Boom Baby!!!

[TomsSVX]

i am not looking to run 12psi anymore on a stock motor. Now I am looking to drop the CR so I can run 12 psi and maybe more... 12psi is just too much and that was causing the detonation. The map was right, the motr just couldn't handle it

Tom

[oab_au]

The turboed 4 cylinder engines don't seem to have the same problem with detonation at their high boost levels.

This engine should have no problem using 14psi, if the fuel type, and spark timing is right.

Harvey.

[TomsSVX]

is the 4 cyl a 10:1 CR?? is it a twin screw blower mounted on the intake?? Realize that the charge we are send is hot and not abient and you will see why this motor cannot handle 12psi

Like I said, I was hearing audible knock at 0* of ignition...

Tom

[Trevor]

Originally Posted by oab_au

The turboed 4 cylinder engines don't seem to have the same problem with detonation at their high boost levels.

This engine should have no problem using 14psi, if the fuel type, and spark timing is right.

Harvey.

The inclusion of, "if the fuel type is right", makes the above statement completely nebulous. What is the intended point of interest?

[TomsSVX]

I have noticed that too but who really wants to run around on race fuel?? that **** is expensive!!!!

Tom

[oab_au]

Originally Posted by TomsSVX

I have noticed that too but who really wants to run around on race fuel?? that **** is expensive!!!!

Tom

No just normal high octane. The temp of the charge is not a problem, it is no where near the turbo temp, even with a inter cooler.

You say "I was hearing audible knock at 0* of ignition..." How do you know that the was the timing at that point. That was obversely not the total timing. As there is no way you can get knock with the spark set at TDC. the combustion volume is getting larger then.

I am not trying to start an argument, or trying to be smart, Tom, I would like to see you all have success.
I am just saying that, if you don't find and fix the problem that caused this failure, you will just send the next engine into the money pit.

Harvey.

[Trevor]

Originally Posted by oab_au

No just normal high octane. The temp of the charge is not a problem, it is no where near the turbo temp, even with a inter cooler.

You say "I was hearing audible knock at 0* of ignition..." How do you know that the was the timing at that point. That was obversely not the total timing. As there is no way you can get knock with the spark set at TDC. the combustion volume is getting larger then.

I am not trying to start an argument, or trying to be smart, Tom, I would like to see you all have success.
I am just saying that, if you don't find and fix the problem that caused this failure, you will just send the next engine into the money pit.

Harvey.

There will be no argument when statements are accurate and specific, as is expected from an "engineer". The conclusion is obvious.

[Phast SVX]

Originally Posted by oab_au

No just normal high octane. The temp of the charge is not a problem, it is no where near the turbo temp, even with a inter cooler.

You say "I was hearing audible knock at 0* of ignition..." How do you know that the was the timing at that point. That was obversely not the total timing. As there is no way you can get knock with the spark set at TDC. the combustion volume is getting larger then.

I am not trying to start an argument, or trying to be smart, Tom, I would like to see you all have success.
I am just saying that, if you don't find and fix the problem that caused this failure, you will just send the next engine into the money pit.

Harvey.

No were near turbo temp? oh harvey, i know you know better then to say this.....

[Phast SVX]

and of course he means ignition advance, what else would you take that for? if you wanted to make an argument, the only route would be that he is blowing out the spark.....Sorry im pissy tonight

[TomsSVX]

excuse me for the confusion. Under full retard(10*) I was actually at 8* because it should have been at 18* from what I understand. It was not actually 0* just on full retard

Tom

[cdigerlando]

Originally Posted by oab_au

The turboed 4 cylinder engines don't seem to have the same problem with detonation at their high boost levels.

This engine should have no problem using 14psi, if the fuel type, and spark timing is right.

Harvey.

Most folks who turbocharge the old pre 2002 4 cylinder RS's, which have the same or slightly lower compression, only go to about 7 or 8 psi on high octane safely. This is with a turbocharger and some are intercooled. Some folks go to 10 psi but it is shakey, unless you have forged internals. At that point most folks just lower the compression if they change out to forged internals. Check Nasioc. There is a lot of aftermarket turbo discussion. Even some supercharger discussion. I have heard of folks going to 10 psi with a turbo on our engine. That was with race fuel.

