Nitrous help
Thread Starter
Burning Brakes
Joined: Oct 2005
Posts: 1,020
Likes: 18
From: Anderson SC
Nitrous help
I have a TNT kit jetted to a 150 shot. I have a completely stock engine. I've been told I can hit it with that shot from some people and told by others to upgrade the fuel pump first. Will the engine hold it or do I need to do the upgrade? Also, is the fuel pump all I will need to change to make the kit "safe"?
Le Mans Master
Joined: Aug 2001
Posts: 7,064
Likes: 18
From: Arizona
Originally Posted by 2kvert
I have a TNT kit jetted to a 150 shot. I have a completely stock engine. I've been told I can hit it with that shot from some people and told by others to upgrade the fuel pump first. Will the engine hold it or do I need to do the upgrade? Also, is the fuel pump all I will need to change to make the kit "safe"?
Pro
Joined: Nov 2002
Posts: 722
Likes: 0
From: ********************* Florida's Space Coast *********************
Originally Posted by 2kvert
I have a TNT kit jetted to a 150 shot. I have a completely stock engine. I've been told I can hit it with that shot from some people and told by others to upgrade the fuel pump first. Will the engine hold it or do I need to do the upgrade? Also, is the fuel pump all I will need to change to make the kit "safe"?
Also spraying that much on a stock tune with full timing "may" be playing with fire. I would get the car on a dyno before doing too much spraying.... Just to be safe. Fuel is probably not going to be an issue at 150.
Burning Brakes
Joined: Aug 2004
Posts: 849
Likes: 1
From: Dallas TX
i was planning on running a 150 shot as well. i tried it out on the dyno friday. on my graph i could see where the fp dropped deactivating the nitrous by the fpss causing a spike down in power until the pump caught up after the initial pressure drop. however, after the pump caught up again it pulled throughout the run which indicates the stock pump can support the shot. i think the problem is the fuel jet is so large on a 150 shot that the pump cannot keep up initially.
Drifting
Joined: Dec 2002
Posts: 1,472
Likes: 1
From: Reynoldsburg oh
Originally Posted by creighton
i was planning on running a 150 shot as well. i tried it out on the dyno friday. on my graph i could see where the fp dropped deactivating the nitrous by the fpss causing a spike down in power until the pump caught up after the initial pressure drop. however, after the pump caught up again it pulled throughout the run which indicates the stock pump can support the shot. i think the problem is the fuel jet is so large on a 150 shot that the pump cannot keep up initially.
This is why on alot of dyno graphs you will see that initial hit of the spray and the a/f will go lean for that split second when the nitrous comes on. It is the fuel soleniod cleaning the fuel rails out and sucking them dry for a sec until the pump catches back up. Its really not a big deal, alot of cars have them unless you have progressive controller to get rid of the initial 150hp hit.
Burning Brakes
Joined: Aug 2004
Posts: 849
Likes: 1
From: Dallas TX
you're right sprayedc5, i did see a lean spike when the nitrous hit. that's what lead me to the conclusion of the problem. i just didn't gain enough power on the 150 shot to justify it at this time. i picked up 110whp on a 100 shot. for some reason i didn't pick up 150 whp on a 150 shot though.
Collections Hold
Joined: May 2003
Posts: 3,520
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From: Tacoma WA
A conversion to regulator and return at the rails will cure the pressure drop at heavy demand. Also, KB bap can help this issue. The best way to get rid of the lean spike and low pressure issues.
Robert
Robert
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Drifting
Joined: Aug 2000
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From: Chapin SC
Cruise-In II Veteran
Cruise-In III Veteran
Brief lean spikes are typical and not caused by fuel pressure problems. I have wide band sensors on my system with data logging and I get a lean spike of about 16-17 to 1 for about 2/10 of a second with every nitrous activation. This is with a direct port fogger system that has an independent fuel tank and pump. The nitrous gas is under high pressure and gets to the cylinders faster than the fuel - that is what causes lean spikes. Lean spikes of very short duration will probably not hurt your motor.
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Joined: May 2003
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From: Tacoma WA
Originally Posted by JerryL
Brief lean spikes are typical and not caused by fuel pressure problems. I have wide band sensors on my system with data logging and I get a lean spike of about 16-17 to 1 for about 2/10 of a second with every nitrous activation. This is with a direct port fogger system that has an independent fuel tank and pump. The nitrous gas is under high pressure and gets to the cylinders faster than the fuel - that is what causes lean spikes. Lean spikes of very short duration will probably not hurt your motor.
Try lenghting your nitrous line, that'll help the little spike you have.
Robert
Last edited by Robert56@RNS; Apr 10, 2006 at 08:59 PM.