Author: sr20tuning

Today I cleaned up the exterior of the car by removing the front lip and side skirts. Lately I had been playing with the ride height, trying to raise it up to keep it legal. The front lip hung so far below the front bar that the car had to be quite high to achieve this. The only trouble was that the bottom of the intercooler had sagged and was hanging past the front bar. The black lip covered it but that was going so I needed a solution.

After the cable ties holding the lip on were cut off, I raised the front of the car by the wheels to bring it to a more ergonomic height. I then put a jack under the intercooler and pushed it up as high as possible without fouling the headlights or reinforcement bar. Next I used some left over pieces of metal in my scrap tub and bent, drilled, cut and ground two new brackets to hold the top of the intercooler firmly in place.

Previously the intercooler was only held in place by a bash plate at the bottom. When I replaced the intercooler that came with the car, I retained this setup. With the load now spread to the new top mounts, I pulled off and modified the bottom bash plate. Some bits were bent straight where they had sagged and one part that was previously only held together with a single nut and bolt was given nine rivets instead. The result is a nice brace that helps support the weight of the core and protects it from bottoming out. The extra reinforcement also adds another jacking point, which while not a strong as the engine cross member, is a lot easier to reach for emergencies or short jobs.

I could now drop the car to the ground and measure the ground clearance. Without the front lip, it was about 130 mm. I took off the wheels and lowered the car by about 20 mm. Sliding a 100 mm block underneath the car shows it clears everything comfortably, making it legal in this respect. The car now has  much nicer stance, like it did when I purchased it, but with less chance of scraping the front or drawing unwanted attention.

With the front cleaned up, it was time to tackle the side skirts. Only a few self tapping screws per side were keeping them attached. They came off easily. Ether side of the doors were patches of adhesive and the bodywork underneath the side skirts was filthy.

So far I have cleaned up two of the four areas, firstly by scraping off the largest chunks and then by using a ‘caramel’ / eraser wheel attached to a drill. This is a big rubbery disc that rubs off foreign substances without damaging the paint. I’ll take some photos of the before and after when I remove some more goo. Another 4 kg was saved by removing these cosmetic parts.

Last night was ultimately successful, with the usual amount of driving mishaps thrown in. I almost didn’t go due to high temperatures and predicted thunderstorms. The clincher was Motive DVD scheduled to attend to film. The drive down was stupidly hot, I think it was about 36 degrees. No air con really sucks sometimes. The LCD read temperatures in the mid to high 80s for water and oil temp on the motorway.

As soon as we arrived, some thick, dark clouds appeared, along with a gusting breeze. This dropped the temperature dramatically, although it looked like it might rain. Fortunately, the rain never came, and it slowly cooled as the night progressed. The Motive DVD thing seemed to be a non event as far as I could tell. We’ll see what appears on YouTube. It was dry and quiet enough to get 5 runs so glad I attended.

Run 1 was pretty good. A semi decent launch and cleanly through the gears yielded a 13.211 @ 110.15 mph. Temperature was still 30 degrees despite the change, so probably as good as can be expected. Being down 1 mph on my best run last time was a good indicator of the tough conditions.

Run 2 was ruined by bogging down off the line. I ran a 13.556 @ 109.76 mph. A bit frustrating but the night was quieter than the week before and I had only waited 21 minutes between runs.

Before run 3 I added 1 degree of timing in the upper rpm range. I also did this last week but apparently I didn’t burn the changes to the board. The run was ruined by enormous wheel spin. I spun in first and then plenty into second. 13.739 @ 113.00 mph. The 113 mph trap speed was my best yet, especially considering how hot it was. My runs last September were with a track temp of only 13 degrees versus 25 at the coolest last night. The car was definitely performing well once it had traction, but launching was proving to be an issue and I had wasted yet another run.

I decided to let some air out of the rear tyres before run 4. I didn’t have a gauge, so counted seconds to keep each side even. I was then loaned a gauge and found that after my blind guess, the rear pressure was still at 36 psi. I lowered it to 30 psi and waited for my next run.

