Tassuperkarts GX Turbo (Updated again!)

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Post by tassuperkart » Sun Feb 23, 2014 9:39 am

LOL
Cheers Benny! Good to see ur still lurking!!!

Oracle
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Post by tassuperkart » Mon Feb 24, 2014 10:49 pm

So i got a little busy today.

I moved the old damaged GX off the hoist (finally)and onto the old farm trailer. I still have to remove the doors and the hatch and some sundry interior parts yet.
Ill take it down to the dead Pullstart cemetary down behind the dam and later on taken to the crushers.

Its a little sad for me actually. I have had lots of fun and good times with this particular car for well over 15 years and its been a very reliable and faithful old shitter. I never get rid of cars that I like and get quite attached to them so... yer....

Cya old friend. We've had a lot of fun and games over the years but its your time now!!

RIP "The Rat"!

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Moving on.

I put the ET onto the hoist and dropped all the underside goodies and lifted the old stock as a rock engine out.

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No big deal here. All pretty straight forward.

Hes a pic lowering the good engine into place:

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Got a little late so fun and games ended for the day. I just have to connect up hoses and wiring and give the wifeys old ET a new life!
Oracle
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Post by tassuperkart » Tue Feb 25, 2014 9:25 am

I also fitted up my new tough rear engine mount.
The stock engine mount has a habt of sagging down, breaking and generally allowing the engine to float about too much for my liking. Many gearshifting hassle originate from the back mount problems.

I was very reluctant to make a solid mount that many other car brands have made for them. Unless all 3 mounts are solid, the engine can still move around at the front and this will result in eventual cracking and failure of the rear mount, or worse the chassis area where its bolted up to. The noise into the cabin is also unacceptable for a daily as well.

Ive taken a different approach with a flexible urethane mount that will allow limited sideways movement and hopefully not transmit too much engine noise into the chassis. Will serve as a test.
The original design was a much softer, but still solid rubber mount to allow limited movement and reduce transmission noise into the cab but this particular aftermarket urethane engine mount came around at the right price and in exactly the same configuration that I was going to fabricate and saves many hours of fabrication work so fuckit.

I couldnt easily fettle the stock chassis bracket so I fabbed up one from square section RHS.
This one is made from too light material so I glued on some webs to prevent the bracket from spreading and bending down.

Final version will be made of much tougher material but this job serves as a test fit and position job.

Here:

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Things I hate:
Broken gearshif x-member. I have a couple of spares on the wrecks but not easily gotten so since they are laying on their bellies....arrgh

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Forcd4 wrote:Oh fuk no dude it's you a again, the oracle.

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Post by tassuperkart » Tue Feb 25, 2014 8:26 pm

More progress today.
I was very lucky that i was just able to get to the shifter setup out of the old shell!! Yay
So that installed and the last of the mechanicals, like exhaust and so-n are added.

What at first appears a simple and straightforward engine changeover is taking a lot of time as there is a ton of additional bits and bobs that were added to the old Rat over time.

This means remounting the FPR, the MAP sensor, Idle speed solenoid valve, ignition trigger, ignition coils, and the engine fan.
Along with this is fit different plugs to the reverse light switch and the radiator fan.
Doesn't sound much but is quite time consuming when added up. Quite a few hours actually.

I dont use a stock lower radiator hose and my engine inlet elbow points straight down rather than across towards the dump the stock hose does.
It was done this way to suit a different radiator way back when. There is no provision on this cars radiator for a hose return like there was on the ET radiator.
I originally made a short 180 degree adapter pipe and the hose then runs back up and onto the radiator. Means I just use some generic straight hose and a 90 degree elbow rather than an expensive and hard to get OEM lower hose..
The adapter i made at the bottom also needs to carry the heater return hose so i welded on a hosetail for that purpose.
Trouble was I didnt allow enough room for the dump pipe and the heater hose ran hard against the dump. Fukfukfuk. Teach me to do it without checking with the dump in place.
Pull it all back out, cut the hosetail off and add a 90 degree elbow to it re-weld, paint and refit. Its a total PITA to do up the 4 hose clamps and its all fiddly to get to.

So a shit-ton of fiddly-arsed and time consuming little jobs have been completed and the task of removing the stock EFI loom and separate the wiper/washer out of it begins

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Rather than cut off the wires Neanderthal cave man style, I removed all the individual pins out of the big plug leaving just the wiper/washer wires.
Tape it all back up and connect up.

