RLS IC, EGT, Post IC temps, and GPS speed...

[robains]

Now that my car is back together and running reasonably well, I'm starting to gather up some data on how well my RLS IC is working with a 3.0" pully and EFI ECU, with the mail slot modifications and a very well sealed IC shroud on 91 octane pump gas.

As some of you know this is motor #2 I put together and installed, so I've added a few sensors with alarm triggers that go thru my RacePak IQ3 dash/data logger. Last night I was doing some tuning and putting the car under some good loads (nice 6 mi long hill - pretty steep low traffic 2 lanes either way).

I was logging my A/F, EGT, Boost, GPS speed, Post IC Air temps doing several 120 mph pulls up this hill. My tune still needs work, but under load the A/F were good around 11.6 so I felt reasonably safe as car accelerate well and smooth.

Ambient was pretty cold at 60F with low winds.

Some eyeball findings:
1. Post IC air after several minutes of idle & moderate rpms not moving was 112F (makes sense just sitting in garage reving the engine for 15 minutes or so)
2. Post IC air temp during normal driving 61-71F (on decel no throttle at 80mph it would drop below ambient, again makes sense)
3. Post IC air during load 3rd & 4th gear initially went up to 98F but then started to drop with speed until I was at the top of 4th and it was reading 72F (rev limiter set to 8200 spark, 8300 fuel).

At first I was somewhat baffled, even checked and rechecked sensor calibration vs. real world, etc. etc. So I do another set of runs, getting the motor hot first. Get the same results, only this time I paid attention to EGT, and it followed the same pattern as Post IC air temp. EGT would initially jump to 1350 degrees, but as GPS speed increased to top of 4th, EGT started to drop to 1190.

I didn't expect these results. Contradicts some of the other data I've seen here with the RLS. Once the engine got hot, I expected it to stay hot and get hotter under load. I'm not going to make any conclusions just yet as I don't know if it is a combination of the opened mail slot with the RLS IC and the tightly sealed IC shroud and the open exhaust (aka no bumper), my oil catch can setup, or what. Keep in mind I'm running stock header and stock cat with a very quiet 8" Larini muffler.

I'll try to post some video overlay (data/Trackvision) results tonight or tomorrow along with some charts/graphs.

Rob.

[Thomasio]

Same thing happened to me the first time I logged the RLS intercooler. I thought that I was monitoring ambient temperature or something inadvertently b/c the temps wouldn't continue climbing like with the stock intercooler.

It's good to see independent testing going on.

[robains]

Glad I'm not losing my mind -- this is REALLY good news! My hunch is the combination of sealing the shround, better IC, and rear bumper removal has really optimized air flow both to the IC and out of the engine bay. But watching the EGT go down as well was a real surprise and treat!!

Obviously this wasn't a track test but I did run the car very hard last night going up this hill many times -- it's definitely showing some GREAT promise! My only concern now is that a dyno can't possibly emulate this air flow which would scew a tune.

Need to do some more testing.

[shay2nak]

What's EGT?
When you say IC shroud, is that the black plastic from the roof/clam to the coupler? I'm about to install my RLS IC as well after finally attaching the IC oval housing. I actually went back last night and sealed the inside perimeter of the this housing where it meets the IC. Also, I noticed that the top row of 1" welds were gapless except a couple (light shining through). The bottom row was excellent. I'll seal those as well.


Robains,
another thing you might want to do since you removed the rear panel is to remove the grills on the side intakes. That helps get more air into the engine bay.

AFA dyno testing/tuning, you'd probably have a large fan pointed at the IC.

[robains]

Shay2nak,

EGT - Exhaust Gas Temp -- currently have one sensor on cylinder #4 (my hot cylinder). Yes, the black plastic piece around the IC -- I sealed it up (all the way around from the inside of the shroud) with a bunch of silcone based sealant.

Yeah, I've seen the large fans, but those don't really emulate real world air flow at speed. I doubt many dyno shops have fans capable of generating 120 mph+ wind force over the entire car (that would essentially require a wind tunnel) -- it's not just the IC but the side pods (as you noted) and undertray air going thru the NACA ducts and out the back. Why I think this is important is that so far the data suggests air flow is VERY significant.

[Matt in Houston]

Did you stick with the 550's or switch back yet? Is that still your plan?

[robains]

Still with the 550s for now.

[SUTOL111x]

I do not know if this translates over to 4 stroke, but I did a ton of 2 stroke tuning using EGT gauges in each cylinder and would see cylinder temps drop when richening it up and higher temps when leaning it out. Of course, they ran best right at the edge of too lean until I would stick a piston!

[ZJChaser]

dont go to a smaller pulley. those temps will increase significantly

EGT and air temps look good.

what roof? and are you using the sprayers?

[robains]

Water mist is off, roof is stock 07 Exige S.

too late, I'm at a 3.0" pully vs. 3.2" stock -- but I suspect it is considerably better than my old 2.5" pully.

Got more data tonight, will try to post results this weekend.

I'm from a racing background in stock Honda 125cc 2 strokes and I had an EGT on that motor as well. Yeah, max to lean for optimal power. BUT, 4 stroker is different.

[turbophil]

Rob-

Run the car down the highway at 80mph for about 35 minutes to get the blower good and heat soaked and then start conducting your tests. You've got heat up a lot of aluminum before you can really see how much heat the IC is extracting from the charge... That highway run I mentioned is about the only way I can get the charge temps anywhere near close to track temps.

With all due respect, I can assure you that the IC isn't anywhere 90% efficient when driven hard. The 3.0 Pulley will be pushing 260+F outlet temps when you're really running it hard even on a cool day and there's just not enough airflow going across the IC to pull that kind of heat out of the charge...

Not trying to be a downer, just a realist...

Best,

Phil

[robains]

Agree that I need to do more testing Phil. Problem with doing this on the street is that the IC cools down to quick. But I'll try to find some long empty freeway, but nothing really emulates a track.

80 in 3rd on freeway?

I got more data tonight. Looks like my AFR was dipping into the 10's!! I did drive it for about 30 mins on the freeway before I did my hill runs, but I get the feeling I need a long long long section of deserted Freeway. This might be why my EGT drops considerably under load, running way too much fuel.

What I've noticed is that under load the Post IC temp go down with initial speed increase then slowly start to rise, but after load (slow down) the Post IC temps continue to rise as speed decreases and then fairly rapidly recovers to cruise temps.

I'll post my graphs and video this weekend. But I agree for track duty, the best place to data log is at the track. Maybe in Dec.

It's Ok Phil, we all know you're anti-IC