[Vwdiesel] Rabbit droppings # 53 -- ( understanding the worth of HILLBILLY tuning )

[gary]

Absolutely correct regarding cetane vs. injection timing to make for
ignition lag.

There was another thread a time ago that someone suggested we buy the
chemical outright. EthylNitrateHexane or something like that. The only
supplier found only sold it in 55gal drums. Enough for many lifetimes
over and over.

I accidentally over-dosed my TDI with a half bottle of PS. The car just
didn't feel right. I retarded the timing with my VAG-COM by -2 degrees
and it ran great again. Ran the tank down and refilled. Ran like crap
again. Restored the timing and all was well.

I would think there would be a SAE paper of the subject of Cetane vs.
Timing out there somewhere.

There was a thread a while ago as well, that either the Kalifornia CARB
or EPA, I forget which, did a study that by raising the national cetane
level from 40 to 43 would reduce diesel cold diesel smoking in big rigs
from something like 8 minutes to 30 seconds. Therefore reducing
particulate emissions. 

-Gary



On Mon, 2004-03-22 at 12:49, H.Hagar wrote:
> Lets take a look back at the days of plenty and HIGH octane gasoline.
> 
> Engine makers usa    increased compression ratios like mad ---- to outsell
> the competition with more horsie power. What does that have to do with tuning ?
> Quite a lot.    To use lower octane fuel we used HILLBILLY tuning. We kept
> slowly retarding spark to a no-knock setting.
> 
> Likewise diesel ,  we have to keep advancing pump to correct for crappy low
> cetane fuel. To do that with a dial-gage you would have to get the numbers for
> 40 cetane fuel from BOSCH.  Even then I would not do it , except as an experiment.
> 
> One of the things we are compensating for is Ignition Lag.Even the brand new
> 1984 Rabbit would need a correction. So what to do ???  Under dieselfuel 101 .
> I suggested that we increase cetane number , using a cheap chemical.
> Using the following reasoning. No way to test cetane number of stuff from pump.
> So we say it is fourthy   then add chemical to get to 45 or 50.--- So what if pump
> stuff is 50 ? --no problemo you drive on 60 fuel. NO way will it be too high.
> Lets use the same chemical as is used by ESSO ExxonBobil. etc.
> 
> The higher the cetane the lower the lag.
> 
> May be continued.
> 
> Hagar.
> 
> PS:   Loren suggested we make a group purchase  .Great idea. Count me in.
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