ReplicaR's daily/AutoX build thread Ver. G37S

[ReplicaR]

Not too long ago I bought a Hotchkis front sway bar for the G37S. This weekend I finally had a chance to test it and see if there is any actual difference in performance. First, let us examine the bars themselves. The bars are labeled in the image, but it is clear that the Hotchkis swaybar is significantly larger than stock Infiniti bar. According to Hotchkis, their bar is 205% stiffer than OEM Sport package bar. What does that translate to on the autoX course?

To find out, I went to a local autox course, and ran about total combined 16 runs split across 4 sessions. First two sessions were 9 runs, which allowed me to get acquainted with the layout of the course, and set some baseline laps. In between session 2 and 3, I jacked the car up, took off the original sway bar and replaced it with Hotchkis unit. Right away I’ve noticed how much more planted the rear of the car is. The one complaint I’ve always had about this car is that the rear is very loose, and doesn’t really give a lot of confidence. That’s definitely not the case now. The new sway bar has increased the front roll stiffness sufficiently to the point where the grip balance is more neutral, and perhaps even leaning towards understeer. In the remaining sessions, I was able to be reacquainted with the car, and relearn some driving techniques, including carrying more speed into the corner, and getting on the throttle earlier.

End result of all this testing was very encouraging. In the stock form I was able to run the course in 41.6 seconds as my fastest time. Once the sway bar was changed, I was able to improve that to 40.8 almost right away, and with a little more confidence boost, I cracked a 40.2 second run. 1.4 seconds on a small mostly tight course. Out of the mixed field, I finished 3[SUP]rd[/SUP] outright, only to be beaten by a supercharged Miata, and Abarth SS on some race tires.

 

[ReplicaR]

As promised, here is the video.


https://youtu.be/6RHfEeOiLkY

 

[ReplicaR]

A few days ago, I decided to test what would happen if I were to pit the K&N Typhoon intake vs stock intake head to head on the dyno. In order to keep the conditions similar, I would let the car fully warm up, make a couple of passes on one intake, then swap the intake out while the car is still strapped, let it fully warm up, make another couple of passes, and then drop in the filters, and repeat. AFR was pretty much identical between all intakes, so no ECU learning or adjustment was required. The hood was down for all the runs during this test to simulate real world experience. The order in which the intakes were dynoed was Typhoon first (since it's already on the car), stock, and then K&N drop ins.

First up was the K&N Typhoon intake. The intake itself seems like a nice piece, and they try to provide some kind of heat shield, to keep the hot air out of the filters, but air filters are not fully incased, so it still sucks in a good amount of hot air with the hood down. The initial run yielded about 270 rwhp in 4th gear. Two runs were within 1 peak hp of each other.

Next, I removed the K&N intake, and installed a stock intake on there with whatever the part store filters were inside when I bought the car. What was kind cool to see in the process is was how much R&D goes into these systems today from the manufacturer. The air filter element had a direct path to clean fresh air from the outside of the car via a duct, and the intake was not getting any more air anywhere else. Also, it was kinda cool to see a Renault stamp on the throttle body, a reminder of the time when a French manufacturer came in and rescued Nissan.


Engine without intakes

Renault Nissan Hitachi

OEM intake air ducts

Intakes installed

Second run was done on stock intakes and stock filters. What was really interesting was a pretty large difference in the middle of the curve, which I can’t really explain between the two runs. None the less, the peak number was within 1 hp of each other, so I’d say that’s a repeatable run. Peak number on 278 rwhp.

Final piece of the puzzle was to run stock intake with K&N drop in filters. Just as before I would let the car cool down, swap out the filters, and bring it back up to the temperature before making the runs. The two runs went pretty much hand in hand, power numbers were within 2 hp of each other. Peak number was 283 rwhp

Now, if we take these graphs and overlay them on top of each other, we can see the picture a little clearer. With every iteration, you can see a clear step up in power. The car gained 8 rwhp peak going from K&N Typhoon to stock, and then again 5 rwhp peak by dropping in K&N filters into stock intake.

The peak is not the most shocking difference though. Here is the layout of just Typhoon and Drop In filters. The biggest gains weren’t at the peak, but rather in the middle of the powerband. 16 rwhp and rwtq at around 5k rpm, the rest of the range is between that and 12. Those are some solid gains, and definitely something worth doing.

But wait, there is more… Usually when you dyno the car, you’re supposed to do pulls in the gear that’s 1:1, for the most accurate number on the dyno. This was not a possibility on my car, because 5th gear ran into speed limiter, but I had the dyno operator making the pull in 5th anyway, and it produced 5% more power throughout the band before it hit the speed limiter. If I were to do the math, this means that unlimited and in the correct gear, the car would have dynoed 296 rwhp. Not bad for something that’s totally stock with drop in filters.

