creechboy12

have a 99 lq4 iron head installed a wet kit on it and i just wanna make sure im not running it to lean and was wondering what other folks were running for jetting size...

currently running
60psi fuel pressure with a .042 fuel jet
900-950 bottle pressure with a .061 nitrous jet


truck hits pretty hard and runs good just worried about being lean.... having a hard time reading the plugs.

Doug G

The Fuel jet size should be 0.031"

A Nitrous jet size of .061" should produce:
168.04 HP with 1 port(s)

Actual HP to the wheels: 142.83 HP

This is only for a base/starter tune-up. ONLY way to know 100% is to read your plugs.

creechboy12

tried posting the plugs but nothing.....

i strated with those jet sizes and it woke it up but didnt feel like a "170HP" hit would so thats why i worried about being to lean.

Im gonne retry the pics of the plugs so you can see.

Thanks for the reply!

creechboy12

creechboy12

ok so!

First plug tr6 ngk plug .032 fuel jet .061 nitrous

Second plug switch to br7ef (two steps colder) plugs same jets.

Third plug same br7ef plugs again but .042 fuel jet and same .061 nitrous jet.

on the third pass (last plug reading) truck hit great and seemed to pull a bit harder might be my mind playing games but i think it was better.

Doug G

Do NOT use projected tip plug and nitrous

And when looking at the color....you're looking at the base of the porcelain.

Like here....

creechboy12

Awesome thanks for the info! Ill make a pass tomorrow with new plugs and see if we cant come to a conclusion on this!

Thanks again!

NitrousExpress

iTrader: (4)

Also on the plug reading after the pull/pass you need to immediately kill the vehicle and coast to a stop.


-Chris

creechboy12

Thats what im doing i have some free time tomorrow so ill try it out again with new plugs and see what happens.

What are people running for timing ?

NitrousExpress

iTrader: (4)

The general rule for pulling timing is 2* retard per 50hp.

-Chris

RENE'S RAGE

iTrader: (96)

Can you drive your car to the staging lanes or do you need to pull it, to get a good plug reading?

creechboy12

Yepp we have a serious issue...

I stalled new plugs same br7ef with the same jets (.042 fuel & .061 nitrous)

Pulled on street sprayed it coasted to a stop pulled plug this is what i got. Definitely not good....

NitrousExpress

iTrader: (4)

That is lean!! You need to add some fuel to it. Also it's a little hard to gauge where the timing mark is...


-Chris

creechboy12

Yeah were checking solenoids now hopefully we find a problem. Fuel pressure isnt changing but maybe 5 psi so were thinking a bad solenoid.... Ill have more pics up later if we can find a solenoid or another problem.

creechboy12

So we found the solenoid was weak we installed a fuel pressure gauge between the fuel rail and solenoid it got 52-60 psi.... Installed the fuel gauge after the solenoid only getting 10 psi from solenoid to fogger BOOM! So we installed new jets as if we were running 10 psi and for 150 shot which the jets were something like .061 nos ad. .051 fuel. The next hit was a huge difference you could just hear it screaming! And also got some tan on the plugs!!! So going to get new solenoids today and re run everything back to the way i haf it.


What kind of shot can a NOS fogger handle ?!?

NitrousExpress

iTrader: (4)

A weak noid will definitely cause some problems in more way than one. I'm glad you were able to find the issue and are getting is resolved.

Depending on the option for the fogger you should be able to spray anywhere from 400-500hp easily.

-Chris

creechboy12

Sweet! Thanks for the reply! I got picked up new cheater solenoid so im gonna go threw the process of checking pressures again the make apass then report back
Thanks again!

creechboy12

I know pictures are awesome and help other people solve there issues!
Heres how i did it. I took my purge adapter (silver adapter in pic) hooked it up BEFORE AND AFTER solenoid to get a proper fuel reading for each side. Installed my fuel pressure gauge to that adapter log and watched each side of the solenoid for pressure. BOOM she worked great gets 54psi on fuel delivery side of the solenoid and 46psi on the out side. Just knowing the differce on each side will help with proper jetting.

Ill be making a test pass in a bit and post pics of plugs with the new solenoid.

ATwelveSec02Z28

iTrader: (17)

This is the importance of having your system flowed, and maintained. Weak magnets, dimpled plungers etc can cause severe issues