How much timing do tuned heads/cam LT1's normally run?

I just got my car dyno tuned yesterday, and it had a mail order tune from pcmforless in it. My tuner said it had 43 degrees of timing in it at WOT in tune upper RPM's :eek: . I wasn't getting any knock even though it was running around 13.5:1, but he kept lowering the timing and adding fuel until it was at 13:1 across the board, and the total timing was 38 degrees. It gained 30ft lbs of torque at 3000, and I average torque was up atleast 15 ft lbs across the board. Peak hp was up 6, and peak torque was up 10 ft lbs. I was just wondering if 38 degrees sounds likea good number since it had 43 in it from the mail order tune.

Hi,

43 degrees total timing sounds like detonation time
to me even if you can't hear it. Even with race gas,
deburred chambers and pistons, cool running motor,
ect. ect.:rolleyes:
38 total pretty good and safe way to run it. Play with the
advance curve under total to set it up.
Reading the plugs is the best way to get it rite.

IMHO:)

Later

Irocing

Hi,

43 degrees total timing sounds like detonation time
to me even if you can't hear it. Even with race gas,
deburred chambers and pistons, cool running motor,
ect. ect.:rolleyes:
38 total pretty good and safe way to run it. Play with the
advance curve under total to set it up.
Reading the plugs is the best way to get it rite.

IMHO:)

Later

Irocing

I don't think it was detonating with 43 degrees, it didn't shoot out puffs of black smoke, but the dyno doesn't load the car up like it is on the road so who knows.

Was the 43 degrees reported by Datamaster or is it what was it in the Spark table? The LT1 PCM tends to add 2 to 4 degrees above and beyond whats in the Spark Table. Datamaster reports accurate timing ( I verified it). I run 38 degrees total timing. Increasing timing didn't help, and going to 36, I saw a slight drop on the Dyno. You may try a tad more fuel like 12.6 to 12.8 AFR. My car seems to make best power in that range. But, you're certainly in range and splitting hairs.

Steve

Was the 43 degrees reported by Datamaster or is it what was it in the Spark table? The LT1 PCM tends to add 2 to 4 degrees above and beyond whats in the Spark Table. Datamaster reports accurate timing ( I verified it). I run 38 degrees total timing. Increasing timing didn't help, and going to 36, I saw a slight drop on the Dyno. You may try a tad more fuel like 12.6 to 12.8 AFR. My car seems to make best power in that range. But, you're certainly in range and splitting hairs.

Steve
He tuned it with LT1 edit, so the 43 degrees was in the spark tables.

If he had 43 in the tables, it was likely seeing about 46 degrees. Way too much IMO.

The LT1 PCM tends to add 2 to 4 degrees above and beyond whats in the Spark Table.

Steve

Anyone know why this is? I've noticed it too on 96 and 97 LT1s and figured there must be a table Tuner Cat doesn't give me access to.

The common theory is that the exta timing is hardcoded at the higher RPMs and there isn't really a table. No one has ever really found the timing adder in the hack however. They all seem to do it. I Just Tune with a Datamaster log and adjust TC tables down till I get what I want. It's no big deal and not worth loosing sleep over.


Steve

You may try a tad more fuel like 12.6 to 12.8 AFR. My car seems to make best power in that range.

Ditto.

im at 36 total at WOT

i know this tread is a little old but i just got my 355 done with a 503 cam and pp heads and with the mail in tune it runs with 43* of timing at wot and it just feels really weak. do you guys think that the best thing for me to do is get a dyno tune because i think my car was faster before the cam and heads. just let me know what you think

i know this tread is a little old but i just got my 355 done with a 503 cam and pp heads and with the mail in tune it runs with 43* of timing at wot and it just feels really weak. do you guys think that the best thing for me to do is get a dyno tune because i think my car was faster before the cam and heads. just let me know what you think

Absolutely.

i know this tread is a little old but i just got my 355 done with a 503 cam and pp heads and with the mail in tune it runs with 43* of timing at wot and it just feels really weak. do you guys think that the best thing for me to do is get a dyno tune because i think my car was faster before the cam and heads. just let me know what you think

43* of timing at WOT?! :eek: Is the car detonating at all? If you have a 94-95 and have the cable to install the program, I can give your program a look over and fix that damn WOT timing. May I ask who did the tune?

well pcmforless did the tune but the problem is that i have a 93 so there is no way to retune unless i send it back. The car is acting wierd if the weather is perfect if runs decent but other than that not real good and it also melted a spark plug so i dont know what to do

I have a 93 with bolt on's and cam only (similar to hotcam on a 109 lsa). My WOT timing is at 42 from 3200 to 6500 (verified with TuneProRT) and is also a pcmforless tune. I plan on changing the tune (afr in the 11's and knock retard in some areas) when I get time and after I replace the front hubs.

well why would pcmforless run so much timing in there tunes