TR-6 Causing detonation at same timing as stock ignition?

[marleyskater420]

So a buddy and I are working on tuning his car, and he has a TR-6 ignition with the new truck coil.

He was previously getting a little bit of knock on a Turbotweak 6.1 chip for 91 octane and alky injection, and he had the alky turned all the way up and the AFR was pig-rich at 10.8 AFR.

I was wondering if the TR-6 provides such a hotter spark that it can cause detonation if you use the same timing tables as you previously used with the stock ignition system and coilpack?

Has anyone experienced anything like this?

FWIW, we were able to lean the car out and make her faster without detonating, with safe AFRs of 11.4-11.6, but it got me thinking if the TR-6 was providing such a hot spark that we could potentially pull some timing from the table, perhaps a degree or two, and the overall strength of the spark would still be as strong as the stock ignition/coil with the timing not-retarded.

Just a thought. We haven't tried anything like that yet. Figured I would ask here first.

Thanks!

 

[No disintegrations]

I imagine a hotter more energetic spark will in effect advance the burn rate because of a larger spark kernel having more surface area to work against.. So with that tr6 equipped will want less advance as you have found.
A caveat, I thought the stock spark was pretty damned hot too as far as I know.
Give er what she likes. Don't worry about the number just the result.

 

[Turbo6inKY]

So a buddy and I are working on tuning his car, and he has a TR-6 ignition with the new truck coil.

He was previously getting a little bit of knock on a Turbotweak 6.1 chip for 91 octane and alky injection, and he had the alky turned all the way up and the AFR was pig-rich at 10.8 AFR.

If it's real knock and not coming from driveline noise like wheelspin or the exhaust hitting the frame somewhere, then back the boost down or take some timing out. You're past the limit.

I was wondering if the TR-6 provides such a hotter spark that it can cause detonation if you use the same timing tables as you previously used with the stock ignition system and coilpack?

"hotter" spark doesn't cause detonation. Detonation is caused by cylinder pressure and heat exceeding the octane capability of the fuel. If it knocked at a certain point on the stock coil, it'll knock in the same place with the TR6. What the TR6 buys you is reliability and the ability to run a slightly larger plug gap, plus cylinder pressure from extremely high boost levels won't snuff the spark out.

But it's not going to cause or prevent detonation. That's all about fuel quality, timing, and boost levels.

 

[marleyskater420]

If it's real knock and not coming from driveline noise like wheelspin or the exhaust hitting the frame somewhere, then back the boost down or take some timing out. You're past the limit.



"hotter" spark doesn't cause detonation. Detonation is caused by cylinder pressure and heat exceeding the octane capability of the fuel. If it knocked at a certain point on the stock coil, it'll knock in the same place with the TR6. What the TR6 buys you is reliability and the ability to run a slightly larger plug gap, plus cylinder pressure from extremely high boost levels won't snuff the spark out.

But it's not going to cause or prevent detonation. That's all about fuel quality, timing, and boost levels.

Wouldn't a faster burn rate, which is what I'm trying to allude to, and what NoDisintegrations was saying, cause the cylinder pressure to build quicker than an ignition system that did not create such a rapid burn rate?

I understand that the TR-6 itself doesn't cause detonation. I apologize for the confusion.

I am asking if the increased burn rate, which leads to cylinder pressures rising quicker than if ignited from a spark that was not as strong and/or did not provide as quick ignition of the air/fuel mixture, could that increased burn rate lead to requiring less ignition timing, as now you have a more efficient combustion process.

Pulling numbers outta my ass here, for examples sake, if it took 20degrees for a stock ignition to build maximum cylinder pressure in this engine, would the TR-6 requires only 17 degrees of timing to obtain the same cylinder pressure, since it burns more efficiently and with more energy? Again, the 20 and 17 degrees were just numbers for example's sake to illustrate my question..

I'm under the impression that cylinder pressure is cylinder pressure. Btu is btu. If you can burn fuel quicker to create the same cylinder pressure, wouldn't you require less timing?

