When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
It seems pretty clear in the old dyno graph that it was running out of fuel. The new one looks really good. With torque at 365 lb/ft or more for the entire RPM range of the test, there is no speed at which this engine won't pull hard.
Yea the torque just takes a dive at about 4500rpm.
Based on the timing of when the original dyno test was done and when I picked the car up (it was smelling like gas from the get go), I believe the original regulator was failing during the dyno test...which I find hard to believe but there it is. The car ran great during December after I installed the second Holley regulator, seems to be even better. I suspect that the fuel pressure was off a bit. Also the Aeromotive unit appears to have a replaceable diaphragm...the Holley diaphragm was not replaceable, the entire unit had to be swapped.
Also looks like there is no point in winding it out much past 5800rpm.
Last edited by Jaye Bass; Feb 6, 2020 at 06:24 PM.
Also looks like there is no point in winding it out much past 5800rpm.
I was going to ask about that. It looks to me like that isn't the actual torque and power falling off hard, but rather that the dyno operator just stopped the test and let off the pedal at that point. Otherwise, something else seems to be going on to cause a drop that steep! ON EDIT: Is that just the redline programmed into the ECM kicking in? If so, you'd benefit from raising that and seeing how much more power it would build, because it really doesn't look like it was done.
Last edited by MatthewMiller; Feb 6, 2020 at 06:42 PM.
I agree with Matthew Miller looks like in the old dyno it ran out of fuel.
I also wonder if raising the redline a bit would get you a bit more power it lools to me like the dyno run was just ended rather than the engine nose diving at the end, or lile matt said maybe that was the rev limiter?
I was going to ask about that. It looks to me like that isn't the actual torque and power falling off hard, but rather that the dyno operator just stopped the test and let off the pedal at that point. Otherwise, something else seems to be going on to cause a drop that steep! ON EDIT: Is that just the redline programmed into the ECM kicking in? If so, you'd benefit from raising that and seeing how much more power it would build, because it really doesn't look like it was done.
Originally Posted by DMITTZ
I agree with Matthew Miller looks like in the old dyno it ran out of fuel.
I also wonder if raising the redline a bit would get you a bit more power it lools to me like the dyno run was just ended rather than the engine nose diving at the end, or lile matt said maybe that was the rev limiter?
It has the innards to go up to maybe 6200 or maybe a bit higher. I'll check with him when the weather warms up. It does look like they shut down the motor.
It has the innards to go up to maybe 6200 or maybe a bit higher. I'll check with him when the weather warms up. It does look like they shut down the motor.
Definitely do, because it was still building power. FWIW, a stock LT4 was rev-limited to 6400rpm from the factory in the stock PCM tune.