The V8 Owners Forum - Forum Index The V8 Owners Forum -
Welcome to the well-known V8 Owners Forum, no matter what you drive if its V8 Powered you'll be made very welcome.
 
 GarageGarage   1/4 Mile Table1/4 Mile Table 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Jet size
Goto page 1, 2, 3  Next
 
Post new topic   Reply to topic    The V8 Owners Forum - Forum Index -> Nitrous Oxide Area
View previous topic :: View next topic  
Author Message
JSF55
Gold Member
Gold Member


Joined: 04 Dec 2006
Posts: 970
Location: Swansea

1955 Ford Popular 103e

PostPosted: Sun Aug 22, 2010 12:13 pm    Post subject: Jet size Reply with quote

Oh well, bit the bullet and bought a second hand nitrous kit ! it's a sniper kit, cheap enough at the time and some gas in the bottle Very Happy
the jets are marked
Nitrous/Fuel Jetting Approximate
Power Gain
Approximate N20
Consumption Rate
47 / 53 100 HP 1.00 lbs. / 10 sec.
55 / 61 125 HP 1.25 lbs. / 10 sec.
63 / 71 150 HP 1.50 lbs. / 10 sec.
Now the motor in the car is using a bit of oil Wink so i don't want to kill it yet, any advice on a smaller jet size to run say 50 hp more and wil it suffice to tap into the origianl fuel line, it is 10mm bore so a short burst shouldn't be a problem ? john
_________________
So thats where it went !
Back to top
View user's profile Send private message Visit poster's website
JSF55
Gold Member
Gold Member


Joined: 04 Dec 2006
Posts: 970
Location: Swansea

1955 Ford Popular 103e

PostPosted: Tue Aug 24, 2010 9:33 am    Post subject: Reply with quote

No one got a guess ?
_________________
So thats where it went !
Back to top
View user's profile Send private message Visit poster's website
dbv8
Knows His Stuff
Knows His Stuff


Joined: 21 Jul 2008
Posts: 477
Location: Barrow-in-Furness

1998 TVR Chimaera

PostPosted: Tue Aug 24, 2010 4:24 pm    Post subject: Reply with quote

I know a little about nitrous but ony the wizards stuff sorry.
Try giving Real Steel or any NOS distributor a ring.
_________________
10.612 @ 129.77
176.5 standing mile.
Back to top
View user's profile Send private message
mgbv8
Gold Member
Gold Member


Joined: 18 Nov 2006
Posts: 5326


1975 MG MGB GT V8

PostPosted: Tue Aug 24, 2010 10:21 pm    Post subject: Reply with quote

Jet sizes that I have from my old NOS system are


36 nos 42 fuel = 50hp
42 nos 47 fuel = 75hp
47 nos 53 fuel = 100hp
55 nos 61 fuel = 125hp
63 nos 71 fuel = 135hp
73 nos 82 fuel = 150hp

This is where I gave up and went over to Wizards stuff...
_________________
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw

https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
Back to top
View user's profile Send private message Send e-mail
JSF55
Gold Member
Gold Member


Joined: 04 Dec 2006
Posts: 970
Location: Swansea

1955 Ford Popular 103e

PostPosted: Tue Aug 24, 2010 10:23 pm    Post subject: Reply with quote

Cheers Perry, i just might give that a try, john
_________________
So thats where it went !
Back to top
View user's profile Send private message Visit poster's website
ian.stewart
Moderator
Moderator


Joined: 18 Nov 2006
Posts: 2419
Location: Far Far south, any further south and my feet are wet


PostPosted: Tue Aug 24, 2010 10:47 pm    Post subject: Reply with quote

dbv8 wrote:
I know a little about nitrous but ony the wizards stuff sorry.
Try giving Real Steel or any NOS distributor a ring.


Real Steel have stopped selling any nitrous kit,
I used the Holley/NOS website help line
_________________
THE SMOKING GNU
12.604 with an old boiler of a RV8 and no gas
WHY are there so many IANS on this site???????
Back to top
View user's profile Send private message
mgbv8
Gold Member
Gold Member


Joined: 18 Nov 2006
Posts: 5326


1975 MG MGB GT V8

PostPosted: Wed Aug 25, 2010 8:32 pm    Post subject: Reply with quote

As Ian says!
Real Steel are now just selling off old stock.

Just make sure that you can deliver 5-6 psi steadily to the carb and nitrous system when spraying at full power.
And make sure your bottle pressure is at least 800 psi when you use it. Otherwise it will feel lame, run rich and waste gas.

Perry
_________________
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw

https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
Back to top
View user's profile Send private message Send e-mail
dbv8
Knows His Stuff
Knows His Stuff


Joined: 21 Jul 2008
Posts: 477
Location: Barrow-in-Furness

1998 TVR Chimaera

PostPosted: Thu Aug 26, 2010 8:03 am    Post subject: Reply with quote

A bottle heater with a pressure switch is the best set up to keep the pressure up and consistant.

