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So, a little background. I had a NA 300ZX in highschool that I autocrossed a bit. Come around college I bought a Twin Turbo 300ZX and autocrossed that in STU. Even though it was a good car and never left me on the side of the road, it really sucked up my wallet. It always needed something, after I fixed one sensor some bushings needed to be fixed, and this is one of those cars where if you fix one thing, you replace everything else you removed and is in the area (and I did that religiously). It is just the nature of it being a 25 year old car. The lag was horrendous at autocross and don't get me started on fuel economy. Picture of 300ZX:
So I sold it and bought a 350Z. (2006 Revup Touring)
Car is stock except for a JWT Popcharger that came with the car. First thing I did was get some tires, now the car came with tires that were in good condition but they didn't know what traction was (which was fun while it lasted) and the brand I never heard, Rotalla tires. What don't they make engine oil?
So I scored some barely used Dunlop Direzza ZII Star Specs in 245/40/18 to put on my OEM wheels (35th Anniversary), the tires still had the injection mold needles on them:
First event was this last weekend and I am extremely impressed with this chassis. The car felt tight and composed from the get go, didn't find any understeer and just a slight amount of oversteer that was easy to control. I came first in my class... out of one car. BUT I beat the cars in AS and BS along with some STX prepped FR-S' (Stock ones would've been in CS with me) So overall happy with results. Unfortunately my second sessions times were lost and they are trying to recover them now but should bump me up a bit higher but as of right now I am in 25th Raw and 17th PAX.
Have you checked out the NASA Spec Z seen out there? There are over 20 Spec Z cars it looks like. Might be fun to have a look.
I have actually, Lyfe Motorsports in SLC builds a lot of them. Spec Z is definitely out of my budget as of right now but its definitely something I want to do in the future.
As for HPDE events I'll try to get some under my belt, more likely to over summer rather than the middle of the semester.
Second event in this car is complete! Had a massive turn out of cars yesterday, 121 is a lot for the Utah region. I actually had competition this time in CS with 9 entries including myself. Majority were FRS/BRZ's another 350Z, a RX8 and a 2016 Miata being driven by a SCCA National Champ (That was daunting).
I held down 3rd place all day with the 2016 Miata sitting in first and an experienced FRS holding down second. I wasn't paying attention to times everyone else was getting towards the end but eventually the FRS beat the Miata and on my last run I shaved a second off my fastest after cooling off my tires, adjusting pressure and changing my line a bit. I ended up in second place being 0.1 seconds away from the time the FRS set at first place. I am happy I beat the 2016 Miata but also wanting more run time to see if I could have shaved some more time off and beat the FRS, there is always next time
Oh I actually have magnets now:
This was the fastest in the class next to me, I'll get him next time
I got a feel for how this car likes to push a bit at lower speeds. My tire temps at the front were very hot (hot to the touch) and I started to let air out after a few runs and felt a noticeable improvement in front end grip. At the higher speed slaloms the car didn't like being tossed around that quickly and tried to shake me off course. Reducing roll would be very beneficial!
Lastly, I realize why everyone dislikes the VLSD... a lot of times it felt like an open differential. That will go when I move up in class! Now I am curious of which ST class to move to. For classing experts, I know I can move to STU for a fact, what about STR? I have seen in the past other Z's in STR is that still allowed? I wonder because fastest in STU was at 48.5 and fastest in STR was at 49.5 seconds. Not sure if modifying the car to ST rules would warrant me a 4 second gain on a similar course. All though, it would be cool to be up there with the STU Evo that set that time, it was also the fastest of the day.
Awesome. Sounds like you're doing really well, especially being on Dunlops. Good to see magnetic numbers make an appearance.
It's kind of the nature of the car to push a bit at slow speeds. It's front-heavy and, well, heavy.
You can reduce roll and help combat inside wheelspin with a larger front sway bar and still stay in CS. If you find it pushes more with a big front bar, you can take out rear toe.
The 350Z used to be in STR. Like all cars in the class, it was restricted to 9" wide wheels and 255 tires. Brian Peters built one and won Nationals with it, then the 350Z got moved to STU, which allows unlimited wheel width and 285 tires. That's a better fit for the car, IMO. Brian won STU in the same car the next year, then sold the car to us. We are enjoying the fruits of his labor. And a lot more STU builds have come along since then, which is cool to see. It's a really engaging car to drive and not very expensive.