The launch was my best ever. I guess I was lucky that I didn’t bog down with the extra grip. My 60 ft time was 2.000 seconds, over a tenth better than ever before. I still had a bit of wheel spin into second but the run was pretty smooth overall and I crossed the line in 12.844 @ 114.31 mph. My wife gave me a big smile and thumbs up as I drove back on the return road. Finally the goal was achieved! You can see in the purple trace below that once the clutch is let out, the rpm is horizontal, then builds nicely.You can also see where I briefly lift off the throttle (orange trace) after changing into second to limit wheel spin.

I had been whipping out my phone and snapping the LCD to see the AFR and boost traces after each run. Run 4 is below. Note that the air temperature post turbo is at 0, which means it is above the maximum 150 degrees of the probe. In that case, you can argue the intercooler is doing a superb job to cool the air to 41 degrees. The probe is mounted just near the throttle body and would likely have a slightly inflated reading due to heat soak in the piping. Boost pressure is just over 20 psi, increasing a smidgen in each gear. Air fuel ratios are somewhere around 11.5, with a rich spike after each change that the ECU adds as quick throttle movement enrichment.

With no pressure for run 5, I removed a bit more air from the tyres, then butchered it. The launch was reasonable, with some more wheel spin into second gear. The disaster came when I missed the shift to third, and on second attempt, engaged fifth instead. It was a very relaxed ride to line from that point onward. I still ran a 14.033 @ 103.39 mph. I even outpaced the WRX next to me who ran a 14.107.

I’m done with drag racing for a while but I think the car still has a lot more left. My 12.8 run was still average in places and was completed on a hot night. I’d like to go back with better street tyres on a cool night and run a low 12 second pass. If I tweak the power and weight numbers in a drag racing calculator to match my 114 mph trap speed, it predicts an ET of 11.64. This is an ideal scenario with slick tyres and a perfect launch. Realistically, with a better launch on good semi-slicks, I should still find a heap of time.

Another thing that I will continue to do is look for ways to lighten the car. It’s definitely the cheapest way to improve performance. The side skirts will be removed in the near future, and the front lip will becoming off too. This will clean up the looks of the car and allow me to lower it back down without dipping to illegal levels. To remove the front lip, some work will need to take place to lift the intercooler up and patch up the butchered front bar beneath.

 

 

Tonight I will be heading back down to WSID to attempt my 12 second pass again. The weather is stinking hot which won’t help. Even so, I really just to need to nail a launch and three gear changes and it will happen.

Yesterday I went for a drive to buy some stock 13 wheels for drifting. Unfortunately, after some travel time, the larger rear brakes fouled on the inner rim and I had to leave empty handed. The hunt continues for some cheap wheels to go drifting with. I managed to pick up a light weight low profile jack recently, which will make changing tyres at the track much nicer.

The multi-gauge LCD display has been upgraded to include a MAP sensor. The screen now graphs boost and AFR at the same time. The source code is available on the relevant page and a video of the update can be seen below:

Yesterday I spent some time tidying up a few things on the car. There was a bunch of audio wiring that I removed, along with some little brackets and titbits not required. I finally mounted my boost controller properly under the steering column. Previously, it was double sided taped on, but the adhesive had failed and it was falling off repeatedly.

One job I have over the week is to refine the LCD display. The poor quality video below shows the screen for the second run at the drags. The temperatures of the oil and coolant, as well as oil pressure stay on target. Perhaps most impressive it the pre-throttle inlet temp, which doesn’t really move for the duration of the run. The intercooler is doing a great job. The post turbo air temp goes over 100 degrees C mid run and forces the gauge out of range. I will need to adjust this for future runs. I have ordered a cheap MAP sensor to measure and graph boost on the same part as the AFR. When it comes I’ll give it all a slight tweak.

This morning I raised the front of the car by about 15 mm and softened the dampers as much as possible. This should help the car squat and assist with traction at the drags. It will also stop the stupidly low front lip from scraping on my driveway. Today I’m after a low profile alloy jack to take to track vents, I will report back.

Last night I competed at WSID for the second time in this car. The aim was to run in the 12s but unfortunately it was a night of frustration.

My best results last time were a 13.4 ET, 107 mph trap speed and 2.2 60 ft time.

