OK, I'll be the first to admit that I don't know that much about modding engines for high performance. The Crossfire is the first car I've modded very seriously. With that in mind, I have some concerns that hopefully those here with more experience can help me out.

First, let me say what I've done so far:
NeedWings CAI and Code3 Pulley - that's it!

What's coming:
NeedsWings Intake Manifolds, 6mm Phenolic Spacers, and ECU Tune

My concern:
In order to get a good custom tune, I need to install the intake manifolds and spacers, and run it either on a dyno or do some data logging to send to the tuner. I've read many warnings of the dangers of running the engine too lean. Also many have said that the increased air flow of the new intake manifolds will lean out the air/fuel mix.

Questions:

1. What exactly is the danger of running too lean? What will happen / break?
2. So, how do I run the car safely while data logging it before I get the tune?
3. Is it safe to run the car at highway speeds for an a half hour or so with the manifolds installed, but without the tune?
4. Is it safe to run the car (with manis, without tune) at the 1/4 mile track to get those data logs for the tune?

Thanks in advance,
Tom

 

Anyone? Anyone? Beuller?

 

Hey Tom,
I am surprised that you have had no hits on this. Maybe you should post it in the SRT section specifically. I will answer your questions the best I can.


1. Running lean will cause the engine to “detonate”. This is the main cause of severe engine damage. The good news is we have VERY strong engines and I have seen the cars handle 17+ AFR and still did not hear the tell tell sound of detonation. Most cars would have stopped running!!! 240M3SRT6 showed me this

2. You will only experience potential issues at Full Throttle so there are no problems.

3. Yes

4. Yes, but why do you need “data logs”

In Motion has a specific tune for your future mods so you should be good to go. I personally have the LET tune but I do not have the Needswings Manifolds and I know Rob worked very closely with In Motion to develop the tune for your set up.

Your Code 3 Pulley produces the same boost levels as the 178mm ASP that Rob is running so I do not think you have anything to worry about except paying for REAR TIRES!!!

Good Luck~

 

1-3 are spot on, let me touch on #4
id recommend you get the tune installed before you go drag racing. we needed to create that tune due to running a little on the lean side at the track, nothing like the 17+afr but we were dipping into the 13's where i didnt want to be. we want to keep the afr in the 12's for sure, with the tune you should be around 12.5-6 afr which is perfect IMO. datalogging will let us verify many things on your car. get the tune in, go to the track and enjoy while datalogging, then send over the files and i can interprit for you and if needed we can have the tune adjusted specifically for ya.

 

Thanks to both of you for the good info.

As it turns out, I've chosen not to go with InMotion. I started a conversation with them about getting my tune, and we got off on the wrong foot. I got pissed off and decided to use a different vendor. No offense to Rob. But I was just not getting the warm fuzzies from InMotion.

I've ordered hardware/software from TVT that will download my ECU to a file on my laptop. Then I'll send the file to LET via Tony (TVT) along with some data logs and they'll create my tune. Since I'll probably be one of the first NeedWings manifold cars that LET will tune, I expect there to be some back and forth tweaking on the tune until its just right.

 

tom2112, I hope you don’t mind me piggybacking your tune questions.

What parameters are solicited when data logging for custom tunes?

 

I know how you feel. I am sure they do a great job, but when I called In Motion, I felt like an interuption, not a customer. I called LET and Jerry was awesome, answered my questions with logical answers I could understand and even had me send my ECU to his Vacation spot in Florida so he could tune it and get back to me ASAP. He did not want me to have to wait for his return home!!!

I am real interested in Robs Mani's too, but don't have the time for the R & D. As soon as you have all the bugs worked out, I may buy a set and send LET my ECU for an update.

Good Luck~

 

Hope this can clear up some of your questions. Regarding what is to lean. In an internal combustion engine what you have running on petroleum "complete combustion" of the fuel is approximately 14.7:1 air fuel ratio. Anything above this 15 ,16,or 17.0:1 is lean to very lean indicating a problem mechanically or by tuning. Ideally for an engine naturally aspirated you want (and this is a ballpark because every engine is different in design) to be somewhere at 13.8:1 at the beginning of your run and to finish at redline in the area of 12.5:1. For a forced inducted motor it will of course be a lot richer. For best results tuning on a "loaded" dynamometer where you can input your vehicles cd (coefficient drag) and frontal area for real world simulation is ideal. Mail order tunes are decent but they are based off of someone else's results that may or may not be exactly like yours, and are generally a lot cheaper in price than "actual tuning" on a dynamometer. For example I've seen 10 C32 AMG all make different horsepower on my dynamometer on the same day, and the highest made being completeley stock with 1,600 miles on it make 327 SAE corrected horsepower. So a tune for the guy making 299 rwhp may not be what's good for the guy making 327 rwhp. Alot is generally left on the table and in some cases to much can be done to the tune where it's actually a decrease in performance be it to much timing to little of fuel or the exact opposite.