850 Dyno Pulls (2.4L Non-Turbo)
850 Dyno Pulls (2.4L Non-Turbo)
8/10/19 Straight Pipe (w/ Cat) + IPD Filter
Low results... The dyno they use is an AWD Superflow WinDyn "Heartbreaker" style dyno (usually reads around 20% lower than a dynojet) that reads WHP. Put down a pretty terrible 61.6 WHP at 6000 rpm and 65 ft/lbs between 2500-5000 rpm. What I didn't know going in was that you are meant to run the car around for a while or warm it up on the dyno prior to making pulls. (Coolant was up to temp, but oil and transmission fluid weren't, increasing losses) Engine has good compression (around 190 psi on each cylinder), new-ish plugs, wires, distributor cap/rotor, etc. I'm going to do a full stage zero and put a muffler back on it. (Thinking the cat-only exhaust system may be a detriment to exhaust scavenging)
Any other ideas tune up wise as to the cause of the low output?
Low results... The dyno they use is an AWD Superflow WinDyn "Heartbreaker" style dyno (usually reads around 20% lower than a dynojet) that reads WHP. Put down a pretty terrible 61.6 WHP at 6000 rpm and 65 ft/lbs between 2500-5000 rpm. What I didn't know going in was that you are meant to run the car around for a while or warm it up on the dyno prior to making pulls. (Coolant was up to temp, but oil and transmission fluid weren't, increasing losses) Engine has good compression (around 190 psi on each cylinder), new-ish plugs, wires, distributor cap/rotor, etc. I'm going to do a full stage zero and put a muffler back on it. (Thinking the cat-only exhaust system may be a detriment to exhaust scavenging)
Any other ideas tune up wise as to the cause of the low output?
Last edited by Luke Woessner; Aug 10, 2019 at 06:39 PM.
Super Moderator
Joined: Mar 2012
Posts: 9,601
Likes: 540
From: Burlington, VT
generally speaking the conversion from crank HP to wheel HP is 80% so for an NA with 160 HP I'd expect Wheel HP in the 120 to125 range.
Another good way to guessitmate HP is the "trap speed" in a 1/4 mile. If your car is still able to get to say 85 mph by the end of a measured 1/4 mile, you are producing close to the published 160 HP and not the 80 HP your dyno test is suggesting whcih would map to a trap speed of 70 MPH.
So this test can help you determine if the dyno test was done correctly or if your car is actually serverely out of tune. Things that can throw off your HP measurement include an intake air blockage (really clogged filter etc), crimped exhaust, poor spark (old wires/rotor/cap) poor fuel pressure, incorrectly adjusted throttle linkage are a few things that come to mind. Stuff like a bad O2 sensor would likely throw a check engine light...
Another good way to guessitmate HP is the "trap speed" in a 1/4 mile. If your car is still able to get to say 85 mph by the end of a measured 1/4 mile, you are producing close to the published 160 HP and not the 80 HP your dyno test is suggesting whcih would map to a trap speed of 70 MPH.
So this test can help you determine if the dyno test was done correctly or if your car is actually serverely out of tune. Things that can throw off your HP measurement include an intake air blockage (really clogged filter etc), crimped exhaust, poor spark (old wires/rotor/cap) poor fuel pressure, incorrectly adjusted throttle linkage are a few things that come to mind. Stuff like a bad O2 sensor would likely throw a check engine light...
Thread
Thread Starter
Forum
Replies
Last Post