[The Mailman 666]

What exactly does porting the cylinder head do? And would it be worth it to do it to a mostly stock engine?

How much could one expect to pay to have this done?

 

[aero_student]

no, it's not worth it all until you build the motor. the stock cylinder head is exceptional.

 

[The Mailman 666]

no, it's not worth it all until you build the motor. the stock cylinder head is exceptional.

What is this? "Tumble flap delete"

Can I assume that this is what gives my car a sudden burst of power after 2800-3000RPMs? I also assume it is designed to give the car better mileage at low RPMs? I hate it! How do I fix it?

 

[aero_student]

Sorry, studying for a final tomorrow. do a search over on focaljet.

 

[metallicnotazx5]

the tumble flaps are a good thing....

they change the length of the intake runners.
long at low rpms
short at high rpms

it gives for a much more even torque band

basically it is time to get rid of the tumble flaps when you build your engine to rev over 6,800 rpms and then you should just go with a cosworth intake manifold

 

[The Mailman 666]

the tumble flaps are a good thing....

they change the length of the intake runners.
long at low rpms
short at high rpms

it gives for a much more even torque band

basically it is time to get rid of the tumble flaps when you build your engine to rev over 6,800 rpms and then you should just go with a cosworth intake manifold

That may be so but my car jerks on the power at around 2900rpms. If I shift just after the power hits it feels very jerky for any passangers in the car..

 

[metallicnotazx5]

That may be so but my car jerks on the power at around 2900rpms. If I shift just after the power hits it feels very jerky for any passangers in the car..

what do you mean jerks.... at thoes rpms you are starting to get into peak power......

your posting confuses....

don't take the tumble flaps out til you make over 170whp or you want to rev higher than 6,800...

and the tumble flaps would not cuase your car to be "jerky" if anything they would cuase the car to be smoother

you have a throttle body don't you? that is probably the cuase of the "jerking"

 

[Egz]

the tumble flaps are a good thing....

they change the length of the intake runners.
long at low rpms
short at high rpms

it gives for a much more even torque band

basically it is time to get rid of the tumble flaps when you build your engine to rev over 6,800 rpms and then you should just go with a cosworth intake manifold

Wrong.

What you described was the variable runners. Tumble flaps operate at low RPM to create a tumble in the airflow to aide in air/fuel mixing for better emissions. When they are off, they are still an obsticle in the airstream, so by removing them, you sneak out a little more airflow from the manifold.

 

[metallicnotazx5]

Wrong.

What you described was the variable runners. Tumble flaps operate at low RPM to create a tumble in the airflow to aide in air/fuel mixing for better emissions. When they are off, they are still an obsticle in the airstream, so by removing them, you sneak out a little more airflow from the manifold.

tampering with emissions ......


check.. lol how much air flow 1cc?

 

[The Mailman 666]

Wrong.

What you described was the variable runners. Tumble flaps operate at low RPM to create a tumble in the airflow to aide in air/fuel mixing for better emissions. When they are off, they are still an obsticle in the airstream, so by removing them, you sneak out a little more airflow from the manifold.

So how do I fix my dead engine below 2900 RPMs.

 

[metallicnotazx5]

So how do I fix my dead engine below 2900 RPMs.

that is a function of a power band then. my car feels like a turbo kicks in at about thoes rpms, i've had people ask me if i have one cuz of the power band and the whistle from the cai

 

[The Mailman 666]

that is a function of a power band then. my car feels like a turbo kicks in at about thoes rpms, i've had people ask me if i have one cuz of the power band and the whistle from the cai

Man do you even know what the term "power band" means? Because i don't think you do. Please go ahead and explain your "power band" answer. Oh and just so you know I own a CBR900RR and know all about power bands and what they are. Trust me when i say that the boost in power around 2900RPMs is in part caused by something mechanical in nature. For one thing the power does not always hit at the exact same place in the revs. I’ve had it hit as early as 2500RPMs and as late as 3200RPMs so it is not solely based on RPMs. If I step on it from low revs I can get it to hit around 2500RPMs if I baby up the revs It will hit softly at 3200-3300RPMs. That is not how the power band of an engine works. Just in case you didn’t know a power band is not an “object”.

 

[metallicnotazx5]

mailman, you are confusing the living hell out of me

 

[whynotthinkwhynot]

So how do I fix my dead engine below 2900 RPMs.

Get an SCT XCal2 from Hypnotic or Marcy. The standard tunes should help you out. I've found on my D20 that -2 ignition timing helps maintaining low speeds in tall gears. I'm not sure if that will help D23's or not.

The reason your power band seems to be moving around is because the computer is changing ignition timing, A/F ratio, and fuel pressure constantly depending on what you're doing. This is not a bad thing, but I think that's what's causing what you're feeling. Keep in mind also (from what I remember) that all the mods you've done so far have been to increase high end hp (like the TB) and without changing the cams or adding a turbo most anything that increases top end will decrease bottom end.

You're not about to go postal are you?
[lol]

 

[metallicnotazx5]

focussport tunes >*

 

[FocusFreak87]

^^^That's where im getting my Xcal 2 from...

 

[metallicnotazx5]

^^^That's where im getting my Xcal 2 from...

good man.

i hate to knock macry and wayne but the problem with them is, htat is their side jobs, and marcy has pretty much shut down...
but randy and his crew at focussport work on focus all day and everyday.
Doing installations, cam tunning, dyno tunning wokring with cosworth etc. etc....

that is why i perfer focussport for tuning than anyone, and ebcuase they have awosome suport if something does go wrong.

 

[whynotthinkwhynot]

I'm sorry I didn't think about FS. I was trying to list all the FF vendors that had XCal's for sale. [duh]