well, after i installed my shorties, i noticed a slight ticking sound, after a day or two, it just went away, i just figured it as pistoin slap (its done it from the factory) well, yesterday, i retuned my truck, i took out the rest of torque manegement, and installed a tune copied from a radix kit. just the timing part anyways, anyhow, my truck runs alot better! i got that hesitation completely rid of, and i beat that harley davidson last night. however, when i rapped my engine up under boost, at 5000 rpm, i got a loud rattling sound. (detonation?) ive never heard a sound like this before. ive heard detonation before, but does it sound different when its under 6lb of boost? it sound like someone spilt a bad of rice. anyways, i noticed that after that run, the tick was back. and it didnt go away like it usually does. so i made another run, i heard the rice sound again, and the tick got slightly louder. so ive stopped what im doing, and tring to locate the tick. i noticed its alot louder under the truck than above the truck. it does not get louder when i hit the gas, but it does tick faster, i checked my header bolts and they are not loose. i have not checked the collectors, or the spark plugs. but i was just curious if anyone had any suggestions. i hate to say it, but i sounded like it was coming from the back of the motor twards the tranny. but its hard to tell.. if i turn my ear this way, it sound like its from over there, and so on. i cut an aluminum arrow so that i just had a 2 foot pipe, and tried to listen but i didnt find it. I realize that that radix tune is for an intercooled engine, and since im not intercooled yet, there might be too much timeing. but my truck sure runs faster now.

 

that sound of rice to me seemed like something was rattling around real fast

 

Pull the spark plugs and see what you find. Do you have a scan tool? If so .. take it out and check for KR.

 

i got a scan tool, but it requires a laptop, so i was using my buddies. and he just sold it! sob

 

That rice sound is audible knock. You need to do a log and pull some timing where the knock comes in. if you get 4* of knock take out 2* of timing where it occurs, if it is still there take another degree out. Maybe the ticking you are hearing is a bad lifter, possibly a valve. One thing is for sure , its not a bearing (they don't tick when they go).

 

I agree with work in progress. That "bag of rice" sound is detonation. I am almost certain you are running too much timing. Before I was intecooled I tried to run six degrees more timing --detonation like mad :sad: I would reduce your timing 2* in the HO spark table from coordinate (0.32,1600rpms) to the lower right corner of the table. If you still get that sound, reduce two more. Check your O2readings with this new tune to make sure are getting enough fuel too. You should be around .90-.92

FYI bigguy: you will love the intercooler. I upped the boost 4.5lbs and increased the timing six degrees, on the same octane pump gas!!! I have the fuel to match too with 42lb injectors. I get no detonation

 

i get that detonation only at 5,000 rpms and higher if im at full throttle? do i still need to reduce timing all the way from 1600?

 

You are right, you don't have to do it that low in the rpms. I guess that was just covering my bases when I gave you that information. And, it is easier than doing it perfectly since we are just trying to figure out what is going on exactly.

If you know exactly when it is knocking, you can plot where you are on the HO spark table by calculating your grams per cylinder. You will have to log this stuff though to get it perfect using your MAF's grams/sec readouts. Convert those g/s to grams/cyl and look at what rpm you are running in also. There you go...a dead pinpoint of where you are in the HO spark table. If you now know this, you can just reduce timing in that little sector instead of reducing most of the table.

The above is not accounting for the timing variances due to the Fuel Ratio vs. RPM Modifier table though. If you zero that modifier table out, you will be exact 100% of the time with your ignition inputs and what you will see when you log.

If you cannot log, then I would just take it from cell (0.32,3600rpm) just to be safe.

 

well... i reduced my timein by 3 degrees in the problem area,,,and its alot better now.. but i still get some ping. so ill go 2 more degrees and see how that works.... now i noticed something else,, my truck seems to be missing somewhat at idle... almost like i got a cam or something. the truck kinda vibrates slightly. im scared stiff, and i got to pull a trailer to work tomorrow!

 

Did you check those plugs out? You may have cooked one with the detonation.

I'd get a new set just to be safe .. it's not but about 12 bucks.