Ad: Spool Helix HPFP overdrive Kit

[AzNdevil]

If you go back to my previous post there were discussed. Extreme rail pressure spikes that randomly occur no matter where you set target. We Spoke with Ken, and Justin about the issue, both had suggestions, none of them worked. A previously dead smooth LPFP signal is now extremely noisy indicating very real spikes/pulses in the inlet of the pump. The rail pressure spikes are causing trim issues. Have tried the trick of targeting 25MPA which is just above the sensor limit to flatline the signal and smooth everything out, this also did not fix the problem. Given enough time it may be fixable, but when we are on a deadline for an event it's easier to simply go back to what was working. Car was running perfectly, we changed nothing but added the overdrive, and we have not been able to run a full dyno pull since without misfires due to fueling problems. We can say the overdrive has no problem holding pressure to redline so it's doing its job but the spikes are posing problems on both rail, and LPFP signal.

there are shit tons of calculations done by the dme to control lpfp and hpfp vcv duty cycle
since the hpfp is overdriven and the result pressure isnt matching what the dme thinks it should see, it will freak out at some point and attempt to slow everything down

the fuel target tables available are more of a reference to what the dme more or less should run and not set in stone
can this be fixed? yes.. but it will take a lot of time to test the tabes available

i do have some ideas on what should be tested first but i am sure smarter people can chime in and give suggestions

 

[Chris@VargasTurboTech]

Is this going to be like that time the high lift cams were garbage and untunable but ended up being bad vanos solenoids or something?

I know you said the shotgun won't fit on this car now, but was it ever fitted and run? Shotgun and helix do the exact same thing so seems weird one would have tuning issues.

Not sure you read to the end where we clearly state the problem is probably fixable but when you are on a deadline for an event its easier to just go back to what was working. This car set numerous records with a shotgun and was the testbed for the shotgun when we first designed it. We never saw these issues. We agree with you, they do the same thing, but something is wonky, and we do not have time to sort it out before the event. Going back to what was working previously.

 

[SJ_1989]

Oscillation is what is causing this problem - my original post "a long piece of vibrating mass." Not understanding the problem, one might determine that a weak part that broke is the problem, and then one might suggest a billet mount to withstand the weight and stresses. And" thinking inside the box", as you say, one might not consider what that new billet mount is attached to, and how that may be the next weak link and crack (surprise surprise). Elementary experience, really. What's the next billet part to solve this problem?

It's the little things that often get overlooked that come back and bite. I fear the billet mount is only a temporary bandaid but we have no way of knowing for sure what the next weakest link is until it happens. The true fix needs to be a support from the stack to the block or wherever.

I mentioned my own concern awhile ago about the extra weight hanging on the end of the stack. So everyone can understand here's a SWAG at the impact to the overall mounting pump stack torque on the front of the engine by adding the Helix. This is only a static analysis so don't put much weight (pun intended) on the numbers. What counts here is I only changed the overall length of the Helix. There will be other loads that need to be considered like vibration, loads from hitting a bump, etc.

Key take away here is the HPFP is shifted farther away from the pump stack by the length of the Helix unit. This is directly proportional to the increase in torque. For example, take a 5 lb dumbbell and hold straight out in front of you. Easy right? Now take a 25 lb dumbbell and hold straight out in front of you.... Changing mass in that example instead of distance but same concept.

I provided equations so anyone can "plug and chug" if desired.

 

[NoQuarter]

there are shit tons of calculations done by the dme to control lpfp and hpfp vcv duty cycle
since the hpfp is overdriven and the result pressure isnt matching what the dme thinks it should see, it will freak out at some point and attempt to slow everything down

Agreed. And a major difference when compared to the shotgun is that the DME is driving an unaltered HPFP producing expected outputs to DME inputs (The second HPFP jumps in when needed). The Helix solution has an altered HPFP output from what the DME expects to see so will be fighting for proper control.

Try this: Set your computer mouse to maximum speed/sensitivity and attempt to follow a moving image on the screen. Going to be much more difficult for you to control that feedback loop.

 

[scrllock]

So, no failures with the billet pump casing then? Still don't have one, glad I've put this thing off forever now that more and problems keep cropping up, heh.

 

[Chris@VargasTurboTech]

Just an update, Tony made some custom hardware changes to the rail and a couple of other things and was able to get rail pressure a little more stable.

Ps. https://vargasturbo.com/installation-instructions-product-documentation/

Might be a treat in there for you guys if you look hard enough

Chris

 

[The Convert]

Just an update, Tony made some custom hardware changes to the rail and a couple of other things and was able to get rail pressure a little more stable.

Ps. https://vargasturbo.com/installation-instructions-product-documentation/

Might be a treat in there for you guys if you look hard enough

Chris

We’re the rail and other things stock before when he was getting the pressure spikes? I know he had made modification to a bunch of that stuff in the past.

 

[Chris@VargasTurboTech]

We’re the rail and other things stock before when he was getting the pressure spikes? I know he had made modification to a bunch of that stuff in the past.

The rail was not stock. The same rail we ran with the SB previously. Either way it's working ok, still pulses on the LPFP signal, but we can live with that for now.

