WTB: an experienced technicians help

**4seasons69** · 08-07-2008

ok so I'm having a hard time getting my car running right. I have a 1990 eagle talon tsi awd. my main issue is I get a lot of knock on little amounts of boost. I've already done a lot to help suppress it I'm running 1 range colder plugs, fmic, 650cc injectors, afpr, walbro 255lph fuel pump, I always run 92 octane, and I have fixed a lot of boost leaks. I'm not sure if I still have leaks I can't find or if it's a tuning issue or what. when I put race gas in the knock dissapears then when I turn the boost up to 12psi it starts to knock again
so I'm looking for someone that has a lot of expierence with these cars preferably with some tuning experience that would be willing to help me out. and yes there will be compensation for your time. let me know if any of you are interested. thanks

-shawn

95talonracer · 08-07-2008

What is your base timing set at?
Also do you have a wideband?
What do you use to tune?

**4seasons69** · 08-07-2008

I haven't checked my base timing yet. I don't have a timing light. and also no wideband yet either but that is the next thing I'm going to get when I can afford it. as for tuning I'm using an safc2 and a 3"gm maf and maf-t and a data logger using mmcd. I have the safc zeroed out right now and have been trying to get a base tune with the maf-t then fine tune with the safc

95talonracer · 08-07-2008

Where are you located? You should first check the base timing and then get a wideband or dynotune the car so you know what is happening when you change the settings on the safc. You dont know what you are really changing when you dont have a wideband (either in your car or on a dyno) with the safc.

**4seasons69** · 08-07-2008

I live in circle pines. by lake drive and lexington if you are familiar with the area. I don't know how to check or set the timing. I'm still learning some of this stuff. I've been watching my fuel trims and knock on my data logger. I'm working on the wideband but as for the tuning I know I need it dynotuned but in a month or two I'm going to have the head rebuilt and cams put in so I don't want to pay to have it tuned then pay to have it tuned again in a month or two. I just want to get it running decent so it doesn't go kaboom before then

**Shane@DBPerformance** · 08-07-2008

It's going to be hard to tune without a wideband. Fuel trims don't help full throttle and stock O2 volts at full throttle are not consistant at all throughout the RPMs. Base timing is critical though, if it's way off, that could be your main problem. The 650s are also going to make you more likely to knock than 550s or 450s also.

95talonracer · 08-07-2008

But to have a SAFE base dyno tune now to save your motor until you get your new parts and retune later is much better then saving a few hundred now and wrecking something (engine) because you are trying to tune it without and source of telling you what you are changing. I would almost put it to stock and do not push boost until you first set base timing and second tune it with a wideband. Good luck. Alot of us have learned the lesson the hard way and we are just trying to save you some $ in the end.

**4seasons69** · 08-07-2008

I can't put it back to stock I'm running a bigger turbo cause my 14b was junk. I appreciate the help. just a little curious as to why the 650's are going to be more prone to knock than the 550s or 450s?

**asshanson** · 08-08-2008

Well you're converting the airflow signal to compensate for the bigger injectors right? So the engine thinks it has about 30% less airflow than it really does? Someone correct me if I'm wrong, but I believe that will mess up your timing so you'll be more prone to knock.

niterydr · 08-08-2008

Quote:

Originally Posted by slowboy

Well you're converting the airflow signal to compensate for the bigger injectors right? So the engine thinks it has about 30% less airflow than it really does? Someone correct me if I'm wrong, but I believe that will mess up your timing so you'll be more prone to knock.

Correct,

The reduced airflow % will lead to a lower "engine load" demand in the ecu's timing tables.

So instead of grabbing the top load row of timing values, say 11 degrees, the ecu thinks it is at 65% load and grabs 20 degrees, which will lead to detonation.

That is why it is crutial that your airflow % correction match your fuel needs as close as possible, should be +/- 15% at WOT, idealy.