PDA

View Full Version : 240sx LQ9 tuning issues



devlmaycry
July 27th, 2011, 12:47 PM
--------------------------------------------------------------------------------

Ok, so I'm looking at making back into my tuner here in a week or so to get my gas mileage issues lined out hopefully. Here are my specs of my 240sx with lq9 swap tuned on EFIlive:

Engine: 2003 Cadillac Escalade LQ9 Iron Block 6.0L 10.1:1 compression
Heads: Pontiac G8 GT L92/LS3
Intake: 2010 Camaro pull-off LS3
Throttle body: LS2 2005 GTO 90mm DBW
Cam: EPS 222/230 .597/600 114LSA
Lifters: LS7 GMPP replacement lifters
Pushrods Manley 7.4000 stock length hardened
Springs: PAC 1518 beehive
MAF: Stock truck MAF
Gas Pedal: 2003 Escalade
TAC module: 2003 Escalade
Dr. X-link For full throttle range
Transmission: 2004 GTO 6spd
Clutch: LS7 clutch kit with flywheel
Rear End: J30 VLSD R200 3.916 ratio
Tire Height 25" (255/40/17 on 17x10" rims)

The few issues I've had were cooling (fixed with bigger fan) I now top out at around 210. I've also had an issue with high IAT temps, like around 150ish at idle, fine at cruising speeds. I think that is fixed, but will be able to tell here in a day or 2 once my gauge arrives that lets me see all those readings. I still have a manifold that's leaking around where it bolts to the exhaust. I have since removed my cat and replaced the ricer muffler. The y-pipe still needs cleaned up though.

On the tuning day the tuner used the stock 2003 escalade rom to do the tune on EFIlive. He had some issues, due to limited experience with DBW setups and truck PCM's mated to 6spds, with getting it to want to tune. At first it was only putting down like 200hp and was pulling all the timing out. He tried a couple different roms and finally went back to the escalade one. After looking at all the posible settings and turning a bunch of stuff off he got it to quit pulling the timing. Once it was finally said and done I was putting down around 330whp and 340wtq. Lower than what I had hoped, but was told it was ok considering at that time it still had the cat on it and the y-pipe is really restrictive, and fixing these issues would net maybe 40 more hp/tq

So the problem is as of right now I'm only getting around 12mpg on a good tank. My AFR runs around 13.5-13.8 most of the time when cruising with fluctuations upto 14.5ish. I keep feeling some light bucking at lower rpms <2000, but no CEL coming on.

What things should I be looking for when I go back to the tuner to help with this LQ9/T56 tuning?

joecar
July 27th, 2011, 01:52 PM
IAT is too high, can you plumb intake duct for cold air (from outside engine bay).

If you can get it to run in Closed Loop, your part throttle AFR will be 14.7, this will use less fuel.

devlmaycry
July 28th, 2011, 02:09 AM
Yeah when I was at my buddies shop fixing my gas pedal I relocated the intake to outside the engine bay under the bumper. My ultragauge should be here Friday and I will be able to check my IAT's then to confirm that they have gone down. When Cruising my IAT was around 120 which should be ok right? Is there anything out side of my IAT's I should be looking for? I know I should be seeing around 14.7 on a regular basis instead of the 13's I see all the time with my AFR.

devlmaycry
July 28th, 2011, 02:11 AM
Oh, and I would be able to post log/tune files if I was the tuner and had the stuff on hand. Can these files be copied to a thumb drive? If so I can ask for a copy once I get my retune done here in a week or so.

Thanks for all the input guys and keep the ideas coming!

joecar
July 28th, 2011, 02:34 AM
IAT 120°F is too high... IAT should be close to ambient air temp... e.g if ambient is 80°F then I would expect IAT to be no higher than 82°F while cruising along at say above 45 mph... you need to find a way to duct cold air from outside and in front of vehicle... if you don't do this then the PCM's dynamic air temperature model is incorrect.