The takeaway: The truth about this dyno test is, it was not completely necessary. I was always going to switch back to stock with K&N drop in, because SCCA Street class doesn’t allow aftermarket intakes. But knowing what I know now, I will never look back and think that I’m missing out on power. I will definitely miss the vroom-vroom from Typhoon, but knowing that I have 13 rwhp addition definitely makes up for that. I believe that the thing that really hurt the K&N Typhoon is that it keeps the air filters inside of the engine bay, and doesn’t really do a good job of keeping the hot air out of them. With the hood up, it might have made similar or more power than stock with K&N drop ins, however I don’t drive with hood up, so that scenario was out of question. The moral of the story here is, if you do get a cold air intake, make sure that the filter is either fully encased and gets its air from outside of the car, or is mounted outside of the engine bay.

 

[ReplicaR]

So, this is the review of the actual catback. Back when I was doing research on which catback I want to get, I wanted to make sure that whatever I get will at the very least be a quality piece. Improvement in the sound was a requirement, and if I were to break 300 rwhp mark, that would be cool too. If you guys remember, the car made 284 rwhp in 4th, which would have been 296 rwhp in 5th (1:1 gear) if it hadn't been for the top speed limiter at 145 MPH).


From all options, Invidia seemed to make the most sense, and after reaching out to them directly, they were able to give a better price, so I decided to get Invidia.


The good: Invidia has a pretty quality built exhaust, and I was overall very satisfied with fit and finish, although there was a problem with the fitment of the tips. My guess is that at some point they changed the diameter of the piping, because the website mentioned 60mm pipe, but in reality it's 2.25 inch inside diameter, therefore tips were for bigger pipe, and required a trip to muffler shop to have them welded in. The rest of the piping is pretty good, nice smooth bends, clean welds, nothing to complain about. The exhaust is definitely on the quiet side. At idle it only registered 63 DBs (57 DBs stock) and at wide open the meter peaked at 89 DBs (87 DBs stock). During the daily drive, it's barely noticeable, which is actually great because I didn't want a loud exhaust or something that would annoy me daily.


The not so good: This exhaust is heavier than OEM catback. OEM complete system was around 61 lbs, while complete Invidia kit is around 73 lbs, so total gain of 12 lbs over stock. The power isn't terribly impressive either. While it is a substantial step up in pipe diameter, particularly in the rear section where it goes from 1.5 to 2.25 inch diameter, the chambered muffler slows down the flow of the exhaust, and therefore on the dyno it only picked up 4 rwhp at the peak. Most of the power difference was up on top, above 5500 rpm.


Test conditions: All the testing was done on the same day roughly 1 hour apart from each other. All pulls were done on DynoJet dynamometer, in 4th gear due to top speed limiter restriction. In 5th gear (a true 1:1 gear test) the car was making 5% more, so you do the math. Before people start chiming in how this requires a retune to fully optimize the catback, the tuning is not actually required. The Air to Fuel Ratio was the same between two runs, nothing else is changed. The tuning that you would do on a catback would affect stock setup in the same exact way.


Chambered vs Straight Through Mufflers: After seeing the results of the dyno, I got curious to see what would happen if I were to do a simple muffler swap. I went to the exhaust shop, and had them cut out the Invidia Muffler and replaced with Magnaflow Performance Muffler setup. While the sound at wide open throttle improved, the overall experience just turned into total misery. With my daily commute and the fact that the car is automatic, I was stuck almost exclusively in the drone range of the motor, which means that by the time I would get anywhere, I would have a splitting headache. I didn't even bother to find out if the straight through made any more power, because whatever the difference was going to be, I knew that I would not keep it like that, and would opt for quiet over 10 hp max.


Now, for a bit of show and tell.


https://youtu.be/lwLx9UPu2gM


Stock Exhaust.

Stock pipe diameter vs Invidia pipe diameter

Invidia Q300 Installed

Dyno Comparison

 

[ReplicaR]

So, the start of the season is right around the corner, and I'm stuck here with no class correct wheels at the moment. As some may recall, I decided buy a set of stock sedan sport wheels I knew were bent, keeping in mind that I'd be able to fix them for about 120 a wheel. About two weeks ago, I take them to a repair shop, and they tell me that not only 2 wheels are bent (I was under the impression that only 1 wheel is bent), but they also have wobble, which basically means that they are not repairable.


I get on ebay and order two of the replacement wheels, both supposedly tested and 100% straight and true. Wheels get delivered, I take them to the same shop, one of the new ones is bent, same exact way. It appears that the factory Enkei wheels are just notorious for being damaged beyond repair. We ended up ordering another wheel from a local wheel warehouse, this one is supposed to be good this time around. The wheels will be refinished in gloss black, since I think they are just really ugly, and that should cover up all the ugly.


