yourmom23

iTrader: (4)

Wondering what rpm everyone sets there idle to on there street port. Mine sits about 900 right now and is a bit lumpy. I think i am going to bump it up to like 1100 or 1200 seems smooth there. Oh my mods are pettit ecu 3 all the way back, medium street port, 2mm seals. Let me know what you guys run

catch-22

iTrader: (2)

i do 1100 on mine, if i go any lower it doesnt like it too much. This is with a holset WH1E, 4in exhaust and large streetport.

bajaman

I've got a moderate street port and it runs 800 rpm without sounding too far off from stock.

yourmom23

iTrader: (4)

4in exhaust holy crap thats got to be loud as ****

jmadams74

Full street port; 820; perfectly smooth

bzwigart

iTrader: (9)

mine seems happy at 1000

CrispyRX7

iTrader: (139)

1000 with 850cc primaries.

Crispy

IRPerformance

iTrader: (41)

I like it between 900 and 1000 with a decent-sized port. A lot of it is in the tuning but if the car idles too low it will be more prone to stalling.

GoodfellaFD3S

iTrader: (213)

A lot of it has to do with your vacuum, the car won't idle much below 12 inches (-300 on pfc commander) or so.

Guys idling at 800 rpm smoothly don't much a very large streetport. Nothing wrong with that, but most larger SPs will idle nicely at 1000 to 1100 rpm.

As crispy alluded to, the size of the primary injs makes a difference.

My fresh SP idles at 1050 rpm with a nice 4 inch full exhaust, it sounds mean

catch-22

iTrader: (2)

lol just a tad bit

yourmom23

iTrader: (4)

I think mine being so lumpy is probly due to the stockish ecu. Montana open roads good, no one knows jack about tuning or rotories bad. Anyone want to come visit montana to tune my car.... i have beer....

carbonfaddict

1000rpms with stock primaries and 1600 up top on a large SP also running a 4" exhaust. People tell me they love the sound...I can't take it. I'm looking for a decent quiet exhaust now.

GoodfellaFD3S

iTrader: (213)

All you guys with 4 inch exhausts.....

Run an Apex'i GT Spec (or N1) with the Apex's ATS/Active Tailpipe Silencer. It's springloaded so you get the best of both worlds. I'm on engine break in so am keeping it installed. Time to dyno, arrive at the track, etc, out it goes

http://www.apexi-usa.com/products/?id=5327

theorie

iTrader: (31)

mine seems to like to sit right at about 1000-1050ish

street port, 3mm mazda apex seals, 550 pri / 1600 sec

johgar

iTrader: (21)

Can anyone help me?
Street-port, 750cc primary. I have very lumpy and low idle. Still on break-in right now. Sometime idle as low as 500, sometime will stall.
Almost same setup as before the street-port, just replace with bigger intercooler. Will intercooler make any difference and causing low idle? Didn't change anything else. It run good when cruising.

Daniels

GoodfellaFD3S

iTrader: (213)

Use your throttle body adjustment screws to raise the idle.

johgar

iTrader: (21)

OK. Going to try that tomorrow. Thanks.

Uncle Hungry

iTrader: (2)

I have a pretty aggressive street port with a good amount of overlap and I can idle at 900 rpm, but I keep at at 950-1000.

hwnd

iTrader: (4)

large street port idled @ 800/900 rpms. smooth as stock.

the flywheel has *major* affects on a smooth/rough idle, not just port-sizing.

smog-guy707

iTrader: (11)

+1

arghx

iTrader: (3)

I've got a large streetport, 2mm seals, and a lightweight flywheel. I recently ported the exhaust with the Pineapple Racing EP3 template, which bevels them down below the exhaust sleeve. Engine only pulls between 290-320mm vacuum (high 11 to mid 12 inches). What I have found is that with the ISC valve installed and Power FC idle ignition control on, the engine idles much better even with such a weak vacuum signal. This is why I have lately been encouraging people to keep the ISC installed. When it works as the factory intended the idle quality is much improved at a given rpm.

In these logs I have my ISC installed and Idle IG control on. Engine vacuum isn't displayed but it is only around 300mm. I am idling just below row P6 whereas most people are closer to P4 because they have more manifold vacuum.





Notice how I don't need to be running 12,15, or even 20 degrees of leading timing advance? That's because of the ISC. I used to run 20+ degrees at that idle speed with the ISC deleted and idle timing manually controlled. And that was without an electric fan running. Believe it or not, the parts of your engine and ECU that were designed to stabilize idle do in fact stabilize idle with very little fuss once configured correctly.

WaachBack

iTrader: (21)

1300

Banzai-Racing

iTrader: (11)

As long as you have the ability to tune (PFC etc), there is no reason that an aggressive streetport will not pull 14-15 vacuum and idle at a smooth 800-850 rpm. If your car wont maintain an idle lower than 1100 rpm there is something wrong with the tune/engine, it does not matter how large the streetport is. However if it is bridgeported it will pull weak vacuum and need to have the idle bumped up to keep it from stalling.

Our 13b-re has a huge streetport, pulls 15 vacuum and idles at a glossy 800rpm

We would never let any customer's car out of our shop with a 1100 rpm idle on a SP engine

GoodfellaFD3S

iTrader: (213)

Good point, most cars that I see nowadays have a light flywheel on them which makes for a less smooth lower rpm idle.

Arghx, thanks for posting those logs. Come to think of it I've been focused on so many other things on my car, I have to go see if I have the ign idle control enabled or not.

Mahjik

iTrader: (1)

With a stock based rechipped ECU like the OP, the idle is going to need to be higher without the airpump regardless of the port. Removing the airpump on a stock based ECU makes the car run richer at idle and is very unsteady at the stock 750-850 rpms. Increasing the idle rpms since you have you don't have a way to adjust the ECU will help smooth things out.

yourmom23, raise the idle to around 1100 rpms for your setup and you'll be fine.