does anyone know why I'm getting detonation (only from what i've experienced) @ WOT in 4th gear in my 05 evo 8? Anyone know how to correct it? Its just a load bang and jolt through the car. Cant be good for the engine. Thanks in advance.

 

A loud bang and jerk isn't detonation.

What exactly is the car doing? Mods?

 

it feels like its accelerating then just slows a split second if that, load bang and jerk (feels like detonation honestly), then takes off like it brand new. K&N air intake is the only mod.

 

ur timing off? or r u hitting fuel cut?

 

loud bang? Hmm Ususaly not detonation but I wouldn't completely rule it out.

How many miles do you have. This one is gonna be tough to figure out.

You will need some tools and knowledge of the innerworkings of your car. But i am gonna have you check if you need a tune up first. Just to rule that out and make sure no-body makes dumb mistakes.

You know you maintaince records so determine the last time you did a tune up and if its due again, you can't diagnose a car that isn't properly maintained.

Next up, check knocking or detonation occurs when the combustion chamber temperature becomes hot enough to ignite the combustion charge before the spark is fired. Usually doesn't cause the symptoms you are experiencing. Knocking causes a pinging like sound, or a ticking. When I over boosted due to boost controller failure in my evo I remember the shaking more than anything else, but the exhaust note was off to. The ping might be hard to hear. But no Loud bangs.
Things that can cause knocking are as follows:
1st is -highly advanced ignition timing (in this case the spark firing too early is cause the knock not the combustion chamber temperature.)
2nd the octane rating of the gasoline being too low (the highter the octane points the hotter the combustion charge has to become before it explodes) What can cause it to lower, well oil can. If oil gets into the combustion chamber and mixes with the combustion charge it will be like you are using lower octane rated fuel.
3rd too much boost pressure, The more boost pressure the hotter the intake charge is, the hotter the intake charge the hotter the combustion charge, Add some compression and it gets hotter then bang.
The list can go on but those are the common causes.

Start with checking your upper IC pipe for large amounts of oil if you really think its detonation. Don't condemn your turbocharger if you find oil, there can be other causes.

But Personally I have to agree with everyone else here that its not premature detonation or knock (which every you prefer to call it).

It sounds like a rich-fire, or exhaust explosion that is causing a vibration at the right frequency 6-8kHz to reach the knock sensor which in turn alerts the ECU of the "detected knock" which in turn retards ignition timing. Then Since the "detected knock" is no longer present the ignition timing is advanced again and you car goes fast. NOT A BACK-FIRE!!!! no a back fire is a literally what is sounds like a explosion that goes back into the intake manifold. Please do not confuse it with a Rich-Fire.

 

My first thought was fuel cut.

 

If its untuned, then perhaps fuel cut.

Or simply a misfire to old or ungapped plugs

 

Fuel cut. Do a search for the K&N intake. It plays hell with the MAF signal.

If it's just a drop in filter it still sounds like fuel cut. Needs to be tuned.

Just my $.02

 

if u have a DP and no tune u r prob over boosting or getting a fuel cut

 

I'm going to agree with others, you're probably hitting fuel cut, happened to me on my '05 before I got tuned....

The loud "bang" was the car rocking on the suspension... you know kinda like the "rear diff clunk" some people get when shifting....

Wait till its a little warmer and try it, if it does not do it when its warmer out, it probably is fuel cut. Also, the 4th gear thing makes sense as well for cut... highest load cell... mine was worse cause I had a full 3" exhaust as well, hit it in 3rd gear too, but only when it was really cold outside.

 

Fuel cut! I would check the wires/spark plugs too just to be sure but it sounds like fuel cut.

 

fuel cut can be defeated with a tune, but you need to log the car to find out exactly what's going on. check my website for links to the equipment you need and I have a video tutorial that explains how to use it.

 

I get what everybody is saying...Honestly, I have tons of experience with cars and engines in general but minimal experience with Turbocharged cars. The plugs and wires might be bad. I think I'll change those and then check on a tune. I really dont want to tune it until I get so more mods though. I've been testing it every so often and its pretty consistant. The problem happens at about 4000rpm i think, and if I could guess I would say it some kind of explosion. But not sure really, as I said previously. Car is completly stock other than custom UIC pipe, K&N drop-in filter and Turbotronics Godzilla BOV.

 

Could check your sparkplugs for carbon buildup. Replace plugs, gap, reinstall. How loud are these sounds you're describing? Could be misfiring or sparkblow out, but I still feel it is fuel cut. In some cars, feels like a brickwall. I'm just thinking of all the common problems with VIIIs.

 

Ohh you have a BOV?