just got off the dyno, need advice

[viper92086]

ok guys i just got back from the dyno today i think i did pretty good minus the problem i need help with.

mods:
na-t
turbo electronics
hardpipes
maf-t
stock 440's
3" exhuast
spearco IC
psi on the dyno chart is as follows: 13psi, 13psi, 11.7psi, 10.6psi (turned off boost controller)

dyno was a dynapack, so from what the owner said it reads about 9% less than other dynos, but its far more accurate

problem:
altho the car ran great you can hear i am getting detenation at above 5500rpm which is def not good. the tuner was saying its not the worse hes heard but its def not good and was suggesting higher octane (i used 93 octane which is the highest i can get besides race fuel), or maybe my valve springs are going or maybe even not enough fuel. this is why i'm going to ask you guys for your opinion. Now i have my maf-t (basic) setup so that my a/f is roughly 11.8. my timing is set to factory (10 i beleive)

solution?
what should i do? how do i tackle this? i was thinking should i put more fuel into WOT using the maf-t? do i need bigger injectors? etc. i'm not too good when it comes to fully understanding detenation, but hopefully you guys can educate me :1zhelp:.


edit: btw i should also say i was detonating at stock psi also at the same rpm

 

[92TealSupra]

You said your air to fuel is 11.8 so that is already running pretty rich, i wouldn't think you would want to add more, but higher octane would reduce knock of course, your timing is 10 degree's before TDC, That shouldn't be affecting your knock right now, plenty of guys keep stock timing and still do not run into those problems. If you want those you can turn your car on and mess with the timing and see if you can hear a difference while adjusting the cps.

 

[suprahero]

I didn't know that 11.8 was too rich at wot.......I thought anything at 11.2-11.8 would be pretty good. Do you tune your car to 12.0?

Nice torque curve Viper.

 

[92TealSupra]

That torque curve is pretty steep, that is very nice to have and you have a ct-26.

 

[viper92086]

You said your air to fuel is 11.8 so that is already running pretty rich, i wouldn't think you would want to add more, but higher octane would reduce knock of course, your timing is 10 degree's before TDC, That shouldn't be affecting your knock right now, plenty of guys keep stock timing and still do not run into those problems. If you want those you can turn your car on and mess with the timing and see if you can hear a difference while adjusting the cps.

hmm, dont forget this is na-t, i cant remember if people said to retard it more. i cant hear the detonation unless its on the dyno.

I didn't know that 11.8 was too rich at wot.......I thought anything at 11.2-11.8 would be pretty good. Do you tune your car to 12.0?

Nice torque curve Viper.

my car is tuned to 11.8, i thought that it was optimal... but the tuner is saying more fuel reduces detonation.

That torque curve is pretty steep, that is very nice to have and you have a ct-26.

thanks yup stock rebuilt ct

 

[grimreaper]

what are your plugs at? what brand and gap....

 

[92TealSupra]

hmm, dont forget this is na-t, i cant remember if people said to retard it more. i cant hear the detonation unless its on the dyno.



my car is tuned to 11.8, i thought that it was optimal... but the tuner is saying more fuel reduces detonation.



thanks yup stock rebuilt ct

Octane is a anti-knock agent that is added to gasoline, the tuner said more fuel will get rid of knock but I was almost positive it's the octane, maybe though mass amounts of fuel can do the same I will research that, that is news to my ears.

 

[viper92086]

what are your plugs at? what brand and gap....

autolite platinums, they are gapped to tsrm spec, i think it was .35 or something i cant remember off the top of my head

Octane is a anti-knock agent that is added to gasoline, the tuner said more fuel will get rid of knock but I was almost positive it's the octane, maybe though mass amounts of fuel can do the same I will research that, that is news to my ears.

thats what i thought too... lol but i figure the tuner knows whats up, i'm learning about this still :1zhelp:

 

[viper92086]

ok i just pulled the spark plugs and they are white, so that means the cylinder temps are too hot. i assume this may be leading to my problem? should i try to find 1 step colder plugs?

 

[SC61 MK3]

autolite 3923 gapped to down to 30

walmart carries them

 

[Clueless]

ok i just pulled the spark plugs and they are white, so that means the cylinder temps are too hot. i assume this may be leading to my problem? should i try to find 1 step colder plugs?

white plugs means too hot and/or lack of fuel...how faraway is your wideband sensor from the turbo and how old is it??

 

[foreverpsycotic]

Also look into pulling a bit of timing, and make sure that everythingis timed correctly (cams, cps, crank pully)

 

[viper92086]

white plugs means too hot and/or lack of fuel...how faraway is your wideband sensor from the turbo and how old is it??

wideband was located near the end of the downpipe before the cat

Also look into pulling a bit of timing, and make sure that everythingis timed correctly (cams, cps, crank pully)

i will check it out again

 

[hottscennessey]

A lot of bad information in this thread

11.8 is a great AFR on pump gas, I'd keep it at that.

Keep your timing at factory spec. Don't mess with it because it will only cause problems. The base timing needs to stay synced with the ECU so the ECU knows where it is. There are better ways to control timing/detonation.

When you say you "heard detonation" what do you mean? What did it sound like?

As far as plugs go, I'd recommend NGK BKR7E's, I didn't have good luck with autolites on my setup. The NGK's are just as cheap, if not cheaper.

 

[viper92086]

A lot of bad information in this thread

11.8 is a great AFR on pump gas, I'd keep it at that.

Keep your timing at factory spec. Don't mess with it because it will only cause problems. The base timing needs to stay synced with the ECU so the ECU knows where it is. There are better ways to control timing/detonation.

When you say you "heard detonation" what do you mean? What did it sound like?

As far as plugs go, I'd recommend NGK BKR7E's, I didn't have good luck with autolites on my setup. The NGK's are just as cheap, if not cheaper.

it sounded like nuts jiggling in the engine on high rpms (tuner said 5500rpm and up he can hear it). everyone that was with me said it sounded like detonation. its not something you can hear in cabin while driving. as far as plugs do you think that swapping them out for another brand will make a difference? these plugs are about 2 months old and i remember someone long ago saying that they were great

 

[IJ.]

Octane is a anti-knock agent that is added to gasoline, the tuner said more fuel will get rid of knock but I was almost positive it's the octane, maybe though mass amounts of fuel can do the same I will research that, that is news to my ears.

That there is just plain embarrasing......

I agree with Scott there's a bunch of garbage pretending to be information in this thread....

If you can HEAR it rattle on the Dyno it's going to be much worse in the real world under part throttle loads when you can't hear it due to road noise....

 

[viper92086]

what would you suggest IJ?

i'm going to check my maft settings tonight to see if they are off, and also is it just me or does my power come in really early.

 

[grimreaper]

does the ge ecu pull timing in the upper rpms like the gte?

 

[viper92086]

does the ge ecu pull timing in the upper rpms like the gte?

i have a GTE ecu, but iceberg may have an idea. we're going to mess around with some of my maf-t settings later tonight and we'll see how it turns out

 

[IJ.]

Viper: Sorry never worked with a MAFT anything so can't help.