Hey guys,
So I have had my G35 about 2 years now and I finally got it tuned after slowing modding it.

My current list of mods:

Blox 5/8 Thermal Spacer
Kinetix High-Flow Cats
Strup Ceramic Headers
Stillin Z-Tube
Stillin PopCharger
E3 Spark Plugs

Mods Not installed yet:
Custom upper plenum
75mm "MaxBore" TB
TB Coolant Bypass
Ported Lower Plenum
Ported Intake manifold
Phenolic Gaskets

The car was tuned by EFI Logic @ Pompano Motorsports




Car wouldn't make over 250, despite hitting 250 around 5400rpm it stays at 250 until basically redline...
Thinking I might need a True-Dual exhaust for the car now.

 

Why would you tune it before you had all your breathers on? Also, what is you ultimate goal? There is a such thing as too much airflow on the exhaust side. If you've got headers and HFCs you're probably losing power from lack of back pressure. Opening up the exhaust even more is counterproductive unless your ultimate goal is to go FI. You can't necessarily just bolt on everything that promises HP and expect to gain everything the marketing campaign says. You need to have a goal in mind and build your car accordingly.

 

So you are saying that the Stock exhaust is capable of flowing more than this? Because its hitting a power wall at 250WHP.
As you see in the graph it basically hits 250WHP and stays there for ~1100RPM.
This doesn't speak of a car with too little back pressure, it speaks of a car with too much.
Usually if you cannot make power up top its due to too much back pressure.

I have to order a new gasket for the throttle body because it was lost.
The other manifold parts (other than the custom top plenum) are not finished yet (i haven't had time) and the reality is that I don't know how well the car would run with all this custom stuff without any sort of tune.

My goal is around 280WHP. I've seen it done, I want to do it.
Infact someone on here has 300WHP without cams on a DE.

 

I'm saying that for your build, a less extreme exhaust system would most likely yield better results. I didn't say the OEM exhaust flows better, but there is definitely a such thing as too much flow. I've seen the 300hp builds and they are definitely not focusing strictly on exhaust flow. In fact this motor is pretty tapped out from the factory save for around 40hp with bolt ons and tune. Those builds probably revolve around rotating mass weight relief. Light weight wheels, drive shaft, brake rotors, flywheel, AC delete, etc. Are all gonna translate into WHP.

 

You cannot be serious....
I build race cars lol.
Flywheel's don't add horse power.
Brake Rotors, wheels, AC Delete, none of them ever add horse power.
Turning off your AC and removing your AC... the difference in WHP is less than 1 in most places.

In the case of this car, the exhaust is holding it back.
if you reach peak power at a lower RPM than you should and it doesn't go up from there, this is a classic case of too much back pressure.
As someone who builds turbo cars, I've seen this happen so many times.

I'm just not sure the max flow of the stock exhaust if I change the y-pipe/midpipe.

 

Remind me not to drive any of the race cars you "build", lol.

As a former TTZ32 owner, the rule on most FI applications is less back pressure = better. THIS IS NOT FI - IT'S NATURALLY ASPIRATED!

Read Scraggle's post again - on NA applications, too little back pressure can hamper power output.

Also, note that Scraggle didn't state that any of those mods "make/add" power - rather they free up RWHP. Your crank HP will be the same, but the less work that that power has to due by moving heavier parts, etc. means more of that power is available hit your wheels.

In other words, when your fat girlfriend is in my car, it's slower because energy from the combustion in the motor that could have been used to propel the car forward now has to be used to haul a heftier load.

 

Another guy who knows nothing at all.
Reducing the cars weight never increases WHP.
Reducing rotating mass doesn't increase WHP.
Changing your breaks does not increase WHP.
Having less people in your car does not increase WHP.

