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Another S30 Turbo Project


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While I'm waiting for my resistors to arrive, I also started researching Accel Enrich tuning. My VE maps seem to be pretty close at steady throttle (I'm getting the expected AFR reading at each VE bin), yet under throttle I notice backfiring in my intake manifold and lean spikes. I briefly fiddled with the Accel Enrich settings before taking the car offline for the resistor upgrade, and I noticed an immediate improvement in the crispness of the throttle response.

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Ok, resistors are in place. I took it for a test drive today and it definitely feels smoother! My wastegate must be sprung for 5psi, because my manifold pressure pegs out at 144kpa. This is a good thing - keeps me from straining the engine too much during the break-in period. Once I get a few more miles under my belt, I will probably look into a good electronic boost controller.

 

The 180 degree thermostat is definitely a good idea! The engine is much happier at <200 degrees.

 

I also replumbed my oil feed to the turbo. I had bought one of those eBay turbo oil feed kits with the brass tee and NPT fittings, but the NPT threads definitely did not seat correctly in the engine block. I was tapping the stock oil pressure sender location as my source for the oil feed. I bought a 1/8 BSPT (male) to 1/8 NPT (female) adapter, AutoMeter part #2269, which fit perfectly. It's nice to have Summit Racing's Atlanta store nearby!

 

Long story short, now I'm down to tuning accel enrichments. Basic driving tune is solid. Life is good! Time to start buttoning up the interior and cleaning up my mess.

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Before I get the car tuned, I need to clean up my vacuum connections and install a boost controller. Does anyone have an experience with the HKS EVC-S electronic boost controller?

 

Or I may get brave and just have Megasquirt control boost too. Might as well, since it's already built into MS2-Extra...

Edited by AtlantaZ
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Update on accel enrich: as other articles have pointed out, you really don't need much accel enrich if your base tables are good. I am definitely finding this to be the case. Right now my only real problem is that it runs out of boost too early! The wastegate dump tube is pretty much screaming at anything past 3500RPM and/or 50% throttle. I hope to install the DIYAutotune boost control kit soon and remedy that! :)

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Man, this car is fun to drive. But I may need to move to an automatic soon. As much as I love this car, I might have to trade it for an E46 BMW 3-series. So if you're reading this and interested in purchasing or trading, PM me...

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As I tune, I'm a little confused by the VE numbers I'm getting in Tunerstudio. I expected my VE values at boost to be upwards of 100, since I expect more air/fuel to be forced into (and out of) the combustion chamber at boost than it could possibly hold at static conditions. VE is a percentage of actual charge volume vs. static volume, and boosting obviously force-feeds more air and fuel into the chamber than it would statically hold, so why at 7psi boost am I only seeing 90% VE?

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Holding off on accel enrich tuning until I resolve ticking in the cylinder head. I strongly suspect issues with my hydraulic lifters. I think that at least one of them is collapsing and not properly holding the rocker against the cam. Which means my intake and exhaust valves aren't functioning properly. Which means my tune is definitely off, and I'm sure that I'm losing a bit of power. So I plan to disassemble and clean my lifters this weekend. Found a great writeup from cygnusx1 on cleaning hydro lifters: http://forums.hybridz.org/index.php/topic/50067-p90a-head-ticking-what-to-do/page__st__20

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Got my vacuum distributor block today. I decided that four tees off the same vacuum line was getting ridiculous, and the reference line to my new boost control solenoid would make five. So I got a six-port vacuum block with six 1/8" hose barb fittings, so that each vacuum reference would be consistent. Devices needing vacuum:

 

Blowoff valve

Wastegate

Boost control solenoid

Megasquirt ECU

Boost gauge

Fuel pressure regulator

 

I plan on buying about 10 feet of 5/32" vacuum line from Autozone and plumbing all this up on Saturday. I still feel like the car is missing a certain "oomph." It revs up fine, but throttle response is just not as quick as I would expect. Maybe I'm missing something in my tune...

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Vacuum distributor block installed! I've decided to disconnect the Aeromotive FPR's vacuum reference so that Megasquirt can calculate VE tables based on a constant fuel pressure. I have plenty of available fuel at all operating conditions so far, so I don't think the increased pressure is necessary.

