Well, I just had my car dyno-tuned at a well known and trusted shop here in Kansas City. The tuner dialed in my car's AFR to 13.1 and tweaked a handful of PCM settings (such as disabling CAGS, setting fan temps, etc). Overall, they were very helpful and very knowledgeable.

The LS1-Edit tuning took care of the knock issues my car was seeing, but sadly the car didn't pull anywhere close to the numbers I was hoping for.

Today my car could only muster 339rwhp/341rwtq SAE after tuning. The tuner said he could only get within 2 degrees of optimum spark advance because otherwise the car would start detecting knock and retarding timing.

Given my untuned #s from April were 334rwhp/354rwtq SAE, I'm disappointed in these results; especially considering the cost of everything. The tuner was baffled as well because he expected to see more TQ out of the car given the mods. He did mention that today's weather conditions do have a slight impact because the dyno doesn't take humidity levels into consideration (???).

I'm at a loss for what could be wrong; any ideas?

EDIT: The car just passed 30k on the odometer and is still running on the original plugs (which were okay when I did the header install two months ago). Also, even given the lower-than-expected dyno numbers, the car pulls hard throughout the RPM range.

Here's the graph of the post-tuning numbers, with links to previous ones below:


Previous dyno sheets
Blackwing + Stingers + Smooth Coupler + LGMs (untuned)
Blackwing + Stingers + Smooth Coupler (untuned)
Baseline Dyno

 

Trying to compare dyno numbers from one dyno to another is only going to lead to confusion or anger or both. Every dyno has a unique personality.

340 rwhp for a Intake + LT car is right on par.

Mark

 

All your dyno sheets appear to be SAE corrected, which is good. However, the MC Racing readout also has smoothing applied, which gives a much more accurate result. If you don't apply smoothing, you pick up momentary horsepower and torque spikes, which, though the numbers may look impressive, aren't a real indicator of where you're at. I always look to make sure that SAE correction, and smoothing, was applied to any readout I use for comparative purposes. Just MHO.
Ed

 

From 327.5 RWHP/ 344.1 RWTQ with the Blackwing and a smooth air coupler. Then add LGMs headers, at about $1800.00 plus install unless you installed them yourself, get the car tuned at around $200-$400 more and wind up with 339rwhp/341rwtq

A gain of 11.5 RWHP and a loss of 3.1 ft/lbs of RWTQ.

I would have been pi$$ed at first too, but you know what......

Don't worry about your dyno results. Take it to the track.

Not pointing at you, certainly not pointing at you, but I don't know what it is, but too many guys with LGs like to flash dyno numbers.

Then when someone buys them and does not get the fancy "most powerful header in the world" dyno numbers they think they should have gotten, they are disappointed.

Take it to the track. Enjoy your headers and quit looking at those damned graphs. Your headers are well built and a quality piece and that is saying a lot. No one races on a dyno.

 

I'm very happy with my LG Pro LT Header System. See page 2 of my website for plenty of dyno graphs, especially the one that shows second visit to LGM for LT install yielded 350.4RWHP/363.8RWTQ.

 

very nice flat torque curve though. I dont think its a good idea to be at 13:1 the entire rpm band though.

Dave

 

Especially since temp on the dyno sheet says 90.9

 

Well yeah, I guess thats looking on the bright side. But he had a nice flat torque curve when he had just the Blackwing and Stingers.

 

my dyno w/ dynatech headers, vararam and 4.10s before tuning:



Dave

 

also the only reason your torque untuned was so high was because of that little spike at 3900 RPMS> Before and after it never gets above 350 Ft/lbs it doesnt seem. It just seems some spikes are spewing your baseline and before tunes. If you smooth those i bet you'd see better increased.

Dave

 

The spikes gave you erroneous initial readings. This would not have happened if it had been smoothed.
Ed

 

I am suprised at your results and I would be dissappointed also. LG headers are not cheap and a lot of people including myself talk them up quite a bit. I hope you see better results at the track. Do you have the catted version? If so, is it before the x-pipe or after? How long did you drive the car with the headers and no tune. Running rich for 2 months could have fouled out the plugs. I also noticed the power drops off around 5700 rpm which is not characteristic of these headers. Do you have different gears?

 

Hi,

The coupes have some timing tables that need to be changed to eliminate the tendency to pull timing out. On one of your graphs it shows to be very rough which could indicate the timing issue. It is probably not knock but some other parameters causing the timing to be pulled.

Many people have problems when they use two different dyno to compare. Too many variables.

Next, we don't like to use the same plugs after a header install because they get banged around and take a beating, even if they were removed during the install. In general, we just don't like using them especially with 30k on them.

The other thing that pops up is the air temp. Not because it will make less hp but because it will affect the correction factor if the air temp going in the engine is measured on one dyno and just room temp is measured on the other dyno. If the air temp on two dynos is measured in different places then the numbers will be different also.

Also, Hood open/hood closed??

If you want to email me a copy of your tune, I will check it out for you and let you know if I see anything unusual. We don't have the timing problem that you speak of.

Also, after you change the plugs goto the same dyno that you used before.

Give me a call if I can help.

Thanks
Lou gigliotti LGM
972-429-1963

 

Thank you to everyone who replied.

To those who asked, I'm running with all 4 02 sensors, thus the catalytic converters are located between the LTs and the x-pipe. The setup has not caused the PCM to throw any PCM codes.

Lou, thank you for the offer. I'm going to see if my tuner will give me the LS1 Edit file for my car so that I can e-mail it to you. I don't anticipate any issues in obtaining the file.

I'm wishing I had replaced the plugs when I installed the headers. I got in to much of a hurry and left the OEM in place. Regardless, I picked up a set of NGK TR55 plugs this morning, which I plan on installing next weekend. I'm also going to do MSD plug wires while I'm in there.

More to come.

 

Lou just made a good point. if your IATs are 104deg at WOT the ECM will pull timing. Not sure how much of a difference a degree or two will make (it didnt make much of a difference on mine but still).at 113IAT it will pull 2 deg, at 122 3 deg etc etc.

Also ECT over 230 pulls timing. If you have a stock fan setting you may very well be exceeding that. YOu need to see what your actual timing was. or give me your IAT and ECT and I can tell you what commanded Advance should be (pending no Knock learn factors)

Dave

 

Replaced my plugs when my LTS went on too. Lou will take good care of you too Good luck and I am sure you will get it done. I gained 35 RWHP and 35 TQ with LT Pro LGs, and dropped over .4 at the track and 4 MPH
Dave

 

What plugs did you put in it? How many miles did your old ones have?

 

Looks a little low to me...

See sig for my results... So far, it runs like a ****.

 

You will feel much better once you get to the track and see how well it runs! You said it felt stronger, and I bet you will be happy with your new ET and MPH. The track will speak louder than comparing dyno sheets from two different places.

 

I'll also add that it made absolutely no sense for your tuner to not have performed a base-line dyno before the tune.. You already have the car strapped down, it's really no extra effort at all. Smells like a tuner with "something to hide", i.e. didn't want you to find out that your $400 tune only netted you 5HP, or similar.

Would have also put your mind to rest as to the differences in the dyno readings. Too late now I suppose.

Seems like you are in the ball park when compared to a similar setup (EB20003). I agree that maybe your initial dyno runs were optimistic.