5 Liter Eater

Above ~800 or so on pump and meth you're heavily dependent on the meth for octane and depending on your fuel system, perhaps fuel in general. I'm not confident that the meth is distributing evenly at that volume but that's just my theory. I've moved to corn and while I haven't been running it that long I feel better about it, but that just may be a warm fuzzy and it's moot for this topic anyhow.

The vast majority of motor problems seen here, myself included, are cracked and/or melted pistons or squashed and/or cracked ring lands or lifted and/or torched heads. All due to detonation. Mostly from guys pushing the bounds of pump and meth. You can't tell me its not risky or fool proof just due to the sheer number of failures I've seen. Most guys in this thread, myself included have seen these types failures and are recommending more like 15 degrees. Now I may be thinking about this from a ~900 RWHP pump and meth standpoint but IMHO 20+ degrees on pump and meth making over 700 @ 14# is considered overly aggressive to put it mildly.

winters97gt

What were you running on the Novi 1500 5 years making 730-760rwhp? Completely an apples to oranges comparison since that was a stock longblock with a baby cam, but curious.

MVP'S ZO6

As it's been stated, each combo is different and will like what it likes. In other words there are too many variables to simply say run X amount of timing. A good tuner will have a couple sets of plugs to swap and read them when doing WOT tuning as well as any other acquired data in order to ensure the most optimum performance from a given combo. Just because you can put x amount of timing in a combo and it don't trip the knock sensors and the plugs look good don't necessarily mean that's the right amount of timing.

How the car is driven also plays a role in things. A car that's mostly street driven with the occasional rolling blast down the highway Vs. a car that sees more track time than street time can play a role in timing required for best performance.

Speaking of things like spark plugs, it's always better to start with a plug that is too cold rather than one that's on the ragged edge or too hot. It is much easier and cheaper to replace a set of fouled plugs than it is to replace anything below your pushrods.


Inaddition to the aforementioned, if you're on a load bearing Dyno; it wouldn't make much sense to increase timing once you reach the Max Torque for any given Engine RPM and Load. Most of us play with fire. (quite literally) As the old saying goes, everything is fine until it's not.

5 Liter Eater

It was only like 730/675 with the stock LS2, Novi 1500, cam and headers. Not sure its the final tune I had on it before removing it but I found a tune from 2011 and it has 13-14 degrees in it.

JDS99

I ran like 27deg in my diesel on straight pump, no meth, and 20psi boost or so.. don't know what the big deal is

Detoxx03

Allan and the guys at Futral know what they are doing. Hell you've seen the Futral cars on the streets including mine run.

Robert 2000

My combo is very similar to yours. I am also running 20* of timing. My tuner said he saw no detonation during pulls and data logging and he was extra careful tuning my car it is on the richer side which I am happy with. I am on stock block, overspun si trim, 93 and meth with 9.5 or so compression. The car has seen many 2-3-4 pulls in the last 4 months or so.

I would think if 2 different reputable tuners with very similar setups are ending up close in timing advance that maybe thats what the setup likes.

BLOWNBLUEZ06@RKT Performance

What the motor likes isn't up to the tuner to decide. It's up to him to discover based on feedback from the vehicle, compiling various forms of data to come up with the recipe for that combo.

I've said it many times. The motor likes what it likes.


Bret

juice12

The motor likes what the motor liked until you get **** gas and have no room for error in the tune. I choose not to risk it anymore.

realcanuk

Dead on. I ran 20 degrees in my stock LS2 on 14 lbs of boost and never had an issue.

A quote from one of the most respected tuners out there.

"Give the engine what it wants and invent a theory as to why later"

CamminC5

My 9.5:1 390ci with a 2.85" pulley on a YSI likes 24* with meth. She never knocks.

The engine wants what it wants.

416yellowz

Thank you for all the input guys!!

SquatchMachining

I have had the same experience, I was just seeing minimal returns after 22 degrees so that is where I backed it down to.

BLOWNBLUEZ06@RKT Performance

That's not to say a good tuner finds max power/torque on the dyno, leaves it there and sends his customer down the road. That's not included in my definition of a good tuner.

If someone wants added protection, tune the car for safety on 87 pump and let it eat, but that's not going to save someone if the station accidentally puts ethanol in the regular tanks, meaning there are no guarantees in this game.

BLOWNBLUEZ06@RKT Performance

The losers talk about WHY they cant.

The winners talk about HOW they did.

ajrothm

Remember...On the dyno, and on the track/street are two different things...

We just went through this recently with my buddy's GS...ECS 1500 w/restrictor, NA cam, headers/x pipe, 93/meth, A6. A big name local shop built/tuned it. The tuner is known for being aggressive and known to make big numbers on the dyno... This one did not disappoint.. 701 rwhp on 9psi. Logged it, no knock and 19* of timing.... My buddy told him to back a couple degrees out of it for safety.

