Jcamper's 1985 SVO

[Jcamper]

Have my 1985 SVO back on the road doing daily driver status (100 miles a day) after a bit of a hiatus. Over the summer I swapped the turbo for an HX-35 I had on the shelf off my pickup, added a front mount intercooler, Aeromotive fuel pump, went one size up on the fuel lines, and installed two fuel filters in parallel. Running a transducer for fuel pressure at the engine and before the filters in order to monitor filter issues and overall pressure. I installed a flex fuel sensor, a new Megasquirt 3 system with LS2 truck coils and 120 lb injectors. Used my old distributor as a cam sensor (cut three of the vanes out of it) and added a crank position sensor so I could run full sequential fuel and spark. I am using a bosch broadband knock sensor bolted to the block that is feeding information to the new internal knock module in the MS3 system. It is programmable for all parameters including gain for individual cylinders, multiple frequencies, and knock window. I have boost control in the megasquirt but am currently using the stock cummins wastegate. Seems to work fine, I get about 25psi currently.

A "rally style" anti-lag system has been implemented to eliminate turbo lag during autocrossing. This included two 1" solenoid valves which allow air to bypass the throttle body when the throttle is closed. Should be fun I think.

I am tuning it on E85 right now, will switch to normal gasoline after I am done, then blend based on the flex fuel sensor output (MS3 allows this).

Issues have been:


Flex fuel sensor isn't working correctly, I will have to get a new one- scoped it and it is out of range.
Idle is a bit sketchy, had to idle it up a bit.
It is cold out, has trouble getting very warm (could be the E85).
Need to add a couple inputs for the transducers, they haven't been implemented yet.
Need to figure out how to make the stock tach work. Shouldn't be too difficult.
Cold start and warmup is interesting getting correct


Overall it drives well, runs well, and I haven't played too much but it doesn't seem too laggy, I guess I was expecting worse. It is significantly quicker than it was though.

3121

Jeff

[Jcamper]

Figured out the idle issue; I had inadvertantly enabled "roving idle". I guess I know it works now. So with that hurdle the car runs/drives like stock other than cold start (and of course under boost).
I know that at some point I will need to replace the rear end and clutch. Jeff

[Chalky]

Can't wait to go for a spin mate!!! Now, you are gonna make it to some shows this year right???? :):):)

[Meotchh]

He better at least show up for Bellevue!

[Jcamper]

No promises, but I will try to get out. Generally if I am going to have some time to burn doing car stuff, I will use it autocrossing. I would like to say I would use it on track days but those are more bucks. I am hoping to get some kind of internship for the summer, have no idea what that would be yet, so that will kind of dictate my schedule likely. Plus my car is ugly. Chalky mentioned that he likes to keep electrical tape under the dash, not on the steering wheel. I told him he needs to expand his horizons, be open to new things. :D

The interior of my car is like an anti-theft device in and of itself. Ripped seat, missing knobs, faded plastic, the whole deal. Jeff

[Chalky]

I might have a wheel for you, we'll talk:):):)

[Jcamper]

You are the owner of quite a few spare parts right now, aren't you? I have a small collection. That was mean, wasn't it? I ban myself for that.

[Bob Holmes]

And...what evidence do you have that the anti-lag system improves your performance? I'm very interested, I'll implement anything that will help me beat Vrinner.

[Bob Holmes]

You are the owner of quite a few spare parts right now, aren't you? I have a small collection. That was mean, wasn't it? I ban myself for that.

Ouch, a self-banning was in order. Good show.

[Jcamper]

And...what evidence do you have that the anti-lag system improves your performance? I'm very interested, I'll implement anything that will help me beat Vrinner.

It should effectively help keep the turbo spooled. Downsides are it is tough on exhaust valves, turbine wheels, and exhaust systems. However, much of that comes from the implementations that rally competitors used; extreme boost off throttle, using it for long periods of time, etc.