I feel like something very obvious is missing from this train of thought....if maximum cylinder pressure can be reached sooner, then less timing can be utilized...but how can we measure if maximum pressure has been obtained? hmm...I'm not quite sure how to, without a trip to the dragstrip or to a dyno...

any input is seriously appreciated. I'm a bit stuck here.


Abstractly, I'm thinking an analogy along the lines of hemispherical heads compared with conventional smaller combustion chamber cylinder heads, and the required timing to reach max cylinder pressure for each cylinder head type (I am aware that we are not discussing cylinder heads here, and that combustion chamber design is a far more acute example and factor in cylinder pressure than a comparable ignition system...within reason, of course)

 

[pacecarta]

once ignited the hotter spark as you call it has no effect on the burn rate ..the fuel octane controls the rate so it cant change the peak cylinder pressure .. if you ignite earlier yes you need to back timing off thats what ignition timing is ..

 

[pacecarta]

as far as pig rich at 10.8... i run mid 10s AF and lower on alky but the final ratio varies with boost low boost i run leaner 30psi 10.4-10.3 but if your 10.8 is just 93 with boost at lets say 17 psi.. thats rich
with two nozzles of alky theres less 93 in the mix more meth so the af needs to be lower to be where the meth which has has a lower stoich ..10.8 is not too rich .. https://www.hotrod.com/articles/power-in-methanol-racing-alternative-fuel/

 

[Jerryl]

I read somewhere here;
Lean = Mean

 

[marleyskater420]

once ignited the hotter spark as you call it has no effect on the burn rate ..the fuel octane controls the rate so it cant change the peak cylinder pressure .. if you ignite earlier yes you need to back timing off thats what ignition timing is ..

Makes absolute sense. I was ignoring the octane rating is the control here.

I appreciate the insight. Thank you.

The 10.8 is 91+alky on what was 21-23psi on a 5858 with unopened heads/stock cam/unopened bottom end.

I leaned it to 11.4 and the owner said it really picked up on the low end and boost response. Having not gone for a ride in the car prior to making the tuning changes, I couldn't say for myself what difference there was. The turbo did have a very linear and quick response though. Good torque and spooled fast. He has a PTC 10" right now and I bet with a 9.5" NLU it would be an absolute beast.

 

[pacecarta]

the alky control dial has a greater affect at mid boost 15psi area than it does at 23 ..setting knob full at 8 vs say 5 increases the alky pressure 30psi or more at 15psi boost but at WOT 23psi the alky pressure at 8 vs 5 may not even change infact above 22psi there is very little change in alky pressure
get one of razors testers and youll get to see what i mean first hand .. i usually set alky at around 5 and look for pressure of 75psi at 15psi on tester

 

[No disintegrations]

I read somewhere here;
Lean = Mean

Mean to parts, better to have some safety, haha

 

[No disintegrations]

once ignited the hotter spark as you call it has no effect on the burn rate ..the fuel octane controls the rate so it cant change the peak cylinder pressure .. if you ignite earlier yes you need to back timing off thats what ignition timing is ..

I'm think of the spark "Corona" or kernel. If it's bigger with more surface area and more energetic I think it would cause a faster propagation of the flame front.

 

[marleyskater420]

the alky control dial has a greater affect at mid boost 15psi area than it does at 23 ..setting knob full at 8 vs say 5 increases the alky pressure 30psi or more at 15psi boost but at WOT 23psi the alky pressure at 8 vs 5 may not even change infact above 22psi there is very little change in alky pressure
get one of razors testers and youll get to see what i mean first hand .. i usually set alky at around 5 and look for pressure of 75psi at 15psi on tester

Don't his kits at full tilt push out about 250psi?

How are you only getting 75psi?

I'm not exactly following how the flow of alky is not increased, regardless of boost pressure, if you increase the dial? Am I reading what you're writing incorrectly? I'm interpreting what you wrote as saying there is no difference in the amount of alky put into the engine when the dial is at 5 or turned up to 8....which doesn't make sense to me, because when I had one of the first kits Julio ever made, there was a BIG difference between 5 and 10 (I believe the old kits went up to 10 and didn't stop at 8).