With the old efi loom finally out of the way I fed in the new loom.
No real biggie this one as it all connects up easily on the engine side and all i have to do is add a power relay for the injector power supply and pickup the original ignition power out of the loom.

Last task is to change the fuel pump relay from +ive side to -ive side switching.
Strangely, the Nissan ecu pulls the relay in on the positive side. However its a fairly simple matter of cutting the original black earth wire at the relay and attaching that to switched power on the other leg of the relay.
Keeps everything original looking, neat and tidy with no additional pesky wires run here and there.

I ran out of time and still need a few hours to finish off the wiring and do sanity checks before firing it up.

More later.

Oracle
Forcd4 wrote:Oh fuk no dude it's you a again, the oracle.

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Post by tassuperkart » Sun Mar 02, 2014 1:15 pm

So, sanity checks, double checks and idiot checks done i put some power to the system and all looks good.
The engine has been sitting upside down for quite some time and gives a big cloud of smoke and soon settles into its characteristic hard idle!!!

Once all hot and cooling system bled out time to do another sanity check of all the hoses and fittings.
I had a leaking turbo oil fitting I hadnt tightened up more than finger tight (its the little things that a: take time, and b: ruin your day...thank myself for constant double checcking....)

Also that fucken lower radiator hose adapter was leaking from a pimhole in the brazing.... Up on the hoist, out with it again and re-braze it........

Took it out for a run this time and its running as sweet as you like and making really good torque right up thru the revs with the oddball turbo. Very pleased with that result.

So, time now to start adding some cool little features Ive had in mind.
Ecu controlled closed loop boost control and launch anti-lag control.

Happily, the ET has a speed sensor built into the instrument cluster so thats makes things really simple. The reed switch in the dash simply switches to ground which suits the operation of the ECU perfectly so I connected into the main loom at the big multi-pin plug using the wiring i had originally extracted.
Its a benefit of actually removing the pins and unused wiring from the big plug rather than just cutting the wires off!!!!

So i run the VSS wire from the ECU and straight into the plug nice and neat like.
Next job was to wire up a clutch switch. This is easy. The ET only has a brake light switch. The GX has brake and clutch switches... dunno why. mebbe a start inhibitor in Europe or somewhere.
The switches are identical and the ET has a stopbolt where the switch goes so its a straight wind in and connect one side of the switch to ground and run another wire to the ECU MVSS input! Done!

A couple of people have asked me about my DC/DC "Buck/Boost" switchmode power supply for the injectors. When the motor had a Microtech, there was no dead time (injector dwell) correction and with the big (036) injectors the lack of dead time correction was causing the engine to lean out and stop when the lights and fans came on......

Here: Just ignore the rats nest of unfinished wiring.. Itll be tidied up eventually

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It hold <>14.5 volt injector voltage regardless of the battery voltage.
here the engine is off, ignition on. Input voltage bottom left, Injector voltages top right!

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I dont need it with the Adaptronic as it has dead time correction tables but I dont have the correction factors handy for the 036's so ill leave it in for now.

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I fitted and wired up the solenoid valve (MAC valve) for the boost control. was a couple of handy holes in the strut tower!!!!

Also, I solved the issue of no tacho for the ET when multiple coils are used.
The tach is an inductive type that requires +12v from the coil and the back EMF voltage spike after the coil triggers to work.
Most aftermarket tachs will run with a simple 0v - +5v waveform common to just about every electronic tach output known to man.
The issue can be gotten around by using diodes on the coil outputs to drive the tach, a method I dont particularly like, or make a simple tach driver.
I used the stock single coil trigger connected to a spare ignition output on the ECU configged for Tacho.
The coil trigger drives the coil out of an old 12v relay. The relay coil behaves in much the same way as a tiny ignition coil and voila, instant tacho input.
If you use this method, make sure you open the relay case up and the little contact points arm out of the relay or it will click in time with the tach pulses.!!!!!! Its loud! I tried it!!!
Forcd4 wrote:Oh fuk no dude it's you a again, the oracle.

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Post by tassuperkart » Mon Mar 03, 2014 9:17 am

The clutch switch works well and basic launch control works fine. I set it at 3000 just to play with.
This will also enable flat shifting as well so no need to lift the throttle during hard gear changes.

Next was a good launch anti-lag. This setup requires a working speed sensor so the launch function does not enable while driving along!!!

