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Idle after Full Exhaust

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Old 04-29-08, 03:55 AM
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Idle after Full Exhaust

this past weekend i put on full turbo back exhaust (dp, mp, rb catback, with restrictor plates). since i am not running a midpipe i dissconected the airpump. because the airpump is unpluged, now the idol is all screwy. i know i need to raise the idol to 1100-1200rpms or so to get it to run clean and steady.

the thing i am confused about is adjusting the TPS. i read a how-to on re-setting the TPS, but i dont believe that will get me the idol i want. do i just adjust one of the bleed screws? should i set it using a higher voltage reading?

also, is it possible that for now i could keep the airpump pluged in and have it just venting air from under the car?
Old 04-29-08, 04:29 AM
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please tell me you're running an aftermarket ecu. if so, you can check the tps voltage to see if it's within tolerance.


"idle" not "idol"
Old 04-29-08, 04:30 AM
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Your car will run like crap if you disconnect the airpump with the stock ECU.

You shouldn't be running a midpipe anyway, put a cat back on. Restrictor plates don't do dick, regardless of what the guy that makes them says.
Old 04-29-08, 07:46 AM
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please tell me you're running an aftermarket ecu. if so, you can check the tps voltage to see if it's within tolerance.
just to let everyone know...i am still running the stock ecu! therefore i cant just "check the tps voltage".

Originally Posted by SLOASFK
Your car will run like crap if you disconnect the airpump with the stock ECU.
i already have come to that understanding. your pretty much putting in short what i first posted...

i know what i need to do regarding the airpump elimination. i just dont know "how to do it".

You shouldn't be running a midpipe anyway, put a cat back on. Restrictor plates don't do dick, regardless of what the guy that makes them says
i dont mean to be rude, but please dont give me advise if you dont know what your talking about. if you can give me some proof or credibility to your statment, then please do. i understood what i was doing when i dumped the cats.

i also made my own restrictor plates; they work quite well and havnt been any trouble thus far. i am just stumped on the tps situation.
Old 04-29-08, 08:26 AM
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He does know what he is talking about. You shouldn't be running full exhaust on a stock ECU. Restrictor plates or not.
Old 04-29-08, 08:54 AM
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You don't need to adjust the TPS to raise the idle, just use the adjustment screw on the throttle body to raise the idle.
Old 04-29-08, 12:07 PM
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Originally Posted by drew32
He does know what he is talking about. You shouldn't be running full exhaust on a stock ECU. Restrictor plates or not.
Umm...why? What's wrong with running full exhaust on a stock ECU? The stock ECU won't compensate for the increased airflow on its own?

<-- Total FD noob
Old 04-29-08, 12:09 PM
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Originally Posted by RMRanger
Umm...why? What's wrong with running full exhaust on a stock ECU? The stock ECU won't compensate for the increased airflow on its own?

<-- Total FD noob
Nope. The FD uses a MAP system. It's a pre-programmable fuel map which doesn't self-adjust. The original poster will be fine if he is able to keep his boost at 10 PSI or below.
Old 04-29-08, 01:19 PM
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Ahh that's right. I had read somewhere before that FDs don't have MAF sensors but I forgot. At any rate, the car isn't supposed to boost past 10psi on the stock map, right?

Also somewhat related, does the fact that it has a MAP mean that I'll have to have a car I'm looking at buying retuned for high altitude? I doubt it ever was...
Old 04-29-08, 01:23 PM
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The stock map has plenty reserve for most anything at 10 PSI (including any difference altitude can make). FWIW, you cannot adjust the stock ECU. You have to change it out to a programmable ECU like the Apexi Power FC to make any adjustments.
Old 04-29-08, 01:45 PM
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Originally Posted by SLOASFK
Your car will run like crap if you disconnect the airpump with the stock ECU.

