I am going to try to work through the theoretical mixture ratio for you, could be a clusterfuck so don't take it as gospel.

Water has an octane that is infinite, therefore you cannot calculate for it and it can be dropped from the equations.

I will assume you want to run Lambda 0.84, could be whatever you want.

E10 stoic is 14.1, so 0.84 gets you 11.84
Methanol stoic is 6.0 = 5.04
Assuming your peak fuel load is 16% methanol:
84% @ 11.84
16% @ 5.04

(16*5.04+84*11.84)/100 =10.75 this means 0.84 lambda for the mix is 10.75. You could probably survive running leaner due to the methanols resistance to detonation, but running it this rich gives you some protection if the meth were to run dry or have some sort of failure and should make close to best power.

What I don't like about this calculation is the meth load is changing, even if your system is progressive. If your on a single stage kit and your coming in at 3k rpm and running to 6k your peak meth % is roughly doubled at low RPM.

 

I'm not sure meth injection is ever needed. Could be very desirable though, significant charge and chamber cooling. I run a WM kit at 30% methanol on my whipple mustang just for the additional rotor cooling and cleaning effects, no added timing but still a slight increase in power from charge density.

 

Well this got exciting!

I acknowledged my failure in terms of removing fuel (or more accurately ignoring the change in average AFR) however at my injection percentages I think some reduction is necessary. I may be wrong here but my thinking is that I'm adding enough methanol (+7%-ish pump gas equivalent increase) that some pump gas should be removed. I'll look at this more closely to see what would happen if i'm on the reduced fueling table and the kit quit working.

I've considered something more elaborate to interlock the meth/water system to make sure it's working (I.E. mac valve only functions if meth pressure > X psi). At the end of the day its a simple enough system that I'm not worried about it. I have an IAT gauge so I wouldn't see the temperature drop I am seeing now (even if it's artificial due to evaporative cooling on sensor). As a safety measure I can pull timing as a function of IAT so a little bit of a safety there and that's zero cost to implement.

Sadly my time is toddler limited so while the nerd in me would like to datalog every pressure and temperature and make this a big experiment, I'm going to keep running it and turning it up until I let the magic smoke out. $275 complete 4.8 so I'm not worried

 

I can blowup 4 5.3's for the price of the 383 I had. LOL

 

I'm not stopping at 11 psi, but no probably still not needed. I was just trying to keep a safety margin since my tuner is questionable at best...

I agree on all parts. I am on a single stage and it's coming on at 4psi so yes 3000-3500 rpm give or take. If it's a little methanol rich at the lower end but it RPMs through it maybe it wont matter.

I could try to interpolate the target AFR map and VE tables but again how far should I go with it.

The problem I see is coming up with that 16% number and how accurate it really is. I dont know fuel pressure or methanol injection pressure with any real certainty, and that can skew both flow rates greatly. I can post of how I got to that number, will try to do that this evening.

 

I have the new rear end almost fully installed. 8.5" 10 bolt out of a 1971 Buick which is pretty awesome for a bunch of reasons. Also 3.90 gears and a used Trans Am posi carrier.

I also hooked up the MAC valve and will attempt to run this off the micro squirt. Will readdress the fueling stuff when I get it moving again. May be time to just start a build thread...

 

Ran it at the track 8/12 with similar results. Seems I was able to footbrake the previous gears more, so in the end it was a wash.

At 10lbs it was almost no change, 13.3 @ 106 with a horrible 60ft. Cranked boost controller up to 18lbs and it ran 12.86 @ 108.8mph. same shitty 60ft (2.2x).

I haven't made it through the logs yet to see but the mph not really changing has me concerned. Is the motor making power and I'm losing it through the th400/converter or is it not making what it should be.

Best run of night before getting towed home...



I'll try to review the logs tonight and update this.

 

Towed home? Sorry to hear that!

 

Yup, my shifter bent/distorted enough I shifted past third and into neutral at 6800 rpm. I had a pressure gauge on the th400 and it's rubber line blew. Not sure what I hurt yet, if anything.

 

Check your converter slippage, that should tell you something.

 

9.5-10% slip on the two clean runs, 11 and 17 psi. Numbers based on GPS data that agreed with trap speed.

The shifts are dropping about 1200rpm and taking 0.5 seconds (1-2 shift) and 0.25 seconds (2-3 shift) according to the datalog. In the car it feels sluggish like the shifts are very lazy. I'm thinking about tearing down the th400 and just seeing what I find. Maybe learn something. I am running the Transgo full manual kit and the pressures were good but I still don't think it was what it should be.

I don't know enough about converters to say what slip % is good. Suggestions?

 

In the original vid the car rolled a long way before getting into boost. I assume the same thing is happening in the other vids.

 

10% isn't horrible, but a good converter could be about half of that. It's not the cause of your lack of mph imo though. A .5 second shift is slow.

 

Pretty much yes. I need to figure out how to launch this thing. Planning to start playing with the 2 step once it's back together.

That's what I'm finding after looking at other logs I could find with similar powered cars with TH400's (slow shifts). It's decided, I'm tearing it apart.

 

A transbrake is definitely on the to do list.

 

My guess is it ain't making power. 108 on 18 psi? If the trans was eating power it would probably be smoked by now.

Our blow thru sbe 302 with stock heads and super mild cam was trapping 108+ on 8 psi.

 

Im no LS guy , but 16 degrees of timing on 12 psi ?

Do you guys really have to run so little ?

My sbc is at 24 degrees on the same boost on 93 pump gas .

 

Hmmm well shit. I have to start somewhere so trans and converter then see after that?

I'm in agreement but don't know where to continue looking. I checked everything I could think of, may just throw some timing in it and see if it goes boom.

I'm only doing what smarter people before me have done. Something about more efficient combustion chambers require less advance to make power.

 

15/15 is pretty common on these with pump gas. I agree that its down on power. You verified timing with a tdc stop, and light? Was the cam degreed?