The ET speed sensor is a reed switch and annoyingly, the Adaptronic ECU does not interpret the signal very well due to reed contact "bounce". The ecu is easily confused by the inconsistent signal so the KPH readings in the interrogator are not really believable, but it serves well enough to tell the ECU that the car is actually moving or not and thats what matters.
I have a few strategies to try electronically to see if i can "clean" that reed switch signal which i will try after a trip to Jaycar for a frikken 25 cent capacitor an diode!!!!!

If i cant get a decently clean reading from it ill consider fitting a dedicated hall effect sensor to the inner driveshaft CV or see if i can find an inline speed sensor that goes between the gearbox and the speedo cable...
Id much rather have something on the speedo cable tho as one wheel may not spin in which case traction control will not enable. However, the speedo reading will increase due to the inner wheel spinning. Altho still not ideal, its close enough to get a meaningful traction control working.
I have also contemplated drilling the differential case an fitting a Hall device looking directly at the diff crownwheel teeth.
Not overly keen on this strategy due to drilling holes and sealing oil issues......

See, traction control requires a certain amount of wheel slip to actually enable. Exact reverse of ABS.Its a ratio of turns between the front wheels and rear wheels. only really need one rear wheel sensor as it unlikely to have a locked rear wheel while hard on power!

Its called "Target Wheel Slip" and getting the right balance between targeted slip and "Effort" to reduce slip by either pulling ignition timing out or invoking rev limiting in gross cases is a very tricky thing to get balanced out right. A wheel speed sensor on one front wheel will obviously only provide control turning in one direction.
If i setup 2 sensors on the front I can get TC with one wheel spinning but not with both.. or very unlikely anyway!!!!!!

I dont have enough VSS inputs on this older Adaptronic to run dual front and single rear VSS which is the best compromise on a FWD.
Obviously 4 wheel VSS is ideal. Shall see with this topic.

The launch antilag works really well and at 3000rpm I can produce about 7 psi boost in neutral with plenty of satisfying pops and bangs out the exhaust!!!!!
I currently pull about 45 degrees of timing and add 15% extra fuel.

Next was some on-road time to sort out duty settings for the boost controller.
I just set 40% across the board to start with and that gave a satisfying bump in boost to about 12 psi. Plenty powerful enough but not enough to give a stiffy.
60% duty gave a big thump with about 16 psi or so which fried the tyres easily immediately to the limiter in 2nd on an easy rollon untill the fun and games ended with a boost pipe blowing off the intercooler.

For some reason, the silicone 3-2.5" reducers are extra thick and I havent got a T-bolt clamp handy to fit where I can actually push the pipes into the coupler........

I had used some stout hoseclamps over the years but only at lower boost and these gave up one it got asked the higher pressure question.
Additionally, the pipes Im using are just exhaust pipe where i ground in a couple of grooves with the edge of the grinding wheel to provide some grip for the silicone. Rather than having a proper hosetail/barb raised ring/keeper thingo on the end to prevent the hose from ever slipping off even with light clamping.
So, I pulled the pipe out, ground additional grooves and used 2 hoseclamps on each coupler. I reckon they will keep the pipe on. If I blow one off again, Ill remove the piping and braze on some blobs to act as keepers.

Once I sort the speed sensor issues, Ill setup boost thru the gears. That, launch anti-lag, flat shift and TC working together should make for a really cool little car that will put all its available power to the ground rather than having to pedal it trying to control useless wheelspin which is sketchy at best!
Of course, I have an override for TC and boost control for those times that require additional hooligan factor!!!!!

Oracle
Forcd4 wrote:Oh fuk no dude it's you a again, the oracle.

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Post by tassuperkart » Thu Mar 06, 2014 7:08 pm

I gave up on the stock speed sensor. Perhaps its a case of almost 30 years and a couple of hundred thousand K's........

So, after a little research I came up with an elegantly simple solution, this:


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A simple inline Hall Effect speed sender from a Terratrip rally computer!
70 buckeroonies off the shelf at the local speed shop and we are in business!!! The ecu needed to be calibrated to the sensor and now I have a rock steady and believable speed indication!!!!

So, having this now means the launch/anti-lag function is working perfectly. WOT and stationary and it sits at 2700rpm at 8psi boost!!! Should be good fun for fast traffic light getaways!!!!

Another function the requires a reliable speed signal is boost thru the gears. The ECU looks at the wheel speed and the RPM in each gear and determines which gear its in and sets the boost pressure I have set in the boost control table according the the RPM and the gear!
Currently I have stock wastegate pressure, 8psi in low, which is still way too much power but traction control will have to take care of that.
10psi in 2nd
16 psi in 3rd and up.