Bypassing lots of air and being less extreme with timing retard combined with short stints will hopefully make it less damaging. Rally rules said you could not have extra solenoids for bypassing air. They would generally jack open the throttle, and use a fuel cut for idle so the engine didn't rev to the moon (known as rotational idle). This also has the side benefit of quickly cooling off an engine since ALS (anti-lag system) tends to result in extreme EGTs.

I have never seen anyone do this effectively for autocross, most use the IAC as their only bypass, and it doesn't flow enough air for effective antilag.

It works by retarding spark way back (there is a table so you can make it transition from normal throttle more smoothly), this makes the engine not produce any torque. It is also injecting extra fuel, so you get backfires in the exhaust manifold, combined with lots of airflow keeping the turbo spooled.

You will lose power brakes due to no vacuum ( I am thinking about using frame rails as increased vacuum storage).

Having written that essay, it will only help my (or your) time as much as having some increased power at lower rpm will. I would guess to maximize the return in our cars you would need race tires, strong rear end with a good limited slip, TA/PHB or the like.

It should be good loud fun. Jeff

[Jcamper]

Soldered in the other two inputs for my fuel pressure transducers.
Fixed the no heat problem, heater core was plugged up; backflushing fixed it. Backflushed the oil cooler while I was at it.

[Jcamper]

Interesting wiring issue. I had reused the octane switch wiring for a switch to ground to activate antilag, it wasn't working. Finally realized I was attempting to use it to sink current and there is a diode in the stock wiring preventing that from happening. Ran a new wire and it works correctly.

The coolant temp according to ms in the stock ecu clt sensor location in top of lower intake runs about 35 degrees cooler than the thermostat temp. I verified with an IR gun, surprising that there is that much consistent drop. Of course I have the heater on, and that temp will be after the heater core. Probably going to move sensor location to a more consistent spot.

[MikeFleming]

Thermostat temp is the temp of the coolant LEAVING the engine, so that should be closest to the hottest point in the system.

Totally expected.

The hot coolant then goes to the radiator where it looses temp, and the water pump pushes it into the front, lower portion of the engine. Coolant then flows rearward in the lower poriton of the block, then up to the back of the head, then forward across the head chambers, exhaust ports, spark plugs, then back to the thermostat.

So it's perfectly normal for the coolant in the low, rear area of the bock to have a colder value that that in the head area.

[Jcamper]

Mike, wouldn't it be reading coolant that had moved out the head (hottest area), through the heater core, and off of the T the goes to the oil cooler? Especially right now since it is 30 degrees out and I am going 70-75mph most of the time (couple hours a day). It is located a bit into the intake manifold, and water should be moving from that location *into* the head. For now I simply changed the fan activation temp to 170 indicated and it is fine, but when the weather gets hot and the heater is off, I would expect there to be less differential between actual hottest water and that sensor location. Less air cooling from the cold outside air, less drop across heater core, more water moving the route you indicated (open thermostat) and less the route I am thinking of.

It is the change in differential that concerns me for setting up the computer. If the differential is consistent then it doesn't matter, I can just set everything up so that 150 degrees indicated is warm (as I have now). However, if the differential changes it will mess things up, fan will turn on when it doesn't need to. Jeff

[MikeFleming]

My first suspicion is that those two sensors aren't reading close to each other. To get a real differential, you will need two properly calibrated temp sensors and not between a $35 CTS and a $4 gauge sensor (and the associated electronic correction curves).

I have some thread-in K-type thermocouples and a dual-input Omega meter I can send you to play with if you want. Pay shipping both ways ...

[brsvo]

Sounds like a great project. And you still drive it that much-SWEET. What kind of milage do you get?

[Jcamper]

Mike, totally appreciate the offer, but I am thinking I will just try to move it so it is within that line moving from the thermostat housing to the heater core. That should always be the hottest temp water exiting the engine, even when the thermostat is closed. Then even if it is a bit off, it won't matter.

