Not running hot enough?

sambo · #1 (**permalink**) 02-04-2012, 09:06 PM

I took the Cobra down to EFI Dynamics during the week and Erol had a look at the tune to make sure everything was in order before I re-attempt the IM240. It made 230kW at the rears which I guess is OK for a stock VE tune and VZ cats. He altered the fuel maps a little to compensate for the non-factory intake and MAF position, something about trimming the fuel a little earlier to make it as close to factory as possible.

He gave it a few pretty hard runs on the dyno and the engine temp didn't get much over 80 degrees. As we know, modern engines are designed to run at about 95-100 to burn off as many pollutants as possible. He suggested running a hotter thermostat or restricting flow through the cooling system somehow.

Given that the IM240 has been relaxed to meet ADR 37/01 at 100% (ie, half the previous levels?), is a 10 degree temp increase going to make the difference between pass and fail? I'm thinking no.

A new thermostat is $70 plus whatever coolant I need to replace. Peace of mind I guess?

boxhead · #2 (**permalink**) 02-04-2012, 09:27 PM

Can you adjust the fan to come on later?

Modena · #3 (**permalink**) 02-04-2012, 11:14 PM

I thought the fan was controlled by the ECU anyway.....it shouldn't come on until the ECU determines that it is needed?

benny s · #4 (**permalink**) 02-04-2012, 11:17 PM

Sambo, Jim lowers the fan cut in temp when he does the ecu i think it is 95 c back to 87 c only a guess.You could get some cardboard and cover a small section of the radiator cheap and easy way

sideshow · #5 (**permalink**) 02-04-2012, 11:34 PM

should be 95 on and 90 off
how is he reading the engine temp
thru his tuning software
or thru yr temp gauge in the dash

cant see y u cant get over 80 as a normal theromostat opens at 81ish 83 ish
did u put a lower temp one
paper over radiator wont go down well with the rta tester i recon

sambo · #6 (**permalink**) 02-05-2012, 04:45 AM

No the fans didn't even come on guys. It takes a lot of heat soak at the lights on a hot day before she gets over 90. He was going off my gauge which seems pretty accurate against the fan temps that sideshow mentioned.

Any thoughts on whether 10 degrees hotter is going to make a very big difference to pollutants at the tail pipe? I would've thought it was minuscule compared to what the cats are achieving.

Modena · #7 (**permalink**) 02-05-2012, 04:48 AM

The dyno fan must be very good - so......let it idle. 10 mins, 15 mins, whatever it takes until the fan comes on, what is the temp then?

sambo · #8 (**permalink**) 02-05-2012, 05:01 AM

Usually a bit over 90 Modena, according to my gauge.

Has anyone passed the IM240 with a VE Commodore tune and the rear O2 sensors switched off?

bobcowan · #9 (**permalink**) 02-05-2012, 08:23 AM

Quote:

Originally Posted by sambo

Any thoughts on whether 10 degrees hotter is going to make a very big difference to pollutants at the tail pipe? I would've thought it was minuscule compared to what the cats are achieving.

Yes, it does. That's the whole point of the factory using the higher temp. The cats need to be at a pretty high temp to do their job. Getting the chamber temps up there helps the cylinder charge to burn better, and then puts more heat in the cats.

When it was on the dyno, did they measure CO? Sometimes you can get a pretty good idea from the dyno run.

If the engine is tuned well, you should be able to pass a smog test in this country. But (obviously) I don't know much about your country.

jhv48 · #10 (**permalink**) 02-05-2012, 08:48 AM

Do you have the correct temperature thermostat in place?

Aren't F/I engines supposed to have a 190?

sambo · #11 (**permalink**) 02-05-2012, 12:46 PM

The L98 is meant to have a 187F (86C) thermostat.

xlr8or · #12 (**permalink**) 02-05-2012, 01:43 PM

Thermostat sets minimum temps. Radiator and fan controls the max temp. If you need to increase normal operating temp you need to change the thermostat. I would double check temp sensor and guage accuracy first to verify what it is actually running at.

sambo · #13 (**permalink**) 02-05-2012, 01:59 PM

OK I just spoke to the tuner and he was working off the ECU temp, so that eliminates faulty or inaccurate temp senders and gauges. It might be time to drop the thermostat into a pan of water on the stove. Must do this before the wife gets home

sideshow · #14 (**permalink**) 02-05-2012, 02:44 PM

hey bobcowan
name me one modern tuner that knows what co is hehehehe
not many use a 4 or 5 gas annalyser these days

kyleb · #15 (**permalink**) 02-05-2012, 04:22 PM

Sambo,
I ran the cooler thermostat (albeit that is correct they do run them hot for better combustion therefore less for the cat to clean up ) in my LS1 with the standard corvette tune and the older cats and it got through, therefore as long as your cats light off and your engine is running smooth with no misfire you should be fine. Also it helps if Jason doesnt stall your car on the Dyno.... that threw it a bit on the first run.
Believe it or not it more comes down to how well they drive it on the dyno.
To give you an idea, if they short shift in the drive cycle that means less revolutions for the time in the cycle therefore less emissions, so they are supposed to know exactly when to shift, also shift smoothly and not chase the drive cycle.. If they don't it has an adverse effect.
If all else fails Jason likes scotch.

sambo · #16 (**permalink**) 02-05-2012, 04:57 PM

G'day Kyle. Very interesting... when did you pass the test? What did you mean by older cats, VZ or earlier? Also how close are they to the heads? Mine are at the end of tri-y headers.

sambo · #17 (**permalink**) 02-06-2012, 05:30 PM

I started the car last night in the driveway and let it idle until the thermo fan came on. It took about 8 mins from a cold start and my gauge read 95 when it kicked in. Within a minute it was back to 90 and the fan turned off. At least my temp sender and gauge are consistent with the ECU.

I rang VIPAC and they confirmed it is a warm test, so the engine will be close to ideal running temp before the test.

Booked in for next Tuesday morning, wish me luck.

Merv and Sharon · #18 (**permalink**) 02-06-2012, 08:23 PM

Lots of good luck coming your way Paul. Your preparation sounds excellent.

sideshow · #19 (**permalink**) 02-07-2012, 12:21 AM

just get the exhaust very hot just before u get to test
if u have genuine cats of a Holden or ford it's easier to pass
cats from your local exhaust can sometimes fail the test

kyleb · #20 (**permalink**) 02-07-2012, 01:06 AM

Quote:

Originally Posted by sambo

G'day Kyle. Very interesting... when did you pass the test? What did you mean by older cats, VZ or earlier? Also how close are they to the heads? Mine are at the end of tri-y headers.

Sorry it took so long to reply...
I had a look at the cats and they are marked 2002... They are placed about 500mm from the heads and I passed the IM240 in October just after they relaxed the test requirements.. Cheers