AFR 13: how are you seeing this...?
If you're looking at the pid GM.AFR then there are several problems that need to be looked into, post your log and tune files...
yes the files can be copied to a thumb drive and posted here...
but first get permission to do so from your tuner.

joecar
July 28th, 2011, 02:35 AM
Post pics of your engine bay (and car).

devlmaycry
August 1st, 2011, 05:07 AM
I have an LC-1 wideband for my AFR's. I recently hooked up my ultra-gauge so I can now see my IAT's. At idle in 90+ weather is showing engine temp of 190ish with IAT at idle hitting around 114-116. When cruising my IAT is close to ambiant, Lots of heat off the asphault at a stop plus the intake pipe likes to heat soak at idle a little. I will post some pics here tomorrow, I need to get some current pics of the engine bay anyways. I have a built thread on silviav8forums under my user name with some pics.

Timing advance seems to run around 36 at cruising with spikes upto 42.

I should be able to post up the logs somethime next week once I make it to the tuner again. I need to get my y-pipe replaced this week before I take it to him so there's no more outside factors affecting the tune ie exhaust leaks, high IAT's, and cooling issues. Been working out the bugs for a couple of months now, and think I'm down to just the final exhaust leak and re-rerouting.

devlmaycry
August 1st, 2011, 05:22 AM
Here's a few pics. I know I need to seal off the opening from the engine bay, and insulate the intake piping if possible to try an maximize IAT temp reduction.

http://i1013.photobucket.com/albums/af260/devlmaycry/SAM_0853.jpg
http://i1013.photobucket.com/albums/af260/devlmaycry/SAM_0851.jpg
http://i1013.photobucket.com/albums/af260/devlmaycry/SAM_0850.jpg
http://i1013.photobucket.com/albums/af260/devlmaycry/SAM_0849.jpg
http://i1013.photobucket.com/albums/af260/devlmaycry/SAM_0848.jpg
http://i1013.photobucket.com/albums/af260/devlmaycry/The%20new%20paint%20job/SANY2351.jpg
http://i1013.photobucket.com/albums/af260/devlmaycry/The%20new%20paint%20job/SANY2354.jpg

joecar
August 1st, 2011, 05:40 PM
The cone filter bends the incoming airflow almost 90 degrees, the airflow is turbulent for about 8-12 inches past the cone filter, I see your MAF is located immediately after the cone (i.e. where airflow is turbulent).

joecar
August 1st, 2011, 05:42 PM
Your "Corvette" engine looks like it came from the factory in that engine bay, nice transplant job :cheers:

devlmaycry
August 2nd, 2011, 12:08 AM
Yeah unfortunatly I will have to deal with the turbulent airflow. My options for mounting my MAF in an area of nice straight air also sets it in an area of extreme heat. The MAF still has the honeycomb in it so that's a plus since they are supposed to help line out the air before it hit's the sensors. It looks like on the current configuration my IAT seems to be undercontrol, but I would like to insulate the intake from the bay heat soon. It will still heat soak to 120-130 if I get stuck in traffic in this 90+ degree weather with heat indexes in the 100+ area. As soon as it starts rolling and getting fresh air it instantly drops to to around ambient.

Thank's for the complements on the car! It's been a learning process working out all the small bugs, but well worth it. Everyone thinks it's a vette motor with the beauty covers on it, but I like them becuase they cover up the wiring, and makes it look cleaner. I usually skip all the differences and the specs unless they seem to know cars and have a real interest.

devlmaycry
August 2nd, 2011, 12:28 AM
Looks like apexi makes a dual cone filter for a hefty price that might help with some of the turbulence, but it will have to wait until I can get $115ish to spend.

joecar
August 4th, 2011, 08:20 AM
Be sure to locate the MAF away from the filter and any bends in the duct. to avoid turblent air from misreading the MAF.

devlmaycry
August 5th, 2011, 01:09 AM
Well lowering my iat's didn't help my mileage any. Im pretty sure my pcm is still set to auto trans. I remember him changing some settings on the auto menu about time ranges, but pretty sure it was never switched to 6spd manual. I shouldn't be getting 10mpg from my setup town and highway.

devlmaycry
August 16th, 2011, 07:50 AM
Ok, got my exhaust has been fixed. Now it seems my tuner might be on vacation since I can't get ahold of him. However, hopefullly I can post a log/tune file once I can get in touch with him and get this thing lined out *fingers crossed*. My AFR has been better since the exhaust has been fixed, but I still get bucking at cruising speeds and is more pronounced under 2k. So hopefully it just needs a few more runs done to smooth everything out and fix my horrendous gas mileage. I should be able to leave blackmarks coming out of first, but all I get is a little chirping and what feels like it dogging down above 5k-ish.