GTM Motorsports Oil Cooler

Denny McLain

Thanks for the information. Very informative and useful .

Water Temps......... The first time I dynoed my 370Z it sat 30-45 minutes with the hood closed going on the dyno. After the first pull it sat 30 minutes with the hood open and a fan on it. It gained 10 hp on the second pass. My opinion at the time was that it was heat soak which is common on numerous cars. The SVO Mustang is famous for losing as much as 60 hp when they get hot vs cold. The opposite is LSx engines which usually make the best hp on the third pull and don't seem to mind running a little hotter.

After getting the Cobb AccessPort and logging my timing, I've noticed the car pulls more timing out when it get hotter. Logged two runs with one at 184 water temp and the other after a couple of passes @ 207 degree water temps. The car pulled out 2 degrees of timing.

Now I'm not so sure about my original assumption of heat soak as reduced timing certainly will kill hp but there is a definite 370Z horsepower loss association with heat. The reason for the oil cooler for me was frankly to see if the oil temps were a factor. I'll repeat the logging and add the oil temps into the formula to see what the timing does.

My current feeling is the cars will make more usable power if they run cooler. If you read David Vissards book, he notes that small block Chevy's sweat spot for hp is 170 degree water temps. Hotter factory temps are usually done for emmissions and engine longevity.

I'm sure sooner or later someone will come out with a thermostat and I'll do my thing logging the timing to see what it does and also more dyno time.

Modshack

There is a timing pull and you'll naturally heat soak sitting on a dyno table...
It's not necessarily water related though. Your fans trigger at 212 dgrees and shut off at 202 so this is relatively well conrolled when sitting. On the road,temps will run around 182. Most of it (timing pull) is coming from elevated IAT (intake air) temps. I monitor both IAT's and water temps full time on my Scangauge. I've also posted graphs here showing the timing pull on Corvettes when the IAT's elevate. It's much more significant with IAT's compared to water temps. It's not unusual to see IAT's go as high as 150 degrees on the 370 when heat soaking. As close to ambient is where you want to be, which is why the injen and stillen G3 work as well as they do...They pull air from outside the engine bay. The stock system does too for that matter. None of this design is very effective on a dyno as ther's just not enough air flow. This is one reason I designed the Fang vent system to get cool air to the intake. My temps run only 5-10 degrees over ambient when rolling for minimal timing changes. Stop in traffic and the IAT's elevate pretty quickly which is why the car feels sluggish in these condidtions. Mine will come back down virtually immediately as soon as cool air starts getting fed to the intakes. IAT's are genrated at the MAF just upstream of the airbox.
Cooler is always better, but a cooler Water temp won't necessarlily change the IAT problem which IMO is the area that needs to be addressed..
I've played with this on both my previous Corvette and Audi TT and designed systems and insulated airboxes to address it. Finding ways to reduce IAT's worked nicely on both as it has on my 370..

__________________

Steal my car! (SOLD)...Now Porsche Cayman S
Oil Cooler DIY: Here!

Denny McLain

Think we have a fair amount of parallel thinking going on here. Here is how I lowered the intake temps on my Corvette. Ram Air intake with a sheet metal intake.

Ram Air Intake picture by dennylmclain - Photobucket

Sheet Metal Intake picture by dennylmclain - Photobucket

This is what I've done so far to lower them on the 370:

Heat Barrier on Gen 3 intake picture by dennylmclain - Photobucket

Heat barrier in engine bay picture by dennylmclain - Photobucket

Basically two layers of thermal barrier wrap with four layers over the MAF sensors in addition to cutting a center hole in the Styrofoam bumper to see if that would deliver more air to the K+N filters.

Looks Ghetto but like you, I've been monitoring my intake temps and yesterday when starting the car cold in 80 degree ambient weather and just driving, the intake temps were 8 degrees over ambient going down to six degrees when the throttle was applied. Really just now trying to get down to the nitty gritty to figure out what the cars like and don't like. Going to monitor water temps, oil temps and intake temps to see if I could figure some consistency.

Bought the tubing to duct air better to the filters and tried to do it Thursday, but just wasn't happy with the routing and securing it when putting the front fascia back on the car. Was in bed this morning thinking about ways to do a true ram air system for the car. I'll keep playing with it to see what happens.

