okay need someone who knows nitrious really well. 540 cu in motor can i safely run a plate system at 150 shot with a 140 gal pr hr electric that pushes 18psi. i run the motor at 9 pounds already . can i tee off my regulator and use only the one pump safely? for only a 150 shot . :confused: decided to try some juice wich im opposed to since im old school where the motto run what ya built and hope you built enough apply,s . but hey gotta try something new sometimes.. have a 647 lift roller 10.4.1 compression 4.10 gears 3800 sthal .

you can...but I would atleast run a hobbs switch on the N20 side. I used to run a simular set up. I Tee'd the main line to two regulators, one to the carb and one to the N20. I have since went to a dedicated pump for the N20

so it would be best to get a second pump.? for the nos.

Or one good single pump. If you can afford the 540 you can afford a good pump!

www.productengr.com (http://www.productengr.com) try the 310 pump PE4500. Rated for continuous duty (BG and others aren't), it's $349 less what you can sell yours for, and it's good for 900hp (they are conservative.) If you know you are going to step up to more power later, just buy the 460 pump. I have used one for street strip for 4 years (short seasons) now no problems.

It also has a warranty for 2 years!

And no, I am not paid for this endorsement, or do I even get sponsorship or a deal! I tried!

wow its like that a professional race pump im a pro tour hot rodder type you really think i need that much fuel pump for a 700 plus horse engine and a 150 shot of juice?.

Doesn't matter where you drive it - it's how much power you plan to make. You can add another small pump but that's just another thing that can go wrong.

This pump would be more than adequate for what you are doing and it is not realy expensive in the scheme of things. What can you sell your pump for? My pet peeve is when people try to do too much with a holley blue for example and then can't explain why it pops or won't MPH.

I agree with 66 283, get one big pump to do the job and definatly run a hobbs switch. IMO, the pump you are currently running is barley enough to keep up with your motor.

BTW, after you spray it the first time you'll never look back.

good luck

okay so ill take the advice and ditch the 140 gph pump the price isnt an issue do they also provide a regulator for that pump since it surpasses my current regulator?

not quite sure what a hobbs switch is ?

The cheapest way (and it will work just as good). Run a -8 line to the front to a moroso Y block - run 2 12-803 cheapie holley regulators, one for the carb, one for the nitrous. The regulators work great - they are on almost every nitrous promod so they must be ok. That's probably the regulator you already have so another $25 and you have a second for the nitrous.

The pump has a high pressure bypass return that must go back to the tank.

If you set flowing fuel pressure on the nitrous system ditch the hobbs switch. I don't like them - they do more damage and cause more problems than good.

agreed a hobbs switch can be a pain...but until you have a good understanding of your fuel system and N20 tune up..use the hobbs switch(minimum fuel pressure switch)

for a regulator i have aeromotive says not to excede 20 psi its from 5-20 psi adjustable wouldnt i need a regulator that will take the pressure that the pump output,s? of 25-28 preset psi?

That is the set point of 20. You are not going to be setting either your bowls or your nitrous at 20psi - 25-28 is on the inlet side of the regulator - no problem.

Call Product Engineering and ask for John - he is very helpful and he will explain things to you - but don't let him tell you that his regulators are necessary. I bought them, they are very nice, but they are NOT necessary. The cheap stuff works just as good!

Hobbs switches are for people that are too lazy to check flowing fuel press. on a regular basis LOL with nitrous there is no room to be lazy!

ok will do thanks have the pump ordered already

You won't be disappointed! I promise. His pumps kick butt and he provides great service. Shoot me an email if you have any more plumbing questions.

He's in your state too so if you need help he's close.

I have his 460 combo pump and I am going to send it to him for upgrade to EFI dual stage pump. (add another motor to it)

ok will do thanks for the info and the hook up on the pump..

Originally posted by 66 283:

Hobbs switches are for people that are too lazy to check flowing fuel press. on a regular basis LOL with nitrous there is no room to be lazy! Man thats harsh....when I first started to run N20 thank god I used a hobbs switch. I used led indicator lights in the cab to tell when the Hobbs switched opened and when the solinoids opened. It took me a while to get it dialed in...but im sure the hobbs switched saved my bacon a few times. and believe me im not lazy.. Watch your timing close eeven with a 150 shot..learn to read your plugs for detonation and lean. I pushed the ring lands off because I didn't interpert the plugs correctly

aye reading plugs im no stranger to after talking to glen this evening of rex hutchinson racing engines im just gonna plumb in the 150 shot through the manifold bosses he claims there,s nothin like a fogger and its easier to keep in check so he is gonna give me a break and do all the plumbing work for 150 bucks and it will be all set for a 150 shot and he says i can run the fuel side a tad rich until i get the idea .. not lookin forward to tearing the intake back off just after gettin it fired up but hey if im gonna have fun i might as wel have all i can right.?

66 283,

your quote

Hobbs switches are for people that are too lazy to check flowing fuel press. on a regular basis LOL with nitrous there is no room to be lazy!

this is the worst advice you could give to a guy/person using nitrous for the first time.

A hobbs switch can be bought from summit for $36 ( how much did you spend on your engine) it's a simple device that's made to shut the nitrous off if the fuel pressure drops off for any reason. It's just safe insurance. For example, lets say you set your flowing fuel pressure at 5.5LBS, then you set it to 5lbs , then you adjust the hobbs switch so it shuts off the solenoids, now turn the regulator fuel pressure back up to 5.5 lbs and you have your safety margin built in.

If you don't know how to set flowing fuel pressure - you can't use a hobbs switch. In my experience 95% of the people out there who wired up their hobbs switch thinking they are safe don't have a clue what their FFP is nor do they actually adjust the hobbs. They think by virtue of having it plumbed and wired they are "safe."