 

[Torgus]

Has anyone on this platform ever used a fuel pump dampeners? They make them for both HPFPs and LPFPs. Seems like that would be a place to start as they are designed to absorbs the fuel pulsation of the fuel pumps, reduce noise, and prevent instantaneous pressure drops. Which it sounds like are all the issues people are experiencing.

I have an idea as to the fix just from reading that document. I know where I would start at least assuming I didn't want to install any dampeners.

 

[martymil]

I've been using one for over a year and it works quite nicely, settles the lpfp pulses right down and helps with hpfp too.

 

[DR-JEKL]

One of the guys in Oz had a 3x kit with billet plate fitted and after 2 weeks cracked his vac pump housing.

As much as Marty can be annoying he was correct, the car in question had lost brake assist and had become difficult to drive in traffic (thankfully occured at low speeds)

Spool got back to him with the following info:

We did some simulation on our end and it seems bolting the assembly onto the block prevents any kind of torquing or canterlever stress issues.

We did some failure analysis and seems like gyroscopic forces generated from the 4x was cracking the vac plates that probably had some imperfections from factory casting process.

We’re developing a bracket to solve this as we speak. This is the first time we’ve seen a 3x crack a vac pump. We’ve had two testers of the 4x with the issue recently.

So kudos to spool for the informative response and will offer to send the bracket out soon.

 

[fmorelli]

Kudos to Spool for being all over this. And I am not surprised that their testing showed what I predicted when the first failure was reported - that "gyroscopic forces" are in play. That's why a bracket is the solution. As for "casting imperfections" - that is the inherent nature of casting. Emus unite!

Filippo

p.s. Good work on Spool's part. While alpha and beta testing is great ... and these guys did it ... there is unfortunately no substitute for at-scale testing. Sampling only gets one so far, unfortunately ... and no manufacture can escape that reality. Including BMW.

 

[martymil]

Harmonic vibrations are a metal killer and it doesn't matter how strong the metal is as eventually it will crack.

As you can see in the pic above this crack is not caused by gyroscopic forces but purely from vibration period.

Transferring those vibration into the block is a terrible idea and putting a knee jerk quick band aid fix is only delaying the inevitable.

When we build motors we balance and blueprint them to reduce vibrations as they lead to premature failure of components and blocks.

Now your introducing more vibrations into a thin alloy block and as rpm increase so do the vibrations.

In the end of the day the pump is the culprit that causes the vibrations and this is what needs to be addressed to solve the issue and this kit is
not the only kit that suffers from the issue.

 

[fmorelli]

Rubber bushing.

 

[V8bait]

Rubber bushing.

Red poly bushing, for performance.

 

[martymil]

A clamp lined with rubber around the drive bolted to the block if you must would possibly work.

 

[martymil]

For ilustration purposes only and its only an idea.

Black is the over drive, orange is the pump and red is a ring around the pump filled with rubber to stop vibration transfer and support the pump of the block if you must.

 

[The Convert]

Harmonic vibrations are a metal killer and it doesn't matter how strong the metal is as eventually it will crack.

As you can see in the pic above this crack is not caused by gyroscopic forces but purely from vibration period.

Transferring those vibration into the block is a terrible idea and putting a knee jerk quick band aid fix is only delaying the inevitable.

When we build motors we balance and blueprint them to reduce vibrations as they lead to premature failure of components and blocks.

Now your introducing more vibrations into a thin alloy block and as rpm increase so do the vibrations.

In the end of the day the pump is the culprit that causes the vibrations and this is what needs to be addressed to solve the issue and this kit is
not the only kit that suffers from the issue.

Your quip about all metal failing from harmonic vibrations is patently false. Parts failing from vibrations fail due to a combination of the material properties, physical design of the part, the natural resonant frequencies of that particular design, and the frequency the part operates in when in use. Every part and material has frequencies it will last forever in and ones it will fail early in.

 

[martymil]

We are talking about in this case and all the forces in play or do I need to spell it out every time

Is wasn't that long ago that you where riding the praise the Lord bandwagon when I was crtisising the shotgun kit until he fixed it.

I suggested an idea to fix the problem as the current bracket looks like a bandaid from what has been proposed.

I'd love for this product to work as I stated this its needed but it needs to be done properly.

I have customers ligning out the door for this but they are waiting to see how this product matures.

 

[The Convert]

We are talking about in this case and all the forces in play or do I need to spell it out every time

Is wasn't that long ago that you where riding the praise the Lord bandwagon when I was crtisising the shotgun kit until he fixed it.

I suggested an idea to fix the problem as the current bracket looks like a bandaid from what has been proposed.

I'd love for this product to work as I stated this its needed but it needs to be done properly.

I have customers ligning out the door for this but they are waiting to see how this product matures.

If you think I was in the leg humping group, you’re sorely mistaken. I don’t and won’t buy products built for this platform anymore without serious testing and tons of happy customers over prolonged periods of time because most products for this platform might as well be Kickstarter projects. I’d love for whatever needs to happen to happen for this product to be successful as well, but you can’t go painting thin lines with a broad brush and expect not to get called out.