Another update is that I've ordered a set of tires for competition as well. Ended up going with a 245/40R18 in front on a 18x7.5 inch wheel, and 275/35R18 in the back on a 18x8.5 inch wheel. The width is pushing the limits a bit, but should still be alright. Overall height of the wheel is actually 1 inch shorter than OEM, but that means that I'm taking half inch off sidewall, so if anything that should help with tire rollover, and make it more responsive. More updates and pictures soon, wheels should be done next week.

 

[ReplicaR]

Well, here is another update. As the first weekend of the new season nears, I am making sure that I am ready to go as far as all the possible mods are concerned. The final modification that I'm allowed per class rules is to replace the shock damper only. From off all the off the shelf options, Koni made the most sense. In the last few days, I was able to get the shocks installed, but also just for my own curiosity, I decided to dyno stock dampers as well. Stock dampers turned out to be made by Tokico, which was a pretty cool thing to know I guess. Anyway installation pictures.

Driving impressions: So far I've had the shocks on for about a couple of days, driven the car for a few miles. Right off the bat, I've noticed that in full soft Konis are actually softer than OEM sport package Tokicos. More on that later. I ended up adjusting the dampers about half way to stiff, and that gave me the compromise of ride comfort / sportiness I was looking and was used to. Another thing that I can say about Koni is that the shocks are more progressive than stock ones, they don't transfer as much into the chassis, which is definitely an interesting feel, I'm not sure how I feel about that yet.


Dyno testing: As I've stated previously, I tested Konis on the shock dyno before I installed them. After the stock dampers were removed, I've decided to test them as well. Let's take a look at the graphs, and see what they tell us. By the looks of the graphs, Infiniti actually equipped pretty nice shocks on this car, which would explain why it's so composed from factory. The one thing that you can see though is that left to right, OEM dampers are pretty far apart, which could lead to inconsistent performance and feel. Another thing is that my suspicions were confirmed: Konis in full soft really are softer than OEM Sport package dampers. It also looks like I was right setting Konis about half way to full stiff to accomplish factory like feel and handling. One thing that's different about the dampers is the curves, as OEM Sport dampers ramp up quicker, and taper off. This means that OEM Sport dampers actually have pretty decent low speed damping, but not as good on the high speed stuff. Konis obviously have more room for adjustment, and they are perfectly matched as a pair on the axle.

 

[ReplicaR]

Well, first event is down. I decided to do both Saturday and Sunday, because I wanted some seat time to be able to maximize the car and the setup. A lot of unknowns were looming as the setup was very different to what I’ve ran in the past, not to mention that I didn’t know how I’d stack up against the competition. I saw that class would have a couple of M3s, one of them being a regional champion from last year, a 6th gen Camaro SS, 2001 Cobra, and Challenger Hellcat. I ended up taking 3rd place in the class, both of the M3s were faster by about 1.3 to 1.8 seconds.

In all honesty, this event was extremely humbling. Nothing like competing against some very fast people on a more or less levelled playing field that will expose your weaknesses, and really make you appreciate the finer details of car setup and driving technique. I have realized that I need to setup and turn in sooner than I do right now, which left me playing catchup game the whole time. One thing that I did improve on was the way I memorized the course. I used to walk the course before a couple of times, but then as soon as I’d get behind the wheel, I’d forget where I was supposed to go, which would reflect in slow lap times at the beginning. This time while walking the course, I recorded the whole thing on my phone, and then watched it several times after, till the point that I could replay it in my head with my eyes closed. I’ve also taken screen snapshots of corners that I would forget and then flip through them to make sure that I remember where to go.

Overall impressions are that I still need to finetune the setup further, if I want to move up closer to the faster guys in the field. The car has a bit of understeer, mostly due to the size of the front sway bar, which is a Hotchkis 35mm non adjustable sway bar. One of possible things that I will try is going to a smaller front bar, which would be a Eibach 32mm adjustable sway bar. I’ve received the specs on the sway bar rates from Eibach, still waiting on Hotchkis, which should be here soon. The dampers did an OK job trying to stabilize the car, but I’ve got a feeling that I need to work with them a little more, and possibly even revalve them to be stiffer in order to manage 3700 lbs car through the slaloms. The tires performed pretty well, considering the understeer issues and weight of the car as well. I can definitely tell that I was overdriving like crazy, just by looking at the front tires. The rear tires looked much better obviously.


