Odd question: CJM RRP vs 2 piece brake rotors

Shoeshear

Dumb question, that I think I know the answer to, but here goes. Been running 300TW street tires for the last few years. Got a set of track wheels and going to be moving to Hankook RS4 285 square. I just added brake cooling ducts, but I have boiled the brake fluid at the track before.

The question:

My wife has approved a new purchase and I have been reading that with this step up in tire (also just installed suspension goodies), I’m going to run into fuel starve. I have not yet run into fuel starve (I always track with minimum 1/2-3/4 tank), but I’m considering picking up the CJM RRP.

Alternatively, I’m also considering picking up the Z1 2 piece rotors for a bit of weight reduction and and maybe a little less brake fade (???).

I’m guessing the answer will be to go with the RRP, but I wasn’t 100% sure as I haven’t yet encountered fuel starve.

Brief car specs and goals:
HPDE mostly for now, and eventually NASA TT or road racing (guessing ST3). Car still is street driven on occasion, but I usually daily my motorcycle. Will probably be doing 3-5k miles per year in the car (work is going to be a long drive).

Wheels/tires: Enkei RS05RR 18x10.5 square with 285 Hankook RS4 all around
Suspension: FA500 coilovers true type 12k front 8k rear
Alignment: -2.5 front camber, +6.x caster, a little toe in. Rear is -2 camber and .12” total toe in (too much IMO, will be getting realigned).

Reference lap time: running about a 1:50 or maybe high 1:49 at laguna seca and 1:09 on Bondurant/Firebird/Wildhorse West CW. All on ContiExtremeContactSport 255 F and 285 rear and stock suspension.


Does the collective think l will run into fuel starve with my step up? Thanks in advance.

street2soul

It doesn't take a lot for 370Z to have fuel starve on sustained right hand turns like a carousel or a long sweeping right

I had fuel starve with Continental DWS06 which is 560TW and they're not a lot of grip. My first ever track day was with S-04 pole position and it happend on my 2nd session. Had no idea what it was. I'm guessing with 300TW, It will happen if you have something like less than 60-65% tank. It gets worse with gripper tires like the 200TW or R compounds which you will get fuel starve after 3-5 hot laps

Shoeshear

Yeah fuel starve in 3-5 laps will be no fun. I guess part of me was a bit skeptical at starvation potential, but I think I’ll just commit to it.

cv129

RRP by a mile, not even close. Very marginal benefit vs transformational change in running time. Not very hard have fuel starve. Upgrade the top hat while you are at it.

Is plunk making a batch run on the RRP right now?

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Shoeshear

I don’t think phunk is doing a batch run right now. Was planning to ping him to see what the plans were on it. I had remembered seeing that it was planning to be offered as a standing product, but I can’t seem to find it.

OptionZero

He is working on a new design for an RPP v2 but its not ready yet
fuel starve solutions

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SeeThruHead

it would be really nice if they offered a surge canister for the cjm top hat. For those who don't need more than stock fuel flow, and just surge protection. Would have a bunch of money.

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Shoeshear

Damn, I’m definitely going to wait for V2 then… I’m definitely in the same boat regarding flow. I’m not planning to run much over stock power for a while, and will not be going FI. Just don’t want to deal with the fuel starve. After a few years, will probably be planning to build a Miata or a corvette for road racing only, depending on my geography and life needs/finances at that time.

@OptionZero thanks for the link. Missed it when searching earlier.

BettyZ

Order the surge canister. Line it up with the CJM tip hat and drill the aluminum so you can bolt it on.

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BettyZ

Investing in fuel now is a good choice. Everyone that swears they're not going FI ends up going FI, or totaling their Z before they have the chance to go FI.

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Shoeshear

Is the surge canister + top hat modification close enough to the RRP setup? It seemed like there was more than just the surge canister in the RRP kit. And also, the reason I’m trying to avoid boost is because I just want to get a lot of seat time at the track in the Z. If I keep it nice and stock, I should be able to get more laps/$. But appreciate you looking out nonetheless.

DarkJak

I agree, a fuel starve solution is great to have early on. The earlier the better, IMO, because if you end up having to pay for gas at the track, that's probably $50 extra in fuel costs each day. Or if you have to pit in early because you fuel starve halfway through a session, that's a considerable amount of track time you paid for that you now are missing out on.
It saves buying a couple more fuel jugs to haul gas to the track, if you DO plan on bringing extra fuel.

And that's a quality of life improvement you'll run into early on, and one that slowly pays for itself over time.

2 piece rotors are much less noticeable in comparison. You are unlikely to require the extra cooling they provide for a while, and the difference in feel from the weight reduction won't make or break a day out. Once you're fading track pads, or close to boiling fluid, it'd make more sense to swap, but for a lot of people and tracks, good pads and fluid are all they need with stock Akebonos.


Waiting for CJM is nice if you have the time. If not, Radium's in tank surge tank kit also works well, though not a beautifully designed and machined as CJ's. Another solution that works well enough is the Z1 kit, though it won't let you run as low as either surge tank solution. It's just a second pump that draws through a fuel mat and feeds into the OEM pump's basket, and not a surge tank design.

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OptionZero

Radium was sadly out of stock for a while

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2011 Nismo#91

RRP! I have almost ran the tank dry and no fuel starve because I forgot to fill up before that session. On the track the gauge read no fuel but off the track it went up to 1/4 or so.

Surprised that your brake fluid boiled, I never boiled fresh RBF600 and my pads were literally smoking. IMO 2 Piece rotors are over kill for beginners and intermediate groups. With the basics done I would focused on safety gear. Shoes and gloves for yourself and seats and harness bar or better for the car. And that safety gear will carry over into racing too.

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Shoeshear

I got very light fade at the end of the 20 minute sessions with project Mu pads, and essentially none with CT XP8 which is what I'm running now. I did manage to boil the fluid though, but after a full flush, haven't had it boil again. I haven't gotten the chance to run with 200TW tires and the brake ducts yet, but hopefully that will fend off any fade or fluid boiling issues.

I have been looking at the radium "kit" over the weekend, but it seems much less self-contained than phunk's RRP and somehow they made the install seem more complicated thank what I've read up on the RRP. Not sure what's going on there.

I think I'm going to skip the Z1 hydramat option. The collective knowledge seems to indicate that going with some kind of surge-tank design is the move.




I haven't been running RBF because it's still a sort of daily driven car (less and less with each passing week) and I didn't want to deal with the more frequent bleeds since it absorbs a bit more water than the standard fluid.

Other than being a bit less shiny, any thoughts from any of you on the Radium unit? Does it work as well? My next few months are looking like absolute shite (back to working 80-100hrs/week), so I feel like it's probably worth waiting for phunk to bring some goodies to the table (phunk if you read this, pretty please???).