Summer heat... how bad does it affect your ride?

[Calan]

The first 10-15 minutes that I drive my car in the afternoon heat (95-100*), it runs pretty good... after that I start getting knock. I'm running around 15-17 psi boost on pump (91 or 93.. doesn't make a lot of difference, although my chip is set for 91). At night and early mornings, it runs strong for the most part, but still knocks a bit after a couple of pulls (heat soak?).

I've tried running richer, leaner, with meth/water, just water, etc. I've also moved my air filter out of the engine bay completely and to a front fresh air intake, and wrapped my IC pipes (except for the j-pipe and lower).

I was thinking it was just IAT temps, but with the IC output pipes wrapped and the air coming from outside the bay, I dunno. The TB elbow still feels hot though, although it could be from heat transfer during the time I'm getting out of the car and popping the hood. Even if it is still IAT temps, shouldn't I be able to dial it out with water injection?

On another semi-related note, last night I hacked the stock radiator ducting so it would fit with my FMIC, and put it back in. The car is now actually running a bit hotter if anything. I've got a lower air damn sending a bit of air up into the radiator which helps by maybe 5*. I'm also running a 20-80 mix with water wetter and dual fans, but the temps skyrocket to around 230 anytime I turn the a/c on. With it off, they are around 206-213.

It's frustrating... anyone else having to deal with this?

 

[DBordersX]

What octane are you running? I'd think that with all that stuff, especially water/meth injection, you would be able to control knock. I know the summer heat affects engines though.

I ride a scooter to work to save gas/insurance/mileage. In the morning when it's cool (70*) I top out at about 35mph on flat ground, on the way home (95-105*) I can only get 30mph out of it . Maybe the answer is to move to a cooler more consistent climate, i.e. Hawaii

 

[Calan]

What octane are you running? I'd think that with all that stuff, especially water/meth injection, you would be able to control knock.

I'm running 93 right now; 91 was completely hopeless last time I tried it... I got knock at only 13-15 psi boost, no matter what I try. It's at least managable with 93.

As for the water/meth injection...I haven't seen much (if any) advantage to it. I've actually heard this from a couple of knowledgable people, but everyone around here seems to really support it, so I thought I would give it a shot. Maybe it's only my setup, but I just don't see it making much difference. I've tried every mix combination, different nozzle sizes, different AFR settings... I dunno.

Hopefully it will cool down soon. We have a cold front moving in this weekend and highs should "only" be in the mid/high 90's.

 

[turbodsm18]

I'm running 93 right now; 91 was completely hopeless last time I tried it... I got knock at only 13-15 psi boost, no matter what I try. It's at least managable with 93.

As for the water/meth injection...I haven't seen much (if any) advantage to it. I've actually heard this from a couple of knowledgable people, but everyone around here seems to really support it, so I thought I would give it a shot. Maybe it's only my setup, but I just don't see it making much difference. I've tried every mix combination, different nozzle sizes, different AFR settings... I dunno.

Hopefully it will cool down soon. We have a cold front moving in this weekend and highs should "only" be in the mid/high 90's.

If you are getting knock at 13-15 psi on 91 octane on a 16g, seems like you may have other problems.

After as you car being a dog in the heat, after the coolant temps hit *206, I believe the ECU pulls 1* timing. It also does something when you AIT get to a certain temp.

 

[Calan]

yeah... IAT is ignored though (Maf-T and custom chip).

If there is something else going on, I'm at a loss. I've been all over this thing in the last 3 months with all new ... well almost everything that can be bolted on

 

[Calan]

I think it has to do with what the MAF-T is doing with the timing. I need to find a good resource that describes exactly what happens with air, fuel, and timing with each setting on the MAF-T and have a look at it. The MAF-T site/manual doesn't say a lot about specifics.

 

[turbodsm18]

I will be honest, I have never worked with the Maf-T but it just doesnt seem right to knock on 13-15 psi on a 16g.

