chillin014

I recently purchased my 02 vette with an LS2 swap, some mild head-work, FAST intake manifold, full exhaust, and what looks to be a pretty "large" cam (XER287HR-12).

The car has not been tuned and has some drive-ability issues at low speeds. I have read this could be due to fuel timing and the larger cam. My most immediate concern is that I am trying to pass inspection and it's apparent that at idle the car is running rich. I need a quick solution to get it to pass the smog test.

Initially my plans for the car were to get a Diablo intune or similar handheld and play with the tuning myself at my leisure and learn/improve over time. I've always had an interest in tuning and have a little past experience. I know I could drop the car off at a local tuner but I don't really want to spend the money and then again later down the road if I decide to change the cam out or whatever. I'm not really concerned with squeezing every extra horsepower out of the car, it has plenty as-is.

Because I am in a pinch I'm really looking for some guidance and help from my fellow forum members and I apologize for my minimal amount of research. I may take my car to get inspected tomorrow just to see how far off it is. The urgency is that I need to pass in the next 2 weeks to actually transfer title on the car. What do you guys recommend? Consider a dyno tune to be my last resort!

Thank you in advance!

enoniam

May be quite difficult to not have some level of "richness" in the exhaust odor with that large of a cam even when tuned well. I wouldn't even try a hand-held. I'm an HPTuners user - that or a similar setup is what a dyno shop would use. If you want to try your hand at doing it yourself I'd use HPTuners or a similar product such as EFILive.

There may be someone local to you with one of those products that for the cost of licensing your car's VIN with HPTuners or EFILive could work with you and save you some $s...

chillin014

Thanks enoniam. I guess I was overly optimistic in hoping that I could order something online and quickly make a few tweaks but realistically the modifications on this car make for too many variables.

I'm going to take the car down to the inspection shop just to see how far off it is from passing (aside from just the smog). I may have to resort to plan B and "buy myself some time" so I can get the car registered.

chillin014

Great news! By some miracle I have passed the inspection. Without the urgency I can now do a little more research. At least I know that the handheld is off the table though.

I watched some videos on HPTuners and it looks pretty impressive. As far as I can tell for the cost of one dyno tuning session I could buy the software and be pretty much set with the exception of maybe a wideband O2 sensor.

Enoniam- would you say HPT is the most commonly used tuning software for the C5?

tblu92

Going from a 5.7 engine to a 6.0 requires major changes to your tune--Cannot be usually done using any handheld tuner-You must change between 50-100 tables in your base tune to reflect the 6.0 in regards to airflow--fuel and spark--This will address all the issues you may be having---dying--idle--poor starting--surging etc----I have tuned many of these type engine swaps---and it is a tedious task but doable----In my opinion you have NO choice but to go to a tuner with HP or EFILIVE

chillin014

Hmmm. I see what you are saying. Now that I think about it, this car was tuned at a local shop by the previous owner which explains why it runs as well as it does. However it was not tuned after the cam was installed and I think that is what may be causing most of the issues. The low speed behaviors and the rich idling is my primary concern right now.

I want to learn how to do the tuning though. What if I want to make adjustments in the future? I hate the idea of being dependent on someone else to tweak it every single time. And I certainly do not have the budget to throw out 500 bucks an hour every time either. Is it really not logical to just buy the software, do some data logging and tune it over time with help from fellow forum members or other resources? Seems like other guys are doing it with some patience and willingness to learn....

schpenxel

It can be done but don't expect it to be easy to get started. There is a lot of terminology and things you will have never heard of that you'll need to understand in order to "tune". HPT/EFILive give you direct access to hundreds of tables.. you put the wrong # in, you get the wrong result out. No nannies, nothing checking behind you.

The HPTuners forum is decent about helping, but they do get pretty tired of the same beginner questions every other day. It takes time to understand it all. At the end of the day it's air, fuel & spark.. but actually figuring out when to do what and for how long isn't easy

You'll need HP Tuners PRO (or EFI Live if you prefer theirs) and a wideband O2 sensor setup to get started. Greg Banish has some good books/DVD's too. I would read a few of his books first as they aren't expensive.. then see if you're still interested. If you are, then the HPT/wideband setup + his beginning DVD is a good next step IMO

enoniam

The #1 thing you need if you want to get into tuning yourself is whether you will enjoy getting into the technical details. I'm a senior electronics engineer working in naval aviation that doesn't do much detail technical work on the job any more. Tuning for me feeds my interest in doing technical detail work. Some people don't have any desire to that type of work however.

It really isn't that hard to do much of this tuning. It can be a bit time consuming however knowing what to do once you get the tool. When I replaced the supercharged and meth injected 5.3 engine in my truck with a 460 hp 6.0 crate engine I made some tweaks to the tune, mostly just adding some idle airflow and rpms so that it would start and idle nicely on the initial startup attempt, which it did. I've since tweaked the tune in the truck over 30 times, adding timing and then taking away where the knock sensors were seeing knock, some more dialing in of the idle characteristics, changing some shift points, etc.

If your car's tune is primarily just needing to be updated because of the cam you can easily make some changes that will show some improvement, but with a cam as large as what you are running it will likely take you a while to dial in some changes that will make more significant changes. For me, dialing it in is a very satisfying experience. I like the "I did it myself" aspect of it, much as I did when I was playing a loft of golf and making my own clubs with components sourced from Golfsmith. The process of tuning actually adds to my enjoyment of my vehicles as it's almost an intimate aspect of getting to know your car and how its brain "thinks" and makes it do what it does.

There are people on this forum and others who will also be happy to give some advice on how to proceed so you will not be doing it solely on your own. HPTuners runs a repository of tunes that you can download to see how other people have tuned setups - hopefully you can find some similar to how your car is set up.

