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wydopnthrtl · Posted: Thu Jul 14, 2005 1:42 pm Post subject: Fuel pressure spikes?

I'm still a newbie but I did do a search and could'nt find an answer.

I'll have the WON/pulsiod system hooked to my fuel rail that supplies all 8 injectors. And my tuner says I'm good to go as far as fuel pumps/supply for a 100hp shot.

My question is:
When these things pulse, what happens to the output of my regular fuel injectors?

Seems to me since they are on the same circut, there is nothing to buffer the pressure differances that the injectors will see. At the 100hp and under level is this a non issue? What say you guru's of nitrous?

Rich
_________________
2002 Ford F150 Lightning
11.70@115mph
Thanks to REM & Racetested
&
2001 Cadillac Eldorado 13.95@101mph
Thanks to Racetested

racetested · Moderator Joined: 03 Feb 2005 Posts: 2104

I'm not sure if I understand the question properly but I'll give it a try. Since nitrous is used at WOT your fuel pressure will be at max pressure. If there is a drop from what your max fuel pressure should be then you need a higher flowing system. The pulsing of the fuel solenoid should not affect your factory injectors as the inlet pressure should be the same and it's the outlet of the fuel solenoid that is controlled by pulsing.

wydopnthrtl · Posted: Thu Jul 14, 2005 5:44 pm Post subject:

I understand.

The 8 fuel injectors in thier designed state have no fluid pressure spikes. Or at least none from an unvalidated source in the OEM fuel system.

I understand how the pulsoids work and it seems to me they will now have the effect of adding a pressure differancial that was not there before. Wether it's low pressure or high pressure I don't know?

Don't get me wrong.. I have'nt used the system yet and have never heard of any issues. I'm just asking the question if anybody has seen something related to this pressure differance and how it effects a motor with electronic fuel injectors.

My goal in this post is to look for possible areas that could effect A/F ratio. Some injectors will flutter or stop if exposed to a high enough pressure.

In case you don't know.. I'm a OEM automotive engineer with 6+ yrs of fluid handling experience. And many other areas as well. I tend to beat details to death... Red Face

Rich
_________________
2002 Ford F150 Lightning
11.70@115mph
Thanks to REM & Racetested
&
2001 Cadillac Eldorado 13.95@101mph
Thanks to Racetested

Loopy · Guest

The short answer is it doesn't bother them
(I take as much from my nitrous as the injectors themselves so it should be a massive spike)

Now ther's two answers, depending on the system, and don't take them as absolute gospel because i've seen some really weird systems that don't obey the rules.

End of rail regulated with return to tank;
*Run maximum pump speed
*Use a fuel take off manifold with a CSA of at least double the supply pipe ID to minimise the disruption / turbulance effect on the remaining fuel.
*Keep the rail to regulator distance as short and direct as possible, direct mount if possible.
*Adding an accumalator to this system will tend to give you a smaller negative spike, but a larger and more prolonged positive spike.
*Going progressive will usually minimise this effect

Tank regulated with no return;
*Run maximum pump speed BEFORE WOT
*Keep all pipe work as expansion free as possible
*Again use a fuel take off manifold with a CSA of at least double the supply pipe, but be careful not to generate any expansion anywhere.
*I don't like taking the fuel from the end of the rail.
*This system really doesn't like accumalators, keep the whole thing as expansion free as possible. I don't even like braided pipe. I prefer hardline pipe as far as possible with flexi links only.
*This system will tend to give you a negative spike only
*Progressive has little effect, maybe lessens it a little.

But like i said in my short answer, we tend to take 50% of our flow for the nitrous and we simply don't have spike problems of any real magnitude, certainly nothing that bothers the main injectors.

Keep your pump speed high, keep your lines free flowing and don't add expansion.

wydopnthrtl · Posted: Thu Jul 14, 2005 8:33 pm Post subject:

Thank you! And it sounds good enough for me with my little 75-100 shot.

Regards, Rich
_________________
2002 Ford F150 Lightning
11.70@115mph
Thanks to REM & Racetested
&
2001 Cadillac Eldorado 13.95@101mph
Thanks to Racetested

Loopy · Guest

Were you waiting for that or something ?
It gave me a heart attack seeing a response so fast Laughing

Noswizard · Posted: Thu Jul 14, 2005 8:50 pm Post subject:

Whilst I have no experimental evidence to prove it either way, there seems to be no problems from pulsing the system, however the lack of pulsing in our new (soon to be released - 6 to 9 months) Smooooth system will be one of the advantages over existing pulsed systems. Wink

Regards
_________________
Trev (The WIZARD of NOS)

wydopnthrtl · Posted: Fri Jul 15, 2005 11:53 am Post subject:

Thanks Guys!
The "Smooooth system" (I saw the vid) sure seems to be quite innovative. The idea of having it vary with my throttle position sensor sure appeals to me. It would take the trial and error out of tuning at the strip.