When you had the chip burned, did you specify what octane fuel you were gonna run.

 

[Calan]

yeah... Jeff even burned me a new chip fo the 91 (excellent customer service I must say).

I've thought of a couple other possibilities:

1. My AFPR isn't doing what it should be...but I need a fuel pressure gauge to check this while driving.

2. My AFR reading could be off, but I don't think it would be by much. I'm using MMcD, with the WB connected to the EGRT input. From what little I checked, it seems to correspond pretty closely with the Zeitronix logging software... but I'm not sure at the extremes (9-10 or so). Regardless of this, even if I tune rich/lean just to try and eliminate the knock, it's a hit and miss effort... usually miss

There has to be a fine balance between air, fuel, timing, and water/meth injection that I'm just not hitting... or if I get it, then the temps sore and it's off again... or my FMIC heatsoaks and it's off again... or... blah blah blah

 

[turbodsm18]

yeah... Jeff even burned me a new chip fo the 91 (excellent customer service I must say).

I've thought of a couple other possibilities:

1. My AFPR isn't doing what it should be...but I need a fuel pressure gauge to check this while driving.

2. My AFR reading could be off, but I don't think it would be by much. I'm using MMcD, with the WB connected to the EGRT input. From what little I checked, it seems to correspond pretty closely with the Zeitronix logging software... but I'm not sure at the extremes (9-10 or so). Regardless of this, even if I tune rich/lean just to try and eliminate the knock, it's a hit and miss effort... usually miss

There has to be a fine balance between air, fuel, timing, and water/meth injection that I'm just not hitting... or if I get it, then the temps sore and it's off again... or my FMIC heatsoaks and it's off again... or... blah blah blah

Just hook a gauge up to the AFPR and make sure the pressure changes with revs.

Also, have you checked your car for boost leaks?

 

[Calan]

Boost leak tests are good... holds 20psi with a slow bleed.. takes about 45 secs to fall to 10psi and then slows down some more.

I have an under-hood gauge on the AFPR. It holds steady at factory pressure at idle, but I have no way to see what it's doing as I build boost. Also need to see if it's holding pressure after shutting the car off just for giggles... (there seems to be some debate about this between Aeromotive and the wisemen around here .

 

[turbodsm18]

You dont need to see if it rises with boost, just make sure as you rev the car at idle it goes up. Also, I think after mine sits for a day or so, I lose my fuel pressure

 

[Calan]

How do you know if you are getting a true 1:1 rise in fuel pressure to boost pressure, if you aren't monitoring it against actual boost?

Not being a smart-A$$, just wondering what you're getting at...

 

[turbodsm18]

you trust the FPR.

I have an aeromotive and I have never had a problem with it

 

[linksys42]

How do you know if you are getting a true 1:1 rise in fuel pressure to boost pressure, if you aren't monitoring it against actual boost?

Not being a smart-A$$, just wondering what you're getting at...

You could also get an in cabin electronic fuel pressure gage with the sending unit. Just install the sending unit into the afpr, and then you know that it’s rising at 1:1. I was a little worried about the electronic not being accurate so I have both the mech gage and the elec fuel pressure sending unit taped into my AFPR.

 

[Calan]

You could also get an in cabin electronic fuel pressure gage with the sending unit.

Yeah... that's the plan... wanna throw those big bucks my way for one of those?

 

[DJ23GSX]

you trust the FPR.

I have an aeromotive and I have never had a problem with it

I have an aeromotive and had to send it back because the the diaphram ripped. It was causing all kinds of knock issues under boost because it wasn't rising 1:1. At first the 4 bolts on my afpr that squeeze/seal the diapham between the top and the bottom backed themselves out a bit causing knock. Once i tightened them knock was gone until the diaphram ripped. Once the diaphram rips you'll have fuel coming out of the vacuum port and the car will run/idle like shit but at idle the fp gauge was still reading the right fp its just under boost where everything gets wacky.