If you lighten the car it will get faster yes, but the difference is so small that basically the only time it would make a difference is if you went from the stock wheels to like TE-37's that are 6lb.
But even then, it would then reduce your highway mileage as you would have less momentum and you would be under higher load.
So you would have slightly increased acceleration at the cost of higher load and less launching power.
The general rule of thumb is that every 50lb is 0.1sec 1/4 faster. By your guys logic, I should never fill my tank because the car will have more WHP on an empty tank.
Weight isn't my issue and the car doesn't "feel slower" when my skinny Asian wife is in my car either :P

Too little back pressure causes a reduce in TORQUE which as such hurts your low end power. Unless you have EXCESSIVELY high flow vs production.. you will not see any real loss in peak power. And even then it will be a small loss.
Considering that the car is making PEAK power at 1100-1200RPMs below redline when it has more mods installed which allow it to have a smoother powerband... well this screams too much back pressure.

 

Then why am I making 270 while you're at 250?

You're thinking of crank hp that is not impacted - whp is most certainly impacted by weight reduction.

 

Because you have a 2006 6MT which is a revup and makes about 20-30HP more from the factory vs mine.
It also comes with a much more free flowing exhaust in those years.

WHP is not impacted.
Please go make a dyno with 2 sets of Rims to show off this WHP gain of lighter rims.
I'd really love to see it.
There are so many factors that technically changing your tire compound could increase WHP as its measured to 3000lb rollers and there could be more/less friction.
This is also why automatic cars tend to lose more power to the wheels vs manual's.
Because the Torque convertor and auto tranny clutches are much heavier vs manual's.

But even if you reduced the wheel weight by 10lb per wheel... it wouldn't increase the WHP that much.

http://www.audizine.com/forum/showth...eel-horsepower

Check here, you can see the "gains" come more from a wider tire thus being able to easier spin the rollers as the 3lb gain only caused a loss of 1 WHP.
So tbh it all depends on the setup.
But when it comes to things like brake rotors... it won't make that much of a difference unless they make some super lightweight ones that also don't shatter.

 

Good luck, man. Haha you will not be getting to the 300whp mark.

Is this your racecar build?

 

Yes for sure, because now I proved that you know nothing you are going to talk crap?
Pretty sad how things are around here.

 

Bro, are you retarded? First of all, let me correct a few things for you:

The 06 had 15 more HP as a revup but 10ft-lbs less TQ.

Every 100lbs (not 50) of weight relief is the general rule for .1 second shaved off the 1/4mi.

We are not talking about just weight relief, we are talking about parasitic drive line loss. The general rule with a stock car is that you lose ~20% of your crank HP by the time the power get to the street.

Let's keep this simple for understandings sake, but if you have a motor with 100hp and then you attach it to a transmission, then a driveshaft, then a differential, then axles, then wheels, a whp dyno will read about 80hp..k? Still following.

Ok, so if you took off rotational mass in the drive line it would take less power to push those parts, resulting in less parasitic power loss. So, say you could drop your drive line loss from 20% to maayyybe ~12%; you would pick up 8% more HP to the wheels, so your whp dyno would then read 88hp instead of 80. Now go apply this to your racecar builds.

 

Hahaha..yeah, man..I'm the one who know nothing..keep going on your race car bro. I mean just put 6" pipes all the way back and you'll suddenly be putting down 600hp cuz of all that fllooowwww.

 

how dense are you? it won't add horsepower. but it uses less when you have less rotating mass. energy that your engine cam put to better use instead of the extra effort it would take to move with 30 lb wheels compared to 18 lb wheels for example

 

You basically are completely full of crap. You might turn a wrench here and there but many of your assumptions on what makes cars fast or what makes cars have more WHP are completely wrong.

To say that rotational mass has no impact on WHP is absolutely absurd. Rotational mass has an enormous difference on WHP. Adding bigger brakes (not "breaks") adds rotational mass if your rotors are larger and will make your car have less power and be slower. Adding heavier rims and/or tires will do the same, as will adding a heavier driveshaft or heavier flywheel.

Think about it..... if you had giant cylindrical lead-filled forms that were the same size and shape as your stock rims and tires but weighed like 400 pounds each, your car would obviously dyno much lower in Wheel Horsepower than the stock setup. Anyone with an ounce of experience on dynos knows this to be true. It doesn't add horsepower... but it reduces the amount of crank horsepower lost when doing a rolling wheel dyno.