I was in a long trip last weekend and I did the 70MPH boost test done by others (Ken?). Basically I hit the gas to get boost up (10-11psi) and I hear this sound which is like little rocks hitting the windshield. It is very low and you have to listen carefully to hear it. Is that detonation?? I have a 6# pulley with REM Diablo chip. Just curious. I can only hear that under those circumstances. Opinions welcome. Thanks.

 

Be very CAREFULL.

The fact that you think its is detonation is enough to warrant no more wot passes.

Detonation care sound like you described, get your truck on a dyno or have a local lightning or HD owner who knows the sound take the truck for a spin.

If you only hear it during wot then it prob is detonation.

Common during the cooler months, truck adds timing due to cooler air and cooler air is more dense =lean.

Driving normal is fine just becareful. No more hole in the block threads plz.

 

Definetly sounds like our arch enemy Dr Detonation!
Once again he rears his ugly head!

 

what you are hearing is probably "labor knock" and yes, it is detonation more than likely.

You need to add some octane boost or something similar. I haven't done this before, so I don't know what to tell you in terms of products...

The added octane will eliminate the noise if it is actually detonation.

So, you hit the throttle to get boost up, but no downshift... so you could hear the pinging... did it happen for just an instant and then go away or was it constant -- i.e. you kept getting the noise as long as you were in the throttle?

or, find the closest place that sells 104 and get at least a 50/50 mix of that plus 93 and see if it goes away. That stuff is $5 a gallon...

Last but not the least for sure: stay out of boost until corrected!

Ken

 

Without downshifting it stays a while but kindoff goes away as revs goes up. It doesn't happen (or I can't hear it) on WOT from stand still. Only in the 70mph run. What do you mean by 50/50 mix? Like 12 gallons of 104 and 12 gallons of 93 fuel?
I'm planning on getting the truck to REM and check it in their dyno. I'm VERY paranoid with those stories of flying rods (May 02 build here). Truck is grounded until I can get that checked

 

I was thinking more like hopefully you have a few gallons left and put a few gallons of 104 to bring the octane up.

Toluene will raise the octane as well.

This is just for testing purposes to see if it is detonation. It if is, the higher octane should elimiante or reduce it significantly.

If you kept hearing it while staying on the throttle, STOP DOING IT NOW. That's not good at all if it is detonation...

When mine did it and others I have talked to, it was "tip in". In other works, just a few little pings for maybe a 1/3-1/2 second and then went away.

Get it looked at before you get on it again...

Ken

 

I'll do. Thanks Ken

 

Did put 2 bottles of 104 to 1/4 tank and up to now the tickling is more audible I'm planning visiting REM friday for a Dyno run and checkup. Will see...

 

More audible?

Maybe you have a loose plug... beware the dreaded blown sparkplug...

Ken

 

man I sure hope you get that truck to a dyno and check the a/f ratio. It would be cheap insurance

 

HD 4mula :

what is your total list of mods?

Ken

 

Ken; I have REM 6# pulley, Diablo chip, the airbox mod + K&N and Boost bypass. I talked to REM and they said to take it easy until they check. I'm heading there tomorrow morning to check that and a dyno pull. May also put a FTVB if time permits. Will keep you posted.

 

Any updates?