No that's years down the road. Setup right now just has a ported Renesis that will stay NA. Hopefully that motor will last 3 or 4 seasons then when it lets go I'll be looking at putting a 20b in. If it needs a triple disc then I'll worry about that when the time comes, since a triple on a renesis that barely makes 150WTQ would be overkill.

 

Yes, but you don't just convert it to 3 disc. You will be buying another 3-disc clutch then. You also don't just size them by TQ rating, otherwise you only need a single 5.5 disc clutch. The more discs there are the lower the disc wear rate.

 

Yeah I'm already aware of all that. Now I'm just thinking maybe I should get a triple plate and be done with it and not have to worry about selling a very niche-market double plate clutch just to buy the triple plate version. I think the difference in cost between the double and triple is only 90 bucks so might as well do it now.

I've already gone overboard on a couple other things to try and make the transition to high horsepower easier so this will just be one more thing haha.




EDIT: Just got off the phone with Mazdatrix and I would be on my own as far as finding a suitable throwout bearing since the stack height is taller. Would most likely need to convert to a hydraulic unit.

On the other hand though, they said they have been running the 5.5" double plate in their 400+WHP time attack car for quite awhile now with no issues at all.

 

It has the same disc material you were planning to use?

 

He said it was the same unit that they sell (V-Drive) which I believe is sintered iron, so yes I believe it is the same material. They don't have an option for carbon/carbon on those, you can get those with one of their other lines of clutches called the Carbon-V. Yes I know you can probably swap the plates in before you say that as well.

I also finally found the torque capacity of their 5.5" V-Drive twin disc which is 600ft-lbs. Even with a 20b I won't even be at half that. Also the triple disc 5.5" V-Drive is 28% heavier and has 27% more MOI than the twin disc.

 

Nah... I'd buy it from you

 

Pretty sure you cannot just switch plates between the sintered metallic and the carbon styles. I'm more familiar with Tilton than QM. The main thing is you asked and researched it. It's a much different animal than the OE style clutch. If you were worried about only 28% weight/MOI you have a lot more than that over an equivalent carbon model.


.

 

Good point. I've also had to replace the tranmission once in this time period so it has recieved a new throw out bearing at least once.

 

Yeah I'm concerned about weight/moi but the limiting factor would be the phrase "within my budget" lol.

I also found the clutch on summit for 100 bucks cheaper. Will be going with the 5.5" twin disk V-drive, it should still do fine with more power later on and I don't have to worry about converting to a hydraulic throwout and it's cheaper and lighter.

Thanks everyone for your input, hopefully if anyone else goes this route with clutch setup these posts will help.

 

as long as you're using phrases like "within my budget" I think you should stay away from a 3-rotor aaron

 

Lol. Budgeting and not spending triple the money on parts you don't really need like carbon/carbon clutches is exactly how you save for a 20b!

 

touche'

 

True, true... but every ounce rotating at the same speed as the engine is an ounce worth removing, so just go ahead and save/make more money, Arca!

 

Got out to Gingerman this weekend with the new suspension setup - managed to drop down a 1:49.7 on Z1 star specs, which was my target to justify running NASA TT next year.

Current NASA TT Records @ Gingerman:
TTE: 1:47.2 (Kohler, Miata)
TTD: 1:45.5 (Cabot, FR-S)
TTC: 1:42.1 (Cabot, unofficial, S2000)

Car sits around 3300lbs with stock motor @ 28.3lb/min peak. I hope to reclass around TTE*/** with 190WHP and ~3200lbs (GT w/ big driver). From there, I would run 225 R6 with some room for A6, round out the powerband with an AP, and add aero if needed. Current mods (springs, shocks, sways, Z1SS) are +9. I'm betting on the hoosiers (NT01s were 2.5s faster than Z1SS on same setup) and -100 lbs from seat/battery/wheels to get me the 4s I need @ Gingerman.

The Koni Yellow/Road Magnet combo was 2.5s faster than the stock springs/shocks on the same tires, track, and driver. I had way more clean air on the old setup, I don't think it had anything left in it.

I left the DSC on and disconnected the rear bar for some fun in the rain on Saturday morning. I started the dry sessions with progress bars on hard front and rear. Grip increase from lower height and additional camber was instantly apparent and I was able to quickly pull off 1:51s, 1s faster than previous 1:52.2 on Z1SS (had run a 1:49.7 on 235 NT01s with same setup).

Car was noticeably looser and more upset by bumps but proved consistently quick despite being a bit of a handful on corner exit. The biggest problem was putting down the power on corner exit. A 2 psi drop in the rear tires and switching the RARB to soft helped settle the car a bit and got me down to 1:50s consistently and a 1:49 once I got in the groove. Still, it took a bit too much effort to drive and would be risky on a less 'safe' road course.