You shouldn't be running a midpipe anyway, put a cat back on. Restrictor plates don't do dick, regardless of what the guy that makes them says.
mine ran fine without the airpump?
the bearings died out pretty quick so i just unplugged it. ran fine.
Old 04-29-08, 05:59 PM
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Originally Posted by Mahjik
You don't need to adjust the TPS to raise the idle, just use the adjustment screw on the throttle body to raise the idle.
where is that. if anyone would have a diagram or a picture of where the adjustment screw is..that would be fantastic
Old 04-30-08, 02:32 AM
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I was hoping you were running an aftermarket ecu b/c I don't want you to blow your motor with a full turbo back exhaust.

drew and sloas are both correct. thin ice, imo
Old 04-30-08, 05:24 AM
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Originally Posted by grimple1
I was hoping you were running an aftermarket ecu b/c I don't want you to blow your motor with a full turbo back exhaust.
full exhaust on the stock ecu doesnt blow motors, increase in boost does. i understand your concern, but its not needed

drew and sloas are both correct. thin ice, imo
if you know so much, why dont you explain to me where i went wrong.
Old 04-30-08, 06:11 AM
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Originally Posted by 4CN A1R
full exhaust on the stock ecu doesnt blow motors, increase in boost does.
but running full exhaust removes any restrictions to the exhaust flow and the stock wastegate can't keep up with it causing boost creep unless you have a ported wastegate. u should at least have a boost gauge to monitor (granted you will never be able to run WOT for more than a few seconds without your boost will creeping past 10psi). i think you should be fine even with the boost creep since the stock ECU does compensate up to a certain pressure (i think 15psi) until it cuts off fuel which will increase chances of detonation. just be careful and i suggest getting a high flow cat since it eliminates that boost creep. btw the idle adjustment screw is located on the drivers side of the throttlebody under the elbow towards the rear. use a flat screwdriver to adjust. i think turning it clockwise lowers idle and vise-versa. haven't touched mine in awhile
Old 04-30-08, 07:55 AM
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Originally Posted by 4CN A1R
full exhaust on the stock ecu doesnt blow motors, increase in boost does. i understand your concern, but its not needed



if you know so much, why dont you explain to me where i went wrong.
Its not that i know so much, its that it has been proven again and again that running full exhaust on a stock ecu without a ported wastegate is dangerous. You need at least a boost gauge to monitor your boost. Also remember that your boost can increase the colder it is outside so driving this car in the winter will be even more dangerous. If i were you i would have my wastegate ported, that way you can keep the stock ecu and not have to worry so much about boost creep or boost spikes.
Old 04-30-08, 08:10 AM
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Originally Posted by RotaryBred
but running full exhaust removes any restrictions to the exhaust flow and the stock wastegate can't keep up with it causing boost creep unless you have a ported wastegate. u should at least have a boost gauge to monitor (granted you will never be able to run WOT for more than a few seconds without your boost will creeping past 10psi). i think you should be fine even with the boost creep since the stock ECU does compensate up to a certain pressure (i think 15psi) until it cuts off fuel which will increase chances of detonation. just be careful and i suggest getting a high flow cat since it eliminates that boost creep. btw the idle adjustment screw is located on the drivers side of the throttlebody under the elbow towards the rear. use a flat screwdriver to adjust. i think turning it clockwise lowers idle and vise-versa. haven't touched mine in awhile
15psi? the fuel system can only handle 13psi of boost, hence why the stock ECU is only good up to 12psi.
Old 04-30-08, 09:52 AM
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Guys, if he's able to keep the boost at 10PSI or below, the stock ECU has enough fuel at those levels to support the increased CFM from his mods. So far the most I've seen dyno'd (recorded on this forum) was 266rwhp from full bolt-ons (including midpipe) on the stock ECU. IIRC, the owner removed the pills from his boost lines which allow the car to boost creep from about 7PSI to just under 10PSI.

Using restrictor plates should keep his boost in check. However, he'll have to be careful as the weather gets cooler again and make sure whatever size restrictor his is using will be ample to keep boost under control in the cooler weather conditions.


