TMO Datalogger, what to look for

[abakja1]

I read the VFAQ and did some searches, but have a question as Ive looked at some of my Datalogs,..

I have a 90 GSX with stock turbo, 95 pistons, port polished head, MBC set at 15-17 (depending on weather), 2 1/2 exhaust no cat, Dejon 2 1/2 uic, kn, aircan mods, rewired stock fuel pump,..I live in Hawaii where temp is pretty much 80 deg year round (lately high 80's though)

I got questions about timing advance and knock sum.

After looking my datalog, it seems I am in the .92v range when gunning it heading towards 80-85% throttle, but the timing advance went to 1-2 degrees (but at 12 noon on a 90 deg day) with a knock sum of 41-42, and between 17ms or so of injector pulse width on stock injectors going from 3500-4500 rpms..It stated at the VFAQ that anything below 15deg advance at WOT is bad. Also, how much knock sum is bad?

I want to know if Im getting enough fuel for my mods, but if my O2 sensor is around .92-.90V at WOT but Timing Advance is too low and knock sum is too high, do I turn the boost down or what? What else should I look at as well? I run 92 pump gas.

Also, I had a cold intake mod where I ran a laundry dryer vent hose from under the car to my exposed KN with aluminum shield,..But it was taken off by A friend who changed my clutch and said that cold air wont help anyways cause that incoming air will get heated up at the turbo and will run back to the intercooler,..But shouldnt it matter cause the TMO (and ECU) reads the intake air temp and thus effect timing?? Ive read that the intake air temp could be like 120deg stock, but with cold air mod like at 70 deg or something like that (cooler anyways),..

any help appreciated,..
abakja1

 

[-=TWITCH=-]

TURN THE FUKING BOOST DOWN!!!!!!!! if you are getting 1-2 deg timing and 40+ knock count you are killing your engine! Please turn the boost down. You want to tune for NO knock that means 0 not 40+ and over 18deg timing. Turn the boost way down and make a few runs. If everything looks good then slowly, turn the boost up a little log!

But please turn the boost down!

Chris

 

[-=TWITCH=-]

TURN THE FUKING BOOST DOWN!!!!!!!! if you are getting 1-2 deg timing and 40+ knock count you are killing your engine! Please turn the boost down. You want to tune for NO knock that means 0 not 40+ and over 18deg timing. Turn the boost way down and make a few runs. If everything looks good then slowly, turn the boost up a little log! You should only tune at 100% throttle floor it and watch the logger!

But please turn the boost down!

Chris

 

[abakja1]

Hmm,..too bad I cant run more boost,..Seems like I need to go back to factory boost settings (at 11psi or something) and with all the mods Ive done too,...Seems like all the mods for nothing,.....

How many psi can the stock fuel pump handle on a 90 GSX,...If stock is 36-38psi, up to how much can stock pump be adjusted to? 40 psi?

If I added a Walborl (sp?) fuel pump and adj fuel regulator to turn up the pressure can I get rid of the knock?
thanks
abakja1

 

[CarTunr22]

First off the "cold air mod" won't hurt you. It will probably help you a little bit but if ur runnng 40 knock u have a much bigger problem than your CAI can help. You need to turn down the boost like -=TWITCH=- said and carefully turn it up until u get a little bit above 0 from what i have heard it's ok if ur getting 7 for knock but beyond that is just danger. Try getting 550 injectors and a SAFC. what ever u do just take it slow

 

[Bohrn]

put the cold air thing back in, and turn the boost down to 15 psi.

Get the highest octane gas you can get regularly.

Get a bigger fuel pump.

Check for boost leaks, bad connections etc

Clean out your intercooler. This can be a big factor.

Now I betcha you are getting much lower knock and much better timing.

You might be able to turn up your boost now to 16 or even 17 again.

Mild MAF work would not hurt here either.

 

[abakja1]

How can I paste my datalog here to show you what my car is running,..
I did a couple more runs and still get too knock and low timing advance from 13-15-17psi,..

I put the cold air hose back on and air temp at filter is stable to 80-100 (down from 120-140),..got less knock,..but car still retarding advance to as low as 2 deg at 85% + throttle,...and knock went as high as 32 (down from the 40's though without cold air hose attached,..)

So I turned boost down to 10-11psi and get only 9 knock sum at most and around 12 deg timing advance at the least at 85-90% throttle,...Guess I need a fuel pump?