As far as HPTuners versus EFILive - I believe they are both good and pretty much equal. Tblu92 is the only one here that I am aware of using EFILive, but even when he posts making a change to a particular table I can usually locate a table in HPTuners that may have slightly different name but is doing the same thing. One thing to be aware of if you ever need to call HPTuners or EFILive there may be a big difference in what it costs as HPTuners is in Chicago and EFILive is in New Zealand.

I will add a work of caution unrelated to computer tuning based upon the cam in your car. It has Comp's XE-R lobes which are known for being aggressive but not easy on the valvetrain. Many people running cams with those lobes regularly replace their valve springs. Conversely I ran some Crane dual springs for about 200K miles using them first with a Crane cam and then a Comp with their XE lobes and had a couple of them checked with a spring checker and they still were at spec.

My vette came to me at 91K miles with an unknown at the time cam with Comp's XE-R lobes (220/224 duration at 0.581 lift) and who knows how many miles on the cam and valve springs. At 108K had a lifter fail that damaged the cam and lifter bore. Given how much we drive the car reliability is of interest so the rebuilt engine is now running a Comp cam with their more valvetrain friendly XE lobes and more duration (228/230). Running without cats car does have rich-smelling idle. I've tried tweaking when the injectors fire as well as the O2 sensors' switching voltages - neither helped much if at all with the smell. Got a nasty backfire when lifting off of WOT at high rpms - have since gone back to stock injector firing timing. I could try running open loop at idle but for now am not going to mess with it - there aren't any inspections where I live.

Back to your car's cam though, depending upon what you know about what's in the engine now I'd consider upgrading the lifters and rocker arms and refreshing the valve springs. I'm now running dual Crane springs in my car - dropping a valve is a good way to trash an engine.

chillin014

Excellent ! I'll look into those books- thank you. I definitely don't expect too much hand holding but if I can avoid re-inventing the wheel that will help me make my mind up even easier!

Wow- thank you for this in-depth response. I actually share the desire to get my "hands dirty" and do it myself. That's how I am in every aspect of my life. Obviously tuning an engine with a computer is a bit of a different direction from simply being mechanically inclined, and I understand that it has a different appeal. When I was younger and had more time there was no limit to how deep I wanted to dive into learning about my car. You make an excellent point and as I am re-entering the gear-head world I am relearning what my limitations are as far as interest and time availability. I can safely admit I don't have the desire to re-engineer the ECU (for lack of a better dramatization). But I would enjoy the control, flexibility and even the visibility to see what the car is doing. If the car was not so modified by the previous owner- I would love to just get a handheld and keep it simple but that is not the situation I am in. As they say- how do you eat an elephant?

I am grateful for your info about the cam. I read only a little bit about it online and that is when I found out that it was such a radical grind. I am disappointed that the previous owner went this direction with the cam because I would have been perfectly happy with something more mild. Now, as you are saying, I have to worry about the valve train and other symptoms. My initial plan was to make this setup work for at least a little while until I can choose and install another cam. This is also part of why I didn't want to take the approach of paying a tuner repeatedly.

If the majority of vette tuners are doing HPT, that is what I will go with. I think the first step will be to see what more information I can get from the previous owner about the configuration and go from there.

RonSSNova

I agree with enoniam. I'd be shopping cams first. And I'd look to Martin Smallwood, Pat G or Geoff at eps for a nice custom grind that will run harder, idle better and be much easier on parts.
My own car has a custom by Pat G, idles with a nice chop and is sneaky fast.

HP tuners is really upping their game with the latest tuning SW and especially the scanner.

Go for it,

BTW, I also have an electronics background. 38 years at Tektronix. So learning EFI tuning just seemed like something I needed to do. :-)

Ron

schpenxel

Agree on cam choices.. I went with a Pat G cam, ground by cam motion. They use lobe designs that are much easier on valvetrain than most of the comp cams ones, not to mention using billet cores. I went from ordering my custom cam to having it in my hands in 4 business days with standard shipping. Can't beat that.

romandian

go to the efilive (or hptuners) forum and read for 10 - 20 hours. then decide if you want to get involved in this. when you get the software, go and read for 20 - 40 hours more and youll get the hang of it.

concerning the leaning out the mixture, its possible to use a resistor or operational amplifier in the output of the lambda sensor, although i never tried this on a ls1/2.

chillin014

Hey again all- I've been thinking about your responses and decided to do some more concrete research before coming back for more advice. Here is what I have concluded about the car with more certainty:

LS2 Engine from a 2005 corvette
ETP 215 Heads
XER287HR-12 Comp Cam ( Duration 287 intake and 289 exhaust)
FAST 92mm Intake Manifold
SVO 42lb Injectors
American Racing 1 7/8" headers and 3" x 3" X pipe with high flow cats

I spoke with the guy who rebuilt the engine and he is discouraging me from going too mild on the cam because of the free flowing intake manifold and heads. Is there much to worry about here? I just want something more reasonable for daily driving, it's not like I'm trying to revert to stock! oh also he offered to do the cam swap but says it would be more convenient to pull out the entire engine to do so.....

I have watched videos of other cars with this same cam and they idle much more "aggressively" than mine does. I don't know if that's because my vette is idling too high ( 8-900 RPM) but I'm not getting any of that lopey / choppy sounding exhaust.

Anyway- my next step is to determine what cam will be fitting for my engine and my needs. The sooner I can do that, the more likely I am to avoid paying unnecessary tuning fees and maybe I will ultimately just decide to have a shop tune the car. I don't have so much time these days

schpenxel

I would talk to someone like Pat G about the cam and see what he thinks