No more Detonation! *MIAC*
 

I have had a problem with Detonation or MIAC (Marbles In A Can - sound). I went to mid-grade or prem gas and the problem went away. The other day I tried a very simple way to stop coolant from going threw the Throttle Body so now the air going in the engine is much cooler and now I can run reg-87oct again without detonation! I was surprised this simple one min-fix worked so well! I did what "dsmdriver" suggested on this page he's #52. It also felt like more power too!

https://www.rx8club.com/series-i-do-yourself-forum-73/diy-throttle-body-bypass-mod-36389/page3/

Why do you think the owners manual recomends using Premium?

So you did the coolant bypass on the throttle body and now you can run regular?
I need to disconnect that anyway. I can not run regular down here in this heat., or even middle grade. I get detonation anyway, and I am using Premium. Shell or Chevron.
I think my AF is igniting as it's passing through the intake.

When I bought it they showed me were Prem was recommended but said reg was fine. I used it for the first 20K, then it started to get MIAC and I switched to mid and prem and it was fine. First of my seven rotary cars that I have had to run prem in and I did when its needed. The heated up Throttle Body is not needed in my area and robs me. It was 109F here today and no detonation and more power when the Throttle body is not heat soaked. I was very surprised it was so easy to fix...droped in a "sheet rock screw" . Took a minute, now my Throttle body is cool and does not heat up the air going into the engine.

I'm sure hot coolant running through mine is no good either. I'm getting a new engine in about a week so, I'll wait till then but I'm going to do this mod.
I also find it possible to run mid grade in the winter time here. When it gets below 80. lol.

If heat is your problem, invest in good coolant or a radiator upgrade.

Why if a penny screw and a minute of your time fixes it.....I'm simply disabling a feature I don't need that is heating up the air as it goes in the engine. We all know how much inter coolers help, this is the opposite and fine for the colder climates not needed for the hotter ones.

did anyone make a video on this?

Old Rotor could you post picture of where you put this screw? thanks.

Here is some pics of one way to do it, its a bypass. I just stopped the coolant from passing through. I found this pic so you can see, look at the sixth pic down and remove the hose as they show and drop in a sheet rock screw where the hose goes on the throttle body and push the hose back on and then slide the clamp back into place again. Of-course do this on a cold engine so you don't get burned. It seals both directions as the screw head was large enough to do the trick.


http://rotaryinsider.com/rx8-59.html

Thank you, it was as easy as pie.:lol2:

It recommends, it does not say it is required.

( Many cars run engine coolant through the throttle body in order to warm it up so the throttle body doesn't get filled with ice due to a mix of cold temps, humidity, and condensation. This is done because car manufacturers cannot design a car to work for "most" people, they are expected to make cars that work in any condition.)

Same goes for type of gas,,,,,,,,,,,

Now it feels a little stronger and will be even better on the cooler days. I could not run reg-87 in the summer before I did this.

The TB Mod is good. Beforehand you can't touch it after running for 5 min. in 80 degree heat. You will burn yourself. After the mod it's hot but you can touch it.

This easy fix is great. You can feel the difference, and all it took was a screw and one minute.

Rather than insert a screw I went ahead and did a bypass. I'll know in about a week if this mod cures the detonation problem I have using 87octane. Anyway, If it does not cure the problem it will be easy enough to return back to stock.

would this DIY help fix the problem I'm having where my cars RPM rises and falls and my car shakes a lot, but when I turn the A/C off it's just fine. It still shakes a little but no where near as hard. wtf is up with the car? Dealership told me they couldn't find anything wrong.

Think this might help me out? :Wconfused

^ no, it wouldn't.

This mod generally doesn't do much in the way of anything you'll notice.

It is normal for the RPM to fluctuate a bit when the A/C cycles.
The shaking problem could be a worn motor mount

I had the same summer detonation on 87 gas. Did the screw mod and it's gone.
What happens? It cannot be due to the air temperature - the air flow seems too fast to pickup so much heat to make a difference. Are we really this close to the limit? Or we are tricking the ECU to think the engine is "cold" and to use a different fuel map and indirectly prevent detonation. In the other thread someone seemed to get slight improvements in gas milage - this would support the different fuel map suspicion.

On the plus side - if we get detonation, we might have really high compression, so the dreaded engine change TSB seem to be far away ;o)

I went for a ride up North the other day, and the throttle body wasn't even warm.
Great little fix.

Wonder at what air temp. should I take the screw out?

Under 60F you should not hear pinging on 87 any more... I'll take my screw out once temps get close to 50F max for the day. Of course, if you removed the screw too soon, the pinging (or whatever that noise really is) on 87 gas will be back (for me at 5000RPM in second gear only)...

Whats it say on the gas door?

My Dealer told me the same thing. Said it was norm for cars to do this when the A/C is on. Even out here (Las Vegas) where it gets real hot.

This mod helped me.
Before this mod my RPM's would drop and my car would shake like it was going to stall when I was useing the A/C and my car would over heat. After doing this mod I can feel more pull and no more drop/shake RPM's when useing the A/C.
I went to In N' Out parked in the shade with the A/C on. I could hear my fans run on and off like norm. But my cars idle was smooth and not shaking and my car did not over heat.
-Gil

Bumped due to a question. Does this cause a rougher idle?

^none. only cools intake air.