The 370Z is still in STR.
I used to autocross a Z32, too. NA, though. Built it for STX. Long ol' story behind that. Had a lot of fun with the build and the results. But, the call of the simpler, faster, more economical 350Z was strong.
Awesome. Sounds like you're doing really well, especially being on Dunlops. Good to see magnetic numbers make an appearance.
It's kind of the nature of the car to push a bit at slow speeds. It's front-heavy and, well, heavy.
You can reduce roll and help combat inside wheelspin with a larger front sway bar and still stay in CS. If you find it pushes more with a big front bar, you can take out rear toe.
The 350Z used to be in STR. Like all cars in the class, it was restricted to 9" wide wheels and 255 tires. Brian Peters built one and won Nationals with it, then the 350Z got moved to STU, which allows unlimited wheel width and 285 tires. That's a better fit for the car, IMO. Brian won STU in the same car the next year, then sold the car to us. We are enjoying the fruits of his labor. And a lot more STU builds have come along since then, which is cool to see. It's a really engaging car to drive and not very expensive.
The 370Z is still in STR.
I used to autocross a Z32, too. NA, though. Built it for STX. Long ol' story behind that. Had a lot of fun with the build and the results. But, the call of the simpler, faster, more economical 350Z was strong.
Yup I figured the front heavy nature of the car aided to low speed push, I used more throttle to rotate the car and tried cutting a line that required less steering input at lower speeds. I'll have to look into changing my front sway bar, I could see how that will help a lot. Thanks for that!
I'll still plan to move to STU, honestly I just liked the price of 255's better than 275/285's
And I remember your car! I religiously followed your build thread on 300ZX Club for when I began to set up my 300ZX. Funny to see we both moved to the 350Z for the same reason. Awesome!
And do you still autocross at El Toro? I'll be going back to my hometown for this coming summer break and that is the closest one to me (And San Diego SCCA, but to get there timely I need to drive through Highway 74)
You need to find the stock airbox fwiw....pop charger is not CS legal, strictly speaking.
As far as your driving...pretty good actually. I think you tend to be a bit too aggressive on corner entry and sacrifice on mid corner and exit. More time to be gained in those two sections IMO. As with everyone, you're a bit too off the cones, but that'll come with familiarity.
As a college kid, I'd stay CS....STU can get a bit spendy.
Last edited by 03threefiftyz; 03-22-2016 at 09:38 AM.
You need to find the stock airbox fwiw....pop charger is not CS legal, strictly speaking.
As far as your driving...pretty good actually. I think you tend to be a bit too aggressive on corner entry and sacrifice on mid corner and exit. More time to be gained in those two sections IMO. As with everyone, you're a bit too of the cones, but that'll come with familiarity.
As a college kid, I'd stay CS....STU can get a bit spendy.
I have my eye out for a stock '06 airbox. The JWT came with the car, it does sound good though. My region is pretty laid back with modifications, unless the JWT gave me a massive advantage, they don't care.
I appreciate driving feedback! Anything that will make me a better driver helps. I can see what you are talking about, I need more slow in, fast out. I'll keep this in mind going into my next event. Thanks!
Yea that would be best to keep it CS. I think I may save my pennies and convert my '06 Touring to the Grand Touring trim level. I spy a wrecked Grand Touring in a California junkyard, hopefully it is there when I go back home for the summer so I can grab everything I need.
I do get down to El Toro from time to time. I should be there for the ProSolo coming up next month. In summer, I may make a trip or two down there. Good group to autox with and the site is superb.
Nice driving. It took an autocross or two for me to adapt to the 350z. I was a little too greedy on the throttle and ended up doing a little too much drifting. The car seems to reward smooth drivers as opposed to aggressive ones.
Hey, we talked yesterday on IG. I'll be following you progress this season; driving looks quick and smooth, keep it up!
Hey I talked to you! I'll have to find your journal.
Originally Posted by eye-5
Nice driving. It took an autocross or two for me to adapt to the 350z. I was a little too greedy on the throttle and ended up doing a little too much drifting. The car seems to reward smooth drivers as opposed to aggressive ones.
Yea this car is super easy to slide. I like this chassis and power plant much better than my 300ZX TT.
How bad was the body roll after you added the Star Specs?
