dyno results?

[sli240sx]

whats up everyone, just dyno my car and didn't get what i expected. I have a full built motor with CP pistons 8.5 to 1, BC rods, HKS 264 step 2 cams, Greddy intake manifold, Ferrea oversized valves and springs and retainers, Tomei ex manifold, Greddy elbow, EX engineering down pipe, HKS High power, and a GT2871R .64 ar. I was expecting at least 350whp but I only was able to reach 318whp. I have a Power FC controlling the fuel with 740cc injectors. The power also starts dying at around 6400 rpm which suck. The tuner said it might be the sparks are too cold or the cam timing is off. I was wondering if I could be due to the VTC system that is still connected. Also my hydrolic lifters are also making some loud valve chatter. Would that cause a power loss? If someone could chime in that would be great.

[sli240sx]

oh I forgot to mention that I was running 19.5 psi reaching it at 4000 rpm.

[kingtal0n]

Did you have the motor built by mesa balancing

I have noted with BC springs/retainers/camshafts the valvetrain is very noisy even at idle especially if the head and block was decked.

as to your power, power follows airflow, and complete combustion.You should start with the simple and work backwards:

boost leakrestrictions (air filter, inlet pipe, outlet pipe, throttle body)crappy intercooler (check inlet temps)timing (actual)too rich (wideband actual)

those are pretty easy to check and can influence power +/- 50-80 HP worththe cams should be straight up from BC I hope you dont have adj cam gears

from there, you need to see how much fuel its actually using compared to the power its making. the PFC will say Inj duty cycle, if your anywhere near 80-90% then something is wrong, with 300HP a set of 550s would be around 80% at stock pressure, so you should be more like 50-60% Duty cycle. If this is the case, then the computer KNOWS how much power the engine is making, which means thats exactly what its doing: the problem lies with airflow, not fueling or timing related.

On the other hand, I have seen instances where the engine is injesting 400HP worth of airflow, but the spark is weak and power extraction in the combustion chamber is poor. The best way to check for this situation is a set of iridium spark plugs and an EGT gauge. If the 400HP worth of fuel is going in, and the 400HP worth of air is going in, and only 70% of it is being burnt, you will see 2 things: #1 Air fuel will look correct#2 EGT will rise as torque peaks and begins to fall and combustion gets worse.

the iridium plugs will temporarily remedy the situation and power production will rise dramatically and EGT will drop and air fuel will get richer. At that point, if you pull the fuel out of it and re-correct your new air/fuel, power production should be where it should be.

although, its probably just a boost leak

[sli240sx]

Hey bro thanks for the info!

My motor head and block was decked, I don't know if built by mesa balancing. My head was given a valve angle job i dont know if thats what you mean by mesa balancing?

For boost leak I don't think I have one the only leak I have is coming of the elbow of the turbo but I don't think that would make me loose that much power. I still have to fix that problem. That five bolt patter sucks! I can't even get a wrench down there.

As far as restrictions I just bought a greddy intake filter. I have a larger throttle body 70mm so i'm good there. inlet size is a litter smaller that 70mm and the outlet is about 2.5 I think.

For checking the temp on the inlet how would I do that? I don't think the PFC check the temp on that.

Timing: It sould be the stock timing I don't have adj cam gears. But I am going to change the lifters to solid one. I hope that would help with the power and timing. Maybe the valves are not opening and closing in time? Have you ever heard of BLE solid lifters? They look very good but I don't know the quailty of the piece and they are fully adjustable.

Too rich: Well when I floor It my AEM reads around 11.5 mixture.

I also checked the Duty cycle and its running around 50% or so which is good.

I also bought some new plugs. At the dyno I had brand new NGK iridium plugs. I had NGK iridium 8's gapped at .030 so now i have the same just 7's and the same gap. The car at least starts better now. should I be at a smaller gap than that or is .030 good?

I'm going to see how it feels after I change the lifters. Maybe thats the problem. It is making a lot of valve nose under there. I hope those lifters improve something. I don't need to change the cams again do I? I already have some agressive cams. Will see, if anyone else has ideas let me I would appreciate it.

