Throttle body tuning

Vark wrote:Back again!
At last I found a throttle body from a NG motor at the local scrap for 70e, so tomorrow I was of putting it on.

So Skull, before I take the big step I have one last question (sorry for asking over and over but, I'm a student so the 70 means to me ) have you faced any problems running on idle or any general instability on rpm? I'm just asking because I can't understand how engine manages the extra air if the ECU does't know and is ratio of mixture right?

thanks in advance for once more

That's why you have a oxygen sensor(lambda). It measures the Air/fuel ratio and gives signal to the ECU ECU regulates then the amont of fuel. I've seen this been done on some other cars, and it worked just fine. I think you will notice the engine revs faster with this mod.

no problems with the ng throttle body.

the other fun thing is, that the ace has a potentiometer, the ng only have the minimum (idle) switch and the full throttle switch, but still the engine runs perfectly without the potentiometer...

$küll wrote:no problems with the ng throttle body.

the other fun thing is, that the ace has a potentiometer, the ng only have the minimum (idle) switch and the full throttle switch, but still the engine runs perfectly without the potentiometer...

TPS (throttle position sensor)? Now thats weird. On newer engines the ECU will go into emergency mode if the TPS doesn't work properly. I don't know with the ACE-ECU. Have you checked your AFR?

what is AFR?

$küll wrote:what is AFR?

Sorry, I'm used to short terms..

Air-fuel ratio (AFR)

Maby you can read the values with VAG-COM.

aha, no i didnt check, but the car is going really well. both HP an NM raised very much from stock with all the mods i have made. maybe is should add some fuel to the mixture, i had the MOT (technical check @ registration) last week, and the co2 readings were a little high, but it passed even with the sport cat.

hi,today im to change throttle with im I bought fore 8 euro and what you now is fill the difference in power ,(but sometimes feel that funds mixture ) it is like having one passenger less in the car,im use throttle from 2.3 20v 7a engine his better is hawe idle which can be adjusted manual and potentiometer ,speciali when original idle stuck, and my idling from 1500-2000rpm

this is smal mod
without the walls of the throttle, and the pedal was more sensitive .

good job!

Hi everyone!
I tried this throttle body mod today. I replaced the ACE's tb to the NG's tb.
Idle speed raised to 2000 rpm and when i took test drive idling was around 3000 rpm. When i unplugged the ISV connector idling was about 1500 rpm.
I think the problem is the lacking of potentiometer? I also have 7a's tb, I didin't try it because the potentiometers connector is two pin connector and ACE's is three.
I'm sorry for the bad english but ask if you didin't understand

hello.

it is certainly not an issue of the potentiometer, because i tried 2 different 5cyl throttle bodies, and the engine runs perfectly with both of them.

the only problem i can think of is some air leak, maybe you didnt connect the pipe that goes to the throttle body, or maybe the most plausible one, that you have a screw in your throttle body, that the NG engine uses to set the idle.

you can see where the idle screw is on this pic, on the rights side, it is in the upper aluminium pipe:

Ok
Today I tried again and I closed the idle screw, and idle sets to little above 1000 rpm. I noticed that acceleration cable was too tight, and throttle wasn't fully closed
ISV dosen't work properly because when I unplugged it the idle is perfect. New ISV will arrive next week.

I still wonder about the potentiometer. What is the benefit if the car runs perfectly with out it?

p.s thanks for the tips

i dont know why it is working ok without, but i have an extra compi throttle, and i will try to open the box, to see if it regulates the inmpendance or it just replaces the idle and wide open throttle switches.

NEWS!

In the last week i was thinking how could i attach the potentiometer of the original compi throttle body to the 5 cyl throttle. the box is too big to install under the 5cyl throttle body, because i have the 5 cyl exhaust manifold, and installing it on top would take some mechanism, so it turns the right way around.

I could not find a fast solution for it, so i decided to sacrifice a potentiometer, so i planned to open it up, and see if the mechanism inside could be modified to fit on top of the throttle body...

but then i opened it...




THERE IS NO POTENTIOMETER!!!!

there is the idle switch, and for the WOT (wide open throttle) two pieces of metal just touch each other.

this is a really retarded design, totally useless, and very deceiving.

so bottom line is, the 5 cyl throttle body with 3 pin connector and so with 2 switches (WOT on top, idle on bottom) will work PERFECTLY on our engines!

this is the throttle body i use





i have modified it, so in the place of the idle screw there is the pipe that goes to the airbox.

iv choosen this throttle body because it has the less springs and mechanisms on the bottom, so it is far from the exhaust manifold.

the bad point of this throttle body is that it has no damper, so when you release the gas pedal, it closes the fuel very fast, and if you want to accelerate fast, this is quite bad, as you really need to keep the gas pedal pressed when shifting gears. i will try to add the damper to it. as it keeps the throttle open for a little time.

the throttle on the left is the 5cyl engine with 2 switches that works pefectly for cars with stock exhaust manifold, just plug and play.



you can see how much more air flow capabilities it has compared to the stock throttle body.

i think because of more air getting in the engine, it would be good to reset the injection to a little more fuel.

this is the interior of the "potentiometer"


Idle position
you can clearly see the grey idle switch in the top right corner, you can see the crome brace touching the micro switch.



WOT position
bottom right you can see thw copper contacts touching each other

MYTH BUSTED!

Hello,
I replaced the ACE's tb to the NG's tb.
Conected ISV car wond work. It s like wrong air/fule mixture. Car works like Subaru.
But unplugged ISV car works well but idle is about 1500p.
What can be the problem?
Sorry about bad english.

hello.

first of all i would suggest you post a pic of the throttle body, because the NG had different TB`s.

the first thing i would check is if the idle switch works, and if it is turned on when you release the throttle,maybe it is set wrong, or maybe your throttle cable is too tight, and doesent allow the TB to fully close, like it happened to our friend harhamo on page 2 in this thread.

second thing, did you connect the vacuum pipe right? no leaks?

this is how i have the cable set on my compi. maybe you wont need to set is so furter to the right, as my TB is heavily modified from 3 different TB`s because of the exhaust manifold.



just be sure the cable is not tense when the pedal is released, and that the throttle body triggers the idle switch. you can clearly hear the "click" when it does, so it is easy to know. (with engine turned off).

I use this trottle.

damn, this is not the throttle body you want, because it has no wide open throttle switch on top.

this is the throttle body i used before my current one:









this is the WOT switch



this is the idle switch



the throttle damper is missing, and also the throttle cable lead on top is missing...