It's also been like...13 years...so I could be wrong about the numbers he used, but there definitely was a difference between 2/3 flow and 100% flow.

Or am I interpreting what you're saying incorrectly?

 

[earlbrown]

Sometimes you have to learn when not to trust your tools. It's possible that you're even richer than you think. Imagine you're dumping so much fuel (possibly causing rich knock) that raw fuel exits the port and the WB see it..... it would read pig rich, right?


What if it's so rich that all the oxygen doesn't get burned? Then it's going to have a false reading showing leaner than actual.

Also, as far as octane=burn rate, that's not true and it's not fixed. In your case, if you started with a crappy ignition system that was band-aided with too much advance, then replacing it with a working ignition system would require 'retarding' the curve. AKA putting it back right.

From what you're typed, it sounds like you took a wrong turn at Albuquerque, and went down the wrong rabbit hole.

I'd back off the boost, back off the alky, ease off on the timing, see the engine work right, THEN start chasing the tune.

If you find the engine still isn't happy when it's not being pushed hard, that will tell you to look at the mechanicals instead of the knobs and settings.

 

[SCOOBY DOO]

Don't spose you boys hit record and saved a PL file did ya'?

 

[marleyskater420]

Sometimes you have to learn when not to trust your tools. It's possible that you're even richer than you think. Imagine you're dumping so much fuel (possibly causing rich knock) that raw fuel exits the port and the WB see it..... it would read pig rich, right?


What if it's so rich that all the oxygen doesn't get burned? Then it's going to have a false reading showing leaner than actual.

Also, as far as octane=burn rate, that's not true and it's not fixed. In your case, if you started with a crappy ignition system that was band-aided with too much advance, then replacing it with a working ignition system would require 'retarding' the curve. AKA putting it back right.

From what you're typed, it sounds like you took a wrong turn at Albuquerque, and went down the wrong rabbit hole.

I'd back off the boost, back off the alky, ease off on the timing, see the engine work right, THEN start chasing the tune.

If you find the engine still isn't happy when it's not being pushed hard, that will tell you to look at the mechanicals instead of the knobs and settings.

Yes! THANK YOU FOR YOUR INPUT!!!

I know this may sound silly, even with all the potential issues that could be going on...but I am so glad to know that the ignition situation/question was understood by someone, even with my poor explanation...and that my thoughts were correct! If anything, I will take that as a small victory for myself.

We will back off everything and make some hits to get a proper baseline.

Just out of curiosity, what plug gap do you recommend for a completely stock block (unported heads, stock cam, CR, etc) with 91 octance + alky injection, stock headers, TR-6 ignition system, TT 6.1 chip, wideband, 3" downpipe, GN1 fmic, PTE 5858 turbo. He currently has it at .35" but I was thinking that may be too large? What are your thoughts?

Thank you for all the help!

 

[NY Twin Turbo]

Don't his kits at full tilt push out about 250psi?

How are you only getting 75psi?

I'm not exactly following how the flow of alky is not increased, regardless of boost pressure, if you increase the dial? Am I reading what you're writing incorrectly? I'm interpreting what you wrote as saying there is no difference in the amount of alky put into the engine when the dial is at 5 or turned up to 8....which doesn't make sense to me, because when I had one of the first kits Julio ever made, there was a BIG difference between 5 and 10 (I believe the old kits went up to 10 and didn't stop at 8).

It's also been like...13 years...so I could be wrong about the numbers he used, but there definitely was a difference between 2/3 flow and 100% flow.

Or am I interpreting what you're saying incorrectly?

Tyler,

I think what Paul is saying is that at 15 pounds of boost, he typically sees around 75 PSI of alky. And this seems correct to me as I also have a twin nozzle set-up and typically see about 85 lbs of alky @ 15 pounds of boost with my knob a little below 6.

