the intake cam at higher rpm, while increasing dynamic compression, will also choke airflow. Could be a viable means of controlling power, but really at that point its a band aid.

4. Shit, i could go on and on but its more hardware at that point than the actual tune, so ill stop there. Again, my experience is in Turbos - tuned quite a few mazdaspeed3s, and they run pig rich from the factory too stock, around 10.8 to 10.9.

Methanol an option?


Also, what part of Houston are you in? My fiance and i are getting our NB2 ready to start hitting tracks in the fall, no point in trying to do anything during the summer.

1- I'm aware of it. From what I've read I should be fine. I don't think I've ever actually seen a motor where the cylinders suffered wear from high AFRs in boost.

2- I do have inconel exhaust valves. Yeah fuel and timing are about my only means to control detonation.

3- I don't want to restrict flow/hp to limit det. I want all the flow, all the hp!

4- Thanks for the datapoint! Looks like high 10's is common in boost OEM motors.

Methanol- For now it's pump gas only. Based on what I'm able to do on pump gas, I'll go from there. I'd prefer to not run water or water/meth, I'd probably try to flex-fuel it first.

Either way it sounds like I need this thing in the high 10's minimum on fueling at high boost.

As an update/follow up to this thread...

I tried tuning the car to 10.2 AFRs in boost at 28 PSI. I couldn't run more than 8* timing advance without it detonating. If I ran the motor when it was warming up (CLTs at 170 and rising from a cold soak) I could run 12* without knock, but as soon as it got up to normal temps at 180 for 10 minutes or so, it would knock at 10* but not at 8*.

I switched the car to E85... Also changing the intercooler setup to try and lower air temps. I think with cooler air and E85 I won't have any detonation moving forward.

You shouldn't. It takes a lot to knock on e85
And your targets should be 11.8-12.2 now

I'm hoping you're right! I want this detonation to be gone so I can throw some timing at it and make some power. With 28 PSI and E85, it should be more than 200whp I'm thinking.

Question: Internet says Max power rich E85 AFR is 0.71 Lambda, which in Gasoline AFRs is 10.5. Have you ever tuned an E85 motor that rich? I don't know crap about E85 tuning yet to be honest....

I've hit those numbers before while tuning, but do I intentionally run that rich? Nope.
Even the guys making 500-600 don't run corn that rich

I'm going to guess that in practice, there is no actual "gain" in power running that rich? Or is there some other reason?

Man I'm excited to get this thing back together and tune it! :)

You run pump gas rich to have a det cushion.
There is no need for this with corn.