The first run had a half decent launch, matching my best 2.2 60 ft. Everything was OK until I missed 4th gear twice. I crossed the line in 13.416 @ 105.06 mph, which matched my best ET was last time. This was encouraging as it proved the car was faster. A significant improvement was on the cards. The Nistune trace shows a bit of bog down off the line (purple line) and then the missed shift in the middle.

Run 2 was better. The launch had a bit more bogging down, but then the rest went as planned, completing the quarter in 13.198 @ 111.36 mph. A better launch would have snagged a 12 second pass for sure. The increased mph was evidence of the car’s improved potential. For this log I remembered to connect the wide band input, which is shown in green. Mixtures are steady at around 11.5, with a slight rich spot after each gear change.

Run three gave me the best launch I’d ever had. I had the perfect amount of wheel spin to keep the revs up and got out of the hole really well. Comparing the purple trace below to the first and second runs above shows the smooth transition after I released the handbrake. rpm is horizontal and then climbs nicely as the car accelerates. a 2.1 60 ft time proves this.

The car in the left lane was a Volkswagen which also got a great launch (slightly better than me). We were within a car length for most of the track, in fact I believe I was slowly gaining as the time slip indicates I was travelling faster at the 1/8 mile. In my head I knew I was about to crack the 12s for the first time and achieve my goal. Then it all went wrong.

I had increased the boost a tiny amount between runs, which triggered the over boost safety cut of 22 psi on the Turbosmart eBoost controller. I noticed the ‘oBs’ warning flashing in the corner of my eye mid pass. This will shut off the solenoid so the wastegate runs at spring pressure (14.7 psi). The real disaster came when I again missed 4th gear twice in a row. The trace below shows the agonising moments lost as I grinded the gear box. By then I had lost so much speed I only crossed the line in 13.361 @ 98.24 mph. The Volkswagen ran a 12.718. I think I would have run a 12.8 at worst judging based on the fact my 1/8 mile (half track) time was more than 3 tenths quicker than the 13.198 run. Needless to say I was really frustrated.

There remained a 4th run, but that’s where the night got even worse. I got a bit too much wheel spin off line, and with it some axle tramp. The engine cut out after about 50 m. I put in the clutch while rolling and tried to restart it but it wouldn’t fire. Eventually I rolled to a stop at mid track and had to wait for assistance. The first worker on hand was very polite and insisted there was was no oil on the track. I was now hoping for something better than a catastrophic engine failure. A second worker arrived with a quad bike and a tow strap, and he towed me back to the pits. I seemed to be in a lot of trouble from him for not braking fast enough when he came to a stop. The brakes don’t work very well without the engine running to operate the brake booster. Despite the fact I hadn’t done anything wrong, I humbly apologised, but he just kept shaking his head at me.

I firstly checked for blown intercooler pipes, but they were all intact. I then discovered the harness plug for the coil packs had come undone, killing the ignition. The connector was always dodgy but I hadn’t cable tied it after changing the harness recently. The car fired up perfectly and I was able to drive home, which was a huge relief. A night of frustration that could have ended in disaster.

The plan is to have another go next week. Surely it’s time for me to have some luck.

I’ve had a bit of a break from the car lately, which fits in well with the holiday period and double demerits. It’s not that I can’t control myself, but more that I’d prefer to keep a low profile to avoid unwanted attention.

Today I started prepping the car for drag racing at WSID on Wednesday night. I have removed the main carpet for a 7 kg weight saving. The weight reduction page has been updated accordingly.

I also recently updated the ecu tuning page with some information on Nistune Feature Pack firmware which my car is now running.

This afternoon I’ll be dumping the cheap oil and filter and putting in fully synthetic oil ready for racing. I’m planning to install the braided clutch line while I’m under the car.

The LCD multi gauge system is finally complete. The page documenting how to make it is done: Multi-gauge LCD Display. It’s a very long page that chronicles the development process. Scroll to the bottom to see the source code.

It’s great driving with more knowledge about the state of the engine. Oil temp takes a lot longer than water temp to rise for one. The intercooler is very effective as the probe before the throttle reports about ambient 90% of the time. I think I would like to add a cheap map sensor to graph boost on the display at some stage in the future.

