Author Topic: SAI Delete - Research so far...  (Read 13870 times)

RC81

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Re: SAI Delete - Research so far...
« Reply #40 on: 27 October 2016, 18:09 »
It's interesting to hear you say how your 1.8T runs with the EVAP system removed but with no Resistors and and a few loose hose connection's. I'd expect that to be fair. The true test is how it runs, drives and passes emission's when it's all finished?
As for the SAI system, god know's why VW created that. All I see it as is a whirring pump that get's in the way when going to remove the oil filter! lol.
But more seriously, I want to remove thing's that aren't necessary, such as the SAI. But I'm more nervous to touch the N249 etc without seeing it done on another car. I've read so many stories on the subject, but with no final outcome of how it actually runs emission's wise. Hopefully you can solve that one??

Plus with the AGU being a cable throttle and different ECU setup to the AUM being the opposite, i'm sure other's such as Wazzer can help on that subject??

Oh and I can't find the plug's you found....

Offline OSR

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Re: SAI Delete - Research so far...
« Reply #41 on: 27 October 2016, 18:29 »
Yeah I have read the emissions are ok at least on the Drive by Wire cars (AUM/AUQ) and the main purpose of the resistors is to make sure the adaptive fueling ("fuel trims") are functioning correctly. I don't think, but would like to prove, that simply removing any of the systems themselves causes a CEL, they just give a hidden fault code that may or may not affect fueling. The main difference with the SAI pump is that the CEL will come on after an undefined number of the car attempting to fire the pump up and not seeing what it expects at the Lambda sensor. In short it's the lack of function not lack of presence that causes the issues from my understanding...

I'll find you a link to eBay later on - they come up under something really obscure!

As for the N249 - I actually bypassed that years ago but left it plugged in to keep the ECU fooled. Can't recall noticing any major difference at the time but I wasn't even Stage 1 mapped at the time, it was more in preparation for the map and also to get rid of all the OEM junk breather pipes that had split and fit a catch can. Two of my resistor packs are for the N249 and N112 so I'll take some photos and show you what I've done there as part of this whole SAI thing - hope that helps?
« Last Edit: 27 October 2016, 19:45 by OSR »

RC81

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Re: SAI Delete - Research so far...
« Reply #42 on: 27 October 2016, 22:40 »
Having read a few posts on VW Vortex and Audi-sport.net, the subject comes up very often, but having your input certainly helps. My other question is, that with the SAI removed does it effect the pre-cat Lambda reading's at least when the cars cold, running rich? So once the car is up to to full temp the SAI is then redundant.

But if you can find the ebay link to the correct connectors, that would be great, I've scoured eBay and I can't find them. I fancy making up some like yours for when i first remove the SAI.

As for the N249 valve, my only concern is that the ECU is no longer controlling boost pressure with it's removal. But also gets very mixed reactions on forums. But you've said you noticed no difference there. So as I've also read, no two cars get the same outcome it seems.
I'll be interested to see more pic's when you get the chance to upload them

Offline OSR

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Re: SAI Delete - Research so far...
« Reply #43 on: 28 October 2016, 13:44 »
Here you go mate;

http://www.ebay.co.uk/itm/Wholesale-Kits-Car-Boat-Electrical-Waterproof-Connector-1-2-3-4-5-6-Pin-Way-Seal-/152003634379?var=&hash=item23641f64cb:m:mmFO_nnJkIsvkDF0g1Fgz7w

With regards to running rich I would assume that the fuel trims etc adapt so its not really an issue? I've got a Milltek sports cat on mine so still have the pre-cat sensor fitted, I think if you fit a decat you have to have the sensor mapped out so it doesn't throw a fault.

The SAI pump runs for the first 30-90 seconds or thereabouts after start up and it's the incorrect flow (i.e. lack of fresh air) through the exhaust system on startup that causes the CEL. It's function is to protect the CAT but once this initial few seconds has passed the SAI pump is redundant so can't see an issue come MOT time as by the time you're at the testing station the car should be warmed up in any case. I'm not, as I don't think many are, that the SAI actually does protect the CAT, and if it does, I'd rather not have it and replace the CAT slightly early if it came to it.

Offline lemski

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Re: SAI Delete - Research so far...
« Reply #44 on: 29 October 2016, 10:24 »
With regards to the n249, every customer ive done it for who wanted it it has let the boost hold better and in my oppinion made the car better to drive

RC81

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Re: SAI Delete - Research so far...
« Reply #45 on: 30 October 2016, 10:56 »
With regards to the n249, every customer ive done it for who wanted it it has let the boost hold better and in my oppinion made the car better to drive

That would explain why when i'm at full boost. Was 1.2 bar, now it's 0.8 bar for some reason, the reading fluctuates very slightly. Doesn't stay solid so to speak. My N249 threw up a code a few weeks back but I cleared it due to just replacing all the vac hoses and dipstick tube. So my N249 could be playing up? Still need to see why I'm boosting at 0.8bar. My Golf is supposed to be mapped by AMD a few years back.

But if the N249 was to be removed, does it help if the ECU has been re-mapped, ie not running a stock map? 

Cheers
« Last Edit: 30 October 2016, 10:59 by RC81 »

Offline lemski

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Re: SAI Delete - Research so far...
« Reply #46 on: 30 October 2016, 13:10 »
You can bypass either way. Doesnt matter. Most people keep them plugged in but simplify all the vac system. excluding the n75 connections
If you want to know its inlet to fuelpressure reg
Inlet to recirc valve
Im sure theres another. Im off to look at a s3 ive done it to later so ill check as its the same to simplify it

RC81

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Re: SAI Delete - Research so far...
« Reply #47 on: 30 October 2016, 21:23 »
I'm still reading up on the routes on which hoses to keep & loose. I've read a few various posts on the subject. Some good one's, some bad etc. This thread certainly helps  :smiley:But now it's making more & more sense.
I found this thread the other day on Audi-Sport.net
http://www.audi-sport.net/xf/threads/sai-removal-guide.88299/

But it would be nice to simplify things under the bonnet just to aid working on the engine from time to time. I've still got to repair the coil pack looms on mine, wires are starting to split.
Was going to order this:
http://www.psituning.com/product.php/21413/genuine_coilpack_wiring_loom_replacement_1_8t_cars_with_oil_level_sensor

Any more info would be great


Offline OSR

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Re: SAI Delete - Research so far...
« Reply #49 on: 31 October 2016, 09:19 »
No worries, glad I could help. I fitted them to the car at the weekend and have a load of photos. I would say that fitting the female plugs to the car harness was a pain - one wire to each existing plug is only like 0.5mm versus the other which is 1.5mm (what the terminals on the new connectors is designed for). Because of this relatively weak crimp (even with the wire twisted and doubled back on itself) when installing and shifting everything around they have a tendandcy to come loose. I gave up on one after wrecking the connector and just connected the terminals together and covered in black elec tape!

It took me literally years to convince myself to remove all of this stuff but I'm glad I did - loads simpler in the engine bay now and less to go wrong!