But as you approach the top of the alky dial, the alky pressure does not increase as much per pound of boost as it did lower on the dial. Meaning, you are already close to the "most alky per pound of boost" limit when you pass the 7 on the knob.

This doesn't mean your limited to 75 or 80 or 100 PSI of alky. It only means that the changes are more subtle as you approach the top of the dial. Then once your boost hits the low-mid 20 PSI mark, your alky is all in no matter where the knob is.......as long as it's somewhere on the top of the dial.

As far as the maximum alky PSI output goes, this is not the issue. If the same dial position is used as a constant, small nozzles, big nozzles, double nozzles, big double nozzles, and small double nozzles will all change the pressure readings at the sensor. Example, a small single nozzle does not allow as much alky to flow as a large double nozzle at the same settings and pump speed. So, alky pressure will read much higher even though much less alky is being sprayed into the intake.

How's that Paul? Did I get that right?

 

[NY Twin Turbo]

Just out of curiosity, what plug gap do you recommend for a completely stock block (unported heads, stock cam, CR, etc) with 91 octance + alky injection, stock headers, TR-6 ignition system, TT 6.1 chip, wideband, 3" downpipe, GN1 fmic, PTE 5858 turbo. He currently has it at .35" but I was thinking that may be too large? What are your thoughts?

I started this Spring with a new TR-6 set-up and after asking for advise, gapped the new plugs at 35.

So far, so good. Every single parameter has been perfect. So, I haven't even pulled them to check yet. But I may do this weekend.

Maybe start there?

 

[michael evans]

In talking to Helo I took it that the pressure in the line is the same (when system is activated ) and the knob only controls the ramp up time to the full on.

He said in my case it should be 110 pounds.

 

[marleyskater420]

Tyler,

I think what Paul is saying is that at 15 pounds of boost, he typically sees around 75 PSI of alky. And this seems correct to me as I also have a twin nozzle set-up and typically see about 85 lbs of alky @ 15 pounds of boost with my knob a little below 6.

But as you approach the top of the alky dial, the alky pressure does not increase as much per pound of boost as it did lower on the dial. Meaning, you are already close to the "most alky per pound of boost" limit when you pass the 7 on the knob.

This doesn't mean your limited to 75 or 80 or 100 PSI of alky. It only means that the changes are more subtle as you approach the top of the dial. Then once your boost hits the low-mid 20 PSI mark, your alky is all in no matter where the knob is.......as long as it's somewhere on the top of the dial.

As far as the maximum alky PSI output goes, this is not the issue. If the same dial position is used as a constant, small nozzles, big nozzles, double nozzles, big double nozzles, and small double nozzles will all change the pressure readings at the sensor. Example, a small single nozzle does not allow as much alky to flow as a large double nozzle at the same settings and pump speed. So, alky pressure will read much higher even though much less alky is being sprayed into the intake.

How's that Paul? Did I get that right?

Ok..I understand what he was trying to say now! Thanks Joe for taking the time to explain that for me! It makes SO much more sense now!!

 

[NY Twin Turbo]

In talking to Helo I took it that the pressure in the line is the same (when system is activated ) and the knob only controls the ramp up time to the full on.

Yes, it ramps up. So the pressure ramps up. Not like a regulated fuel system where the pressure differential between the intake and fuel system is a constant.

And this pressure will be different based on your nozzle/general plumbing set-up.

Another example. Take a garden hose and turn the spigot on full blast. Now squeeze the end. Let only a little water out and take a pressure reading at the hose and it will read about 70 PSI in New York. Now open the hose to full flow and take another pressure reading. You may get 20 PSI if your lucky.

The bigger the alky nozzle or nozzles at any point on the "ramp-up" the lower the pressure reading as compared to a smaller nozzle. However, when the pump is all-in full blast, pressure far exceeds open flow from the nozzles.

Now....................I can be totally and completely wrong about everything I have said in the last 2 posts if the alky kit has a closed loop logic that adjusts pump output based on feedback from a pressure sensor that in theory would compensates for larger nozzles.