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Did the whole nine yards....Heads, Cam, Intake, Harmonic, 42lb injectors and Holley Rails. After the tune it seems rich at idle and you can smell the gas.
The exhaust tips have black soot on them all the time. I can't determine the AFR is there something I can look at to figure out this issue?
Car runs great after 2000 RPM.
The guy having tuning software doesn’t mean he’s a tuner.
At this point I’d doubt the entire tune.
Posting your tune gets real answers. The details are very minute, just saying you smell gas (got cats?) and your pipes are dirty mean you get zero true results. All we can say is find a different tuner.
The simplest advice is pay for another tuner. If you don’t have ability (software) to post your tune then you have nothing we can help with.
It sounds like you are just seeing the downsides/tradeoffs associated with running a bigger cam. The engine is less efficient at low rpms and due to valve overlap, unburnt fuel is getting kicked out the tailpipe etc. You will smell it regardless if it's a little lean or rich.....I'm guessing closed loop is still enabled so it's probably just about right AFR wise.
I have 226/230 113 so pretty similar to yours in the grand scheme of things. Yes it has some gas smell and will shake the car a little. You could get the idle RPM raised to reduce to shake, but it also won't sound 'as good". I idle at 800rpm.
That cam is big enough with only 347ci engine that you WILL sacrifice idle quality... Plus the LS is 114*.. If you had 116* the idle would
be a bit better.. It's all in the cam timing/overlap/duration is the reason why it "seems" rich and smells more at idle...
Some of this can be helped with a really good tuner, but some is just the facts of life.. You have moved the powerband
of the engine up into the higher rpms, which is what I assume you wanted with that cam to begin with
Cams can be tamed at idle, if you get the air and spark right. Fuel smell is tough to remove with overlap, but can be improved with delaying the injector timing 30-40 degrees or so. It’s a good starting point. My Camaro’s EOIT is set at 360, so about 60 degrees later than stock. I have 80# though since that car has a 427 and maxes the cylinder airmass out easily at 4K rpm.
To tame a big cam, let the spark adaptives do their job. Set the base spark at the highest registered MAP value (aka the lowest seen on the raw number, lower the better = better vacuum) and then on the proportional spark adaptive make sure it can reach at least 30 degrees in correction. Aka, if base is set at 20, make the correction 10 degrees, ramped in obviously, starting small. Also set your base idle tables to 30 in the 0 and 400 columns and interpolate them to give a slope to your regular idle area. It will make the 400 column something like 26* in most places. We call that the “stall saver”....
Here’s what I’m talking about... watch the sawtooth pattern as idle adaptives kick in and keep the idle running smooth. I was driving the RPM down with the scanner controls, just playing around and seeing where it got unstable. I managed to get it down in the 500’s and this cam is a 244/252 @.050, 114+4 20* overlap, with a FAST 102 combo TB and Intake. Compression is 11.8:1. Also note, 80# injectors too. I’ve had to alter the data in the idle regions A LOT to get the spikes to cease and the AFR where I want it. The min pulse width is the focus area there, as they can only close to what that number is. If it’s too high, you’ll have problems.
Good info Jim.
That isn’t a big cam at all for a 346. I’m at 226/230 114+1. Idles nice at 875.
I’m auto trans with a stall, so I don’t notice issues with below 2000 rpm.
Shaking is subjective. But even with poly engine mounts, it’s not something I notice. It’s a hot rod!
I let the tuner figure the cam and 42lb injectors were part of it....Runs strong after 2000 RPM just saying.........
Where did you get your car tuned? And I used Brian @ dinosaurjuicetuning - he lives up your way and he is pretty impressive if you want his contact info.
Where did you get your car tuned? And I used Brian @ dinosaurjuicetuning - he lives up your way and he is pretty impressive if you want his contact info.
02 c5 had exhaust done new cold air on way home car sucked water up cold air bought new mass air flow took to Indiana muscle car for a tune car ran good for a week now wont burn off tires
06-30-2020, 06:39 PM
Seems Rich After Tune
