Do you have severe afterfires at rev limiter?

greasemonkee · Post by **greasemonkee** » Sat Aug 09, 2008 7:16 pm

Seems odd, but then again, I may be odd. Mine afterfired so loud that one would mistaken it for a shotgun when I used the ignition cut. Then I switched to ignition and fuel cut and no change. Now I use fuel cut only and it doesn't seem quite as loud, but it still is terrible loud. I worry that this had contributed to my oil seal blowing out several months ago. If the fuel really cuts off, I have no clue what's happening.

Bindegal · Post by **Bindegal** » Sun Aug 10, 2008 3:24 am

Here, when using ign+fuelcut, sometimes (rarely)it is as if left-over fuel ignites in the exhaust after shifts. Which I figure is normal behaviour in this setup. So IÂ´m not complaining. Fuelcut only, no afterfires at all... but customers seem to like the ign+fuel cut, especially on NA engines. Makes a nice sound, that could be mistaken for a K20

/Allan

butch11a · Post by **butch11a** » Sun Aug 10, 2008 6:48 am

just experienced that today, i thought my engine blew up, now i know, have to change to just fuel cut only, is that how the oem ecu does it, just fuel cut?

Bindegal · Post by **Bindegal** » Sun Aug 10, 2008 7:03 am

butch11a wrote:just experienced that today, i thought my engine blew up, now i know, have to change to just fuel cut only, is that how the oem ecu does it, just fuel cut?

Yup, stock code does fuel-cut only. /Allan

JaredKaragen · Post by **JaredKaragen** » Sun Aug 10, 2008 10:38 pm

yep, the pops inbetween gears, and when letting off can also be from being pretty rich up top...

HiProfile · Post by **HiProfile** » Wed Sep 10, 2008 12:47 pm

You have to understand that with a motor, sometimes fuel can get 'stuck' around the rings, some will still be in the intake port, and some will be sprayed 1 rpm before burned. When you cut fuel, that residual gets burned in the following revolutions since you have spark. When you cut ignition, that raw fuel is mostly shot out into the exhaust - and makes a nice explosion when it hits a red-hot turbine housing or the next incomplete burn. With IGN+Fuel cut, you don't have any lean conditions, but you still get some fuel in the exhaust. Not as loud as an 'afterburn', but you get zero lean conditions. Boosted people don't like only fuel cut, since you could have a few combustions where you have high boost but a fraction of the fuel needed. That leads to small amounts of detonation here and there.

butch11a · Post by **butch11a** » Wed Sep 10, 2008 6:30 pm

I'm not sure about this but if you have an explosion in the exhaust system, won't the shockwave running through the pipe slow down turbine speed causing lag in between shifts? and won't it damage the turbo?

Post by **calvin** » Wed Sep 10, 2008 9:47 pm

i can fuck and blow a muffler;)

JaredKaragen · Post by **JaredKaragen** » Thu Sep 11, 2008 12:49 am

I have already posted a pic of a muffler that has exploded =D

Post by **Gaskleppie** » Thu Sep 11, 2008 2:14 am

i can f***

yes we know, you got a son now......

Post by **calvin** » Thu Sep 11, 2008 8:44 am

a big healthy boy

Orthello · Post by **Orthello** » Thu Sep 11, 2008 9:42 am

Gaskleppie wrote:
i can f***
yes we know, you got a son now......

What about the 'muffler' in this perspective

Like a pain in the ass?

crx303 · Post by **crx303** » Tue Sep 16, 2008 2:31 pm

Do you have severe afterfires at rev limiter?

Yes, and I like it

5thgen · Post by **5thgen** » Fri Oct 03, 2008 3:37 am

greasemonkee wrote:I worry that this had contributed to my oil seal blowing out several months ago.

I think I am in the same boat. My first turbo (sc34) started smoking pretty bad a couple months ago. I replaced it with a sc61 and it too is now letting oil past the turbine piston seal now. I am a little lost trying to find out why it is happening? I have pics of my drain line too if anyone wants to see them. Anyone else have a similar problem?

Post by **Bugermass** » Fri Oct 03, 2008 7:06 pm

using antilag for too long periods of time, oil contamination, too much oil pressure ( may need a restrictor) not letting it cool down long enough after boosting on it.. Blowoff valve too tight or not opening causing compressor surge. Those are a few things that can cause early turbo failure..

eCtune

Do you have severe afterfires at rev limiter?

Do you have severe afterfires at rev limiter?

Re: Do you have severe afterfires at rev limiter?