Trinten's SBC/F23 build - The work has begun! (Page 69/69) Trinten APR 01, 11:49 AM Another productive weekend of tuning the engine and the transmission. The transmission tune has been a little challenging because of the torque converter and camshaft (for different reasons). Mike says because it's a little 'loose', that we need higher RPM to keep some of the chugging down (it would shift into third, then we'd feel this odd shake that Mike thought was the TCC locking up in error, it wasn't). Changing the shift points has alleviated most of those issues. Downside is 4th gear won't come on till about 65 (for now), and the TCC won't kick in till about 70. If we still get shuddering with the TCC, he'll just leave it turned off for now, until we can send in the torque converter to get it adjusted. This also means my MPG is going to suuuuuuuuck. Engine tuning for driveability is pretty much done. We gradually raised the RPM cutoff, and upped the boost a tiny bit (capped at 7psi right now). Startups are still an issue, but we noticed something odd when we were tuning for that. When starting it, I had to give it a little gas (RPM up to around 1800) for it to stay running. The FAST was reading 0-1% for the TPS! That's not right... Here's where it gets stranger, after about 30 seconds I slowly let up off the pedal... as I do, the TPS reading creeps up! No pedal, FAST things the TPS is at 2-3%. When driving it, TPS seems to read correctly!! So this is what I think right now. I know we replaced the IAC. I thought we had replaced the TPS as well once already because the original one wasn't sending a signal to FAST at all. So next weekend we're going to ohm out the TPS wires. If they're all good, I'll buy a FAST TPS to see if that solves that oddity. We also did some testing and tuning with the brake proportioning valve. After that was done, Mike did a brake launches in a deserted parking lot. He was surprised when the rear tires broke loose and did a burnout, given we have those z06 wheels and Nitto 555 tires on there, and all the weight sitting over the axles. So he's curious to see how tough it'll be to get it to hook and launch well at the track as we turn the boost up. I might have to get a set of slicks sooner than expected. He tried explaining to me that most of your 1/4 mile or 1/8 mile time is made in the first 60'. If you don't do well in that space, it's hard to make up for it. I also have a few videos I need to get off my phone so I can post them. This isn't the montage that Mike was working on, that isn't done yet. Just stuff I recorded while in the passenger seat. Trinten APR 07, 12:09 AM Another productive weekend! The new FAST TPS went on, we did the TPS learn sequence, and immediately saw some improvements with cold and warm starts. Hot starts are still a little twitchy, but it's much closer now. We noticed a behavior Mike called "trailer hitching" at certain RPMs when keeping an even speed. We then did more transmission tuning, and it's running much smoother now. We reconnected the wire for the torque converter lockup, and didn't feel the shuddering we had before, but we didn't get on the highway much today. We also turned up the boost a little more, we're around 8psi now. Mike is fairly happy with the brakes. He took the car out to an empty spot and tested heavy braking to see how the car would behave - he was worried about the rear end swinging around. He did have to do a little corrective steering, and said he wanted to look into options to increase the braking for the rear. So I'm going to look into brake caliper upgrades the Corvette guys run. Given that I have the S10 brake booster upgrade already, I hope those two things will work out well. And we have the adjustable proportioning valve if the new rear calipers are too much. We have work to do up front to push more air through the radiator. I have a tendency to think farther ahead and get caught up in my own concerns, so I had bounced my ideas off FieroGuru who pointed out some ideas. When I brought them up with Mike, turns out he hadn't overlooked it, just had it a little further down his list since the engine was staying at stable temps right now. I was thinking ahead to what would happen once we have the air-to-water running and A/C. For under the car Mike wants to setup a hinged plate with rubber sides, so if I bottom out on anything, it won't be as likely to get ripped off the car or permanently smashed upwards. The rubber sides will let it 'flap' on the hinge and settle back into it's proper spot. We also noticed the intake has some resonance, very similar to what my last intake was doing (the whoooshing sound goes away when Mike put his hand on it with a little pressure, same behavior that FieroGuru chased down on my SBC and solved with a clever internal mechanism). So I might see about attaching some kind of bushing to the underside of the decklid so it puts a little pressure on it. Will APR 22, 03:39 PM quote Originally posted by Trinten: -Replace the orifice tube and pull vacuum on the AC system to make sure it holds. Use a variable orifice valve instead of a fixed orifice tube. That will give better AC performance at low engine speeds and low vehicle speeds. Trinten APR 22, 09:26 PM Thanks Will. I remember reading about them before and being a little surprised at the price difference. I am about 80% sure that's what I bought. At least once. I say that because I've found like, 4 orifice tubes as I've cleaned up and organized things in my garage. I need to check the part numbers. This weekend we didn't get much done on my car thanks to the weather, Mike having an A/C issue for his house, and he was installing a motor into one of his other Grand National projects that needs to be done and ready to go within the next few weeks. He did finish what he calls the "hater pipe". The single outlet tube at the replaces the mufflers at the v-band. It's to remove exhaust restrictions for the track. You can definitely hear more of the cam-chop when that is on. I'm glad I have a few of the headlight control modules. I think mine died. Or the janky headlight switch in the beat-up instrument cluster we stuck in there for now died. CowsPatoot is going to be out there way in June before Carlisle, I asked if he would help with some of the stock Fiero stuff, since he knows a bunch of this stuff by heart. So I'll be asking him to help with stock internal wiring (like the headlight situation, the "power trunk release / emergency brake" safety feature (the donor was a manual), and working with Mike to get a few more gauges working (like the speedometer) before Carlisle if possible.