Morning session video:

Track is CW
Tire temps:
LF | RF
LR | RR
Across Tire:
158 158 169 | 157 124 107
137 151 154 | 156 143 125
Average:
162 | 129
147 | 141
Average F/R:
146
144
Average L/R
155 | 135
Cross:
LF/RR: 154
RF/LR : 138

Swapped the progress rear bar for the stock rear bar +0.75'' stiffer for the afternoon. Got the exact same lap time and the car was easier to drive. There was just a hair of understeer turning right and a little too much O/S turning left. Next mod will be adjustable perches so I can adjust the wedge. Rained later in the day so I only got a handful of laps over the whole weekend with clean air. I think some more seat time is good for another 0.5-1.0s as she sits, maybe more with the proper cross weight.

Afternoon video:

Tire temps:
Across Tire:
154 154 168 | 163 144 135
143 157 158 | 155 152 126
Average:
159 | 147
153 | 144
Average F/R:
153
149
Average L/R
156 | 146
Cross:
LF/RR: 152
RF/LR : 150

Final setup (slight U/S right, slight O/S left):
245/45/18 Z1 Star Specs
Hawk DTC-60
Catless Midpipe
Koni Yellow 3/4 Hard
Road Magnet Springs (330F/315R)
Progress Tech Front Bar Hard
Stock Rear Bar Hard
~13'' Ride height all corners
-3.1F/-2.4R Camber. 0 Toe.


-Chris

 

Nice! Thanks for sharing.

There are many ways to get to the same results; I have chosen to ignore aero (as in lift reduction/downforce generation) for now and focus on suspension and weight reduction/distribution; IMHO, there is much to be gained in these two areas with minimal NASA point impact.

Nice throttle management!

What was ambient temperature like? I see ECT around 206F; I suggest looking into cooling. Bigger radiator is an obvious answer, but there are different ways to get there too.

 

Nobody ever thinks they need something they never had before

Until they got it and then realized what they were missing

Just sayin' ....

After what you will spend on a proper 20B engine & conversion a $3.8k clutch/flywheel setup that you can depend on with your life is a drop in the bucket. I studied it long and hard, but given the current rulesets for the class choices I have it doesn't make any sense to choose a 20B over a 13B turbo. An NA 20B would still be an awesome thing to drive. I suppose it isn't always about what we think makes sense

 

owning an 8 is not logical at all, its all emotion and passion, why not continue this trend and go all out on a 20b swap?

only live once

 

I want very much to avoid aero because it looks funny on a street car and gets ripped up when you go off track. However, I have no intention of getting the car below 3200lbs w/ driver or increasing power to run TTD. Aero seems to make the most sense in lap time/$ and I think I'll have the points (and nothing to use them for) after a reclass. I estimate the aero benefit to be around 1-1.5s/min based on chatting with people that have similar power/weight levels and on lap sim results. I also have some decent experience designing/building aero packages. The tentative plan is to run w/o aero and only add it if necessary.

Yeah, shes set up to be neutral at maintenance throttle/constant speed. Had to be careful with the throttle to keep her pointed the right direction!

Ambient was around 50°F, she runs around 212-220 at 75-80°F. I shift at 9400-9500 on the tach, which doesn't help with heat. I believe it is faster to take her all the way out to redline based on the maf vs speed (power) curve and I have a lap time simulator that confirms that assumption with 0.5s shifts. It looks like there is more to be had from a higher rev limit even if the power is past its peak. I intend to go to 9600 true RPM when I get an AP. 225 17s should also help me stay out of second gear on all but the tightest corners. Radiator is ghetto-sealed with zip ties from the undertray to the lower part of the radiator. My first step would be to add some shrouding and then move the battery if necessary. I'm trying to minimize cost with the '8 because we're building a new chump car this year.

 

If the S2 water pump is like the S1's, your key issue is probably cavitation.

 

S2 pump was redesigned and should function more like the mazmart pump for the s1

 

Would a ~20% underdrive pulley on the WP prevent cavitation?

 

If you ever dyno your car you'll realize that shifting at 9500 is absolutely pointless and that you are putting less power to the ground by doing it and just creating excess heat and excess wear while going slower.These cars fall flat on their face at around 8500. It's simple math to calculate power under the curve through a certain gear.

 

On a different topic, Cobalt Friction has free shipping in October. I ordered and just received a XR1/XR4 set.

I've been on a XR2/XR5 set this year and I've been really happy with it; I still have plenty left.

 

Please see the attached graph. RPM are based on tire diameter and wheel speed. The tach reads about 4-500 RPM high at 9K.

Max values, 2nd to 3rd:
8.5K Shifts:
28.2 to 24.6 lb/min
9.0K Shifts:
27.5 to 25.7 lb/min

So, late shifting looses ~0.7 lb/min on the early gear and gains ~1.1 lb/min on the later gear. Not much, but it is something. You're right, I would need to do a dyno and integrate over the shift points to be sure.

 

Like I said, you'll see once you can get it on a dyno. The amount of air going through the maf doesn't have a fixed relationship with power output. Also you have to factor in time to the equation which is why these calculations don't scale to real results very well. You have to ask is it worth it to sit at over 9k for an eternity making no power or shift earlier where torque can get you out of a low power zone more quickly.