A month or two later, we have the car at the track, my buddy is setting up his HPT configs so he can start logging himself. First off, the car would barely get down the track due to incorrect shift programming... banging the limiter on 2 out of 3 shifts. car went a 10.50@139.

Lucky for us, another local tuner who is well known was at the track, he is very good on A6 tuning, he hopped in, loaded one of his TCM programs.. Instantly the car shifted perfect, car goes 9.79@141. Logging the car this time, we notice it had 5* of KR all through 3rd and 4th. We open his tune file and see the timing at 19*.... The first tuner never readjusted the tune at the request of the customer.

We pull the timing back to 16*, take the car out, next pass goes 9.56@143 with 0 KR. We didn't have fresh plugs to throw in and read after a pass so we left it where it was at.

This is a prime example of tune on the street/track and give it what it wants, not what the dyno says or the tuner says will work when he never pulled a plug..

4 second dyno pull is nothing compared to a 9-10 sec WOT blast.

Everyone has their own theories of how to tune, how to deceifer what the engine wants etc..... But if you aren't logging, aren't reading fresh plugs etc etc, and relying solely on dyno pulls for your tune, its just a matter of time until you melt something. Especially relying on your tuner to give you a "safe" tune yet you have no idea what he put in it.

Pekka_Perkeles

Very interesting.

Of course I don't know why your engine detonated.

But I'd still like to comment.

But back to the basics.

1. Make sure your tuner has proper equipment. If he/she doesn't use knock headphones, find another tuner. While checking plugs is fine and nothing wrong with that, every tuner should monitor the engine during dyno runs, not just afterwards.

2. Make sure your tuner asks you about every single part of your engine combination. As an example, a knock sensor being at different location than from the original may need adjustments in the tune (i.e. LS2/LS3 block in C5). Your engine may knock wildly without PCM ever noticing that. Again, with proper equipment, your tuner will notice knock way before checking plugs.

3. Make sure your tuner makes a proper load test for your car/engine. Not all engines need a full torture test, but if you're going to use your car in a standing mile, then simulate that in the dyno as well.

As for street racing, several, rather short subsequent WOT tests at dyno will show how efficient your IC or meth kit is and how knock-resistant your engine is. It also gives your tuner a feedback how well the other parts, such as heat range of the spark plugs in your engine, are taking the abuse.

4. Forget the $500 tunes for highly modified engines. It takes time and skill to tune these kind of LS engines to last more than couple of seconds (of quarter mile glory). Would you prefer to pay more for tune, than just refresh the engine every year?

5. Ignition advance is not the only thing that destroys the engine. Wrong parts, failed fuel pumps, too much heat, leaking vacuum hoses, blown fueses, etc. The list is endless. As you have experienced, even with 15 degrees of advance, some engines blow and some others do not.

6. Log everything.

7. Do not trust internet forums. But you already knew that. :-)

And hey, greetings to (another forum member) ruusperi - still blowing engines or so? :-)

Pekka_Perkeles

And that is nothing compared to a proper load test at dyno.

See my previous post.

Agree, but it's also how you use the dyno.

For some car owners maybe it's just the short WOT run and the video in Internet... :-)

neverstop

that's BS that shop didn't pull the timing like the customer asked. I wish more shops would get publicly bad reviews when they do $hit work or blow stuff up through laziness or negligence. If the customer asks for a conservative tune and gets 20* imo that is not giving them what they want. It's amazing how bad some "big names" in this industry are when you see how their customer cars (not just the shop car) are treated, while they are never afraid to rack up $500 "tunes" or charge $150 an hour for BS work.

I will say a tuner previously had something like 22* of timing on my 9.5:1 compression forged MTI motor with 14psi and D1SC, 91 pump gas and dual M15 methanol. It made 760whp on the dyno and seemed fine on the street but one real WOT 1/2 mile pull at the track and that motor was instantly garbage. I'd personally rather take a few degrees of timing out my own setups so I can beat on them without worrying about nuking a motor or ruining a trip to the track. I'm not trying to set world records, just have fun.

neverstop

fyi, Vengeance and I believe ECS also have both documented methanol flow distribution issues when running dual M15 tips. I believe ECS said there were like 200*+ differences between cylinders on a car they were tuning that had cylinder by cylinder EGT sensors on a ~1,000whp supercharged c6 setup. There was a thread in here somewhere too where they discussed but I don't see it now

My dirty math shows that 200* difference in EGTs is perhaps a full point of AFR difference between cylinders. which is huge. They said they now don't run dual methanol kits with bigger than M10 tips. After talking to them I stepped down my dual meth setup a bit. ECS has perhaps built more tuned supercharged C6 corvettes than anyone in the world and Vengeance held the 1/2 mile world record with an 1,800whp c6 so I'd say those guys know what they're talking about probably more than just about anyone else alive.