Sorry, I forgot to take a picture last night. Here's a shot of the adjustment screw. Start your car, use a 8mm open wrench to loosen the nut. Turn the screw with a screw driver until your idle evens out, then tighen back up the bolt with your 8mm wrench.
Attached Thumbnails Idle after Full Exhaust-adj_screw.jpg  
Old 04-30-08, 12:48 PM
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Originally Posted by RotaryBred
but running full exhaust removes any restrictions to the exhaust flow and the stock wastegate can't keep up with it causing boost creep unless you have a ported wastegate. u should at least have a boost gauge to monitor (granted you will never be able to run WOT for more than a few seconds without your boost will creeping past 10psi). i think you should be fine even with the boost creep since the stock ECU does compensate up to a certain pressure (i think 15psi) until it cuts off fuel which will increase chances of detonation. just be careful and i suggest getting a high flow cat since it eliminates that boost creep.
i think its funny you all act as if i just got the car, or that i know nothing..? i stated many times throughout the thread that i just wanted an answer to my question. i didnt ask for a debate or a long drawn out discussion. i have a boost gauge, i have a boost controller, i carefully monitor and control my boost keeping it a 10psi

btw the idle adjustment screw is located on the drivers side of the throttlebody under the elbow towards the rear. use a flat screwdriver to adjust. i think turning it clockwise lowers idle and vise-versa. haven't touched mine in awhile
thanks. though the screw mahjik pointed out seems to be in a different location...
are you sure your not talking about the tps adjustment screws??

15psi? the fuel system can only handle 13psi of boost, hence why the stock ECU is only good up to 12psi.
its acutally only good up to 11psi. going over that can result in fuel cut and ignition break up
Old 04-30-08, 01:47 PM
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Originally Posted by 4CN A1R
its acutally only good up to 11psi. going over that can result in fuel cut and ignition break up
well then you might want to tell majik to fix the FAQ and i doubt he would wanna do that looks like he spent alot of time on it

"31) How do I turn up the boost?

Allowing the stock system to run above 11psi is not advisable without modifying the stock ECU, since it isn't programmed to respond to boost above 12psi. As well, the fuel system is limited to 13psi. Once those systems are upgraded, boost level can be controlled by installing an electronic boost controller, a manual boost control valve, or installing a pill with a smaller orifice. BOV settings do not affect working boost level. For smaller increases in boost, the PFC and other tunable ECUs allow adjustment of boost using the stock wastegate components, however at higher boost levels this is not advisable due to limitations of the stock wastegate solenoid and actuator."
lol


Originally Posted by 4CN A1R
thanks. though the screw mahjik pointed out seems to be in a different location...
are you sure your not talking about the tps adjustment screws??
there are 2 "idle adjustment screws" (take that term loosely) the true adjustment screw IS located on the botton of the throttlebody under the elbow its horizontal, but as a last resort, and it is highly not recomended you can adjust the throttle limit screw which limits how far the butterflies are able to close thats just forward of the throttle body and is vertical
Old 04-30-08, 02:28 PM
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its acutally only good up to 11psi. going over that can result in fuel cut and ignition break up

Allowing the stock system to run above 11psi is not advisable without modifying the stock ECU, since it isn't programmed to respond to boost above 12psi
please tell me the difference between these two statements


Originally Posted by RotorDream
well then you might want to tell majik to fix the FAQ and i doubt he would wanna do that looks like he spent alot of time on it

As well, the fuel system is limited to 13psi.
another thread displays fuel cut levels. thats what i was referring to..mahjik was speaking of 13psi as a rounded number. at certain rpm ranges you can hit fuel cut before 11psi.
Old 04-30-08, 03:09 PM
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I think we're all only trying to make sure this doesn't end up with a "time for rebuild" thread.
Old 04-30-08, 04:17 PM
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Originally Posted by Mahjik
You don't need to adjust the TPS to raise the idle, just use the adjustment screw on the throttle body to raise the idle.

Could you show me a picture of this ? is it under the throtle body or on top?
Old 04-30-08, 04:21 PM
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Originally Posted by wb123
Could you show me a picture of this ? is it under the throtle body or on top?
I just posted the picture a few messages up.
Old 04-30-08, 05:07 PM
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4CN A1R is not exactly a newb here boys. however he has helped many of the newbs on the forum.

Adjust the screw under the elbow (horizontal) not the one on the front of the
TB (vertical). when your done that go buy a power fc so the concerned members of the forum dont worry about u. haha


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