Over-run Change ! Help !!
 

I recently removed my intercooler cleaned it and refitted, also during this time i wrapped my down-pipe and fitted a perrin turbo jacket.

The first run out the small rubber hose which tees off and goes to my boost gauge in car blew off, i refitted the hose and secured it properly.

Ever since this happened the popping and banging on overrun has stopped, now i don't know if this was the hose coming off or the work with intercooler etc.

I have checked all over for boost leak/vac leak and cannot figure out what has happened,

The car drives great if anything feels better i would say,

I have attached two snaps from my datalogs

The only diff i can see is the column i have called boost which was manifold pressure it appears i have more of a vaccuum now without the pops and bangs.

Could it be that i have previously had a slight leak somewhere at intercooler and sealed it ?

I have also noticed my oil temps don't rise anywhere near as quick and peak about 5 degrees lower.

Any help or advise would be appreciated :thumb:

I would have thought the oil temps coming down was a good thing, :Whatever_

Seems like you've ur vehicle has remapped itself and sorted its timing out:D as the pops and bangs are created with retarding your timing basically when your over 2500rpm rest your foot on the accelerator and the timing gets retarded then you have pops and bangs, the intercooler should have no effect and if there was a boost leAk or a vac pipe split it would defo not drive better but worse

Maybe your car has just leRnt to correct itself so no pops and bangs for you till you get them mapped in :D

ALS FTW :D

You can see the timing has been retarded tho.

Give that intercooler and pipes one more check over and take your time you'll find something loose/split or not on properly like the intercooler to turbo elbow pipe or the inlet to intercooler or the vac/boost pipes I'm in no way saying your incompetent but we are only human and can make mistakes hope you sort it let us know how you get on:thumb:

Its a frount mount.

Also if there was a boost like or vac leak surely the vaccuum in my manifold wpuld go down.

It boosts and drives great.
It also dnt explain why oil temps dropped.

U can see by my logs i have more of a vaccuum now without the pops so that points at no leak no ?

Might seem silly question but how much fuel is in the tank as mine won't pop and bang if it's well below quarter and also won't do it if the cars not up to temp aswell like a safety measure if you will

Plenty of fuel in it, its really bugging me,

Like i says if anything when i compare both the logs i have posted i see more of a vacuum on the log where it doesn't pop,
You can see timing is still the same,

Even more strange is that if sat still it pops like crazy when i rev it,

But on the move i get nothing,

Again car drives great and reaches and holds boost fine too.


:confused::confused:

Anyone able to see anything on those logs that i can't ?

This has me stumped, no leaks anywhere, everything hooked up properly,

Car drives great like i says holds 1.7 bar and oil temps are lower.

Strange that it still pops like it used to when i am not moving, like sat still dip clutch and rev it i get loads of pops,

Yet off throttle and rolling when up the rev range there's nothing even tho it is mapped to do it ?

Your AFR`s in the 1st pic with pops look alot leaner than those of the no pops log.

altho my car is controlled by the closed loop settings i found the richer my AFR`s on over run the less pops i had, so i made my fuel table a bit leaner and this altered the corrections made within closed loop and i get more pops on over run with leaner AFR


Also the more retarded my timing was, the less pops i have, go figure.


altho it probably means a hotter exhaust temp but at low load im not too worried

Clutch in and rev it is launch control isn't it? Not over run I maybe wrong had that on my last bug

Has launch control too but thats not what i am saying.

Clutch in clutch out makes no diff.
Sat still when i rev it it pops same as always as revs drop.

Now when driving and i come off the throttle but stay in gear at higher revs i get nothing where as before i got the pops etc on the over run.

Go for a drive when revs are coming down just rest your foot on accelerator when and at over 2500 rpm you'll get them have a little play

You can get pops and bangs without resting your foot on the throttle by increasing the rpm on the overrun/reinjection,but makes for a horrible driving car imo as you lose engine braking.

Have you tried changing the wgdc in the area you have vacuum say from -11 to 0?