Big believer in dyno time and also a big believer in what I would call "pragmatic power" which doesn't necessarily show on the dyno. Usually dyno pulls are made under the best condition possible which isn't what you encounter in every day driving.

For every 1 degree of air intake reduction you gain 1 percent in hp and if you can lower that during real world driving, you struck oil in my opinion.

Nice thinking and nice work!

Modshack

Thanks......Yeah, I think we are both thinking the same things here..

I'm also thinking, given the extent of your G3 insulation effort and resultant temps, that it won't get much better than that. I'm seeing the same numbers with my insulated intake and vent system. While I may be able to improve it slightly by sealing the box to the front radiator brace it may not be worth the effort. My silicone tubing is probably more resistant to heat pick-up than the stillen aluminum which helps too.

On neatening up the Forced air, I'm guessing you saw my DIY on that:
http://www.the370z.com/diy-section-d...ur-airbox.html

We had also explored the G3 venting on another thread somewhere, and I think a Vette-air scoop mounted below the aluminum impact bar could be effectively used to get air to those boxes..



Keep on working on it....We'll get this figured out yet!

__________________

Steal my car! (SOLD)...Now Porsche Cayman S
Oil Cooler DIY: Here!

Denny McLain

[QUOTE=Modshack;195583]Thanks......Yeah, I think we are both thinking the same things here..

I'm also thinking, given the extent of your G3 insulation effort and resultant temps, that it won't get much better than that. I'm seeing the same numbers with my insulated intake and vent system. While I may be able to improve it slightly by sealing the box to the front radiator brace it may not be worth the effort. My silicone tubing is probably more resistant to heat pick-up than the stillen aluminum which helps too.

On neatening up the Forced air, I'm guessing you saw my DIY on that:

We had also explored the G3 venting on another thread somewhere, and I think a Vette-air scoop mounted below the aluminum impact bar could be effectively used to get air to those boxes..

QUOTE]

Again, we are thinking the same and my feeling is 6 degrees ain't that much and maybe it ain't so broken after all. Was also thinking about a C5 or C6 type scoop and ways to seal off the filters from radiator heat.

No I didn't see the post and will read it closely, but I will say one thing ....Your intake looks a hell of a lot better than mine. You can take me out of the Ghetto, but guess you can't take the Ghetto out of me.

Just reviewed my last log session in which I made (4) 0-80 mph passes in a row and the water temps were between 205 and 210 and there was basically no change in timing from any of the runs. No intake or oil temps logged so I'll replicate it playing with cooling the intake temps and oil temps down compared with hot.

You may be right regarding the trigger that shuts down timing may be intake temps or 5 degrees of variance just doesn't make much a difference. Now I did see -2 degrees logging a 184 degree run vs 206 degree run but that may be coincidence as I'm sure the intake/oil temps were also different.

Modshack

Yeah....Hard to tell what the trigger is on the Nissan ECU. On the Vette (LS3) it's easy to see (and also easy to change the values with software like HP tuners). As I recall from my Vette logs there was no Water temp related timing pull until temps exceeded 235 or so....

On my Fang vents, it should be easy to route the hoses to the G3 filters instead of into the Radiator brace as i did...

As you can see from this chart, there is no reference or scaling to ambient, so over 86 degrees IAT you're hosed no matter what unless you make a software change. I recall I had shifted the table a column to the right...(time to move north!)
IAT temps and timing pull:

__________________

Steal my car! (SOLD)...Now Porsche Cayman S
Oil Cooler DIY: Here!

Denny McLain

[QUOTE=Modshack;195627]Yeah....Hard to tell what the trigger is on the Nissan ECU. On the Vette (LS3) it's easy to see (and also easy to change the values with software like HP tuners). As I recall from my Vette logs there was no Water temp related timing pull until temps exceeded 235 or so....
QUOTE]

Both Lt1.edit and HP Tuners (Expecially HP Tuners) is light years ahead of what Cobb is ofering in capability to get into the computer. Was pretty shocked when I couldn't find something as simple as anything to effect the onset of fans. At least for the most part the oil cooler should take oil temps out of the equation.

Hopefully the capabilities wil change, but for my C4 there are water temp tables you can play with that for sure enrichens the fuel and would have to look if there are tables that effect timing. Think so.

It's a moot point but my problem is I changed out computers and need to reload the tuning software to take a peek at all it really does.