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Discussion Starter · #1 ·
Car was fbo,ported blower,heads,cam,meth/93, made 757rwhp/723rwtq. 23.5° of timing
Temp was approx 70°

1 yr later

the only thing that changed this time is the fuel,
Using MS109

added 4.5° Of timing

car dynod 738rwhp and 690rwtq. At 28° of timing
the baseline pull was 730rwhp and 650rwtq

so the gains were 8rwhp and 40rwtq...
Temp was approx 55°

I understand the dyno is a tool, which the baseline is helpful to determine a gain.

my question is what would cause such a drastic drop in performance?

how would adding timing gain so much tq and next to no hp?
 

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Do you have any datalogs to compare something like 60 to 130 times? If it's the same dyno, maybe you had higher IAT.
 

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Discussion Starter · #3 ·
Do you have any datalogs to compare something like 60 to 130 times? If it's the same dyno, maybe you had higher IAT.
I have a couple 60-130’s from last season on 93/meth

I was going to wait until it was nice weather and try it out and compare. But other than that I have nothing.
 

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Would be a good comparison to see the 93/meth run again on the dyno after the 109. Could be that your setup isn't really benefitting from the 109 fuel.
 

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Discussion Starter · #6 ·
Would be a good comparison to see the 93/meth run again on the dyno after the 109. Could be that your setup isn't really benefitting from the 109 fuel.
I wish I knew more about tuning. I thought adding timing would net some sort of increase in power as long as knock is avoided.

if this is the case then I’ll be going back to the 93/meth combo.
 

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Car was fbo,ported blower,heads,cam,meth/93, made 757rwhp/723rwtq. 23.5° of timing
Temp was approx 70°

1 yr later

the only thing that changed this time is the fuel,
Using MS109

added 4.5° Of timing

car dynod 738rwhp and 690rwtq. At 28° of timing
the baseline pull was 730rwhp and 650rwtq

so the gains were 8rwhp and 40rwtq...
Temp was approx 55°


I understand the dyno is a tool, which the baseline is helpful to determine a gain.

my question is what would cause such a drastic drop in performance?

how would adding timing gain so much tq and next to no hp?
It simply appears the engine liked the fuel and additional timing.

Best Engine VE% is at 'Peak Torque'.

But then the VE% begins to fall, even though mass flow is
increased in order to meet the increased mass flow demands
placed on the engine at higher engine rpm.

However, as the mass flow is increased at higher engine rpm,
your VE% is decreasing all the while.

If one can improve the VE% at the higher engine rpm, then
one will also produce more HP at the higher engine rpm.

The engine produce about the same rwHP, more or less, so
we can assume the Engines VE% is being reduced as the
cylinder head moves into either velocity choke, or turbulence,
at or around some given engine rpm.

So let's now move back to 'Peak Torque', where we have best VE%.

Peak Torque, not Peak HP, is where the engine generates the most cylinder pressure.
At 'Peak HP' engine rpm, we have the most airflow / mass flow.

So at peak torque we 'Must' tune around that peak pressure,
which requires sufficient fuel, in order to set the timing for
Maximum Brake Torque, or what is simply called 'MBT'.

Cheers,
RD
 

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Discussion Starter · #8 ·
Even though there was a gain from the baseline pull, the previous dyno (same dyno about a year apart) was much higher. I don’t understand tuning but it seems I was better off on the 93/meth. Unless of course a new 60-130 time emerges. That’s the only documentation I have..
 

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It simply appears the engine liked the fuel and additional timing.

Best Engine VE% is at 'Peak Torque'.

But then the VE% begins to fall, even though mass flow is
increased in order to meet the increased mass flow demands
placed on the engine at higher engine rpm.

However, as the mass flow is increased at higher engine rpm,
your VE% is decreasing all the while.

If one can improve the VE% at the higher engine rpm, then
one will also produce more HP at the higher engine rpm.

The engine produce about the same rwHP, more or less, so
we can assume the Engines VE% is being reduced as the
cylinder head moves into either velocity choke, or turbulence,
at or around some given engine rpm.

So let's now move back to 'Peak Torque', where we have best VE%.

Peak Torque, not Peak HP, is where the engine generates the most cylinder pressure.
At 'Peak HP' engine rpm, we have the most airflow / mass flow.

So at peak torque we 'Must' tune around that peak pressure,
which requires sufficient fuel, in order to set the timing for
Maximum Brake Torque, or what is simply called 'MBT'.

Cheers,
RD
Raising my hand:
Bruce didn't you tell me something about "corn" (not in this case though) and Meth being cooler fuels? More Octane wouldn't necessarily be cooler, right?

So might that hotter fuel influence negatively the performance?
 

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Raising my hand:
Bruce didn't you tell me something about "corn" (not in this case though) and Meth being cooler fuels? More Octane wouldn't necessarily be cooler, right?

So might that hotter fuel influence negatively the performance?
Pressure causes heat, and conversely, heat causes pressure.

Self detonation is caused by the heat rising within the cylinder
on the compression stroke / cycle.

Once the heat becomes sufficiently high, the mass charge detonates
without the aid of the spark plug.

-gasoline-
Higher octane levels do not stop detonation.
Higher octane levels only delay self detonation.

-oxygenated fuels-
Oxygenated fuels release oxygen within the cylinder and carry
a very high 'Latent Heat of Evaporation'.

-using E85 as an example-
This means that when E85 is used as fuel, it goes through
a change from liquid to gas, and during this process it
absorbs a lot of heat from the intake & cylinder charge.

A colder intake / mass charge is denser and improves power.

This is because as the density goes up, the mass charge
or weight of the mass charge increases. This means we
have been able to add both air and fuel, which in essence,
is the 'Mass Charge'.