What is the most boost have people have run their stock fuel pumps on a 1g ( i got a 90 GSX) here at 80ish deg outside temp and with 95 pistons? Maybe cause of the 95 higher compress pistons is why I cant seem to run higher than stock boost pressures??

Plus, would I need a fuel pressure reg if I get a Walbro 255ph fp, or is my stock regulator good enough, and at what pressure should I see at idle with this??

any help please?
thanks much
abakja1

 

[-=TWITCH=-]

Originally posted by Bohrn
put the cold air thing back in, and turn the boost down to 15 psi.

Get the highest octane gas you can get regularly.

Get a bigger fuel pump.

Check for boost leaks, bad connections etc

Clean out your intercooler. This can be a big factor.

Now I betcha you are getting much lower knock and much better timing.

You might be able to turn up your boost now to 16 or even 17 again.

Mild MAF work would not hurt here either.

Seems to me that you might need a new fuel pump! your stock fuel pump might be having problems. Turn the boost down even more and see if you can get your knock lower and your timing higher. I would get a 190 so you dont have to mess with the AFPR setup, because you will need one with the 255fp. And also try the above.

-=TWITCH=-

 

[Bohrn]

Even tho alot of people say that you need an aftermarket regulator with a 255, its not true. really.

I have a rewired 255 and it was fine. I never had the safc for several months after getting the big pump. All was/is well. I was even lean on the logger on all trims. I did some research before doing it, as I had heard this too, but when I asked people who do this for a living, they all assured me that it was a good idea to get the bigger pump and not to worry about overrunning the pressure reg. And they were right.

As for your situation, I'd say even your stock pump is probably not enough, it might be going south.

OR, you might want to change your fuel filter, and get your injectors flushed. that and do the other stuff I said.

You didn't clean out the intercooler yet did ya

 

[ahains]

You didn't mention it, but you are running the highest octane, right?

Step 1)Check your base timing.

You are getting what seems to me to be too much knock at stock boost levels, but I don't know how much of an effect the higher compression 2g pistons have. Maybe that is all it is. Checking your timing is easy and has a huge effect on knock. Plus it's usually not set correctly

Check your spark plugs - do they look like you're running lean? Maybe your fuel pump is fine. I would want to get more data before throwing money at the problem.

 

[abakja1]

Highest octane I can get is 92,..Can get the 76 gas station's 100 octane, but at $5 a gallon,..NO THANKS,...Actually, when I put in the 2 1/2 Dejon uicp on my GSX, I did clean out the intercooler,..not venting the hose from valve cover keeps thing clean in my intake too,..There was a little oil in there, but sure I got it all out,..As for the base timing, its at 11-12 deg at idle,..Guess I gotta make adjustments cause it should be at 8deg right?

As for the Walbro,..Ive heard that the 190 is about the same at lower rpms, but way better at the upper rpms where you need it, But if Im gonna change it should go 255 right?..Guess with a car that 13 yrs old, should change the fp,..What fuel pressure should the 255 be set at at idle? Or is this included in the instructions when I get it? I think Ill check the VFAQs on this to check out,..Anyone got leads on good prices on a 190? 255? Saw the Walbro 255 for sale on ebay for $90,..

any more suggestions??
thanks
abakja1

 

[Bohrn]

good to hear about the intercooler

run 92 always, and if you get a bigger pump, go with a 255, just not the HP version. You don't need to change the regulator if you don't want to or have the money for it.

and get that base timing set to 5deg. It won't show that on the logger, mine shows 7 at idle when warm, but some show 8. 11 tho, that is high, if your car has an extra 4 or 5 degrees timing it will knock easier.

Have you done the MCCC thing?? That can remove lots of carbon off your piston tops and intake valves. That can lead to higher compression and also it can cause hot spots, corners of chunks of carbon will glow red and if this ignites the fuel before the spark plug does the 2 flame fronts will collide. Knock.

 

[ahains]

Maybe you already know this, but you need to jumper a connector to ground when setting the base timing.
I put up a picture here:
http://hainspics.home.comcast.net/talon/basetimingjumper.jpg

This shows you the correct connector, and the other connector near there that is the wrong one.
I saw the wrong one first and almost started a fire, so I thought I should put up a picture so others didn't make the same mistake

Just jumper that one to ground..

HTH,
Adrian