Rich
_________________
2002 Ford F150 Lightning
11.70@115mph
Thanks to REM & Racetested
&
2001 Cadillac Eldorado 13.95@101mph
Thanks to Racetested

Noswizard · Posted: Fri Jul 15, 2005 12:09 pm Post subject:

There are numerous advantages and we're busy working on further advances in design etc. so keep in touch if you want to keep with the most advanced and best quality products on the world market. Wink

Regards
_________________
Trev (The WIZARD of NOS)

wydopnthrtl · Posted: Fri Jul 15, 2005 12:22 pm Post subject:

I take it Trev that this would get rid of the pulsoids? One thing I'm after is stealth. I want the hood open for cool off at the track, and the large brightly colored pulsoids kinda draw peoples eye if-ya-know-what-I-mean. Wink

Rich
_________________
2002 Ford F150 Lightning
11.70@115mph
Thanks to REM & Racetested
&
2001 Cadillac Eldorado 13.95@101mph
Thanks to Racetested

Noswizard · Posted: Fri Jul 15, 2005 12:48 pm Post subject:

We now offer them in black if that would help. Wink

The new system still uses the Pulsoids but "modified and with some extras" Idea

Regards
_________________
Trev (The WIZARD of NOS)

wydopnthrtl · Posted: Fri Jul 15, 2005 2:52 pm Post subject:

Hum... ok will the pulsoids be any bigger than the current ones?
Reason I ask is because I'm planning on mounting mine this weekend. l'm looking to do something to hide them from the casual observer.

Rich
_________________
2002 Ford F150 Lightning
11.70@115mph
Thanks to REM & Racetested
&
2001 Cadillac Eldorado 13.95@101mph
Thanks to Racetested

racetested · Moderator Joined: 03 Feb 2005 Posts: 2104

The pulsoids are so nice looking, why would you want to hide them? :mrgreen:

A little tip is to pull off the sticker as they come off easy and let the nice anodizing shine by it's own.

Noswizard · Posted: Fri Jul 15, 2005 5:38 pm Post subject:

They are the same size but with some extra bits. Don't worry about the new system just yet as we're a good few months away from even offering them to our race customers so it could be a year before they are available for street applications. Wink

So enjoy what you have for now and if you want the new system once we have them finished we'll sort out an upgrade for you then.

Regards
_________________
Trev (The WIZARD of NOS)

wydopnthrtl · Posted: Fri Jul 15, 2005 5:41 pm Post subject:

Thanks Trev.

Rich
_________________
2002 Ford F150 Lightning
11.70@115mph
Thanks to REM & Racetested
&
2001 Cadillac Eldorado 13.95@101mph
Thanks to Racetested

racetested · Moderator Joined: 03 Feb 2005 Posts: 2104

I'm to blame on the confusion. Initially the smooth progressive was going to be much smaller and we started talking about it to early. Many changes have been made since then for copy security reasons and to utilize the existing solenoid bodies that are currently available.

wydopnthrtl · Posted: Fri Jul 15, 2005 5:52 pm Post subject:

I'm not prying about your designs. I'm just considering making a fiberglass cover that will be able to cover my current setup & the next gen stuff.
Have'nt put much thought into it yet though. I don't want it to retain heat.. yet I want it to look like something that came from the factory.

Rich
_________________
2002 Ford F150 Lightning
11.70@115mph
Thanks to REM & Racetested
&
2001 Cadillac Eldorado 13.95@101mph
Thanks to Racetested

Noswizard · Posted: Fri Jul 15, 2005 6:47 pm Post subject:

If you want the box to do for the Smooooth system then make it about 1" wider than the current width of a pair of Pulsoids and about an inch taller. However as we haven't yet settled on the "exact" design to market yet, I can't say for sure what we will end up offering at this stage.

Regards
_________________
Trev (The WIZARD of NOS)

wydopnthrtl · Posted: Fri Jul 15, 2005 8:08 pm Post subject:

Thank Trev!

Rich
_________________
2002 Ford F150 Lightning
11.70@115mph
Thanks to REM & Racetested
&
2001 Cadillac Eldorado 13.95@101mph
Thanks to Racetested

Jack B · Teacher Joined: 28 Feb 2005 Posts: 75

I have done some fuel pressure logging. The system type is the latter described by Loopy. The pump always runs full speed with an internal regulator. The fuel pressure will show transient spikes during changes in power/flow. These will not affect the effective flow to the injectors, however, as you approach the maximum pump output the spikes will get more pronounced and eventually affect fuel flow to the injectors and solenoids.

In summary you will not have problems until you get close to your pump capacity. It is fairly easy to match hp to fuel pump, take a look at the Kenne Bell web site, it has a lot of good fuel system data.

wydopnthrtl · Posted: Sun Jul 17, 2005 11:49 am Post subject:

The KB site huh? I'll give it some investigation.

Rich
_________________
2002 Ford F150 Lightning
11.70@115mph
Thanks to REM & Racetested
&
2001 Cadillac Eldorado 13.95@101mph
Thanks to Racetested

racetested · Moderator Joined: 03 Feb 2005 Posts: 2104

To funny as KB is well know for their Lightning blowers and I would have thought you looked at their site in the past Rich. Smile

wydopnthrtl · Posted: Mon Jul 18, 2005 11:46 am Post subject:

I've scanned it before. But never really dug that deep into thier posted info. Red Face

Rich
_________________
2002 Ford F150 Lightning
11.70@115mph
Thanks to REM & Racetested
&
2001 Cadillac Eldorado 13.95@101mph
Thanks to Racetested

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