Jet size

JSF55 · Post by **JSF55** » Sun Aug 29, 2010 12:40 pm

Simple ! not cheap either

i think it's time versus getting it right in time for 1 event ??? hhhmmmm

thanks for the info pete, be nice to see some others installs? john

mgbv8 · Post by **mgbv8** » Sun Aug 29, 2010 5:07 pm

I have twin pumps. The one for the nitrous feeds 15psi via a 1/2" bore line to the engine bay. This connects to a twin outlet regulator that feeds both my fuel solenoids. This is a dead head setup at the moment. But I do know how to adjust it. This is less fiddly than feeding both systems from one pump.

sidecar · Post by **sidecar** » Sun Aug 29, 2010 6:07 pm

mgbv8 wrote:I have twin pumps. The one for the nitrous feeds 15psi via a 1/2" bore line to the engine bay. This connects to a twin outlet regulator that feeds both my fuel solenoids. This is a dead head setup at the moment. But I do know how to adjust it. This is less fiddly than feeding both systems from one pump.

Cheers for the info Perry.

I suspect that you setup is far more radical than the system that I'm going to fit

I'd appreiate you thoughts on the following setup bearing in mind that I'm only after 75 BHP for road use.

One Carter 72 GPH 8 PSI pump feeding a Holley bypass regulator set to 7 PSI with a return pipe to the tank (My carb is OK with 7 PSI at the moment).

The 7 PSI will feed the NOS system and the carb, I may or may not run a 7 PSI low pressure NOS cut off but I will run an RPM window switch.

I hope that I've not hijacked this thread.

mgbv8 · Post by **mgbv8** » Mon Aug 30, 2010 7:01 pm

sidecar wrote:
mgbv8 wrote:I have twin pumps. The one for the nitrous feeds 15psi via a 1/2" bore line to the engine bay. This connects to a twin outlet regulator that feeds both my fuel solenoids. This is a dead head setup at the moment. But I do know how to adjust it. This is less fiddly than feeding both systems from one pump.
Cheers for the info Perry.

I suspect that you setup is far more radical than the system that I'm going to fit

I'd appreiate you thoughts on the following setup bearing in mind that I'm only after 75 BHP for road use.

One Carter 72 GPH 8 PSI pump feeding a Holley bypass regulator set to 7 PSI with a return pipe to the tank (My carb is OK with 7 PSI at the moment).

The 7 PSI will feed the NOS system and the carb, I may or may not run a 7 PSI low pressure NOS cut off but I will run an RPM window switch.

I hope that I've not hijacked this thread.

No probs! All questions are good debate eh??
I used a Carter Marine pump to feed both my systems up to 100hp of gas. This was fine. But the Carter pump did wear out after 2 years. And no service kit available for mine??

To be honest, on low pressure systems you can feed the nitrous side with anything from 5-15 psi and just reduce the fuel jet accordingly based on performance and plug readings. Better to be rich than lean!!
My Sniper kit seemed to perform better at higher fuel pressure. I seemed to get more even fuel distribution. I guess thats down to the spray bar acting as a fuel log which filled up and gave even petrol across all the holes??

My first setup on the Sniper was with the original SU pump. This was great up to a 50 shot, just. But a pulsing pump was not the best idea really. I needed a rotary pump which delivered constantly.

You can fiddle with all sorts of setups. Bu the main thing to look out for is, can the pump deliver a constant flow at a constant pressure at full load?

If you are happy that the pump will feed the carb at full chat and still have enough left to feed the nitrous side then you will be ok.

My basic testing for this on any rig is to route my nitrous fuel line via whatever jets I'm using into a small plastic bottle which I strap in the engine bay or wherever is safe. I arm the nitous sytem (with the bottle turned off) and go and try some road runs. Hit the motorway and get to whatever rpm in 3rd gear then floor it for 10 seconds. This will feed the carb for the n/a run and should deliver X amount of petrol into the bottle. Measure what is in the bottle and if it ties up with at least what you need you know that the fuel system will deliver against the resistance of the carb and the nitrous fuel jets while you are running flat out. This may sound a bit Heath Robinson, but it works in the absence of specialised test equipment.

Perry

JSF55 · Post by **JSF55** » Mon Aug 30, 2010 7:19 pm

Mc gills on ebay just sent me a link to this, cheap ! but what do you reckon, better to go for something bigger ?
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... EL:GB:1123
oh i have cash in my paypal account !

sidecar · Post by **sidecar** » Tue Aug 31, 2010 5:01 am

JSF55 wrote:Mc gills on ebay just sent me a link to this, cheap ! but what do you reckon, better to go for something bigger ?
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... EL:GB:1123
oh i have cash in my paypal account !