I agree with your observations after my two auto-x's with my stockish Z. The car is very easy to powerslide & control . I really need to replace my LCA bushings though .
How bad was the body roll after you added the Star Specs?
I agree with your observations after my two auto-x's with my stockish Z. The car is very easy to powerslide & control . I really need to replace my LCA bushings though .
So originally I had some cheapy knock off tire on the car called Rotalla. They would squeal before I got any body roll lol. When I put the ZII's on and did my first slalom, it felt like the side of the car wanted to leave the ground. Body roll is a bit excessive but a good coilover would cure it easily. For my class I am only allowed one sway bar change. I am going to see how that does for now.
A stiffer front sway bar will help with body roll. I would get an adjustable one if you can. Honestly, compared to other stock cars, the body roll is pretty minimal in the Z.
A stiffer front sway bar will help with body roll. I would get an adjustable one if you can. Honestly, compared to other stock cars, the body roll is pretty minimal in the Z.
Yea definitely not compared to others, I was exaggerating the difference and what I noticed with a sticky tire haha. My 300ZX made this look like nothing with body roll, and there was someone in HS with a stock EG civic and RE71's. That thing was hilarious to watch, got on two wheels once.
I'm considering the white line sway bars. Also trying to configure brakes. Debating if brembos are worth the money or if a good set of pads will be sufficient for autocross/ track use.
Also, had a question related to the mechanics (hydraulics maybe) of the car. When pushing the car and shifting quickly, when I let the clutch out the rpms bog down rather than instantaneously drop down. You can hear it in the shift from 1st=>2nd at 4:22 in the last video. Now it feels like the clutch pedal is sticking at the top of where the clutch grabs. (It feels like it doesn't follow my foot up all the way when I release). I am thinking it is the slave cylinder or the clutch. I did a clutch test my HS auto tech instructor showed me, drive at 20 MPH in 4th gear, rev engine up a bit, dump clutch. If RPM dies immediately clutch is good. Did that and RPM dies down immediately.
That and the way the pedal doesn't follow my foot up all the way (It gets stuck halfway up and eventually comes all the way up) has me thinking it is clutch slave that is bad. Also, I did flush the clutch fluid prior to this autocross event.
Does the pressure plate diaphragm struggle to keep pressure when getting hot or when the clutch is on its way out?
A stiffer front sway bar will help with body roll. I would get an adjustable one if you can. Honestly, compared to other stock cars, the body roll is pretty minimal in the Z.
Adding larger front sway bar makes a bigger difference than adding a larger rear on these cars?
Adding larger front sway bar makes a bigger difference than adding a larger rear on these cars?
I believe the logic behind it is the weight in the front (the motor) wants to shift side to side in corners creating a larger moment of inertia depending on which direction the car steers in. This creates more roll and puts more force on the leading tire. By having a sway bar tie together the front it reduces the roll and the moment created by the weight transfer helping keep the front end more composed.
A rear bar would create a tendency to rotate but wouldn't help with the front roll and understeer. So in some instance it would help but others it would oversteer or do nothing to help with understeer.
Also, had a question related to the mechanics (hydraulics maybe) of the car. When pushing the car and shifting quickly, when I let the clutch out the rpms bog down rather than instantaneously drop down. You can hear it in the shift from 1st=>2nd at 4:22 in the last video. Now it feels like the clutch pedal is sticking at the top of where the clutch grabs. (It feels like it doesn't follow my foot up all the way when I release). I am thinking it is the slave cylinder or the clutch. I did a clutch test my HS auto tech instructor showed me, drive at 20 MPH in 4th gear, rev engine up a bit, dump clutch. If RPM dies immediately clutch is good. Did that and RPM dies down immediately.
That and the way the pedal doesn't follow my foot up all the way (It gets stuck halfway up and eventually comes all the way up) has me thinking it is clutch slave that is bad. Also, I did flush the clutch fluid prior to this autocross event.
Does the pressure plate diaphragm struggle to keep pressure when getting hot or when the clutch is on its way out?
Interested in knowing about this because my car does it as well (although I just really noticed it recently). I would say at about 90% out is where mine seems to get a little sticky. But as you stated, it does return all the way out within half a second.
02-25-2016, 08:06 AM
350Z from CS to STU and NASA
And a lot more STU builds have come along since then, which is cool to see. It's a really engaging car to drive and not very expensive. 
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