Have you teflan taped all the threads on your afpr yet? Its helped alot more people than you would imagine. If your vaccum port is leaking under boost then your not going to rise 1:1. Just a thought.

Good luck

 

[Calan]

Well it was a bit cooler this afternoon, and the car was running really good. Actually it ran for about 30 mins while cruising around on errands without a single count of knock. Then out of the blue... 7 counts... and then a few minutes later about 18... both on a couple of 2nd/3rd gear stoplight romps maybe 15 minutes apart.

Then it calmed back down and is around 2-5 at WOT now.

Freakin gremlins

 

[romeen]

How do you know if you are getting a true 1:1 rise in fuel pressure to boost pressure, if you aren't monitoring it against actual boost?

Craig, I have never actually tried this but it seems like it might work. Use FP check connector to activate FP and get fuel pressure in the system. Then pressurize your intake (boost leak test) and check to see if the fuel pressure rises appropriately. If I am missing something obvious and this won't work let me know. My old brain isn't as sharp as it used to be.

 

[Calan]

hmmm.. wonder if the pump will run long enough to do that?

Might be worth a try though... as long as I remember to disable the water injection. Don't want puddles in the intake triggered by the test pressure

 

[romeen]

as long as I remember to disable the water injection. Don't want puddles in the intake triggered by the test pressure

Yes, very good point! As long as the ignition is NOT turned to ACC it shouldn't activate the system. But better safe than sorry.

If you do end up trying it let me know if it works.

 

[Calan]

Something else I thought of....

Lately I've noticed that my AFR reading will occasionally just freeze, usually at 15.1 (simulated NB is at 100%), for a few minutes.. then it will just automagically start working again. It's done it maybe 3 times in the last week.

I'm wondering if it could be "glitching" when I don't see it, causing momentary confusion for the ECU? I would think this would only affect closed loop and the ability to set trims, but who knows.

 

[DJ23GSX]

I was having ecu issues a few months ago with random knock issues that i couldn't tune out but as soon as i replaced the ecu with a freshly rebuilt one i was able to tune out the knock.

How's your base timing? Are your timing marks lined up perfectly?

With your mod list i can't see why you'd be knocking.

 

[Calan]

ECU is a new rebuild from Keydiver. All timing components are new and correctly timed. Base timing is solid at 5*, runs between 7-10 at idle on logger.

 

[linksys42]

Yeah... that's the plan... wanna throw those big bucks my way for one of those?

Here ya go http://www.prosportgauges.com/amber.php
Look at the very bottom $44.50 I have the exact same one and its accurate in comparison to the mech FP gage on my AFPR. They are just not made out of the best materials and the lenses scratch easy. But does the trick! And only cost $45 for the gage and sending unit. Hope this helps.

If you think the knock is a result in FP dropping off log/monitor the battery voltage to see what it's doing after driving for a while? Do you have your lower and upper heat shields installed on your o2 hosing and exhaust manifold. It could be the heat from the turbo affecting the efficiency of the alternator not being able to keep up. And affecting the voltage/amperage that the fuel pump is seeing.

 

[nightspeed87]

Yea you need to confirm your fuel system is adequate. How old is your fuel pump?
But realistically if you have a wideband and it doesnt show the engine leaning out then it has to be raising at a 1:1 ratio... If it doesnt lean out then id say the knock is due to heat soak or something else...Are there any excessive rattles or vibrations under your hood that may trigger a phantom knock like ocurrance? Because on my car my 3in dp is touching the transfer case due to the angle of the evo3 o2housing and when i rev it up to stuttarbox, if i rev it too fast the harsh vibrations of dp and tc contact cause me to hit a bunch of phantom knock during the rev up, but if i rev it up to its set 5500 launch rpm real slow it wont register any knock.
And also what compression pistons are you running and what type of timing maps... This could tell me a lot...