That looks similar to the Facet 'Cube' pump. The PSI looks a bit low for the NOS system to me, I think that 7 PSI would be the minimum that you should go for. (But this is all new to me!).

32 GPH would be OK if you are using the pump for the NOS jets only.

Perry, cheers for the reply, your method of testing the low to the NOS fuel jets is a good one!

dbv8 · Post by **dbv8** » Tue Aug 31, 2010 8:23 am

A low pressure fuel supply is okk as long as its constant. You just need to establish the correct nitrous to fuel ratio you need for your set up.

I take my fuel from the injection supply which is regulated to 45psi.
Hence i run a ratio of about 2.5:1, ie a 250 nitrous jet and a 100 fuel gives me 125 bhp. The power is half the rating of the nitrous jet on a wizards of nos kit.

Perry, what ratio do you run with your lower pressure fuel supply?

JSF55 · Post by **JSF55** » Tue Aug 31, 2010 8:34 am

sidecar wrote:
JSF55 wrote:Mc gills on ebay just sent me a link to this, cheap ! but what do you reckon, better to go for something bigger ?
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... EL:GB:1123
oh i have cash in my paypal account !

That looks similar to the Facet 'Cube' pump. The PSI looks a bit low for the NOS system to me, I think that 7 PSI would be the minimum that you should go for. (But this is all new to me!).

32 GPH would be OK if you are using the pump for the NOS jets only.

Perry, cheers for the reply, your method of testing the low to the NOS fuel jets is a good one!

I looked at the other pumps they do, but noticed there all interupter type pumps, surely that would be worse?

mgbv8 · Post by **mgbv8** » Tue Aug 31, 2010 3:40 pm

dbv8 wrote:A low pressure fuel supply is okk as long as its constant. You just need to establish the correct nitrous to fuel ratio you need for your set up.

I take my fuel from the injection supply which is regulated to 45psi.
Hence i run a ratio of about 2.5:1, ie a 250 nitrous jet and a 100 fuel gives me 125 bhp. The power is half the rating of the nitrous jet on a wizards of nos kit.

Perry, what ratio do you run with your lower pressure fuel supply?

Hi big D

If I'm running 5-8 psi I do 1:1 ratio. But then I do experiment with up to 13psi flowing and adjust fuel jets depending on plug readings. its easy for me to do my flow tests because its a separate fuel pump. So i can just activate the pump and dump the fuel into a measuring jug. This allows me a bit of tuneability with the fuel side.

sidecar · Post by **sidecar** » Tue Aug 31, 2010 5:21 pm

Another update from me! (Not that I have a clue!)

I've just spoken to Earls who are the Bods that are supplying my NOS system. The bloke reckoned that a Holley 'blue' pump would work well for me along with the supplied regulator. It is a dead-head jobbie but he said that Holley supply them as a kit which implies that the pump is OK with this sort of regulator. The whole lot is about 130 quid which ain't too cheap!

http://www.earls.co.uk/earls/fuelsystem ... olley.html

I think that I will go for this setup and use the pump to supply the fuel at 7 PSI to my carb and the NOS system.

It better all be worth it!

mgbv8 · Post by **mgbv8** » Tue Aug 31, 2010 8:48 pm

The Blue pump will serve you well mate. Its what I use on the carb side. It used to be my nitrous pump until I fitted and Edelbrock pump on the gas side and retired my Carter pump a few months back

sidecar · Post by **sidecar** » Wed Sep 01, 2010 6:16 am

mgbv8 wrote:The Blue pump will serve you well mate. Its what I use on the carb side. It used to be my nitrous pump until I fitted and Edelbrock pump on the gas side and retired my Carter pump a few months back

Cheers Perry,

One more question! (That could be a bit of a lie!). A bloke on the Cobra Forum reckons that the Holley blue pump is mega noisy, how to you find it?

Cheers,

Pete

kiwicar · Post by **kiwicar** » Wed Sep 01, 2010 9:15 am

How would you tell on Perry's car??

Best regards
Mike

mgbv8 · Post by **mgbv8** » Wed Sep 01, 2010 12:52 pm

It does have an annoying drone Pete. But not as loud as the edelbrock pump... it is the most noisy pump I have owned

JSF55 · Post by **JSF55** » Thu Sep 09, 2010 7:49 pm

I've managed to get the plate under the carb, i then realised the coil packs were in the way

so lifted them and moved them back a bit, the way i had set up the fuel side men't the filter hit the breather filter

so i removerd it all and turned it through 180o so the fuel is at the rear and the nitrous line at the front, anyone see any other problems

crappy camera phone shot !