Front Tires

Rear Tires

The video is available at the link below, this was my fastest run


https://youtu.be/P-L6NLyxmxc

 

[ReplicaR]

Further chassis tuning is coming. At the last event, I was fighting understeer most of the course. I believe that part of that was down to my driving (as it usually is), however the other part was due to the front sway bar I installed some time ago, which is probably too stiff for the rest of the setup. I needed a smaller front bar, so I called manufacturers, and tried to get concrete numbers. Only Hotchkis and Eibach were playing ball, Whiteline refused to disclose any information, and I didn't bother looking elsewhere. So, the figures:


OEM Sport Package (fixed)
Stiff: 107 Nm (960 lbs/inch) 100% stiffness


Eibach 32mm (adjustable)
Soft: 127 Nm (1124 lbs/inch) 117% stiffness
Stiff: 156 Nm (1380 lbs/inch) 144% stiffness


Hotchkis 35mm (fixed) - Currently Installed
Stiff: 220 Nm (1970 lbs/inch) 205% stiffness


Looking at those figures, I believe that Eibach in stiff setting might give me the balance I'm looking for with the current staggered setup. Hotchkis is a really good bar, but I think it would work better if I had same sized tires all around, which I can't due to class limitations. A full review and test coming in two weeks, when I will swap bar at the practice event and hopefully will optimize the car for Round 2 of competition.

 

[OLD H2S]

Arent those tires really soft, like 80?

 

[ReplicaR]

They are rated at 200 tw, but that's complete nonsense. They stick harder than NT01s which are rated at 100. They are basically fastest tire in the 200 tw range.

 

[OLD H2S]

My tire guy is scratching his head on how they get a 200 rating.

 

[ReplicaR]

Honestly, they are phenomenal tires so far. Grip like you would not believe, definitely faster than the rest of the 200 tw tires, although BFG Rival S 1.5 is supposed to be on par. You can usually tell what's a good class tire by checking the results of national events and see what people run. I want to say that last year RE71Rs were mostly the fastest choice, although there were some wins for Rival S as well. What cemented my choice really was the fact that Bridgestones are significantly cheaper than BF Goodrich in the same size. Seeing how I'm not sponsored by TireRack or anything like that, I have to keep that in mind.

 

[g36 monkey]

I may need to check into them, seeing as how I am not sponsored by anyone

 

[ReplicaR]

Great tire for track use. Would not recommend for daily driving, because they are super soft, so they will wear very quickly, and they are really loud.

 

[g36 monkey]

Great tire for track use. Would not recommend for daily driving, because they are super soft, so they will wear very quickly, and they are really loud.

I was thinking for track only. I appreciate your input bud!

 

[ReplicaR]

You're not a true G37 owner until I've blacked out some kind of chrome trim on your car. I've decided that I didn't like all the chrome trim on the car and decided to cover some of it up with either paint or vinyl. First step was to paint the grill and fog light bezels gloss black. Took them to a local shop, decided to leave the Infiniti badge chrome, and since it clips onto the grill, it was super simple to do. After that I took the car to a wrap shop, and they covered my chrome window trim with gloss black vinyl. The finished product is below. I really think that it came out rather well, especially the chrome trim around the windows. The trim had some water spots on the side anyway, so covering it was a simple decision.

 

[ReplicaR]

After missing a few rounds due to either being sick or away on vacation, I was finally back in action last weekend during Round 4 of SCCA SoCal regional championship. The field was much smaller than usual (100 cars instead of 150+), but I still had another car to compete in the class with me, which was a 2016 Camaro SS. I realistically know that at the moment I am not the pace setter, since this is just my second event, so if I were to win anything, this would be the best opportunity I would get all year. And that's exactly what I have done. My first class win.

The takeaway from this round of autoX:


1. The sway bar swap helped. I went form a really stiff Hotchkis 35mm bar to a softer Eibach 32mm bar in stiff setting, and it has paid off really well. I could feel immediately how much more traction there is in the front and and rear didn't feel too compromised either, so I feel that given the stagger of the wheels and tires, I've achieved the optimum balance for something that could be done with off the shelf parts.


2. Driving style improvements. I've asked an instructor to ride around with me, and one thing I worked on this weekend was turning in sooner. Much sooner than I thought I would have to. Learning how to do this helped me to keep the car more under control and increase the speed as I'm going through slalom, rather than play catch up with the cones and lose speed as I'm going through them. There is definitely still a lot to learn, but I'm truly excited about the progress I've made so far.


The video is below:


[video=youtube_share;6MtoRfpUBTo]https://youtu.be/6MtoRfpUBTo[/video]

 

[g36 monkey]

Congrats man!

 

[evilcw311]

That’s really awesome!!


Sent from my iPhone using Tapatalk

 

[OLD H2S]

Do you know the difference between the G37 and the M37?