Yay for speed density.

Want to borrow my LM1 for wideband testing?

Frank, from my looking at the 3.8L GM (same manufacturer) blower, I was thinking that you could add that into the MS equasion. With the extra outputs of the MS relay board, maybe actually controlling boost with the bypass valve for load conditions.
EG:Uphill grade of 5% load detected by RPM's & MAP sensor = "Somuchboostpressuredesired" controlled by a PWM air bleed solenoid (converted GM IAC) to allow butterfly partial deployment. Say needed boost was 2.5 LBS, butterfly would close a specific ammount to allow that much boost & then control the diaphragm through the IAC setup.... It was how GM used the setup, if I remember correctly.

Just to let you know, if you take a 95 Bonneville, it uses the same ECU part number wether it's supercharged, or not. The difference is that the SC car has a different MAP sensor mounted on the firewall & wiring harness.

I wonder if anyone has decoded the GM ECU to assist in your tuning?

Ed

Curtis - Thanks for the offer.... maybe so. So far, my plan is to buy an LM-1 for permanent installation so I can also use it for data logging and dash gauge readout, but I haven't decided for certain. I know I don't need it beyond the tuning stage, but it seems to me that a permanent installation is a good idea.



Ed - the bypass valve vacuum actuator works in a similar fashion - as load increases, vacuum drops and opens the butterfly valve in the blower. It's a gradual blend of air to the blower - not like a switch. From my earlier driving impressions pre-failure, the vacuum actuation works great and blends very smoothly. If you didn't have a boost gauge, you'd never know what was happening.... except for the sound at WOT....... <img src="/forums/images/graemlins/smile.gif" alt="" />



Engines have their individual quirks with ignition timing needs, so I'd rather give this one what it wants to be happy. I don't have the factory timing map for it, but I did find the map for a 24v DOHC TT engine. It's quite different from what I observed on the SOHC Montero engine. Peak advance is similar, but the VR4 curve is stretched out over 8500 rpms instead of 6500 rpms. Where the VR4 has 34* of advance @ 3000 rpms/light load, the SOHC trucks have 40*.

Here's the ignition map for a 1995 3000GT VR4:

Ignition Map

I would not want to install MegaSquirt on a 24v engine - looks like a nightmare in Alpha territory.

Frank

Get the LC1, and remote display then <img src="/forums/images/graemlins/wink.gif" alt="" />

If you mean the MegaViewer display that scrolls the ticker tape across the dash, I don't want it. I'm thinking about installing a wideband AFR gauge on the dash for readout in addition to the laptop display (which I won't use much beyond final tuning).... don't know that I really need it as a permanent installation, though.

Frank

Hi Frank
I have four Megasquirts at this time, The early 4G63 can be a bit bitchy to get the ignition right on. Working with the dizzy in your truck should not be an issue. Plus you can run the basic MS2 so there are no issues with rising or falling edge triggers as with MS1.
The DOHC engines have much better combustion chambers therefore needing less spark lead, or timing if you call it that.
I have thrown away two LC-1, they are very restrictive in there setup and quite fragile electronically.
Take a look at these from Techedge, Tech Edge 2J1
Much better units to work with, more for the money and they do not emit smoke like the not very inovative stuff. Great company too, responsive and quick shipping.

Hi Charlie,

I'm glad to hear there are some other MS users here. Curtis has done some, but I think on SBC engines.

One reason I elected to keep the 12v heads is because I thought MS might be in the future and it seemed easier to learn MS with the optical trigger distributor setup.

Thanks for the TechEdge info - I briefly looked it over and realized that I've got a lot of learning to do before I make a decision on the o2 sensor and controller choices. My original idea was to install the LC-1 with an analog dash gauge (for monitoring while driving) and use the laptop for tuning. I'm not yet sure if that's possible. I've heard some noise about the LC-1 being a bit sensitive and leaking smoke <img src="/forums/images/graemlins/lol.gif" alt="" />, so I'll do some serious reading on the TechEdge.

Thanks,
Frank

Please tell me those relays aren't they way they pmw the injectors <img src="/forums/images/graemlins/scared.gif" alt="" />

no man. Thats all solid state.

Im guessing Fuel pump, electric fan, and aux.

<img src="/forums/images/graemlins/lol.gif" alt="" />

The relay board only has value when converting a carby to injection. I have two of then sitting here but have used doner harnesses for conversions for the ease of having more oem connections rather than shop connections, Time and reliability.

When converting an already injected engine, use the harness that came with it. If you can get another harness you can convert it to the MS and then swap it in. This is one way to provide backwards compatibility.
I did pull a connector out of a Mitsu ECU and make an adapter harness to plug the MS into a stock harness. This was nice since the 4G63 seems to act different for some people as far as getting falling edge from the optical sensor. MS1x really needs that.

I think every one that put a LC-1 on a MS got smoke, this was due to a diode in the O2 input that flashed the LC-1. Then I had one die free standing feeding my laptop. Junk they are.

The Tech Edge are robust, all the bells and whistle you will need. If they had the new mini sized one out years age I would not have learned how bad the Innovative products are. I had needed a wideband on a turbo BMW bike.

All my injections run Wideband with full closed loop operation. The dash display is nice but do not tune by it. Theh Edge has an assortment of display types.
With the wideband run into your MS is will be on screen and once you configure the auto tune it will rough in your fuel map for you. From then it will always be there.

Drats big thunderstorm coming, I need to shut down. I will be back.