HELP! High HP low TQ

[jason1320]

I finally got around to dynoing my car about two weeks ago and I found out something very interesting, my HP is 402.8 but my torque was only 351.7. In most other cases I have seen the torque is usually higher, what gives?

My only performance mods are a Magnaflow 2.5 inch catback and and CAI. One important note, the battery on my car has not been unplugged since I got the mods. Does anyone think that "clearing" the ECC might help?

The other problem is that my car seems to be running skinny in the lower RPM range. It doesn't even get safe until 5000 RPM's. I know a tune will help, but could a CAI and catback really lean it out this much? :shrug:

Attached are my dyno sheets.

 

[KenCobra03]

I have a Magnaflow catback and a K&N FIPK.
I have 402 RWHP and 369 RWTQ in my first
dyno, then 399 RWHP and 376 RWTQ in my
second pull.I think your hp is fine and torque
is a bit low, but your mods won't affect your
A/F ratio that bad.Catback by itself makes no
changes to A/F ratio.Do you have any other
mod done, or is your airfilter sucking in air
somewhere it shouldn't be, creating a lean
condition?

 

[jason1320]

I just checked it again, everything is tight. I have the negative battery cable off now. I won't be able to check the A/F but I may be able to notice more power. I'm about to go for a ride, I'll post when I get back.

BTW, I have no other engine mods. Everything else is drivetrain and suspension.

:??:

 

[Chonger]

You are way too lean in the midrange. It looks like 14:1. Are you using a densecharger? If not then what kind? Does it have a bend in front of the MAF?

 

[Rick@Amazon]

Removing battery terminal is not going to do much. Are you sure you were in open loop before the test? ECT must be at least 150 deg before you do the run. If you are tail pipe testing this could be another reason for the lean a/f. If you have a straight into the maf cai and the maf is at 10 o'clock you should not go lean. If you have any bends in the piping before the maf that could be your problem. Best to have a bung welded in before the cats to get a true a/f reading. Belt slip could also be the problem with low torque.

Rick

 

[jason1320]

Well I just got back from the run and maybe its just me but the torque felt alot stronger. When I first started the car the instruments went into test mode for a second, I then started the car and noticed some engine surging for a second. Once I reved it a couple of times it leveled off. (Has never done this before)

My CAI is a custom job done by a local shop. Espeut Performance in Landover MD. It is basicly a mandral bent elbow in front of the MAF with a HUGE K&N filter on the end of it shoved in to the fender well. Pete (the owner) has the same CAI on his car and it works fine.

The A/F was taken at the tailpipe on the third of three runs. It was done at Kaufmans in PA about two weeks ago.

 

[mike79]

YOu said you took off the negative cable for a while and then drove around for a while and it feels stronger? It could..doing that resets the computer and the car will run lean for a little while, giving you a bit more power.

 

[Chonger]

Do a search on the densecharger and you will see many people have had very similar problems with a CAI kit that has a bend in front of the MAF sensor. You can get totally different AF readings depending on the position of the MAF sensor. The bend can cause turbulance and mess up the readings.

Me personally, I would ditch the CAI kit and get a straight shot kit w/out any bends like K&N, Steeda, Amazon, etc. Try a dyno run w/the stock airbox back on and I bet you will be PIG RICH! A good CAI kit should not lean out your car.

 

[TRBO VNM]

Originally posted by Chonger
Do a search on the densecharger and you will see many people have had very similar problems with a CAI kit that has a bend in front of the MAF sensor. You can get totally different AF readings depending on the position of the MAF sensor. The bend can cause turbulance and mess up the readings.

Me personally, I would ditch the CAI kit and get a straight shot kit w/out any bends like K&N, Steeda, Amazon, etc. Try a dyno run w/the stock airbox back on and I bet you will be PIG RICH! A good CAI kit should not lean out your car.

Jason,

this is what I have been trying to tell you. Keep in mind, Pete has a custom tune. If you really want to find out, get to a dyno and do some testing. And Rick has a point about the temps. When we were at Kauffmans our cars sat for a while before they went on the dyno and once on the dyno they made the 3 pulls back to back.

the A/F was at the tailpipe. so subtract .5 point from your graph and that is about what it would be at the bung.

 

[PhillyCobra]

A few points:

With stock blower and pulley HP # is higher than torque because blower is still operating in an efficient state at high RPM (up to 6000) allowing HP to continue to build as revs rise. You only get real big torque numbers (bigger than HP) when you usse a small pulley and get a lot of boost and torque at low RPM, but loose torque as blower is overspun at high RPM, consequently dropping HP. In other words, there is decreasing volumetric efficiency at high revs, whereas the stock engine, with 4V heads, is still efficient at high revs, resulting in high HP. It's like a racing or high po motorcycle engine (say 100 lb ft torque and 175 HP).


However, I think there is something fishy with your A/F and dyno curves, with very different torque curve shapes on the 2 runs. I agree this can be from the bent CAI confusing the MAF. Or it could be a problem with the dyno (which I think is suspicious with the first run showing good output up to 6800, which is over the rev limiter! The 2nd run shows a more typical cutoff (and spark blowout) from 6200 to 6500 RPM.


Resetting the computer by unhooking the battery resets the A/F tables to stock, which could be either leaner or richer than they have been "trimmed" to through driving cycles. In other words, if your computer thought the engine was frequently running too rich, it would "trim" the A/F tables (including those at WOT) to be leaner. In that case, erasing the memory would result in a richer set up until the computer relearned. Problems with the MAF, leaky or sticky injectors, vacuum leaks and O2 sensors can frequently cause significant "trim" shifts in the computer.

I would definitely do a diagnostic code lookup in the computer after you've driven for a while and look for any possible errors. Would also ask the dyno operator about possible problems with his setup, including A/F measurement.

 

[DD2000GT]

Boy have I seen Dynos like that! You are too lean on the bottom end. Get your A/F ratio down to 13:1 by 3k RPMs and 12:1 around 3500 RPMs and you will see a huge increase on your torque numbers. Our cars make the peak torque down low, and this is where you are starving the engine.

Go to WWW.mafterburner.com and check out the 03 Cobra Before and After Dyno chart. That is my car, and look at the difference in low end torque by adding fuel. Your torque should jump up to peak, not arch up to peak.

Your problem is the same as mine, CAI in the fender. The bend in the pipe causes air swirling that causes noise in your MAF signal and throws off the readings. You need to either do as I did and get a device that will let you counter this affect, or get a straight pipe CAI. Do not run it like this for long if you care about the longivity of your car.

Good luck,
Dan

 

[CobraBob]

Speaking of dynos, I know someone in the area that went to Dyno A (locally) and found his A/F was too lean. He suspected the dyno sniffer was off (even though a new filter had been installed) and went to Dyno B (also local). Dyno B's A/F was more in line with what a third dyno (out of state). Lesson here. Not all dynos are created equal. Be sure you use a reputable dyno with an good operator.