CJM Fuel Starvation Control Product, Round 2

phunk

Yes I will have a couple different levels to choose from. We have always had the stage 0 kit and basic components like rails, twin pump, etc... then the road race pump. Now I am finishing the lineup for at least a stage 2 and 3 kit, and have made some changes to the rails and stuff.

Our fuel system kits are always complete.. The way CJM does it stages is easy:

Stage 0: This means no supply upgrade, just a return conversion for returnless cars.

Stage 1: Upgrades entire engine bay, and adds return conversion to returnless cars.

Stage 2: This is a stage 1 kit, plus all upgraded lines to/from the tank.

Stage 3: This is a stage 2 kit, plus integration of a multi-pump hanger... This involves slightly different plumbing at the rear of the car.

I know stages are sorta cheesy but its just an easy way for us to isolate the severity of the upgrade.

As I am finalizing these additional options, I am making my decisions on integrating the road race pump to the kits, which can simply be designated S2RR, and so on.

I have also been playing with the idea of a version where the road race pump completely eliminates the OEM sending unit, and takes its place. It was designed from the start to be something that I could turn into that... theres some pluses and some minus's of doing this, but I am theorizing ways to eliminate the minuses and it could result in a more simple setup inside the tank if it works. Its just that... how complicated do I really want to make all the options for you guys to have to choose from? I know that you want to learn and understand your fuel system, but I dont think you guys want to study for a month to decide which route you think is best for you. I need to settle on HP and application ratings for each combo to make the decisions clear as possible.

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phunk

If you choose to not hook up the fuel pressure regulator vacuum/boost reference line, and set the fuel pressure to stock, then the tune will not be effected at that time.

Anything over 10psi and I would recommend using the vacuum reference to keep your fuel pressure differential high. That means: If you have 52psi rail pressure, and 10psi of boost, you are effectively operating at 42psi fuel pressure. If you were 20psi boost, you are at 32psi effective pressure. So, once you start going nuts on the boost, you want your fuel pressure to climb with boost. Over 10 psi, hook up the regulator vacuum reference to a boost only pressure source. This would be a charge pipe before the throttle bodies. The VVEL system causes swings in manifold vacuum that are not consistently linear with engine load. Therefore, the manifold vacuum is not a direct indication of engine load, and therefore we do not want the fuel pressure regulator reacting to it. We want it to see boost only with VVEL. I am sure it would still work fine, but it is theoretically incorrect.

You can, if you choose, use the boost reference at any boost level you want. If you were say, trying to get the most of some undersized injectors, then you need all the help you can get, that few psi of fuel pressure which help.

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SPOHN

Very interested!!

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ENT-Z

^^ This!!!

Coyote

You can count me in.
I'll post a thread in the french forum and email a few friends.

mdxj

Finally hit fuel starve at the track today. Two really tight 180* right handers that I was able to pull 1g around. Half a tank and would start as soon as I tried to power out of it. Thankfully the car never fully cut out but i would loose all power for a few seconds. I will be ordering this sometime next year.

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'09 370 base - RIP
'09 370 Nismo - New track car

whis9

how much of an improvement is adding a return to returnless car, this is only a track car. the car is completely torn down, so I figure if it nets a good return I would add it now. maybe a stage 0 or 1

Thanks

SPOHN

A return system is only mostly necessary for higher horse power levels. Mostly around the area of 550whp+. So depending on your future mods of power will be what you need to purchase now or later.

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ENT-Z

Any more ideas on this setup Charles? This might be a nice idea for the FI guys like me who want to maintain use of a larger pump to feed the motor.

phunk

A return system will have no contribution towards resolving fuel starvation. The only basic thing that can help at all, is an upgraded fuel pump. By upgrading the fuel pump, even if the engine doesn't need it, will increase return volume (the stock system does have return fuel, its just happening inside the sending unit), which will increase pressure to the OEM transfer siphon, increasing it's ability to recover fuel from the driver side. This is more of a "in theory" sort of thing. In practice, I doubt it would be very noticeable if at all.

A return system is something I would recommend for any VHR car over 10psi of boost, or over 500-550rwhp. It doesn't seem to be needed below that from my own testing, although there are some cars at lower power than mine that I have heard reports of fuel pressure dropping. While my car is currently on the stock rails and return-less setup, there are a few feet of the fuel plumbing that is upgraded much larger... not because I thought I would need it, but because I wanted to reroute my fuel lines away from the turbos and manifolds. Larger aftermarket plumbing was built for this. This is the only reason that I can come up with right now why my car seems to be able to run a little more power than others without a return. Our soon to be released kits will include upgraded plumbing. Our basic Stage 0 (been available a couple years now) is just a return conversion and leaves the plumbing otherwise stock, and wont do anything to help flow, but will resolve the first signs of pressure drop from the stock fuel system.

But again, just to be clear, return systems alone will not help resolve fuel starvation in the 370z.

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phunk

I will begin work on this once the staged VHR fuel systems are completed in the next couple weeks. It will be good timing since that is when the Road Race Pumps will be going into the CNC. We will start from the bottom, working our way up... and the changes for what I will now refer to as the "standalone road race pump" will all take place at the top. I dont think it will be very difficult for me to develop the conversion, but I have my concerns about testing. Basically, it will need testing before I trust it. This would be best done in a non-turbo or non-supercharger car.. that way if there are any problems that cause a pressure drop, there is no risk of engine damage like there is in a boosted car. I think that testing might work best if I make the conversion parts and send them to an existing user of our road race pump with a non-boosted car who is interested in switching to this setup. They could leave all the in-tank hoses in there and everything so that if there is a problem with the new setup, its not a big chore to go back to the proven setup.

I think about this standalone version every night, and I fully intend to see it through. I dont know that I can make it exist before dead of winter or beginning of spring.

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phunk

In the next couple days I will post about how to move forward with our deposits.

I am very happy to see 14 people willing to commit, that is plenty for me to go forward with the next batch.

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phunk

BTW some more talk about the standalone version road race pump. This product would be a lot more costly and complex if it was required that I design it to work PnP with the OEM plumbing and returnless setup like the existing model does. I think that the extra cost of integrating an internal filter and regulator will probably almost match the cost of a return conversion anyway.

If I had the freedom to design the standalone version to only be compatible with our upcoming Stage 2 fuel system (or stage 3 in twin-pump configuration), it is something that I could get done much more quickly. Because it would require almost no changes to the road race sending unit itself.

So the most ideal candidate for a tester, would fit these circumstances:
A: Currently running our existing road race pump model.
B: Interested in upgrading to our Stage 2 fuel system (return conversion, billet rails, adjustable reg., upgraded lines, etc.) when available in a couple weeks.
C: Prepared for up to 10 days down time, to return the road race pump to us for a little reworking.

I would prefer the tester run it on the single 255 pump that is already in it, for initial testing. Integrating the secondary pump for a twin pump configuration would be an easy upgrade later.

I feel like I might have just described SPOHN perfectly Anyone else? There will be no cost for the changes to the road race pump. There would be a decent discount on the stage 2 kit for testing. The risk: it doesnt work well, and you have to put the road race pump back to how it was.

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martin82

Spohn! Lolll

Isamu

damn I wish i was a trust fund baby right now! lol

Phunk, I will be mssgin you here in the next couple of days.. I just got stateside and have alot of inprocessing to do, and after that my life will be some what normal

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黒子 ('Kuroko')
Project: SuperNova Owner/Operator and Lead designer @BlackGuard Aeroworks