detination possably??????????? HELP please.

[shelbyplaya]

OK. SOOOOOOOOOOOO, I'm having some issues with what sounds like detination but when i pull my plugs they look perfect.

My motor is a hybrid 2.5l with wiseco pistons and a 2.0l top end. I'm running +40's/3 bar map on an 89 turbo 2.5l g-head/57 trim turbo cal. fuel pressure is set to 62psi with the vac connected. This happends in the top end of the power band weather it be at 5psi, 10psi or 15psi. My EGT's dont go above 1450/1500 at any given point. On the last compression test the car tested 170psi in all 4 cyls.

I have a pretty big event coming up and it a little un-neirving to hear this sound.... anyone got any ideas?

[overlordsshadow]

Maybe too rich up top? Makes a sputtering slowing down type sound?

[cordes]

What is your O2 reading?

[contraption22]

That G head cal may have too aggressive of a timing curve for your new combination. Have you plugged in the scanner to read the knock volts?

[turbovanman²]

How do you know, can you hear it?

Whats your base timing set at?

If this is my cal, I had 20 deg's initial with no detonation with 94 octane pump gas.

[shelbyplaya]

Maybe too rich up top? Makes a sputtering slowing down type sound?

Nope. Just a tingling type of sound


What is your O2 reading?

When I had it on the dyno it was almost 12:1 @ 15psi


That G head cal may have too aggressive of a timing curve for your new combination. Have you plugged in the scanner to read the knock volts?
No scanner. Dont know anyone with one.


How do you know, can you hear it?

Whats your base timing set at?

If this is my cal, I had 20 deg's initial with no detonation with 94 octane pump gas.


I can hear a tinging kinda sound
base timing is set to 6*. I've moved it as high as 14* and the tinging dosent get any worse.

I'm running 94 pump gas. I'll be running race fuel when i got to port alberni.


any idas? Should i add more fuel? Cant really retard the timing any more :S


I cant see why the timing would be to aggressive for a 16v with the cal coming off a 2.5l g-headded car(van). My 57 T3/T4 w/ .63 stage 2 turbine might be going on this weekend. Maybe remove a stock T3 w/ .63 stage 1 would help. flow ALOT more exhaust and air...

[Russ Jerome]

I can hear a tinging kinda sound
base timing is set to 6*. I've moved it as high as 14* and the tinging dosent get any worse.

I'm running 94 pump gas. I'll be running race fuel when i got to port alberni.


any idas? Should i add more fuel? Cant really retard the timing any more :S




Have you confirmed TDC on #1 with a dial indicator or a simple rod to see
if your *6 is realy 6*? Do this with 6 cars and 3 will be ahead and the
others behind on actual timing, have only seen a few of our cars that
were spot on stock timing marks. The bottom end of our 8v cals kept
me at 6* or less of base timing (explains why I was slow down low).

If the cal has knock enable were is the sensor mounted? I tried a lot
of places for the knock sensor from the intake to the lower block and
the only one that worked was those tapped holes in the head below
the exhaust manifold. All the others were deaf to knock.

Most of our cals are based off the S-60 stuff, more than one of my
cals wanted the goofy pinout grounded (30?) or it would be flat
down low regardless of base timing. Like I said the timing just seemed
to sharp down low for 8v cals but not enough when the 16head was
breathing up top.

Another thing I noticed in my setups (your results may vary) is if I
tried race fuel after driving my car and tuning all week is I would run
a lot slower on my pump gas tune up than my race gas tries. I could
run more timing but my best street tire runs of 12.0-12.3 were on
pump gas but my slower 12.5-12.7 runs were race fuel if I used
the same 6* base and 8v cal on the 16v head...thats what always
botherd me about never trying a cal actualy set up for a 16v head....
weird issues like that that make no sense on paper. I would retard
the timing even more as a test,just to listen to the motor and see
if you lose any more bottom or not.

[turbovanman²]

Interesting. I know that the cal Shelgame made me really woke up my TIII engine, :clap:

[Aries_Turbo]

russ, how did the sensor hold up to heat in that location. you would think that it would be too hot there.

Brian

[Russ Jerome]

Its a piezo elec sender, have to be pretty hot to irretate the internals.

Im curious now, I'll ask the present owner to look at it, its got thousands
of city and freeway miles on it.....of coarse they were all soft driven
miles rarely exceeding 140mph for more than 10 miles and never past
120 in the quarter :o

[shelbyplaya]

So i should make sure my timing is *correct* first.

I've got bottum end to spair. 310wtq @ 3000rpm ;)


Thanks. I'll give it a try. working on a new chip for the cal now.

[Aries_Turbo]

Its a piezo elec sender, have to be pretty hot to irretate the internals.

Im curious now, I'll ask the present owner to look at it, its got thousands
of city and freeway miles on it.....of coarse they were all soft driven
miles rarely exceeding 140mph for more than 10 miles and never past
120 in the quarter :o

hehe. driven easy i guess. ;)

im gathering parts for a hybrid and i need to choose a spot where the sensor gets good voltage from all cyls. i might see if someone can make a code mod that allows a separate timing table for each cyl. add timing for each cyl individually and see which location gives the best and most even knock sensor voltage. you can datalog the knock voltage with a scanner or with LMlog or SMEClog by jeff c. 10% higher than the noise threshold of the sensor when you dont have knock is actual knock. when running insane boost/power, your knock sensor voltage threshold table should be adjusted as the higher power will "ring" the block more and create false knock. it would be nice to have a low and high boost knock threshold table or a scaling factor based on boost.

Brian