Your right bro but I find I can make music when tapping or resting on mine :D

I don't think you are getting me, I am not altering anything to do with the map i am only looking at the logs to see what has changed if anything ?

I had the pops etc. they were mapped in on purpose,
They would happen all the time off throttle above 2000rpm

I could also tap the pedal on overrun do make it happen on purpose,

This no longer happens,

and that is what i cant understand for it to be happening all the time and now suddenly stop,

"I recently removed my intercooler cleaned it and refitted, also during this time i wrapped my down-pipe and fitted a perrin turbo jacket.

The first run out the small rubber hose which tees off and goes to my boost gauge in car blew off, i refitted the hose and secured it properly.

Ever since this happened the popping and banging on overrun has stopped, now i don't know if this was the hose coming off or the work with intercooler etc.

I have checked all over for boost leak/vac leak and cannot figure out what has happened,

The car drives great if anything feels better i would say,

I have attached two snaps from my datalogs

The only diff i can see is the column i have called boost which was manifold pressure it appears i have more of a vaccuum now without the pops and bangs.

Could it be that i have previously had a slight leak somewhere at intercooler and sealed it ?

I have also noticed my oil temps don't rise anywhere near as quick and peak about 5 degrees lower"

I get what you're saying,I was suggesting changing the wgdc as you have changed the setup slightly by securing pipes etc after pops and bangs were mapped in.

I'm not saying the change in manifold vacuum would make a difference,was just a suggestion.

I have to move my finger onto the switch but then the party really does gets started :banana:

So it is possible that there was a slight leak before i removed intercooler which has gone un-noticed and now i have sealed it is why they are gone ?

I am only uessing now as on the logs the only real change is a tiny bit more vacuum.

You can also see on both logs that the WGDC is 0

C***t :p I not got LC :cry:

I'm sure an experienced mapper would spot a leak,I probably wouldn't be able to spot a small leak tbh but I'm far from an seasoned tuner lol.

Possible a small leak could cause slight overfueling so the mapper didn't have to add much fuel?
Log 1 looks pretty lean for pops and bangs.

Have a word with your mapper if you can,see what he suggests.

ALS is the daddy for over run fireworks :D

Sorry ALS bro had it on the bug crazy!

See i was hoping someone would be able to read the logs or advise on what else to check and log ?

It is the first one which had them, im guessing the second one is rich because the feul is still there but not burning off with a bang

There is a big difference with the AFR in log 1&2
So as The Rig suggested,a leaner AFR seems to produce the bangs,I always thought of it the other way,adding fuel and retard ignition.

If it was me I would try leaning out the top row where you're on the over run to see if this brings them back.

Disclaimer: I'm not suggesting you alter your map in any way,please seek professional advice :D

Surely its best to find out why they have suddenly stopped instead of just altering map to make it pop again,

For it to suddenly change something has happened.

I am not chasing the noise i want to know why it has disappeared,

Shouldn't just stop all of a sudden.

Log 1 @3k rpm 14:7afr(estimated) with 17:11 actual
Log 2 @3k rpm 14:7afr with 11:6 actual

Just need to find out why so rich compared to log 1

Sorry I couldn't help,will keep an eye on the thread,always good to learn new stuff and hope you get it sorted.

have you had a look at night from behind the car, is it possible your pops have turned into little flames instead? You have injector duty active and -20 negative timing on both log snips so you have the building blocks there for tickets to the gun show. If the vac level/amount of air in the manifold has changed (due you to you creating/fixing a leak) then the result would be a change in the amount of fuel introduced on overrun which would change the end result.

are you running a standard recirc dump valve or aftermarket jobby?
where is the boost gauge T'd off from?
what happens if the boost gauge "accidentally" falls off again? Is it possible there was a bit of a leak there before and it effected the operation of the dump/recirc valve?

Running an aftermarket dump valve bolted onto the intercooler piping just before the throttle body. Looks like a tial. Could be a copy.

The boost gauge was teed off of the line going to the dump valve.

Car runs fine

And the stranger thing is how much better my oil temps are.