[DOHCVTEC]

Got a fresh set of Hoosier R7s, Hawk Pads, everything working great, super excited to get to the track on Sunday
So I get to the track and this happens!

All 5 sessions I had the following problem:
After 1 lap or so, I would loose about half my boost and lots of power! I mean I could hardly pass miatas in the straights... It was extremely disappointing to say the least!!

Here is what and we have on the car:
Engine mods...
Roto Fab intake
Mamo Ported T/B
Exhaust...
everything else stock around the engine

All other mods are suspension, tires, brakes, aero...

Here is the data we collected using the toque app and conditions:
IATs stayed about 104 F
No check engine light, no codes, no misfires
Running shitty Arizona 91 octane + Torco
Ambient temps were between 80 - 90 F
Coolant and oil temps were all inline


Here is something interesting we noticed...
The throttle position values would drop to about 50% (down from like 87%) when this started to happen..
It would consistently happen after about 1 lap or a little over 1 minute...

that is where they stayed unless I did a full cool down lap.. after cool down I would get my power back and throttle reading would go back to normal for about half a minute then it would go away again...



No idea what this is, I highly doubt without any codes the Chevy can diag it correctly...
I am thinking maybe the Mamo T/B due to the odd throttle position reading causing a bottle neck and the drop in boost and power

Has anyone ever experienced this?
Thanks in advance!

[SFV1LE]

That's strange, you are in PTM Sport 2 or Race right?

I would not recommend Torco, I'd go straight 91 or add 101 unleaded from pumps at track--5 gallons per full tank is enough to get up to 93+, I always do that at track in CA, running mostly 91 octane also.

This seems like something worth getting a dyno test with logging, etc. to answer the question quickly--it's serious. But don't let them touch the tune if you care about warranty :-)

[JonDaddy82]

Air in the supercharger system might be something to look at.

[juice3]

Does the track you go to not have 100 octane on the pump?

[gtfoxy]

In for answers.

[3.8TransAM]

Originally Posted by JonDaddy82

Air in the supercharger system might be something to look at.

I was going to say the same thing, especially with it happening after it gets hot and going away on cool downs.

[PROMETHEUS]

I would guess you either have air in the SC lines or the TB is working correctly. Put the OEM TB back on the car and take it out somewhere you can do some spirited driving and see if it replicates the problem. My bet is the SC is cavitating from air in the lines.

[DOHCVTEC]

So air in the supercharger cooling system was brought up to me also by someone else but the interesting thing is we took a look at the intake air temperature and it wes steady at about 104° even when I was losing power.. so I don't know if it rules that out or not. Also the exhaust tips had an unusual amount of discoloration looking like the car was running really rich
But most importantly while this was happening we were showing throttle at 50% even though I was down to the floor

[DOHCVTEC]

Car is at the dealership right now, checking everything out it'll probably be there for a couple of days but I highly doubt they will figure out what this problem is. I have my old throttle body and I will install it as soon as I get the car back see if there's any way I can recreate the scenario but it requires very spirited driving

[gtfoxy]

Isn’t there an AIT1 & AIT2?

Edumacate me.

What else would cause this?

[DOHCVTEC]

I do not know which one. Whatever is available on the toque app.. what's the difference between the two?

[jvandy50]

I’m guessing your rain tray was out? Only reason i ask is because i forgot mine til a couple sessions in last track day lol. Car didn’t have any issues, but I’m sure it didn’t help much either.

I have the same mods on my car and if i weren’t planning on tuning, I’d take them off and go back to stock.

[Gunkk]

Check for air in the Supercharger coolant loop. If the coolant pump cavitates it will shut off for 3 minutes.

Originally Posted by DOHCVTEC

So air in the supercharger cooling system was brought up to me also by someone else but the interesting thing is we took a look at the intake air temperature and it wes steady at about 104° even when I was losing power.. so I don't know if it rules that out or not. Also the exhaust tips had an unusual amount of discoloration looking like the car was running really rich
But most importantly while this was happening we were showing throttle at 50% even though I was down to the floor

The closed throttle plate and also the bypass valve may prevent you from seeing higher IATs in this scenario. Our cars are pretty smart and will indeed protect themselves from us blowing them up... so the ECU might have just put you into "low-power-mode" aka "sorta-limp-mode" and limited throttle and boost. Full-rich is another way the ECU can prevent the engine from blowing up. It all kinda lines up in my mind. But what do I know.

[Juiced1]

All cars have a cat protection mode that shoots extra fuel at the motor when it's running hot. So it will run very rich to cool the cats down.



The cars will pull throttle when they sense and issue. You were abusing the car and I'm guessing the temps were bad. You said 104 degrees on the intake temps which is not going to happen in 80-90 degree Arizona weather. That is your intake sensor before the blower. Manifold temps is what you need to log which I'm guessing was closer to 200 degrees.



Your car pulls timing when the manifold temps reach around 130 degrees. From there the power levels dip more and more the higher the temps get which freaks out the virtual torque tables........which can pull throttle.



Air in your supercharger coolant can cause your manifold intake temps to sky rocket. Especially when the pump shuts down (nightmare scenario)



Best thing is to buy a reservoir so you can fill it easily and check levels at the track.