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Old 01-18-2021, 04:30 PM   #1
ben_7
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Default Getting some knock readings on newly modified 2020 STi, what is the best way to avoid

Hi everyone,

I just did the first line of modifications to my 2020 STI which include:

- COBB Accessport
- COBB SF Intake + Airbox
- COBB three port EBCS
- IAG Street Series AOS
- nameless midpipe to complete my nameless cat back exhaust system (I only had the nameless axleback before)
- killer b oil pickup and baffle kit

My STi is pro-tuned for 91 octane gas and the boost has been raised from 16.2 psi which I believe came stock for the 2019+ STiís to around 19 psi and it briefly overboosts to 20.6 psi, which is what my boost gauge currently shows.

My tuning shop tells me that the mustang dyno they use show underrated numbers, so my car dynoed at 275whp and 301 wtq.

A bit of a story as to why Iím concerned about heat soak prevention...

So my tuner asks me to data log for him after driving around a couple of days and after I did this, he noticed some knock on the higher end during some pulls which he made some adjustments for, and sent me a revised map to data log against.

On this map, during pulls I noticed my feedback knock values hit -2.8 sometimes and my fine knock learn hit anywhere between -3 and -5 on certain pulls but whenever I got into boost, it was steadily around -1.4 until I got off the throttle where it would then return to zero or if I was on low boost, it would stay on zero as well.

The dynamic advance multiplier value has always been at 1 thank God.

When I told this to my tuner, he said my intake temps were through the roof, sometimes hitting 140F and he told me to stop getting into boost whenever my intake temps were above 100F.

Since Iím new at a modifying STiís, I thought I just had to watch out for the coolant temps being at approximately 180F before getting on boost, however I will now watch my intake temps more closely.

So he told me to reset my ECU via the Accessport to get rid of the fine knock trims and start over by data logging again and hitting boost with intake temps under 100F.

The issue there is that I noticed my intake temps build up quite fast which means I should not be getting into boost, so here are my questions:

1. Should I buy a COBB turbo heat shield and/or turbo jacket?

2. Should I invest in a process west tmic? (Iím not interested in going fmic as Iím not upgrading my turbo or going for high horsepower levels. I only plan to put a downpipe, up pipe, koyo rad, and fuel system upgrade minus flex fuel hopefully by the summer of this year for my next set of power modifications)

Even though E85 burns cooler, it will increase the power, thereby making my engine work harder and risk trouble without my engine being properly built to handle above 350whp and similar wtq levels.

With the second set of mods I listed, I hope to get around 310whp and 330-340wtq on a 91 dyno tune and thatís more than enough power for me on an STi.

I do plan to take my car to the track a few times a year when possible so Iíd like to do that safely which is why I wanted my tune to be set more for reliability than power.

Thanks and please let me know your suggestions.
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Last edited by ben_7; 01-18-2021 at 04:44 PM.
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Old 01-26-2021, 03:45 AM   #2
kharmicresonance
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Default

Well, I may be confused here, But you took a 2020 STi to a tuner, with those mods, paid $$$ for them to raise the boost and lower your HP/TQ? ( the 2020s were spec'ed at 310whp but a few have been dyno'ed straight off the showroom floor at 280whp on mustang dynos ) The Stage1 OTS Cobb Map itself is supposed to be good for something like 290whp/330tq.

And then they told you to just not drive in boost when the intake is over 100F? They did not even offer to look at your airbox to determine why it was not pulling cool air in from outside?

Remember, that heatsoak is usually only present after you have sat at a stop for a few minutes. And that the stock intercooler can overcome heatsoak in less than a minute ( although it will only ever get temps down to within 10-30 degrees of ambient depending on atmospheric conditions) If your tuner is leading to you believe that you are running into heatsoak *at speed* then you should question them on how they think that is happening. Because there are thousands of other 2020 STis running around without that problem putting out more power *stock*.

Save your car, and your money, and find a better tuner.
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Old 01-26-2021, 06:54 AM   #3
12wrx1
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What he said.....
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Old 01-26-2021, 08:12 AM   #4
horsePOOGAS
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When you're data logging, is it in stop and go traffic or rural road/highway cruising? If you're logging in stop and go traffic and then doing WOT pulls (say entering on a highway or whatever) I could understand why your intake temps are high at the time of the pull.

Whenever I've done data logging and WOT pulls for my tuner I have a specific route I always take. Long straights, few stop signs, and plenty of room to do a WOT pull after I've been driving for a bit. All that is to make sure my intercooler and coolant temps are at the lowest possible for the pulls.

But along with what Kharmicresonance said - Your tuner should be asking you the right questions to figure out why.
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Old 01-27-2021, 11:45 AM   #5
subaru_gc8
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if your dam is staying high, don't worry about it, you are just being paranoid.
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Old 01-27-2021, 11:54 AM   #6
JP Chestnut
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I'd get a new tuner. "Don't get on boost when your intake temps are about 100" isn't a solution. You paid money and killed your warranty -- I'd be hoping for a little more than what you're getting.
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Old 01-29-2021, 08:18 AM   #7
hotdog
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As others have said: You've done insanely little to your car, and your tuner sounds like a goober. Go find better. You've voided your warranty and he's having you do a labor of driving around and logging? **** that. Find someone better.
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Old 01-29-2021, 08:56 AM   #8
Unabomber
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1. Should I buy a COBB turbo heat shield and/or turbo jacket? Heat protection is never a bad idea. The best/cheapest avenue for this is https://forums.nasioc.com/forums/sho....php?t=2298336. Will this solve your issue? No. But it should help.

2. Should I invest in a process west tmic? (I'm not interested in going fmic as I'm not upgrading my turbo or going for high horsepower levels. I only plan to put a downpipe, up pipe, koyo rad, and fuel system upgrade minus flex fuel hopefully by the summer of this year for my next set of power modifications). No. No intercooler on earth will help with intake temperatures as those are read PREintercooler.

I'd also recommend you watch some Cobb videos and website documentation on what the AccessPORT reads and when/when not to be concerned. I think you are pissing yourself for no good reason. I keep my AccessPORT in the drawer below my computer. It stays in the off position save for an update twice a year for fun. It monitors the room's temperature just fine.

Your intake temp is a concern. Causes:

1. Your intake may not be installed correctly.
2. You are idling the car and/or are in heavy traffic for awhile before you do your pulls.
3. Your temp sensor is fubar.

Prior to doing a log pull you should be cruising around like a Christian and allowing your car to come up to temp nicely and you should see that your normal cruising intake temp is 10ish degrees above air temp at speed. So its 90 outside, your intake temp...at a nice 40mph...should be like 100. Each car is a bit different of course, so go with YOUR normal.
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Old 01-29-2021, 12:39 PM   #9
DrD
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Quote:
Originally Posted by ben_7 View Post
When I told this to my tuner, he said my intake temps were through the roof, sometimes hitting 140F and he told me to stop getting into boost whenever my intake temps were above 100F.
That's like basically saying "don't hit boost in the summer"! Were the temps that high while just sitting there idling, or while driving around?
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