Meth is even better at doing the above.

Therefore, when one uses E85, and also sprays with Meth,
one should be able to increase the timing even more while
searching for MBT, until the timing s set for optimum MBT.

E85 is great 'Street Racing' fuel that is very economical
even though its quality varies all the time.
***best to get a test kit. . . .

Meth is much better and it has been know to completely
replace intercoolers in some cases. Although I would not
attempt that with this engine platform..lol

Cheers,
Bruce
 
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Discussion Starter · #11 ·
I’m still using meth, just replaced the 93 with the ms109. I just have a gut feeling that I went backwards
 

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I wish I knew more about tuning. I thought adding timing would net some sort of increase in power as long as knock is avoided.

if this is the case then I’ll be going back to the 93/meth combo.
Engine Knock, or self detonation (not preignition) happens as
cylinder pressures increase as I noted above.

This usually happens at or around peak torque engine rpm,
which is also at a much lower lower engine rpm than peak
fwHP Engine RPM. . . .

Because the engine is turning slower, and the heat and pressure
are climbing as well, the engine then has more 'Time' to self detonate,
as RPM, is simply another way to characterize 'Time'.

Can an engine also have knock at higher engine rpm. . .Yes!
But it is most common at the lower engine rpm for the reasons I noted above.

Cheers,
RD
 

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I’m still using meth, just replaced the 93 with the ms109. I just have a gut feeling that I went backwards
You wrote:
"car dynod 738rwhp and 690rwtq. At 28° of timing
the baseline pull was 730rwhp and 650rwtq

Being up 8 rwHP, and up 40 lbs.feet of torque my friend, is not going backwards..lol
Please remember; horse power is simply torque multiplied by engine rpm. . . . .

---------------------------------------------------------------------------------------

Here you go:
Torque is king for the simple fact that Torque is what does the work.
Torque is measured, HP is calculated.

We can increase Torque with VE or displacement, or we can multiply
it with rpm and gears, but Torque is always the force doing the work.

HP just gives it a time factor, which is related to engine rpm as I wrote above.

Cheers,
RD
 

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Discussion Starter · #14 ·
You wrote:
"car dynod 738rwhp and 690rwtq. At 28° of timing
the baseline pull was 730rwhp and 650rwtq

Being up 8 rwHP, and up 40 lbs.feet of torque my friend, is not going backwards..lol
Please remember; horse power is simply torque multiplied by engine rpm. . . . .

---------------------------------------------------------------------------------------

Here you go:
Torque is king for the simple fact that Torque is what does the work.
Torque is measured, HP is calculated.

We can increase Torque with VE or displacement, or we can multiply
it with rpm and gears, but Torque is always the force doing the work.

HP just gives it a time factor, which is related to engine rpm as I wrote above.

Cheers,
RD
That was with the 109/meth.

last year on 93/meth it put down 757rwhp/723rwtq.

this is what I meant about going backwards.

the base pull on the 109 was 70+ ftlbs less than last year
 

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-brake mean effective pressure-

With the assumption that it's a 4-stroke engine, the BMEP is simply the torque
divided by the displacement and multiplied by a units-conversion constant.
***a quick search of the internet regarding what is BMEP will give many results.

With the above in mind here is an overview of BMEP.
BMEP = Brake Mean Effective Pressure, or the amount of average
Cylinder Pressure necessary to create the calculated HP and Torque

HP and Torque are related thru BMEP, as well as the CID (cubic inch ).

HP = Torque * RPM / 5252

BMEP = ( Torque * 150.8 ) / CID

BMEP = (HP * 792000) / ( CID * RPM)

5252 = 792000 / 150.8

150.7964474 = Pi * 4 * 12 inches

5252.113122 = 33000 Ft-Lbs-Minute / ( Pi * 2)

Cheers,
RD
 

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That was with the 109/meth.

last year on 93/meth it put down 757rwhp/723rwtq.

this is what I meant about going backwards.

the base pull on the 109 was 70+ ftlbs less than last year
Quoting from your original post:
"car dynod 738rwhp and 690rwtq. At 28° of timing
the baseline pull was 730rwhp and 650rwtq"

If the above quote was for the MS109, then. . .
I misinterpreted what your best was..lol

I think the name of the thread 'Lost HP but Gained Torque'
most likely played a role in my confusion. . .But the Wife
would say. . ."no, not necessarily so..lol

Assuming there is nothing else(?) related, then yes,
your engine seems to like the fuel mix you had
previously used.

Tuning for MBT is not easy, especially on these engines,
as they have a 'Fast Burn' cylinder head. . .

Glad we got that straightened out. .:giggle:
 

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Could the fast burn cylinder head and a slower burning fuel cause the lower peak numbers? Just curious
 

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was it ran up first with the same timing in it ? and if so was it ran just once or a few times ? i usually see that it takes a good 2-3 full runs to start to get consistent data on some dynos
 

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Discussion Starter · #19 ·
was it ran up first with the same timing in it ? and if so was it ran just once or a few times ? i usually see that it takes a good 2-3 full runs to start to get consistent data on some dynos
It was ran a total of 5 times. So yes, 3 pulls were fairly consistent.

I should add the dyno location moved about 20 min away from the previous location. It’s a dyno jet on a trailer..
 

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It was ran a total of 5 times. So yes, 3 pulls were fairly consistent.

I should add the dyno location moved about 20 min away from the previous location. It’s a dyno jet on a trailer..
does the dyno have its own weather station to offset changes ? that makes a big difference if its not adjusted properly throughout the day it will have different outputs, if a weather station is used with it then it adjusts for the offsets to keep all runs to the same base level so u get a more accurate reading in all conditions
 
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