When the hobbs does it's "job" it turns the nitrous on and off quickly if the fuel pressure hovers around this set point - which is hard on things and can cause a nitrous backfire!

The most common scenario is that it is set too close to the FFP and when you launch and the nitrous comes on - the pressure drops for an instant as the regulator catches up - followed by popping as the hobbs turns the nitrous on and off.

2 separate reasons fuel pressure would be too low:
1)you set it too low to begin with -> if that is the case and you set it there on purpose and set your hobbs switch below that FFP - you will still make damage
2)your fuel pressure dropped. If your fuel system is so underdesigned that the pressure drops every time you hit the nitrous or go down the track - you will eventually hurt it with or without the hobbs switch. Pressure does not equal volume! Also, you will know in the driver's seat if the pressure drops that suddenly.

The best answer is to not run a hobbs, make sure to run fuel and nitrous filters, and that you set and check your FFP regularly. I have never lost fuel pressure during a run - and I check it afterwards also and the FFP creeps very little day to day but you still need to check it.

I agree with that, that's why i tried to instruct him on setting fuel pressure and also setting the hobbs switch. I just feel it's a nice safety feature for a beginner. But they do need to be set and tested that it will shut off the solenoid.

Mike

If you talk to any of the nitrous gurus who do it for a living - most will say "throw that hobbs away."

once again your talking about experienced people. I'm referring to the origional poster who's never run nitrous before. I personally see nothing wrong with having a safety device hooked up. Lets say you set flowing pressure at 5.5 lBS and have the hobbs set to shut the system down at 4.5 lbs flowing pressure. I doubt any proper system would fluctuate that much and it would most likley never be used, but a simple blown pump fuse could happen and this would save the motor.

At least him, or anyone reading this is getting 2 really good points of view. Sounds like he found a guy local to him to do the plumbing, I'm sure he'll advise on which way he thinks is best.

you going to PGD's next year ?

I think part of this is a lot of people put the hobbs on the solenoid side of the regulator. If used on the pump side of the regulator it would do a lot more good there without as much worry about switching on and off.

even with my cheap lil fuel pump thats in mosts opinion underfueling my motor i run it at nine pounds on a hard launch it drops to 7 and proceeds to climb back to the 8 1/4 mark or so and stay there until i lift at wich point it spikes back to a steady 9 psi at the gauge.. and i know my marshal fuel gauge is good i psi check it often..

Originally posted by motown/malibu:
even with my cheap lil fuel pump thats in mosts opinion underfueling my motor i run it at nine pounds on a hard launch it drops to 7 and proceeds to climb back to the 8 1/4 mark or so and stay there until i lift at wich point it spikes back to a steady 9 psi at the gauge.. and i know my marshal fuel gauge is good i psi check it often.. If you set it at 9, it drops to 7 climbs to only 8.25 then back to 9 when you are done, you have answered your question - your pump is NOT ADEQUATE. 1/2 psi can make a big difference in your fuel curve.

If you set it at 8 psi for example with an adequate pump and reg - it would stay very close - ALWAYS.

Your pump should be capable of providing the necessary volume at 2 to 3 times the pressure you need at the carb or nitrous system. carb at 7 - pump at 21. etc

Mike - using your logic I assume you are running a hobbs on the carb side to the ignition too if you run a separate pump? And an oil pressure shut off also?

I'm with you on that one, his pump isn't adequate.

No I don't have an hobbs switch on the carb side or one on the oil pressure side for 2 reasons.
1- my engine is a 9.8-1 very mild street engine. If the pump quits it'll run out of gas before it hurts it'sself. I did see a blower car torch the head gasket this summer because the guy forgot to fill the cell before the run. BUT it's a power adder car, yours might burn up with 15-1 comp, but how many passenger cars burn pistons when they run out of gas ? none.

2- the oil pump is mechanical. I'm looking into switching my motor over to a mechanical pump.

What I'm saying is - you can wrap yourself head to toe with 10 inches of bubble wrap - and still get killed crossing the road without COMMON SENSE.

The only difference is that more people stop to look because they have an uncontrollable urge to pop some of the bubbles.

I'm starting to think that common sense ain't that common.

There are some very good tips on Nitrous useage and bottle warming at 505Nova's website "Dragstuff.com" and "fastlanenitrous.com" Both of these sites have usefull N2O information that might save you some grief.

okay will check them out thanks..

Originally posted by 66 283:
What I'm saying is - you can wrap yourself head to toe with 10 inches of bubble wrap - and still get killed crossing the road without COMMON SENSE.

The only difference is that more people stop to look because they have an uncontrollable urge to pop some of the bubbles.

I'm starting to think that common sense ain't that common. :D :D Ryan that was the funniest thing i have heard in a while. Still got your old center section in my car. This year I'm going to see if I can break it. smile.gif

Motown, What pump were you running and what do you want for it. PM me! I have been looking at the Product Engineering stuff and just can't pop for it with all the other $$ upgrading my car right now. Its time to say good by to my mechanical Carter. I've got a mallory 110 to run on the juice side but I need something at a good price for the motor.

Gearheads78,

Good to know I don't sell junk! I keep the junk to run or myself and sell the good stuff.

I can't remember, was that a 3.70 center section 31 spline ford 9" with auburn pro? That must have been 3 or 4 years ago!

Originally posted by 66 283:
Gearheads78,

Good to know I don't sell junk! I keep the junk to run or myself and sell the good stuff.

I can't remember, was that a 3.70 center section 31 spline ford 9" with auburn pro? That must have been 3 or 4 years ago! Its a 4.10 gear. Yea its been a while the car stays on the back burner a lot. This year is going to be different. I am selling my mild mid 7 sec 383 street motor and building a 406 that is not so mild. Gunning for low low 6's this year. graemlins/thumbsup.gif