I need to do some testing to sort it out to get maximum power without wheelspinning.
Again, traction control will take care of any issues beyond that.

Another handy feature I have enabled now with a cammy and tuned engine is closed loop idle control.
The ECU will only invoke closed loop idle either in neutral or stationary. Since i dont have a neutral switch, its roadspeed related only.

Here, the ECU takes full authority over idle speed rather than just presetting a fixed amount of air going in via the idle valve as is the case now.
Idle speed can vary quite a lot depending on various factors and the engine will sometimes race a bit and then chug away at too low revs. The flywheel is very light and cam is pretty tough. The engine runs very happily and reliably at 1150rpm idle but go much slower and it runs quite roughly and inconsistent on idle.

So now, the ecu attempts to control idle speed via the idle valve alone and its quite cool watching the idle effort in the guages window scaling up and down keeping the engine in a control band! Cool stuff!
Often with engines, especially tuned engines, a sudden big blip of the throttle on idle will result in a quick rev and then the engine drops down past the desired idle speed and then "catches" back up. however, often they will stall.
Altho the ECU does have 2 "recovery" rpm presets where it will idle up to catch a stalling motor, if the engine is not fully warmed, or shut down and run again a few minutes later how, the idle speed will often "bounce" on the first recovery step and sit there alternately revving up and dying down a couple of hundred rpm until things stabilise which is a pain and sounds stupid!!

The closed loop idle control takes care of all that and the idle simply drops off after a blip and gracefully fall down to preset rpm.
I also added some "Calmdown" effort which is a few steps of air (dashpot) on throttle off to slow down the rate of rpm loss as the engine approaches preset idle speed!!!!!!

Working beautifully. Ive got to do a couple of cold start logs and a few driving logs to have a look at whats going on idle and boostwise!!! I need to set the boost control to just explore wheelspinning and then let traction control take over.
Its easier to control marginal traction that try to control stupid power and crazy wheelspinning!!!

So, what remains is to fit a single Hall Effect sensor to a rear wheel and then i can invoke full traction control to maximise everything I have under the bonnet now.
Im looking forward to that task. The car suspended quite stiffly and is very prone to wheelspinning when cornering even at highway speeds and pedaling the engine to reduce wheelspin is very slow way to go.
Letting the electronics handle the task is quite a cool idea to me!!!!

Strange feeling thing tho is that Im getting towards the end of development for this little car and i have no further plans as far as any more power is concerned. Its making very good power at 16psi on the fast setting, something around 140Kw, and I see little if any reason to add any more other than purely for bragging rights. Not interested in that.

Dyno Figures alone are for fags as far as Im concerned.
I like to drive and ENJOY the thing!!! Im tempted to do a coupl e of local hillclimbs to be honest!

Oracle
Forcd4 wrote:Oh fuk no dude it's you a again, the oracle.

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Post by tassuperkart » Sun Mar 16, 2014 5:58 pm

A very strange issue reared its head with a short hesitation, kinda like a quick lift of the throttle and back on again.......

I thought I might have had a wiring issues with the fuel pump or perhaps a failing fuel pump as the problem reduced when i filled the low tank.

While it was playing up, i took a couple of ECU logs and got a couple of really good instances:

Image

The middle red trace is injector opening time
Below is the AFR and fuel trim traces.
You can see the injectors time dropping off, the afr trace leaning off and the fuel trim spiking like mad to try and compensate.

So nothing wrong with the fuel pump but the injector trace dropping off is odd.
In the end, I did some re-wiring. There was several different power supplies along with the DC/DC converter all giving different voltages into the back end of the ECU...
I dont know exactly what the issues was but now all the power supplies are supplied by 2 power relays and i also deleted the DC/DC converter.
I only had that in place for the Microtech as that thing doesnt have a lag table but the Adaptronic has an injector lag time table so with a little trial and error, i filled out that table with corrections and the thing fired up and runs as sweet as ever.

Subsequent log traces show further improved and flatter traces as well. I cant explain that but its all good!!!!

Oracle
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Post by BennyET » Wed Apr 09, 2014 3:40 pm

Any more progress E? Drifting vidz???
I understand the need for conformity. Without a concise set of rules to follow we would probably all have to resort to common sense.