I don't know for sure that the temp differential is about 35 degrees, but I am inferring it. My stock gauge reads just a touch higher than it did with the 180 degree thermostat installed (went to a 192 degree thermostat), and the IR gun pointed at the thermostat housing section against the head reads around 190-200. The new GM CLT sensor (thermistor) is obviously an unknown, but it reads right on the money when cold, and it was within a few degrees of what the IR gun said when the car is warm (153 degrees) with standard calibration values in the megasquirt. I suppose I could pull it and check the resistance values in water.

How much do you think shipping would be? It would be interesting to find out exactly what kind of thermal differences exist in different conditions. Jeff

[Jcamper]

Sounds like a great project. And you still drive it that much-SWEET. What kind of milage do you get?

Thanks! Not done tuning it yet. First couple tanks looks like I am hitting about 17mpg with E85. Should get better as I get everything dialed in, and stop attempting to make sure everything's working correctly (oh and hit some upper sections of the load map). I have my timing tables very conservative until I make sure the knock sensor is functioning correctly. I was averaging around 25 before the upgrades.

[MikeFleming]

How much do you think shipping would be? It would be interesting to find out exactly what kind of thermal differences exist in different conditions. Jeff I'd guess $10/US each way.

Those IR measuring tools are sweet!

[Jcamper]

I'd guess $10/US each way.

Those IR measuring tools are sweet!

They really are a great tool. I know they are not super accurate, but they are handy. Plus lasers are cool. J

[Jcamper]

Project update: The car starts, runs and drives like stock during normal driving. However, finally decided to try to get the upper reaches of the map tuned, so I planted the throttle in 3rd gear going up an on-ramp yesterday. Once I reached 3000 rpm things were starting to really go, at 3500 it broke away instantly (this is the northwest, so obviously it was raining), popped up to 4500 before I could catch it. Feathered the throttle back to about half and caught traction again, left it there. At 4000 rpm it broke away instantly again. Plenty of power, need dry roads to make this work. Never got over 18psi during this. J

[Chalky]

Sounds like fun, Just watch for ice:):):)

[Jcamper]

Dry roads and sunny weather today, finally able to try some max throttle. Ended up with a max boost of 30.5 psi, duty cycle was about 85% with an 11:1 AFR at only 4600rpm. Once I get AFRs where they need to be, I will still be pushing the fuel system it looks like. I really thought that 120 lb/hr injectors would give me more headroom. Would like to turn down the boost somehow. Don't know if I am running into boost creep issues or that is just where the stock internal gate is set. I *think* 30psi is about where it was set on my truck, but it's been so many years I can't quite remember (makes me sound old!). Either way, it did seem to accelerate with ... authority. J

[Jcamper]

Got my antilag (ALS) solenoids working; turns out I had a bad relay. Hooned around a little in a big empty parking lot testing it. Works very well. Here is a screenshot of my datalog from that event. Sounds kind of "crackly" and you can hear the turbo spooled up constantly. The power difference is fantastic, like V8 power pretty much everywhere. At idle runs up to about 6psi with no throttle. I will play with the settings a bit, but it seems fairly close. I might just depower the brake booster permanently so that I get used to it that way, runs out of assist after second corner. ALS activated where spark advance drops. 4161

[Jcamper]

This pic shows the ALS plumbing and associated solenoids. They are both 1" diameter, giving lots of bypass airflow. This is why it can create boost without being as harsh as similar systems on rally cars; they are not allowed to add external bypass for air, they jack the throttle open generally. 4162

[MikeFleming]

Are you monitoring EGT?

[Jcamper]

Are you monitoring EGT? No I'm not. I am sure they get up there quickly. Also would be nice to know turbine speed, as I would imagine that could get dicey. I researched what the rally guys were getting away with in terms of timing retard, and I am about half of what they do. My hope is that a relatively mild amount of timing retard combined with high airflow will mitigate the temps. This will only get used for a minute at a time (in few second increments) for autocrossing. I am also thinking about using the "roving idle" feature (injector cuts to keep idle speed down) along with a separate switch to open the bypass solenoids in order to get a ton of airflow through the engine and help with cooling between runs. J