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Discussion Starter · #1 ·
This is a Street Car that I take to the Drags 1-2 times a Year.

This is My Setup

2003 Nissan 350Z VQ35DE Motor, 3.5 L, All Alum, V6, Dual OH Cams, Stock Block

Vortech SC-Trim Supercharger with 15 Lbs of Boost, Headers, no cats, exhaust, 600cc injectors, ect......

Using the Innovate LM-1 and AUX Box for AFR's, Boost, RPM, ect.

Split Second FTC1 PiggyBack ECU for Fuel and Timing Control.

I'm in the process of Tuning, started out very fat just for a base. 10.1 to 10.5 in boost.

Leaned it up a bit to 11.3's in low boost, 10.8's in high boost made 476whp/389wtq. Pulled very well.

Leaned it up more to 11.5's in low boost, 11.1's in high boost made 491whp/404wtq pulled very well, almost to redline. Stronger

Leaned it up more to 11.9's in low boost, 11.6's in high boost made 363whp/382wtq. Power fell way off, and fell off a bunch after peak power.

So, is this tell me or you, my motor like low 11's in boost?

Also, why would the power drop 25whp with this little change?

Ya, I know read the Plugs..... Hard to do, I'm not at the Drag Strip.

Thanks,

TimRod
 

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What does the timing curve look like and is there a knock sensor on this car that could be pulling timing ? It may just be that your combo likes that A/F ratio . There were no signs of detonation when you were making these pulls ? What type of ignition are you running ? What type of plug gap are you running? Is the car intercooled and what kind of IATs are you seeing at 15lbs of boost ? I am guessing you are running the car on 93 octane ?
 

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Discussion Starter · #5 ·
What does the timing curve look like and is there a knock sensor on this car that could be pulling timing ? It may just be that your combo likes that A/F ratio . There were no signs of detonation when you were making these pulls ? What type of ignition are you running ? What type of plug gap are you running? Is the car intercooled and what kind of IATs are you seeing at 15lbs of boost ? I am guessing you are running the car on 93 octane ?
Typo in pull No3 (463)

Factory knock sensor

93 octane

Timing 15/16* max tq @5800, 19* max hp @ 6400 -7100

4 x 12 x 24 core a/a intercooler

I need to log IAT's
 

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Discussion Starter · #6 ·
Factory Ignition

Ngk Iridium Plug, I was running .034", I put in a new set for this tune and left them at .44" to see if I'd get any blow out, no signs of blow out.
 

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Do you have the capability to datalog the ignition and if you do was there any timing being pulled during the pull by the knock sensor ? .044 seems like alot of gap especially for a factory ignition.
 

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I'll assume that your combo works much the same as a boosted V-8... First thing I'd do is get rid of the Iridium plugs. I've heard that the tiny electrode gets really hot , and can cause detonation in a boosted combo.
 

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Discussion Starter · #10 ·
Do you have the capability to datalog the ignition and if you do was there any timing being pulled during the pull by the knock sensor ? .044 seems like alot of gap especially for a factory ignition.
No......
 

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Well I guess there are a few things that you can try if you plan on putting the car back on the chassis dyno . You can try running a higher octane fuel and see if detonation was the cause of the fall off in power . I would also do as mentioned above and get rid of the plugs you have and try a NGK V Power non resistor plug in a colder heat range than what you are running , maybe two heat ranges . I would close the gap up to .030 as the spark does not have to bridge such a large gap and will be less likely to be blown out . If you can figure a way to monitor your IATs I would see how high they are . Especially on a chassis dyno the IATs are probably high unless you cooled it down before your pull as once A/A intercoolers heat soak it is as if you are running non intercooled . Even with a fan blowing on it usually that is not sufficient . Without being able to datalog what your ignition is doing you really are guessing wether your knock sensor is pulling timing or not . The higher octane fuel should suppress detonation and you should be able to see if you car likes a leaner A/F ratio or if you lost power with the leaner A/F ratio because of detonation . All said your combo just may need the fatter A/F ratio but the above is how I would go about it finding out .
 

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Discussion Starter · #12 ·
Well I guess there are a few things that you can try if you plan on putting the car back on the chassis dyno . You can try running a higher octane fuel and see if detonation was the cause of the fall off in power . I would also do as mentioned above and get rid of the plugs you have and try a NGK V Power non resistor plug in a colder heat range than what you are running , maybe two heat ranges . I would close the gap up to .030 as the spark does not have to bridge such a large gap and will be less likely to be blown out . If you can figure a way to monitor your IATs I would see how high they are . Especially on a chassis dyno the IATs are probably high unless you cooled it down before your pull as once A/A intercoolers heat soak it is as if you are running non intercooled . Even with a fan blowing on it usually that is not sufficient . Without being able to datalog what your ignition is doing you really are guessing wether your knock sensor is pulling timing or not . The higher octane fuel should suppress detonation and you should be able to see if you car likes a leaner A/F ratio or if you lost power with the leaner A/F ratio because of detonation . All said your combo just may need the fatter A/F ratio but the above is how I would go about it finding out .
I will go with an NGK copper plug and gap it to .030"
Like I said, the NGK Iridiums were gaped to .032" prier to this tuning, now are at .044".
and do a test with some race gas.
Thanks so much,

TimRod
 

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Discussion Starter · #15 ·
My fuel system was maxed out. To small of Main Fuel Line. Installed Complete new System with -10 Feed and -8 return and larger fuel pump.....
Final Results

513whp/408wtq 93 octane Street tune

540whp/436wtq 105 Race Tune :D
 

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Discussion Starter · #17 ·
Best to date....MARCH 29,2012


R/T----- .068
60'----- 1.704
1/8----- 7.533
MPH----- 96.65
1/4----- 11.647
MPH----- 120.48
 

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if the engine isn't happy, stop and make it happy, do not force your opinion onto the engine, the engine is trying to tell you what makes it happy, DON'T ignore it
 
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