Stock Zr1 cam is a 211/230 @121 I believe... 
Cause for flat HP curve? Chart inside.
Thread Starter
TECH Regular
Joined: Dec 2003
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From: SOFLO
Cause for flat HP curve? Chart inside. After looking at my dyno for a couple days and comparing it to other combos, I've noticed the HP curve is relatively flat. Indication of restriction? What am I missing? (Little dip at the end was knock on this pull)
6.0 LQ Iron block 10.6 SCR
STOCK Rods, Pistons, Crank
STOCK 317 Heads w. springs, retainers
LS9 Gaskets
231/248 .617"/.595" 120+5
2.3 Whipple @13 lbs boost
102mm TB
E85
18° Timing
2" primary headers, 3" x-pipe merged into 2 1/2 magnaflows
Mustang DYNO
4l80E Trans w/ UNLOCKED converter (yank SC3000
Ford 9 Inch w/ 3.70 gear
Graph.
6.0 LQ Iron block 10.6 SCR
STOCK Rods, Pistons, Crank
STOCK 317 Heads w. springs, retainers
LS9 Gaskets
231/248 .617"/.595" 120+5
2.3 Whipple @13 lbs boost
102mm TB
E85
18° Timing
2" primary headers, 3" x-pipe merged into 2 1/2 magnaflows
Mustang DYNO
4l80E Trans w/ UNLOCKED converter (yank SC3000
Ford 9 Inch w/ 3.70 gear
Graph.
Thread Starter
TECH Regular
Joined: Dec 2003
Posts: 405
Likes: 1
From: SOFLO
I cannot see the link but it is possible there is an inlet restriction to the blower. I know the LS9 and LSA blowers benefit quite a bit from porting the snout.
That split isn't all that unusual if you look at the LS9 cam. It just has more duration on the int and exh.
The 2.5" magnaflows may be causing it.
That split isn't all that unusual if you look at the LS9 cam. It just has more duration on the int and exh.
The 2.5" magnaflows may be causing it.
Thread Starter
TECH Regular
Joined: Dec 2003
Posts: 405
Likes: 1
From: SOFLO
I cannot see the link but it is possible there is an inlet restriction to the blower. I know the LS9 and LSA blowers benefit quite a bit from porting the snout.
That split isn't all that unusual if you look at the LS9 cam. It just has more duration on the int and exh.
The 2.5" magnaflows may be causing it.
That split isn't all that unusual if you look at the LS9 cam. It just has more duration on the int and exh.
The 2.5" magnaflows may be causing it.
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Verdad Gallardo CRAZY amount of neg overlap on the ZR1 cam. 49* just seems like too much even for a stock car.
I would expect a restriction to show up with an accelerating dropoff rate for the torque (the restriction should get exponentially worse with RPM), the rate of fall-off seems to be less than near the beginning.
What computer are you using, stock PCM?
Is the 18 degrees only near redline and reduced in the middle (could explain the shape difference I'm seeing).
A positive displacement blower should move relatively the same amount of air into the engine for each combustion event so really the shape of the curve should nearly match the shape of your engines VE curve....so if you want more top end torque/hp you would look to improve top end VE (including entire intake and exhaust system), while realizing restrictions in areas of vacuum are significantly worse than in areas of positive pressure. (back of a car has more drag than the front for the same reasons)
What computer are you using, stock PCM?
Is the 18 degrees only near redline and reduced in the middle (could explain the shape difference I'm seeing).
A positive displacement blower should move relatively the same amount of air into the engine for each combustion event so really the shape of the curve should nearly match the shape of your engines VE curve....so if you want more top end torque/hp you would look to improve top end VE (including entire intake and exhaust system), while realizing restrictions in areas of vacuum are significantly worse than in areas of positive pressure. (back of a car has more drag than the front for the same reasons)
That's a normal whipple graph? Uhh no. An unlocked torque converter will not give you a real representation of the engine's powerband. In other words it wouldn't look like that if it were locked. There are so many variables that could cause one thing or another in the tune, the combo, etc that you can't really compare like that anyways.
Thread Starter
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Joined: Dec 2003
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From: SOFLO
Pull was started @ 3500 RPM's.
Some have mentioned that the guy driving hammered the pedal WOT instead of rolling into it which caused the initial spike in torque.
Also, the log indicated the engine was revving to 6500 RPM vs. the 6000 RPM shown on the graph.
So far I have heard the mufflers are small, heads are holding it back, and the trans/converter might be slipping.
Some have mentioned that the guy driving hammered the pedal WOT instead of rolling into it which caused the initial spike in torque.
Also, the log indicated the engine was revving to 6500 RPM vs. the 6000 RPM shown on the graph.
So far I have heard the mufflers are small, heads are holding it back, and the trans/converter might be slipping.
Pull was started @ 3500 RPM's.
Some have mentioned that the guy driving hammered the pedal WOT instead of rolling into it which caused the initial spike in torque.
Also, the log indicated the engine was revving to 6500 RPM vs. the 6000 RPM shown on the graph.
So far I have heard the mufflers are small, heads are holding it back, and the trans/converter might be slipping.
Some have mentioned that the guy driving hammered the pedal WOT instead of rolling into it which caused the initial spike in torque.
Also, the log indicated the engine was revving to 6500 RPM vs. the 6000 RPM shown on the graph.
So far I have heard the mufflers are small, heads are holding it back, and the trans/converter might be slipping.
He may have pulled it to 6500 rpms but the dyno stopped at 6000 rpms for potentially many reasons
The problem with a mustang dyno is that what it reads is up to the operator. It could be something as simple as operator error but I'm kind of failing to see the problem with the graph other than the dip up top which you already said was knock retard (not sure how it's pinging at 18 deg on E85 at that boost level/comp however).
Is there something in particular you have an issue with? Post up the log file showing what happened on that dyno pull because without it people are just shooting in the dark for something that may not even be a problem. What did timing start out at 3500 rpm vs redline? I'm assuming it has a ramp to it.