[0range_Kouki24O]

Did you have the motor built by mesa balancing

I have noted with BC springs/retainers/camshafts the valvetrain is very noisy even at idle especially if the head and block was decked.

as to your power, power follows airflow, and complete combustion.You should start with the simple and work backwards:

boost leakrestrictions (air filter, inlet pipe, outlet pipe, throttle body)crappy intercooler (check inlet temps)timing (actual)too rich (wideband actual)

those are pretty easy to check and can influence power +/- 50-80 HP worththe cams should be straight up from BC I hope you dont have adj cam gears

from there, you need to see how much fuel its actually using compared to the power its making. the PFC will say Inj duty cycle, if your anywhere near 80-90% then something is wrong, with 300HP a set of 550s would be around 80% at stock pressure, so you should be more like 50-60% Duty cycle. If this is the case, then the computer KNOWS how much power the engine is making, which means thats exactly what its doing: the problem lies with airflow, not fueling or timing related.

On the other hand, I have seen instances where the engine is injesting 400HP worth of airflow, but the spark is weak and power extraction in the combustion chamber is poor. The best way to check for this situation is a set of iridium spark plugs and an EGT gauge. If the 400HP worth of fuel is going in, and the 400HP worth of air is going in, and only 70% of it is being burnt, you will see 2 things: #1 Air fuel will look correct#2 EGT will rise as torque peaks and begins to fall and combustion gets worse.

the iridium plugs will temporarily remedy the situation and power production will rise dramatically and EGT will drop and air fuel will get richer. At that point, if you pull the fuel out of it and re-correct your new air/fuel, power production should be where it should be.

although, its probably just a boost leak

[kingtal0n]

Hey bro thanks for the info!

My motor head and block was decked, I don't know if built by mesa balancing. My head was given a valve angle job i dont know if thats what you mean by mesa balancing?

For boost leak I don't think I have one the only leak I have is coming of the elbow of the turbo but I don't think that would make me loose that much power. I still have to fix that problem. That five bolt patter sucks! I can't even get a wrench down there.

As far as restrictions I just bought a greddy intake filter. I have a larger throttle body 70mm so i'm good there. inlet size is a litter smaller that 70mm and the outlet is about 2.5 I think.

For checking the temp on the inlet how would I do that? I don't think the PFC check the temp on that.

Timing: It sould be the stock timing I don't have adj cam gears. But I am going to change the lifters to solid one. I hope that would help with the power and timing. Maybe the valves are not opening and closing in time? Have you ever heard of BLE solid lifters? They look very good but I don't know the quailty of the piece and they are fully adjustable.

Too rich: Well when I floor It my AEM reads around 11.5 mixture.

I also checked the Duty cycle and its running around 50% or so which is good.

I also bought some new plugs. At the dyno I had brand new NGK iridium plugs. I had NGK iridium 8's gapped at .030 so now i have the same just 7's and the same gap. The car at least starts better now. should I be at a smaller gap than that or is .030 good?

I'm going to see how it feels after I change the lifters. Maybe thats the problem. It is making a lot of valve nose under there. I hope those lifters improve something. I don't need to change the cams again do I? I already have some agressive cams. Will see, if anyone else has ideas let me I would appreciate it.

I dont recommend changing the lifters to solid with your setup.There is no reason to, you will take a perfectly good daily driver setup and make it a possible headache for nothing. not to mention those cams are not designed to be used with solids, doesnt mean it wont work, just means you wont take advantage of the solid lifters becauseA: the valve opening/closing ramps are smooth and subtle for hydraulics B: solids allow you RPM without FLOAT. Right now you run out of power before you float your valves, which means your hydraulics are doing the job just fine.

If the torque starts getting choppy at high RPM and fueling gets weird and torque seems to just plummit along with power it MIGHT be valve float.But this probably isnt the case.

the plugs are fine the gap ONLY needs to go smaller if it starts to breakup or miss/backfire due to insufficient spark energy.

11.5 is FINE for 93 octane, you should have about 9-12* of timing around peak torque maybe even less. You can make more power by leaning it out some 12:1 or even 12.5:1 but dont go very far off into the red (not much past 15PSI) that turbo runs out of breath with your mods and things start getting hot real quick.

and just because its a name brand filter doesnt mean its not a restriction.

if its a MAP power FC then there is an intake air temp sensor and it should be in your intake manifold. If its a MAF PFC then there wont be any sensor.

your inlet tube could be a restriction or even the turbo outlet. playing around with plumbing can give you some awsome changes in powerband.

[sli240sx]

I was checking my power FC and I do have the option to monitor the air inlet temp but It's not connected. I think I have to purchase the sensor and harness to make it work. I don't have the D-jetro.

Should I rest the timing on the car? I think I have the stock timing do you think I should advance it a little. Also would that be possible without the adjustible cam sprockets?

Ok so no solid lifters maybe I need some new hydraulics lifters then cause that noise is pretty bad. I thought hyd lifters are suppose to be quiet.