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Post by tassuperkart » Wed Apr 09, 2014 5:40 pm

Drifting vidz.... baaahahahahaha

Just some further electronic tweaking really.
I upped the boost in 2nd gear from 12 to 14 psi. The tyres generate such good grip. It struggles to hang on now!!! Traction control will take care of things.

The clutch is struggling to hold 16psi in 4th tho. Having said that, the clutch faces were pretty rough with some pronounced grooves from the brass button clutch and it might take quite some time until the organic plate beds itself in fully.
I should really have had the flywheel skimmed but the pressure plate was in need of a skim as well..... all getting too hard having to disassemble the pressure plate to remove some bloody grooves........gah. Fuckit, it'l bed in eventually

I still dont really know what those strange hesitations are tho. I had a though that it may have had a connection issue with the fuel pump but looking at the logs its happening at ECU level....... Actually cuts the injector pulse. The WBo2 sees this and the ECU attempts to trim up to compensate........ very odd.
Its had one or 2 tiny hesitations since I rewired everything so.. well, I'll just have to leave it until it actually fails Im guessing!

More later
Oracle
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Post by tassuperkart » Wed Jul 09, 2014 9:47 am

Not a lot happening with the Pullstart.
Its mostly electronic tweaks and ongoing fine tuning really.

Ive had some odd issues with idle speed control which is handled by the ECU.
I first set open loop idle effort. This is just a specified number of idle valve steps set against coolant temp. Pretty straightforward.

Closed loop idle control is then specified. Even tho the cam is pretty big and the flywheel very light, the ECU controls idle speed very well with a nice and consistent idle around 1200 rpm.
Thing is, just occasionally, the ecu drops idle effort well below even the open loop presets and the engine sits there "bouncing" on the idle speed recovery settings (anti-stall). After about 10/20 secons, the ecu seems to realise that there is a problem and all things become normal like nothing happened at all...
It makes no sense to me what the ecu is trying to achieve and the log traces dont seem to show anything strange.......?
I reflashed the ecu with the latest firmware as my version was very old. This seems to have helped but the issue hasnt gone completely away.

As a workaround, I have opened up the throttle butterfly so that when in closed loop idle, the ecu is only applying about 5% opening to the idle valve. Now the idle speed will only drop a hundred revs or so at worst.
Also means that i had to re-write the open loop idle tables as the engine will rev its head off in open loop conditions!!!!!!

Lots of fine tuning and tweaking have gotten some very pleasing afr figures. Its nice to cruise along at 100kph and see the afr's sittng in the mid 14's and gently easing back to the high 13's on 0 kpa manifold pressure.
My low boost afr's sit around the low 13's and full power runs in the mid 11's.

If anybody is interested here are the Oracles ignition settings. Of course, no responsibility is implied or taken if your engine grenades on my secret recipie!

Idle timing is 12 degrees
Zero Kpa ignition timing advances from 12 to 32 degrees @ 4000rmp with a further 2 degrees advance up to 7000rpm
Boost retard is more or less 1 degree/psi.
Vac advance I add about 8 degrees at 20"Hg. Steadily reducing to zero advance at 5"Hg.

Dont ever say that Im secretive with my tune!!
I run a few less degrees of idle timing than stock to help soften and smooth out the idle.

Ive not run these settings on a dyno to see if there is more powah to be had at 16psi boost pressure but the engine seems quite happy and detonation free and that'll do me for now.

I have an 160k return run to work each day with a mix of hilly open 100kph highway, thru the city and then a relatively flat freeway 100kph run and Im seeing economy figures of a bees dick under 13 k's/litre. (12.8). This hovers around 33-35mpg in the old money which is pretty handy economy for such a state of tune when your loading it up with BP Ultimate 98 at a dollar-eighty a litre as we do in Hobart.

Gotta be happy with that!!!!!

Oracle
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Re: Tassuperkarts GX Turbo (Updated again!)

Post by tassuperkart » Fri Jun 02, 2017 10:52 pm

Well, the time came to let the beloved Pullstart go.
Things have changed in my life and I had to do some re-organising of lots of things and thats about it.
Josh (ETKing) is now custodian of that ballsy little car and i hope he has as much fun in it as i did over the long time that i had it.

Ill still be around the forum as the Oracle tho. If nothing more than to be a plain and simple cunt! Or dispense some wisdom If I still have any!!!

Cheers
Oracle
Forcd4 wrote:Oh fuk no dude it's you a again, the oracle.

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