[cdigerlando]

Originally Posted by TomsSVX

excuse me for the confusion. Under full retard(10*) I was actually at 8* because it should have been at 18* from what I understand. It was not actually 0* just on full retard

Tom

I had major EGT trouble at this low of timing. I had to raise the timing significantly. I ran a map similar to what LAN came up with. I registered some possible predetonation noise on my logs, and slightly backed off on a couple of points, but I never seemed to have problems at this high of timing. Nothing audible. But hey, I have blowby now so who knows.

[oab_au]

I have looked back through the Supercharger thread to try to find what the ignition timing
is for the set up that TomSvx was using when Boom happened. As far as I can find.
TomSvx says it was 18*BTDC (if I read you right Tom), and the knock routine pulls 10 *
off that.

Tomfiles, says he saw 39 to 49* on light throttle (can’t believe Tom would be on light
throttle) , don’t know if this is the same chip?. There has to be an advance problem, for
detonation to cause the second ring land to break.

I say 14lbs is attainable on this engine, but it has to be handled right. As an example, way
back in 65, when you all were kids , I blew a side valve engine to 14 lbs with a Roots
Blower, when the fuel octain rating was a lot lower than it is now, and the side valve
combustion chamber was far from ideal for high compression.

The way I handled it was to leave the standard spark advance, to operate as normal, till
boost came up. At 2psi the vacuum advance, acted as a vacuum retard to pull the timing
back to the 10* static setting, it stayed at this, while there was boost.. At 7lbs the water
injection started, running water into the carb throat, proportional to the boost level. I have
no idea what the output was, but at least twice as good as standard, this car did daily
duties, running the kids to school, shopping, etc. The only trouble that it had in 4 years,
was two blown head gaskets, due to the rather large circumference of the combustion
chamber.

The way I see the set up you are using, is that it does not recognise boost, working only
with, air mass through the MAF, and rpm, does not tell what is happening in the
combustion chamber. You only know if it knocks, it is too late then.

With all the modern gear that is now available to us to adjust all the inputs of fuel, spark,
and knock. It should be possible to have 14lbs as a top pressure, but adjusted to rise with
engine speed, starting at 2000 rpm, say 5lbs, to rise to 14 by 3500 rpm.
An engine can use more boost pressure as the rpm rises. Too much at low rpms will
detonate heavily due to the time that the piston contains the combustion chamber steady,
while combustion pressure increases rapidly.

The one all saving action that can be taken is to inject water. There is absolutely no
chance of detonation when water is used properly. I think a MAP sensor should be used
to recognise boost, and the spark and water controlled off that, instead of relying on the
MAF and rpm. I know Lan, wants to keep the MAF as the one, to base the fuel on, so it
can still be used for that, the MAP can just be for the spark correction and water injection.
He has an extra switchable map for 87 octane. This map could be a boost map that the
MAP sensor could switch to when boost is detected.

Harvey.

[Trevor]

The way I handled it was to leave the standard spark advance, to operate as normal, till boost came up. At 2psi the vacuum advance, acted as a vacuum retard to pull the timing back to the 10* static setting, it stayed at this, while there was boost.

The way I see the set up you are using, is that it does not recognise boost, working only with, air mass through the MAF, and rpm, does not tell what is happening in the combustion chamber. You only know if it knocks, it is too late then.

Surely “air mass through the MAF”, must translate too boost pressure. Is not the the specific object of forced induction, to increase the mass of the air flow, over a given lengthy of time?

What is more, likewise the signal also translates the amount of charge induced into the cylinder, to become compressed within combustion the chamber; i.e. all of that, other than ignition and fuel values, which is involved in detonation.

[TomsSVX]

but why? I mean, you are spending 7500 on a S/C kit to run 9psi. If you want more power, build a motor for more power. I have never been affectionate to band-aide solutions such as water injection and that why I never put my injection kit on the car. If you want to make real power, make a real motor. Harvey, seriously take a look at a piston from and EG33 and you will see why the second land broke... I couldn't believe how thin the material is on the top/bottom of the piston(if it is laying in the motor) Just looking at them wrong could break it Thats is why I am going with beter pistons. The lower end is getting built to handle more power because... why would you build a suspension bridge to hold it's minimum weight?? You build it to hold more in the event the weight is exceeded and just for safe measure. The heads are going to be built because we cannot clear the combustion chamber quickly enough with the cams we have AND/OR we are experiencing valve float... There should be no reason for a MAP since boost should be programed. If you are at a certain throttle at a certain RPM... you will make X amount of pressure or vacc. With a PD blower it is constant which makes it much easier to tune than say a turbo car

Tom