You can set the switch to turn the heater off at say 950 psi.
Make sure you either do a static test or check the plugs at this level as you may need to richen the fuel.
More likely the fuel ratio will still be fine but your hit from the gas will double! Twisted Evil
_________________
10.612 @ 129.77
176.5 standing mile.
Back to top
View user's profile Send private message
JSF55
Gold Member
Gold Member


Joined: 04 Dec 2006
Posts: 970
Location: Swansea

1955 Ford Popular 103e

PostPosted: Thu Aug 26, 2010 6:19 pm    Post subject: Reply with quote

It doesn't seem to be as easy or cheap as i first thought Sad i'll have to see how i get on with selling some other bits first !
_________________
So thats where it went !
Back to top
View user's profile Send private message Visit poster's website
mgbv8
Gold Member
Gold Member


Joined: 18 Nov 2006
Posts: 5326


1975 MG MGB GT V8

PostPosted: Fri Aug 27, 2010 1:13 pm    Post subject: Reply with quote

Put up a picture of the kit !!
Then we can see what else you might need. There are shortcuts to getting bottle pressure up just before a race Wink
_________________
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw

https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
Back to top
View user's profile Send private message Send e-mail
JSF55
Gold Member
Gold Member


Joined: 04 Dec 2006
Posts: 970
Location: Swansea

1955 Ford Popular 103e

PostPosted: Fri Aug 27, 2010 7:01 pm    Post subject: Reply with quote

Will take some pics tomorrow Smile
_________________
So thats where it went !
Back to top
View user's profile Send private message Visit poster's website
JSF55
Gold Member
Gold Member


Joined: 04 Dec 2006
Posts: 970
Location: Swansea

1955 Ford Popular 103e

PostPosted: Sat Aug 28, 2010 9:55 am    Post subject: Couple of pics Reply with quote



It's a sniper kit ?
_________________
So thats where it went !
Back to top
View user's profile Send private message Visit poster's website
mgbv8
Gold Member
Gold Member


Joined: 18 Nov 2006
Posts: 5326


1975 MG MGB GT V8

PostPosted: Sat Aug 28, 2010 8:04 pm    Post subject: Reply with quote

That brings back memories. My first kit was a sniper.
You have all you need to get started. I would invest in a wizards fuel pressure switch at least. This will save you a lot of potential headaches.
The 14 foot braided line may well be far too long. Best bet would be to route it the shortest way possible to the n2 solenoid and then cut it to length and fit a nother -4 end. You can get eh -4 connectors from Pirtek or wizards and many other places. So as long as your bottle has enough pressure you can get going.
_________________
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw

https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
Back to top
View user's profile Send private message Send e-mail
JSF55
Gold Member
Gold Member


Joined: 04 Dec 2006
Posts: 970
Location: Swansea

1955 Ford Popular 103e

PostPosted: Sun Aug 29, 2010 5:24 am    Post subject: Reply with quote

I can easily get the hose done, truck fitters boy works for pirtek, any pointers on the fuel pump side?I've read some here, but it seems to be overly complicated
http://www.centuryperformance.com/fuelish-tendencies-understanding-fuel-pressure-and-volume-spg-140.html
_________________
So thats where it went !
Back to top
View user's profile Send private message Visit poster's website
sidecar
Top Dog
Top Dog


Joined: 04 Feb 2007
Posts: 2299



PostPosted: Sun Aug 29, 2010 8:31 am    Post subject: Reply with quote

JSF55 wrote:
Any pointers on the fuel pump side?



I'm in the same boat as you as I'm about to fit a PowerShot system to my Cob replica. I was also wondering what to do about the fuel pump. I tested my pump for litres flowed per minute, my pump pushes out 1.9 litres which is good enough to make 400 BHP.

BHP= (CC of fuel per minute) / 4.7

I've also monitored the fuel pressure at WOT and peak revs, it was around 6-7 psi (From memory).

My lump makes 285 BHP so in theory there is enough 'spare fuel' available for a 75 BHP NOS kit.

Having said all that I chickened out of using the pump, I then decided that a second small Facet cube pump would be good, the pump would be activated as soon as the NOS system was armed, it would be running before the NOS actually fired. The problem with this is setting up another fuel line etc.

I then decided to just change the pump that I have now as this would be easier. I'm going to fit a Carter 72 g/h jobbie, the lower pressure one so as as not to flood the Eddy carb. I feel that this is better because if I run a second fuel line it could remain 'air-locked' until the fuel solenoid opened. (Some sort of small bleed into the other fuel line might get round this).

When I checked out what pump I have now I was surprised to find out that Facet only rate it for 150 BHP engines, they must build in a huge safety margin into their figures!

Other things that I'm doing are fitting a low fuel pressure NOS system cut off switch and an RPM window switch. (I think the the pressure switch may not be needed with the new fuel pump but I've already order it)

Hope that helps!


EDIT...Just read the article that you posted a link up to, it's very interesting and it does show that my simple calculation may not be good enough! The weird thing is that I did measure the fuel pressure at WOT and peak revs (not an easy thing to do!) and the pressure did not drop 1 psi compared to the pressure at tickover. By the way I don't run any form of regulator, just a low pressure pump connected straight to the carb.

Why is nothing simple? Confused

Pete


Last edited by sidecar on Sun Aug 29, 2010 1:43 pm; edited 1 time in total
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    The V8 Owners Forum - Forum Index -> Nitrous Oxide Area All times are GMT
Goto page 1, 2, 3  Next
Page 1 of 3

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
Make payments with PayPal - it's fast, free and secure!


Copyright www.v8forum.co.uk 2006. All Rights Reserved,
Forum Disclaimer: Any posts in the V8 Forum are posted by individuals acting in their own right and do not necessarily reflect the views of the owner, administrators or moderators.