My old one was out of date, so today I purchased a new helmet ready for a return to drag racing in early January. I’ll look up what drift is available too since I have the oil cooler and winged sump in place. Fun times ahead.

Work continues on the LCD project. After a restyle and some reliability and transmission improvements it is currently working well. Of course the connectors to wire the sensors to the micro controller in the engine bay are yet to arrive so functionality is limited. All the bugs should be ironed out for when these come, making for an efficient install. A preview:

I have been trying to compare the results for this car with the results from the grey 180sx. To do so, I have ported all of the dyno graphs from the old site to a new results page. Check it out.

I’m home and content with my day. The car ended up making 208 rwkw, which it a fraction lower than the grey 180sx but not directly comparable since it was on a different dyno (both workshop and brand). According to the internet, the dyno at MRC doesn’t read as high as some others. All that matters at the end of the day is if I’m happy with how the car drives, and at this stage I am.

Mark at MRC Dyno was patient, humble and friendly. He didn’t budge on his price and loaded up my car straight away, knowing that I would be hanging around a long way from home. He asked me about the mods of the car and my aims and what image and tuning was already in place.

He first began by getting the K constant and TIM correct. As the Nistune documentation suggests, he held the car at about 3,000 rpm on light load and played with K until the short term trim was zero or within 1%. After this, he started holding the car at higher loads on the dyno to assess how the open loop mixtures compared to those predicted by Nistune. He soon had the the TIM set so that the actual AFR was within 0.3/0.4 of the Nistune numbers. Mark was also able to tweak the fuelling map so that the ECU no longer held closed loop in 4th and 5th gears at low boost.

The first power run took place on minimum wastegate spring boost. The mixtures were instantly on target throughout the rev range. The external wastegate was struggling to pass enough gas, with boost creeping up to 17 psi at high rpm. At this point he started to gradually increase boost. At 18.5 psi, the intercooler pipe on the hot side blew off. This was the one that I had to cut to make fit. As a result it was missing a bead and vulnerable. I asked Mark if they had a bead roller, to which he replied that they did and I could roll a bead on the pipes if I wanted to pull them off. Below is the before and after. This should never happen again unless a hose camp were to fail.

After a short break, Mark continued the tune. He eliminated an over enrichment on application of throttle that was seeing AFRs of 9/10:1. He also fixed the idle by making it richer and back at the 850 rpm factory target. He checked the base timing as well to be thorough. Some more power runs took place at higher boost, Mark stopping at 19 psi because of the track work I intended to do. He pulled a lot of timing out around peak torque to stave off potential detonation on the track and left the mixtures a fraction on the rich side. I get the impression this is a conservative and very safe tune.

On the road, the car didn’t feel a huge amount quicker. It doesn’t hit with the same force as the HKS 2510 did on the grey 180sx. It still surges onto boost, but the power really builds up until 7,000 rpm. The lack of mid range is due to the missing VTC. I am likely to buy a new VTC unit and refit it at some stage. There was a lot of discussion over the cams in the engine. They made good power up top compared to an S13 SR20DET with stock cams. This might just be due to the standard VTC cam in the upper rpm optimised position.

The car is a lot more driveable without the rich spot then lean mixture as it starts to boost. Lag is reduced and the car is driving very well. I expect to take a big chunk off my ET at the drag strip next time out, assuming I can launch the car. Increased mph will be indicative of the new power. I feel the tune is safe enough that I can use the electronic boost controller to bring the turbo on quicker, even it causes a boost spike. I will experiment with this in the coming days and likely bolster the mid range.

On way home I had the registration safety check completed on the car and picked up the engine bay plastic enclosure for the multi-gauge system from Jaycar. All I need to finish that system are my waterproof connectors which will arrive any day. The aim is to drill holes and epoxy one half of the plug in the plastic enclosure. The micro controller wires will then be terminate to the inside of the plug, and the sensor wires in the engine bay crimped into the other half of the plug. The sensors then plug firmly into the enclosure. This should be waterproof, strain proof and reliable. Everything is being documented and will appear on a new page in the near future.

I need to get a new helmet and then I’m super keen to hit the track again.