 

I also begrudgingly read the directions for my Speedhut quad gauge (fuel, water temp, oil psi, voltage) and got everything calibrated. It's nice to know where my actual fuel level is! I still need to wire the gauge lighting circuit. I will probably use the green/white wire at the glove box light switch, as this is a very low load and shouldn't overburden the stock wiring.

 

I also cut the inline plug-in style resistor out of the stock tachometer circuit, then connected it to pin #2 on the EDIS module. Tachometer reading is good, even at low revs.

 

I installed the DIY Autotune boost control circuit on the board as well and mounted the boost control solenoid on the firewall, near the battery. I haven't figured out yet how to configure the boost control settings in Tunerstudio. I wired my circuit to JS2, which I think is IAC2, but I'm not sure if I need to just turn Boost Control to "ON" or if I also need to enable the IAC2 port output.

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Vacuum distributor block installed! I've decided to disconnect the Aeromotive FPR's vacuum reference so that Megasquirt can calculate VE tables based on a constant fuel pressure. I have plenty of available fuel at all operating conditions so far, so I don't think the increased pressure is necessary.

 

Looks like you need to read up on how the ECU determines injector pulse-width. If you want your ECU calculating fueling based on a constant fuel pressure drop, then that FPR better be hooked up...

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I'll look into that. In the meantime, I'm now seeing a drop in fuel pressure (at all revs) and accompanying lean spikes after running the car for a while. Even at idle, my fuel pressure holds steady for a few seconds, then dips for a couple of seconds. Here is my list of potential candidates - anyone reading, please sound off on the likelihood of one of these items being the cause:

 

1) Failing fuel pressure regulator

2) Air seeping into the fuel feed (possibly at the tank or pump, as I hear a rather loud "whoosh" when I first prime the pump before cranking)

3) Failing or overheating fuel pump

4) Clogged pump feed

 

When I turn off the engine and let the car sit for a while, the problem clears up. Any ideas?

 

Here's a screenshot of the log file that generates during the oscillations:

Megasquirtleanoscillation.jpg

Edited by AtlantaZ
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Currently soaking hydraulic lifters in B-12 Chemtool cleaner. Will pull them out tonight, soak in oil, and reinstall. I decided to try it without disassembling the lifters. During removal I noticed that two of my lifters were loose and four were overtight, so reinstalling (correctly this time) can only improve things.

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Just to check the cleaning process, I completely disassembled one of the hydraulic lifters that had been soaking in cleaner. There was still black sludge in the bottom. So I can confirm that there really is no substitute for completely disassembling the hydraulic lifters, hand cleaning, and reassembling. I hope to have them back together tomorrow and reinstalled in the car.

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Lifters reinstalled, tapping gone! Engine definitely runs smoother. Boost controller isn't working yet, as the wastegate is always open, but I'm making progress. Need to check my spark plug gapping too, as my local tuner recommends .035 for 10-15psi boost.

Edited by AtlantaZ
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I don't know what your settings are in the MS, but the DIYAT boost control solenoid works like the GM Boost control solenoid, in that it is open with no power connection, and through a PWM signal it closes the solenoid to restrict pressure getting to the wastegate actuator (pressure port).

 

In my case (I'm using a GM ECM), the wastegate duty cycle goes higher to increase boost pressure. Check to make sure this is happening.

 

Also make sure that you have the electrical connections right. Again, I believe the MS uses a similar electrical scheme to the GM ECM, in that the solenoid receives and ignition connection and the PWM signal is on the ground side, check to make sure this is how the DIYAT kit works and that it is connected correctly.

 

*EDIT* I just checked on how DIYAT recommends the solenoid to be connected and what I said is correct, the PWM circuit works on the ground side, while there is a 12V ignition feed to the other connection on the solenoid.

http://www.msextra.com/doc/ms1extra/MS_Extra_Hardware_Manual.htm#boost

Edited by Six_Shooter
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Yep, I wired it per those instructions. Of course, the solenoid itself has no polarity, so as long as you have a good 12V+ switched source and the grounding logic (the transistor) wired correctly, the little sucker ought to be clicking away. My vacuum hoses are plumbed per DIYAutotune's instructions as well, so I'm not sure what's missing. I set the boost duty table to 100 in every cell, just to see if I could get the wastegate to hold closed beyond 7psi, but no luck.

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