The Most A Stock LS1 Can Take...
Teching In
Joined: Feb 2005
Posts: 8
Likes: 0
I have a completely stock engine,4L60E,PY 3600,250 dual stage NX MAF with 27 degrees timing and 116 VP fuel on a stand alone fuel system and ran a 10.77 with a 1.59 60 ft.in 95 degree weather and drive it 100 miles a week.NX is THE only way to go.By the way she weighs 3665 in race trim.
TECH Apprentice
Joined: Jun 2005
Posts: 337
Likes: 0
From: Michigan
Originally Posted by NC00Z28
I have a completely stock engine,4L60E,PY 3600,250 dual stage NX MAF with 27 degrees timing and 116 VP fuel on a stand alone fuel system and ran a 10.77 with a 1.59 60 ft.in 95 degree weather and drive it 100 miles a week.NX is THE only way to go.By the way she weighs 3665 in race trim.
Originally Posted by jimmyblue
This seems like it "should" work, but I question the
responsiveness of the IAT sensor to actual air temp
steps. Seems like the thermal time constant will make
the enrichment roll on slow; how slow, is too slow?
And of course this is a problem even with the 85mm
MAFs that have close-coupled (in-throat) thermistors.
The way some lids have the IAT off in a corner, you
really have to wonder how well (or whether) it will
track. How many frames does it take, from start of
spray to where IAT has reached its lower, stable
value again?
But there is also the idea of using a relay and resistor
to jack the IAT all the way over to -40F readings,
and then you have a free hand with fuel and spark
using that never-seen (for us folks south of the
Arctic Circle) column in the PE - Add vs IAT table
and the leftmost (14F) column in the IAT spark
adder as well. Though I guess the common thing
is just to hit the spark table in rows above the max
NA g/cyl seen, with some reduction.
From the Helm book it looks like you would want
a 100Kohm resistor, with a normally-closed relay
across it, coil driven by your 'noid line and the
shunted resistor put inline with the IAT sensor
signal wire. When the relay energizes 100Kohms
will be added to the IAT reading.
I know there are table(s) that index off both IAT
and ECT, such as the closed loop enable threshold.
You might find some second-order effects to chase
down using this scheme. But I think it's as close to
a "magic button" for the software to see, as you
can get.
This is about $5 worth of Radio Shack parts. Less
if you hoard the right junk. Maybe $8 if you put it
in a pretty little project box.
responsiveness of the IAT sensor to actual air temp
steps. Seems like the thermal time constant will make
the enrichment roll on slow; how slow, is too slow?
And of course this is a problem even with the 85mm
MAFs that have close-coupled (in-throat) thermistors.
The way some lids have the IAT off in a corner, you
really have to wonder how well (or whether) it will
track. How many frames does it take, from start of
spray to where IAT has reached its lower, stable
value again?
But there is also the idea of using a relay and resistor
to jack the IAT all the way over to -40F readings,
and then you have a free hand with fuel and spark
using that never-seen (for us folks south of the
Arctic Circle) column in the PE - Add vs IAT table
and the leftmost (14F) column in the IAT spark
adder as well. Though I guess the common thing
is just to hit the spark table in rows above the max
NA g/cyl seen, with some reduction.
From the Helm book it looks like you would want
a 100Kohm resistor, with a normally-closed relay
across it, coil driven by your 'noid line and the
shunted resistor put inline with the IAT sensor
signal wire. When the relay energizes 100Kohms
will be added to the IAT reading.
I know there are table(s) that index off both IAT
and ECT, such as the closed loop enable threshold.
You might find some second-order effects to chase
down using this scheme. But I think it's as close to
a "magic button" for the software to see, as you
can get.
This is about $5 worth of Radio Shack parts. Less
if you hoard the right junk. Maybe $8 if you put it
in a pretty little project box.
Robert
I am particularly going to pay ATTN to the advance at g/sec over NA cutoff .76 I will also be trying to dial in IAT vs PE and see if it is nozzle placement effects or secondary tables as mentioned. Well, rolling out to the track now. Great info in here.
On Topic for Original Issue:
I am setting my timing up, on dry, to pull the necessary timing once into the higher airflow region the nitrous will push. Also, I dont do too much of a curve. I set the initial timing, from my stall point to xx degrees, then for every two columns to the right I add ONE degree up to the max torque rpm. Max Tq likes rich and lower timing. Then I start adding one degree per column to the right of max tq up to the max hp/rpm. Almost all timing is in the .76 g./cyl row for NA. Currently my table starts at 22* at launch and ramps up to max of 26*, used for 175-200 shots, mix race gas and 93 pump in stock tank. AFR set the same curve design, needs a lil tweaking but should start around 10.5:1 at launch rpm vs g/cyl and lean out on a ramp to 12.7:1. Slight curve, smooth curve to avoid any tip in and etc.
On Topic for Original Issue:
I am setting my timing up, on dry, to pull the necessary timing once into the higher airflow region the nitrous will push. Also, I dont do too much of a curve. I set the initial timing, from my stall point to xx degrees, then for every two columns to the right I add ONE degree up to the max torque rpm. Max Tq likes rich and lower timing. Then I start adding one degree per column to the right of max tq up to the max hp/rpm. Almost all timing is in the .76 g./cyl row for NA. Currently my table starts at 22* at launch and ramps up to max of 26*, used for 175-200 shots, mix race gas and 93 pump in stock tank. AFR set the same curve design, needs a lil tweaking but should start around 10.5:1 at launch rpm vs g/cyl and lean out on a ramp to 12.7:1. Slight curve, smooth curve to avoid any tip in and etc.
Originally Posted by CAT3
I am particularly going to pay ATTN to the advance at g/sec over NA cutoff .76 I will also be trying to dial in IAT vs PE and see if it is nozzle placement effects or secondary tables as mentioned. Well, rolling out to the track now. Great info in here.
On Topic for Original Issue:
I am setting my timing up, on dry, to pull the necessary timing once into the higher airflow region the nitrous will push. Also, I dont do too much of a curve. I set the initial timing, from my stall point to xx degrees, then for every two columns to the right I add ONE degree up to the max torque rpm. Max Tq likes rich and lower timing. Then I start adding one degree per column to the right of max tq up to the max hp/rpm. Almost all timing is in the .76 g./cyl row for NA. Currently my table starts at 22* at launch and ramps up to max of 26*, used for 175-200 shots, mix race gas and 93 pump in stock tank. AFR set the same curve design, needs a lil tweaking but should start around 10.5:1 at launch rpm vs g/cyl and lean out on a ramp to 12.7:1. Slight curve, smooth curve to avoid any tip in and etc.
On Topic for Original Issue:
I am setting my timing up, on dry, to pull the necessary timing once into the higher airflow region the nitrous will push. Also, I dont do too much of a curve. I set the initial timing, from my stall point to xx degrees, then for every two columns to the right I add ONE degree up to the max torque rpm. Max Tq likes rich and lower timing. Then I start adding one degree per column to the right of max tq up to the max hp/rpm. Almost all timing is in the .76 g./cyl row for NA. Currently my table starts at 22* at launch and ramps up to max of 26*, used for 175-200 shots, mix race gas and 93 pump in stock tank. AFR set the same curve design, needs a lil tweaking but should start around 10.5:1 at launch rpm vs g/cyl and lean out on a ramp to 12.7:1. Slight curve, smooth curve to avoid any tip in and etc.
I'll be heading to the track Friday with my new clutch, but have to take it easy, as Textraila dosen't want me blasting the nitrous quite yet. Next Wed we'll start with some mondo launches and at least 1 stg and a half.
Robert
